Merge post-3.43.0 wal2 fixes into the wal2-3.43 sub-branch.

FossilOrigin-Name: f82b1a0bde3f836e25b704084674e3bee609ecea3dc9ef259218989bd1198482
Merge the latest 3.43.1 candidate patches into the wal2-3.43 branch.
2023-09-09 15:22:32 +00:00 · 2023-09-08 20:14:10 +00:00 · 2023-09-08 19:35:02 +00:00 · 2023-09-07 14:10:33 +00:00 · 2023-09-07 14:04:01 +00:00 · 2023-09-07 11:48:29 +00:00
60 changed files with 3976 additions and 997 deletions
@@ -425,6 +425,7 @@ TESTSRC += \
  $(TOP)/ext/expert/sqlite3expert.c \
  $(TOP)/ext/expert/test_expert.c \
  $(TOP)/ext/misc/amatch.c \
+  $(TOP)/ext/misc/bgckpt.c \
  $(TOP)/ext/misc/appendvfs.c \
  $(TOP)/ext/misc/basexx.c \
  $(TOP)/ext/misc/carray.c \
@@ -1563,6 +1563,7 @@ TESTEXT = \
  $(TOP)\ext\misc\amatch.c \
  $(TOP)\ext\misc\appendvfs.c \
  $(TOP)\ext\misc\basexx.c \
+  $(TOP)\ext\misc\bgckpt.c \
  $(TOP)\ext\misc\carray.c \
  $(TOP)\ext\misc\cksumvfs.c \
  $(TOP)\ext\misc\closure.c \
@@ -1 +1 @@
-3.43.0
+3.43.1
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for sqlite 3.43.0.
+# Generated by GNU Autoconf 2.69 for sqlite 3.43.1.
 #
 #
 # 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='3.43.0'
-PACKAGE_STRING='sqlite 3.43.0'
+PACKAGE_VERSION='3.43.1'
+PACKAGE_STRING='sqlite 3.43.1'
 PACKAGE_BUGREPORT=''
 PACKAGE_URL=''

@@ -1470,7 +1470,7 @@ 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 3.43.0 to adapt to many kinds of systems.
+\`configure' configures sqlite 3.43.1 to adapt to many kinds of systems.

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

@@ -1535,7 +1535,7 @@ fi

 if test -n "$ac_init_help"; then
  case $ac_init_help in
-     short | recursive ) echo "Configuration of sqlite 3.43.0:";;
+     short | recursive ) echo "Configuration of sqlite 3.43.1:";;
   esac
  cat <<\_ACEOF

@@ -1665,7 +1665,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
  cat <<\_ACEOF
-sqlite configure 3.43.0
+sqlite configure 3.43.1
 generated by GNU Autoconf 2.69

 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -2084,7 +2084,7 @@ 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 3.43.0, which was
+It was created by sqlite $as_me 3.43.1, which was
 generated by GNU Autoconf 2.69.  Invocation command line was

  $ $0 $@
@@ -12457,7 +12457,7 @@ cat >>$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 3.43.0, which was
+This file was extended by sqlite $as_me 3.43.1, which was
 generated by GNU Autoconf 2.69.  Invocation command line was

  CONFIG_FILES    = $CONFIG_FILES
@@ -12523,7 +12523,7 @@ _ACEOF
 cat >>$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 3.43.0
+sqlite config.status 3.43.1
 configured by $0, generated by GNU Autoconf 2.69,
  with options \\"\$ac_cs_config\\"

@@ -0,0 +1,98 @@
+
+Wal2 Mode Notes
+===============
+
+## Activating/Deactivating Wal2 Mode
+
+"Wal2" mode is very similar to "wal" mode. To change a database to wal2 mode,
+use the command:
+
+>
+     PRAGMA journal_mode = wal2;
+
+It is not possible to change a database directly from "wal" mode to "wal2"
+mode. Instead, it must first be changed to rollback mode. So, to change a wal
+mode database to wal2 mode, the following two commands may be used:
+
+>
+     PRAGMA journal_mode = delete;
+     PRAGMA journal_mode = wal2;
+
+A database in wal2 mode may only be accessed by versions of SQLite compiled
+from this branch. Attempting to use any other version of SQLite results in an
+SQLITE&#95;NOTADB error. A wal2 mode database may be changed back to rollback mode
+(making it accessible by all versions of SQLite) using:
+
+>
+     PRAGMA journal_mode = delete;
+
+## The Advantage of Wal2 Mode
+
+In legacy wal mode, when a writer writes data to the database, it doesn't
+modify the database file directly. Instead, it appends new data to the
+"&lt;database>-wal" file. Readers read data from both the original database
+file and the "&lt;database>-wal" file. At some point, data is copied from the
+"&lt;database>-wal" file into the database file, after which the wal file can
+be deleted or overwritten. Copying data from the wal file into the database
+file is called a "checkpoint", and may be done explictly (either by "PRAGMA
+wal&#95;checkpoint" or sqlite3&#95;wal&#95;checkpoint&#95;v2()), or
+automatically (by configuring "PRAGMA wal&#95;autocheckpoint" - this is the
+default).
+
+Checkpointers do not block writers, and writers do not block checkpointers.
+However, if a writer writes to the database while a checkpoint is ongoing,
+then the new data is appended to the end of the wal file. This means that,
+even following the checkpoint, the wal file cannot be overwritten or deleted,
+and so all subsequent transactions must also be appended to the wal file. The
+work of the checkpointer is not wasted - SQLite remembers which parts of the
+wal file have already been copied into the db file so that the next checkpoint
+does not have to do so again - but it does mean that the wal file may grow
+indefinitely if the checkpointer never gets a chance to finish without a
+writer appending to the wal file. There are also circumstances in which
+long-running readers may prevent a checkpointer from checkpointing the entire
+wal file - also causing the wal file to grow indefinitely in a busy system.
+
+Wal2 mode does not have this problem. In wal2 mode, wal files do not grow
+indefinitely even if the checkpointer never has a chance to finish
+uninterrupted.
+
+In wal2 mode, the system uses two wal files instead of one. The files are named
+"&lt;database>-wal" and "&lt;database>-wal2", where "&lt;database>" is of
+course the name of the database file. When data is written to the database, the
+writer begins by appending the new data to the first wal file. Once the first
+wal file has grown large enough, writers switch to appending data to the second
+wal file. At this point the first wal file can be checkpointed (after which it
+can be overwritten). Then, once the second wal file has grown large enough and
+the first wal file has been checkpointed, writers switch back to the first wal
+file. And so on.
+
+## Application Programming
+
+From the point of view of the user, the main differences between wal and 
+wal2 mode are to do with checkpointing:
+
+  * In wal mode, a checkpoint may be attempted at any time. In wal2 
+    mode, the checkpointer has to wait until writers have switched 
+    to the "other" wal file before a checkpoint can take place.
+
+  * In wal mode, the wal-hook (callback registered using
+    sqlite3&#95;wal&#95;hook()) is invoked after a transaction is committed
+    with the total number of pages in the wal file as an argument. In wal2
+    mode, the argument is either the total number of uncheckpointed pages in
+    both wal files, or - if the "other" wal file is empty or already
+    checkpointed - 0.
+
+Clients are recommended to use the same strategies for checkpointing wal2 mode
+databases as for wal databases - by registering a wal-hook using
+sqlite3&#95;wal&#95;hook() and attempting a checkpoint when the parameter
+exceeds a certain threshold.
+
+However, it should be noted that although the wal-hook is invoked after each
+transaction is committed to disk and database locks released, it is still
+invoked from within the sqlite3&#95;step() call used to execute the "COMMIT"
+command. In BEGIN CONCURRENT systems, where the "COMMIT" is often protected by
+an application mutex, this may reduce concurrency. In such systems, instead of
+executing a checkpoint from within the wal-hook, a thread might defer this
+action until after the application mutex has been released.
+
+
@@ -5218,7 +5218,7 @@ static u64 fts3ChecksumIndex(
  int rc;
  u64 cksum = 0;

