Merge version 3.39.4 changes into the reuse-schema-3.39 branch.

FossilOrigin-Name: 8102592836dcf6f08749a516e126f3990a20f40866ed4a6e85d134ab49907ece
Version 3.39.4
2022-09-30 12:27:46 +00:00 · 2022-09-29 15:55:41 +00:00 · 2022-09-28 19:19:11 +00:00 · 2022-09-28 13:38:49 +00:00 · 2022-09-27 02:04:52 +00:00 · 2022-09-10 13:50:33 +00:00
86 changed files with 4309 additions and 489 deletions
@@ -140,6 +140,7 @@ GCOV_LDFLAGS1 = -lgcov
 USE_GCOV = @USE_GCOV@
 LTCOMPILE_EXTRAS += $(GCOV_CFLAGS$(USE_GCOV))
 LTLINK_EXTRAS += $(GCOV_LDFLAGS$(USE_GCOV))
+LTCOMPILE_EXTRAS += -DSQLITE_ENABLE_SHARED_SCHEMA


 # The directory into which to store package information for
@@ -419,6 +420,7 @@ TESTSRC = \
  $(TOP)/src/test_quota.c \
  $(TOP)/src/test_rtree.c \
  $(TOP)/src/test_schema.c \
+  $(TOP)/src/test_schemapool.c \
  $(TOP)/src/test_server.c \
  $(TOP)/src/test_superlock.c \
  $(TOP)/src/test_syscall.c \
@@ -480,6 +482,7 @@ TESTSRC2 = \
  $(TOP)/src/bitvec.c \
  $(TOP)/src/btree.c \
  $(TOP)/src/build.c \
+  $(TOP)/src/callback.c \
  $(TOP)/src/ctime.c \
  $(TOP)/src/date.c \
  $(TOP)/src/dbpage.c \
@@ -503,6 +506,7 @@ TESTSRC2 = \
  $(TOP)/src/pcache1.c \
  $(TOP)/src/select.c \
  $(TOP)/src/tokenize.c \
+  $(TOP)/src/treeview.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vdbeapi.c \
@@ -874,7 +878,7 @@ hash.lo:	$(TOP)/src/hash.c $(HDR)
 insert.lo:	$(TOP)/src/insert.c $(HDR)
 	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/insert.c

-json.lo:	$(TOP)/src/json.c
+json.lo:	$(TOP)/src/json.c $(HDR)
 	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/json.c

 legacy.lo:	$(TOP)/src/legacy.c $(HDR)
@@ -1537,6 +1537,7 @@ TESTSRC = \
  $(TOP)\src\test_quota.c \
  $(TOP)\src\test_rtree.c \
  $(TOP)\src\test_schema.c \
+  $(TOP)\src\test_schemapool.c \
  $(TOP)\src\test_server.c \
  $(TOP)\src\test_superlock.c \
  $(TOP)\src\test_syscall.c \
@@ -1 +1 @@
-3.39.0
+3.39.4
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for sqlite 3.39.0.
+# Generated by GNU Autoconf 2.69 for sqlite 3.39.4.
 #
 #
 # Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
@@ -726,8 +726,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='sqlite'
 PACKAGE_TARNAME='sqlite'
-PACKAGE_VERSION='3.39.0'
-PACKAGE_STRING='sqlite 3.39.0'
+PACKAGE_VERSION='3.39.4'
+PACKAGE_STRING='sqlite 3.39.4'
 PACKAGE_BUGREPORT=''
 PACKAGE_URL=''

@@ -1468,7 +1468,7 @@ if test "$ac_init_help" = "long"; then
  # Omit some internal or obsolete options to make the list less imposing.
  # This message is too long to be a string in the A/UX 3.1 sh.
  cat <<_ACEOF
-\`configure' configures sqlite 3.39.0 to adapt to many kinds of systems.
+\`configure' configures sqlite 3.39.4 to adapt to many kinds of systems.

 Usage: $0 [OPTION]... [VAR=VALUE]...

@@ -1533,7 +1533,7 @@ fi

 if test -n "$ac_init_help"; then
  case $ac_init_help in
-     short | recursive ) echo "Configuration of sqlite 3.39.0:";;
+     short | recursive ) echo "Configuration of sqlite 3.39.4:";;
   esac
  cat <<\_ACEOF

@@ -1661,7 +1661,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
  cat <<\_ACEOF
-sqlite configure 3.39.0
+sqlite configure 3.39.4
 generated by GNU Autoconf 2.69

 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -2080,7 +2080,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.

-It was created by sqlite $as_me 3.39.0, which was
+It was created by sqlite $as_me 3.39.4, which was
 generated by GNU Autoconf 2.69.  Invocation command line was

  $ $0 $@
@@ -12390,7 +12390,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by sqlite $as_me 3.39.0, which was
+This file was extended by sqlite $as_me 3.39.4, which was
 generated by GNU Autoconf 2.69.  Invocation command line was

  CONFIG_FILES    = $CONFIG_FILES
@@ -12456,7 +12456,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-sqlite config.status 3.39.0
+sqlite config.status 3.39.4
 configured by $0, generated by GNU Autoconf 2.69,
  with options \\"\$ac_cs_config\\"

@@ -0,0 +1,142 @@
+
+Shared-Schema Mode Notes
+========================
+
+The [reuse-schema](/timeline?r=reuse-schema) branch contains changes 
+to allow SQLite connections to share schemas
+between database connections within the same process in order to save memory.
+Schemas may be shared between multiple databases attached to the same or
+distinct connection handles.
+
+Compile with -DSQLITE\_ENABLE\_SHARED\_SCHEMA in order to enable the
+shared-schema enhancement.  Enabling the shared-schema enhancement causes
+approximately a 0.1% increase in CPU cycles consumed and about a 3000-byte
+increase in the size of the library, even if shared-schema is never used.
+
+Assuming the compile-time requirements are satisfied, the shared-schema
+feature is engaged by opening the database connection using the
+sqlite3&#95;open&#95;v2() API with the SQLITE&#95;OPEN&#95;SHARED&#95;SCHEMA
+flag specified.  The main database and any attached databases will then share
+an in-memory Schema object with any other database opened within the process
+for which: 
+
+  * the contents of the sqlite&#95;master table, including all object names,
+    SQL statements and root pages are identical, and
+  * have the same values for the schema-cookie.
+
+Temp databases (those populated with "CREATE TEMP TABLE" and similar
+statements) never share schemas.
+
+Connections opened with the SQLITE&#95;OPEN&#95;SHARED&#95;SCHEMA flag
+specified may not modify any database schema except that belonging to the
+temp database in anyway. This includes creating or dropping database 
+objects, vacuuming the database, or running ANALYZE when the
+sqlite&#95;stat\[14\] tables do not exist.
+
+For SQLITE&#95;OPEN&#95;SHARED&#95;SCHEMA connections, the
+SQLITE&#95;DBSTATUS&#95;SCHEMA&#95;USED sqlite3&#95;db&#95;status() verb
+distributes the memory used for a shared schema object evenly between all
+database connections that share it.
+
+## The ".shared-schema" Command
+
+The shell tool on this branch contains a special dot-command to help with
+managing databases. The ".shared-schema" dot-command can be used to test
+whether or not two databases are similar enough to share in-memory schemas,
+and to fix minor problems that prevent them from doing so. To test if
+two or more database are compatible, one database is opened directly using 
+the shell tool and the following command issued:
+
+        .shared-schema check <database-1> [<database-2>]...
+
+where &lt;database-1&gt; etc. are replaced with the names of database files
+on disk. For each database specified on the command line, a single line of
+output is produced. If the database can share an in-memory schema with the
+main database opened by the shell tool, the output is of the form:
+
+        <database> is compatible
+
+Otherwise, if the database cannot share a schema with the main db, the output
+is of the form:
+
+        <database> is NOT compatible (<reason>)
+
+where &lt;reason&gt; indicates the cause of the incompatibility. &lt;reason&gt;
+is always one of the following.
+
+<ul>
+  <li> <b>objects</b> - the databases contain a different set schema objects
+  (tables, indexes, views and triggers).
+
+  <li> <b>SQL</b> - the databases contain the same set of objects, but the SQL
+  statements used to create them were not the same.
+
+  <li> <b>root pages</b> - the databases contain the same set of objects created
+  by the same SQL statements, but the root pages are not the same.
+
+  <li> <b>order of sqlite&#95;master rows</b> - the databases contain the same
+  set of objects created by the same SQL statements with the same root pages,
+  but the order of the rows in the sqlite&#95;master tables are different.
+
+  <li> <b>schema cookie</b> - the database schemas are compatible, but the 
+  schema cookie values ("PRAGMA schema&#95;version") are different.
+</ul>
+
+The final three problems in the list above can be fixed using the
+.shared-schema command. To modify such a database so that it can share a 
+schema with the main database, the following shell command is used:
+
+        .shared-schema fix <database-1> [<database-2>]...
+
+If a database can be modified so that it may share a schema with the main
+database opened by the shell tool, output is as follows:
+
+        Fixing <database>... <database> is compatible
+
+If a database does not require modification, or cannot be modified such that
+it can share a schema with the main database, the output of "fix" is identical
+to that of the "check" command.
+
+## Implementation Notes
+
+A single Schema object is never used by more than one database simultaneously,
+regardless of whether or not those databases are attached to the same or
+different database handles. Instead, a pool of schema objects is maintained 
+for each unique sqlite&#95;master-contents/schema-cookie combination
+opened within the process. Each time database schemas are required by a
+connection, for example as part of an sqlite3&#95;prepare\*(),
+sqlite3&#95;blob&#95;open() or sqlite3&#95;blob&#95;open() call, it obtains
+the minimum number of schemas required from the various schema-pools, returning
+them at the end of the call. This means that a single schema-pool only ever
+contains more than one copy of the schema if:
+
+  * Two threads require schemas from the same pool at the same time, or
+  * A single sqlite3&#95;prepare\*() call requires schemas for two or more
+    attached databases that use the same schema-pool.
+
+The size of a schema-pool never shrinks. Each schema pool always maintains 
+a number of schema objects equal to the highwater mark of schema objects
+simultaneously required by clients.
+
+This approach is preferred to allowing multiple databases to use the same
+Schema object simultaneously for three reasons:
+
+  * The Schema object is not completely read-only. For example, the 
+    Index.zIdxAff string is allocated lazily.
+  * Throughout the statement compiler, SQLite uses variables like 
+    Table.pSchema and Index.pSchema with the sqlite3SchemaToIndex() routine
+    in order to determine which attached database a Table or Index object
+    resides in. This mechanism does not work if the same Schema may be
+    used by two or more attached databases.
+  * It may be easier to modify this approach in order to allow
+    SQLITE&#95;OPEN&#95;SHARED&#95;SCHEMA connections to modify database
+    schemas, should that be required.
+
+SQLITE&#95;OPEN&#95;SHARED&#95;SCHEMA connections do not store their
+virtual-table handles in the Table.pVTable list of each table. This would not
+work, as (a) there is no guarantee that a connection will be assigned the same
+Schema object each time it requests one from a schema-pool and (b) a single
+Schema (and therefore Table) object may correspond to tables in two or more
+databases attached to a single connection. Instead, all virtual-table handles
+associated with a single database are stored in a linked-list headed at
+Db.pVTable.
@@ -2888,7 +2888,7 @@ static int fts3TermSelectMerge(
    **
    ** Similar padding is added in the fts3DoclistOrMerge() function.
    */
-    pTS->aaOutput[0] = sqlite3_malloc(nDoclist + FTS3_VARINT_MAX + 1);
+    pTS->aaOutput[0] = sqlite3_malloc64((i64)nDoclist + FTS3_VARINT_MAX + 1);
    pTS->anOutput[0] = nDoclist;
    if( pTS->aaOutput[0] ){
      memcpy(pTS->aaOutput[0], aDoclist, nDoclist);
@@ -4308,8 +4308,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
  char *aPoslist = 0;             /* Position list for deferred tokens */
  int nPoslist = 0;               /* Number of bytes in aPoslist */
  int iPrev = -1;                 /* Token number of previous deferred token */
-
-  assert( pPhrase->doclist.bFreeList==0 );
+  char *aFree = (pPhrase->doclist.bFreeList ? pPhrase->doclist.pList : 0);

  for(iToken=0; iToken<pPhrase->nToken; iToken++){
    Fts3PhraseToken *pToken = &pPhrase->aToken[iToken];
@@ -4323,6 +4322,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){

      if( pList==0 ){
        sqlite3_free(aPoslist);
+        sqlite3_free(aFree);
        pPhrase->doclist.pList = 0;
        pPhrase->doclist.nList = 0;
        return SQLITE_OK;
@@ -4343,6 +4343,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
        nPoslist = (int)(aOut - aPoslist);
        if( nPoslist==0 ){
          sqlite3_free(aPoslist);
+          sqlite3_free(aFree);
          pPhrase->doclist.pList = 0;
          pPhrase->doclist.nList = 0;
          return SQLITE_OK;
@@ -4375,13 +4376,14 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
        nDistance = iPrev - nMaxUndeferred;
      }

-      aOut = (char *)sqlite3_malloc(nPoslist+8);
+      aOut = (char *)sqlite3Fts3MallocZero(nPoslist+FTS3_BUFFER_PADDING);
      if( !aOut ){
        sqlite3_free(aPoslist);
        return SQLITE_NOMEM;
      }
      
      pPhrase->doclist.pList = aOut;
+      assert( p1 && p2 );
      if( fts3PoslistPhraseMerge(&aOut, nDistance, 0, 1, &p1, &p2) ){
        pPhrase->doclist.bFreeList = 1;
        pPhrase->doclist.nList = (int)(aOut - pPhrase->doclist.pList);
@@ -4394,6 +4396,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
    }
  }

+  if( pPhrase->doclist.pList!=aFree ) sqlite3_free(aFree);
  return SQLITE_OK;
 }
 #endif /* SQLITE_DISABLE_FTS4_DEFERRED */
@@ -4742,7 +4745,7 @@ static int fts3EvalIncrPhraseNext(
      if( bEof==0 ){
        int nList = 0;
        int nByte = a[p->nToken-1].nList;
-        char *aDoclist = sqlite3_malloc(nByte+FTS3_BUFFER_PADDING);
+        char *aDoclist = sqlite3_malloc64((i64)nByte+FTS3_BUFFER_PADDING);
        if( !aDoclist ) return SQLITE_NOMEM;
        memcpy(aDoclist, a[p->nToken-1].pList, nByte+1);
        memset(&aDoclist[nByte], 0, FTS3_BUFFER_PADDING);
@@ -5568,11 +5571,10 @@ static int fts3EvalTestExpr(

      default: {
 #ifndef SQLITE_DISABLE_FTS4_DEFERRED
-        if( pCsr->pDeferred 
-         && (pExpr->iDocid==pCsr->iPrevId || pExpr->bDeferred)
-        ){
+        if( pCsr->pDeferred && (pExpr->bDeferred || (
+            pExpr->iDocid==pCsr->iPrevId && pExpr->pPhrase->doclist.pList
+        ))){
          Fts3Phrase *pPhrase = pExpr->pPhrase;
-          assert( pExpr->bDeferred || pPhrase->doclist.bFreeList==0 );
          if( pExpr->bDeferred ){
            fts3EvalInvalidatePoslist(pPhrase);
          }
@@ -558,7 +558,7 @@ struct Fts3MultiSegReader {
  int nAdvance;                   /* How many seg-readers to advance */
  Fts3SegFilter *pFilter;         /* Pointer to filter object */
  char *aBuffer;                  /* Buffer to merge doclists in */
-  int nBuffer;                    /* Allocated size of aBuffer[] in bytes */
+  i64 nBuffer;                    /* Allocated size of aBuffer[] in bytes */

  int iColFilter;                 /* If >=0, filter for this column */
  int bRestart;
@@ -621,7 +621,7 @@ static int porterNext(
      if( n>c->nAllocated ){
        char *pNew;
        c->nAllocated = n+20;
-        pNew = sqlite3_realloc(c->zToken, c->nAllocated);
+        pNew = sqlite3_realloc64(c->zToken, c->nAllocated);
        if( !pNew ) return SQLITE_NOMEM;
        c->zToken = pNew;
      }
@@ -185,7 +185,7 @@ static int simpleNext(
      if( n>c->nTokenAllocated ){
        char *pNew;
        c->nTokenAllocated = n+20;
-        pNew = sqlite3_realloc(c->pToken, c->nTokenAllocated);
+        pNew = sqlite3_realloc64(c->pToken, c->nTokenAllocated);
        if( !pNew ) return SQLITE_NOMEM;
        c->pToken = pNew;
      }
@@ -649,7 +649,7 @@ static int fts3PendingListAppendVarint(

  /* Allocate or grow the PendingList as required. */
  if( !p ){
-    p = sqlite3_malloc(sizeof(*p) + 100);
+    p = sqlite3_malloc64(sizeof(*p) + 100);
    if( !p ){
      return SQLITE_NOMEM;
    }
@@ -658,14 +658,14 @@ static int fts3PendingListAppendVarint(
    p->nData = 0;
  }
  else if( p->nData+FTS3_VARINT_MAX+1>p->nSpace ){
-    int nNew = p->nSpace * 2;
-    p = sqlite3_realloc(p, sizeof(*p) + nNew);
+    i64 nNew = p->nSpace * 2;
+    p = sqlite3_realloc64(p, sizeof(*p) + nNew);
    if( !p ){
      sqlite3_free(*pp);
      *pp = 0;
      return SQLITE_NOMEM;
    }
-    p->nSpace = nNew;
+    p->nSpace = (int)nNew;
    p->aData = (char *)&p[1];
  }

@@ -1222,7 +1222,7 @@ int sqlite3Fts3ReadBlock(
    int nByte = sqlite3_blob_bytes(p->pSegments);
    *pnBlob = nByte;
    if( paBlob ){
-      char *aByte = sqlite3_malloc(nByte + FTS3_NODE_PADDING);
+      char *aByte = sqlite3_malloc64((i64)nByte + FTS3_NODE_PADDING);
      if( !aByte ){
        rc = SQLITE_NOMEM;
      }else{
@@ -1339,7 +1339,7 @@ static int fts3SegReaderNext(
        int nTerm = fts3HashKeysize(pElem);
        if( (nTerm+1)>pReader->nTermAlloc ){
          sqlite3_free(pReader->zTerm);
-          pReader->zTerm = (char*)sqlite3_malloc((nTerm+1)*2);
+          pReader->zTerm = (char*)sqlite3_malloc64(((i64)nTerm+1)*2);
          if( !pReader->zTerm ) return SQLITE_NOMEM;
          pReader->nTermAlloc = (nTerm+1)*2;
        }
@@ -1347,7 +1347,7 @@ static int fts3SegReaderNext(
        pReader->zTerm[nTerm] = '\0';
        pReader->nTerm = nTerm;

-        aCopy = (char*)sqlite3_malloc(nCopy);
+        aCopy = (char*)sqlite3_malloc64(nCopy);
        if( !aCopy ) return SQLITE_NOMEM;
        memcpy(aCopy, pList->aData, nCopy);
        pReader->nNode = pReader->nDoclist = nCopy;
@@ -1634,7 +1634,7 @@ int sqlite3Fts3SegReaderNew(
    nExtra = nRoot + FTS3_NODE_PADDING;
  }

-  pReader = (Fts3SegReader *)sqlite3_malloc(sizeof(Fts3SegReader) + nExtra);
+  pReader = (Fts3SegReader *)sqlite3_malloc64(sizeof(Fts3SegReader) + nExtra);
  if( !pReader ){
    return SQLITE_NOMEM;
  }
@@ -1726,7 +1726,7 @@ int sqlite3Fts3SegReaderPending(
        if( nElem==nAlloc ){
          Fts3HashElem **aElem2;
          nAlloc += 16;
-          aElem2 = (Fts3HashElem **)sqlite3_realloc(
+          aElem2 = (Fts3HashElem **)sqlite3_realloc64(
              aElem, nAlloc*sizeof(Fts3HashElem *)
          );
          if( !aElem2 ){
@@ -2060,7 +2060,7 @@ static int fts3NodeAddTerm(
        ** this is not expected to be a serious problem. 
        */
        assert( pTree->aData==(char *)&pTree[1] );
-        pTree->aData = (char *)sqlite3_malloc(nReq);
+        pTree->aData = (char *)sqlite3_malloc64(nReq);
        if( !pTree->aData ){
          return SQLITE_NOMEM;
        }
@@ -2078,7 +2078,7 @@ static int fts3NodeAddTerm(

      if( isCopyTerm ){
        if( pTree->nMalloc<nTerm ){
-          char *zNew = sqlite3_realloc(pTree->zMalloc, nTerm*2);
+          char *zNew = sqlite3_realloc64(pTree->zMalloc, (i64)nTerm*2);
          if( !zNew ){
            return SQLITE_NOMEM;
          }
@@ -2104,7 +2104,7 @@ static int fts3NodeAddTerm(
  ** now. Instead, the term is inserted into the parent of pTree. If pTree 
  ** has no parent, one is created here.
  */
-  pNew = (SegmentNode *)sqlite3_malloc(sizeof(SegmentNode) + p->nNodeSize);
+  pNew = (SegmentNode *)sqlite3_malloc64(sizeof(SegmentNode) + p->nNodeSize);
  if( !pNew ){
    return SQLITE_NOMEM;
  }
@@ -2242,7 +2242,7 @@ static int fts3SegWriterAdd(
 ){
  int nPrefix;                    /* Size of term prefix in bytes */
  int nSuffix;                    /* Size of term suffix in bytes */
-  int nReq;                       /* Number of bytes required on leaf page */
+  i64 nReq;                       /* Number of bytes required on leaf page */
  int nData;
  SegmentWriter *pWriter = *ppWriter;

@@ -2251,13 +2251,13 @@ static int fts3SegWriterAdd(
    sqlite3_stmt *pStmt;

    /* Allocate the SegmentWriter structure */
-    pWriter = (SegmentWriter *)sqlite3_malloc(sizeof(SegmentWriter));
+    pWriter = (SegmentWriter *)sqlite3_malloc64(sizeof(SegmentWriter));
    if( !pWriter ) return SQLITE_NOMEM;
    memset(pWriter, 0, sizeof(SegmentWriter));
    *ppWriter = pWriter;

    /* Allocate a buffer in which to accumulate data */
-    pWriter->aData = (char *)sqlite3_malloc(p->nNodeSize);
+    pWriter->aData = (char *)sqlite3_malloc64(p->nNodeSize);
    if( !pWriter->aData ) return SQLITE_NOMEM;
    pWriter->nSize = p->nNodeSize;

@@ -2332,7 +2332,7 @@ static int fts3SegWriterAdd(
  ** the buffer to make it large enough.
  */
  if( nReq>pWriter->nSize ){
-    char *aNew = sqlite3_realloc(pWriter->aData, nReq);
+    char *aNew = sqlite3_realloc64(pWriter->aData, nReq);
    if( !aNew ) return SQLITE_NOMEM;
    pWriter->aData = aNew;
    pWriter->nSize = nReq;
@@ -2357,7 +2357,7 @@ static int fts3SegWriterAdd(
  */
  if( isCopyTerm ){
    if( nTerm>pWriter->nMalloc ){
-      char *zNew = sqlite3_realloc(pWriter->zMalloc, nTerm*2);
+      char *zNew = sqlite3_realloc64(pWriter->zMalloc, (i64)nTerm*2);
      if( !zNew ){
        return SQLITE_NOMEM;
      }
@@ -2665,12 +2665,12 @@ static void fts3ColumnFilter(
 static int fts3MsrBufferData(
  Fts3MultiSegReader *pMsr,       /* Multi-segment-reader handle */
  char *pList,
-  int nList
+  i64 nList
 ){
  if( nList>pMsr->nBuffer ){
    char *pNew;
    pMsr->nBuffer = nList*2;
-    pNew = (char *)sqlite3_realloc(pMsr->aBuffer, pMsr->nBuffer);
+    pNew = (char *)sqlite3_realloc64(pMsr->aBuffer, pMsr->nBuffer);
    if( !pNew ) return SQLITE_NOMEM;
    pMsr->aBuffer = pNew;
  }
@@ -2726,7 +2726,7 @@ int sqlite3Fts3MsrIncrNext(
      fts3SegReaderSort(pMsr->apSegment, nMerge, j, xCmp);

      if( nList>0 && fts3SegReaderIsPending(apSegment[0]) ){
-        rc = fts3MsrBufferData(pMsr, pList, nList+1);
+        rc = fts3MsrBufferData(pMsr, pList, (i64)nList+1);
        if( rc!=SQLITE_OK ) return rc;
        assert( (pMsr->aBuffer[nList] & 0xFE)==0x00 );
        pList = pMsr->aBuffer;
@@ -2863,11 +2863,11 @@ int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr){
  return SQLITE_OK;
 }

-static int fts3GrowSegReaderBuffer(Fts3MultiSegReader *pCsr, int nReq){
+static int fts3GrowSegReaderBuffer(Fts3MultiSegReader *pCsr, i64 nReq){
  if( nReq>pCsr->nBuffer ){
    char *aNew;
    pCsr->nBuffer = nReq*2;
-    aNew = sqlite3_realloc(pCsr->aBuffer, pCsr->nBuffer);
+    aNew = sqlite3_realloc64(pCsr->aBuffer, pCsr->nBuffer);
    if( !aNew ){
      return SQLITE_NOMEM;
    }
@@ -2958,7 +2958,8 @@ int sqlite3Fts3SegReaderStep(
    ){
      pCsr->nDoclist = apSegment[0]->nDoclist;
      if( fts3SegReaderIsPending(apSegment[0]) ){
-        rc = fts3MsrBufferData(pCsr, apSegment[0]->aDoclist, pCsr->nDoclist);
+        rc = fts3MsrBufferData(pCsr, apSegment[0]->aDoclist,
+                               (i64)pCsr->nDoclist);
        pCsr->aDoclist = pCsr->aBuffer;
      }else{
        pCsr->aDoclist = apSegment[0]->aDoclist;
@@ -3011,7 +3012,8 @@ int sqlite3Fts3SegReaderStep(

          nByte = sqlite3Fts3VarintLen(iDelta) + (isRequirePos?nList+1:0);

-          rc = fts3GrowSegReaderBuffer(pCsr, nByte+nDoclist+FTS3_NODE_PADDING);
+          rc = fts3GrowSegReaderBuffer(pCsr, 
+                                   (i64)nByte+nDoclist+FTS3_NODE_PADDING);
          if( rc ) return rc;

          if( isFirst ){
@@ -3037,7 +3039,7 @@ int sqlite3Fts3SegReaderStep(
        fts3SegReaderSort(apSegment, nMerge, j, xCmp);
      }
      if( nDoclist>0 ){
-        rc = fts3GrowSegReaderBuffer(pCsr, nDoclist+FTS3_NODE_PADDING);
+        rc = fts3GrowSegReaderBuffer(pCsr, (i64)nDoclist+FTS3_NODE_PADDING);
        if( rc ) return rc;
        memset(&pCsr->aBuffer[nDoclist], 0, FTS3_NODE_PADDING);
        pCsr->aDoclist = pCsr->aBuffer;
@@ -3750,7 +3752,7 @@ struct NodeReader {
 static void blobGrowBuffer(Blob *pBlob, int nMin, int *pRc){
  if( *pRc==SQLITE_OK && nMin>pBlob->nAlloc ){
    int nAlloc = nMin;
-    char *a = (char *)sqlite3_realloc(pBlob->a, nAlloc);
+    char *a = (char *)sqlite3_realloc64(pBlob->a, nAlloc);
    if( a ){
      pBlob->nAlloc = nAlloc;
      pBlob->a = a;
@@ -4547,7 +4549,7 @@ static int fts3RepackSegdirLevel(
      if( nIdx>=nAlloc ){
        int *aNew;
        nAlloc += 16;
-        aNew = sqlite3_realloc(aIdx, nAlloc*sizeof(int));
+        aNew = sqlite3_realloc64(aIdx, nAlloc*sizeof(int));
        if( !aNew ){
          rc = SQLITE_NOMEM;
          break;
@@ -4921,7 +4923,7 @@ int sqlite3Fts3Incrmerge(Fts3Table *p, int nMerge, int nMin){

  /* Allocate space for the cursor, filter and writer objects */
  const int nAlloc = sizeof(*pCsr) + sizeof(*pFilter) + sizeof(*pWriter);
-  pWriter = (IncrmergeWriter *)sqlite3_malloc(nAlloc);
+  pWriter = (IncrmergeWriter *)sqlite3_malloc64(nAlloc);
  if( !pWriter ) return SQLITE_NOMEM;
  pFilter = (Fts3SegFilter *)&pWriter[1];
  pCsr = (Fts3MultiSegReader *)&pFilter[1];
@@ -5557,7 +5559,7 @@ int sqlite3Fts3DeferredTokenList(
    return SQLITE_OK;
  }

-  pRet = (char *)sqlite3_malloc(p->pList->nData);
+  pRet = (char *)sqlite3_malloc64(p->pList->nData);
  if( !pRet ) return SQLITE_NOMEM;

  nSkip = sqlite3Fts3GetVarint(p->pList->aData, &dummy);
@@ -5577,7 +5579,7 @@ int sqlite3Fts3DeferToken(
  int iCol                        /* Column that token must appear in (or -1) */
 ){
  Fts3DeferredToken *pDeferred;
-  pDeferred = sqlite3_malloc(sizeof(*pDeferred));
+  pDeferred = sqlite3_malloc64(sizeof(*pDeferred));
  if( !pDeferred ){
    return SQLITE_NOMEM;
  }
@@ -16,12 +16,16 @@ source [file join [file dirname [info script]] fts5_common.tcl]
 source $testdir/malloc_common.tcl
 set testprefix fts5fault4

-# If SQLITE_ENABLE_FTS3 is defined, omit this file.
+# If SQLITE_ENABLE_FTS5 is not defined, omit this file.
 ifcapable !fts5 {
  finish_test
  return
 }

+set ::TMPDBERROR [list 1 \
+  {unable to open a temporary database file for storing temporary tables}
+]
+
 #-------------------------------------------------------------------------
 # An OOM while dropping an fts5 table.
 #
@@ -391,7 +395,7 @@ do_faultsim_test 14.1 -faults oom-t* -prep {
 } -body {
  db eval { ALTER TABLE "tbl one" RENAME TO "tbl two" }
 } -test {
-  faultsim_test_result {0 {}}
+  faultsim_test_result {0 {}} $::TMPDBERROR
 }

 finish_test
@@ -299,8 +299,9 @@ static void icuRegexpFunc(sqlite3_context *p, int nArg, sqlite3_value **apArg){

    if( U_SUCCESS(status) ){
      sqlite3_set_auxdata(p, 0, pExpr, icuRegexpDelete);
-    }else{
-      assert(!pExpr);
+      pExpr = sqlite3_get_auxdata(p, 0);
+    }
+    if( !pExpr ){
      icuFunctionError(p, "uregex_open", status);
      return;
    }
@@ -685,7 +685,7 @@ static const char *re_compile(ReCompiled **ppRe, const char *zIn, int noCase){
        pRe->zInit[j++] = (unsigned char)(0xc0 | (x>>6));
        pRe->zInit[j++] = 0x80 | (x&0x3f);
      }else if( x<=0xffff ){
-        pRe->zInit[j++] = (unsigned char)(0xd0 | (x>>12));
+        pRe->zInit[j++] = (unsigned char)(0xe0 | (x>>12));
        pRe->zInit[j++] = 0x80 | ((x>>6)&0x3f);
        pRe->zInit[j++] = 0x80 | (x&0x3f);
      }else{
@@ -30,6 +30,16 @@ SQLITE_EXTENSION_INIT1

 #ifndef SQLITE_OMIT_VIRTUALTABLE

+
+#define STMT_NUM_INTEGER_COLUMN 10
+typedef struct StmtRow StmtRow;
+struct StmtRow {
+  sqlite3_int64 iRowid;                /* Rowid value */
+  char *zSql;                          /* column "sql" */
+  int aCol[STMT_NUM_INTEGER_COLUMN+1]; /* all other column values */
+  StmtRow *pNext;                      /* Next row to return */
+};
+
 /* stmt_vtab is a subclass of sqlite3_vtab which will
 ** serve as the underlying representation of a stmt virtual table
 */
@@ -47,8 +57,7 @@ typedef struct stmt_cursor stmt_cursor;
 struct stmt_cursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  sqlite3 *db;               /* Database connection for this cursor */
-  sqlite3_stmt *pStmt;       /* Statement cursor is currently pointing at */
-  sqlite3_int64 iRowid;      /* The rowid */
+  StmtRow *pRow;             /* Current row */
 };

 /*
@@ -92,7 +101,7 @@ static int stmtConnect(
     "CREATE TABLE x(sql,ncol,ro,busy,nscan,nsort,naidx,nstep,"
                    "reprep,run,mem)");
  if( rc==SQLITE_OK ){
-    pNew = sqlite3_malloc( sizeof(*pNew) );
+    pNew = sqlite3_malloc64( sizeof(*pNew) );
    *ppVtab = (sqlite3_vtab*)pNew;
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(*pNew));
@@ -114,7 +123,7 @@ static int stmtDisconnect(sqlite3_vtab *pVtab){
 */
 static int stmtOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  stmt_cursor *pCur;
-  pCur = sqlite3_malloc( sizeof(*pCur) );
+  pCur = sqlite3_malloc64( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  pCur->db = ((stmt_vtab*)p)->db;
@@ -122,10 +131,21 @@ static int stmtOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  return SQLITE_OK;
 }

+static void stmtCsrReset(stmt_cursor *pCur){
+  StmtRow *pRow = 0;
+  StmtRow *pNext = 0;
+  for(pRow=pCur->pRow; pRow; pRow=pNext){
+    pNext = pRow->pNext;
+    sqlite3_free(pRow);
+  }
+  pCur->pRow = 0;
+}
+
 /*
 ** Destructor for a stmt_cursor.
 */
 static int stmtClose(sqlite3_vtab_cursor *cur){
+  stmtCsrReset((stmt_cursor*)cur);
  sqlite3_free(cur);
  return SQLITE_OK;
 }
@@ -136,8 +156,9 @@ static int stmtClose(sqlite3_vtab_cursor *cur){
 */
 static int stmtNext(sqlite3_vtab_cursor *cur){
  stmt_cursor *pCur = (stmt_cursor*)cur;
-  pCur->iRowid++;
-  pCur->pStmt = sqlite3_next_stmt(pCur->db, pCur->pStmt);
+  StmtRow *pNext = pCur->pRow->pNext;
+  sqlite3_free(pCur->pRow);
+  pCur->pRow = pNext;
  return SQLITE_OK;
 }

@@ -151,39 +172,11 @@ static int stmtColumn(
  int i                       /* Which column to return */
 ){
  stmt_cursor *pCur = (stmt_cursor*)cur;
-  switch( i ){
-    case STMT_COLUMN_SQL: {
-      sqlite3_result_text(ctx, sqlite3_sql(pCur->pStmt), -1, SQLITE_TRANSIENT);
-      break;
-    }
-    case STMT_COLUMN_NCOL: {
-      sqlite3_result_int(ctx, sqlite3_column_count(pCur->pStmt));
-      break;
-    }
-    case STMT_COLUMN_RO: {
-      sqlite3_result_int(ctx, sqlite3_stmt_readonly(pCur->pStmt));
-      break;
-    }
-    case STMT_COLUMN_BUSY: {
-      sqlite3_result_int(ctx, sqlite3_stmt_busy(pCur->pStmt));
-      break;
-    }
-    default: {
-      assert( i==STMT_COLUMN_MEM );
-      i = SQLITE_STMTSTATUS_MEMUSED + 
-            STMT_COLUMN_NSCAN - SQLITE_STMTSTATUS_FULLSCAN_STEP;
-      /* Fall thru */
-    }
-    case STMT_COLUMN_NSCAN:
-    case STMT_COLUMN_NSORT:
-    case STMT_COLUMN_NAIDX:
-    case STMT_COLUMN_NSTEP:
-    case STMT_COLUMN_REPREP:
-    case STMT_COLUMN_RUN: {
-      sqlite3_result_int(ctx, sqlite3_stmt_status(pCur->pStmt,
-                      i-STMT_COLUMN_NSCAN+SQLITE_STMTSTATUS_FULLSCAN_STEP, 0));
-      break;
-    }
+  StmtRow *pRow = pCur->pRow;
+  if( i==STMT_COLUMN_SQL ){
+    sqlite3_result_text(ctx, pRow->zSql, -1, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_int(ctx, pRow->aCol[i]);
  }
  return SQLITE_OK;
 }
@@ -194,7 +187,7 @@ static int stmtColumn(
 */
 static int stmtRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  stmt_cursor *pCur = (stmt_cursor*)cur;
-  *pRowid = pCur->iRowid;
+  *pRowid = pCur->pRow->iRowid;
  return SQLITE_OK;
 }

@@ -204,7 +197,7 @@ static int stmtRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
 */
 static int stmtEof(sqlite3_vtab_cursor *cur){
  stmt_cursor *pCur = (stmt_cursor*)cur;
-  return pCur->pStmt==0;
+  return pCur->pRow==0;
 }

 /*
@@ -219,9 +212,53 @@ static int stmtFilter(
  int argc, sqlite3_value **argv
 ){
  stmt_cursor *pCur = (stmt_cursor *)pVtabCursor;
-  pCur->pStmt = 0;
-  pCur->iRowid = 0;
-  return stmtNext(pVtabCursor);
+  sqlite3_stmt *p = 0;
+  sqlite3_int64 iRowid = 1;
+  StmtRow **ppRow = 0;
+
+  stmtCsrReset(pCur);
+  ppRow = &pCur->pRow;
+  for(p=sqlite3_next_stmt(pCur->db, 0); p; p=sqlite3_next_stmt(pCur->db, p)){
+    const char *zSql = sqlite3_sql(p);
+    sqlite3_int64 nSql = zSql ? strlen(zSql)+1 : 0;
+    StmtRow *pNew = (StmtRow*)sqlite3_malloc64(sizeof(StmtRow) + nSql);
+
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(StmtRow));
+    if( zSql ){
+      pNew->zSql = (char*)&pNew[1];
+      memcpy(pNew->zSql, zSql, nSql);
+    }
+    pNew->aCol[STMT_COLUMN_NCOL] = sqlite3_column_count(p);
+    pNew->aCol[STMT_COLUMN_RO] = sqlite3_stmt_readonly(p);
+    pNew->aCol[STMT_COLUMN_BUSY] = sqlite3_stmt_busy(p);
+    pNew->aCol[STMT_COLUMN_NSCAN] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_FULLSCAN_STEP, 0
+    );
+    pNew->aCol[STMT_COLUMN_NSORT] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_SORT, 0
+    );
+    pNew->aCol[STMT_COLUMN_NAIDX] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_AUTOINDEX, 0
+    );
+    pNew->aCol[STMT_COLUMN_NSTEP] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_VM_STEP, 0
+    );
+    pNew->aCol[STMT_COLUMN_REPREP] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_REPREPARE, 0
+    );
+    pNew->aCol[STMT_COLUMN_RUN] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_RUN, 0
+    );
+    pNew->aCol[STMT_COLUMN_MEM] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_MEMUSED, 0
+    );
+    pNew->iRowid = iRowid++;
+    *ppRow = pNew;
+    ppRow = &pNew->pNext;
+  }
+
+  return SQLITE_OK;
 }

 /*
@@ -1695,7 +1695,7 @@ static int geopolyUpdate(
      sqlite3_free(p);
      nChange = 1;
    }
-    for(jj=1; jj<pRtree->nAux; jj++){
+    for(jj=1; jj<nData-2; jj++){
      nChange++;
      sqlite3_bind_value(pUp, jj+2, aData[jj+2]);
    }
@@ -23,6 +23,10 @@ ifcapable !rtree {
  return
 }

+set ::TMPDBERROR [list 1 \
+  {unable to open a temporary database file for storing temporary tables}
+]
+
 # Test summary:
 #
 #   rtree3-1: Test OOM in simple CREATE TABLE, INSERT, DELETE and SELECT 
@@ -196,9 +200,9 @@ do_test rtree3-7.prep {
 do_faultsim_test rtree3-7 -faults oom-* -prep {
  faultsim_restore_and_reopen
 } -body {
-  execsql { ALTER TABLE rt RENAME TO rt2 }
+  execsql { ALTER TABLE rt RENAME TO rt2 } 
 } -test {
-  faultsim_test_result {0 {}}
+  faultsim_test_result {0 {}} $::TMPDBERROR
 }

 do_faultsim_test rtree3-8 -faults oom-* -prep {
@@ -344,6 +344,7 @@ TESTSRC = \
  $(TOP)/src/test_quota.c \
  $(TOP)/src/test_rtree.c \
  $(TOP)/src/test_schema.c \
+  $(TOP)/src/test_schemapool.c \
  $(TOP)/src/test_server.c \
  $(TOP)/src/test_sqllog.c \
  $(TOP)/src/test_superlock.c \
@@ -400,6 +401,7 @@ TESTSRC2 = \
  $(TOP)/src/backup.c \
  $(TOP)/src/btree.c \
  $(TOP)/src/build.c \
+  $(TOP)/src/callback.c \
  $(TOP)/src/date.c \
  $(TOP)/src/dbpage.c \
  $(TOP)/src/dbstat.c \
@@ -423,6 +425,7 @@ TESTSRC2 = \
  $(TOP)/src/select.c \
  $(TOP)/src/threads.c \
  $(TOP)/src/tokenize.c \
+  $(TOP)/src/treeview.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vdbeapi.c \
@@ -1,13 +1,13 @@
-C Version\s3.39.0
-D 2022-06-25T14:57:57.276
+C Merge\sversion\s3.39.4\schanges\sinto\sthe\sreuse-schema-3.39\sbranch.
+D 2022-09-30T12:27:46.631
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
-F Makefile.in bccb0ed3f05fc41aee15da77c844c48b5da419cbb9af35b8a147536c9ad1c822
+F Makefile.in 9c3b2a19a0695008e177b61f903a67ad6109da2ace2a906b50f8f517a46802d1
 F Makefile.linux-gcc f609543700659711fbd230eced1f01353117621dccae7b9fb70daa64236c5241
-F Makefile.msc de7cb3e095ce2fdc33513ccd76ebdaeda1483d0ddab0410fe65cbdeadd4c0ee1
+F Makefile.msc 73a85e1c9858209075fe6d4efadb2201ac147ee995733752c3e2432d747b2977
 F README.md 8b8df9ca852aeac4864eb1e400002633ee6db84065bd01b78c33817f97d31f5e
-F VERSION fa8e7d2d1cc962f9e14c6d410387cf75860ee139462763fda887c1be4261f824
+F VERSION ad74f073c8910c112b5db75d9a7be486305a91d8a352d53f2a4c7dda9e9e5efa
 F aclocal.m4 a5c22d164aff7ed549d53a90fa56d56955281f50
 F art/sqlite370.eps aa97a671332b432a54e1d74ff5e8775be34200c2
 F art/sqlite370.ico af56c1d00fee7cd4753e8631ed60703ed0fc6e90
@@ -34,13 +34,14 @@ F autoconf/tea/win/rules.vc c511f222b80064096b705dbeb97060ee1d6b6d63
 F config.guess 883205ddf25b46f10c181818bf42c09da9888884af96f79e1719264345053bd6
 F config.h.in 6376abec766e9a0785178b1823b5a587e9f1ccbc
 F config.sub c2d0260f17f3e4bc0b6808fccf1b291cb5e9126c14fc5890efc77b9fd0175559
-F configure 00378d14cca0ce02fa9eca28fd494789c2eda7d10d86003a5f9a42f34b0af418 x
+F configure 01ce1a8ad8aa8450bc4e7bef937588a116ed724aa49802537ec9399ee18a8488 x
 F configure.ac 3ef6eeff4387585bfcab76b0c3f6e15a0618587bb90245dd5d44e4378141bb35
 F contrib/sqlitecon.tcl 210a913ad63f9f991070821e599d600bd913e0ad
 F doc/F2FS.txt c1d4a0ae9711cfe0e1d8b019d154f1c29e0d3abfe820787ba1e9ed7691160fcd
 F doc/json-enhancements.md e356fc834781f1f1aa22ee300027a270b2c960122468499bf347bb123ce1ea4f
 F doc/lemon.html efc0cd2345d66905505d98f862e1c571512def0ceb5b016cb658fd4918eb76a3
 F doc/pager-invariants.txt 27fed9a70ddad2088750c4a2b493b63853da2710
+F doc/shared_schema.md 759fc374709fccf4e5d2d0cbd05f8fedd38fb022bdd8a6c5b5f492684c7023b9
 F doc/trusted-schema.md 33625008620e879c7bcfbbfa079587612c434fa094d338b08242288d358c3e8a
 F doc/vdbesort-memory.md 4da2639c14cd24a31e0af694b1a8dd37eaf277aff3867e9a8cc14046bc49df56
 F doc/vfs-shm.txt e101f27ea02a8387ce46a05be2b1a902a021d37a
@@ -102,25 +103,25 @@ F ext/fts3/README.content b9078d0843a094d86af0d48dffbff13c906702b4c3558012e67b9c
 F ext/fts3/README.syntax a19711dc5458c20734b8e485e75fb1981ec2427a
 F ext/fts3/README.tokenizers b92bdeb8b46503f0dd301d364efc5ef59ef9fa8e2758b8e742f39fa93a2e422d
 F ext/fts3/README.txt 8c18f41574404623b76917b9da66fcb0ab38328d
-F ext/fts3/fts3.c 6634a3854e70afa8710ee5e3a7253cd0f0c89d4cce207fcbfe2ead3bad1db7d5
+F ext/fts3/fts3.c 46c116ee0868fc09520d61a1b747c62343c71c399ba67a3d0395b0be29b1a19f
 F ext/fts3/fts3.h 3a10a0af180d502cecc50df77b1b22df142817fe
-F ext/fts3/fts3Int.h dafdc371f9fbab175744b06cfe019d5f040cdfdbd11fea752f5dc28d45b04c05
+F ext/fts3/fts3Int.h ae2a44b04cddb5fb35cac4ea5f7f819b2894fd258186465777a19f7acfdf84ed
 F ext/fts3/fts3_aux.c f0dc9bd98582615b7750218899bd0c729879b6bbf94d1be57ca1833ff49afc6f
 F ext/fts3/fts3_expr.c 903bfb9433109fffb10e910d7066c49cbf8eeae316adc93f0499c4da7dfc932a
 F ext/fts3/fts3_hash.c 8b6e31bfb0844c27dc6092c2620bdb1fca17ed613072db057d96952c6bdb48b7
 F ext/fts3/fts3_hash.h 39cf6874dc239d6b4e30479b1975fe5b22a3caaf
 F ext/fts3/fts3_icu.c 305ce7fb6036484085b5556a9c8e62acdc7763f0f4cdf5fd538212a9f3720116
-F ext/fts3/fts3_porter.c 3565faf04b626cddf85f03825e86056a4562c009
+F ext/fts3/fts3_porter.c e19807ce0ae31c1c6e9898e89ecc93183d7ec224ea101af039722a4f49e5f2b8
 F ext/fts3/fts3_snippet.c f9a8149173553113f3c495a503843e30028b5dc3723d0ca798c5ad6142e130e6
 F ext/fts3/fts3_term.c f45a1e7c6ef464abb1231245d123dae12266b69e05cc56e14045b76591ae92d1
 F ext/fts3/fts3_test.c d8d7b2734f894e8a489987447658e374cdd3a3bc8575c401decf1911cb7c6454
 F ext/fts3/fts3_tokenize_vtab.c a95feda3590f3c3e17672fe35b67ea6112471aeea4c07ef7744a6606b66549aa
 F ext/fts3/fts3_tokenizer.c 6d8fc150c48238955d5182bf661498db0dd473c8a2a80e00c16994a646fa96e7
 F ext/fts3/fts3_tokenizer.h 64c6ef6c5272c51ebe60fc607a896e84288fcbc3
-F ext/fts3/fts3_tokenizer1.c 5c98225a53705e5ee34824087478cf477bdb7004
+F ext/fts3/fts3_tokenizer1.c c1de4ae28356ad98ccb8b2e3388a7fdcce7607b5523738c9afb6275dab765154
 F ext/fts3/fts3_unicode.c de426ff05c1c2e7bce161cf6b706638419c3a1d9c2667de9cb9dc0458c18e226
 F ext/fts3/fts3_unicode2.c 416eb7e1e81142703520d284b768ca2751d40e31fa912cae24ba74860532bf0f
-F ext/fts3/fts3_write.c 85279b980f99253c296006503a13f92957ec49b716123083f021acc74545ecfc
+F ext/fts3/fts3_write.c 4fb644df0ff840267e47a724286c7a1fa5540273a7ce15756dd5913a101ec302
 F ext/fts3/fts3speed.tcl b54caf6a18d38174f1a6e84219950d85e98bb1e9
 F ext/fts3/tool/fts3cov.sh c331d006359456cf6f8f953e37f2b9c7d568f3863f00bb5f7eb87fea4ac01b73
 F ext/fts3/tool/fts3view.c 413c346399159df81f86c4928b7c4a455caab73bfbc8cd68f950f632e5751674
@@ -191,7 +192,7 @@ F ext/fts5/test/fts5eb.test a973baadac524dbbb4ad9b0e99030e12cabde2c6b28e0ac43729
 F ext/fts5/test/fts5fault1.test d28a65caee75db6897c3cf1358c5230d3bb2a3bf7fb31062c19c7e5382b3d2bd
 F ext/fts5/test/fts5fault2.test 69c8fdbef830cd0d450908d4504d5bb86609e255af99c421c20a0756251fe344
 F ext/fts5/test/fts5fault3.test da2f9e3e56ff5740d68ebdd6877c97089e7ed28ddff28a0da87a6afea27e5522
-F ext/fts5/test/fts5fault4.test 1c1db5fcfe59401e7833146100f1d8de284a0a686fac31ddac9fb56c459f725b
+F ext/fts5/test/fts5fault4.test 87a10d0caee57da587c7588b0c8d25d2930197399b4812ad1e4d574c75324cee
 F ext/fts5/test/fts5fault5.test a336e4e11847de24c9497f80cce18e00bb3fab7fb11f97d04eb9af898900a762
 F ext/fts5/test/fts5fault6.test a0fc0a8f99e4b16500c31dfc7e38e1defe0f1693ac47650517ac7b723b1956f8
 F ext/fts5/test/fts5fault7.test 0acbec416edb24b8881f154e99c31e9ccf73f539cfcd164090be139e9e97ed4c
@@ -255,7 +256,7 @@ F ext/fts5/tool/loadfts5.tcl 95b03429ee6b138645703c6ca192c3ac96eaf093
 F ext/fts5/tool/mkfts5c.tcl 3eba8e9bee4221ed165f3304b51b2a74a705f4ec5df3d044573a2be539534af8
 F ext/fts5/tool/showfts5.tcl d54da0e067306663e2d5d523965ca487698e722c
 F ext/icu/README.txt 7ab7ced8ae78e3a645b57e78570ff589d4c672b71370f5aa9e1cd7024f400fc9
-F ext/icu/icu.c 91c021c7e3e8bbba286960810fa303295c622e323567b2e6def4ce58e4466e60
+F ext/icu/icu.c c074519b46baa484bb5396c7e01e051034da8884bad1a1cb7f09bbe6be3f0282
 F ext/icu/sqliteicu.h fa373836ed5a1ee7478bdf8a1650689294e41d0c89c1daab26e9ae78a32075a8
 F ext/lsm1/Makefile a553b728bba6c11201b795188c5708915cc4290f02b7df6ba7e8c4c943fd5cd9
 F ext/lsm1/Makefile.msc f8c878b467232226de288da320e1ac71c131f5ec91e08b21f502303347260013
@@ -334,7 +335,7 @@ F ext/misc/normalize.c bd84355c118e297522aba74de34a4fd286fc775524e0499b14473918d
 F ext/misc/percentile.c b9086e223d583bdaf8cb73c98a6539d501a2fc4282654adbfea576453d82e691
 F ext/misc/prefixes.c 0f4f8cff5aebc00a7e3ac4021fd59cfe1a8e17c800ceaf592859ecb9cbc38196
 F ext/misc/qpvtab.c 09738419e25f603a35c0ac8bd0a04daab794f48d08a9bc07a6085b9057b99009
-F ext/misc/regexp.c b267fd05ff8d38b22f4c2809d7b7a2c61d522e9faf2feb928dbb9662e4a3a386
+F ext/misc/regexp.c 03e483711534c437b2e29648d2a4b7730f5cb781a434ac8150907376bc4489f6
 F ext/misc/remember.c add730f0f7e7436cd15ea3fd6a90fd83c3f706ab44169f7f048438b7d6baa69c
 F ext/misc/rot13.c 51ac5f51e9d5fd811db58a9c23c628ad5f333c173f1fc53c8491a3603d38556c
 F ext/misc/scrub.c 2a44b0d44c69584c0580ad2553f6290a307a49df4668941d2812135bfb96a946
@@ -344,7 +345,7 @@ F ext/misc/shathree.c 7b17615869a495659f1569ada1d8d3d21b4a24614f2746d93cc87ef7c0
 F ext/misc/showauth.c 732578f0fe4ce42d577e1c86dc89dd14a006ab52
 F ext/misc/spellfix.c 94df9bbfa514a563c1484f684a2df3d128a2f7209a84ca3ca100c68a0163e29f
 F ext/misc/sqlar.c 0ace5d3c10fe736dc584bf1159a36b8e2e60fab309d310cd8a0eecd9036621b6
-F ext/misc/stmt.c 35063044a388ead95557e4b84b89c1b93accc2f1c6ddea3f9710e8486a7af94a
+F ext/misc/stmt.c ed05ad78013edccd43f4fc33d8244001f6f886eb2dfd2106ba33616ac514c6fb
 F ext/misc/templatevtab.c 8a16a91a5ceaccfcbd6aaaa56d46828806e460dd194965b3f77bf38f14b942c4
 F ext/misc/totype.c fa4aedeb07f66169005dffa8de3b0a2b621779fd44f85c103228a42afa71853b
 F ext/misc/uint.c 053fed3bce2e89583afcd4bf804d75d659879bbcedac74d0fa9ed548839a030b
@@ -413,12 +414,12 @@ F ext/repair/test/checkfreelist01.test 3e8aa6aeb4007680c94a8d07b41c339aa635cc782
 F ext/repair/test/checkindex01.test b530f141413b587c9eb78ff734de6bb79bc3515c335096108c12c01bddbadcec
 F ext/repair/test/test.tcl 686d76d888dffd021f64260abf29a55c57b2cedfa7fc69150b42b1d6119aac3c
 F ext/rtree/README 6315c0d73ebf0ec40dedb5aa0e942bc8b54e3761
-F ext/rtree/geopoly.c cc3f89c11abcf114fa60d74709ae8b5bc1eae5a261b30bc1bb7085089c03bfab
+F ext/rtree/geopoly.c bb0dcd013dbb3fe0335b6bbae0d9c29fcfffda93d5ef6c31daa47e802132e435
 F ext/rtree/rtree.c d7b4b8b81d8d54376a7f81de5be85ec58b37c11604bcf42984a8418b34158d93
 F ext/rtree/rtree.h 4a690463901cb5e6127cf05eb8e642f127012fd5003830dbc974eca5802d9412
 F ext/rtree/rtree1.test d47f58832145fcfed9067bc457ca8664962196c4566c17a1ebd679367db55d11
 F ext/rtree/rtree2.test 9d9deddbb16fd0c30c36e6b4fdc3ee3132d765567f0f9432ee71e1303d32603d
-F ext/rtree/rtree3.test 4ee5d7df86040efe3d8d84f141f2962a7745452200a7cba1db06f86d97050499
+F ext/rtree/rtree3.test 272594f88c344e973864008bbe4c71fd3a41a264c097d568593ee7886d83d409
 F ext/rtree/rtree4.test 304de65d484540111b896827e4261815e5dca4ce28eeecd58be648cd73452c4b
 F ext/rtree/rtree5.test 49c9041d713d54560b315c2c7ef7207ee287eba1b20f8266968a06f2e55d3142
 F ext/rtree/rtree6.test 9ce3691c1aac43070a9f194f0ebf54372db346c5a82241fd11b525ed53ce9f3f
@@ -491,7 +492,7 @@ F ext/userauth/userauth.c 7f00cded7dcaa5d47f54539b290a43d2e59f4b1eb5f447545fa865
 F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895 x
 F ltmain.sh 3ff0879076df340d2e23ae905484d8c15d5fdea8
 F magic.txt 8273bf49ba3b0c8559cb2774495390c31fd61c60
-F main.mk a5412510e5ec952915a7fda34e02079bb4e6ff8f97903f2a3d9ad2dee3e18044
+F main.mk 556c8cb7074f4f24ecd5d9fcd9e718f54e2a9c40ffe22a7d265424a28e336b59
 F mkso.sh fd21c06b063bb16a5d25deea1752c2da6ac3ed83
 F mptest/config01.test 3c6adcbc50b991866855f1977ff172eb6d901271
 F mptest/config02.test 4415dfe36c48785f751e16e32c20b077c28ae504
@@ -503,20 +504,20 @@ F spec.template 86a4a43b99ebb3e75e6b9a735d5fd293a24e90ca
 F sqlite.pc.in 42b7bf0d02e08b9e77734a47798d1a55a9e0716b
 F sqlite3.1 fc7ad8990fc8409983309bb80de8c811a7506786
 F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
-F src/alter.c 0390ca1d69ec3626cfa9f153114b7ab233e6b2bada6a9eb91361ed385fe90deb
-F src/analyze.c aabdf3769c7fd9954a8ec508eb7041ae174b66f88d12c47199fabbea9a646467
-F src/attach.c 4431f82f0247bf3aaf91589acafdff77d1882235c95407b36da1585c765fbbc8
+F src/alter.c 23f95fd33885c27edb5ece2bec9c184d3c7e575a3de60a97c036aa9d225e06f4
+F src/analyze.c ac1decb7db9f8fc12ad930d35b44f06d4097643b52dc9264ae18f8eca5c25f0d
+F src/attach.c e1eb237a21422b2d637fd854e1b72609b1b589e24b4b3a5cac0e13c9ef20ee8d
 F src/auth.c f4fa91b6a90bbc8e0d0f738aa284551739c9543a367071f55574681e0f24f8cf
 F src/backup.c a2891172438e385fdbe97c11c9745676bec54f518d4447090af97189fd8e52d7
 F src/bitvec.c 7c849aac407230278445cb069bebc5f89bf2ddd87c5ed9459b070a9175707b3d
 F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
-F src/btree.c b5a74c39d3123dadd190019c0afadd7f62b43dfe0712a39e9d0ff2fe26be5d93
+F src/btree.c 98e30d582239e1c940390f6487aa0d231691989a142fa863a689c021517ede08
 F src/btree.h 74d64b8f28cfa4a894d14d4ed64fa432cd697b98b61708d4351482ae15913e22
 F src/btreeInt.h 8ce1332edd89dfd2461d561ac10a0ab5601c8e06200cb5230596c3caaf54482e
-F src/build.c 23f874642825d7eaaeeb7a3281b2b1a75e1d4c4dd9ae4dceddcd908266634214
-F src/callback.c 4c19af69835787bfe790ac560f3071a824eb629f34e41f97b52ce5235c77de1c
+F src/build.c e54898c7e04c50f67699829f3d7674cf81ed8166bcf163612db01ff6b31759aa
+F src/callback.c f733593c95ed7ab24e0a0f57db6755b9bd433862d187766ec9f161ef7c79efeb
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
-F src/ctime.c 026dbdcdbd8c3cde98a88483ee88310ff43150ab164ad768f12cc700a11495ad
+F src/ctime.c 53d64b59d7cfa1a1f01ae81d7f7115014d7d89f3c544079d08f6b159af2fb848
 F src/date.c 15082566229d4b1e5f24fdb490bf9bcc68824b911d70e3573ef075a1b9e2d26f
 F src/dbpage.c 90661a87e1db8bfbc8d2ebbdcd3749651ddb287c555c07a28fb17c7c591ffb68
 F src/dbstat.c 861e08690fcb0f2ee1165eff0060ea8d4f3e2ea10f80dab7d32ad70443a6ff2d
@@ -534,8 +535,8 @@ F src/insert.c 173845e5a6bac96ae937409e4f876b631f26b31dabb9df8fd0eb3b130b2bb3a7
 F src/json.c 7749b98c62f691697c7ee536b570c744c0583cab4a89200fdd0fc2aa8cc8cbd6
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 853385cc7a604157e137585097949252d5d0c731768e16b044608e5c95c3614b
-F src/main.c e946f1d9e30bf49cf399ddf860cfd2319e3a97bbaabfb8e87d6ab985a20d54ad
-F src/malloc.c a9127efdcef92d6934c6339ea9813075b90edc0ce2e5c723556381a3828fb720
+F src/main.c 0033f65efa7d3431546170a1a6c8f7878861194222877e57b7518021c1c27e58
+F src/malloc.c 4a3785323104678a8b4b0a482fe0c2a80900e7468ddf76ab0f2ea1c79a8ca8cd
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c c12a42539b1ba105e3707d0e628ad70e611040d8f5e38cf942cee30c867083de
 F src/mem2.c c8bfc9446fd0798bddd495eb5d9dbafa7d4b7287d8c22d50a83ac9daa26d8a75
@@ -554,32 +555,32 @@ F src/os.c b1c4f2d485961e9a5b6b648c36687d25047c252222e9660b7cc25a6e1ea436ab
 F src/os.h 1ff5ae51d339d0e30d8a9d814f4b8f8e448169304d83a7ed9db66a65732f3e63
 F src/os_common.h b2f4707a603e36811d9b1a13278bffd757857b85
 F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586
-F src/os_unix.c 2df2b33db88f00af13805d4573ee126bc5973f9e3b91d03c575fa7ba64e7dc41
-F src/os_win.c a8ea80037e81127ca01959daa87387cc135f325c88dc745376c4f760de852a10
+F src/os_unix.c e020676e334a0a78c3affb7dd1789a240071ed6af98309f1bef76948cb8382bd
+F src/os_win.c e9454cb141908e8eef2102180bad353a36480612d5b736e4c2bd5777d9b25a34
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
-F src/pager.c 74596fc3d5d8a50de32c37225fc300cccd5ea27ea303c5f4b845d6572f999c5f
+F src/pager.c 8c3853cad320c24904a2f970777bbdda2deb9572f53e6a1d73b28b85a7fd30cc
 F src/pager.h f82e9844166e1585f5786837ddc7709966138ced17f568c16af7ccf946c2baa3
 F src/parse.y 8e67d820030d2655b9942ffe61c1e7e6b96cea2f2f72183533299393907d0564
-F src/pcache.c 084e638432c610f95aea72b8509f0845d2791293f39d1b82f0c0a7e089c3bb6b
+F src/pcache.c 5df59c993907b742dfac6aa9038d2515856bede56040a7640d39d06e1c93b494
 F src/pcache.h 4f87acd914cef5016fae3030343540d75f5b85a1877eed1a2a19b9f284248586
-F src/pcache1.c 54881292a9a5db202b2c0ac541c5e3ef9a5e8c4f1c1383adb2601d5499a60e65
-F src/pragma.c d1aead03e8418ff586c7cfca344c50a914b8eb06abd841e8e91a982d823671da
-F src/pragma.h e690a356c18e98414d2e870ea791c1be1545a714ba623719deb63f7f226d8bb7
-F src/prepare.c c62820c15dcb63013519c8e41d9f928d7478672cc902cfd0581c733c271dbf45
-F src/printf.c 6166a30417b05c5b2f82e1f183f75faa2926ad60531c0b688a57dbc951441a20
+F src/pcache1.c 3e6267b17bae4cbaf02dfa08c4507794452991206862e3fc5c94d28313d32c18
+F src/pragma.c 395a1d0912218e6bd67d0cc58b9317540f74da8b7f1e370150a495f0fdbe05ef
+F src/pragma.h 50f6d3b408ed56bde4f4e4aead8c0b2022030b692e8de237c1b7a0b5ce87a0c8
+F src/prepare.c d91f59db086b7b738ada7f06c1c09e151a40ca219565d1937da3968b299166e6
+F src/printf.c e99ee9741e79ae3873458146f59644276657340385ade4e76a5f5d1c25793764
 F src/random.c 097dc8b31b8fba5a9aca1697aeb9fd82078ec91be734c16bffda620ced7ab83c
-F src/resolve.c 1655e44c77c51ebbe82924287528a78bd4a4aaaf34189dbae28d19ccf2ca615c
+F src/resolve.c f0d663c9b1ceeb3e7d262ede872dd3b24b323a7cc11d84c05a39d962e7d64b07
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c 2db8bbf13f57cc9872f9b927546e98f5ea583e9e364182426492a434a994421b
-F src/shell.c.in 08e59f1cb9d9b1180aba52861aaada0c95f6ddd210488719684e160a0724c806
-F src/sqlite.h.in 172528c287399a34f188154017b7268bf82c6d5b780902e361958d2318c4e37c
+F src/select.c fea5ae26259dc995b2144a28bbb5b013196dbcc86527cd992ed109b00af7f9e8
+F src/shell.c.in d92bc2b81afab457b82297c7405a9388a5ae1d792b5e90ebdf589d05987d0be2
+F src/sqlite.h.in fab3ab25167b24762a27dbef9e49cbe469963f80dec6e22398c33f2c7ec73aca
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h a988810c9b21c0dc36dc7a62735012339dc76fc7ab448fb0792721d30eacb69d
-F src/sqliteInt.h 8353e96646372efdb0795a13cd9949831b4992c928de8f5c43b2524e8a4c6e7b
+F src/sqliteInt.h e938d47c077c8ef50caa3aa212ec32680451b7d31cc9623612e61d3f0d176fed
 F src/sqliteLimit.h d7323ffea5208c6af2734574bae933ca8ed2ab728083caa117c9738581a31657
-F src/status.c 4a3da6d77eeb3531cb0dbdf7047772a2a1b99f98c69e90ce009c75fe6328b2c0
+F src/status.c 99fd56b274f5d4b79b5af65a92ae37286755cd212ed2c6b13ad34183970b2165
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
-F src/tclsqlite.c 4e64ba300a5a26e0f1170e09032429faeb65e45e8f3d1a7833e8edb69fc2979e
+F src/tclsqlite.c c5b9f6540d6de1adc6554589ce4011e07bb02250440a3e777ff86b40f1c1dd2c
 F src/test1.c 1356984e97bff07e4a8cc3863e892f05b3348678a74783bb6f350b76316736f1
 F src/test2.c 3efb99ab7f1fc8d154933e02ae1378bac9637da5
 F src/test3.c 61798bb0d38b915067a8c8e03f5a534b431181f802659a6616f9b4ff7d872644
@@ -595,7 +596,7 @@ F src/test_backup.c bf5da90c9926df0a4b941f2d92825a01bbe090a0
 F src/test_bestindex.c 8294d8223b7f18a3ddb7f9a0e30815dcca4e61681f78b538c870f7d934f88b81
 F src/test_blob.c ae4a0620b478548afb67963095a7417cd06a4ec0a56adb453542203bfdcb31ce
 F src/test_btree.c 8b2dc8b8848cf3a4db93f11578f075e82252a274
-F src/test_config.c 8264637b06a3c1f0727c88d1ea32dcf7986b9e7e358a970cae87cdac8a5b2708
+F src/test_config.c 73ebdc35580900d12c20b984db9ec1abe860dc75f66ae703f2b6fc9d95e09dc1
 F src/test_delete.c e2fe07646dff6300b48d49b2fee2fe192ed389e834dd635e3b3bac0ce0bf9f8f
 F src/test_demovfs.c 86142ba864d4297d54c5b2e972e74f3141ae4b30f05b3a95824184ed2d3d7f91
 F src/test_devsym.c aff2255ea290d7718da08af30cdf18e470ff7325a5eff63e0057b1496ed66593
@@ -619,11 +620,12 @@ F src/test_quota.c 6cb9297115b551f433a9ad1741817a9831abed99
 F src/test_quota.h 2a8ad1952d1d2ca9af0ce0465e56e6c023b5e15d
 F src/test_rtree.c 671f3fae50ff116ef2e32a3bf1fe21b5615b4b7b
 F src/test_schema.c f5d6067dfc2f2845c4dd56df63e66ee826fb23877855c785f75cc2ca83fd0c1b
+F src/test_schemapool.c ae21a79f9bc7e9099ae78dbd46d5c28ee75330e62e3256a9fde25564ff9df492
 F src/test_server.c a2615049954cbb9cfb4a62e18e2f0616e4dc38fe
 F src/test_sqllog.c 540feaea7280cd5f926168aee9deb1065ae136d0bbbe7361e2ef3541783e187a
 F src/test_superlock.c 4839644b9201da822f181c5bc406c0b2385f672e
 F src/test_syscall.c 1073306ba2e9bfc886771871a13d3de281ed3939
-F src/test_tclsh.c c4065ced25126e25c40122c5ff62dc89902ea617d72cdd27765151cdd7fcc477
+F src/test_tclsh.c ec192bceacfe67d427e97d4985a298b0aaadb266dfbc77c54425537c5e263b65
 F src/test_tclvar.c 33ff42149494a39c5fbb0df3d25d6fafb2f668888e41c0688d07273dcb268dfc
 F src/test_thread.c 269ea9e1fa5828dba550eb26f619aa18aedbc29fd92f8a5f6b93521fbb74a61c
 F src/test_vdbecov.c f60c6f135ec42c0de013a1d5136777aa328a776d33277f92abac648930453d43
@@ -634,32 +636,32 @@ F src/test_windirent.h 90dfbe95442c9762357fe128dc7ae3dc199d006de93eb33ba3972e0a9
 F src/test_window.c cdae419fdcea5bad6dcd9368c685abdad6deb59e9fc8b84b153de513d394ba3f
 F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
-F src/tokenize.c a38f52058b517929e264094abd0b5fd1e8e145a1aa43bc6f6a72ae5218f96c98
-F src/treeview.c 0bd550f5974565eba541db339906be7a3f9e91beafb879cb40705382887f08e1
-F src/trigger.c 61bea163b1fa3039bc572ed8312461b978e5c527e5301f302b078f4c1ccdec6a
+F src/tokenize.c 36eb0799e487759bbe73e5742b82ee676f06cea2515ff578d03c59a74ccf2d6c
+F src/treeview.c 07787f67cd297a6d09d04b8d70c06769c60c9c1d9080378f93929c16f8fd3298
+F src/trigger.c 53fbf255f234d23aa7b877a18e0024436eec88373b7c0ebe1ba3f69341dfa72c
 F src/update.c c52a7991bece0453d22c77c08469512ee2f1391c12503fd347d1c939220c5877
 F src/upsert.c 8789047a8f0a601ea42fa0256d1ba3190c13746b6ba940fe2d25643a7e991937
 F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
-F src/util.c 602fe229f32a96ceccae4f40824129669582096f7c355f53dbac156c9fecef23
-F src/vacuum.c bb346170b0b54c6683bba4a5983aea40485597fdf605c87ec8bc2e199fe88cd8
-F src/vdbe.c 3df15f0f2cd9d8faeeea18398a62f16c07fda2bfd8d726186f07508ad69b40e2
-F src/vdbe.h 07641758ca8b4f4c6d81ea667ea167c541e6ece21f5574da11e3d21ec37e2662
+F src/util.c 0be191521ff6d2805995f4910f0b6231b42843678b2efdc1abecaf39929a673f
+F src/vacuum.c 50f980eee45f25faf1faedc5be27a561c0df086e27bef12618485f10b3bae40b
+F src/vdbe.c e8793796792a70d9aab3560f8fb1c25f51d60d64bcb7c3f03be35823d81d156a
+F src/vdbe.h f521a8218438c6c41e84276ac668c1c3a5bf530e37d20d1021e8c8af533ea69e
 F src/vdbeInt.h 2cad0aeeb106371ed0e0946bab89f60627087068847afc2451c05056961c18da
 F src/vdbeapi.c 602610f1252d59cd69742f78a1e2f6fbae40a4b407f5506a6a7b869b0df08ff2
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-F src/vdbeblob.c 5e61ce31aca17db8fb60395407457a8c1c7fb471dde405e0cd675974611dcfcd
+F src/vdbeaux.c 910f617aab8a24e1591fc2d2a41e31d94866ce51c2ee04c62620e0f91926a5e9
+F src/vdbeblob.c aa23a326ff86bdde8f7ba74cf23c3e1795b13bee749314feaf26273be2f63e89
 F src/vdbemem.c 5ebf05c0182addedb1607ade848e1c83cef40981df94d1abfab0c59288c6064f
 F src/vdbesort.c 43756031ca7430f7aec3ef904824a7883c4ede783e51f280d99b9b65c0796e35
 F src/vdbetrace.c fe0bc29ebd4e02c8bc5c1945f1d2e6be5927ec12c06d89b03ef2a4def34bf823
 F src/vdbevtab.c f99b275366c5fc5e2d99f734729880994ab9500bdafde7fae3b02d562b9d323c
-F src/vtab.c 3d72c780d1ea08906a198e4f033921a658a54590e3ed72c544995d84f3f9464a
+F src/vtab.c 7064064da041cf67212c60229cb81d4f78337b4bece2aa2ecc3d50fb09b8fefc
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c b9df133a705093da8977da5eb202eaadb844839f1c7297c08d33471f5491843d
 F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
 F src/walker.c f890a3298418d7cba3b69b8803594fdc484ea241206a8dfa99db6dd36f8cbb3b
-F src/where.c 9a44063e60d8f42dd9dc8147b8e8dcfc315bbd13e25c395211292c36d828c869
+F src/where.c e7b7c9d37f4f8d14d4d05b20e57ae43712a51ffed7d45f547a23f9c42ee483dd
 F src/whereInt.h b48ca529ffe293c18cbfa8326af18a09e39910de66fb3e96ef788c7cbf8ef3a7
-F src/wherecode.c 0b09abfcb88c61c6a6984a3e065786631ff35495e9bdf865e6b74ab0a1299c5b
+F src/wherecode.c f8acceb057286ed95b66689d1981985228fd925001fdc49dbd3b112f4d739174
 F src/whereexpr.c 55a39f42aaf982574fbf52906371a84cceed98a994422198dfd03db4fce4cc46
 F src/window.c fff1b51757438c664e471d5184634e48dcdf8ea34b640f3b1b0810b1e06de18c
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
@@ -1007,7 +1009,7 @@ F test/fts3conf.test c84bbaec81281c1788aa545ac6e78a6bd6cde2bdbbce2da261690e3659f
 F test/fts3corrupt.test 6732477c5ace050c5758a40a8b5706c8c0cccd416b9c558e0e15224805a40e57
 F test/fts3corrupt2.test e318f0676e5e78d5a4b702637e2bb25265954c08a1b1e4aaf93c7880bb0c67d0
 F test/fts3corrupt3.test 0d5b69a0998b4adf868cc301fc78f3d0707745f1d984ce044c205cdb764b491f
-F test/fts3corrupt4.test 799ff994b964fed7201be6b6b62c7ff2ef7bb3da6c02b9eaf0d96a5a4d9b6ca3
+F test/fts3corrupt4.test 589e043d1114ea02c83530e459ef5c2d6adce63094e72826ed3bceb02e795116
 F test/fts3corrupt5.test 0549f85ec4bd22e992f645f13c59b99d652f2f5e643dac75568bfd23a6db7ed5
 F test/fts3corrupt6.test f417c910254f32c0bc9ead7affa991a1d5aec35b3b32a183ffb05eea78289525
 F test/fts3cov.test 7eacdbefd756cfa4dc2241974e3db2834e9b372ca215880e00032222f32194cf
@@ -1024,8 +1026,8 @@ F test/fts3expr3.test c4d4a7d6327418428c96e0a3a1137c251b8dfbf8
 F test/fts3expr4.test f5b2832549f01b1f7f73389fa21d4b875499bc95bf7c8b36271844888c6a0938
 F test/fts3expr5.test a5b9a053becbdb8e973fbf4d6d3abaabeb42d511d1848bd57931f3e0a1cf983e
 F test/fts3f.test 8c438d5e1cab526b0021988fb1dc70cf3597b006a33ffd6c955ee89929077fe3
-F test/fts3fault.test 798e45af84be7978ca33d5bdc94246eb44724db24174b5d8e9b1ac46c57fb08d
-F test/fts3fault2.test 6a17a11d8034b1c4eca9f3091649273d56c49ff049e2173df8060f94341e9da0
+F test/fts3fault.test f4e1342acfe6d216a001490e8cd52afac1f9ffe4a11bbcdcb296129a45c5df45
+F test/fts3fault2.test 7b2741e5095367238380b0fcdb837f36c24484c7a5f353659b387df63cf039ec
 F test/fts3first.test dbdedd20914c8d539aa3206c9b34a23775644641
 F test/fts3fuzz001.test e3c7b0ce9b04cc02281dcc96812a277f02df03cd7dc082055d87e11eb18aaf56
 F test/fts3join.test ee25def5e763ea8879c19e74f862d5191410ccc7259338887a3685e97f512662
@@ -1168,7 +1170,7 @@ F test/join4.test 1a352e4e267114444c29266ce79e941af5885916
 F test/join5.test d22b6cba8fb59ab3f1c82701434c360705eb12d4ce200c449f37b018fc47681a
 F test/join6.test f809c025fa253f9e150c0e9afd4cef8813257bceeb6f46e04041228c9403cc2c
 F test/join7.test 2268dcbb54b724391dda3748ea95c60d960607ffeed67885675998e7117697f6
-F test/join8.test d0e75bf880a1b1ee8fda57d8187170c5b2ff0c0cd0e1d6d474faa99fe1283d8d
+F test/join8.test ef5fb09a7ce6b59addb8bd16e11607db6c44a0afcac5774a5dc03193fd0a1df5
 F test/join9.test 9056ddd3b0c0f4f9d658f4521038d9a37dc23ead8ca9a505d0b0db2b6a471e05
 F test/joinA.test 7eab225dc1c1ab258a5e62513a4ed7cabbd3db971d59d5d92f4fb6fa14c12f6a
 F test/joinB.test 1b2ba3fc8568b49411787fccbf540570c148e9b6a53a30f80691cb6268098ded
@@ -1183,7 +1185,7 @@ F test/journal3.test 7c3cf23ffc77db06601c1fcfc9743de8441cb77db9d1aa931863d94f5ff
 F test/jrnlmode.test 9b5bc01dac22223cb60ec2d5f97acf568d73820794386de5634dcadbea9e1946
 F test/jrnlmode2.test 8759a1d4657c064637f8b079592651530db738419e1d649c6df7048cd724363d
 F test/jrnlmode3.test 556b447a05be0e0963f4311e95ab1632b11c9eaa
-F test/json101.test 9d46b8e254c4e23306da175dd226d5c4f164db6b294bcea98e5dcd891ba48c91
+F test/json101.test 9f6337e7423d2c1774d1d485c919fc4e11c8f7e423a2f8831f73471983432108
 F test/json102.test 327e77275f338c028faefa2da5164daf6b142a165e3015ff2a6e4251ddc6a0ac
 F test/json103.test 53df87f83a4e5fa0c0a56eb29ff6c94055c6eb919f33316d62161a8880112dbe
 F test/json104.test a502dc01853aada95d721b3b275afbe2dc18fffdac1fea6e96fb20c13586bbb5
@@ -1233,7 +1235,7 @@ F test/mallocJ.test b5d1839da331d96223e5f458856f8ffe1366f62e
 F test/mallocK.test 25897506da0098cea09b302ff432b0fb6d8002773c1e0fc9732aa8b444bfd455
 F test/mallocL.test fb311ff80afddf3b1a75e52289081f4754d901dc
 F test/mallocM.test 78bbe9d3da84a5c679123cdb40d7b2010b18fc46e13897e4f253c6ba6fbff134
-F test/malloc_common.tcl aac62499b76be719fac31e7a3e54a7fd53272e7f
+F test/malloc_common.tcl 806c50379cf4fa65008cd4d5af18273e5dac8ab62d1d4316c76aa2ecd2e54018
 F test/malloctraceviewer.tcl b7a54595270c1d201abf1c3f3d461f27eaf24cdef623ad08a0fe5e411264c8a9
 F test/manydb.test 28385ae2087967aa05c38624cec7d96ec74feb3e
 F test/mem5.test c6460fba403c5703141348cd90de1c294188c68f
@@ -1244,7 +1246,7 @@ F test/memjournal2.test 89a4e0d1084170a281efa4d54c2677599f986f44227f98f7dfae2828
 F test/memleak.test 10b9c6c57e19fc68c32941495e9ba1c50123f6e2
 F test/memsubsys1.test 9e7555a22173b8f1c96c281ce289b338fcba2abe8b157f8798ca195bbf1d347e
 F test/memsubsys2.test 3e4a8d0c05fd3e5fa92017c64666730a520c7e08
-F test/merge1.test 0ade470d77b689c4a64dc7f736527fcd893140bcafa70af8f7b98523cfb83f16
+F test/merge1.test 2de6d6ef8d25402764b1aab49d8f9d7f89208c89a6674e437f76de4c812157b8
 F test/minmax.test fe638b55d77d2375531a8f549b338eafcd9adfbd2f72df37ed77d9b26ca0a71a
 F test/minmax2.test cf9311babb6f0518d04e42fd6a42c619531c4309a9dd790a2c4e9b3bc595e0de
 F test/minmax3.test cc1e8b010136db0d01a6f2a29ba5a9f321034354
@@ -1285,7 +1287,7 @@ F test/null.test b7ff206a1c60fe01aa2abd33ef9ea83c93727d993ca8a613de86e925c9f2bc6
 F test/nulls1.test 7a5e4346ee4285034100b4cd20e6784f16a9d6c927e44ecdf10034086bbee9c9
 F test/numcast.test 5d126f7f581432e86a90d1e35cac625164aec4a1
 F test/numindex1.test 20a5450d4b056e48cd5db30e659f13347a099823
-F test/offset1.test f06b83657bcf26f9ce805e67450e189e282143b2
+F test/offset1.test 72cca52482cbd5bc687cfa67aa2566c859081b5a353fd2f9da9bbd3914dea1ef
 F test/openv2.test 0d3040974bf402e19b7df4b783e447289d7ab394
 F test/optfuzz-db01.c 9f2fa80b8f84ebbf1f2e8b13421a4e0477fe300f6686fbd76cac1d2db66e0fdc
 F test/optfuzz-db01.txt 21f6bdeadc701cf11528276e2a55c70bfcb846ba42df327f979bd9e7b6ce7041
@@ -1342,7 +1344,7 @@ F test/randexpr1.test eda062a97e60f9c38ae8d806b03b0ddf23d796df
 F test/rbu.test 168573d353cd0fd10196b87b0caa322c144ef736
 F test/rdonly.test 64e2696c322e3538df0b1ed624e21f9a23ed9ff8
 F test/recover.test ccb8c2623902a92ebb76770edd075cb4f75a4760bb7afde38026572c6e79070d
-F test/regexp1.test 0c3ff80f66b0eff80e623eb5db7a3dad512095c573d78ac23009785f6d8f51ce
+F test/regexp1.test 4a44e014664a109bbb1c37d29d9b61ca5aa5a7f49cc564c95208a80f818e3377
 F test/regexp2.test 55ed41da802b0e284ac7e2fe944be3948f93ff25abbca0361a609acfed1368b5
 F test/reindex.test cd9d6021729910ece82267b4f5e1b5ac2911a7566c43b43c176a6a4732e2118d
 F test/releasetest_data.tcl 11ba48a21ed1c808147b0e77c6e93d204577f4327ffe6d7c3b34cd3c01eac3a2
@@ -1350,6 +1352,13 @@ F test/resetdb.test 8062cf10a09d8c048f8de7711e94571c38b38168db0e5877ba7561789e5e
 F test/resolver01.test f4022acafda7f4d40eca94dbf16bc5fc4ac30ceb
 F test/returning1.test c43b8370a351f77aec6d71f4a2cde59b849369ed1933261a2c2c69e23e34ff5e
 F test/returningfault.test ae4c4b5e8745813287a359d9ccdb9d5c883c2e68afb18fb0767937d5de5692a4
+F test/reuse1.test faa2ce5ff566d936b8a10d9e22ba2ee66a54ce89fdcf8aef561df6b15b0ff3d3
+F test/reuse2.test 5dd9c98579358f0d5a90d25e36dd6e678a03e23446b6c7f2630a8da22ae7ca94
+F test/reuse3.test 876d15c42d61b1f6ab718cd8169912514ad314d7fe1cd9788080aa62168ba0d1
+F test/reuse4.test adaad66253aea6cc748674328abe69b650c5c78b8676ed1162d3de09742519f9
+F test/reuse5.test bbe6cf7384ef90f134392edd93d626385ef0bf6f40eefc3d993535cd0861d83b
+F test/reuse6.test f4674f9967aee2a0b49c02832120b8b495291c0d87aae084c54e6c0cc18132fe
+F test/reusefault.test ef646a0fb51d50ddfb4b7cd872f88e7d36eaba64bde7797b3418c3774e1c8d14
 F test/rollback.test 06680159bc6746d0f26276e339e3ae2f951c64812468308838e0a3362d911eaa
 F test/rollback2.test 3f3a4e20401825017df7e7671e9f31b6de5fae5620c2b9b49917f52f8c160a8f
 F test/rollbackfault.test 0e646aeab8840c399cfbfa43daab46fd609cf04a
@@ -1357,7 +1366,7 @@ F test/round1.test 768018b04522ca420b1aba8a24bd76091d269f3bce3902af3ec6ebcee41ab
 F test/rowallock.test 3f88ec6819489d0b2341c7a7528ae17c053ab7cc
 F test/rowhash.test 0bc1d31415e4575d10cacf31e1a66b5cc0f8be81
 F test/rowid.test e29025be95baf6b32f0d5edef59a7633028325896a98f1caa8019559ca910350
-F test/rowvalue.test ff1ffa31cebe12feb6f989e09263f3b1e8c560db94b40fe006126a8435fd6832
+F test/rowvalue.test baf4fa3ec1a8c1c920c3faa5fd25959cb454bbd99ac8960397c34549d9fc4abe
 F test/rowvalue2.test 060d238b7e5639a7c5630cb5e63e311b44efef2b
 F test/rowvalue3.test 1347e25ca11c547c5a6ff0cc5626f95aa9740e9275bfaec096029f57cb2130ce
 F test/rowvalue4.test 441e7e366ac6d939a3a95a574031c56ec2a854077a91d66eee5ff1d86cb5be58
@@ -1390,7 +1399,7 @@ F test/securedel.test 2f70b2449186a1921bd01ec9da407fbfa98c3a7a5521854c300c194b2f
 F test/securedel2.test 2d54c28e46eb1fd6902089958b20b1b056c6f1c5
 F test/select1.test 692e84cfa29c405854c69e8a4027183d64c22952866a123fabbce741a379e889
 F test/select2.test 352480e0e9c66eda9c3044e412abdf5be0215b56
-F test/select3.test 399a0b23f8618bfe07ea24fb67f2952f620d6eba662bccabf6f4f71c2d89e6c9
+F test/select3.test ce4f78bbc809b0513f960f1ee84cdbc5af50ba112c343d5266558a8b2468f656
 F test/select4.test f0684d3da3bccacbe2a1ebadf6fb49d9df6f53acb4c6ebc228a88d0d6054cc7b
 F test/select5.test 8afc5e5dcdebc2be54472e73ebd9cd1adef1225fd15d37a1c62f969159f390ae
 F test/select6.test 9b2fb4ffedf52e1b5703cfcae1212e7a4a063f014c0458d78d29aca3db766d1f
@@ -1497,7 +1506,7 @@ F test/tabfunc01.test 241425ce3998687ab24adba09cb95e8012e17499b84a0ed47e128ab45e
 F test/table.test eb3463b7add9f16a5bb836badf118cf391b809d09fdccd1f79684600d07ec132
 F test/tableapi.test ecbcc29c4ab62c1912c3717c48ea5c5e59f7d64e4a91034e6148bd2b82f177f4
 F test/tableopts.test dba698ba97251017b7c80d738c198d39ab747930
-F test/tclsqlite.test ad0bbd92edabe64cc91d990a0748142fe5ab962d74ac71fa3bfa94d50d2f4c87
+F test/tclsqlite.test 350536a4233914aa437b6735e3e8e683e921a71ced8fa9fb5396057a04dbea33
 F test/tempdb.test 4cdaa23ddd8acb4d79cbb1b68ccdfd09b0537aaba909ca69a876157c2a2cbd08
 F test/tempdb2.test 353864e96fd3ae2f70773d0ffbf8b1fe48589b02c2ec05013b540879410c3440
 F test/tempfault.test 0c0d349c9a99bf5f374655742577f8712c647900
@@ -1516,7 +1525,7 @@ F test/thread2.test f35d2106452b77523b3a2b7d1dcde2e5ee8f9e46
 F test/thread_common.tcl 334639cadcb9f912bf82aa73f49efd5282e6cadd
 F test/threadtest1.c 6029d9c5567db28e6dc908a0c63099c3ba6c383b
 F test/threadtest2.c a70a8e94bef23339d34226eb9521015ef99f4df8
-F test/threadtest3.c 655bff6c0895ec03f014126aa65e808fac9aae8c5a7a7da58a510cbe8b43b781
+F test/threadtest3.c 25cb92accb4fa6d53e708d6006ed2db7a7533ef7b838ef1306455c6fe57e978a
 F test/threadtest4.c c1e67136ceb6c7ec8184e56ac61db28f96bd2925
 F test/threadtest5.c 9b4d782c58d8915d7e955ff8051f3d03628bda0d33b82971ea8c0f2f2808c421
 F test/time-wordcount.sh 8e0b0f8109367827ad5d58f5cc849705731e4b90
@@ -1690,12 +1699,13 @@ F test/triggerF.test 5d76f0a8c428ff87a4d5ed52da06f6096a2c787a1e21b846111dfac4123
 F test/triggerG.test 2b816093c91ba73c733cfa8aedcc210ad819d72a98b1da30768a3c56505233e9
 F test/triggerupfrom.test d1f9e56090408115c522bee626cc33a2f3370f627a5e341d832589d72e3aa271
 F test/trustschema1.test 4e970aef0bfe0cee139703cc7209d0e0f07725d999b180ba50770f49edef1494
-F test/tt3_checkpoint.c ac7ca661d739280c89d9c253897df64a59a49369bd1247207ac0f655b622579d
-F test/tt3_index.c 39eec10a35f57672225be4d182862152896dee4a
-F test/tt3_lookaside1.c 0377e202c3c2a50d688cb65ba203afeda6fafeb9
+F test/tt3_checkpoint.c 69214e2ce81bbbd3c1b82c31e103607fd2e6790818aef4792957fc9cc88d067e
+F test/tt3_index.c 95592839426dc85ce5a7a57b41be2cbf3c2ec3457b9cd841a06ed5877f712c7c
+F test/tt3_lookaside1.c 2ddd99bfffeef288f0786827ef68f912f6f47ce3d3184e62f05808d8e13b920e
+F test/tt3_reuseschema.c 4d52e141f89f009028d8ab0bd1f0697d0edffa94bafc1fff0f7ad4d9d9baa549
 F test/tt3_shared.c b37d22defc944a2ac4c91c927fd06c1d48cd51e2ce9d004fe868625bd2399f93
-F test/tt3_stress.c f9a769ca8b026ecc76ee93ca8c9700a5619f8e51c581107c4053ba6ac97f616f
-F test/tt3_vacuum.c 71b254cde1fc49d6c8c44efd54f4668f3e57d7b3a8f4601ade069f75a999ba39
+F test/tt3_stress.c 077e817ac1168443b075fedb44e92db84bb4dc5bd3b6fe1aba25c94ac280b231
+F test/tt3_vacuum.c 727bfda1299b18435eeba80dee8e6ff43462146d7c1e2096cc809f01db568391
 F test/types.test bf816ce73c7dfcfe26b700c19f97ef4050d194ff
 F test/types2.test 1aeb81976841a91eef292723649b5c4fe3bc3cac
 F test/types3.test 99e009491a54f4dc02c06bdbc0c5eea56ae3e25a
@@ -1911,7 +1921,7 @@ F tool/mkmsvcmin.tcl 6ecab9fe22c2c8de4d82d4c46797bda3d2deac8e763885f5a38d0c44a89
 F tool/mkopcodec.tcl 33d20791e191df43209b77d37f0ff0904620b28465cca6990cf8d60da61a07ef
 F tool/mkopcodeh.tcl 5dab48c49a25452257494e9601702ab63adaba6bd54a9b382615fa52661c8f8c
 F tool/mkopts.tcl 680f785fdb09729fd9ac50632413da4eadbdf9071535e3f26d03795828ab07fa
-F tool/mkpragmatab.tcl bd07bd59d45d0f3448e123d6937e9811195f9908a51e09d774609883055bfd3d
+F tool/mkpragmatab.tcl 0e059aaab521b490c86ba3d4f945319b438558de7738e90f26c54f4ffcdd79bb
 F tool/mkshellc.tcl df5d249617f9cc94d5c48eb0401673eb3f31f383ecbc54e8a13ca3dd97e89450
 F tool/mksourceid.c 36aa8020014aed0836fd13c51d6dc9219b0df1761d6b5f58ff5b616211b079b9
 F tool/mkspeedsql.tcl a1a334d288f7adfe6e996f2e712becf076745c97
@@ -1978,11 +1988,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P cd6254fcd32798f7be4e6d827597ddaa2e46ac6e2f0149cd3a3be0416fa18835
-R 4b3e64a86ee9acaa4f97f1ab6ad6f3ae
-T +sym-major-release *
-T +sym-release *
-T +sym-version-3.39.0 *
+P efd54164b02f35b5d39ab4d18e349c18f3ec8afb728da39d20373e26742da177 a29f9949895322123f7c38fbe94c649a9d6e6c9cd0c3b41c96d694552f26b309
+R d0339000980575865473b9832db36209
 U drh
-Z f64bfe891f96e530fe80668f0f22f84a
+Z 31dd8436fe348e8e93bab7ea8a531a47
 # Remove this line to create a well-formed Fossil manifest.
@@ -1 +1 @@
-14e166f40dbfa6e055543f8301525f2ca2e96a02a57269818b9e69e162e98918
+8102592836dcf6f08749a516e126f3990a20f40866ed4a6e85d134ab49907ece
@@ -112,8 +112,8 @@ static void renameReloadSchema(Parse *pParse, int iDb, u16 p5){
  Vdbe *v = pParse->pVdbe;
  if( v ){
    sqlite3ChangeCookie(pParse, iDb);
-    sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iDb, 0, p5);
-    if( iDb!=1 ) sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, 1, 0, p5);
+    sqlite3VdbeAddParseSchemaOp(pParse, iDb, 0, p5);
+    if( iDb!=1 ) sqlite3VdbeAddParseSchemaOp(pParse, 1, 0, p5);
  }
 }