-  assert( *pRc==SQLITE_OK );
+  if( *pRc ) return 0;

  memset(&filter, 0, sizeof(filter));
  memset(&csr, 0, sizeof(csr));
@@ -5198,80 +5198,79 @@ static void fts5DoSecureDelete(
      }
    }
  }else if( iStart==4 ){
-      int iPgno;
+    int iPgno;

-      assert_nc( pSeg->iLeafPgno>pSeg->iTermLeafPgno );
-      /* The entry being removed may be the only position list in
-      ** its doclist. */
-      for(iPgno=pSeg->iLeafPgno-1; iPgno>pSeg->iTermLeafPgno; iPgno-- ){
-        Fts5Data *pPg = fts5DataRead(p, FTS5_SEGMENT_ROWID(iSegid, iPgno));
-        int bEmpty = (pPg && pPg->nn==4);
-        fts5DataRelease(pPg);
-        if( bEmpty==0 ) break;
-      }
+    assert_nc( pSeg->iLeafPgno>pSeg->iTermLeafPgno );
+    /* The entry being removed may be the only position list in
+    ** its doclist. */
+    for(iPgno=pSeg->iLeafPgno-1; iPgno>pSeg->iTermLeafPgno; iPgno-- ){
+      Fts5Data *pPg = fts5DataRead(p, FTS5_SEGMENT_ROWID(iSegid, iPgno));
+      int bEmpty = (pPg && pPg->nn==4);
+      fts5DataRelease(pPg);
+      if( bEmpty==0 ) break;
+    }

-      if( iPgno==pSeg->iTermLeafPgno ){
-        i64 iId = FTS5_SEGMENT_ROWID(iSegid, pSeg->iTermLeafPgno);
-        Fts5Data *pTerm = fts5DataRead(p, iId);
-        if( pTerm && pTerm->szLeaf==pSeg->iTermLeafOffset ){
-          u8 *aTermIdx = &pTerm->p[pTerm->szLeaf];
-          int nTermIdx = pTerm->nn - pTerm->szLeaf;
-          int iTermIdx = 0;
-          int iTermOff = 0;
+    if( iPgno==pSeg->iTermLeafPgno ){
+      i64 iId = FTS5_SEGMENT_ROWID(iSegid, pSeg->iTermLeafPgno);
+      Fts5Data *pTerm = fts5DataRead(p, iId);
+      if( pTerm && pTerm->szLeaf==pSeg->iTermLeafOffset ){
+        u8 *aTermIdx = &pTerm->p[pTerm->szLeaf];
+        int nTermIdx = pTerm->nn - pTerm->szLeaf;
+        int iTermIdx = 0;
+        int iTermOff = 0;

-          while( 1 ){
-            u32 iVal = 0;
-            int nByte = fts5GetVarint32(&aTermIdx[iTermIdx], iVal);
-            iTermOff += iVal;
-            if( (iTermIdx+nByte)>=nTermIdx ) break;
-            iTermIdx += nByte;
-          }
-          nTermIdx = iTermIdx;
-
-          memmove(&pTerm->p[iTermOff], &pTerm->p[pTerm->szLeaf], nTermIdx);
-          fts5PutU16(&pTerm->p[2], iTermOff);
-
-          fts5DataWrite(p, iId, pTerm->p, iTermOff+nTermIdx);
-          if( nTermIdx==0 ){
-            fts5SecureDeleteIdxEntry(p, iSegid, pSeg->iTermLeafPgno);
-          }
+        while( 1 ){
+          u32 iVal = 0;
+          int nByte = fts5GetVarint32(&aTermIdx[iTermIdx], iVal);
+          iTermOff += iVal;
+          if( (iTermIdx+nByte)>=nTermIdx ) break;
+          iTermIdx += nByte;
        }
-        fts5DataRelease(pTerm);
+        nTermIdx = iTermIdx;
+
+        memmove(&pTerm->p[iTermOff], &pTerm->p[pTerm->szLeaf], nTermIdx);
+        fts5PutU16(&pTerm->p[2], iTermOff);
+
+        fts5DataWrite(p, iId, pTerm->p, iTermOff+nTermIdx);
+        if( nTermIdx==0 ){
+          fts5SecureDeleteIdxEntry(p, iSegid, pSeg->iTermLeafPgno);
+        }
+      }
+      fts5DataRelease(pTerm);
+    }
+  }
+
+  if( p->rc==SQLITE_OK ){
+    const int nMove = nPg - iNextOff;     /* Number of bytes to move */
+    int nShift = iNextOff - iOff;         /* Distance to move them */
+
+    int iPrevKeyOut = 0;
+    int iKeyIn = 0;
+
+    memmove(&aPg[iOff], &aPg[iNextOff], nMove);
+    iPgIdx -= nShift;
+    nPg = iPgIdx;
+    fts5PutU16(&aPg[2], iPgIdx);
+
+    for(iIdx=0; iIdx<nIdx; /* no-op */){
+      u32 iVal = 0;
+      iIdx += fts5GetVarint32(&aIdx[iIdx], iVal);
+      iKeyIn += iVal;
+      if( iKeyIn!=iDelKeyOff ){
+        int iKeyOut = (iKeyIn - (iKeyIn>iOff ? nShift : 0));
+        nPg += sqlite3Fts5PutVarint(&aPg[nPg], iKeyOut - iPrevKeyOut);
+        iPrevKeyOut = iKeyOut;
      }
    }