@@ -212,6 +212,7 @@ static void openStatTable(
        ** side-effect of the CREATE TABLE statement is to leave the rootpage 
        ** of the new table in register pParse->regRoot. This is important 
        ** because the OpenWrite opcode below will be needing it. */
+        sqlite3SchemaWritable(pParse, iDb);
        sqlite3NestedParse(pParse,
            "CREATE TABLE %Q.%s(%s)", pDb->zDbSName, zTab, aTable[i].zCols
        );
@@ -205,14 +205,14 @@ static void attachFunc(
  ** way we found it.
  */
  if( rc==SQLITE_OK ){
-    sqlite3BtreeEnterAll(db);
    db->init.iDb = 0;
    db->mDbFlags &= ~(DBFLAG_SchemaKnownOk);
-    if( !REOPEN_AS_MEMDB(db) ){
+    if( !IsSharedSchema(db) && !REOPEN_AS_MEMDB(db) ){
+      sqlite3BtreeEnterAll(db);
      rc = sqlite3Init(db, &zErrDyn);
+      sqlite3BtreeLeaveAll(db);
+      assert( zErrDyn==0 || rc!=SQLITE_OK );
    }
-    sqlite3BtreeLeaveAll(db);
-    assert( zErrDyn==0 || rc!=SQLITE_OK );
  }
 #ifdef SQLITE_USER_AUTHENTICATION
  if( rc==SQLITE_OK && !REOPEN_AS_MEMDB(db) ){
@@ -312,6 +312,7 @@ static void detachFunc(
    pEntry = sqliteHashNext(pEntry);
  }

+  (void)sqlite3SchemaDisconnect(db, i, 0);
  sqlite3BtreeClose(pDb->pBt);
  pDb->pBt = 0;
  pDb->pSchema = 0;
@@ -1548,7 +1548,7 @@ static int defragmentPage(MemPage *pPage, int nMaxFrag){
          if( iFree2+sz2 > usableSize ) return SQLITE_CORRUPT_PAGE(pPage);
          memmove(&data[iFree+sz+sz2], &data[iFree+sz], iFree2-(iFree+sz));
          sz += sz2;
-        }else if( NEVER(iFree+sz>usableSize) ){
+        }else if( iFree+sz>usableSize ){
          return SQLITE_CORRUPT_PAGE(pPage);
        }

@@ -7904,8 +7904,6 @@ static int balance_nonroot(
  Pgno pgno;                   /* Temp var to store a page number in */
  u8 abDone[NB+2];             /* True after i'th new page is populated */
  Pgno aPgno[NB+2];            /* Page numbers of new pages before shuffling */
-  Pgno aPgOrder[NB+2];         /* Copy of aPgno[] used for sorting pages */
-  u16 aPgFlags[NB+2];          /* flags field of new pages before shuffling */
  CellArray b;                 /* Parsed information on cells being balanced */

  memset(abDone, 0, sizeof(abDone));
@@ -8329,42 +8327,39 @@ static int balance_nonroot(
  ** of the table is closer to a linear scan through the file. That in turn 
  ** helps the operating system to deliver pages from the disk more rapidly.
  **
-  ** An O(n^2) insertion sort algorithm is used, but since n is never more 
-  ** than (NB+2) (a small constant), that should not be a problem.
+  ** An O(N*N) sort algorithm is used, but since N is never more than NB+2
+  ** (5), that is not a performance concern.
  **
  ** When NB==3, this one optimization makes the database about 25% faster 
  ** for large insertions and deletions.
  */
  for(i=0; i<nNew; i++){
-    aPgOrder[i] = aPgno[i] = apNew[i]->pgno;
-    aPgFlags[i] = apNew[i]->pDbPage->flags;
-    for(j=0; j<i; j++){
-      if( NEVER(aPgno[j]==aPgno[i]) ){
-        /* This branch is taken if the set of sibling pages somehow contains
-        ** duplicate entries. This can happen if the database is corrupt. 
-        ** It would be simpler to detect this as part of the loop below, but
-        ** we do the detection here in order to avoid populating the pager
-        ** cache with two separate objects associated with the same
-        ** page number.  */
-        assert( CORRUPT_DB );
-        rc = SQLITE_CORRUPT_BKPT;
-        goto balance_cleanup;
-      }
-    }
+    aPgno[i] = apNew[i]->pgno;
+    assert( apNew[i]->pDbPage->flags & PGHDR_WRITEABLE );
+    assert( apNew[i]->pDbPage->flags & PGHDR_DIRTY );
  }
-  for(i=0; i<nNew; i++){
-    int iBest = 0;                /* aPgno[] index of page number to use */
-    for(j=1; j<nNew; j++){
-      if( aPgOrder[j]<aPgOrder[iBest] ) iBest = j;
+  for(i=0; i<nNew-1; i++){
+    int iB = i;
+    for(j=i+1; j<nNew; j++){
+      if( apNew[j]->pgno < apNew[iB]->pgno ) iB = j;
    }
-    pgno = aPgOrder[iBest];
-    aPgOrder[iBest] = 0xffffffff;
-    if( iBest!=i ){
-      if( iBest>i ){
-        sqlite3PagerRekey(apNew[iBest]->pDbPage, pBt->nPage+iBest+1, 0);
-      }
-      sqlite3PagerRekey(apNew[i]->pDbPage, pgno, aPgFlags[iBest]);
-      apNew[i]->pgno = pgno;
+
+    /* If apNew[i] has a page number that is bigger than any of the
+    ** subsequence apNew[i] entries, then swap apNew[i] with the subsequent
+    ** entry that has the smallest page number (which we know to be
+    ** entry apNew[iB]).
+    */
+    if( iB!=i ){
+      Pgno pgnoA = apNew[i]->pgno;
+      Pgno pgnoB = apNew[iB]->pgno;
+      Pgno pgnoTemp = (PENDING_BYTE/pBt->pageSize)+1;
+      u16 fgA = apNew[i]->pDbPage->flags;
+      u16 fgB = apNew[iB]->pDbPage->flags;
+      sqlite3PagerRekey(apNew[i]->pDbPage, pgnoTemp, fgB);
+      sqlite3PagerRekey(apNew[iB]->pDbPage, pgnoA, fgA);
+      sqlite3PagerRekey(apNew[i]->pDbPage, pgnoB, fgB);
+      apNew[i]->pgno = pgnoB;
+      apNew[iB]->pgno = pgnoA;
    }
  }

@@ -331,8 +331,6 @@ void sqlite3NestedParse(Parse *pParse, const char *zFormat, ...){
  memset(PARSE_TAIL(pParse), 0, PARSE_TAIL_SZ);
  db->mDbFlags |= DBFLAG_PreferBuiltin;
  sqlite3RunParser(pParse, zSql);
-  sqlite3DbFree(db, pParse->zErrMsg);
-  pParse->zErrMsg = 0;
  db->mDbFlags = savedDbFlags;
  sqlite3DbFree(db, zSql);
  memcpy(PARSE_TAIL(pParse), saveBuf, PARSE_TAIL_SZ);
@@ -349,6 +347,39 @@ int sqlite3UserAuthTable(const char *zTable){
 }
 #endif

+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+/*
+** If this database connection was opened with the SQLITE_OPEN_SHARED_SCHEMA
+** flag specified, then ensure that the database schema for database iDb
+** is loaded. Either by obtaining a Schema object from the schema-pool, or
+** by reading the contents of the sqlite_master table. Unless it is NULL, 
+** the location indicated by parameter pbUnload is set to 1 if a shared-schema 
+** is loaded.
+**
+** If the database handle was not opened with SQLITE_OPEN_SHARED_SCHEMA, or
+** if the schema for database iDb is already loaded, this function is a no-op.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise. If
+** an error code is returned, (*pzErr) may be set to point to a buffer
+** containing an error message. It is the responsibility of the caller to
+** eventually free this buffer using sqlite3_free().
+*/
+int sqlite3SchemaLoad(sqlite3 *db, int iDb, int *pbUnload, char **pzErr){
+  int rc = SQLITE_OK;
+  if( IsSharedSchema(db) 
+      && DbHasProperty(db, iDb, DB_SchemaLoaded)==0 
+      && (db->init.busy==0 || (iDb!=1 && db->init.iDb==1))
+  ){
+    struct sqlite3InitInfo sv = db->init;
+    memset(&db->init, 0, sizeof(struct sqlite3InitInfo));
+    rc = sqlite3InitOne(db, iDb, pzErr, 0);
+    db->init = sv;
+    if( pbUnload && rc==SQLITE_OK && iDb!=1 ) *pbUnload = 1;
+  }
+  return rc;
+}
+#endif
+
 /*
 ** Locate the in-memory structure that describes a particular database
 ** table given the name of that table and (optionally) the name of the
@@ -374,59 +405,41 @@ Table *sqlite3FindTable(sqlite3 *db, const char *zName, const char *zDatabase){
    return 0;
  }
 #endif
-  if( zDatabase ){
-    for(i=0; i<db->nDb; i++){
-      if( sqlite3StrICmp(zDatabase, db->aDb[i].zDbSName)==0 ) break;
-    }
-    if( i>=db->nDb ){
-      /* No match against the official names.  But always match "main"
-      ** to schema 0 as a legacy fallback. */
-      if( sqlite3StrICmp(zDatabase,"main")==0 ){
-        i = 0;
-      }else{
-        return 0;
-      }
-    }
-    p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash, zName);
-    if( p==0 && sqlite3StrNICmp(zName, "sqlite_", 7)==0 ){
-      if( i==1 ){
-        if( sqlite3StrICmp(zName+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0
-         || sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0
-         || sqlite3StrICmp(zName+7, &LEGACY_SCHEMA_TABLE[7])==0
-        ){
-          p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash, 
-                              LEGACY_TEMP_SCHEMA_TABLE);
+  while(1){
+    for(i=OMIT_TEMPDB; i<db->nDb; i++){
+      int j = (i<2) ? i^1 : i;   /* Search TEMP before MAIN */
+      if( zDatabase==0 || sqlite3DbIsNamed(db, j, zDatabase) ){
+        int bUnload = 0;
+        assert( sqlite3SchemaMutexHeld(db, j, 0) );
+        if( IsSharedSchema(db) ){
+          Parse *pParse = db->pParse;
+          if( pParse && pParse->nErr==0 ){
+            pParse->rc = sqlite3SchemaLoad(db, j, &bUnload, &pParse->zErrMsg);
+            if( pParse->rc ) pParse->nErr++;
+          }
        }
-      }else{
-        if( sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0 ){
-          p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash,
-                              LEGACY_SCHEMA_TABLE);
+        p = sqlite3HashFind(&db->aDb[j].pSchema->tblHash, zName);
+        if( p ) return p;
+        if( bUnload ){
+          sqlite3SchemaRelease(db, j);
        }
      }
    }
-  }else{
-    /* Match against TEMP first */
-    p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash, zName);
-    if( p ) return p;
-    /* The main database is second */
-    p = sqlite3HashFind(&db->aDb[0].pSchema->tblHash, zName);
-    if( p ) return p;
-    /* Attached databases are in order of attachment */
-    for(i=2; i<db->nDb; i++){
-      assert( sqlite3SchemaMutexHeld(db, i, 0) );
-      p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash, zName);
-      if( p ) break;
+    /* Not found.  If the name we were looking for was temp.sqlite_master
+    ** then change the name to sqlite_temp_master and try again. */
+    if( sqlite3StrICmp(zName, PREFERRED_SCHEMA_TABLE)==0 ){
+      zName = LEGACY_SCHEMA_TABLE;
+      continue;
    }
-    if( p==0 && sqlite3StrNICmp(zName, "sqlite_", 7)==0 ){
-      if( sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0 ){
-        p = sqlite3HashFind(&db->aDb[0].pSchema->tblHash, LEGACY_SCHEMA_TABLE);
-      }else if( sqlite3StrICmp(zName+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0 ){
-        p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash, 
-                            LEGACY_TEMP_SCHEMA_TABLE);
-      }
+    if( sqlite3StrICmp(zName, PREFERRED_TEMP_SCHEMA_TABLE)==0 ){
+      zName = LEGACY_TEMP_SCHEMA_TABLE;
+      continue;
    }
+    if( sqlite3StrICmp(zName, LEGACY_SCHEMA_TABLE)!=0 ) break;
+    if( sqlite3_stricmp(zDatabase, db->aDb[1].zDbSName)!=0 ) break;
+    zName = LEGACY_TEMP_SCHEMA_TABLE;
  }
-  return p;
+  return 0;
 }

 /*
@@ -451,6 +464,7 @@ Table *sqlite3LocateTable(
  /* Read the database schema. If an error occurs, leave an error message
  ** and code in pParse and return NULL. */
  if( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 
+   && !IsSharedSchema(db)
   && SQLITE_OK!=sqlite3ReadSchema(pParse)
  ){
    return 0;
@@ -467,9 +481,21 @@ Table *sqlite3LocateTable(
      if( pMod==0 && sqlite3_strnicmp(zName, "pragma_", 7)==0 ){
        pMod = sqlite3PragmaVtabRegister(db, zName);
      }
-      if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
-        testcase( pMod->pEpoTab==0 );
-        return pMod->pEpoTab;
+      if( pMod ){
+        if( IsSharedSchema(db) && pParse->nErr==0 ){
+          int bDummy = 0;
+          pParse->rc = sqlite3SchemaLoad(db, 0, &bDummy, &pParse->zErrMsg);
+          if( pParse->rc ) pParse->nErr++;
+          (void)bDummy;
+        }
+        if( sqlite3VtabEponymousTableInit(pParse, pMod) ){
+          Table *pEpoTab = pMod->pEpoTab;
+          if( pEpoTab ){
+            assert( IsSharedSchema(db)||pEpoTab->pSchema==db->aDb[0].pSchema );
+            pEpoTab->pSchema = db->aDb[0].pSchema;  /* For SHARED_SCHEMA mode */
+          }
+          return pEpoTab;
+        }
      }
    }
 #endif
@@ -479,15 +505,13 @@ Table *sqlite3LocateTable(
    p = 0;
  }

-  if( p==0 ){
+  if( p==0 && (!IsSharedSchema(db) || pParse->nErr==0) ){
    const char *zMsg = flags & LOCATE_VIEW ? "no such view" : "no such table";
    if( zDbase ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
    }
-  }else{
-    assert( HasRowid(p) || p->iPKey<0 );
  }

  return p;
@@ -656,11 +680,10 @@ void sqlite3ResetOneSchema(sqlite3 *db, int iDb){
    DbSetProperty(db, 1, DB_ResetWanted);
    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
  }
-
  if( db->nSchemaLock==0 ){
    for(i=0; i<db->nDb; i++){
      if( DbHasProperty(db, i, DB_ResetWanted) ){
-        sqlite3SchemaClear(db->aDb[i].pSchema);
+        sqlite3SchemaClearOrDisconnect(db, i);
      }
    }
  }
@@ -673,16 +696,17 @@ void sqlite3ResetOneSchema(sqlite3 *db, int iDb){
 void sqlite3ResetAllSchemasOfConnection(sqlite3 *db){
  int i;
  sqlite3BtreeEnterAll(db);
-  for(i=0; i<db->nDb; i++){
+  for(i=0; i<db->nDb; i=(i?i+1:2)){
    Db *pDb = &db->aDb[i];
    if( pDb->pSchema ){
      if( db->nSchemaLock==0 ){
-        sqlite3SchemaClear(pDb->pSchema);
+        sqlite3SchemaClearOrDisconnect(db, i);
      }else{
        DbSetProperty(db, i, DB_ResetWanted);
      }
    }
  }
+  sqlite3SchemaClear(db->aDb[1].pSchema);
  db->mDbFlags &= ~(DBFLAG_SchemaChange|DBFLAG_SchemaKnownOk);
  sqlite3VtabUnlockList(db);
  sqlite3BtreeLeaveAll(db);
@@ -1287,7 +1311,7 @@ void sqlite3StartTable(
  */
  if( !IN_SPECIAL_PARSE ){
    char *zDb = db->aDb[iDb].zDbSName;
-    if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    if( !IsSharedSchema(db) && SQLITE_OK!=sqlite3ReadSchema(pParse) ){
      goto begin_table_error;
    }
    pTable = sqlite3FindTable(db, zName, zDb);
@@ -2912,7 +2936,7 @@ void sqlite3EndTable(
 #endif

    /* Reparse everything to update our internal data structures */
-    sqlite3VdbeAddParseSchemaOp(v, iDb,
+    sqlite3VdbeAddParseSchemaOp(pParse, iDb,
           sqlite3MPrintf(db, "tbl_name='%q' AND type!='trigger'", p->zName),0);
  }

@@ -3465,7 +3489,7 @@ void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
  }
  assert( pParse->nErr==0 );
  assert( pName->nSrc==1 );
-  if( sqlite3ReadSchema(pParse) ) goto exit_drop_table;
+  if( !IsSharedSchema(db) && sqlite3ReadSchema(pParse) ) goto exit_drop_table;
  if( noErr ) db->suppressErr++;
  assert( isView==0 || isView==LOCATE_VIEW );
  pTab = sqlite3LocateTableItem(pParse, isView, &pName->a[0]);
@@ -3480,6 +3504,7 @@ void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb>=0 && iDb<db->nDb );
+  sqlite3SchemaWritable(pParse, iDb);

  /* If pTab is a virtual table, call ViewGetColumnNames() to ensure
  ** it is initialized.
@@ -3934,7 +3959,7 @@ void sqlite3CreateIndex(
  if( IN_DECLARE_VTAB && idxType!=SQLITE_IDXTYPE_PRIMARYKEY ){
    goto exit_create_index;
  }
-  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+  if( !IsSharedSchema(db) && SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    goto exit_create_index;
  }
  if( sqlite3HasExplicitNulls(pParse, pList) ){
@@ -4432,7 +4457,7 @@ void sqlite3CreateIndex(
      if( pTblName ){
        sqlite3RefillIndex(pParse, pIndex, iMem);
        sqlite3ChangeCookie(pParse, iDb);
-        sqlite3VdbeAddParseSchemaOp(v, iDb,
+        sqlite3VdbeAddParseSchemaOp(pParse, iDb,
            sqlite3MPrintf(db, "name='%q' AND type='index'", pIndex->zName), 0);
        sqlite3VdbeAddOp2(v, OP_Expire, 0, 1);
      }
@@ -4582,6 +4607,7 @@ void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
    goto exit_drop_index;
  }
  iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
+  sqlite3SchemaWritable(pParse, iDb);
 #ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_INDEX;
@@ -16,6 +16,63 @@

 #include "sqliteInt.h"

+/*
+** Connections opened with the SQLITE_OPEN_SHARED_SCHEMA flag specified
+** may use SchemaPool objects for any database that is not the temp db
+** (iDb==1). For such databases (type "struct Db") there are three states
+** the Schema/SchemaPool object may be in.
+**
+**   1) pSPool==0, pSchema points to an empty object allocated by
+**      sqlite3_malloc(). DB_SchemaLoaded flag is clear.
+**
+**   2) pSPool!=0, pSchema points to a populated object owned by the
+**      SchemaPool. DB_SchemaLoaded flag is set.
+**
+**   3) pSPool!=0, pSchema points to the SchemaPool's static object
+**      (SchemaPool.sSchema).
+*/
+struct SchemaPool {
+  int nRef;                       /* Number of pointers to this object */
+  int nDelete;                    /* Schema objects deleted by ReleaseAll() */
+  u64 cksum;                      /* Checksum for this Schema contents */
+  Schema *pSchema;                /* Linked list of Schema objects */
+  Schema sSchema;                 /* The single dummy schema object */
+  SchemaPool *pNext;              /* Next element in schemaPoolList */
+};
+
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+#ifdef SQLITE_DEBUG
+static void assert_schema_state_ok(sqlite3 *db){
+  if( IsSharedSchema(db) && db->eOpenState!=SQLITE_STATE_ZOMBIE ){
+    int i;
+    for(i=0; i<db->nDb; i++){
+      if( i!=1 ){
+        Db *pDb = &db->aDb[i];
+        Btree *pBt = pDb->pBt;
+        if( pBt==0 ) continue;
+        assert( sqlite3BtreeSchema(pBt, 0, 0)==0 );
+        assert( pDb->pSchema );
+        if( pDb->pSPool ){
+          if( DbHasProperty(db, i, DB_SchemaLoaded)==0 ){
+            assert( pDb->pSchema->tblHash.count==0 );
+            assert( pDb->pSchema==&pDb->pSPool->sSchema );
+          }else{
+            assert( pDb->pSchema!=&pDb->pSPool->sSchema );
+          }
+        }else{
+          assert( DbHasProperty(db, i, DB_SchemaLoaded)==0 );
+          assert( pDb->pSchema->tblHash.count==0 );
+          assert( pDb->pSchema!=&pDb->pSPool->sSchema );
+        }
+      }
+    }
+  }
+}
+#else
+# define assert_schema_state_ok(x)
+#endif
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+
 /*
 ** Invoke the 'collation needed' callback to request a collation sequence
 ** in the encoding enc of name zName, length nName.
@@ -514,15 +571,317 @@ void sqlite3SchemaClear(void *p){
 }

 /*
-** Find and return the schema associated with a BTree.  Create
-** a new one if necessary.
+** If this database was opened with the SQLITE_OPEN_SHARED_SCHEMA flag
+** and iDb!=1, then disconnect from the schema-pool associated with
+** database iDb. Otherwise, clear the Schema object belonging to
+** database iDb. 
+**
+** If an OOM error occurs while disconnecting from a schema-pool, 
+** the db->mallocFailed flag is set.
+*/
+void sqlite3SchemaClearOrDisconnect(sqlite3 *db, int iDb){
+  Db *pDb = &db->aDb[iDb];
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  if( IsSharedSchema(db) && iDb!=1 && pDb->pSPool ){
+    sqlite3SchemaDisconnect(db, iDb, 1);
+  }else
+#endif
+  {
+    sqlite3SchemaClear(pDb->pSchema);
+  }
+}
+
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+/*
+** Global linked list of SchemaPool objects. Read and write access must
+** be protected by the SQLITE_MUTEX_STATIC_MASTER mutex.
+*/
+static SchemaPool *SQLITE_WSD schemaPoolList = 0;
+
+#ifdef SQLITE_TEST
+/*
+** Return a pointer to the head of the linked list of SchemaPool objects.
+** This is used by the virtual table in file test_schemapool.c.
+*/
+SchemaPool *sqlite3SchemaPoolList(void){ return schemaPoolList; }
+#endif
+
+/*
+** Database handle db was opened with the SHARED_SCHEMA flag, and database
+** iDb is currently connected to a schema-pool. When this function is called,
+** (*pnByte) is set to nInit plus the amount of memory used to store a 
+** single instance of the Schema objects managed by the schema-pool.
+** This function adjusts (*pnByte) sot hat it is set to nInit plus
+** (nSchema/nRef) of the amount of memory used by a single Schema object,
+** where nSchema is the number of Schema objects allocated by this pool,
+** and nRef is the number of connections to the schema-pool.
+*/
+void sqlite3SchemaAdjustUsed(sqlite3 *db, int iDb, int nInit, int *pnByte){
+  SchemaPool *pSPool = db->aDb[iDb].pSPool;
+  int nSchema = 0;
+  Schema *p;
+  sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+  for(p=pSPool->pSchema; p; p=p->pNext){
+    nSchema++;
+  }
+  *pnByte = nInit + ((*pnByte - nInit) * nSchema) / pSPool->nRef;
+  sqlite3_mutex_leave( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+}
+
+/*
+** Check that the schema of db iDb is writable (either because it is the 
+** temp db schema or because the db handle was opened without
+** SQLITE_OPEN_SHARED_SCHEMA). If so, do nothing. Otherwise, leave an 
+** error in the Parse object.
+*/
+void sqlite3SchemaWritable(Parse *pParse, int iDb){
+  if( iDb!=1 && IsSharedSchema(pParse->db) && IN_DECLARE_VTAB==0 ){
+    sqlite3ErrorMsg(pParse, "attempt to modify read-only schema");
+  }
+}
+
+/*
+** The schema object passed as the only argument was allocated using
+** sqlite3_malloc() and then populated using the usual mechanism. This
+** function frees both the Schema object and its contents.
+*/
+static void schemaDelete(Schema *pSchema){
+  sqlite3SchemaClear((void*)pSchema);
+  sqlite3_free(pSchema);
+}
+
+/*
+** When this function is called, the database connection Db must be
+** using a schema-pool (Db.pSPool!=0) and must currently have Db.pSchema
+** set to point to a populated schema object checked out from the 
+** schema-pool. It is also assumed that the STATIC_MASTER mutex is held.
+** This function returns the Schema object to the schema-pool and sets
+** Db.pSchema to point to the schema-pool's static, empty, Schema object.
+*/
+static void schemaRelease(sqlite3 *db, Db *pDb){
+  Schema *pRelease = pDb->pSchema;
+  SchemaPool *pSPool = pDb->pSPool;
+
+  assert( pDb->pSchema->iGeneration==pSPool->sSchema.iGeneration );
+  pDb->pSchema = &pSPool->sSchema;
+
+  assert( pDb->pSPool && pRelease );
+  assert( pRelease->schemaFlags & DB_SchemaLoaded );
+  assert( (pDb->pSchema->schemaFlags & DB_SchemaLoaded)==0 );
+  assert( sqlite3_mutex_held(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER)) );
+
+  /* If the DBFLAG_FreeSchema flag is set and the database connection holds
+  ** at least one other copy of the schema being released, delete it instead
+  ** of returning it to the schema-pool.  */
+  if( db->mDbFlags & DBFLAG_FreeSchema ){
+    int i;
+    for(i=0; i<db->nDb; i++){
+      Db *p = &db->aDb[i];
+      if( p!=pDb && p->pSchema!=&pSPool->sSchema && pDb->pSPool==p->pSPool ){
+        pSPool->nDelete++;
+        schemaDelete(pRelease);
+        return;
+      }
+    }
+  }
+
+  pRelease->pNext = pDb->pSPool->pSchema;
+  pDb->pSPool->pSchema = pRelease;
+}
+
+/*
+** The schema for database iDb of database handle db, which was opened
+** with SQLITE_OPEN_SHARED_SCHEMA, has just been parsed. This function either
+** finds a matching SchemaPool object on the global list (schemaPoolList) or
+** else allocates a new one and sets the Db.pSPool variable accordingly.
+**
+** SQLITE_OK is returned if no error occurs, or an SQLite error code 
+** (SQLITE_NOMEM) otherwise.
+*/
+int sqlite3SchemaConnect(sqlite3 *db, int iDb, u64 cksum){
+  Schema *pSchema = db->aDb[iDb].pSchema;
+  SchemaPool *p;
+
+  assert( pSchema && iDb!=1 && db->aDb[iDb].pSPool==0 );
+
+  sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+
+  /* Search for a matching SchemaPool object */
+  for(p=schemaPoolList; p; p=p->pNext){
+    if( p->cksum==cksum && p->sSchema.schema_cookie==pSchema->schema_cookie ){
+      break;
+    }
+  }
+  if( !p ){
+    /* No SchemaPool object found. Allocate a new one. */
+    p = (SchemaPool*)sqlite3_malloc(sizeof(SchemaPool));
+    if( p ){
+      memset(p, 0, sizeof(SchemaPool));
+      p->cksum = cksum;
+      p->pNext = schemaPoolList;
+      schemaPoolList = p;
+
+      p->sSchema.schema_cookie = pSchema->schema_cookie;
+      p->sSchema.iGeneration = pSchema->iGeneration;
+      p->sSchema.file_format = pSchema->file_format;
+      p->sSchema.enc = pSchema->enc;
+      p->sSchema.cache_size = pSchema->cache_size;
+    }
+  }
+
+  if( p ) p->nRef++;
+
+  /* If the SchemaPool contains one or more free schemas at the moment, 
+  ** delete one of them. */
+  if( p && p->pSchema ){
+    Schema *pDel = p->pSchema;
+    p->pSchema = pDel->pNext;
+    schemaDelete(pDel);
+  }
+
+  sqlite3_mutex_leave( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+
+  db->aDb[iDb].pSPool = p;
+  return (p ? SQLITE_OK : SQLITE_NOMEM);
+}
+
+/*
+** If parameter iDb is 1 (the temp db), or if connection handle db was not
+** opened with the SQLITE_OPEN_SHARED_SCHEMA flag, this function is a no-op.
+** Otherwise, it disconnects from the schema-pool associated with database
+** iDb, assuming it is connected.
+**
+** If parameter bNew is true, then Db.pSchema is set to point to a new, empty,
+** Schema object obtained from sqlite3_malloc(). Or, if bNew is false, then
+** Db.pSchema is set to NULL before returning.
+**
+** If the bNew parameter is true, then this function may allocate memory. 
+** If the allocation attempt fails, then SQLITE_NOMEM is returned and the
+** schema-pool is not disconnected from. Or, if no OOM error occurs, 
+** SQLITE_OK is returned.
+*/
+int sqlite3SchemaDisconnect(sqlite3 *db, int iDb, int bNew){
+  int rc = SQLITE_OK;
+  if( IsSharedSchema(db) ){
+    Db *pDb = &db->aDb[iDb];
+    SchemaPool *pSPool = pDb->pSPool;
+    assert_schema_state_ok(db);
+    assert( pDb->pSchema );
+
+    if( pSPool==0 ){
+      assert( pDb->pVTable==0 );
+      assert( bNew==0 );
+      schemaDelete(pDb->pSchema);
+      pDb->pSchema = 0;
+    }else{
+      VTable *p;
+      VTable *pNext;
+      for(p=pDb->pVTable; p; p=pNext){
+        pNext = p->pNext;
+        sqlite3VtabUnlock(p);
+      }
+      pDb->pVTable = 0;
+      sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+      if( DbHasProperty(db, iDb, DB_SchemaLoaded) ){
+        schemaRelease(db, pDb);
+      }
+      if( bNew ){
+        Schema *pNew = sqlite3SchemaGet(db, 0);
+        if( pNew==0 ){
+          rc = SQLITE_NOMEM;
+        }else{
+          pDb->pSchema = pNew;
+        }
+      }
+      if( rc==SQLITE_OK ){
+        assert( pSPool->nRef>=1 );
+        pDb->pSPool = 0;
+        pSPool->nRef--;
+        if( pSPool->nRef<=0 ){
+          SchemaPool **pp;
+          while( pSPool->pSchema ){
+            Schema *pNext = pSPool->pSchema->pNext;
+            schemaDelete(pSPool->pSchema);
+            pSPool->pSchema = pNext;
+          }
+          for(pp=&schemaPoolList; (*pp)!=pSPool; pp=&((*pp)->pNext));
+          *pp = pSPool->pNext;
+          sqlite3_free(pSPool);
+        }
+      }
+      sqlite3_mutex_leave( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+    }
+  }
+  return rc;
+}
+
+/*
+** Extract and return a pointer to a schema object from the SchemaPool passed
+** as the only argument, if one is available. If one is not available, return
+** NULL.
+*/
+Schema *sqlite3SchemaExtract(SchemaPool *pSPool){
+  Schema *pRet = 0;
+  sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+  if( pSPool->pSchema ){
+    pRet = pSPool->pSchema;
+    pSPool->pSchema = pRet->pNext;
+    pRet->pNext = 0;
+  }
+  sqlite3_mutex_leave( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+  return pRet;
+}
+
+/*
+** Return all sharable schemas held by database handle db back to their
+** respective schema-pools. Db.pSchema variables are left pointing to
+** the static, empty, Schema object owned by each schema-pool.
+*/
+void sqlite3SchemaReleaseAll(sqlite3 *db){
+  int i;
+  assert_schema_state_ok(db);
+  sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+  for(i=0; i<db->nDb; i++){
+    if( i!=1 ){
+      Db *pDb = &db->aDb[i];
+      if( pDb->pSPool && DbHasProperty(db,i,DB_SchemaLoaded) ){
+        schemaRelease(db, pDb);
+      }
+    }
+  }
+  db->mDbFlags &= ~DBFLAG_FreeSchema;
+  sqlite3_mutex_leave( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+}
+
+/*
+** Release any sharable schema held by connection iDb of database handle
+** db. Db.pSchema is left pointing to the static, empty, Schema object
+** owned by the schema-pool.
+*/
+void sqlite3SchemaRelease(sqlite3 *db, int iDb){
+  Db *pDb = &db->aDb[iDb];
+  assert( iDb!=1 );
+  assert_schema_state_ok(db);
+  sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+  schemaRelease(db, pDb);
+  sqlite3_mutex_leave( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
+}
+
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+
+/*
+** In most cases, this function finds and returns the schema associated 
+** with BTree handle pBt, creating a new one if necessary. However, if
+** the database handle was opened with the SQLITE_OPEN_SHARED_SCHEMA flag
+** specified, a new, empty, Schema object in memory obtained by 
+** sqlite3_malloc() is always returned.
 */
 Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
-  Schema * p;
-  if( pBt ){
-    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
+  Schema *p;
+  if( pBt && IsSharedSchema(db)==0 ){
+    p = (Schema*)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
  }else{
-    p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
+    p = (Schema*)sqlite3DbMallocZero(0, sizeof(Schema));
  }
  if( !p ){
    sqlite3OomFault(db);
@@ -310,6 +310,9 @@ static const char * const sqlite3azCompileOpt[] = {
 #ifdef SQLITE_ENABLE_SESSION
  "ENABLE_SESSION",
 #endif
+#if SQLITE_ENABLE_SHARED_SCHEMA
+  "ENABLE_SHARED_SCHEMA",
+#endif
 #ifdef SQLITE_ENABLE_SNAPSHOT
  "ENABLE_SNAPSHOT",
 #endif
@@ -1164,6 +1164,17 @@ static void disconnectAllVtab(sqlite3 *db){
        if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
      }
    }
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+    if( IsSharedSchema(db) && i!=1 ){
+      VTable *pVTable;
+      VTable *pNext;
+      for(pVTable=db->aDb[i].pVTable; pVTable; pVTable=pNext){
+        pNext = pVTable->pNext;
+        sqlite3VtabUnlock(pVTable);
+      }
+      db->aDb[i].pVTable = 0;
+    }
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
  }
  for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
    Module *pMod = (Module *)sqliteHashData(p);
@@ -1332,6 +1343,7 @@ void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
      sqlite3BtreeClose(pDb->pBt);
      pDb->pBt = 0;
      if( j!=1 ){
+        (void)sqlite3SchemaDisconnect(db, j, 0);
        pDb->pSchema = 0;
      }
    }
@@ -3756,7 +3768,7 @@ int sqlite3_table_column_metadata(
  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
 ){
-  int rc;
+  int rc = SQLITE_OK;
  char *zErrMsg = 0;
  Table *pTab = 0;
  Column *pCol = 0;
@@ -3766,7 +3778,7 @@ int sqlite3_table_column_metadata(
  int notnull = 0;
  int primarykey = 0;
  int autoinc = 0;
-
+  int bUnlock;

 #ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
@@ -3776,14 +3788,29 @@ int sqlite3_table_column_metadata(

  /* Ensure the database schema has been loaded */
  sqlite3_mutex_enter(db->mutex);
+  bUnlock = sqlite3LockReusableSchema(db);
  sqlite3BtreeEnterAll(db);
-  rc = sqlite3Init(db, &zErrMsg);
-  if( SQLITE_OK!=rc ){
-    goto error_out;
+  if( IsSharedSchema(db)==0 ){
+    rc = sqlite3Init(db, &zErrMsg);
  }

  /* Locate the table in question */
-  pTab = sqlite3FindTable(db, zTableName, zDbName);
+  if( rc==SQLITE_OK ){
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+    Parse sParse;                   /* Fake Parse object for FindTable */
+    Parse *pSaved = db->pParse;
+    memset(&sParse, 0, sizeof(sParse));
+    db->pParse = &sParse;
+#endif
+    pTab = sqlite3FindTable(db, zTableName, zDbName);
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+    sqlite3_free(sParse.zErrMsg);
+    rc = sParse.rc;
+    db->pParse = pSaved;
+#endif
+  }
+  if( SQLITE_OK!=rc ) goto error_out;
+
  if( !pTab || IsView(pTab) ){
    pTab = 0;
    goto error_out;
@@ -3856,6 +3883,7 @@ error_out:
  sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
  sqlite3DbFree(db, zErrMsg);
  rc = sqlite3ApiExit(db, rc);
+  sqlite3UnlockReusableSchema(db, bUnlock);
  sqlite3_mutex_leave(db->mutex);
  return rc;
 }
@@ -4112,8 +4140,11 @@ int sqlite3_test_control(int op, ...){
        sqlite3ShowTriggerStepList(0);
        sqlite3ShowTrigger(0);
        sqlite3ShowTriggerList(0);
+#ifndef SQLITE_OMIT_WINDOWFUNC
        sqlite3ShowWindow(0);
        sqlite3ShowWinFunc(0);
+#endif
+        sqlite3ShowSelect(0);
      }
 #endif
      break;
@@ -776,8 +776,13 @@ void *sqlite3OomFault(sqlite3 *db){
    }
    DisableLookaside;
    if( db->pParse ){
+      Parse *pParse;
      sqlite3ErrorMsg(db->pParse, "out of memory");
      db->pParse->rc = SQLITE_NOMEM_BKPT;
+      for(pParse=db->pParse->pOuterParse; pParse; pParse = pParse->pOuterParse){
+        pParse->nErr++;
+        pParse->rc = SQLITE_NOMEM;
+      } 
    }
  }
  return 0;
@@ -5855,6 +5855,7 @@ static const char *unixTempFileDir(void){
 static int unixGetTempname(int nBuf, char *zBuf){
  const char *zDir;
  int iLimit = 0;
+  int rc = SQLITE_OK;

  /* It's odd to simulate an io-error here, but really this is just
  ** using the io-error infrastructure to test that SQLite handles this
@@ -5863,18 +5864,26 @@ static int unixGetTempname(int nBuf, char *zBuf){
  zBuf[0] = 0;
  SimulateIOError( return SQLITE_IOERR );

+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
  zDir = unixTempFileDir();
-  if( zDir==0 ) return SQLITE_IOERR_GETTEMPPATH;
-  do{
-    u64 r;
-    sqlite3_randomness(sizeof(r), &r);
-    assert( nBuf>2 );
-    zBuf[nBuf-2] = 0;
-    sqlite3_snprintf(nBuf, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX"%llx%c",
-                     zDir, r, 0);
-    if( zBuf[nBuf-2]!=0 || (iLimit++)>10 ) return SQLITE_ERROR;
-  }while( osAccess(zBuf,0)==0 );
-  return SQLITE_OK;
+  if( zDir==0 ){
+    rc = SQLITE_IOERR_GETTEMPPATH;
+  }else{
+    do{
+      u64 r;
+      sqlite3_randomness(sizeof(r), &r);
+      assert( nBuf>2 );
+      zBuf[nBuf-2] = 0;
+      sqlite3_snprintf(nBuf, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX"%llx%c",
+                       zDir, r, 0);
+      if( zBuf[nBuf-2]!=0 || (iLimit++)>10 ){
+        rc = SQLITE_ERROR;
+        break;
+      }
+    }while( osAccess(zBuf,0)==0 );
+  }
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return rc;
 }

 #if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
@@ -1918,10 +1918,12 @@ int sqlite3_win32_set_directory8(
  const char *zValue  /* New value for directory being set or reset */
 ){
  char **ppDirectory = 0;
+  int rc;
 #ifndef SQLITE_OMIT_AUTOINIT
-  int rc = sqlite3_initialize();
+  rc = sqlite3_initialize();
  if( rc ) return rc;
 #endif
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
  if( type==SQLITE_WIN32_DATA_DIRECTORY_TYPE ){
    ppDirectory = &sqlite3_data_directory;
  }else if( type==SQLITE_WIN32_TEMP_DIRECTORY_TYPE ){
@@ -1936,14 +1938,19 @@ int sqlite3_win32_set_directory8(
    if( zValue && zValue[0] ){
      zCopy = sqlite3_mprintf("%s", zValue);
      if ( zCopy==0 ){
-        return SQLITE_NOMEM_BKPT;
+        rc = SQLITE_NOMEM_BKPT;
+        goto set_directory8_done;
      }
    }
    sqlite3_free(*ppDirectory);
    *ppDirectory = zCopy;
-    return SQLITE_OK;
+    rc = SQLITE_OK;
+  }else{
+    rc = SQLITE_ERROR;
  }
-  return SQLITE_ERROR;
+set_directory8_done:
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return rc;
 }

 /*
@@ -4717,6 +4724,18 @@ static int winMakeEndInDirSep(int nBuf, char *zBuf){
  return 0;
 }

+/*
+** If sqlite3_temp_directory is not, take the mutex and return true.
+**
+** If sqlite3_temp_directory is NULL, omit the mutex and return false.
+*/
+static int winTempDirDefined(void){
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  if( sqlite3_temp_directory!=0 ) return 1;
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return 0;
+}
+
 /*
 ** Create a temporary file name and store the resulting pointer into pzBuf.
 ** The pointer returned in pzBuf must be freed via sqlite3_free().
@@ -4753,20 +4772,23 @@ static int winGetTempname(sqlite3_vfs *pVfs, char **pzBuf){
  */
  nDir = nMax - (nPre + 15);
  assert( nDir>0 );
-  if( sqlite3_temp_directory ){
+  if( winTempDirDefined() ){
    int nDirLen = sqlite3Strlen30(sqlite3_temp_directory);
    if( nDirLen>0 ){
      if( !winIsDirSep(sqlite3_temp_directory[nDirLen-1]) ){
        nDirLen++;
      }
      if( nDirLen>nDir ){
+        sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
        sqlite3_free(zBuf);
        OSTRACE(("TEMP-FILENAME rc=SQLITE_ERROR\n"));
        return winLogError(SQLITE_ERROR, 0, "winGetTempname1", 0);
      }
      sqlite3_snprintf(nMax, zBuf, "%s", sqlite3_temp_directory);
    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
  }
+
 #if defined(__CYGWIN__)
  else{
    static const char *azDirs[] = {
@@ -5555,7 +5577,7 @@ static BOOL winIsVerbatimPathname(
 ** pathname into zOut[].  zOut[] will be at least pVfs->mxPathname
 ** bytes in size.
 */
-static int winFullPathname(
+static int winFullPathnameNoMutex(
  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
  const char *zRelative,        /* Possibly relative input path */
  int nFull,                    /* Size of output buffer in bytes */
@@ -5734,6 +5756,19 @@ static int winFullPathname(
  }
 #endif
 }
+static int winFullPathname(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zRelative,        /* Possibly relative input path */
+  int nFull,                    /* Size of output buffer in bytes */
+  char *zFull                   /* Output buffer */
+){
+  int rc;
+  sqlite3_mutex *pMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR);
+  sqlite3_mutex_enter(pMutex);
+  rc = winFullPathnameNoMutex(pVfs, zRelative, nFull, zFull);
+  sqlite3_mutex_leave(pMutex);
+  return rc;
+}

 #ifndef SQLITE_OMIT_LOAD_EXTENSION
 /*
@@ -5821,6 +5821,7 @@ static int pager_open_journal(Pager *pPager){
  if( rc!=SQLITE_OK ){
    sqlite3BitvecDestroy(pPager->pInJournal);
    pPager->pInJournal = 0;
+    pPager->journalOff = 0;
  }else{
    assert( pPager->eState==PAGER_WRITER_LOCKED );
    pPager->eState = PAGER_WRITER_CACHEMOD;
@@ -7376,7 +7377,7 @@ int sqlite3PagerGetJournalMode(Pager *pPager){
 int sqlite3PagerOkToChangeJournalMode(Pager *pPager){
  assert( assert_pager_state(pPager) );
  if( pPager->eState>=PAGER_WRITER_CACHEMOD ) return 0;
-  if( NEVER(isOpen(pPager->jfd) && pPager->journalOff>0) ) return 0;
+  if( isOpen(pPager->jfd) && pPager->journalOff>0 ) return 0;
  return 1;
 }

@@ -622,14 +622,24 @@ void sqlite3PcacheClearSyncFlags(PCache *pCache){
 */
 void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
  PCache *pCache = p->pCache;
+  sqlite3_pcache_page *pOther;
  assert( p->nRef>0 );
  assert( newPgno>0 );
  assert( sqlite3PcachePageSanity(p) );
  pcacheTrace(("%p.MOVE %d -> %d\n",pCache,p->pgno,newPgno));
+  pOther = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, newPgno, 0);
+  if( pOther ){
+    PgHdr *pXPage = (PgHdr*)pOther->pExtra;
+    assert( pXPage->nRef==0 );
+    pXPage->nRef++;
+    pCache->nRefSum++;
+    sqlite3PcacheDrop(pXPage);
+  }
  sqlite3GlobalConfig.pcache2.xRekey(pCache->pCache, p->pPage, p->pgno,newPgno);
  p->pgno = newPgno;
  if( (p->flags&PGHDR_DIRTY) && (p->flags&PGHDR_NEED_SYNC) ){
    pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
+    assert( sqlite3PcachePageSanity(p) );
  }
 }

@@ -1123,23 +1123,26 @@ static void pcache1Rekey(
  PCache1 *pCache = (PCache1 *)p;
  PgHdr1 *pPage = (PgHdr1 *)pPg;
  PgHdr1 **pp;
-  unsigned int h; 
+  unsigned int hOld, hNew; 
  assert( pPage->iKey==iOld );
  assert( pPage->pCache==pCache );
+  assert( iOld!=iNew );               /* The page number really is changing */

  pcache1EnterMutex(pCache->pGroup);
-
-  h = iOld%pCache->nHash;
-  pp = &pCache->apHash[h];
+  
+  assert( pcache1FetchNoMutex(p, iOld, 0)==pPage ); /* pPg really is iOld */
+  hOld = iOld%pCache->nHash;
+  pp = &pCache->apHash[hOld];
  while( (*pp)!=pPage ){
    pp = &(*pp)->pNext;
  }
  *pp = pPage->pNext;

-  h = iNew%pCache->nHash;
+  assert( pcache1FetchNoMutex(p, iNew, 0)==0 ); /* iNew not in cache */
+  hNew = iNew%pCache->nHash;
  pPage->iKey = iNew;
-  pPage->pNext = pCache->apHash[h];
-  pCache->apHash[h] = pPage;
+  pPage->pNext = pCache->apHash[hNew];
+  pCache->apHash[hNew] = pPage;
  if( iNew>pCache->iMaxKey ){
    pCache->iMaxKey = iNew;
  }
@@ -476,7 +476,13 @@ void sqlite3Pragma(

  /* Make sure the database schema is loaded if the pragma requires that */
  if( (pPragma->mPragFlg & PragFlg_NeedSchema)!=0 ){
-    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    if( IsSharedSchema(db) && (zDb || (pPragma->mPragFlg & PragFlg_OneSchema)) ){
+      assert( iDb>=0 && iDb<db->nDb );
+      pParse->rc = sqlite3SchemaLoad(db, iDb, 0, &pParse->zErrMsg);
+      if( pParse->rc ) goto pragma_out;
+    }else{
+      if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    }
  }

  /* Register the result column names for pragmas that return results */
@@ -965,6 +971,7 @@ void sqlite3Pragma(
  **
  */
  case PragTyp_TEMP_STORE_DIRECTORY: {
+    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
    if( !zRight ){
      returnSingleText(v, sqlite3_temp_directory);
    }else{
@@ -974,6 +981,7 @@ void sqlite3Pragma(
        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
        if( rc!=SQLITE_OK || res==0 ){
          sqlite3ErrorMsg(pParse, "not a writable directory");
+          sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
          goto pragma_out;
        }
      }
@@ -991,6 +999,7 @@ void sqlite3Pragma(
      }
 #endif /* SQLITE_OMIT_WSD */
    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
    break;
  }

@@ -1009,6 +1018,7 @@ void sqlite3Pragma(
  **
  */
  case PragTyp_DATA_STORE_DIRECTORY: {
+    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
    if( !zRight ){
      returnSingleText(v, sqlite3_data_directory);
    }else{
@@ -1018,6 +1028,7 @@ void sqlite3Pragma(
        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
        if( rc!=SQLITE_OK || res==0 ){
          sqlite3ErrorMsg(pParse, "not a writable directory");
+          sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
          goto pragma_out;
        }
      }
@@ -1029,6 +1040,7 @@ void sqlite3Pragma(
      }
 #endif /* SQLITE_OMIT_WSD */
    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
    break;
  }
 #endif
@@ -2030,9 +2042,10 @@ void sqlite3Pragma(
  ** applications for any purpose.
  */
  case PragTyp_HEADER_VALUE: {
-    int iCookie = pPragma->iArg;  /* Which cookie to read or write */
+    int iCookie;                  /* Which cookie to read or write */
+    iCookie = pPragma->iArg & PRAGMA_HEADER_VALUE_MASK;     
    sqlite3VdbeUsesBtree(v, iDb);
-    if( zRight && (pPragma->mPragFlg & PragFlg_ReadOnly)==0 ){
+    if( zRight && (pPragma->iArg & PRAGMA_HEADER_VALUE_READONLY)==0 ){
      /* Write the specified cookie value */
      static const VdbeOpList setCookie[] = {
        { OP_Transaction,    0,  1,  0},    /* 0 */
@@ -56,12 +56,19 @@
 #define PragFlg_NeedSchema 0x01 /* Force schema load before running */
 #define PragFlg_NoColumns  0x02 /* OP_ResultRow called with zero columns */
 #define PragFlg_NoColumns1 0x04 /* zero columns if RHS argument is present */
-#define PragFlg_ReadOnly   0x08 /* Read-only HEADER_VALUE */
+#define PragFlg_OneSchema  0x08 /* Only a single schema required */
 #define PragFlg_Result0    0x10 /* Acts as query when no argument */
 #define PragFlg_Result1    0x20 /* Acts as query when has one argument */
 #define PragFlg_SchemaOpt  0x40 /* Schema restricts name search if present */
 #define PragFlg_SchemaReq  0x80 /* Schema required - "main" is default */

+/* For PragTyp_HEADER_VALUE pragmas the Pragma.iArg value is set
+** to the index of the header field to access (always 10 or less).
+** Ored with HEADER_VALUE_READONLY if the field is read only. */
+#define PRAGMA_HEADER_VALUE_READONLY 0x0100
+#define PRAGMA_HEADER_VALUE_MASK 0x00FF
+
+
 /* Names of columns for pragmas that return multi-column result
 ** or that return single-column results where the name of the
 ** result column is different from the name of the pragma
@@ -162,7 +169,7 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_AUTOVACUUM)
 {/* zName:     */ "auto_vacuum",
  /* ePragTyp:  */ PragTyp_AUTO_VACUUM,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1|PragFlg_OneSchema,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
 #endif
@@ -183,7 +190,7 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
 {/* zName:     */ "cache_size",
  /* ePragTyp:  */ PragTyp_CACHE_SIZE,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1|PragFlg_OneSchema,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
 #endif
@@ -244,9 +251,9 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
 {/* zName:     */ "data_version",
  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
-  /* ePragFlg:  */ PragFlg_ReadOnly|PragFlg_Result0,
+  /* ePragFlg:  */ PragFlg_Result0,
  /* ColNames:  */ 0, 0,
-  /* iArg:      */ BTREE_DATA_VERSION },
+  /* iArg:      */ BTREE_DATA_VERSION|PRAGMA_HEADER_VALUE_READONLY },
 #endif
 #if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
 {/* zName:     */ "database_list",
@@ -258,7 +265,7 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
 {/* zName:     */ "default_cache_size",
  /* ePragTyp:  */ PragTyp_DEFAULT_CACHE_SIZE,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1|PragFlg_OneSchema,
  /* ColNames:  */ 55, 1,
  /* iArg:      */ 0 },
 #endif
@@ -295,7 +302,7 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_FOREIGN_KEY)
 {/* zName:     */ "foreign_key_list",
  /* ePragTyp:  */ PragTyp_FOREIGN_KEY_LIST,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt|PragFlg_OneSchema,
  /* ColNames:  */ 0, 8,
  /* iArg:      */ 0 },
 #endif
@@ -311,9 +318,9 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
 {/* zName:     */ "freelist_count",
  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
-  /* ePragFlg:  */ PragFlg_ReadOnly|PragFlg_Result0,
+  /* ePragFlg:  */ PragFlg_Result0,
  /* ColNames:  */ 0, 0,
-  /* iArg:      */ BTREE_FREE_PAGE_COUNT },
+  /* iArg:      */ BTREE_FREE_PAGE_COUNT|PRAGMA_HEADER_VALUE_READONLY },
 #endif
 #if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
 {/* zName:     */ "full_column_names",
@@ -353,7 +360,7 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_AUTOVACUUM)
 {/* zName:     */ "incremental_vacuum",
  /* ePragTyp:  */ PragTyp_INCREMENTAL_VACUUM,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_NoColumns,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_NoColumns|PragFlg_OneSchema,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
 #endif
@@ -384,7 +391,7 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
 {/* zName:     */ "journal_mode",
  /* ePragTyp:  */ PragTyp_JOURNAL_MODE,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_OneSchema,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
 {/* zName:     */ "journal_size_limit",
@@ -422,7 +429,7 @@ static const PragmaName aPragmaName[] = {
  /* iArg:      */ 0 },
 {/* zName:     */ "max_page_count",
  /* ePragTyp:  */ PragTyp_PAGE_COUNT,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_OneSchema,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
 {/* zName:     */ "mmap_size",
@@ -450,7 +457,7 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
 {/* zName:     */ "page_count",
  /* ePragTyp:  */ PragTyp_PAGE_COUNT,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_OneSchema,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
 {/* zName:     */ "page_size",
@@ -549,14 +556,14 @@ static const PragmaName aPragmaName[] = {
 #if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS) && defined(SQLITE_DEBUG)
 {/* zName:     */ "stats",
  /* ePragTyp:  */ PragTyp_STATS,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_OneSchema,
  /* ColNames:  */ 33, 5,
  /* iArg:      */ 0 },
 #endif
 #if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
 {/* zName:     */ "synchronous",
  /* ePragTyp:  */ PragTyp_SYNCHRONOUS,
-  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1|PragFlg_OneSchema,
  /* ColNames:  */ 0, 0,
  /* iArg:      */ 0 },
 #endif
@@ -645,7 +652,7 @@ static const PragmaName aPragmaName[] = {
  /* iArg:      */ 0 },
 {/* zName:     */ "wal_checkpoint",
  /* ePragTyp:  */ PragTyp_WAL_CHECKPOINT,
-  /* ePragFlg:  */ PragFlg_NeedSchema,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_OneSchema,
  /* ColNames:  */ 50, 3,
  /* iArg:      */ 0 },
 #endif
@@ -43,6 +43,11 @@ static void corruptSchema(
    pData->rc = SQLITE_ERROR;
  }else if( db->flags & SQLITE_WriteSchema ){
    pData->rc = SQLITE_CORRUPT_BKPT;
+  }else if( IsSharedSchema(db) 
+         && 0==sqlite3StrNICmp(zExtra, "malformed database schema", 17)
+  ){
+    pData->rc = SQLITE_CORRUPT_BKPT;
+    *pData->pzErrMsg = sqlite3DbStrDup(db, zExtra);
  }else{
    char *z;
    const char *zObj = azObj[1] ? azObj[1] : "?";
@@ -53,6 +58,28 @@ static void corruptSchema(
  }
 }

+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+/*
+** Update the Schema.cksum checksum to account for the database object
+** specified by the three arguments following the first.
+*/
+static void schemaUpdateChecksum(
+  InitData *pData,                /* Schema parse context */
+  const char *zName,              /* Name of new database object */
+  const char *zRoot,              /* Root page of new database object */
+  const char *zSql                /* SQL used to create new database object */
+){
+  int i;
+  u64 cksum = pData->cksum;
+  if( zName ){
+    for(i=0; zName[i]; i++) cksum += (cksum<<3) + zName[i];
+  }
+  if( zRoot ) for(i=0; zRoot[i]; i++) cksum += (cksum<<3) + zRoot[i];
+  if( zSql ) for(i=0; zSql[i]; i++) cksum += (cksum<<3) + zSql[i];
+  pData->cksum = cksum;
+}
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+
 /*
 ** Check to see if any sibling index (another index on the same table)
 ** of pIndex has the same root page number, and if it does, return true.
@@ -76,6 +103,15 @@ static int sqlite3Prepare(
  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
  const char **pzTail       /* OUT: End of parsed string */
 );
+static int sqlite3LockAndPrepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  Vdbe *pReprepare,         /* VM being reprepared */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+);


 /*
@@ -141,7 +177,11 @@ int sqlite3InitCallback(void *pInit, int argc, char **argv, char **NotUsed){
    db->init.orphanTrigger = 0;
    db->init.azInit = (const char**)argv;
    pStmt = 0;
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+    TESTONLY(rcp = ) sqlite3LockAndPrepare(db, argv[4], -1, 0, 0, &pStmt, 0);
+#else
    TESTONLY(rcp = ) sqlite3Prepare(db, argv[4], -1, 0, 0, &pStmt, 0);
+#endif
    rc = db->errCode;
    assert( (rc&0xFF)==(rcp&0xFF) );
    db->init.iDb = saved_iDb;
@@ -153,7 +193,12 @@ int sqlite3InitCallback(void *pInit, int argc, char **argv, char **NotUsed){
        if( rc > pData->rc ) pData->rc = rc;
        if( rc==SQLITE_NOMEM ){
          sqlite3OomFault(db);
-        }else if( rc!=SQLITE_INTERRUPT && (rc&0xFF)!=SQLITE_LOCKED ){
+        }else if( rc!=SQLITE_INTERRUPT 
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+               && (rc&0xFF)!=SQLITE_LOCKED 
+               && (rc&0xFF)!=SQLITE_IOERR
+#endif
+        ){
          corruptSchema(pData, argv, sqlite3_errmsg(db));
        }
      }
@@ -184,6 +229,12 @@ int sqlite3InitCallback(void *pInit, int argc, char **argv, char **NotUsed){
      }
    }
  }
+
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  if( IsSharedSchema(db) && iDb!=1 ){
+    schemaUpdateChecksum(pData, argv[0], argv[1], argv[2]);
+  }
+#endif
  return 0;
 }

@@ -211,10 +262,28 @@ int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){

  assert( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 );
  assert( iDb>=0 && iDb<db->nDb );
-  assert( db->aDb[iDb].pSchema );
+  assert( db->aDb[iDb].pSchema || (IsSharedSchema(db) && iDb!=1) );
  assert( sqlite3_mutex_held(db->mutex) );
  assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );

+  pDb = &db->aDb[iDb];
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  assert( pDb->pSPool==0 || IsSharedSchema(db) );
+  if( pDb->pSPool ){
+    /* See if there is a free schema object in the schema-pool. If not,
+    ** disconnect from said schema pool and continue. This function will
+    ** connect to a (possibly different) schema-pool before returning. */
+    Schema *pNew = sqlite3SchemaExtract(pDb->pSPool);
+    if( pNew ){
+      pDb->pSchema = pNew;
+      return SQLITE_OK;
+    }
+    rc = sqlite3SchemaDisconnect(db, iDb, 1);
+    if( rc!=SQLITE_OK ) goto error_out;
+    assert( pDb->pSchema && pDb->pSPool==0 );
+  }
+#endif
+
  db->init.busy = 1;

  /* Construct the in-memory representation schema tables (sqlite_schema or
@@ -235,6 +304,7 @@ int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){
  initData.pzErrMsg = pzErrMsg;
  initData.mInitFlags = mFlags;
  initData.nInitRow = 0;
+  initData.cksum = 0;
  initData.mxPage = 0;
  sqlite3InitCallback(&initData, 5, (char **)azArg, 0);
  db->mDbFlags &= mask;
@@ -245,7 +315,6 @@ int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){

  /* Create a cursor to hold the database open
  */
-  pDb = &db->aDb[iDb];
  if( pDb->pBt==0 ){
    assert( iDb==1 );
    DbSetProperty(db, 1, DB_SchemaLoaded);
@@ -404,6 +473,10 @@ int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){
    rc = SQLITE_OK;
  }

+  if( rc==SQLITE_OK && iDb!=1 && IsSharedSchema(db) ){
+    rc = sqlite3SchemaConnect(db, iDb, initData.cksum);
+  }
+
  /* Jump here for an error that occurs after successfully allocating
  ** curMain and calling sqlite3BtreeEnter(). For an error that occurs
  ** before that point, jump to error_out.
@@ -425,6 +498,35 @@ error_out:
  return rc;
 }

+
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+/*
+** If this is a SHARED_SCHEMA connection and the DBFLAG_SchemaInUse flag
+** is not currently set, set it and return non-zero. Otherwise, return 0.
+*/
+int sqlite3LockReusableSchema(sqlite3 *db){
+  if( IsSharedSchema(db) && (db->mDbFlags & DBFLAG_SchemaInuse)==0 ){
+    db->mDbFlags |= DBFLAG_SchemaInuse;
+    return 1;
+  }
+  return 0;
+}
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+/*
+** This function is a no-op for non-SHARED_SCHEMA connections, or if bRelease
+** is zero. Otherwise, clear the DBFLAG_SchemaInuse flag and release all
+** schema references currently held.
+*/
+void sqlite3UnlockReusableSchema(sqlite3 *db, int bRelease){
+  if( bRelease ){
+    db->mDbFlags &= ~DBFLAG_SchemaInuse;
+    sqlite3SchemaReleaseAll(db);
+  }
+}
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+
 /*
 ** Initialize all database files - the main database file, the file
 ** used to store temporary tables, and any additional database files
@@ -435,8 +537,12 @@ error_out:
 ** bit is set in the flags field of the Db structure. 
 */
 int sqlite3Init(sqlite3 *db, char **pzErrMsg){
-  int i, rc;
+  int rc = SQLITE_OK;
+  int bReleaseSchema;
+  int i;
  int commit_internal = !(db->mDbFlags&DBFLAG_SchemaChange);
+
+  bReleaseSchema = sqlite3LockReusableSchema(db);
  
  assert( sqlite3_mutex_held(db->mutex) );
  assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );
@@ -446,20 +552,19 @@ int sqlite3Init(sqlite3 *db, char **pzErrMsg){
  /* Do the main schema first */
  if( !DbHasProperty(db, 0, DB_SchemaLoaded) ){
    rc = sqlite3InitOne(db, 0, pzErrMsg, 0);
-    if( rc ) return rc;
  }
  /* All other schemas after the main schema. The "temp" schema must be last */
-  for(i=db->nDb-1; i>0; i--){
+  for(i=db->nDb-1; rc==SQLITE_OK && i>0; i--){
    assert( i==1 || sqlite3BtreeHoldsMutex(db->aDb[i].pBt) );
    if( !DbHasProperty(db, i, DB_SchemaLoaded) ){
      rc = sqlite3InitOne(db, i, pzErrMsg, 0);
-      if( rc ) return rc;
    }
  }
-  if( commit_internal ){
+  if( rc==SQLITE_OK && commit_internal ){
    sqlite3CommitInternalChanges(db);
  }
-  return SQLITE_OK;
+  sqlite3UnlockReusableSchema(db, bReleaseSchema);
+  return rc;
 }