-    if( p->rc==SQLITE_OK ){
-      const int nMove = nPg - iNextOff;
-      int nShift = 0;
-
-      memmove(&aPg[iOff], &aPg[iNextOff], nMove);
-      iPgIdx -= (iNextOff - iOff);
-      nPg = iPgIdx;
-      fts5PutU16(&aPg[2], iPgIdx);
-
-      nShift = iNextOff - iOff;
-      for(iIdx=0, iKeyOff=0, iPrevKeyOff=0; iIdx<nIdx; /* no-op */){
-        u32 iVal = 0;
-        iIdx += fts5GetVarint32(&aIdx[iIdx], iVal);
-        iKeyOff += iVal;
-        if( iKeyOff!=iDelKeyOff ){
-          if( iKeyOff>iOff ){
-            iKeyOff -= nShift;
-            nShift = 0;
-          }
-          nPg += sqlite3Fts5PutVarint(&aPg[nPg], iKeyOff - iPrevKeyOff);
-          iPrevKeyOff = iKeyOff;
-        }
-      }
-
-      if( iPgIdx==nPg && nIdx>0 && pSeg->iLeafPgno!=1 ){
-        fts5SecureDeleteIdxEntry(p, iSegid, pSeg->iLeafPgno);
-      }
-
-      assert_nc( nPg>4 || fts5GetU16(aPg)==0 );
-      fts5DataWrite(p, FTS5_SEGMENT_ROWID(iSegid,pSeg->iLeafPgno), aPg,nPg);
+    if( iPgIdx==nPg && nIdx>0 && pSeg->iLeafPgno!=1 ){
+      fts5SecureDeleteIdxEntry(p, iSegid, pSeg->iLeafPgno);
    }
-    sqlite3_free(aIdx);
+
+    assert_nc( nPg>4 || fts5GetU16(aPg)==0 );
+    fts5DataWrite(p, FTS5_SEGMENT_ROWID(iSegid,pSeg->iLeafPgno), aPg, nPg);
+  }
+  sqlite3_free(aIdx);
 }

 /*
@@ -273,6 +273,19 @@ do_execsql_test 5.3 {
 do_execsql_test 5.4 { SELECT rowid FROM t1('abc'); } 2
 do_execsql_test 5.5 { SELECT rowid FROM t1('aa'); } 2

+#-------------------------------------------------------------------------
+reset_db
+
+do_execsql_test 6.0 {
+  CREATE VIRTUAL TABLE fts USING fts5(content);
+  INSERT INTO fts(fts, rank) VALUES ('secure-delete', 1);
+  INSERT INTO fts(rowid, content) VALUES
+    (3407, 'profile profile profile profile profile profile profile profile pull pulling pulling really');
+  DELETE FROM fts WHERE rowid IS 3407;
+  INSERT INTO fts(fts) VALUES ('integrity-check');
+}
+
+

 finish_test

@@ -0,0 +1,244 @@
+/*
+** 2017-10-11
+**
+** 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.
+**
+******************************************************************************
+**
+*/
+
+#if !defined(SQLITE_TEST) || defined(SQLITE_OS_UNIX)
+
+#include "sqlite3.h"
+#include <string.h>
+#include <pthread.h>
+
+/*
+** API declarations.
+*/
+typedef struct Checkpointer Checkpointer;
+int sqlite3_bgckpt_create(const char *zFilename, Checkpointer **pp);
+int sqlite3_bgckpt_checkpoint(Checkpointer *p, int bBlock);
+void sqlite3_bgckpt_destroy(Checkpointer *p);
+
+
+struct Checkpointer {
+  sqlite3 *db;                    /* Database handle */
+
+  pthread_t thread;               /* Background thread */
+  pthread_mutex_t mutex;
+  pthread_cond_t cond;
+
+  int rc;                         /* Error from "PRAGMA wal_checkpoint" */
+  int bCkpt;                      /* True if checkpoint requested */
+  int bExit;                      /* True if exit requested */
+};
+
+static void *bgckptThreadMain(void *pCtx){
+  int rc = SQLITE_OK;
+  Checkpointer *p = (Checkpointer*)pCtx;
+
+  while( rc==SQLITE_OK ){
+    int bExit;
+
+    pthread_mutex_lock(&p->mutex);
+    if( p->bCkpt==0 && p->bExit==0 ){
+      pthread_cond_wait(&p->cond, &p->mutex);
+    }
+    p->bCkpt = 0;
+    bExit = p->bExit;
+    pthread_mutex_unlock(&p->mutex);
+
+    if( bExit ) break;
+    rc = sqlite3_exec(p->db, "PRAGMA wal_checkpoint", 0, 0, 0);
+    if( rc==SQLITE_BUSY ){
+      rc = SQLITE_OK;
+    }
+  }
+
+  pthread_mutex_lock(&p->mutex);
+  p->rc = rc;
+  pthread_mutex_unlock(&p->mutex);
+  return 0;
+}
+
+void sqlite3_bgckpt_destroy(Checkpointer *p){
+  if( p ){
+    void *ret = 0;
+
+    /* Signal the background thread to exit */
+    pthread_mutex_lock(&p->mutex);
+    p->bExit = 1;
+    pthread_cond_broadcast(&p->cond);
+    pthread_mutex_unlock(&p->mutex);
+
+    pthread_join(p->thread, &ret);
+    sqlite3_close(p->db);
+    sqlite3_free(p);
+  }
+}
+
+
+int sqlite3_bgckpt_create(const char *zFilename, Checkpointer **pp){
+  Checkpointer *pNew = 0;
+  int rc;
+
+  pNew = (Checkpointer*)sqlite3_malloc(sizeof(Checkpointer));
+  if( pNew==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    memset(pNew, 0, sizeof(Checkpointer));
+    rc = sqlite3_open(zFilename, &pNew->db);
+  }
+
+  if( rc==SQLITE_OK ){
+    pthread_mutex_init(&pNew->mutex, 0);
+    pthread_cond_init(&pNew->cond, 0);
+    pthread_create(&pNew->thread, 0, bgckptThreadMain, (void*)pNew);
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_bgckpt_destroy(pNew);
+    pNew = 0;
+  }
+  *pp = pNew;
+  return rc;
+}
+
+int sqlite3_bgckpt_checkpoint(Checkpointer *p, int bBlock){
+  int rc;
+  pthread_mutex_lock(&p->mutex);
+  rc = p->rc;
+  if( rc==SQLITE_OK ){
+    p->bCkpt = 1;
+    pthread_cond_broadcast(&p->cond);
+  }
+  pthread_mutex_unlock(&p->mutex);
+  return rc;
+}
+
+#ifdef SQLITE_TEST
+
+#if defined(INCLUDE_SQLITE_TCL_H)
+#  include "sqlite_tcl.h"
+#else
+#  include "tcl.h"
+#  ifndef SQLITE_TCLAPI
+#    define SQLITE_TCLAPI
+#  endif
+#endif
+
+const char *sqlite3ErrName(int rc);
+
+static void SQLITE_TCLAPI bgckpt_del(void * clientData){
+  Checkpointer *pCkpt = (Checkpointer*)clientData;
+  sqlite3_bgckpt_destroy(pCkpt);
+}
+
+/*
+** Tclcmd: $ckpt SUBCMD ...
+*/
+static int SQLITE_TCLAPI bgckpt_obj_cmd(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  Checkpointer *pCkpt = (Checkpointer*)clientData;
+  const char *aCmd[] = { "checkpoint", "destroy", 0 };
+  int iCmd;
+
+  if( objc<2 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "SUBCMD ...");
+    return TCL_ERROR;
+  }
+
+  if( Tcl_GetIndexFromObj(interp, objv[1], aCmd, "sub-command", 0, &iCmd) ){
+    return TCL_ERROR;
+  }
+
+  switch( iCmd ){
+    case 0: {
+      int rc;
+      int bBlock = 0;
+
+      if( objc>3 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "?BLOCKING?");
+        return TCL_ERROR;
+      }
+      if( objc==3 && Tcl_GetBooleanFromObj(interp, objv[2], &bBlock) ){
+        return TCL_ERROR;
+      }
+
+      rc = sqlite3_bgckpt_checkpoint(pCkpt, bBlock);
+      if( rc!=SQLITE_OK ){
+        Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
+        return TCL_ERROR;
+      }
+      break;
+    }
+
+    case 1: {
+      Tcl_DeleteCommand(interp, Tcl_GetString(objv[0]));
+      break;
+    }
+  }
+
+  return TCL_OK;
+}
+
+/*
+** Tclcmd: bgckpt CMDNAME FILENAME
+*/
+static int SQLITE_TCLAPI bgckpt_cmd(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  const char *zCmd;
+  const char *zFilename;
+  int rc;
+  Checkpointer *pCkpt;
+
+  if( objc!=3 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "CMDNAME FILENAME");
+    return TCL_ERROR;