 /*
@@ -471,11 +576,12 @@ int sqlite3ReadSchema(Parse *pParse){
  sqlite3 *db = pParse->db;
  assert( sqlite3_mutex_held(db->mutex) );
  if( !db->init.busy ){
+    db->mDbFlags |= DBFLAG_FreeSchema;      /* For sharable-schema mode */
    rc = sqlite3Init(db, &pParse->zErrMsg);
    if( rc!=SQLITE_OK ){
      pParse->rc = rc;
      pParse->nErr++;
-    }else if( db->noSharedCache ){
+    }else if( db->noSharedCache && !IsSharedSchema(db) ){
      db->mDbFlags |= DBFLAG_SchemaKnownOk;
    }
  }
@@ -501,6 +607,10 @@ static void schemaIsValid(Parse *pParse){
    Btree *pBt = db->aDb[iDb].pBt;     /* Btree database to read cookie from */
    if( pBt==0 ) continue;

+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+    if( IsSharedSchema(db) && iDb!=1 && db->aDb[iDb].pSPool==0 ) continue;
+#endif
+
    /* If there is not already a read-only (or read-write) transaction opened
    ** on the b-tree database, open one now. If a transaction is opened, it 
    ** will be closed immediately after reading the meta-value. */
@@ -828,6 +938,7 @@ static int sqlite3LockAndPrepare(
 ){
  int rc;
  int cnt = 0;
+  int bReleaseSchema = 0;

 #ifdef SQLITE_ENABLE_API_ARMOR
  if( ppStmt==0 ) return SQLITE_MISUSE_BKPT;
@@ -837,6 +948,7 @@ static int sqlite3LockAndPrepare(
    return SQLITE_MISUSE_BKPT;
  }
  sqlite3_mutex_enter(db->mutex);
+  bReleaseSchema = sqlite3LockReusableSchema(db);
  sqlite3BtreeEnterAll(db);
  do{
    /* Make multiple attempts to compile the SQL, until it either succeeds
@@ -847,7 +959,11 @@ static int sqlite3LockAndPrepare(
    if( rc==SQLITE_OK || db->mallocFailed ) break;
  }while( (rc==SQLITE_ERROR_RETRY && (cnt++)<SQLITE_MAX_PREPARE_RETRY)
       || (rc==SQLITE_SCHEMA && (sqlite3ResetOneSchema(db,-1), cnt++)==0) );
+
  sqlite3BtreeLeaveAll(db);
+
+  sqlite3UnlockReusableSchema(db, bReleaseSchema);
+
  rc = sqlite3ApiExit(db, rc);
  assert( (rc&db->errMask)==rc );
  db->busyHandler.nBusy = 0;
@@ -803,8 +803,8 @@ void sqlite3_str_vappendf(
      case etSQLESCAPE:           /* %q: Escape ' characters */
      case etSQLESCAPE2:          /* %Q: Escape ' and enclose in '...' */
      case etSQLESCAPE3: {        /* %w: Escape " characters */
-        int i, j, k, n, isnull;
-        int needQuote;
+        i64 i, j, k, n;
+        int needQuote, isnull;
        char ch;
        char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
        char *escarg;
@@ -85,33 +85,23 @@ static void resolveAlias(
    sqlite3ExprDelete(db, pDup);
    pDup = 0;
  }else{
+    Expr temp;
    incrAggFunctionDepth(pDup, nSubquery);
    if( pExpr->op==TK_COLLATE ){
      assert( !ExprHasProperty(pExpr, EP_IntValue) );
      pDup = sqlite3ExprAddCollateString(pParse, pDup, pExpr->u.zToken);
    }
-
-    /* Before calling sqlite3ExprDelete(), set the EP_Static flag. This 
-    ** prevents ExprDelete() from deleting the Expr structure itself,
-    ** allowing it to be repopulated by the memcpy() on the following line.
-    ** The pExpr->u.zToken might point into memory that will be freed by the
-    ** sqlite3DbFree(db, pDup) on the last line of this block, so be sure to
-    ** make a copy of the token before doing the sqlite3DbFree().
-    */
-    ExprSetProperty(pExpr, EP_Static);
-    sqlite3ExprDelete(db, pExpr);
-    memcpy(pExpr, pDup, sizeof(*pExpr));
-    if( !ExprHasProperty(pExpr, EP_IntValue) && pExpr->u.zToken!=0 ){
-      assert( (pExpr->flags & (EP_Reduced|EP_TokenOnly))==0 );
-      pExpr->u.zToken = sqlite3DbStrDup(db, pExpr->u.zToken);
-      pExpr->flags |= EP_MemToken;
-    }
+    memcpy(&temp, pDup, sizeof(Expr));
+    memcpy(pDup, pExpr, sizeof(Expr));
+    memcpy(pExpr, &temp, sizeof(Expr));
    if( ExprHasProperty(pExpr, EP_WinFunc) ){
      if( ALWAYS(pExpr->y.pWin!=0) ){
        pExpr->y.pWin->pOwner = pExpr;
      }
    }
-    sqlite3DbFree(db, pDup);
+    sqlite3ParserAddCleanup(pParse,
+      (void(*)(sqlite3*,void*))sqlite3ExprDelete,
+      pDup);
  }
 }

@@ -314,7 +304,7 @@ static int lookupName(
        pTab = pItem->pTab;
        assert( pTab!=0 && pTab->zName!=0 );
        assert( pTab->nCol>0 || pParse->nErr );
-        assert( pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
+        assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
        if( pItem->fg.isNestedFrom ){
          /* In this case, pItem is a subquery that has been formed from a
          ** parenthesized subset of the FROM clause terms.  Example:
@@ -324,7 +324,7 @@ int sqlite3ColumnIndex(Table *pTab, const char *zCol){
 */
 void sqlite3SrcItemColumnUsed(SrcItem *pItem, int iCol){
  assert( pItem!=0 );
-  assert( pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
+  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
  if( pItem->fg.isNestedFrom ){
    ExprList *pResults;
    assert( pItem->pSelect!=0 );
@@ -1688,7 +1688,7 @@ static void generateSortTail(
    if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
    addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
    VdbeCoverage(v);
-    codeOffset(v, p->iOffset, addrContinue);
+    assert( p->iLimit==0 && p->iOffset==0 );
    sqlite3VdbeAddOp3(v, OP_SorterData, iTab, regSortOut, iSortTab);
    bSeq = 0;
  }else{
@@ -1696,6 +1696,9 @@ static void generateSortTail(
    codeOffset(v, p->iOffset, addrContinue);
    iSortTab = iTab;
    bSeq = 1;
+    if( p->iOffset>0 ){
+      sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
+    }
  }
  for(i=0, iCol=nKey+bSeq-1; i<nColumn; i++){
 #ifdef SQLITE_ENABLE_SORTER_REFERENCES
@@ -3688,10 +3691,11 @@ static int multiSelectOrderBy(
  */
  sqlite3VdbeResolveLabel(v, labelEnd);

-  /* Reassembly the compound query so that it will be freed correctly
+  /* Reassemble the compound query so that it will be freed correctly
  ** by the calling function */
  if( pSplit->pPrior ){
-    sqlite3SelectDelete(db, pSplit->pPrior);
+    sqlite3ParserAddCleanup(pParse, 
+       (void(*)(sqlite3*,void*))sqlite3SelectDelete, pSplit->pPrior);
  }
  pSplit->pPrior = pPrior;
  pPrior->pNext = pSplit;
@@ -4122,6 +4126,9 @@ static void renumberCursors(
 **              (17d2) DISTINCT
 **        (17e) the subquery may not contain window functions, and
 **        (17f) the subquery must not be the RHS of a LEFT JOIN.
+**        (17g) either the subquery is the first element of the outer
+**              query or there are no RIGHT or FULL JOINs in any arm
+**              of the subquery.  (This is a duplicate of condition (27b).)
 **
 **        The parent and sub-query may contain WHERE clauses. Subject to
 **        rules (11), (13) and (14), they may also contain ORDER BY,
@@ -4173,7 +4180,11 @@ static void renumberCursors(
 **        See also (3) for restrictions on LEFT JOIN.
 **
 **  (27)  The subquery may not contain a FULL or RIGHT JOIN unless it
-**        is the first element of the parent query.
+**        is the first element of the parent query.  This must be the
+**        the case if:
+**        (27a) the subquery is not compound query, and
+**        (27b) the subquery is a compound query and the RIGHT JOIN occurs
+**              in any arm of the compound query.  (See also (17g).)
 **
 **  (28)  The subquery is not a MATERIALIZED CTE.
 **
@@ -4303,7 +4314,7 @@ static int flattenSubquery(

  assert( pSubSrc->nSrc>0 );  /* True by restriction (7) */
  if( iFrom>0 && (pSubSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
-    return 0;   /* Restriction (27) */
+    return 0;   /* Restriction (27a) */
  }
  if( pSubitem->fg.isCte && pSubitem->u2.pCteUse->eM10d==M10d_Yes ){
    return 0;       /* (28) */
@@ -4323,7 +4334,7 @@ static int flattenSubquery(
  **          NATURAL join or a join that as an ON or USING clause.
  **
  ** These conditions are sufficient to keep an EP_OuterON from being
-  ** flattened into an EP_InnerON.  Restrictions (3a) and (27) prevent
+  ** flattened into an EP_InnerON.  Restrictions (3a) and (27a) prevent
  ** an EP_InnerON from being flattened into an EP_OuterON.
  */
  if( pSubSrc->nSrc>=2
@@ -4365,6 +4376,12 @@ static int flattenSubquery(
      ){
        return 0;
      }
+      if( iFrom>0 && (pSub1->pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+        /* Without this restriction, the JT_LTORJ flag would end up being
+        ** omitted on left-hand tables of the right join that is being
+        ** flattened. */
+        return 0;   /* Restrictions (17g), (27b) */
+      }
      testcase( pSub1->pSrc->nSrc>1 );
    }

@@ -5197,6 +5214,7 @@ static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
   || p->pSrc->nSrc!=1
   || p->pSrc->a[0].pSelect
   || pAggInfo->nFunc!=1
+   || p->pHaving
  ){
    return 0;
  }
@@ -5898,7 +5916,7 @@ static int selectExpander(Walker *pWalker, Select *p){
            zTabName = pTab->zName;
          }
          if( db->mallocFailed ) break;
-          assert( pFrom->fg.isNestedFrom == IsNestedFrom(pFrom->pSelect) );
+          assert( (int)pFrom->fg.isNestedFrom == IsNestedFrom(pFrom->pSelect) );
          if( pFrom->fg.isNestedFrom ){
            assert( pFrom->pSelect!=0 );
            pNestedFrom = pFrom->pSelect->pEList;
@@ -6827,7 +6845,9 @@ int sqlite3Select(
    ){
      SELECTTRACE(0x100,pParse,p,
                ("omit superfluous ORDER BY on %r FROM-clause subquery\n",i+1));
-      sqlite3ExprListDelete(db, pSub->pOrderBy);
+      sqlite3ParserAddCleanup(pParse, 
+         (void(*)(sqlite3*,void*))sqlite3ExprListDelete,
+         pSub->pOrderBy);
      pSub->pOrderBy = 0;
    }

@@ -1184,13 +1184,14 @@ static ShellState shellState;

 /* Allowed values for ShellState.openMode
 */
-#define SHELL_OPEN_UNSPEC      0      /* No open-mode specified */
-#define SHELL_OPEN_NORMAL      1      /* Normal database file */
-#define SHELL_OPEN_APPENDVFS   2      /* Use appendvfs */
-#define SHELL_OPEN_ZIPFILE     3      /* Use the zipfile virtual table */
-#define SHELL_OPEN_READONLY    4      /* Open a normal database read-only */
-#define SHELL_OPEN_DESERIALIZE 5      /* Open using sqlite3_deserialize() */
-#define SHELL_OPEN_HEXDB       6      /* Use "dbtotxt" output as data source */
+#define SHELL_OPEN_UNSPEC       0     /* No open-mode specified */
+#define SHELL_OPEN_NORMAL       1     /* Normal database file */
+#define SHELL_OPEN_APPENDVFS    2     /* Use appendvfs */
+#define SHELL_OPEN_ZIPFILE      3     /* Use the zipfile virtual table */
+#define SHELL_OPEN_READONLY     4     /* Open a normal database read-only */
+#define SHELL_OPEN_DESERIALIZE  5     /* Open using sqlite3_deserialize() */
+#define SHELL_OPEN_HEXDB        6     /* Use "dbtotxt" output as data source */
+#define SHELL_OPEN_SHAREDSCHEMA 7     /* Open for schema reuse */

 /* Allowed values for ShellState.eTraceType
 */
@@ -4490,6 +4491,12 @@ static const char *(azHelp[]) = {
  "      --sha3-384            Use the sha3-384 algorithm",
  "      --sha3-512            Use the sha3-512 algorithm",
  "    Any other argument is a LIKE pattern for tables to hash",
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_ENABLE_DBPAGE_VTAB)
+  ".shared-schema CMD DB1 DB2 ...",
+  "    Commands:",
+  "       check                Determine if DB1, DB2, etc have identical schemas",
+  "       fix                  Attempt to make DB1, DB2, etc compatible",
+#endif
 #if !defined(SQLITE_NOHAVE_SYSTEM) && !defined(SQLITE_SHELL_WASM_MODE)
  ".shell CMD ARGS...       Run CMD ARGS... in a system shell",
 #endif
@@ -5030,6 +5037,11 @@ static void open_db(ShellState *p, int openFlags){
            SQLITE_OPEN_READONLY|p->openFlags, 0);
        break;
      }
+      case SHELL_OPEN_SHAREDSCHEMA: {
+        sqlite3_open_v2(p->pAuxDb->zDbFilename, &p->db,
+          SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_SHARED_SCHEMA,0);
+        break;
+      }
      case SHELL_OPEN_UNSPEC:
      case SHELL_OPEN_NORMAL: {
        sqlite3_open_v2(zDbFilename, &p->db,
@@ -7300,6 +7312,237 @@ static char *shellMPrintf(int *pRc, const char *zFmt, ...){
  }
  return z;
 }
+static int sharedSchemaFix(ShellState *pState, const char *zDb, int eFix){
+  int rc = SQLITE_OK;
+  i64 iLast = 0;
+  int iCookie = 0;
+  int iAutoVacuum = 0;
+  sqlite3_stmt *pStmt = 0;
+
+  shellExecPrintf(pState->db, &rc, "ATTACH '%q' AS _shared_schema_tmp", zDb);
+  shellExecPrintf(pState->db, &rc, "PRAGMA writable_schema = 1");
+  shellExecPrintf(pState->db, &rc, "BEGIN");
+  shellPreparePrintf(pState->db, &rc, &pStmt, 
+      "SELECT max(rowid) FROM _shared_schema_tmp.sqlite_master"
+  );
+  sqlite3_step(pStmt);
+  iLast = sqlite3_column_int64(pStmt, 0);
+  shellFinalize(&rc, pStmt);
+  shellPreparePrintf(pState->db, &rc, &pStmt,
+      "INSERT INTO _shared_schema_tmp.sqlite_master SELECT "
+      "  type, name, tbl_name, ("
+      "    SELECT rootpage FROM _shared_schema_tmp.sqlite_master WHERE "
+      "      type IS o.type AND name IS o.name AND rowid<=?"
+      "  ), sql FROM main.sqlite_master AS o"
+  );
+  sqlite3_bind_int64(pStmt, 1, iLast);
+  sqlite3_step(pStmt);
+  shellFinalize(&rc, pStmt);
+
+  shellExecPrintf(pState->db, &rc,
+      "DELETE FROM _shared_schema_tmp.sqlite_master WHERE rowid<=%lld",
+      iLast
+  );
+  shellExecPrintf(pState->db, &rc, "COMMIT");
+  sqlite3_exec(pState->db, "PRAGMA writable_schema = 0", 0, 0, 0);
+
+  /* Copy the auto-vacuum setting from main to the target db */
+  shellPreparePrintf(pState->db, &rc, &pStmt, "PRAGMA main.auto_vacuum");
+  sqlite3_step(pStmt);
+  iAutoVacuum = sqlite3_column_int(pStmt, 0);
+  shellFinalize(&rc, pStmt);
+  shellExecPrintf(pState->db, &rc, 
+      "PRAGMA _shared_schema_tmp.auto_vacuum = %d", iAutoVacuum
+  );
+
+  /* Vacuum the db in order to standardize the rootpage numbers. */
+  shellExecPrintf(pState->db, &rc, "VACUUM _shared_schema_tmp");
+
+  /* Set the schema-cookie value to the same as database "main" */
+  shellPreparePrintf(pState->db, &rc, &pStmt, "PRAGMA main.schema_version");
+  sqlite3_step(pStmt);
+  iCookie = sqlite3_column_int(pStmt, 0);
+  shellFinalize(&rc, pStmt);
+  shellExecPrintf(pState->db, &rc, 
+      "PRAGMA _shared_schema_tmp.schema_version = %d", iCookie
+  );
+
+  sqlite3_exec(pState->db, "DETACH _shared_schema_tmp", 0, 0, 0);
+  return rc;
+}
+
+static int sharedSchemaCheck(ShellState *pState, const char *zDb, int *peFix){
+  int rc = SQLITE_OK;
+  int bFailed = 0;
+  sqlite3_stmt *pStmt = 0;
+
+  if( peFix ) *peFix = 0;
+  shellExecPrintf(pState->db, &rc, "ATTACH '%q' AS _shared_schema_tmp", zDb);
+
+  /* Check if this database has the same set of objects as the current db */
+  shellPreparePrintf(pState->db, &rc, &pStmt, 
+    "SELECT type, name FROM _shared_schema_tmp.sqlite_master AS o "
+    "WHERE NOT EXISTS ("
+    "  SELECT 1 FROM main.sqlite_master "
+    "    WHERE name IS o.name AND type IS o.type"
+    ")"
+    " UNION ALL "
+    "SELECT type, name FROM main.sqlite_master AS o "
+    "WHERE NOT EXISTS ("
+    "  SELECT 1 FROM _shared_schema_tmp.sqlite_master "
+    "    WHERE name IS o.name AND type IS o.type"
+    ")"
+  );
+  if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+    utf8_printf(pState->out, "%s is NOT compatible (objects)\n", zDb);
+    bFailed = 1;
+  }
+  shellFinalize(&rc, pStmt);
+
+  /* Check if this database has the same set of SQL statements as the 
+  ** current db. */
+  if( bFailed==0 ){
+    shellPreparePrintf(pState->db, &rc, &pStmt, 
+        "SELECT 1 FROM _shared_schema_tmp.sqlite_master AS o "
+        "WHERE sql IS NOT ("
+        "  SELECT sql FROM main.sqlite_master "
+        "    WHERE name IS o.name AND type IS o.type"
+        ")"
+    );
+    if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      utf8_printf(pState->out, "%s is NOT compatible (SQL)\n", zDb);
+      bFailed = 1;
+    }
+    shellFinalize(&rc, pStmt);
+  }
+
+  /* Check if this database has the same set of root pages as the current 
+  ** db. */
+  if( bFailed==0 ){
+    shellPreparePrintf(pState->db, &rc, &pStmt, 
+        "SELECT 1 FROM _shared_schema_tmp.sqlite_master AS o "
+        "WHERE rootpage IS NOT ("
+        "  SELECT rootpage FROM main.sqlite_master "
+        "    WHERE name IS o.name AND type IS o.type"
+        ")"
+    );
+    if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      if( peFix==0 ){
+        utf8_printf(pState->out, "%s is NOT compatible (root pages)\n", zDb);
+      }
+      bFailed = 1;
+      if( peFix ) *peFix = 1;
+    }
+    shellFinalize(&rc, pStmt);
+  }
+
+  if( bFailed==0 ){
+    shellPreparePrintf(pState->db, &rc, &pStmt, 
+        "SELECT 1 WHERE ("
+        "  SELECT group_concat(rootpage || '.' || name || '.' || sql, '.') "
+        "  FROM _shared_schema_tmp.sqlite_master"
+        ") IS NOT ("
+        "  SELECT group_concat(rootpage || '.' || name || '.' || sql, '.') "
+        "  FROM main.sqlite_master"
+        ")"
+    );
+    if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      if( peFix==0 ){
+        utf8_printf(pState->out, 
+            "%s is NOT compatible (order of sqlite_master rows)\n", zDb
+        );
+      }
+      bFailed = 1;
+      if( peFix ) *peFix = 2;
+    }
+    shellFinalize(&rc, pStmt);
+  }
+
+  if( bFailed==0 ){
+    int iMain = -1;
+    int iNew = +1;
+    shellPreparePrintf(pState->db, &rc, &pStmt, 
+        "PRAGMA main.schema_version"
+    );
+    if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      iMain = sqlite3_column_int(pStmt, 0);
+    }
+    shellFinalize(&rc, pStmt);
+    shellPreparePrintf(pState->db, &rc, &pStmt, 
+        "PRAGMA _shared_schema_tmp.schema_version"
+    );
+    if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      iNew = sqlite3_column_int(pStmt, 0);
+    }
+    shellFinalize(&rc, pStmt);
+    if( rc==SQLITE_OK && iMain!=iNew ){
+      if( peFix==0 ){
+        utf8_printf(pState->out, 
+            "%s is NOT compatible (schema cookie)\n", zDb
+        );
+      }
+      bFailed = 1;
+      if( peFix ) *peFix = 3;
+    }
+  }
+
+  if( rc==SQLITE_OK && bFailed==0 ){
+    utf8_printf(pState->out, "%s is compatible\n", zDb);
+  }
+
+  sqlite3_exec(pState->db, "DETACH _shared_schema_tmp", 0, 0, 0);
+  return rc;
+}
+
+/*
+** .shared-schema check|fix DB1 DB2...
+*/
+static int sharedSchemaDotCommand(
+  ShellState *pState,             /* Current shell tool state */
+  char **azArg,                   /* Array of arguments passed to dot command */
+  int nArg                        /* Number of entries in azArg[] */
+){
+  int rc = SQLITE_OK;
+  int bFix = 0;                   /* Fix databases if possible */
+  int n1;
+  int i;
+  if( nArg<3 ){
+    goto shared_schema_usage;
+  }
+
+  n1 = (int)strlen(azArg[1]);
+  if( n1>0 && n1<=3 && memcmp("fix", azArg[1], n1)==0 ){
+    bFix = 1;
+  }else if( n1==0 || n1>5 || memcmp("check", azArg[1], n1) ){
+    goto shared_schema_usage;
+  }
+
+  for(i=2; rc==SQLITE_OK && i<nArg; i++){
+    int eFix = 0;
+    rc = sharedSchemaCheck(pState, azArg[i], bFix ? &eFix : 0);
+    if( rc==SQLITE_OK && bFix && eFix ){
+      utf8_printf(pState->out, "Fixing %s... ", azArg[i]);
+      fflush(pState->out);
+      rc = sharedSchemaFix(pState, azArg[i], eFix);
+      if( rc==SQLITE_OK ){
+        rc = sharedSchemaCheck(pState, azArg[i], &eFix);
+        if( rc==SQLITE_OK && eFix ){
+          utf8_printf(pState->out, "VACUUMing main... ");
+          fflush(pState->out);
+          rc = sqlite3_exec(pState->db, "VACUUM main", 0, 0, 0);
+          if( rc==SQLITE_OK ){
+            rc = sharedSchemaCheck(pState, azArg[i], 0);
+          }
+        }
+      }
+    }
+  }
+
+  return rc;
+ shared_schema_usage:
+  raw_printf(stderr, "usage: .shared-schema check|fix DB1 DB2...\n");
+  return SQLITE_ERROR;
+}


 /*
@@ -10678,6 +10921,13 @@ static int do_meta_command(char *zLine, ShellState *p){
    sqlite3_free(zSql);
  }else

+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_ENABLE_DBPAGE_VTAB)
+  if( c=='s' && strncmp(azArg[0], "shared-schema", n)==0 ){
+    open_db(p, 0);
+    sharedSchemaDotCommand(p, azArg, nArg);
+  }else
+#endif
+
 #if !defined(SQLITE_NOHAVE_SYSTEM) && !defined(SQLITE_SHELL_WASM_MODE)
  if( c=='s'
   && (strncmp(azArg[0], "shell", n)==0 || strncmp(azArg[0],"system",n)==0)
@@ -11990,7 +12240,7 @@ int SQLITE_CDECL wmain(int argc, wchar_t **wargv){
  char **argv;
 #endif
 #ifdef SQLITE_DEBUG
-  sqlite3_uint64 mem_main_enter = sqlite3_memory_used();
+  sqlite3_int64 mem_main_enter = sqlite3_memory_used();
 #endif
  char *zErrMsg = 0;
 #ifdef SQLITE_SHELL_WASM_MODE
@@ -12218,6 +12468,8 @@ int SQLITE_CDECL wmain(int argc, wchar_t **wargv){
 #endif
    }else if( strcmp(z,"-readonly")==0 ){
      data.openMode = SHELL_OPEN_READONLY;
+    }else if( strcmp(z,"-sharedschema")==0 ){
+      data.openMode = SHELL_OPEN_SHAREDSCHEMA;
    }else if( strcmp(z,"-nofollow")==0 ){
      data.openFlags = SQLITE_OPEN_NOFOLLOW;
 #if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_HAVE_ZLIB)
@@ -12342,6 +12594,8 @@ int SQLITE_CDECL wmain(int argc, wchar_t **wargv){
 #endif
    }else if( strcmp(z,"-readonly")==0 ){
      data.openMode = SHELL_OPEN_READONLY;
+    }else if( strcmp(z,"-sharedschema")==0 ){
+      data.openMode = SHELL_OPEN_SHAREDSCHEMA;
    }else if( strcmp(z,"-nofollow")==0 ){
      data.openFlags |= SQLITE_OPEN_NOFOLLOW;
    }else if( strcmp(z,"-ascii")==0 ){
@@ -612,10 +612,11 @@ int sqlite3_exec(
 #define SQLITE_OPEN_EXRESCODE        0x02000000  /* Extended result codes */

 /* Reserved:                         0x00F00000 */
+#define SQLITE_OPEN_SHARED_SCHEMA    0x01000000  /* Ok for sqlite3_open_v2() */
+
 /* Legacy compatibility: */
 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */

-
 /*
 ** CAPI3REF: Device Characteristics
 **
@@ -6282,7 +6283,7 @@ sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
 **
 ** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
 ** for the N-th database on database connection D, or a NULL pointer of N is
-** out of range.  An N alue of 0 means the main database file.  An N of 1 is
+** out of range.  An N value of 0 means the main database file.  An N of 1 is
 ** the "temp" schema.  Larger values of N correspond to various ATTACH-ed
 ** databases.
 **
@@ -198,6 +198,11 @@
 */
 #include "sqlite3.h"

+/*
+** Reuse the STATIC_LRU for mutex access to sqlite3_temp_directory.
+*/
+#define SQLITE_MUTEX_STATIC_TEMPDIR SQLITE_MUTEX_STATIC_VFS1
+
 /*
 ** Include the configuration header output by 'configure' if we're using the
 ** autoconf-based build
@@ -1176,6 +1181,7 @@ typedef struct CteUse CteUse;
 typedef struct Db Db;
 typedef struct DbFixer DbFixer;
 typedef struct Schema Schema;
+typedef struct SchemaPool SchemaPool;
 typedef struct Expr Expr;
 typedef struct ExprList ExprList;
 typedef struct FKey FKey;
@@ -1314,6 +1320,10 @@ struct Db {
  u8 safety_level;     /* How aggressive at syncing data to disk */
  u8 bSyncSet;         /* True if "PRAGMA synchronous=N" has been run */
  Schema *pSchema;     /* Pointer to database schema (possibly shared) */
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  SchemaPool *pSPool;  /* For REUSE_SCHEMA mode */
+  VTable *pVTable;     /* List of all VTable objects (REUSE_SCHEMA mode only) */
+#endif
 };

 /*
@@ -1345,6 +1355,9 @@ struct Schema {
  u8 enc;              /* Text encoding used by this database */
  u16 schemaFlags;     /* Flags associated with this schema */
  int cache_size;      /* Number of pages to use in the cache */
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  Schema *pNext;       /* Next Schema object SchemaPool (REUSE_SCHEMA) */
+#endif
 };

 /*
@@ -1669,6 +1682,12 @@ struct sqlite3 {
 #endif
 };

+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+# define IsSharedSchema(db) (((db)->openFlags & SQLITE_OPEN_SHARED_SCHEMA)!=0)
+#else
+# define IsSharedSchema(db) 0
+#endif
+
 /*
 ** A macro to discover the encoding of a database.
 */
@@ -1750,6 +1769,9 @@ struct sqlite3 {
 #define DBFLAG_InternalFunc   0x0020  /* Allow use of internal functions */
 #define DBFLAG_EncodingFixed  0x0040  /* No longer possible to change enc. */

+#define DBFLAG_SchemaInuse    0x0080  /* Do not release sharable schemas */
+#define DBFLAG_FreeSchema     0x0100  /* Free extra shared schemas on release */
+
 /*
 ** Bits of the sqlite3.dbOptFlags field that are used by the
 ** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
@@ -2249,6 +2271,9 @@ struct VTable {
  u8 eVtabRisk;             /* Riskiness of allowing hacker access */
  int iSavepoint;           /* Depth of the SAVEPOINT stack */
  VTable *pNext;            /* Next in linked list (see above) */
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  char *zName;              /* Table name (REUSE_SCHEMA mode) */
+#endif
 };

 /* Allowed values for VTable.eVtabRisk
@@ -3799,6 +3824,9 @@ struct Trigger {
  Schema *pTabSchema;     /* Schema containing the table */
  TriggerStep *step_list; /* Link list of trigger program steps             */
  Trigger *pNext;         /* Next trigger associated with the table */
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  char *zTabSchema;       /* Temp triggers in IsSharedSchema() dbs only */
+#endif
 };

 /*
@@ -3915,6 +3943,7 @@ typedef struct {
  int rc;             /* Result code stored here */
  u32 mInitFlags;     /* Flags controlling error messages */
  u32 nInitRow;       /* Number of rows processed */
+  u64 cksum;          /* Schema checksum for REUSE_SCHEMA mode */
  Pgno mxPage;        /* Maximum page number.  0 for no limit. */
 } InitData;

@@ -4474,6 +4503,7 @@ char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
  void sqlite3TreeViewSelect(TreeView*, const Select*, u8);
  void sqlite3TreeViewWith(TreeView*, const With*, u8);
  void sqlite3TreeViewUpsert(TreeView*, const Upsert*, u8);
+#if TREETRACE_ENABLED
  void sqlite3TreeViewDelete(const With*, const SrcList*, const Expr*,
                             const ExprList*,const Expr*, const Trigger*);
  void sqlite3TreeViewInsert(const With*, const SrcList*,
@@ -4482,6 +4512,7 @@ char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
  void sqlite3TreeViewUpdate(const With*, const SrcList*, const ExprList*,
                             const Expr*, int, const ExprList*, const Expr*,
                             const Upsert*, const Trigger*);
+#endif
 #ifndef SQLITE_OMIT_TRIGGER
  void sqlite3TreeViewTriggerStep(TreeView*, const TriggerStep*, u8, u8);
  void sqlite3TreeViewTrigger(TreeView*, const Trigger*, u8, u8);
@@ -5064,6 +5095,29 @@ void sqlite3DefaultRowEst(Index*);
 void sqlite3RegisterLikeFunctions(sqlite3*, int);
 int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
 void sqlite3SchemaClear(void *);
+void sqlite3SchemaClearOrDisconnect(sqlite3*, int);
+
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA 
+int sqlite3SchemaConnect(sqlite3*, int, u64);
+int sqlite3SchemaDisconnect(sqlite3 *, int, int);
+Schema *sqlite3SchemaExtract(SchemaPool*);
+int sqlite3SchemaLoad(sqlite3*, int, int*, char**);
+void sqlite3SchemaReleaseAll(sqlite3*);
+void sqlite3SchemaRelease(sqlite3*, int);
+void sqlite3SchemaAdjustUsed(sqlite3*, int, int, int*);
+void sqlite3SchemaWritable(Parse*, int);
+void sqlite3UnlockReusableSchema(sqlite3 *db, int bRelease);
+int sqlite3LockReusableSchema(sqlite3 *db);
+#else
+# define sqlite3SchemaWritable(x,y)
+# define sqlite3UnlockReusableSchema(x,y)
+# define sqlite3LockReusableSchema(x) 0
+# define sqlite3SchemaDisconnect(x,y,z) SQLITE_OK
+# define sqlite3SchemaLoad(w,x,y,z) SQLITE_OK
+# define sqlite3SchemaRelease(y,z)
+# define sqlite3SchemaConnect(x,y,z) SQLITE_OK
+#endif
+
 Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
 int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
 KeyInfo *sqlite3KeyInfoAlloc(sqlite3*,int,int);
@@ -288,11 +288,24 @@ int sqlite3_db_status(
    case SQLITE_DBSTATUS_SCHEMA_USED: {
      int i;                      /* Used to iterate through schemas */
      int nByte = 0;              /* Used to accumulate return value */
+      int bReleaseSchema;

      sqlite3BtreeEnterAll(db);
+      bReleaseSchema = sqlite3LockReusableSchema(db);
      db->pnBytesFreed = &nByte;
      for(i=0; i<db->nDb; i++){
-        Schema *pSchema = db->aDb[i].pSchema;
+        Schema *pSchema;
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+        int bUnload = 0;
+        int nUsed = nByte;
+        if( db->aDb[i].pSPool ){
+          char *zDummy = 0;
+          rc = sqlite3SchemaLoad(db, i, &bUnload, &zDummy);
+          sqlite3_free(zDummy);
+          if( rc ) break;
+        }
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+        pSchema = db->aDb[i].pSchema;
        if( ALWAYS(pSchema!=0) ){
          HashElem *p;

@@ -314,7 +327,14 @@ int sqlite3_db_status(
            sqlite3DeleteTable(db, (Table *)sqliteHashData(p));
          }
        }
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+        if( db->aDb[i].pSPool ){
+          if( bUnload ) sqlite3SchemaRelease(db, i);
+          sqlite3SchemaAdjustUsed(db, i, nUsed, &nByte);
+        }
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
      }
+      sqlite3UnlockReusableSchema(db, bReleaseSchema);
      db->pnBytesFreed = 0;
      sqlite3BtreeLeaveAll(db);

@@ -3705,6 +3705,9 @@ static int sqliteCmdUsage(
    "HANDLE ?FILENAME? ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN?"
    " ?-nofollow BOOLEAN?"
    " ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN?"
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+    " ?-shared-schema BOOLEAN?"
+#endif
  );
  return TCL_ERROR;
 }
@@ -3836,6 +3839,16 @@ static int SQLITE_TCLAPI DbMain(
      }else{
        flags &= ~SQLITE_OPEN_URI;
      }
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+    }else if( strcmp(zArg, "-shared-schema")==0 ){
+      int b;
+      if( Tcl_GetBooleanFromObj(interp, objv[i], &b) ) return TCL_ERROR;
+      if( b ){
+        flags |= SQLITE_OPEN_SHARED_SCHEMA;
+      }else{
+        flags &= ~SQLITE_OPEN_SHARED_SCHEMA;
+      }
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
    }else if( strcmp(zArg, "-translatefilename")==0 ){
      if( Tcl_GetBooleanFromObj(interp, objv[i], &bTranslateFileName) ){
        return TCL_ERROR;
@@ -783,6 +783,12 @@ Tcl_SetVar2(interp, "sqlite_options", "mergesort", "1", TCL_GLOBAL_ONLY);
  Tcl_SetVar2(interp, "sqlite_options", "windowfunc", "1", TCL_GLOBAL_ONLY);
 #endif

+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  Tcl_SetVar2(interp, "sqlite_options", "sharedschema", "1", TCL_GLOBAL_ONLY);
+#else
+  Tcl_SetVar2(interp, "sqlite_options", "sharedschema", "0", TCL_GLOBAL_ONLY);
+#endif
+
 #define LINKVAR(x) { \
    static const int cv_ ## x = SQLITE_ ## x; \
    Tcl_LinkVar(interp, "SQLITE_" #x, (char *)&(cv_ ## x), \
@@ -0,0 +1,282 @@
+/*
+** 2006 June 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Code for testing the virtual table interfaces.  This code
+** is not included in the SQLite library.  It is used for automated
+** testing of the SQLite library.
+*/
+
+/*
+** None of this works unless we have virtual tables.
+*/
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_TEST)
+
+#include <tcl.h>
+
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+
+#include "sqliteInt.h"
+
+/* The code in this file defines a sqlite3 virtual-table module with
+** the following schema.
+*/
+#define SCHEMAPOOL_SCHEMA \
+"CREATE TABLE x("         \
+"  cksum   INTEGER, "     \
+"  nref    INTEGER, "     \
+"  nschema INTEGER, "     \
+"  ndelete INTEGER  "     \
+")"
+
+#define SCHEMAPOOL_NFIELD 4
+
+typedef struct schemapool_vtab schemapool_vtab;
+typedef struct schemapool_cursor schemapool_cursor;
+
+/* A schema table object */
+struct schemapool_vtab {
+  sqlite3_vtab base;
+};
+
+/* A schema table cursor object */
+struct schemapool_cursor {
+  sqlite3_vtab_cursor base;
+  sqlite3_int64 *aData;
+  int iRow;
+  int nRow;
+};
+
+/*
+** Table destructor for the schema module.
+*/
+static int schemaPoolDestroy(sqlite3_vtab *pVtab){
+  sqlite3_free(pVtab);
+  return 0;
+}
+
+/*
+** Table constructor for the schema module.
+*/
+static int schemaPoolCreate(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  int rc = SQLITE_NOMEM;
+  schemapool_vtab *pVtab = sqlite3_malloc(sizeof(schemapool_vtab));
+  if( pVtab ){
+    memset(pVtab, 0, sizeof(schemapool_vtab));
+    rc = sqlite3_declare_vtab(db, SCHEMAPOOL_SCHEMA);
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(pVtab);
+      pVtab = 0;
+    }
+  }
+  *ppVtab = (sqlite3_vtab *)pVtab;
+  return rc;
+}
+
+/*
+** Open a new cursor on the schema table.
+*/
+static int schemaPoolOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  int rc = SQLITE_NOMEM;
+  schemapool_cursor *pCur;
+  pCur = sqlite3_malloc(sizeof(schemapool_cursor));
+  if( pCur ){
+    memset(pCur, 0, sizeof(schemapool_cursor));
+    *ppCursor = (sqlite3_vtab_cursor*)pCur;
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+
+/*
+** Close a schema table cursor.
+*/
+static int schemaPoolClose(sqlite3_vtab_cursor *cur){
+  schemapool_cursor *pCur = (schemapool_cursor*)cur;
+  sqlite3_free(pCur->aData);
+  sqlite3_free(pCur);
+  return SQLITE_OK;
+}
+
+/*
+** Retrieve a column of data.
+*/
+static int schemaPoolColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
+  schemapool_cursor *pCur = (schemapool_cursor*)cur;
+  assert( i==0 || i==1 || i==2 || i==3 );
+  sqlite3_result_int64(ctx, pCur->aData[pCur->iRow*SCHEMAPOOL_NFIELD + i]);
+  return SQLITE_OK;
+}
+
+/*
+** Retrieve the current rowid.
+*/
+static int schemaPoolRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+  schemapool_cursor *pCur = (schemapool_cursor*)cur;
+  *pRowid = pCur->iRow + 1;
+  return SQLITE_OK;
+}
+
+static int schemaPoolEof(sqlite3_vtab_cursor *cur){
+  schemapool_cursor *pCur = (schemapool_cursor*)cur;
+  return pCur->iRow>=pCur->nRow;
+}
+
+/*
+** Advance the cursor to the next row.
+*/
+static int schemaPoolNext(sqlite3_vtab_cursor *cur){
+  schemapool_cursor *pCur = (schemapool_cursor*)cur;
+  pCur->iRow++;
+  return SQLITE_OK;
+}
+
+struct SchemaPool {
+  int nRef;                       /* Number of pointers to this object */
+  int nDelete;                    /* Schema objects deleted by ReleaseAll() */
+  u64 cksum;                      /* Checksum for this Schema contents */
+  Schema *pSchema;                /* Linked list of Schema objects */
+  Schema sSchema;                 /* The single dummy schema object */
+  SchemaPool *pNext;              /* Next element in schemaPoolList */
+};
+extern SchemaPool *sqlite3SchemaPoolList(void);
+
+/*
+** Reset a schemaPool table cursor.
+*/
+static int schemaPoolFilter(
+  sqlite3_vtab_cursor *pVtabCursor, 
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  SchemaPool *pSPool;
+  schemapool_cursor *pCur = (schemapool_cursor*)pVtabCursor;
+
+  sqlite3_free(pCur->aData);
+  pCur->aData = 0;
+  pCur->nRow = 0;
+  pCur->iRow = 0;
+
+  for(pSPool = sqlite3SchemaPoolList(); pSPool; pSPool=pSPool->pNext){
+    pCur->nRow++;
+  }
+
+  if( pCur->nRow ){
+    int iRow = 0;
+    int nByte = SCHEMAPOOL_NFIELD * pCur->nRow * sizeof(i64);
+    pCur->aData = (i64*)sqlite3_malloc(nByte);
+    if( pCur->aData==0 ) return SQLITE_NOMEM;
+    for(pSPool = sqlite3SchemaPoolList(); pSPool; pSPool=pSPool->pNext){
+      Schema *p;
+      i64 nSchema = 0;
+      for(p=pSPool->pSchema; p; p=p->pNext){
+        nSchema++;
+      }
+      pCur->aData[0 + iRow*SCHEMAPOOL_NFIELD] = pSPool->cksum;
+      pCur->aData[1 + iRow*SCHEMAPOOL_NFIELD] = (i64)pSPool->nRef;
+      pCur->aData[2 + iRow*SCHEMAPOOL_NFIELD] = nSchema;
+      pCur->aData[3 + iRow*SCHEMAPOOL_NFIELD] = (i64)pSPool->nDelete;
+      iRow++;
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Analyse the WHERE condition.
+*/
+static int schemaPoolBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  return SQLITE_OK;
+}
+
+/*
+** A virtual table module that merely echos method calls into TCL
+** variables.
+*/
+static sqlite3_module schemaPoolModule = {
+  0,                           /* iVersion */
+  schemaPoolCreate,
+  schemaPoolCreate,
+  schemaPoolBestIndex,
+  schemaPoolDestroy,
+  schemaPoolDestroy,
+  schemaPoolOpen,              /* xOpen - open a cursor */
+  schemaPoolClose,             /* xClose - close a cursor */
+  schemaPoolFilter,            /* xFilter - configure scan constraints */
+  schemaPoolNext,              /* xNext - advance a cursor */
+  schemaPoolEof,               /* xEof */
+  schemaPoolColumn,            /* xColumn - read data */
+  schemaPoolRowid,             /* xRowid - read data */
+  0,                           /* xUpdate */
+  0,                           /* xBegin */
+  0,                           /* xSync */
+  0,                           /* xCommit */
+  0,                           /* xRollback */
+  0,                           /* xFindMethod */
+  0,                           /* xRename */
+};
+
+/*
+** Decode a pointer to an sqlite3 object.
+*/
+extern int getDbPointer(Tcl_Interp *interp, const char *zA, sqlite3 **ppDb);
+
+/*
+** Register the schema virtual table module.
+*/
+static int SQLITE_TCLAPI register_schemapool_module(
+  ClientData clientData, /* Not used */
+  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
+  int objc,              /* Number of arguments */
+  Tcl_Obj *CONST objv[]  /* Command arguments */
+){
+  sqlite3 *db;
+  if( objc!=2 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "DB");
+    return TCL_ERROR;
+  }
+  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3_create_module(db, "schemapool", &schemaPoolModule, 0);
+#endif
+  return TCL_OK;
+}
+
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_TEST) */
+
+/*
+** Register commands with the TCL interpreter.
+*/
+int Sqlitetestschemapool_Init(Tcl_Interp *interp){
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  static struct {
+     char *zName;
+     Tcl_ObjCmdProc *xProc;
+     void *clientData;
+  } aObjCmd[] = {
+     { "register_schemapool_module", register_schemapool_module, 0 },
+  };
+  int i;
+  for(i=0; i<sizeof(aObjCmd)/sizeof(aObjCmd[0]); i++){
+    Tcl_CreateObjCommand(interp, aObjCmd[i].zName, 
+        aObjCmd[i].xProc, aObjCmd[i].clientData, 0);
+  }
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+  return TCL_OK;
+}
+
@@ -77,6 +77,7 @@ const char *sqlite3TestInit(Tcl_Interp *interp){
  extern int Sqlitetest_malloc_Init(Tcl_Interp*);
  extern int Sqlitetest_mutex_Init(Tcl_Interp*);
  extern int Sqlitetestschema_Init(Tcl_Interp*);
+  extern int Sqlitetestschemapool_Init(Tcl_Interp*);
  extern int Sqlitetestsse_Init(Tcl_Interp*);
  extern int Sqlitetesttclvar_Init(Tcl_Interp*);
  extern int Sqlitetestfs_Init(Tcl_Interp*);
@@ -148,6 +149,7 @@ const char *sqlite3TestInit(Tcl_Interp *interp){
  Sqlitetest_malloc_Init(interp);
  Sqlitetest_mutex_Init(interp);
  Sqlitetestschema_Init(interp);
+  Sqlitetestschemapool_Init(interp);
  Sqlitetesttclvar_Init(interp);
  Sqlitetestfs_Init(interp);
  SqlitetestThread_Init(interp);
@@ -614,6 +614,7 @@ int sqlite3RunParser(Parse *pParse, const char *zSql){
    mxSqlLen -= n;
    if( mxSqlLen<0 ){
      pParse->rc = SQLITE_TOOBIG;
+      pParse->nErr++;
      break;
    }
 #ifndef SQLITE_OMIT_WINDOWFUNC
@@ -100,8 +100,8 @@ void sqlite3TreeViewColumnList(
  sqlite3TreeViewLine(pView, "COLUMNS");
  for(i=0; i<nCol; i++){
    u16 flg = aCol[i].colFlags;
-    int moreToFollow = i<(nCol - 1);
-    sqlite3TreeViewPush(&pView, moreToFollow);
+    int colMoreToFollow = i<(nCol - 1);
+    sqlite3TreeViewPush(&pView, colMoreToFollow);
    sqlite3TreeViewLine(pView, 0);
    printf(" %s", aCol[i].zCnName);
    switch( aCol[i].eCType ){
@@ -232,7 +232,7 @@ void sqlite3TreeViewSrcList(TreeView *pView, const SrcList *pSrc){
        Table *pTab = pItem->pTab;
        sqlite3TreeViewColumnList(pView, pTab->aCol, pTab->nCol, 1);
      }
-      assert( pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
+      assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
      sqlite3TreeViewSelect(pView, pItem->pSelect, (--n)>0);
    }
    if( pItem->fg.isTabFunc ){
@@ -999,6 +999,7 @@ void sqlite3TreeViewUpsert(
  sqlite3TreeViewPop(&pView);
 }

+#if TREETRACE_ENABLED
 /*
 ** Generate a human-readable diagram of the data structure that go
 ** into generating an DELETE statement.
@@ -1052,7 +1053,9 @@ void sqlite3TreeViewDelete(
  }
  sqlite3TreeViewPop(&pView);
 }
+#endif /* TREETRACE_ENABLED */

+#if TREETRACE_ENABLED
 /*
 ** Generate a human-readable diagram of the data structure that go
 ** into generating an INSERT statement.
@@ -1120,7 +1123,9 @@ void sqlite3TreeViewInsert(
  }
  sqlite3TreeViewPop(&pView);
 }
+#endif /* TREETRACE_ENABLED */

+#if TREETRACE_ENABLED
 /*
 ** Generate a human-readable diagram of the data structure that go
 ** into generating an UPDATE statement.
@@ -1196,6 +1201,7 @@ void sqlite3TreeViewUpdate(
  }
  sqlite3TreeViewPop(&pView);
 }
+#endif /* TREETRACE_ENABLED */

 #ifndef SQLITE_OMIT_TRIGGER
 /*
@@ -52,13 +52,34 @@ Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
  Trigger *pList;           /* List of triggers to return */
  HashElem *p;              /* Loop variable for TEMP triggers */

+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  char *zSchema = 0;
+  sqlite3 *db = pParse->db;
+  if( IsSharedSchema(db) ){
+    zSchema = db->aDb[sqlite3SchemaToIndex(db, pTab->pSchema)].zDbSName;
+  }
+#endif
+
  assert( pParse->disableTriggers==0 );
  pTmpSchema = pParse->db->aDb[1].pSchema;
  p = sqliteHashFirst(&pTmpSchema->trigHash);
  pList = pTab->pTrigger;
  while( p ){
    Trigger *pTrig = (Trigger *)sqliteHashData(p);
-    if( pTrig->pTabSchema==pTab->pSchema
+
+    int bSchemaMatch;
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+    if( zSchema ){
+      /* Shared-schema */
+      bSchemaMatch = (0==sqlite3StrICmp(pTrig->zTabSchema, zSchema));
+    }else
+#endif
+    {
+      /* Non-shared-schema */
+      bSchemaMatch = (pTrig->pTabSchema==pTab->pSchema);
+    }
+
+    if( bSchemaMatch
     && pTrig->table
     && 0==sqlite3StrICmp(pTrig->table, pTab->zName)
     && pTrig->pTabSchema!=pTmpSchema
@@ -68,7 +89,7 @@ Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
    }else if( pTrig->op==TK_RETURNING ){
 #ifndef SQLITE_OMIT_VIRTUALTABLE
      assert( pParse->db->pVtabCtx==0 );
-#endif
+#endif 
      assert( pParse->bReturning );
      assert( &(pParse->u1.pReturning->retTrig) == pTrig );
      pTrig->table = pTab->zName;
@@ -258,6 +279,12 @@ void sqlite3BeginTrigger(
  pTrigger->zName = zName;
  zName = 0;
  pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  if( IsSharedSchema(db) && iDb==1 ){
+    int iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    pTrigger->zTabSchema = sqlite3DbStrDup(db, db->aDb[iTabDb].zDbSName);
+  }
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
  pTrigger->pSchema = db->aDb[iDb].pSchema;
  pTrigger->pTabSchema = pTab->pSchema;
  pTrigger->op = (u8)op;
@@ -351,6 +378,23 @@ void sqlite3FinishTrigger(
    Vdbe *v;
    char *z;

+    /* If this is a new CREATE TABLE statement, and if shadow tables
+    ** are read-only, and the trigger makes a change to a shadow table,
+    ** then raise an error - do not allow the trigger to be created. */
+    if( sqlite3ReadOnlyShadowTables(db) ){
+      TriggerStep *pStep;
+      for(pStep=pTrig->step_list; pStep; pStep=pStep->pNext){
+        if( pStep->zTarget!=0
+         && sqlite3ShadowTableName(db, pStep->zTarget)
+        ){
+          sqlite3ErrorMsg(pParse, 
+            "trigger \"%s\" may not write to shadow table \"%s\"",
+            pTrig->zName, pStep->zTarget);
+          goto triggerfinish_cleanup;
+        }
+      }
+    }
+
    /* Make an entry in the sqlite_schema table */
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) goto triggerfinish_cleanup;
@@ -364,7 +408,7 @@ void sqlite3FinishTrigger(
       pTrig->table, z);
    sqlite3DbFree(db, z);
    sqlite3ChangeCookie(pParse, iDb);
-    sqlite3VdbeAddParseSchemaOp(v, iDb,
+    sqlite3VdbeAddParseSchemaOp(pParse, iDb,
        sqlite3MPrintf(db, "type='trigger' AND name='%q'", zName), 0);
  }

@@ -583,6 +627,9 @@ void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){
  sqlite3DeleteTriggerStep(db, pTrigger->step_list);
  sqlite3DbFree(db, pTrigger->zName);
  sqlite3DbFree(db, pTrigger->table);
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  sqlite3DbFree(db, pTrigger->zTabSchema);
+#endif
  sqlite3ExprDelete(db, pTrigger->pWhen);
  sqlite3IdListDelete(db, pTrigger->pColumns);
  sqlite3DbFree(db, pTrigger);
@@ -654,6 +701,7 @@ void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){

  iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
  assert( iDb>=0 && iDb<db->nDb );
+  sqlite3SchemaWritable(pParse, iDb);
  pTable = tableOfTrigger(pTrigger);
  assert( (pTable && pTable->pSchema==pTrigger->pSchema) || iDb==1 );
 #ifndef SQLITE_OMIT_AUTHORIZATION
@@ -1146,7 +1194,9 @@ static TriggerPrg *codeRowTrigger(
  int iEndTrigger = 0;        /* Label to jump to if WHEN is false */
  Parse sSubParse;            /* Parse context for sub-vdbe */

-  assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
+  assert( pTrigger->zName==0 || IsSharedSchema(pParse->db)
+      || pTab==tableOfTrigger(pTrigger)
+  );
  assert( pTop->pVdbe );

  /* Allocate the TriggerPrg and SubProgram objects. To ensure that they
@@ -1253,7 +1303,9 @@ static TriggerPrg *getRowTrigger(
  Parse *pRoot = sqlite3ParseToplevel(pParse);
  TriggerPrg *pPrg;

-  assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
+  assert( pTrigger->zName==0 || IsSharedSchema(pParse->db)
+      || pTab==tableOfTrigger(pTrigger) 
+  );

  /* It may be that this trigger has already been coded (or is in the
  ** process of being coded). If this is the case, then an entry with
@@ -190,7 +190,7 @@ void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
  va_list ap;
  sqlite3 *db = pParse->db;
  assert( db!=0 );
-  assert( db->pParse==pParse );
+  assert( db->pParse==pParse || db->pParse->pToplevel==pParse );
  db->errByteOffset = -2;
  va_start(ap, zFormat);
  zMsg = sqlite3VMPrintf(db, zFormat, ap);
@@ -125,6 +125,7 @@ void sqlite3Vacuum(Parse *pParse, Token *pNm, Expr *pInto){
  }
  if( iDb!=1 ){
    int iIntoReg = 0;
+    sqlite3SchemaWritable(pParse, iDb);
    if( pInto && sqlite3ResolveSelfReference(pParse,0,0,pInto,0)==0 ){
      iIntoReg = ++pParse->nMem;
      sqlite3ExprCode(pParse, pInto, iIntoReg);
@@ -3863,13 +3863,6 @@ case OP_Transaction: {
   && pOp->p5
   && (iMeta!=pOp->p3 || pDb->pSchema->iGeneration!=pOp->p4.i)
  ){
-    /*
-    ** IMPLEMENTATION-OF: R-03189-51135 As each SQL statement runs, the schema
-    ** version is checked to ensure that the schema has not changed since the
-    ** SQL statement was prepared.
-    */
-    sqlite3DbFree(db, p->zErrMsg);
-    p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
    /* If the schema-cookie from the database file matches the cookie 
    ** stored with the in-memory representation of the schema, do
    ** not reload the schema from the database file.
@@ -3886,6 +3879,13 @@ case OP_Transaction: {
    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
      sqlite3ResetOneSchema(db, pOp->p1);
    }
+    /*
+    ** IMPLEMENTATION-OF: R-03189-51135 As each SQL statement runs, the schema
+    ** version is checked to ensure that the schema has not changed since the
+    ** SQL statement was prepared.
+    */
+    sqlite3DbFree(db, p->zErrMsg);
+    p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
    p->expired = 1;
    rc = SQLITE_SCHEMA;

@@ -222,7 +222,7 @@ VdbeOp *sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp,int iLineno);
 #else
 # define sqlite3ExplainBreakpoint(A,B) /*no-op*/
 #endif
-void sqlite3VdbeAddParseSchemaOp(Vdbe*, int, char*, u16);
+void sqlite3VdbeAddParseSchemaOp(Parse*,int,char*,u16);
 void sqlite3VdbeChangeOpcode(Vdbe*, int addr, u8);
 void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
 void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
@@ -381,6 +381,7 @@ int sqlite3VdbeAddFunctionCall(
  addr = sqlite3VdbeAddOp4(v, eCallCtx ? OP_PureFunc : OP_Function,
                           p1, p2, p3, (char*)pCtx, P4_FUNCCTX);
  sqlite3VdbeChangeP5(v, eCallCtx & NC_SelfRef);
+  sqlite3MayAbort(pParse);
  return addr;
 }

@@ -473,8 +474,10 @@ void sqlite3VdbeExplainPop(Parse *pParse){
 ** The zWhere string must have been obtained from sqlite3_malloc().
 ** This routine will take ownership of the allocated memory.
 */
-void sqlite3VdbeAddParseSchemaOp(Vdbe *p, int iDb, char *zWhere, u16 p5){
+void sqlite3VdbeAddParseSchemaOp(Parse *pParse, int iDb, char *zWhere, u16 p5){
+  Vdbe *p = pParse->pVdbe;
  int j;
+  sqlite3SchemaWritable(pParse, iDb);
  sqlite3VdbeAddOp4(p, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
  sqlite3VdbeChangeP5(p, p5);
  for(j=0; j<p->db->nDb; j++) sqlite3VdbeUsesBtree(p, j);
@@ -716,6 +719,7 @@ int sqlite3VdbeAssertMayAbort(Vdbe *v, int mayAbort){
     || opcode==OP_VDestroy
     || opcode==OP_VCreate
     || opcode==OP_ParseSchema
+     || opcode==OP_Function || opcode==OP_PureFunc
     || ((opcode==OP_Halt || opcode==OP_HaltIfNull) 
      && ((pOp->p1)!=SQLITE_OK && pOp->p2==OE_Abort))
    ){
@@ -135,6 +135,7 @@ int sqlite3_blob_open(
  Table *pTab;
  Incrblob *pBlob = 0;
  Parse sParse;
+  int bUnlock;            /* True to unlock reusable schemas before returning */

 #ifdef SQLITE_ENABLE_API_ARMOR
  if( ppBlob==0 ){
@@ -151,6 +152,7 @@ int sqlite3_blob_open(

  sqlite3_mutex_enter(db->mutex);

+  bUnlock = sqlite3LockReusableSchema(db);
  pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
  while(1){
    sqlite3ParseObjectInit(&sParse,db);
@@ -336,6 +338,7 @@ int sqlite3_blob_open(
  }

 blob_open_out:
+  sqlite3UnlockReusableSchema(db, bUnlock);
  if( rc==SQLITE_OK && db->mallocFailed==0 ){
    *ppBlob = (sqlite3_blob *)pBlob;
  }else{
@@ -192,6 +192,24 @@ void sqlite3VtabLock(VTable *pVTab){
 VTable *sqlite3GetVTable(sqlite3 *db, Table *pTab){
  VTable *pVtab;
  assert( IsVirtual(pTab) );
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  if( IsSharedSchema(db) ){
+    int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    if( iDb!=1 ){
+      VTable **pp;
+      for(pp=&db->aDb[iDb].pVTable; *pp; pp=&(*pp)->pNext){
+        if( sqlite3StrICmp(pTab->zName, (*pp)->zName)==0 ) break;
+      }
+      pVtab = *pp;
+      if( pVtab && pTab->nCol<=0 ){
+        *pp = pVtab->pNext;
+        sqlite3VtabUnlock(pVtab);
+        pVtab = 0;
+      }
+      return pVtab;
+    }
+  }
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
  for(pVtab=pTab->u.vtab.p; pVtab && pVtab->db!=db; pVtab=pVtab->pNext);
  return pVtab;
 }
@@ -499,7 +517,7 @@ void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){

    sqlite3VdbeAddOp0(v, OP_Expire);
    zWhere = sqlite3MPrintf(db, "name=%Q AND sql=%Q", pTab->zName, zStmt);
-    sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere, 0);
+    sqlite3VdbeAddParseSchemaOp(pParse, iDb, zWhere, 0);
    sqlite3DbFree(db, zStmt);

    iReg = ++pParse->nMem;
@@ -569,6 +587,7 @@ static int vtabCallConstructor(
  char *zModuleName;
  int iDb;
  VtabCtx *pCtx;
+  int nByte;                      /* Bytes of space to allocate */

  assert( IsVirtual(pTab) );
  azArg = (const char *const*)pTab->u.vtab.azArg;
@@ -588,7 +607,11 @@ static int vtabCallConstructor(
    return SQLITE_NOMEM_BKPT;
  }

-  pVTable = sqlite3MallocZero(sizeof(VTable));
+  nByte = sizeof(VTable);
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  nByte += sqlite3Strlen30(pTab->zName) + 1;
+#endif
+  pVTable = (VTable*)sqlite3MallocZero(nByte);
  if( !pVTable ){
    sqlite3OomFault(db);
    sqlite3DbFree(db, zModuleName);
@@ -596,6 +619,10 @@ static int vtabCallConstructor(
  }
  pVTable->db = db;
  pVTable->pMod = pMod;
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+  pVTable->zName = (char*)&pVTable[1];
+  memcpy(pVTable->zName, pTab->zName, nByte-sizeof(VTable));
+#endif
  pVTable->eVtabRisk = SQLITE_VTABRISK_Normal;

  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
@@ -638,12 +665,23 @@ static int vtabCallConstructor(
      int iCol;
      u16 oooHidden = 0;
      /* If everything went according to plan, link the new VTable structure
-      ** into the linked list headed by pTab->u.vtab.p. Then loop through the 
-      ** columns of the table to see if any of them contain the token "hidden".
-      ** If so, set the Column COLFLAG_HIDDEN flag and remove the token from
-      ** the type string.  */
-      pVTable->pNext = pTab->u.vtab.p;
-      pTab->u.vtab.p = pVTable;
+      ** into the linked list headed by pTab->u.vtab.p. Or, if this is a
+      ** reusable schema, into the linked list headed by Db.pVTable.
+      **
+      ** Then loop through the columns of the table to see if any of them
+      ** contain the token "hidden". If so, set the Column COLFLAG_HIDDEN flag
+      ** and remove the token from the type string.  */
+#ifdef SQLITE_ENABLE_SHARED_SCHEMA
+      if( IsSharedSchema(db) && iDb!=1 ){
+        pVTable->pNext = db->aDb[iDb].pVTable;
+        db->aDb[iDb].pVTable = pVTable;
+      }else
+#endif /* ifdef SQLITE_ENABLE_SHARED_SCHEMA */
+      {
+        assert( IsVirtual(pTab) );
+        pVTable->pNext = pTab->u.vtab.p;
+        pTab->u.vtab.p = pVTable;
+      }

      for(iCol=0; iCol<pTab->nCol; iCol++){
        char *zType = sqlite3ColumnType(&pTab->aCol[iCol], "");
@@ -698,6 +736,7 @@ int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
  assert( pTab );
  assert( IsVirtual(pTab) );
  if( sqlite3GetVTable(db, pTab) ){
+    assert( !IsVirtual(pTab) || pTab->nCol>0 );
    return SQLITE_OK;
  }

@@ -1433,7 +1433,7 @@ static int whereKeyStats(
 #endif
  assert( pRec!=0 );
  assert( pIdx->nSample>0 );
-  assert( pRec->nField>0 && pRec->nField<=pIdx->nSampleCol );
+  assert( pRec->nField>0 );

  /* Do a binary search to find the first sample greater than or equal
  ** to pRec. If pRec contains a single field, the set of samples to search
@@ -1479,7 +1479,7 @@ static int whereKeyStats(
  ** it is extended to two fields. The duplicates that this creates do not 
  ** cause any problems.
  */
-  nField = pRec->nField;
+  nField = MIN(pRec->nField, pIdx->nSample);
  iCol = 0;
  iSample = pIdx->nSample * nField;
  do{
@@ -4168,6 +4168,7 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
  sqlite3 *db = pWInfo->pParse->db;
  int rc = SQLITE_OK;
  int bFirstPastRJ = 0;
+  int hasRightJoin = 0;
  WhereLoop *pNew;


@@ -4188,15 +4189,16 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
      ** prevents the right operand of a RIGHT JOIN from being swapped with
      ** other elements even further to the right.
      **
-      ** The JT_LTORJ term prevents any FROM-clause term reordering for terms
-      ** to the left of a RIGHT JOIN.  This is conservative.  Relaxing this
-      ** constraint somewhat to prevent terms from crossing from the right
-      ** side of a LEFT JOIN over to the left side when they are on the
-      ** left side of a RIGHT JOIN would be sufficient for all known failure
-      ** cases.  FIX ME: Implement this optimization.
+      ** The JT_LTORJ case and the hasRightJoin flag work together to
+      ** prevent FROM-clause terms from moving from the right side of
+      ** a LEFT JOIN over to the left side of that join if the LEFT JOIN
+      ** is itself on the left side of a RIGHT JOIN.
      */
+      if( pItem->fg.jointype & JT_LTORJ ) hasRightJoin = 1;
      mPrereq |= mPrior;
      bFirstPastRJ = (pItem->fg.jointype & JT_RIGHT)!=0;
+    }else if( !hasRightJoin ){
+      mPrereq = 0;
    }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pItem->pTab) ){
@@ -622,7 +622,8 @@ static int codeEqualityTerm(
        }
        sqlite3ExprDelete(db, pX);
      }else{
-        aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*nEq);
+        int n = sqlite3ExprVectorSize(pX->pLeft);
+        aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*MAX(nEq,n));
        eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap, &iTab);
      }
      pX = pExpr;
@@ -7033,6 +7033,8 @@ set sqlite_fts3_enable_parentheses $saved

 #-------------------------------------------------------------------------
 #
+set saved $sqlite_fts3_enable_parentheses
+set sqlite_fts3_enable_parentheses 1
 reset_db
 do_test 52.0 {
  sqlite3 db {}
@@ -7228,5 +7230,438 @@ do_catchsql_test 52.1 {
  SELECT * FROM t1, t2;
 } {1 {database disk image is malformed}}

+#-------------------------------------------------------------------------
+#
+reset_db
+do_test 53.0 {
+  sqlite3 db {}
+  db deserialize [decode_hexdb {
+.open --hexdb
+| size 8192 pagesize 1024 filename crash-7bc.txt.db
+| page 1 offset 0
+|      0: 53 51 4c 69 74 65 20 66 6f 72 6d 61 74 20 33 00   SQLite format 3.
+|     16: 04 00 01 01 00 40 20 20 00 00 00 00 00 00 00 08   .....@  ........
+|     32: 00 00 00 00 00 00 00 00 00 00 00 06 00 00 00 04   ................
+|     48: 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00   ................
+|     96: 00 00 00 00 0d 02 f3 00 07 01 51 00 03 c8 03 63   ..........Q....c
+|    112: 02 fb 02 0a 02 c0 01 a8 01 51 00 00 00 00 00 00   .........Q......
+|    336: 00 55 07 07 17 1b 1b 01 81 01 74 61 62 6c 65 74   .U........tablet
+|    352: 31 5f 73 74 61 74 74 31 5f 73 74 61 74 07 43 52   1_statt1_stat.CR
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+|    448: 74 31 5f 64 6f 63 73 69 7a 65 06 43 52 45 41 54   t1_docsize.CREAT
+|    464: 45 20 54 41 42 4c 45 20 27 74 31 5f 64 6f 63 73   E TABLE 't1_docs
+|    480: 69 7a 65 27 28 64 6f 63 69 64 20 49 4e 54 45 47   ize'(docid INTEG
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+|    544: 69 72 74 31 5f 73 65 67 64 69 72 04 43 52 45 41   irt1_segdir.CREA
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+|    816: 5f 73 65 67 6d 65 6e 74 73 27 28 62 6c 6f 63 6b   _segments'(block
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+|    880: 65 74 31 5f 63 6f 6e 74 65 6e 74 74 31 5f 63 6f   et1_contentt1_co
+|    896: 6e 74 65 6e 74 02 43 52 45 41 54 45 20 54 41 42   ntent.CREATE TAB
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+|    960: 2c 20 27 63 31 62 27 29 36 01 06 17 11 11 08 5b   , 'c1b')6......[
+|    976: 74 61 62 6c 65 74 31 74 31 43 52 45 41 54 45 20   tablet1t1CREATE 
+|    992: 56 49 52 54 55 41 4c 20 54 41 42 4c 45 20 74 31   VIRTUAL TABLE t1
+|   1008: 20 55 53 49 4e 47 20 66 74 73 34 28 30 2c 62 29    USING fts4(0,b)
+| page 2 offset 1024
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+|    864: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    880: 30 30 30 30 30 30 30 30 30 05 01 00 00 00 00 00   000000000.......
+| end crash-7bc.txt.db
+}]} {}
+
+do_execsql_test 53.1 {
+  SELECT*FROM t1 WHERE t1 MATCH'ATE"0"OR"2D:P"""ATE"0"OR"2:P"""';
+} {0 {ATE 2:P}}
+set sqlite_fts3_enable_parentheses $saved
+
+#-------------------------------------------------------------------------
+#
+reset_db
+do_test 54.0 {
+  sqlite3 db {}
+  db deserialize [decode_hexdb {
+.open --hexdb
+| size 8192 pagesize 1024 filename crash-365.txt.db
+| page 1 offset 0
+|      0: 53 51 4c 69 74 65 20 66 6f 72 6d 61 74 20 33 00   SQLite format 3.
+|     16: 04 00 01 01 00 40 20 20 00 00 00 00 00 00 00 08   .....@  ........
+|     32: 00 00 00 00 00 00 00 00 00 00 00 06 00 00 00 04   ................
+|     96: 00 00 00 00 0d 02 f3 00 07 01 51 00 03 c8 03 63   ..........Q....c
+|    112: 02 fb 02 0a 02 c0 01 a8 01 51 00 00 00 00 00 00   .........Q......
+|    336: 00 55 07 07 17 1b 1b 01 81 01 74 61 62 6c 65 74   .U........tablet
+|    352: 31 5f 73 74 61 74 74 31 5f 73 74 61 74 07 43 52   1_statt1_stat.CR
+|    368: 45 41 54 45 20 54 41 42 4c 45 20 27 74 31 5f 73   EATE TABLE 't1_s
+|    384: 74 61 74 27 28 69 64 20 49 4e 54 45 47 45 52 20   tat'(id INTEGER 
+|    400: 50 52 49 4d 41 52 59 20 4b 45 59 2c 20 76 61 6c   PRIMARY KEY, val
+|    416: 75 65 20 42 4c 4f 42 29 60 06 07 17 21 21 01 81   ue BLOB)`...!!..
+|    432: 0b 74 61 62 6c 65 74 31 5f 64 6f 63 73 69 7a 65   .tablet1_docsize
+|    448: 74 31 5f 64 6f 63 73 69 7a 65 06 43 52 45 41 54   t1_docsize.CREAT
+|    464: 45 20 54 41 42 4c 45 20 27 74 31 5f 64 6f 63 73   E TABLE 't1_docs
+|    480: 69 7a 65 27 28 64 6f 63 69 64 20 49 4e 54 45 47   ize'(docid INTEG
+|    496: 45 52 20 50 52 49 4d 41 52 59 20 4b 45 59 2c 20   ER PRIMARY KEY, 
+|    512: 73 69 7a 65 20 42 4c 4f 42 29 81 33 04 07 17 1f   size BLOB).3....
+|    528: 1f 01 82 35 74 61 62 6c 65 74 31 5f 73 65 67 64   ...5tablet1_segd
+|    544: 69 72 74 31 5f 73 65 67 64 69 72 04 43 52 45 41   irt1_segdir.CREA
+|    560: 54 45 20 54 41 42 4c 45 20 27 74 31 5f 73 65 67   TE TABLE 't1_seg
+|    576: 64 69 72 27 28 6c 65 76 65 6c 20 49 4e 54 45 47   dir'(level INTEG
+|    592: 45 52 2c 69 64 78 20 49 4e 54 45 47 45 52 2c 73   ER,idx INTEGER,s
+|    608: 74 61 72 74 5f 62 6c 6f 63 6b 20 49 4e 54 45 47   tart_block INTEG
+|    624: 45 52 2c 6c 65 61 76 65 73 5f 65 6e 64 5f 62 6c   ER,leaves_end_bl
+|    640: 6f 63 6b 20 49 4e 54 45 47 45 52 2c 65 6e 64 5f   ock INTEGER,end_
+|    656: 62 6c 6f 63 6b 20 49 4e 54 45 47 45 52 2c 72 6f   block INTEGER,ro
+|    672: 6f 74 20 42 4c 4f 42 2c 50 52 49 4d 41 52 59 20   ot BLOB,PRIMARY 
+|    688: 4b 45 59 28 6c 65 76 65 6c 2c 20 69 64 78 29 29   KEY(level, idx))
+|    704: 31 05 06 17 45 1f 01 00 69 6e 64 65 78 73 71 6c   1...E...indexsql
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+|    784: 65 6e 74 73 74 31 5f 73 65 67 6d 65 6e 74 73 03   entst1_segments.
+|    800: 43 52 45 41 54 45 20 54 41 42 4c 45 20 27 74 31   CREATE TABLE 't1
+|    816: 5f 73 65 67 6d 65 6e 74 73 27 28 62 6c 6f 63 6b   _segments'(block
+|    832: 69 64 20 49 4e 54 45 47 45 52 20 50 52 49 4d 41   id INTEGER PRIMA
+|    848: 52 59 20 4b 45 59 2c 20 62 6c 6f 63 6b 20 42 4c   RY KEY, block BL
+|    864: 4f 42 29 63 02 07 17 21 21 01 81 11 74 61 62 6c   OB)c...!!...tabl
+|    880: 65 74 31 5f 63 6f 6e 74 65 6e 74 74 31 5f 63 6f   et1_contentt1_co
+|    896: 6e 74 65 6e 74 02 43 52 45 41 54 45 20 54 41 42   ntent.CREATE TAB
+|    912: 4c 45 20 27 74 31 5f 63 6f 6e 74 65 6e 74 27 28   LE 't1_content'(
+|    928: 64 6f 63 69 64 20 49 4e 54 45 47 45 52 20 50 52   docid INTEGER PR
+|    944: 49 4d 41 52 59 20 4b 45 59 2c 20 27 63 30 30 27   IMARY KEY, 'c00'
+|    960: 2c 20 27 63 31 62 27 29 36 01 06 17 11 11 08 5b   , 'c1b')6......[
+|    976: 74 61 62 6c 65 74 31 74 31 43 52 45 41 54 45 20   tablet1t1CREATE 
+|    992: 56 49 52 54 55 41 4c 20 54 41 42 4c 45 20 74 31   VIRTUAL TABLE t1
+|   1008: 20 55 53 49 4e 47 20 66 74 73 34 28 30 2c 62 29    USING fts4(0,b)
+| page 2 offset 1024
+|      0: 0d 00 00 00 03 00 0f 00 00 23 00 16 00 0f 00 05   .........#......
+|     16: 03 04 00 08 0f 61 0b 02 04 00 08 1b 41 54 45 20   .....a......ATE 
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+|    848: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    864: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    880: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    896: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    912: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    928: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    944: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    960: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    976: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    992: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|   1008: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+| page 3 offset 2048
+|      0: 0d 00 00 00 02 03 86 00 03 f4 03 86 00 00 00 00   ................
+|    896: 00 00 00 00 00 00 87 62 02 04 00 8f 48 00 d5 07   .......b....H...
+|    912: 66 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   f000000000000000
+|    928: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    944: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    960: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    976: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    992: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|   1008: 00 00 00 08 0a 01 03 00 1a 00 01 30 03 01 02 00   ...........0....
+| page 4 offset 3072
+|      0: 0d 00 00 00 03 03 9e 00 03 ed 03 bc 03 9e 00 01   ................
+|    912: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 1c 03   ................
+|    928: 07 08 01 08 08 15 2c 02 30 20 31 36 00 01 30 03   ......,.0 16..0.
+|    944: 03 02 00 00 01 61 05 03 01 01 02 00 2f 02 07 08   .....a....../...
+|    960: 09 08 08 15 54 30 20 33 36 00 01 30 03 02 02 00   ....T0 36..0....
+|    976: 00 01 32 05 02 01 01 03 00 00 03 61 74 65 05 02   ..2........ate..
+|    992: 01 01 02 00 00 01 70 05 02 01 01 04 00 11 01 07   ......p.........
+|   1008: 08 08 09 01 17 14 02 32 20 39 39 37 01 01 01 66   .......2 997...f
+| page 5 offset 4096
+|      0: 0a 00 00 00 03 03 ee 00 03 fb 03 f5 03 ee 00 00   ................
+|    992: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 06 04   ................
+|   1008: 08 01 01 02 03 05 04 08 09 01 02 04 04 08 08 09   ................
+| page 6 offset 5120
+|      0: 0d 00 00 00 03 03 eb 00 03 f9 03 f2 00 00 00 00   ................
+|    992: 00 00 00 00 00 00 00 00 00 00 00 05 03 03 00 10   ................
+|   1008: 01 01 05 02 03 00 10 01 03 05 01 03 00 10 01 01   ................
+| page 7 offset 6144
+|      0: 0d 00 00 00 01 03 f6 00 03 f6 00 00 00 00 00 00   ................
+|   1008: 00 00 00 00 00 00 08 00 03 00 16 03 03 05 e0 07   ................
+| page 8 offset 7168
+|      0: 00 00 00 00 30 30 30 30 30 30 30 30 30 30 30 30   ....000000000000
+|     16: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|     32: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|     48: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|     64: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|     80: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|     96: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    112: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    128: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    144: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    160: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    176: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    192: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    208: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    224: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    240: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    256: 30 30 30 30 30 2f 30 30 30 30 30 30 30 30 30 30   00000/0000000000
+|    272: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    288: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    304: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    320: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    336: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    352: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    368: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    384: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    400: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    416: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    432: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    448: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    464: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    480: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    496: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    512: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    528: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    544: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    560: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    576: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    592: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    608: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    624: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    640: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    656: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    672: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    688: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    704: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    720: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    736: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    752: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    768: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    784: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    800: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    816: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    832: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    848: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    864: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30   0000000000000000
+|    880: 30 30 30 30 30 30 30 30 30 05 01 01 01 02 00 00   000000000.......
+| end crash-365.txt.db
+}]} {}
+
+do_execsql_test 54.1 {
+  SELECT rowid, quote(matchinfo(t1,'pcxybspcxybs')) FROM t1 WHERE t1 MATCH'ATE"0"OR"2:P"""';
+}

 finish_test
@@ -18,6 +18,10 @@ set ::testprefix fts3fault
 # If SQLITE_ENABLE_FTS3 is not defined, omit this file.
 ifcapable !fts3 { finish_test ; return }