+  }
+  zCmd = Tcl_GetString(objv[1]);
+  zFilename = Tcl_GetString(objv[2]);
+
+  rc = sqlite3_bgckpt_create(zFilename, &pCkpt);
+  if( rc!=SQLITE_OK ){
+    Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
+    return TCL_ERROR;
+  }
+
+  Tcl_CreateObjCommand(interp, zCmd, bgckpt_obj_cmd, (void*)pCkpt, bgckpt_del);
+  Tcl_SetObjResult(interp, objv[1]);
+  return TCL_OK;
+}
+
+int Bgckpt_Init(Tcl_Interp *interp){
+  Tcl_CreateObjCommand(interp, "bgckpt", bgckpt_cmd, 0, 0);
+  return TCL_OK;
+}
+#endif   /* SQLITE_TEST */
+
+#else
+#if defined(INCLUDE_SQLITE_TCL_H)
+#  include "sqlite_tcl.h"
+#else
+#  include "tcl.h"
+#  ifndef SQLITE_TCLAPI
+#    define SQLITE_TCLAPI
+#  endif
+#endif
+int Bgckpt_Init(Tcl_Interp *interp){ return TCL_OK; }
+#endif
+
@@ -3236,15 +3236,19 @@ static int sessionReadRecord(
        }
      }
      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
-        sqlite3_int64 v = sessionGetI64(aVal);
-        if( eType==SQLITE_INTEGER ){
-          sqlite3VdbeMemSetInt64(apOut[i], v);
+        if( (pIn->nData-pIn->iNext)<8 ){
+          rc = SQLITE_CORRUPT_BKPT;
        }else{
-          double d;
-          memcpy(&d, &v, 8);
-          sqlite3VdbeMemSetDouble(apOut[i], d);
+          sqlite3_int64 v = sessionGetI64(aVal);
+          if( eType==SQLITE_INTEGER ){
+            sqlite3VdbeMemSetInt64(apOut[i], v);
+          }else{
+            double d;
+            memcpy(&d, &v, 8);
+            sqlite3VdbeMemSetDouble(apOut[i], d);
+          }
+          pIn->iNext += 8;
        }
-        pIn->iNext += 8;
      }
    }
  }
@@ -1,10 +1,7 @@
+_fiddle_exec
+_fiddle_interrupt
+_fiddle_experiment
+_fiddle_the_db
 _fiddle_db_arg
 _fiddle_db_filename
-_fiddle_exec
-_fiddle_experiment
-_fiddle_interrupt
-_fiddle_main
 _fiddle_reset_db
-_fiddle_db_handle
-_fiddle_db_vfs
-_fiddle_export_db
@@ -845,11 +845,11 @@ sqlite3-worker1-bundler-friendly.js := $(dir.dout)/sqlite3-worker1-bundler-frien
 sqlite3-worker1-promiser-bundler-friendly.js := $(dir.dout)/sqlite3-worker1-promiser-bundler-friendly.js
 $(eval $(call C-PP.FILTER,$(sqlite3-worker1.js.in),$(sqlite3-worker1.js)))
 $(eval $(call C-PP.FILTER,$(sqlite3-worker1.js.in),$(sqlite3-worker1-bundler-friendly.js),\
-    $(c-pp.D.bundler-friendly)))
+    $(c-pp.D.sqlite3-bundler-friendly)))
 $(eval $(call C-PP.FILTER,$(sqlite3-worker1-promiser.js.in),$(sqlite3-worker1-promiser.js)))
 $(eval $(call C-PP.FILTER,$(sqlite3-worker1-promiser.js.in),\
    $(sqlite3-worker1-promiser-bundler-friendly.js),\
-    $(c-pp.D.bundler-friendly)))
+    $(c-pp.D.sqlite3-bundler-friendly)))
 $(sqlite3-bundler-friendly.mjs): $(sqlite3-worker1-bundler-friendly.js) \
    $(sqlite3-worker1-promiser-bundler-friendly.js)
 $(sqlite3.js) $(sqlite3.mjs): $(sqlite3-worker1.js) $(sqlite3-worker1-promiser.js)
@@ -1,8 +1,3 @@
-_malloc
-_free
-_realloc
-_sqlite3_aggregate_context
-_sqlite3_auto_extension
 _sqlite3_bind_blob
 _sqlite3_bind_double
 _sqlite3_bind_int
@@ -10,16 +5,11 @@ _sqlite3_bind_int64
 _sqlite3_bind_null
 _sqlite3_bind_parameter_count
 _sqlite3_bind_parameter_index
-_sqlite3_bind_pointer
 _sqlite3_bind_text
-_sqlite3_busy_handler
-_sqlite3_busy_timeout
-_sqlite3_cancel_auto_extension
 _sqlite3_changes
 _sqlite3_changes64
 _sqlite3_clear_bindings
 _sqlite3_close_v2
-_sqlite3_collation_needed
 _sqlite3_column_blob
 _sqlite3_column_bytes
 _sqlite3_column_count
@@ -30,28 +20,12 @@ _sqlite3_column_int64
 _sqlite3_column_name
 _sqlite3_column_text
 _sqlite3_column_type
-_sqlite3_column_value
-_sqlite3_commit_hook
 _sqlite3_compileoption_get
 _sqlite3_compileoption_used
-_sqlite3_complete
-_sqlite3_context_db_handle
-_sqlite3_create_collation
-_sqlite3_create_collation_v2
-_sqlite3_create_function
 _sqlite3_create_function_v2
-_sqlite3_create_module
-_sqlite3_create_module_v2
-_sqlite3_create_window_function
 _sqlite3_data_count
 _sqlite3_db_filename
-_sqlite3_db_handle
 _sqlite3_db_name
-_sqlite3_db_status
-_sqlite3_declare_vtab
-_sqlite3_deserialize
-_sqlite3_drop_modules
-_sqlite3_errcode
 _sqlite3_errmsg
 _sqlite3_error_offset
 _sqlite3_errstr
@@ -59,38 +33,16 @@ _sqlite3_exec
 _sqlite3_expanded_sql
 _sqlite3_extended_errcode
 _sqlite3_extended_result_codes
-_sqlite3_file_control
 _sqlite3_finalize
-_sqlite3_free
-_sqlite3_get_auxdata
 _sqlite3_initialize
-_sqlite3_keyword_count
-_sqlite3_keyword_name
-_sqlite3_keyword_check
-_sqlite3_last_insert_rowid
+_sqlite3_interrupt
 _sqlite3_libversion
 _sqlite3_libversion_number
-_sqlite3_limit
-_sqlite3_malloc
-_sqlite3_malloc64
-_sqlite3_msize
 _sqlite3_open
 _sqlite3_open_v2
-_sqlite3_overload_function
 _sqlite3_prepare_v2
 _sqlite3_prepare_v3
-_sqlite3_preupdate_blobwrite
-_sqlite3_preupdate_count