+set ::TMPDBERROR [list 1 \
+  {unable to open a temporary database file for storing temporary tables}
+]
+
 # Test error handling in the sqlite3Fts3Init() function. This is the 
 # function that registers the FTS3 module and various support functions
 # with SQLite.
@@ -49,7 +53,7 @@ do_faultsim_test 2 -prep {
 } -body {
  execsql { ALTER TABLE t1 RENAME TO t2 }
 } -test {
-  faultsim_test_result {0 {}} 
+  faultsim_test_result {0 {}} $::TMPDBERROR
 }

 # Test error handling in the special case where a single prefix query 
@@ -194,7 +198,7 @@ do_faultsim_test 8.2 -faults oom-t* -prep {
 } -body {
  execsql { SELECT mit(matchinfo(t8, 's')) FROM t8 WHERE t8 MATCH 'a b c' }
 } -test {
-  faultsim_test_result {0 3}
+  faultsim_test_result {0 3} $::TMPDBERROR
 }
 do_faultsim_test 8.3 -prep { 
  faultsim_restore_and_reopen
@@ -215,12 +215,15 @@ do_faultsim_test 8.1 -faults oom* -prep {
  faultsim_test_result {0 {}}
 }

+set ::TMPDBERROR [list 1 \
+  {unable to open a temporary database file for storing temporary tables}
+]
 do_faultsim_test 8.2 -faults oom* -prep {
  faultsim_restore_and_reopen
 } -body {
  execsql { ALTER TABLE t8 RENAME TO t8ii }
 } -test {
-  faultsim_test_result {0 {}}
+  faultsim_test_result {0 {}} $::TMPDBERROR
 }

 #-------------------------------------------------------------------------
@@ -786,4 +786,19 @@ do_execsql_test join8-25020 {
  SELECT 1 FROM t1 LEFT JOIN t2 ON true JOIN t3 ON (b2 IN (a1)) FULL JOIN t4 ON true;
 } {1}

+# 2022-07-13
+# forum/forumpost/174afeae57
+#
+reset_db
+db null -
+do_execsql_test join8-26000 {
+  CREATE TABLE t1(a INT);
+  CREATE TABLE t2(b INT, c INT);
+  CREATE VIEW t3(d) AS SELECT NULL FROM t2 FULL OUTER JOIN t1 ON c=a UNION ALL SELECT b FROM t2;
+  INSERT INTO t1(a) VALUES (NULL);
+  INSERT INTO t2(b, c) VALUES (99, NULL);
+  SELECT DISTINCT b, c, d FROM t2, t3 WHERE b<>0
+   UNION SELECT DISTINCT b, c, d FROM t2, t3 WHERE b ISNULL;
+} {99 - - 99 - 99}
+
 finish_test
@@ -867,4 +867,22 @@ do_catchsql_test json-18.5 {
  SELECT json_extract('{"":8}', '$.');
 } {1 {JSON path error near ''}}

+# 2022-08-29 https://sqlite.org/forum/forumpost/9b9e4716c0d7bbd1
+# This is not a problem specifically with JSON functions.  It is
+# a problem with transaction control.  But the json() function makes
+# the problem more easily accessible, so it is tested here.
+#
+do_execsql_test json-19.1 {
+  DROP TABLE IF EXISTS t1;
+  CREATE TABLE t1(x);
+} {}
+do_catchsql_test json-19.2 {
+  BEGIN;
+  INSERT INTO t1 VALUES(0), (json('not-valid-json'));
+} {1 {malformed JSON}}
+do_execsql_test json-19.3 {
+  COMMIT;
+  SELECT * FROM t1;
+} {}
+
 finish_test
@@ -664,6 +664,7 @@ proc do_write_test {name tbl sql} {

  if {$::DO_MALLOC_TEST } {
    set answers [list {1 {out of memory}} {0 {}}]
+    lappend answers [list 1 {unable to open a temporary database file for storing temporary tables}]
    if {$::DO_MALLOC_TEST==1} {
      set modes {100000 persistent}
    } else {
@@ -141,3 +141,5 @@ do_eqp_test 111 {
     `--RIGHT
        `--SCAN generate_series VIRTUAL TABLE INDEX 23:
 }
+
+finish_test
@@ -156,6 +156,47 @@ do_execsql_test offset1-1.4.9 {
  LIMIT 9 OFFSET 1;
 } {2 b 3 c 4 d 5 e 6 w 7 x 8 y 9 z}

-
+# 2022-08-04
+# https://sqlite.org/forum/forumpost/6b5e9188f0657616
+#
+do_execsql_test offset1-2.0 {
+  CREATE TABLE employees (
+    id integer primary key,
+    name text,
+    city text,
+    department text,
+    salary integer
+  );
+  INSERT INTO employees VALUES
+    (11,'Diane','London','hr',70),
+    (12,'Bob','London','hr',78),
+    (21,'Emma','London','it',84),
+    (22,'Grace','Berlin','it',90),
+    (23,'Henry','London','it',104),
+    (24,'Irene','Berlin','it',104),
+    (25,'Frank','Berlin','it',120),
+    (31,'Cindy','Berlin','sales',96),
+    (32,'Dave','London','sales',96),
+    (33,'Alice','Berlin','sales',100);
+  CREATE VIEW v AS
+    SELECT * FROM (
+      SELECT * FROM employees 
+       WHERE salary < 100
+       ORDER BY salary desc)
+     UNION ALL 
+     SELECT * FROM (
+       SELECT * FROM employees
+       WHERE salary >= 100
+       ORDER BY salary asc);
+} {}
+do_execsql_test offset1-2.1 {
+  SELECT * FROM v LIMIT 5 OFFSET 2;
+} {
+  22  Grace  Berlin  it      90
+  21  Emma   London  it      84
+  12  Bob    London  hr      78
+  11  Diane  London  hr      70
+  33  Alice  Berlin  sales   100
+}

 finish_test
@@ -239,4 +239,26 @@ do_execsql_test regexp1-2.22 {
  SELECT 'abc$¢€xyz' REGEXP '^abc[^\u0025-X][^ -\u007f][^\u20ab]xyz$'
 } {1}

+# 2022-07-03
+# https://sqlite.org/forum/forumpost/96692f8ba5
+# The REGEXP extension mishandles the prefix search optimization when
+# the prefix contains 3-byte UTF8 characters.
+#
+reset_db
+load_static_extension db regexp
+do_execsql_test regexp1-3.1 {
+  CREATE TABLE t1(id INTEGER PRIMARY KEY, a TEXT);
+  INSERT INTO t1(id, a) VALUES(1, '日本語');
+  SELECT a, hex(a), length(a) FROM t1;
+} {日本語 E697A5E69CACE8AA9E 3}
+do_execsql_test regexp1-3.2 {
+  SELECT * FROM t1 WHERE a='日本語';
+} {1 日本語}
+do_execsql_test regexp1-3.3 {
+  SELECT * FROM t1 WHERE a LIKE '日本語';
+} {1 日本語}
+do_execsql_test regexp1-3.4 {
+  SELECT * FROM t1 wHERE a REGEXP '日本語';
+} {1 日本語}
+
 finish_test
@@ -0,0 +1,394 @@
+# 2017 August 9
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix reuse1
+
+ifcapable !sharedschema {
+  finish_test
+  return
+}
+
+forcedelete test.db2
+sqlite3 db2 test.db2
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z);
+  CREATE INDEX i1 ON t1(z);
+  PRAGMA schema_version;
+} {2}
+
+do_execsql_test -db db2 1.1 {
+  CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z);
+  CREATE INDEX i1 ON t1(z);
+  PRAGMA schema_version;
+} {2}
+
+do_test 1.2 {
+  db close
+  db2 close
+  sqlite3 db2 test.db2 -shared-schema 1
+  sqlite3 db  test.db -shared-schema 1
+} {}
+
+do_execsql_test -db db2 1.3.1 {
+  INSERT INTO t1 VALUES(1, 2, 3);
+  INSERT INTO t1 VALUES(4, 5, 6);
+}
+
+do_execsql_test 1.3.2 {
+  SELECT * FROM t1;
+  PRAGMA integrity_check;
+} {ok}
+
+do_execsql_test -db db2 1.3.3 {
+  SELECT * FROM t1;
+  PRAGMA integrity_check;
+} {1 2 3 4 5 6 ok}
+
+sqlite3 db3 test.db2
+do_execsql_test -db db3 1.4.1 {
+  ALTER TABLE t1 ADD COLUMN a;
+}
+do_execsql_test -db db2 1.4.2 {
+  SELECT * FROM t1;
+} {1 2 3 {} 4 5 6 {}}
+do_execsql_test 1.4.3 {
+  SELECT * FROM t1;
+} {}
+
+db3 close
+sqlite3 db3 test.db
+do_execsql_test -db db3 1.5.0 {
+  CREATE TRIGGER tr1 AFTER INSERT ON t1 BEGIN
+    SELECT 1, 2, 3;
+  END;
+}
+
+# Check that the schema cannot be modified if the db was opened with
+# SQLITE_OPEN_REUSE_SCHEMA.
+#
+foreach {tn sql} {
+  1  { CREATE TABLE t2(x, y) }
+  2  { CREATE INDEX i2 ON t1(z) }
+  3  { CREATE VIEW v2 AS SELECT * FROM t2 }
+  4  { ALTER TABLE t1 RENAME TO t3 }
+  5  { ALTER TABLE t1 ADD COLUMN xyz }
+  6  { VACUUM }
+  7  { DROP INDEX i1 }
+  8  { DROP TABLE t1 }
+  9  { DROP TRIGGER tr1 }
+  10 { ANALYZE }
+  11 { ALTER TABLE t1 RENAME z TO zzz }
+} {
+  do_catchsql_test 1.5.$tn $sql {1 {attempt to modify read-only schema}}
+}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+forcedelete test.db2
+ifcapable fts5 {
+  do_execsql_test 2.0 {
+    CREATE VIRTUAL TABLE ft USING fts5(a);
+    INSERT INTO ft VALUES('one'), ('two'), ('three');
+    ATTACH 'test.db2' AS aux;
+    CREATE VIRTUAL TABLE aux.ft USING fts5(a);
+    INSERT INTO aux.ft VALUES('aux1'), ('aux2'), ('aux3');
+  }
+
+  db close
+  sqlite3 db  test.db -shared-schema 1
+
+  do_execsql_test 2.1 {
+    ATTACH 'test.db2' AS aux;
+    SELECT * FROM main.ft;
+  } {one two three}
+
+breakpoint
+  do_execsql_test 2.2 {
+    SELECT * FROM aux.ft;
+  } {aux1 aux2 aux3}
+
+  do_execsql_test 2.2 {
+    SELECT * FROM aux.ft_content;
+  } {1 aux1 2 aux2 3 aux3}
+}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+forcedelete test.db2
+do_execsql_test 3.0 {
+  CREATE TABLE t1(a PRIMARY KEY, b, c);
+  CREATE VIEW v1 AS SELECT * FROM t1;
+  CREATE TRIGGER v1_ins INSTEAD OF INSERT ON v1 BEGIN
+    INSERT INTO t1 VALUES(new.a, new.b, new.c);
+  END;
+  CREATE TRIGGER v1_del INSTEAD OF DELETE ON v1 BEGIN
+    DELETE FROM t1 WHERE a=old.a;
+  END;
+  CREATE TRIGGER v1_up INSTEAD OF UPDATE ON v1 BEGIN
+    UPDATE t1 SET a=new.a, b=new.b, c=new.c WHERE a=old.a;
+  END;
+}
+forcecopy test.db test.db2
+
+do_test 3.1 {
+  sqlite3 db2 test.db2
+  execsql { INSERT INTO t1 VALUES(1, 2, 3) } db
+  execsql { INSERT INTO t1 VALUES(4, 5, 6) } db2
+  db2 close
+  execsql { ATTACH 'test.db2' AS aux; }
+} {}
+
+do_execsql_test 3.2 {
+  SELECT * FROM main.v1;
+} {1 2 3}
+
+do_execsql_test 3.3 {
+  SELECT * FROM aux.v1;
+} {4 5 6}
+
+db close
+sqlite3 db test.db -shared-schema 1
+
+do_execsql_test 3.4 { ATTACH 'test.db2' AS aux } {}
+do_execsql_test 3.5 { SELECT * FROM main.v1 } {1 2 3}
+do_execsql_test 3.6 { SELECT * FROM aux.v1  } {4 5 6}
+
+do_execsql_test 3.7.1 { INSERT INTO aux.t1 VALUES(8, 9, 10); }
+do_execsql_test 3.7.2 { SELECT * FROM main.v1 } {1 2 3}
+do_execsql_test 3.7.3 { SELECT * FROM aux.v1  } {4 5 6 8 9 10}
+
+do_execsql_test 3.8.1 { DELETE FROM aux.t1 WHERE b=5 }
+do_execsql_test 3.8.2 { SELECT * FROM main.v1 } {1 2 3}
+do_execsql_test 3.8.3 { SELECT * FROM aux.v1  } {8 9 10}
+
+do_execsql_test 3.9.1 { UPDATE aux.t1 SET b='abc' }
+do_execsql_test 3.9.2 { SELECT * FROM main.v1 } {1 2 3}
+do_execsql_test 3.9.3 { SELECT * FROM aux.v1  } {8 abc 10}
+
+do_execsql_test 3.10.1 { INSERT INTO aux.v1 VALUES(11, 12, 13) }
+do_execsql_test 3.10.2 { SELECT * FROM main.v1 } {1 2 3}
+do_execsql_test 3.10.3 { SELECT * FROM aux.v1  } {8 abc 10 11 12 13}
+
+do_execsql_test 3.11.1 { DELETE FROM aux.v1 WHERE b='abc' }
+do_execsql_test 3.11.2 { SELECT * FROM main.v1 } {1 2 3}
+do_execsql_test 3.11.3 { SELECT * FROM aux.v1  } {11 12 13}
+
+do_execsql_test 3.12.1 { UPDATE aux.v1 SET b='def' }
+do_execsql_test 3.12.2 { SELECT * FROM main.v1 } {1 2 3}
+do_execsql_test 3.12.3 { SELECT * FROM aux.v1  } {11 def 13}
+
+do_execsql_test 3.13.1 {
+  CREATE TEMP TRIGGER xyz AFTER INSERT ON aux.t1 BEGIN
+    INSERT INTO v1 VALUES(new.a, new.b, new.c);
+  END
+}
+do_execsql_test 3.13.2 {
+  INSERT INTO aux.v1 VALUES('x', 'y', 'z');
+}
+do_execsql_test 3.13.3 {
+  SELECT * FROM v1;
+} {1 2 3 x y z}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+forcedelete test.db2
+do_execsql_test 4.0 {
+  CREATE TABLE t1(a PRIMARY KEY, b, c UNIQUE);
+  CREATE TABLE del(a, b, c);
+  CREATE TRIGGER tr1 AFTER DELETE ON t1 BEGIN
+    INSERT INTO del VALUES(old.a, old.b, old.c);
+  END;
+}
+forcecopy test.db test.db2
+
+db close
+sqlite3 db test.db -shared-schema 1
+execsql { 
+  ATTACH 'test.db2' AS aux;
+  PRAGMA recursive_triggers = 1;
+}
+
+do_execsql_test 4.1 {
+  INSERT INTO main.t1 VALUES(1, 2, 3);
+  INSERT INTO aux.t1 VALUES(4, 5, 6);
+}
+
+do_execsql_test 4.2.1 {
+  INSERT OR REPLACE INTO aux.t1 VALUES('a', 'b', 6);
+  SELECT * FROM aux.t1;
+} {a b 6}
+do_execsql_test 4.2.2 { SELECT * FROM aux.del  } {4 5 6}
+do_execsql_test 4.2.3 { SELECT * FROM main.del } {}
+
+do_execsql_test 4.3.1 {
+  INSERT INTO aux.t1 VALUES('x', 'y', 'z');
+  UPDATE OR REPLACE aux.t1 SET c='z' WHERE a='a';
+} {}
+do_execsql_test 4.3.2 { SELECT * FROM aux.del  } {4 5 6 x y z}
+do_execsql_test 4.3.3 { SELECT * FROM main.del } {}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+do_execsql_test 5.0 {
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c);
+  CREATE TABLE t2(a INTEGER PRIMARY KEY, b, c);
+  CREATE INDEX i1 ON t1(b);
+  INSERT INTO t1 VALUES(1, 2, 3), (4, 5, 6);
+  ANALYZE;
+  PRAGMA writable_schema = 1;
+  DELETE FROM sqlite_stat1;
+}
+db close
+forcecopy test.db test.db2
+sqlite3 db test.db -shared-schema 1
+execsql { ATTACH 'test.db2' AS aux }
+
+foreach {tn sql} {
+  1 { CREATE TABLE t3(x) }
+  2 { DROP TABLE t2 }
+  3 { CREATE INDEX i2 ON t2(b) }
+  4 { DROP INDEX i1 }
+  5 { ALTER TABLE t1 ADD COLUMN d }
+  6 { ALTER TABLE t1 RENAME TO t3 }
+  7 { ALTER TABLE t1 RENAME c TO d }
+} {
+  do_catchsql_test 5.1.$tn $sql {1 {attempt to modify read-only schema}}
+}
+
+do_execsql_test 5.2.1 { ANALYZE aux.t1 } {}
+do_execsql_test 5.2.2 { SELECT * FROM aux.sqlite_stat1  } {t1 i1 {2 1}}
+do_execsql_test 5.2.3 { SELECT * FROM main.sqlite_stat1 } {}
+
+do_test 5.3.0 {
+  sqlite3 db2 test.db2
+  db2 eval { 
+    PRAGMA writable_schema = 1;
+    DELETE FROM sqlite_stat1;
+  }
+} {}
+
+do_execsql_test 5.3.1 { SELECT * FROM aux.sqlite_stat1  } {}
+do_execsql_test 5.3.2 { ANALYZE aux } {}
+do_execsql_test 5.3.3 { SELECT * FROM aux.sqlite_stat1  } {t1 i1 {2 1}}
+do_execsql_test 5.3.4 { SELECT * FROM main.sqlite_stat1 } {}
+
+#-------------------------------------------------------------------------
+# Attempting to run ANALYZE when the required sqlite_statXX functions
+# are missing is an error (because it would modify the database schema).
+#
+reset_db
+do_execsql_test 5.4 {
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c);
+  CREATE TABLE t2(a INTEGER PRIMARY KEY, b, c);
+  CREATE INDEX i1 ON t1(b);
+  INSERT INTO t1 VALUES(1, 2, 3), (4, 5, 6);
+}
+db close
+sqlite3 db test.db -shared-schema 1
+foreach {tn sql} {
+  1 { ANALYZE }
+  2 { ANALYZE t1 }
+  3 { ANALYZE i1 }
+  4 { ANALYZE main }
+  5 { ANALYZE main.t1 }
+  6 { ANALYZE main.i1 }
+} {
+  do_catchsql_test 5.4.$tn $sql {1 {attempt to modify read-only schema}}
+}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+do_execsql_test 6.0 {
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c);
+  CREATE VIEW v1 AS SELECT * FROM t1;
+}
+db close
+forcecopy test.db test.db2
+sqlite3 db test.db -shared-schema 1
+execsql { ATTACH 'test.db2' AS aux }
+
+do_execsql_test 6.1 {
+  INSERT INTO main.t1(a) VALUES(1), (2), (3);
+  INSERT INTO aux.t1(a) VALUES(4), (5), (6);
+  CREATE TEMP TABLE t2(i,t);
+  INSERT INTO t2 VALUES(2, 'two'), (5, 'five');
+}
+
+do_execsql_test 6.2 {
+  SELECT t FROM t2 WHERE i IN (SELECT a FROM aux.t1)
+} {five}
+do_execsql_test 6.3 {
+  SELECT t FROM t2 WHERE i IN (SELECT a FROM aux.v1)
+} {five}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+do_execsql_test 7.0 {
+  CREATE TABLE p1(a PRIMARY KEY, b);
+  CREATE TABLE p2(a PRIMARY KEY, b);
+  CREATE TABLE c1(x REFERENCES p1 ON UPDATE CASCADE ON DELETE CASCADE);
+}
+
+db close
+forcecopy test.db test.db2
+sqlite3 db test.db -shared-schema 1
+execsql { ATTACH 'test.db2' AS aux }
+
+do_execsql_test 7.1 {
+  INSERT INTO aux.p1 VALUES(1, 'one');
+  INSERT INTO aux.p1 VALUES(2, 'two');
+  PRAGMA foreign_keys = on;
+}
+
+do_execsql_test 7.2 {
+  INSERT INTO aux.c1 VALUES(2);
+}
+
+do_execsql_test 7.3.1 {
+  PRAGMA foreign_keys = off;
+  INSERT INTO main.p2 SELECT * FROM aux.p1;
+}
+do_execsql_test 7.3.2 {
+  SELECT * FROM main.p2;
+} {1 one 2 two}
+
+do_execsql_test 7.3.3 {
+  INSERT INTO aux.p2 VALUES(1, 2);
+}
+
+do_execsql_test 7.3.4 {
+  SELECT main.p2.a FROM main.p2, aux.p2;
+} {1 2}
+
+do_execsql_test 7.3.5 {
+  SELECT * FROM main.p2, aux.p2;
+} {1 one 1 2   2 two 1 2}
+
+do_execsql_test 7.4 {
+  SELECT count(*) FROM aux.p2;
+} {1}
+
+
+finish_test
+
+
@@ -0,0 +1,336 @@
+# 2017 August 9
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix reuse2
+
+ifcapable !sharedschema {
+  finish_test
+  return
+}
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z);
+  CREATE INDEX i1 ON t1(z);
+  PRAGMA schema_version;
+} {2}
+
+do_test 1.2 {
+  catch { db close }
+  catch { db2 close }
+  sqlite3 db2 test.db -shared-schema 1
+  sqlite3 db  test.db -shared-schema 1
+} {}
+
+do_execsql_test -db db2 1.3.1 {
+  INSERT INTO t1 VALUES(1, 2, 3);
+}
+
+do_execsql_test -db db2 1.3.2 {
+  INSERT INTO t1 VALUES(4, 5, 6);
+}
+
+do_execsql_test 1.3.3 {
+  SELECT * FROM t1;
+} {1 2 3 4 5 6}
+
+#--------------------------------------------------------------------------
+reset_db
+ifcapable fts5 {
+  do_execsql_test 2.0 {
+    CREATE VIRTUAL TABLE ft USING fts5(c);
+    INSERT INTO ft VALUES('one two three');
+  }
+  db close
+  sqlite3 db test.db -shared-schema 1
+
+  do_execsql_test 2.1 {
+    SELECT * FROM ft
+  } {{one two three}}
+}
+
+#--------------------------------------------------------------------------
+reset_db
+do_execsql_test 3.0 {
+  CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z);
+  CREATE INDEX i1 ON t1(z);
+  PRAGMA schema_version;
+} {2}
+
+do_test 3.1 {
+  sqlite3 db1 test.db -shared-schema 1
+  sqlite3 db2 test.db -shared-schema 1
+} {}
+
+do_execsql_test -db db1 3.2.1 { SELECT * FROM t1 }
+do_execsql_test -db db2 3.2.2 { SELECT * FROM t1 }
+
+register_schemapool_module db
+do_execsql_test 3.3 { 
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=2 nschema=1 ndelete=0}
+
+sqlite3 db3 test.db -shared-schema 1
+register_schemapool_module db3
+
+do_execsql_test 3.5 { 
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=2 nschema=1 ndelete=0}
+
+do_execsql_test -db db3 3.6 { 
+  SELECT * FROM t1;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=3 nschema=1 ndelete=0}
+
+do_execsql_test 3.7 { 
+  CREATE TABLE t2(x);
+}
+
+do_execsql_test 3.8 { 
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=3 nschema=1 ndelete=0}
+
+do_execsql_test -db db1 3.9.1 { SELECT * FROM t1 }
+do_execsql_test 3.9.2 { 
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=1 nschema=1 ndelete=0 nref=2 nschema=1 ndelete=0}
+
+do_execsql_test -db db2 3.10.1 { SELECT * FROM t1 }
+do_execsql_test 3.10.2 { 
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool ORDER BY 1;
+} {nref=1 nschema=1 ndelete=0 nref=2 nschema=1 ndelete=0}
+
+do_execsql_test -db db3 3.11.1 { SELECT * FROM t1 }
+do_execsql_test 3.11.2 { 
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=3 nschema=1 ndelete=0}
+
+#--------------------------------------------------------------------------
+catch {db1 close}
+catch {db2 close}
+catch {db3 close}
+reset_db
+do_execsql_test 4.0.1 {
+  CREATE TABLE x1(a, b, c);
+  CREATE INDEX x1a ON x1(a);
+  CREATE INDEX x1b ON x1(b);
+}
+do_test 4.0.2 {
+  db close
+  for {set i 1} {$i < 6} {incr i} {
+    forcedelete test.db${i}-journal test.db${i}-wal test.db${i}-wal2 
+    forcecopy test.db test.db${i}
+  }
+  sqlite3 db  test.db
+  sqlite3 db2 test.db -shared-schema 1
+} {}
+
+register_schemapool_module db
+do_execsql_test 4.0.3 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {}
+
+do_test 4.1.1 {
+  execsql { 
+    ATTACH 'test.db1' AS db1; 
+    ATTACH 'test.db2' AS db2;
+    ATTACH 'test.db3' AS db3;
+    ATTACH 'test.db4' AS db4;
+    ATTACH 'test.db5' AS db5;
+  } db2
+} {}
+do_execsql_test 4.1.2 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {}
+do_execsql_test -db db2 4.1.3 {
+  SELECT * FROM db3.x1
+}
+do_execsql_test 4.1.4 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=1 nschema=1 ndelete=0}
+do_execsql_test -db db2 4.1.5 {
+  SELECT * FROM db2.x1
+}
+do_execsql_test 4.1.6 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=2 nschema=1 ndelete=0}
+do_execsql_test -db db2 4.1.7 {
+  SELECT * FROM x1
+}
+do_execsql_test 4.1.8 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=6 nschema=1 ndelete=0}
+
+do_test 4.2.1 {
+  catchsql { SELECT * FROM abc } db2
+} {1 {no such table: abc}}
+do_execsql_test 4.2.2 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=6 nschema=1 ndelete=0}
+
+register_schemapool_module db2
+do_execsql_test -db db2 4.3.1 {
+  INSERT INTO x1 VALUES(1, 2, 3);
+  INSERT INTO db1.x1 VALUES(4, 5, 6);
+  INSERT INTO db2.x1 VALUES(7, 8, 9);
+  INSERT INTO db3.x1 VALUES(10, 11, 12);
+  INSERT INTO db4.x1 VALUES(13, 14, 15);
+  INSERT INTO db5.x1 VALUES(16, 17, 18);
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=6 nschema=1 ndelete=0}
+
+do_execsql_test -db db2 4.3.2 {
+  SELECT * FROM db5.x1;
+  SELECT * FROM db4.x1;
+  SELECT * FROM db3.x1;
+  SELECT * FROM db2.x1;
+  SELECT * FROM db1.x1;
+  SELECT * FROM x1;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {
+  16 17 18  13 14 15  10 11 12  7 8 9  4 5 6  1 2 3
+  nref=6 nschema=1 ndelete=0
+}
+
+do_execsql_test -db db2 4.3.3 {
+  UPDATE x1 SET a=a+10;
+  UPDATE db5.x1 SET a=a+10;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {
+  nref=6 nschema=1 ndelete=0
+}
+
+do_execsql_test -db db2 4.3.4 {
+  SELECT * FROM db5.x1;
+  SELECT * FROM db4.x1;
+  SELECT * FROM db3.x1;
+  SELECT * FROM db2.x1;
+  SELECT * FROM db1.x1;
+  SELECT * FROM x1;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {
+  26 17 18  13 14 15  10 11 12  7 8 9  4 5 6  11 2 3
+  nref=6 nschema=1 ndelete=0
+}
+
+do_execsql_test -db db2 4.3.5 {
+  DELETE FROM db3.x1;
+  DELETE FROM x1;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {
+  nref=6 nschema=1 ndelete=0
+}
+
+do_execsql_test -db db2 4.3.6 {
+  SELECT * FROM db5.x1;
+  SELECT * FROM db4.x1;
+  SELECT * FROM db3.x1;
+  SELECT * FROM db2.x1;
+  SELECT * FROM db1.x1;
+  SELECT * FROM x1;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {
+  26 17 18  13 14 15  7 8 9  4 5 6 
+  nref=6 nschema=1 ndelete=0
+}
+
+do_execsql_test -db db2 4.3.6 {
+  SELECT * FROM db5.x1, db4.x1, db1.x1;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {26 17 18 13 14 15 4 5 6 nref=6 nschema=3 ndelete=0}
+
+#--------------------------------------------------------------------------
+# Test the incremental-blob API with REUSE_SCHEMA connections.
+#
+catch {db1 close}
+catch {db2 close}
+catch {db3 close}
+reset_db
+do_execsql_test 5.0.1 {
+  CREATE TABLE bbb(a INTEGER PRIMARY KEY, b);
+}
+db close
+do_test 5.0.2 {
+  sqlite3 db2 test.db -shared-schema 1
+  register_schemapool_module db2
+  for {set i 1} {$i<6} {incr i} {
+    forcedelete test.db${i}-journal test.db${i}-wal test.db${i}-wal2 
+    forcecopy test.db test.db${i}
+    sqlite3 db test.db${i}
+    db eval { INSERT INTO bbb VALUES(123, 'database_' || $i) }
+    db close
+    db2 eval "ATTACH 'test.db${i}' AS db${i}"
+  }
+  execsql {
+    SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+      FROM schemapool;
+  } db2
+} {nref=6 nschema=1 ndelete=0}
+
+do_test 5.1.1 {
+  set res [list]
+  for {set i 1} {$i<6} {incr i} {
+    set chan [db2 incrblob db${i} bbb b 123]
+    lappend res [gets $chan]
+    close $chan
+  }
+  set res
+} {database_1 database_2 database_3 database_4 database_5}
+
+do_execsql_test -db db2 5.1.2 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=6 nschema=1 ndelete=0}
+
+do_test 5.2.1 {
+  sqlite3_table_column_metadata db2 main bbb a
+} {INTEGER BINARY 0 1 0}
+do_test 5.2.2 {
+  sqlite3_table_column_metadata db2 main bbb b
+} {{} BINARY 0 0 0}
+
+do_execsql_test -db db2 5.2.3 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {nref=6 nschema=1 ndelete=0}
+
+do_execsql_test -db db2 5.2.4 {
+  PRAGMA integrity_check;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete
+  FROM schemapool;
+} {ok nref=6 nschema=1 ndelete=5}
+
+finish_test
+
@@ -0,0 +1,355 @@
+# 2019 February 12
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix reuse3
+
+ifcapable !sharedschema {
+  finish_test
+  return
+}
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z);
+  CREATE INDEX i1 ON t1(z);
+  CREATE TABLE t2(a);
+} {}
+
+db close
+sqlite3 db test.db -shared-schema 1
+
+do_execsql_test 1.1 {
+  CREATE TEMP VIEW v1 AS SELECT * FROM t1;
+  SELECT * FROM v1;
+}
+
+do_execsql_test 1.2 {
+  CREATE TEMP TRIGGER tr1 AFTER INSERT ON t1 BEGIN
+    INSERT INTO t2 VALUES(new.x);
+  END;
+}
+
+do_execsql_test 1.3 {
+  INSERT INTO t1 VALUES(1, 2, 3);
+}
+
+do_execsql_test 1.4 {
+  SELECT * FROM t2
+} {1}
+
+do_execsql_test 1.5 {
+  SELECT * FROM v1
+} {1 2 3}
+
+do_execsql_test 1.6 {
+  BEGIN;
+    DROP TRIGGER tr1;
+  ROLLBACK;
+}
+
+do_execsql_test 1.7 {
+  SELECT * FROM v1
+} {1 2 3}
+
+do_execsql_test 1.8 {
+  INSERT INTO t1 VALUES(4, 5, 6);
+  SELECT * FROM t2
+} {1 4}
+
+do_execsql_test 1.9 {
+  SELECT * FROM v1
+} {1 2 3 4 5 6}
+
+#-------------------------------------------------------------------------
+# Test error messages when parsing the schema with a REUSE_SCHEMA 
+# connection.
+reset_db
+do_execsql_test 2.0 {
+  CREATE TABLE x1(a, b, c);
+  CREATE TABLE y1(d, e, f);
+  PRAGMA writable_schema = 1;
+  UPDATE sqlite_master SET sql = 'CREATE TBL y1(d, e, f)' WHERE name = 'y1';
+}
+db close
+
+sqlite3 db test.db -shared-schema 1
+do_catchsql_test 2.1 {
+  SELECT * FROM x1;
+} {1 {malformed database schema (y1) - near "TBL": syntax error}}
+
+do_catchsql_test 2.2 {
+  SELECT * FROM x1;
+} {1 {malformed database schema (y1) - near "TBL": syntax error}}
+
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 3.0 {
+  CREATE TABLE x1(a, b, c);
+  CREATE INDEX i1 ON x1(a, b, c);
+  CREATE TRIGGER tr1 AFTER INSERT ON x1 BEGIN
+    SELECT 1, 2, 3, 4, 5;
+  END;
+  INSERT INTO x1 VALUES(1, 2, 3);
+}
+sqlite3 db1 test.db -shared-schema 1
+
+do_test 3.1 {
+  execsql { SELECT * FROM x1 } db1
+  set N [lindex [sqlite3_db_status db1 SCHEMA_USED 0] 1]
+  expr $N==$N
+} 1
+
+sqlite3 db2 test.db -shared-schema 1
+do_test 3.2 {
+  execsql { SELECT * FROM x1 } db2
+  set N2 [lindex [sqlite3_db_status db2 SCHEMA_USED 0] 1]
+  expr $N2>($N/2) && $N2<($N/2)+400
+} 1
+
+sqlite3 db3 test.db -shared-schema 1
+sqlite3 db4 test.db -shared-schema 1
+do_test 3.3 {
+  execsql { SELECT * FROM x1 } db3
+  execsql { SELECT * FROM x1 } db4
+  set N4 [lindex [sqlite3_db_status db2 SCHEMA_USED 0] 1]
+  set M [expr 2*($N-$N2)]
+  set {} {}
+} {}
+do_test 3.3.1 { expr {(($M / 4) + $N-$M)} } "#/$N4/"
+
+catch { db1 close }
+catch { db2 close }
+catch { db3 close }
+catch { db4 close }
+
+#-------------------------------------------------------------------------
+# 4.1 Test the REINDEX command.
+# 4.2 Test CREATE TEMP ... commands.
+#
+reset_db
+do_execsql_test 4.1.0 {
+  CREATE TABLE x1(a, b, c);
+  CREATE INDEX x1a ON x1(a);
+  CREATE INDEX x1b ON x1(b);
+  CREATE INDEX x1c ON x1(c);
+}
+db close
+sqlite3 db test.db -shared-schema 1
+
+do_execsql_test 4.1.1 {
+  REINDEX x1;
+  REINDEX x1a;
+  REINDEX x1b;
+  REINDEX x1c;
+  REINDEX;
+}
+
+do_test 4.1.2 {
+  for {set i 1} {$i < 5} {incr i} {
+    forcedelete test.db${i} test.db${i}-wal test.db${i}-journal
+    forcecopy test.db test.db${i}
+    execsql "ATTACH 'test.db${i}' AS db${i}"
+  }
+  register_schemapool_module db
+  set {} {}
+  execsql { 
+    SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool 
+  }
+} {nref=5 nschema=1 ndelete=0}
+
+do_execsql_test 4.1.3 {
+  REINDEX  x1;
+  REINDEX  x1a;
+  REINDEX  x1b;
+  REINDEX  x1c;
+  REINDEX  db1.x1a;
+  REINDEX  db2.x1b;
+  REINDEX  db3.x1c;
+}
+
+do_execsql_test 4.1.4 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool 
+} {nref=5 nschema=1 ndelete=28}
+
+#-------------------------------------------------------------------------
+db close
+sqlite3 db test.db -shared-schema 1
+register_schemapool_module db
+do_execsql_test 4.2.0 {
+  ATTACH 'test.db1' AS db1;
+  ATTACH 'test.db2' AS db2;
+  ATTACH 'test.db3' AS db3;
+  ATTACH 'test.db4' AS db4;
+
+  SELECT * FROM db1.x1;
+  SELECT * FROM db2.x1;
+  SELECT * FROM db3.x1;
+  SELECT * FROM db4.x1;
+}
+
+do_execsql_test 4.2.1 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool; 
+} {nref=5 nschema=1 ndelete=0}
+
+do_execsql_test 4.2.2 {
+  CREATE TEMP TABLE t1(a, b, c);
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool; 
+} {nref=5 nschema=1 ndelete=0}
+
+do_execsql_test 4.2.3 {
+  CREATE INDEX t1a ON t1(a);
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool; 
+} {nref=5 nschema=1 ndelete=0}
+
+do_execsql_test 4.2.4 {
+  CREATE TRIGGER tr1 AFTER INSERT ON t1 BEGIN
+    SELECT 1,2,3,4;
+  END;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool; 
+} {nref=5 nschema=1 ndelete=0}
+
+do_execsql_test 4.2.5 {
+  DROP TABLE t1;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool; 
+} {nref=5 nschema=1 ndelete=0}
+
+do_execsql_test 4.2.6 {
+  CREATE TEMP TRIGGER tr1 AFTER INSERT ON db2.x1 BEGIN
+    SELECT 1,2,3,4;
+  END;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool; 
+} {nref=5 nschema=1 ndelete=0}
+
+do_execsql_test 4.2.7 {
+  DROP TRIGGER tr1;
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema, 'ndelete=' || nDelete 
+    FROM schemapool; 
+} {nref=5 nschema=1 ndelete=4}
+
+#--------------------------------------------------------------------------
+reset_db
+do_execsql_test 5.0 {
+  CREATE TABLE t1(a, b);
+  CREATE TABLE t2(a, b);
+  CREATE TABLE t3(a, b);
+}
+
+sqlite3 db2 test.db -shared-schema 1
+register_schemapool_module db2
+
+do_execsql_test 5.1 {
+  PRAGMA writable_schema = 1;
+  UPDATE sqlite_master SET sql='CREATE TABLE t3 a,b' WHERE name = 't3';
+}
+
+do_test 5.2 { 
+  catchsql { SELECT * FROM t1 } db2
+} {1 {malformed database schema (t3) - near "a": syntax error}}
+
+do_test 5.3 { 
+  catchsql { SELECT nref,nschema FROM schemapool } db2
+} {1 {vtable constructor failed: schemapool}}
+
+do_execsql_test 5.4 {
+  PRAGMA writable_schema = 1;
+  UPDATE sqlite_master SET sql='CREATE TABLE t3(a,b)' WHERE name = 't3';
+}
+
+do_test 5.5 { 
+  catchsql { SELECT nref,nschema FROM schemapool } db2
+} {0 {1 1}}
+
+db2 close
+db close
+do_test 5.6.1 {
+  forcedelete test.db2 test.db2-wal test.db2-journal
+  forcecopy test.db test.db2
+  sqlite3 db test.db
+  sqlite3 db2 test.db  -shared-schema 1
+  sqlite3 db3 test.db2 -shared-schema 1
+  register_schemapool_module db
+} {}
+
+do_execsql_test -db db2 5.6.2 { SELECT * FROM t1 }
+do_execsql_test -db db3 5.6.3 { SELECT * FROM t1 }
+do_execsql_test 5.6.4 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema FROM schemapool; 
+  CREATE TABLE t4(x);
+  DROP TABLE t4;
+} {nref=2 nschema=1}
+do_execsql_test -db db2 5.6.5 { SELECT * FROM t1 }
+do_execsql_test -db db3 5.6.6 { SELECT * FROM t1 }
+do_execsql_test 5.6.7 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema FROM schemapool; 
+  ATTACH 'test.db2' AS db2;
+  CREATE TABLE db2.t4(x);
+  DROP TABLE db2.t4;
+} {nref=1 nschema=1 nref=1 nschema=1}
+do_execsql_test -db db2 5.6.8 { SELECT * FROM t1 }
+do_execsql_test -db db3 5.6.9 { SELECT * FROM t1 }
+do_execsql_test 5.6.10 {
+  SELECT 'nref=' || nRef, 'nschema=' || nSchema FROM schemapool; 
+} {nref=2 nschema=1}
+
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 6.0 {
+  CREATE TABLE t1(a, b);
+  CREATE TABLE t2(a, b);
+  CREATE TABLE t3(a, b);
+}
+
+do_test 6.1 {
+  db close
+  sqlite3 db test.db -shared-schema 1
+  for {set i 1} {$i < 5} {incr i} {
+    set base "test.db$i"
+    set nm "aux$i"
+    forcedelete $base $base-wal $base-journal
+    forcecopy test.db $base
+    execsql "ATTACH '$base' AS $nm"
+  }
+} {}
+
+do_test 6.2 {
+  set N1 [lindex [sqlite3_db_status db SCHEMA_USED 0] 1]
+  set N2 [lindex [sqlite3_db_status db SCHEMA_USED 0] 1]
+  expr ($N1==0 && $N2==0)
+} {1}
+
+do_test 6.3 {
+  execsql { SELECT * FROM main.t1 }
+  set N1 [lindex [sqlite3_db_status db SCHEMA_USED 0] 1]
+  set N2 [lindex [sqlite3_db_status db SCHEMA_USED 0] 1]
+  expr {$N1>0 && $N2>0 && $N1==$N2}
+} {1}
+
+do_test 6.4 {
+  execsql { SELECT * FROM aux1.t1 }
+  set N3 [lindex [sqlite3_db_status db SCHEMA_USED 0] 1]
+  set N4 [lindex [sqlite3_db_status db SCHEMA_USED 0] 1]
+  list $N3 $N4
+} "#/$N1 $N1/"
+
+finish_test
+
@@ -0,0 +1,173 @@
+# 2019 February 12
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix reuse4
+
+ifcapable !sharedschema {
+  finish_test
+  return
+}
+
+foreach {tn sharedschema} {
+  1 0  
+  2 1  
+} {
+  reset_db
+
+  do_execsql_test 1.$tn.0 {
+    CREATE TABLE x1(a, b);
+    CREATE INDEX x1a ON x1(a);
+    CREATE INDEX x1b ON x1(b);
+    CREATE TABLE x2(a, b);
+  }
+  db close
+  
+  do_test 1.$tn.1 {
+    for {set i 1} {$i<4} {incr i} {
+      forcedelete test.db$i test.db$i-journal test.db$i-wal
+      forcecopy test.db test.db$i
+    }
+  
+    sqlite3 db test.db -shared-schema $sharedschema
+    for {set i 1} {$i<4} {incr i} {
+      execsql " ATTACH 'test.db$i' AS db$i "
+    }
+  } {}
+  
+  do_execsql_test 1.$tn.2 {
+    WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<10 )
+    INSERT INTO x1 SELECT i, i FROM s;
+  
+    INSERT INTO db3.x2 SELECT * FROM x1;
+    INSERT INTO db2.x1 SELECT * FROM db3.x2;
+    CREATE TEMP TRIGGER tr1 AFTER INSERT ON db2.x2 BEGIN
+      INSERT INTO x1 VALUES(new.a, new.b);
+    END;
+    INSERT INTO db2.x2 SELECT * FROM x1 WHERE a%2;
+    DELETE FROM x1 WHERE a<3;
+    INSERT INTO db3.x1 SELECT * FROM db2.x2;
+  
+    DETACH db3;
+    ATTACH 'test.db3' AS db3;
+  
+    UPDATE db3.x1 SET a=a-10 WHERE b NOT IN (SELECT b FROM db2.x2);
+  
+    CREATE TEMP TABLE x1(a, b);
+    INSERT INTO db2.x2 VALUES(50, 60), (60, 70), (80, 90);
+    ALTER TABLE x1 RENAME TO x2;
+    ALTER TABLE x2 ADD COLUMN c;
+    ALTER TABLE x2 RENAME a TO aaa;
+    DELETE FROM x1 WHERE b>8;
+    UPDATE db3.x2 SET b=b*10;
+  
+    BEGIN;
+      CREATE TEMP TABLE x5(x);
+      INSERT INTO x5 VALUES(1);
+    ROLLBACK;
+  
+    INSERT INTO main.x2 VALUES(123, 456);
+  }
+  
+  integrity_check 1.$tn.3
+  
+  do_execsql_test 1.$tn.4 {
+    SELECT * FROM main.x1; SELECT 'xxx';
+    SELECT * FROM main.x2; SELECT 'xxx';
+    SELECT * FROM temp.x2; SELECT 'xxx';
+  
+    SELECT * FROM db1.x1; SELECT 'xxx';
+    SELECT * FROM db1.x2; SELECT 'xxx';
+    SELECT * FROM db2.x1; SELECT 'xxx';
+    SELECT * FROM db2.x2; SELECT 'xxx';
+    SELECT * FROM db3.x1; SELECT 'xxx';
+    SELECT * FROM db3.x2; SELECT 'xxx';
+  } {
+    3 3 4 4 5 5 6 6 7 7 8 8 3 3 5 5 7 7 xxx 
+    123 456 xxx 
+    50 60 {} 60 70 {} 80 90 {} xxx
+    xxx
+    xxx
+    1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 xxx
+    1 1 3 3 5 5 7 7 9 9 50 60 60 70 80 90 xxx
+    1 1 3 3  5 5 7 7 9 9 xxx 
+    1 10 2 20 3 30 4 40 5 50 6 60 7 70 8 80 9 90 10 100 xxx
+  }
+  
+  do_test 1.$tn.5.1 {
+    sqlite3 db2 test.db
+    db2 eval { CREATE TABLE x3(x) }
+  } {}
+  do_execsql_test 1.$tn.5.2 {
+    SELECT * FROM main.x1; SELECT 'xxx';
+    SELECT * FROM main.x2; SELECT 'xxx';
+    SELECT * FROM main.x3; SELECT 'xxx';
+  } {
+    3 3 4 4 5 5 6 6 7 7 8 8 3 3 5 5 7 7 xxx 
+    123 456 xxx 
+    xxx
+  }
+}
+
+#-------------------------------------------------------------------------
+# Test some PRAGMA statements with shared-schema connections.
+#
+reset_db
+do_execsql_test 2.0 {
+  CREATE TABLE t1(a, b, c);
+  CREATE INDEX t1abc ON t1(a, b, c);
+}
+
+foreach {tn pragma nSchema nDelete} {
+  1 "PRAGMA synchronous = OFF"     1 0
+  2 "PRAGMA cache_size = 200"      1 0
+  3 "PRAGMA aux2.integrity_check"  1 0
+  4 "PRAGMA      integrity_check"  1 5
+  5 "PRAGMA index_info=t1abc"      1 5
+  6 "PRAGMA aux3.index_info=t1abc" 1 0
+  7 "PRAGMA journal_mode"          1 0
+  8 "PRAGMA aux2.wal_checkpoint"   1 0
+  9 "PRAGMA wal_checkpoint"        1 0
+} {
+  do_test 2.$tn.1 {
+    catch { db close }
+    catch { db2 close }
+    for {set i 1} {$i < 6} {incr i} {
+      forcedelete "test.db$i" "test.db${i}-wal" "test.db${i}-journal"
+      forcecopy test.db test.db$i
+    }
+    sqlite3 db2 test.db -shared-schema 1
+    for {set i 1} {$i < 6} {incr i} {
+      execsql "ATTACH 'test.db$i' AS aux$i" db2
+    }
+  } {}
+
+  sqlite3 db test.db
+  register_schemapool_module db
+
+  do_test 2.$tn.2 {
+    execsql $pragma db2
+    execsql { SELECT 'nschema='||nschema, 'ndelete='||nDelete FROM schemapool }
+  } "nschema=$nSchema ndelete=$nDelete"
+
+  do_test 2.$tn.3 {
+    execsql {
+      SELECT * FROM main.t1,aux1.t1,aux2.t1,aux3.t1,aux4.t1,aux5.t1
+    } db2
+    execsql { SELECT 'nschema=' || nschema, 'nref=' || nref FROM schemapool }
+  } "nschema=6 nref=6"
+}
+
+finish_test
+
@@ -0,0 +1,125 @@
+# 2019 February 26
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix reuse5
+set CLI [test_find_cli]
+
+ifcapable !sharedschema {
+  finish_test
+  return
+}
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(x, y);
+  CREATE TABLE t2(a, b, c);
+  CREATE INDEX t1x ON t1(x);
+  CREATE INDEX t1y ON t1(y);
+  CREATE VIEW v1 AS SELECT * FROM t2;
+}
+
+foreach {tn sql out1 out2} {
+  1 {
+    CREATE TABLE t1(x, y);
+    CREATE TABLE t2(a, b, c);
+    CREATE INDEX t1x ON t1(x);
+    CREATE INDEX t1y ON t1(y);
+    CREATE VIEW v1 AS SELECT * FROM t2;
+  } {
+    test.db2 is compatible
+  } {}
+
+  2 {
+    CREATE TABLE t1(x, y);
+    CREATE TABLE t2(a, b, c);
+    CREATE INDEX t1x ON t1(x);
+    CREATE INDEX t1y ON t1(y);
+    CREATE VIEW v1 AS SELECT * FROM t2;
+    CREATE TABLE x1(x);
+    DROP TABLE x1;
+  } {
+    test.db2 is NOT compatible (schema cookie)
+  } {
+    Fixing test.db2... test.db2 is compatible
+  }
+
+  3 {
+    CREATE TABLE t1(x, y);
+    CREATE TABLE t2(a, b, c);
+    CREATE INDEX t1y ON t1(y);
+    CREATE VIEW v1 AS SELECT * FROM t2;
+  } {
+    test.db2 is NOT compatible (objects)
+  } {}
+
+  4 {
+    CREATE TABLE t1(x, y);
+    CREATE TABLE t2(a, b, c);
+    CREATE INDEX t1x ON t1(X);
+    CREATE INDEX t1y ON t1(y);
+    CREATE VIEW v1 AS SELECT * FROM t2;
+  } {
+    test.db2 is NOT compatible (SQL)
+  } {}
+
+  5 {
+    CREATE TABLE t1(x, y);
+    CREATE TABLE t2(a, b, c);
+    CREATE INDEX t1y ON t1(y);
+    CREATE INDEX t1x ON t1(x);
+    CREATE VIEW v1 AS SELECT * FROM t2;
+  } {
+    test.db2 is NOT compatible (root pages)
+  } {
+    Fixing test.db2... test.db2 is compatible
+  }
+
+  6 {
+    CREATE TABLE t1(x, y);
+    CREATE TABLE t2(a, b, c);
+    CREATE INDEX t1x ON t1(x);
+    CREATE INDEX t1y ON t1(y);
+    CREATE VIEW v1 AS SELECT * FROM t2;
+    DROP INDEX t1x;
+    CREATE INDEX t1x ON t1(x);
+  } {
+    test.db2 is NOT compatible (order of sqlite_master rows)
+  } {
+    Fixing test.db2... test.db2 is compatible
+  }
+
+} {
+  forcedelete test.db2
+  sqlite3 db2 test.db2
+  db2 eval $sql
+  db2 close
+
+  if {$out2==""} {set out2 $out1}
+
+  do_test 1.$tn.1 {
+    catchcmd test.db ".shared-schema check test.db2"
+  } [list 0 [string trim $out1]]
+
+  do_test 1.$tn.2 {
+    catchcmd test.db ".shared-schema fix test.db2"
+  } [list 0 [string trim $out2]]
+
+  do_test 1.$tn.3 {
+    catchcmd test.db2 "PRAGMA integrity_check"
+  } [list 0 ok]
+}
+
+
+finish_test
+
@@ -0,0 +1,143 @@
+# 2019 February 26
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix reuse6
+
+ifcapable !sharedschema {
+  finish_test
+  return
+}
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(x, y);
+  CREATE TABLE t2(a, b, c);
+  CREATE INDEX t1x ON t1(x);
+  CREATE INDEX t1y ON t1(y);
+  CREATE VIEW v1 AS SELECT * FROM t2;
+
+  INSERT INTO t1 VALUES(1, 2), (3, 4), (5, 6);
+  INSERT INTO t2 VALUES('a', 'b', 'c'), ('d', 'e', 'f'), ('g', 'h', 'i');
+
+  ATTACH 'test.db2' AS aux;
+  CREATE TABLE t3(i, ii);
+  INSERT INTO t3 VALUES(10, 20);
+}
+
+sqlite3 db1 test.db -shared-schema 1
+sqlite3 db2 test.db -shared-schema 1
+
+do_execsql_test -db db1 1.1 {
+  ATTACH 'test.db2' AS aux;
+}
+
+do_test 1.2 {
+  execsql {SELECT * FROM t3} db1
+} {10 20}
+
+do_execsql_test -db db2 1.3 {
+  ATTACH 'test.db2' AS aux;
+}
+
+do_test 1.3 {
+  execsql {SELECT * FROM t3} db1
+} {10 20}
+
+do_execsql_test -db db2 1.5 {
+  SELECT * FROM t3;
+} {10 20}
+
+do_test 1.6 {
+  execsql {SELECT * FROM t3} db1
+} {10 20}
+
+db1 close
+db2 close
+
+#-------------------------------------------------------------------------
+reset_db
+forcedelete test.db2
+forcedelete test.db3
+do_execsql_test 2.0 {
+  CREATE TABLE t1(x, y);
+  ATTACH 'test.db2' AS aux2;
+  CREATE TABLE aux2.t2(x, y);
+  ATTACH 'test.db3' AS aux3;
+  CREATE TABLE aux3.t3(x, y);
+}
+
+sqlite3 db1 test.db -shared-schema 1
+do_execsql_test -db db1 2.1 {
+  ATTACH 'test.db2' AS aux2;
+  ATTACH 'test.db3' AS aux3;
+}
+
+do_test 2.2.1 {
+  catchsql { SELECT * FROM aux2.nosuchtable } db1
+} {1 {no such table: aux2.nosuchtable}}
+do_test 2.2.2 {
+  sqlite3_errcode db1
+} {SQLITE_ERROR}
+db1 close
+
+#-------------------------------------------------------------------------
+reset_db
+forcedelete test.db2
+ifcapable fts5 {
+  do_execsql_test 3.0 {
+    CREATE VIRTUAL TABLE ft USING fts5(a, b);
+    ATTACH 'test.db2' AS aux;
+    CREATE TABLE aux.t1(x, y, z);
+  }
+
+  sqlite3 db1 test.db -shared-schema 1
+  do_execsql_test -db db1 3.1 {
+    ATTACH 'test.db2' AS aux;
+  }
+
+  do_execsql_test -db db1 3.2 {
+    SELECT * FROM main.ft, aux.t1;
+  }
+  db1 close
+}
+
+#-------------------------------------------------------------------------
+reset_db
+forcedelete test.db2
+ifcapable fts5 {
+  do_execsql_test 4.0 {
+    CREATE VIRTUAL TABLE ft USING fts5(a, b);
+  }
+  forcecopy test.db test.db2
+
+  sqlite3 db1 test.db -shared-schema 1
+  do_execsql_test -db db1 4.1 {
+    ATTACH 'test.db2' AS aux;
+    SELECT * FROM main.ft;
+    SELECT * FROM aux.ft;
+  }
+
+  do_execsql_test -db db1 4.2 {
+    SELECT * FROM main.ft, aux.ft
+  }
+}
+
+
+
+
+
+
+
+finish_test
+
@@ -0,0 +1,54 @@
+# 2019 February 12
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix reusefault
+
+ifcapable !sharedschema {
+  finish_test
+  return
+}
+
+do_execsql_test 1.0 {
+  PRAGMA cache_size = 10;
+  CREATE TABLE t1(a UNIQUE, b UNIQUE);
+  INSERT INTO t1 VALUES(1, 2), (3, 4);
+}
+faultsim_save_and_close
+
+do_faultsim_test 1.1 -prep {
+  faultsim_restore
+  sqlite3 db test.db -shared-schema 1
+} -body {
+  execsql { SELECT * FROM t1 }
+} -test {
+  faultsim_test_result {0 {1 2 3 4}}
+}
+
+do_faultsim_test 1.2 -prep {
+  faultsim_restore
+  sqlite3 db test.db -shared-schema 1
+  execsql { SELECT * FROM t1 }
+  sqlite3 db2 test.db
+  db2 eval {CREATE TABLE a(a)}
+  db2 close
+} -body {
+  execsql { SELECT  * FROM t1 }
+} -test {
+  faultsim_test_result {0 {1 2 3 4}}
+}
+
+
+finish_test
+
@@ -751,4 +751,35 @@ do_execsql_test 32.1 {
  WHERE a=1234 OR a<=567;
 } {500 502}