-_sqlite3_preupdate_depth
-_sqlite3_preupdate_hook
-_sqlite3_preupdate_new
-_sqlite3_preupdate_old
-_sqlite3_progress_handler
-_sqlite3_randomness
-_sqlite3_realloc
-_sqlite3_realloc64
 _sqlite3_reset
-_sqlite3_reset_auto_extension
 _sqlite3_result_blob
 _sqlite3_result_double
 _sqlite3_result_error
@@ -98,106 +50,23 @@ _sqlite3_result_error_code
 _sqlite3_result_error_nomem
 _sqlite3_result_error_toobig
 _sqlite3_result_int
-_sqlite3_result_int64
 _sqlite3_result_null
-_sqlite3_result_pointer
-_sqlite3_result_subtype
 _sqlite3_result_text
-_sqlite3_result_zeroblob
-_sqlite3_result_zeroblob64
-_sqlite3_rollback_hook
-_sqlite3_serialize
-_sqlite3_set_authorizer
-_sqlite3_set_auxdata
-_sqlite3_set_last_insert_rowid
-_sqlite3_shutdown
 _sqlite3_sourceid
 _sqlite3_sql
-_sqlite3_status
-_sqlite3_status64
 _sqlite3_step
-_sqlite3_stmt_isexplain
-_sqlite3_stmt_readonly
-_sqlite3_stmt_status
 _sqlite3_strglob
-_sqlite3_stricmp
 _sqlite3_strlike
-_sqlite3_strnicmp
-_sqlite3_table_column_metadata
 _sqlite3_total_changes
 _sqlite3_total_changes64
-_sqlite3_trace_v2
-_sqlite3_txn_state
-_sqlite3_update_hook
-_sqlite3_uri_boolean
-_sqlite3_uri_int64
-_sqlite3_uri_key
-_sqlite3_uri_parameter
-_sqlite3_user_data
 _sqlite3_value_blob
 _sqlite3_value_bytes
 _sqlite3_value_double
-_sqlite3_value_dup
-_sqlite3_value_free
-_sqlite3_value_frombind
-_sqlite3_value_int
-_sqlite3_value_int64
-_sqlite3_value_nochange
-_sqlite3_value_numeric_type
-_sqlite3_value_pointer
-_sqlite3_value_subtype
 _sqlite3_value_text
 _sqlite3_value_type
 _sqlite3_vfs_find
 _sqlite3_vfs_register
-_sqlite3_vfs_unregister
-_sqlite3_vtab_collation
-_sqlite3_vtab_distinct
-_sqlite3_vtab_in
-_sqlite3_vtab_in_first
-_sqlite3_vtab_in_next
-_sqlite3_vtab_nochange
-_sqlite3_vtab_on_conflict
-_sqlite3_vtab_rhs_value
-_sqlite3changegroup_add
-_sqlite3changegroup_add_strm
-_sqlite3changegroup_delete
-_sqlite3changegroup_new
-_sqlite3changegroup_output
-_sqlite3changegroup_output_strm
-_sqlite3changeset_apply
-_sqlite3changeset_apply_strm
-_sqlite3changeset_apply_v2
-_sqlite3changeset_apply_v2_strm
-_sqlite3changeset_concat
-_sqlite3changeset_concat_strm
-_sqlite3changeset_conflict
-_sqlite3changeset_finalize
-_sqlite3changeset_fk_conflicts
-_sqlite3changeset_invert
-_sqlite3changeset_invert_strm
-_sqlite3changeset_new
-_sqlite3changeset_next
-_sqlite3changeset_old
-_sqlite3changeset_op
-_sqlite3changeset_pk
-_sqlite3changeset_start
-_sqlite3changeset_start_strm
-_sqlite3changeset_start_v2
-_sqlite3changeset_start_v2_strm
-_sqlite3session_attach
-_sqlite3session_changeset
-_sqlite3session_changeset_size
-_sqlite3session_changeset_strm
-_sqlite3session_config
-_sqlite3session_create
-_sqlite3session_delete
-_sqlite3session_diff
-_sqlite3session_enable
-_sqlite3session_indirect
-_sqlite3session_isempty
-_sqlite3session_memory_used
-_sqlite3session_object_config
-_sqlite3session_patchset
-_sqlite3session_patchset_strm
-_sqlite3session_table_filter
+_sqlite3_wasm_db_error
+_sqlite3_wasm_enum_json
+_malloc
+_free
@@ -890,6 +890,8 @@ globalThis.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
        this.setAssociatedPath(sah, '', 0);
        toss("Expected to write "+n+" bytes but wrote "+nWrote+".");
      }else{
+        sah.write(new Uint8Array([1,1]), {at: HEADER_OFFSET_DATA+18}
+                  /* force db out of WAL mode */);
        this.setAssociatedPath(sah, name, capi.SQLITE_OPEN_MAIN_DB);
      }
    }
@@ -1192,16 +1192,25 @@ const installOpfsVfs = function callee(options){
          toss("Input does not contain an SQLite database header.");
        }
      }
+      let sah;
      const [hDir, fnamePart] = await opfsUtil.getDirForFilename(filename, true);
-      const hFile = await hDir.getFileHandle(fnamePart, {create:true});
-      const sah = await hFile.createSyncAccessHandle();
-      sah.truncate(0);
-      const nWrote = sah.write(bytes, {at: 0});
-      sah.close();
-      if(nWrote != n){
-        toss("Expected to write "+n+" bytes but wrote "+nWrote+".");
+      try {
+        const hFile = await hDir.getFileHandle(fnamePart, {create:true});
+        sah = await hFile.createSyncAccessHandle();
+        sah.truncate(0);
+        const nWrote = sah.write(bytes, {at: 0});
+        if(nWrote != n){
+          toss("Expected to write "+n+" bytes but wrote "+nWrote+".");
+        }
+        sah.write(new Uint8Array([1,1]), {at: 18}) /* force db out of WAL mode */;
+        return nWrote;
+      }catch(e){
+        if( sah ){ await sah.close(); sah = undefined; }
+        await hDir.removeEntry( fnamePart ).catch(()=>{});
+        throw e;
+      }finally{
+        if( sah ) await sah.close();
      }
-      return nWrote;
    };

    if(sqlite3.oo1){
@@ -114,7 +114,7 @@
   by all client code except that which tests this API. The `row`
   property contains the row result in the form implied by the
   `rowMode` option (defaulting to `'array'`). The `rowNumber` is a
-   1-based integer value incremented by 1 on each call into the
+   1-based integer value incremented by 1 on each call into th 
   callback.

   At the end of the result set, the same event is fired with
@@ -122,17 +122,8 @@
   the end of the result set has been reached. Note that the rows
   arrive via worker-posted messages, with all the implications
   of that.
-
-   Notable shortcomings:
-
-   - This API was not designed with ES6 modules in mind. Neither Firefox
-     nor Safari support, as of March 2023, the {type:"module"} flag to the
-     Worker constructor, so that particular usage is not something we're going
-     to target for the time being:
-
-     https://developer.mozilla.org/en-US/docs/Web/API/Worker/Worker
 */
-globalThis.sqlite3Worker1Promiser = function callee(config = callee.defaultConfig){
+self.sqlite3Worker1Promiser = function callee(config = callee.defaultConfig){
  // Inspired by: https://stackoverflow.com/a/52439530
  if(1===arguments.length && 'function'===typeof arguments[0]){
    const f = config;
@@ -169,7 +160,7 @@ globalThis.sqlite3Worker1Promiser = function callee(config = callee.defaultConfi
      if(msgHandler && msgHandler.onrow){
        msgHandler.onrow(ev);
        return;
-      }
+      }        
      if(config.onunhandled) config.onunhandled(arguments[0]);
      else err("sqlite3Worker1Promiser() unhandled worker message:",ev);
      return;
@@ -196,9 +187,10 @@ globalThis.sqlite3Worker1Promiser = function callee(config = callee.defaultConfi
    if(1===arguments.length){
      msg = arguments[0];
    }else if(2===arguments.length){
-      msg = Object.create(null);
-      msg.type = arguments[0];
-      msg.args = arguments[1];
+      msg = {
+        type: arguments[0],
+        args: arguments[1]
+      };
    }else{
      toss("Invalid arugments for sqlite3Worker1Promiser()-created factory.");
    }
@@ -244,31 +236,28 @@ globalThis.sqlite3Worker1Promiser = function callee(config = callee.defaultConfi
    return p;
  };
 }/*sqlite3Worker1Promiser()*/;
-globalThis.sqlite3Worker1Promiser.defaultConfig = {
+self.sqlite3Worker1Promiser.defaultConfig = {
  worker: function(){
 //#if target=es6-bundler-friendly
-    return new Worker("sqlite3-worker1-bundler-friendly.mjs",{
-      type: 'module' /* Noting that neither Firefox nor Safari suppor this,
-                        as of this writing. */
-    });
+    return new Worker("sqlite3-worker1.js");
 //#else
    let theJs = "sqlite3-worker1.js";
    if(this.currentScript){
      const src = this.currentScript.src.split('/');
      src.pop();
      theJs = src.join('/')+'/' + theJs;
-      //sqlite3.config.warn("promiser currentScript, theJs =",this.currentScript,theJs);
-    }else if(globalThis.location){
-      //sqlite3.config.warn("promiser globalThis.location =",globalThis.location);
-      const urlParams = new URL(globalThis.location.href).searchParams;
+      //console.warn("promiser currentScript, theJs =",this.currentScript,theJs);
+    }else{
+      //console.warn("promiser self.location =",self.location);
+      const urlParams = new URL(self.location.href).searchParams;
      if(urlParams.has('sqlite3.dir')){
        theJs = urlParams.get('sqlite3.dir') + '/' + theJs;
      }
    }
-    return new Worker(theJs + globalThis.location.search);
+    return new Worker(theJs + self.location.search);
 //#endif
  }.bind({
-    currentScript: globalThis?.document?.currentScript
+    currentScript: self?.document?.currentScript
  }),
  onerror: (...args)=>console.error('worker1 promiser error',...args)
 };
@@ -273,6 +273,11 @@
        </fieldset>
      </div>
    </div> <!-- #view-split -->
+    <!-- Maintenance notes:
+
+        ... TODO... currently being refactored...
+
+    -->
    <script src="fiddle.js"></script>
  </body>
 </html>
@@ -344,6 +344,7 @@ TESTSRC += \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/appendvfs.c \
  $(TOP)/ext/misc/basexx.c \
+  $(TOP)/ext/misc/bgckpt.c \
  $(TOP)/ext/misc/carray.c \
  $(TOP)/ext/misc/cksumvfs.c \
  $(TOP)/ext/misc/closure.c \
@@ -1,13 +1,13 @@
-C Version\s3.43.0
-D 2023-08-24T12:36:59.632
+C Merge\spost-3.43.0\swal2\sfixes\sinto\sthe\swal2-3.43\ssub-branch.
+D 2023-09-09T15:22:32.682
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
-F Makefile.in 1e9105ffed727b1557ce59f0941c5d271e276ec00bc9823f03d77a89e131b918
+F Makefile.in 8b41ee9426d750c0170cef0218e7c2028907b67abc08ebe51f1968b06d79d4db
 F Makefile.linux-gcc f3842a0b1efbfbb74ac0ef60e56b301836d05b4d867d014f714fa750048f1ab6
-F Makefile.msc 26c2d196391a285c279adb10fd6001774d9b243af94b700b681e4a49cd476684
+F Makefile.msc 01eac287493d2ea7b0ced738dcf19a2234c60195d39e1c86f2b0fa20c9d7d14e
 F README.md 963d30019abf0cc06b263cd2824bce022893f3f93a531758f6f04ff2194a16a8
-F VERSION c6366dc72582d3144ce87b013cc35fe48d62f6d07d5be0c9716ea33c862144aa
+F VERSION 536457fc6444f62ad9e5082a82e4e190f7ba3f4d903a63b835835230f7a8f853
 F aclocal.m4 a5c22d164aff7ed549d53a90fa56d56955281f50
 F art/sqlite370.eps aa97a671332b432a54e1d74ff5e8775be34200c2
 F art/sqlite370.ico af56c1d00fee7cd4753e8631ed60703ed0fc6e90