+# 2022-07-15
+# https://sqlite.org/forum/forumpost/3607259d3c
+#
+reset_db
+do_execsql_test 33.1 {
+  CREATE TABLE t1(a INT, b INT PRIMARY KEY) WITHOUT ROWID;
+  INSERT INTO t1(a, b) VALUES (0, 1),(15,-7),(3,100);
+  ANALYZE;
+} {}
+do_execsql_test 33.2 {
+  SELECT * FROM t1 WHERE (b,a) BETWEEN (0,5) AND (99,-2);
+} {0 1}
+do_execsql_test 33.3 {
+  SELECT * FROM t1 WHERE (b,a) BETWEEN (-8,5) AND (0,-2);
+} {15 -7}
+do_execsql_test 33.3 {
+  SELECT * FROM t1 WHERE (b,a) BETWEEN (3,5) AND (100,4);
+} {3 100}
+do_execsql_test 33.3 {
+  SELECT * FROM t1 WHERE (b,a) BETWEEN (3,5) AND (100,2);
+} {}
+do_execsql_test 33.3 {
+  SELECT * FROM t1 WHERE (a,b) BETWEEN (-2,99) AND (1,0);
+} {0 1}
+do_execsql_test 33.3 {
+  SELECT * FROM t1 WHERE (a,b) BETWEEN (14,99) AND (16,0);
+} {15 -7}
+do_execsql_test 33.3 {
+  SELECT * FROM t1 WHERE (a,b) BETWEEN (2,99) AND (4,0);
+} {3 100}
+
 finish_test
@@ -118,10 +118,18 @@ do_test select3-2.14 {
 } {1 {near ";": syntax error}}

 # Cannot have a HAVING without a GROUP BY
+# 
+# Update: As of 3.39.0, you can.
 #
 do_execsql_test select3-3.1 {
  SELECT log, count(*) FROM t1 HAVING log>=4
 } {}
+do_execsql_test select3-3.2 {
+  SELECT count(*) FROM t1 HAVING log>=4
+} {}
+do_execsql_test select3-3.3 {
+  SELECT count(*) FROM t1 HAVING log!=400
+} {31}

 # Toss in some HAVING clauses
 #
@@ -26,6 +26,9 @@ set testprefix tcl
 # Check the error messages generated by tclsqlite
 #
 set r "sqlite_orig HANDLE ?FILENAME? ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN? ?-nofollow BOOLEAN? ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN?"
+ifcapable sharedschema {
+  append r " ?-shared-schema BOOLEAN?"
+}
 if {[sqlite3 -has-codec]} {
  append r " ?-key CODECKEY?"
 }
@@ -38,7 +38,7 @@
 #define SEL(e) ((e)->iLine = ((e)->rc ? (e)->iLine : __LINE__))

 /* Database functions */
-#define opendb(w,x,y,z)         (SEL(w), opendb_x(w,x,y,z))
+#define opendb(w,x,y,z,f)       (SEL(w), opendb_x(w,x,y,z,f))
 #define closedb(y,z)            (SEL(y), closedb_x(y,z))

 /* Functions to execute SQL */
@@ -545,11 +545,14 @@ static void opendb_x(
  Error *pErr,                    /* IN/OUT: Error code */
  Sqlite *pDb,                    /* OUT: Database handle */
  const char *zFile,              /* Database file name */
-  int bDelete                     /* True to delete db file before opening */
+  int bDelete,                    /* True to delete db file before opening */
+  int flags
 ){
  if( pErr->rc==SQLITE_OK ){
    int rc;
-    int flags = SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE | SQLITE_OPEN_URI;
+    if( flags==0 ){
+      flags = SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE | SQLITE_OPEN_URI;
+    }
    if( bDelete ) unlink(zFile);
    rc = sqlite3_open_v2(zFile, &pDb->db, flags, 0);
    if( rc ){
@@ -985,7 +988,7 @@ static char *walthread1_thread(int iTid, void *pArg){
  Sqlite db = {0};                /* SQLite database connection */
  int nIter = 0;                  /* Iterations so far */

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    const char *azSql[] = {
      "SELECT md5sum(x) FROM t1 WHERE rowid != (SELECT max(rowid) FROM t1)",
@@ -1024,7 +1027,7 @@ static char *walthread1_ckpt_thread(int iTid, void *pArg){
  Sqlite db = {0};                /* SQLite database connection */
  int nCkpt = 0;                  /* Checkpoints so far */

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    sqlite3_sleep(500);
    execsql(&err, &db, "PRAGMA wal_checkpoint");
@@ -1043,7 +1046,7 @@ static void walthread1(int nMs){
  Threadset threads = {0};        /* Test threads */
  int i;                          /* Iterator variable */

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db,
      "PRAGMA journal_mode = WAL;"
      "CREATE TABLE t1(x PRIMARY KEY);"
@@ -1076,7 +1079,7 @@ static char *walthread2_thread(int iTid, void *pArg){
    int journal_exists = 0;
    int wal_exists = 0;

-    opendb(&err, &db, "test.db", 0);
+    opendb(&err, &db, "test.db", 0, 0);

    sql_script(&err, &db, zJournal);
    clear_error(&err, SQLITE_BUSY);
@@ -1106,7 +1109,7 @@ static void walthread2(int nMs){
  Sqlite db = {0};
  Threadset threads = {0};

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, "CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE)");
  closedb(&err, &db);

@@ -1126,7 +1129,7 @@ static char *walthread3_thread(int iTid, void *pArg){
  i64 iNextWrite;                 /* Next value this thread will write */
  int iArg = PTR2INT(pArg);

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  sql_script(&err, &db, "PRAGMA wal_autocheckpoint = 10");

  iNextWrite = iArg+1;
@@ -1163,7 +1166,7 @@ static void walthread3(int nMs){
  Threadset threads = {0};
  int i;

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, 
      "PRAGMA journal_mode = WAL;"
      "CREATE TABLE t1(cnt PRIMARY KEY, sum1, sum2);"
@@ -1186,7 +1189,7 @@ static char *walthread4_reader_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    integrity_check(&err, &db);
  }
@@ -1201,7 +1204,7 @@ static char *walthread4_writer_thread(int iTid, void *pArg){
  Sqlite db = {0};                /* SQLite database connection */
  i64 iRow = 1;

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  sql_script(&err, &db, "PRAGMA wal_autocheckpoint = 15;");
  while( !timetostop(&err) ){
    execsql_i64(
@@ -1221,7 +1224,7 @@ static void walthread4(int nMs){
  Sqlite db = {0};
  Threadset threads = {0};

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, 
      "PRAGMA journal_mode = WAL;"
      "CREATE TABLE t1(a INTEGER PRIMARY KEY, b UNIQUE);"
@@ -1241,7 +1244,7 @@ static char *walthread5_thread(int iTid, void *pArg){
  Sqlite db = {0};                /* SQLite database connection */
  i64 nRow;

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  nRow = execsql_i64(&err, &db, "SELECT count(*) FROM t1");
  closedb(&err, &db);

@@ -1254,7 +1257,7 @@ static void walthread5(int nMs){
  Sqlite db = {0};
  Threadset threads = {0};

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, 
      "PRAGMA wal_autocheckpoint = 0;"
      "PRAGMA page_size = 1024;"
@@ -1345,7 +1348,7 @@ static void cgt_pager_1(int nMs){
  Error err = {0};
  Sqlite db = {0};

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db,
      "PRAGMA cache_size = 2000;"
      "PRAGMA page_size = 1024;"
@@ -1374,7 +1377,7 @@ static char *dynamic_triggers_1(int iTid, void *pArg){
  int nDrop = 0;
  int nCreate = 0;

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    int i;

@@ -1427,7 +1430,7 @@ static char *dynamic_triggers_2(int iTid, void *pArg){
  int nInsert = 0;
  int nDelete = 0;

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    do {
      iVal = (iVal+1)%100;
@@ -1452,7 +1455,7 @@ static void dynamic_triggers(int nMs){
  Sqlite db = {0};
  Threadset threads = {0};

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, 
      "PRAGMA page_size = 1024;"
      "PRAGMA journal_mode = WAL;"
@@ -1492,6 +1495,7 @@ static void dynamic_triggers(int nMs){
 #include "tt3_lookaside1.c"
 #include "tt3_vacuum.c"
 #include "tt3_stress.c"
+#include "tt3_reuseschema.c"
 #include "tt3_shared.c"

 int main(int argc, char **argv){
@@ -1517,6 +1521,7 @@ int main(int argc, char **argv){
    { vacuum1,             "vacuum1", 10000 },
    { stress1,             "stress1", 10000 },
    { stress2,             "stress2", 60000 },
+    { reuse_schema_1,      "reuse_schema_1", 20000 },
    { shared1,             "shared1", 10000 },
  };
  static char *substArgv[] = { 0, "*", 0 };
@@ -70,7 +70,7 @@ static char *checkpoint_starvation_reader(int iTid, void *pArg){
  Error err = {0};
  Sqlite db = {0};

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    i64 iCount1, iCount2;
    sql_script(&err, &db, "BEGIN");
@@ -96,7 +96,7 @@ static void checkpoint_starvation_main(int nMs, CheckpointStarvationCtx *p){
  int nInsert = 0;
  int i;

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, 
      "PRAGMA page_size = 1024;"
      "PRAGMA journal_mode = WAL;"
@@ -19,7 +19,7 @@ static char *create_drop_index_thread(int iTid, void *pArg){
  Sqlite db = {0};                /* SQLite database connection */

  while( !timetostop(&err) ){
-    opendb(&err, &db, "test.db", 0);
+    opendb(&err, &db, "test.db", 0, 0);

    sql_script(&err, &db, 
      "DROP INDEX IF EXISTS i1;"
@@ -51,7 +51,7 @@ static void create_drop_index_1(int nMs){
  Sqlite db = {0};
  Threadset threads = {0};

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, 
     "CREATE TABLE t11(a, b, c, d);"
     "WITH data(x) AS (SELECT 1 UNION ALL SELECT x+1 FROM data WHERE x<100) "
@@ -22,7 +22,7 @@ static char *lookaside1_thread_reader(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);

  while( !timetostop(&err) ){
    sqlite3_stmt *pStmt = 0;
@@ -47,7 +47,7 @@ static char *lookaside1_thread_writer(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);

  do{
    sql_script(&err, &db, 
@@ -68,7 +68,7 @@ static void lookaside1(int nMs){
  Sqlite db = {0};
  Threadset threads = {0};

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, 
     "CREATE TABLE t1(x PRIMARY KEY) WITHOUT ROWID;"
     "WITH data(x,y) AS ("
@@ -0,0 +1,73 @@
+/*
+** 2014 December 9
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+**     reuse_schema_1
+*/
+
+
+static char *reuse_schema_thread(int iTid, void *pArg){
+  Error err = {0};                /* Error code and message */
+  Sqlite db = {0};                /* SQLite database connection */
+  int iRep = 0;
+
+  while( !timetostop(&err) ){
+    int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_SHARED_SCHEMA;
+    opendb(&err, &db, "test.db", 0, f);
+
+    execsql_i64(&err, &db, "SELECT count(*) FROM t1");
+    sql_script(&err, &db, "ATTACH 'test.db2' AS aux");
+    execsql_i64(&err, &db, "SELECT count(*) FROM t1");
+
+    closedb(&err, &db);
+    iRep++;
+  }
+
+  print_and_free_err(&err);
+  return sqlite3_mprintf("%d", iRep);
+}
+
+static void reuse_schema_1(int nMs){
+  Error err = {0};
+  Sqlite db = {0};
+  Threadset threads = {0};
+
+  opendb(&err, &db, "test.db", 1, 0);
+  sql_script(&err, &db, 
+     "CREATE TABLE t1(a, b, c, d);"
+     "WITH data(x) AS (SELECT 1 UNION ALL SELECT x+1 FROM data WHERE x<100) "
+     "INSERT INTO t1 SELECT x,x,x,x FROM data;"
+  );
+  closedb(&err, &db);
+  opendb(&err, &db, "test.db2", 1, 0);
+  sql_script(&err, &db, 
+#ifdef SQLITE_ENABLE_FTS5
+     "CREATE VIRTUAL TABLE t2 USING fts5(a, b, c, d);"
+#else
+     "CREATE TABLE t2(a, b, c, d);"
+#endif
+     "WITH data(x) AS (SELECT 1 UNION ALL SELECT x+1 FROM data WHERE x<100) "
+     "INSERT INTO t2 SELECT x*2,x*2,x*2,x*2 FROM data;"
+  );
+  closedb(&err, &db);
+
+  setstoptime(&err, nMs);
+
+  launch_thread(&err, &threads, reuse_schema_thread, 0);
+  launch_thread(&err, &threads, reuse_schema_thread, 0);
+  launch_thread(&err, &threads, reuse_schema_thread, 0);
+  launch_thread(&err, &threads, reuse_schema_thread, 0);
+  launch_thread(&err, &threads, reuse_schema_thread, 0);
+
+  join_all_threads(&err, &threads);
+  sqlite3_enable_shared_cache(0);
+  print_and_free_err(&err);
+}
@@ -21,7 +21,7 @@ static char *stress_thread_1(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    sql_script(&err, &db, "CREATE TABLE IF NOT EXISTS t1(a PRIMARY KEY, b)");
    clear_error(&err, SQLITE_LOCKED);
@@ -40,7 +40,7 @@ static char *stress_thread_2(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  while( !timetostop(&err) ){
-    opendb(&err, &db, "test.db", 0);
+    opendb(&err, &db, "test.db", 0, 0);
    sql_script(&err, &db, "SELECT * FROM sqlite_schema;");
    clear_error(&err, SQLITE_LOCKED);
    closedb(&err, &db);
@@ -59,7 +59,7 @@ static char *stress_thread_3(int iTid, void *pArg){
  int i1 = 0;
  int i2 = 0;

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    sql_script(&err, &db, "SELECT * FROM t1 ORDER BY a;");
    i1++;
@@ -82,11 +82,11 @@ static char *stress_thread_4(int iTid, void *pArg){
  int i2 = 0;
  int iArg = PTR2INT(pArg);

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    if( iArg ){
      closedb(&err, &db);
-      opendb(&err, &db, "test.db", 0);
+      opendb(&err, &db, "test.db", 0, 0);
    }
    sql_script(&err, &db, 
        "WITH loop(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM loop LIMIT 200) "
@@ -113,12 +113,12 @@ static char *stress_thread_5(int iTid, void *pArg){
  int i1 = 0;
  int i2 = 0;

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    i64 i = (i1 % 4);
    if( iArg ){
      closedb(&err, &db);
-      opendb(&err, &db, "test.db", 0);
+      opendb(&err, &db, "test.db", 0, 0);
    }
    execsql(&err, &db, "DELETE FROM t1 WHERE (rowid % 4)==:i", &i);
    i1++;
@@ -265,7 +265,7 @@ static char *stress2_workload19(int iTid, void *pArg){
  Sqlite db = {0};                /* SQLite database connection */
  const char *zDb = (const char*)pArg;
  while( !timetostop(&err) ){
-    opendb(&err, &db, zDb, 0);
+    opendb(&err, &db, zDb, 0, 0);
    sql_script(&err, &db, "SELECT * FROM sqlite_schema;");
    clear_error(&err, SQLITE_LOCKED);
    closedb(&err, &db);
@@ -290,7 +290,7 @@ static char *stress2_thread_wrapper(int iTid, void *pArg){

  while( !timetostop(&err) ){
    int cnt;
-    opendb(&err, &db, pCtx->zDb, 0);
+    opendb(&err, &db, pCtx->zDb, 0, 0);
    for(cnt=0; err.rc==SQLITE_OK && cnt<STRESS2_TABCNT; cnt++){
      pCtx->xProc(&err, &db, i1);
      i2 += (err.rc==SQLITE_OK);
@@ -342,7 +342,7 @@ static void stress2(int nMs){
  Threadset threads = {0};

  /* To make sure the db file is empty before commencing */
-  opendb(&err, &db, zDb, 1);
+  opendb(&err, &db, zDb, 1, 0);
  sql_script(&err, &db, 
      "CREATE TABLE IF NOT EXISTS t0(x PRIMARY KEY, y, z);"
      "CREATE INDEX IF NOT EXISTS i0 ON t0(y);"
@@ -25,7 +25,7 @@ static char *vacuum1_thread_writer(int iTid, void *pArg){
  Sqlite db = {0};                /* SQLite database connection */
  i64 i = 0;

-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);
  while( !timetostop(&err) ){
    i++;

@@ -52,7 +52,7 @@ static char *vacuum1_thread_writer(int iTid, void *pArg){
 static char *vacuum1_thread_vacuumer(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
-  opendb(&err, &db, "test.db", 0);
+  opendb(&err, &db, "test.db", 0, 0);

  do{
    sql_script(&err, &db, "VACUUM");
@@ -69,7 +69,7 @@ static void vacuum1(int nMs){
  Sqlite db = {0};
  Threadset threads = {0};

-  opendb(&err, &db, "test.db", 1);
+  opendb(&err, &db, "test.db", 1, 0);
  sql_script(&err, &db, 
     "CREATE TABLE t1(x PRIMARY KEY, y BLOB);"
     "CREATE INDEX i1 ON t1(y);"
@@ -12,7 +12,7 @@

 # Flag meanings:
 set flagMeaning(NeedSchema) {Force schema load before running}
-set flagMeaning(ReadOnly)   {Read-only HEADER_VALUE}
+set flagMeaning(OneSchema)  {Only a single schema required}
 set flagMeaning(Result0)    {Acts as query when no argument}
 set flagMeaning(Result1)    {Acts as query when has one argument}
 set flagMeaning(SchemaReq)  {Schema required - "main" is default}
@@ -150,7 +150,7 @@ set pragma_def {
  ARG:  SQLITE_CellSizeCk

  NAME: default_cache_size
-  FLAG: NeedSchema Result0 SchemaReq NoColumns1
+  FLAG: NeedSchema Result0 SchemaReq NoColumns1 OneSchema
  COLS: cache_size
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)

@@ -163,12 +163,12 @@ set pragma_def {
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: page_count
-  FLAG: NeedSchema Result0 SchemaReq
+  FLAG: NeedSchema Result0 SchemaReq OneSchema
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: max_page_count
  TYPE: PAGE_COUNT
-  FLAG: NeedSchema Result0 SchemaReq
+  FLAG: NeedSchema Result0 SchemaReq OneSchema
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: locking_mode
@@ -176,7 +176,7 @@ set pragma_def {
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: journal_mode
-  FLAG: NeedSchema Result0 SchemaReq
+  FLAG: NeedSchema Result0 SchemaReq OneSchema
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: journal_size_limit
@@ -184,18 +184,18 @@ set pragma_def {
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: cache_size
-  FLAG: NeedSchema Result0 SchemaReq NoColumns1
+  FLAG: NeedSchema Result0 SchemaReq NoColumns1 OneSchema
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: mmap_size
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: auto_vacuum
-  FLAG: NeedSchema Result0 SchemaReq NoColumns1
+  FLAG: NeedSchema Result0 SchemaReq NoColumns1 OneSchema
  IF:   !defined(SQLITE_OMIT_AUTOVACUUM)

  NAME: incremental_vacuum
-  FLAG: NeedSchema NoColumns
+  FLAG: NeedSchema NoColumns OneSchema
  IF:   !defined(SQLITE_OMIT_AUTOVACUUM)

  NAME: temp_store
@@ -215,7 +215,7 @@ set pragma_def {
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS) && SQLITE_ENABLE_LOCKING_STYLE

  NAME: synchronous
-  FLAG: NeedSchema Result0 SchemaReq NoColumns1
+  FLAG: NeedSchema Result0 SchemaReq NoColumns1 OneSchema
  IF:   !defined(SQLITE_OMIT_PAGER_PRAGMAS)

  NAME: table_info
@@ -238,7 +238,7 @@ set pragma_def {
  IF:   !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)

  NAME: stats
-  FLAG: NeedSchema Result0 SchemaReq
+  FLAG: NeedSchema Result0 SchemaReq OneSchema
  COLS: tbl idx wdth hght flgs
  IF:   !defined(SQLITE_OMIT_SCHEMA_PRAGMAS) && defined(SQLITE_DEBUG)

@@ -290,7 +290,7 @@ set pragma_def {
  IF:   !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)

  NAME: foreign_key_list
-  FLAG: NeedSchema Result1 SchemaOpt
+  FLAG: NeedSchema Result1 SchemaOpt OneSchema
  COLS: id seq table from to on_update on_delete match
  IF:   !defined(SQLITE_OMIT_FOREIGN_KEY)

@@ -336,14 +336,14 @@ set pragma_def {

  NAME: data_version
  TYPE: HEADER_VALUE
-  ARG:  BTREE_DATA_VERSION
-  FLAG: ReadOnly Result0
+  ARG:  BTREE_DATA_VERSION|PRAGMA_HEADER_VALUE_READONLY
+  FLAG: Result0
  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: freelist_count
  TYPE: HEADER_VALUE
-  ARG:  BTREE_FREE_PAGE_COUNT
-  FLAG: ReadOnly Result0
+  ARG:  BTREE_FREE_PAGE_COUNT|PRAGMA_HEADER_VALUE_READONLY
+  FLAG: Result0
  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: application_id
@@ -357,7 +357,7 @@ set pragma_def {
  IF:   !defined(SQLITE_OMIT_COMPILEOPTION_DIAGS)

  NAME: wal_checkpoint
-  FLAG: NeedSchema
+  FLAG: NeedSchema OneSchema
  COLS: busy log checkpointed
  IF:   !defined(SQLITE_OMIT_WAL)

@@ -516,6 +516,12 @@ foreach f [lsort [array names allflags]] {
  set fv [expr {$fv*2}]
 }

+puts $fd "\n/* For PragTyp_HEADER_VALUE pragmas the Pragma.iArg value is set"
+puts $fd "** to the index of the header field to access (always 10 or less)."
+puts $fd "** Ored with HEADER_VALUE_READONLY if the field is read only. */"
+puts $fd "#define PRAGMA_HEADER_VALUE_READONLY 0x0100"
+puts $fd "#define PRAGMA_HEADER_VALUE_MASK 0x00FF\n"
+
 # Sort the column lists so that longer column lists occur first
 #
 proc colscmp {a b} {
@@ -1 +1 @@
 .39.0
 .39.4