@@ -33,7 +33,7 @@ F autoconf/tea/win/nmakehlp.c b01f822eabbe1ed2b64e70882d97d48402b42d2689a1ea0034
 F autoconf/tea/win/rules.vc c511f222b80064096b705dbeb97060ee1d6b6d63
 F config.guess 883205ddf25b46f10c181818bf42c09da9888884af96f79e1719264345053bd6
 F config.sub c2d0260f17f3e4bc0b6808fccf1b291cb5e9126c14fc5890efc77b9fd0175559
-F configure 9dc3300339f4d6b3c3b108de60cc6ae6b3c547e25c7e6df280b4775db4de3a1b x
+F configure 8f9bd15e5edda5730621f630be36c7273a2ad7dfa080bfdcb7abb8f063967c52 x
 F configure.ac 4654d32ac0a0d0b48f1e1e79bdc3d777b723cf2f63c33eb1d7c4ed8b435938e8
 F contrib/sqlitecon.tcl 210a913ad63f9f991070821e599d600bd913e0ad
 F doc/F2FS.txt c1d4a0ae9711cfe0e1d8b019d154f1c29e0d3abfe820787ba1e9ed7691160fcd
@@ -45,6 +45,7 @@ F doc/trusted-schema.md 33625008620e879c7bcfbbfa079587612c434fa094d338b08242288d
 F doc/vdbesort-memory.md 4da2639c14cd24a31e0af694b1a8dd37eaf277aff3867e9a8cc14046bc49df56
 F doc/vfs-shm.txt e101f27ea02a8387ce46a05be2b1a902a021d37a
 F doc/wal-lock.md 781726aaba20bafeceb7ba9f91d5c98c6731691b30c954e37cf0b49a053d461d
+F doc/wal2.md a807405a05e19a4945c5905a9ffa0fe45b8560dd7572461192501f565c19cdb5
 F ext/README.md fd5f78013b0a2bc6f0067afb19e6ad040e89a10179b4f6f03eee58fac5f169bd
 F ext/async/README.txt e12275968f6fde133a80e04387d0e839b0c51f91
 F ext/async/sqlite3async.c 6f247666b495c477628dd19364d279c78ea48cd90c72d9f9b98ad1aff3294f94
@@ -77,7 +78,7 @@ F ext/fts3/fts3_tokenizer.h 64c6ef6c5272c51ebe60fc607a896e84288fcbc3
 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 d28d9ef383ef848a7b77df4b9964abcc90d67a2b584120c0ad465972dce416e6
+F ext/fts3/fts3_write.c b28f4cde90ed560245ecb76a882b45aa62da16ff6f61e9884eae5c7c5eff16ea
 F ext/fts3/fts3speed.tcl b54caf6a18d38174f1a6e84219950d85e98bb1e9
 F ext/fts3/tool/fts3cov.sh c331d006359456cf6f8f953e37f2b9c7d568f3863f00bb5f7eb87fea4ac01b73
 F ext/fts3/tool/fts3view.c 413c346399159df81f86c4928b7c4a455caab73bfbc8cd68f950f632e5751674
@@ -93,7 +94,7 @@ F ext/fts5/fts5_buffer.c 3001fbabb585d6de52947b44b455235072b741038391f830d6b7292
 F ext/fts5/fts5_config.c 054359543566cbff1ba65a188330660a5457299513ac71c53b3a07d934c7b081
 F ext/fts5/fts5_expr.c bd3b81ce669c4104e34ffe66570af1999a317b142c15fccb112de9fb0caa57a6
 F ext/fts5/fts5_hash.c 65e7707bc8774706574346d18c20218facf87de3599b995963c3e6d6809f203d
-F ext/fts5/fts5_index.c b484322421cbb421d22bb2cd304001b80596d671cd626367c8c806b889de4b42
+F ext/fts5/fts5_index.c bb405cb68fc5306107133d29ea8f86337bba360fe1c6029043d16a3026a26767
 F ext/fts5/fts5_main.c 7070031993ba5b5d89b13206ec4ef624895f2f7c0ec72725913d301e4d382445
 F ext/fts5/fts5_storage.c 3c9b41fce41b6410f2e8f82eb035c6a29b2560483f773e6dc98cf3cb2e4ddbb5
 F ext/fts5/fts5_tcl.c b1445cbe69908c411df8084a10b2485500ac70a9c747cdc8cda175a3da59d8ae
@@ -197,7 +198,7 @@ F ext/fts5/test/fts5rebuild.test 55d6f17715cddbf825680dd6551efbc72ed916d8cf1cde4
 F ext/fts5/test/fts5restart.test 835ecc8f449e3919f72509ab58056d0cedca40d1fe04108ccf8ac4c2ba41f415
 F ext/fts5/test/fts5rowid.test b8790ec170a8dc1942a15aef3db926a5f3061b1ff171013003d8297203a20ad6
 F ext/fts5/test/fts5savepoint.test fc02929f238d02a22df4172625704e029f7c1e0e92e332d654375690f8e6e43f
-F ext/fts5/test/fts5secure.test 214a561519d1b1817f146efd1057e2a97cc896e75c2accc77157d874154bda64
+F ext/fts5/test/fts5secure.test 833f987e6902a9ab20fabbaa7ca0662c6187fa368cbc7a8082fdf2bf22ee0304
 F ext/fts5/test/fts5secure2.test 2e961d7eef939f294c56b5d895cac7f1c3a60b934ee2cfd5e5e620bdf1ba6bbc
 F ext/fts5/test/fts5secure3.test c7e1080a6912f2a3ac68f2e05b88b72a99de38543509b2bbf427cac5c9c1c610
 F ext/fts5/test/fts5secure4.test 0d10a80590c07891478700af7793b232962042677432b9846cf7fc8337b67c97
@@ -324,6 +325,7 @@ F ext/misc/appendvfs.c 9642c7a194a2a25dca7ad3e36af24a0a46d7702168c4ad7e59c9f9b0e
 F ext/misc/base64.c a71b131e50300c654a66c469a25b62874481f3d1cb3beb56aca9a68edd812e0d
 F ext/misc/base85.c 073054111988db593ef5fdb87ab8c459df1ea0c3aaaddf0f5bfa3d72b7e6280a
 F ext/misc/basexx.c 89ad6b76558efbceb627afd5e2ef1d84b2e96d9aaf9b7ecb20e3d00b51be6fcf
+F ext/misc/bgckpt.c 49ae19aa03e6da393db5d17da256374d4c4d36889fdd89d6e4bc93aca2b752e6
 F ext/misc/blobio.c a867c4c4617f6ec223a307ebfe0eabb45e0992f74dd47722b96f3e631c0edb2a
 F ext/misc/btreeinfo.c d28ce349b40054eaa9473e835837bad7a71deec33ba13e39f963d50933bfa0f9
 F ext/misc/carray.c 0ba03f1e6647785d4e05b51be567f5652f06941314ff9d3d3763900aa353b6b5
@@ -522,17 +524,17 @@ F ext/session/sessionrowid.test 85187c2f1b38861a5844868126f69f9ec62223a03449a98a
 F ext/session/sessionsize.test 8fcf4685993c3dbaa46a24183940ab9f5aa9ed0d23e5fb63bfffbdb56134b795
 F ext/session/sessionstat1.test b039e38e2ba83767b464baf39b297cc0b1cc6f3292255cb467ea7e12d0d0280c
 F ext/session/sessionwor.test 6fd9a2256442cebde5b2284936ae9e0d54bde692d0f5fd009ecef8511f4cf3fc
-F ext/session/sqlite3session.c 1971b61ca45babf0d9e4bb669a65b0903135e9828af2fcd4f0c8f1b7acf36b6f
+F ext/session/sqlite3session.c 0fe9107318140cefa1b50f2e1e0f330ab359022599e5976820db349f33efae11
 F ext/session/sqlite3session.h 653e9d49c4edae231df8a4c8d69c2145195aedb32462d4b44229dbee7d2680fb
 F ext/session/test_session.c 5285482f83cd92b4c1fe12fcf88210566a18312f4f2aa110f6399dae46aeccbb
 F ext/userauth/sqlite3userauth.h 7f3ea8c4686db8e40b0a0e7a8e0b00fac13aa7a3
 F ext/userauth/user-auth.txt e6641021a9210364665fe625d067617d03f27b04
 F ext/userauth/userauth.c 7f00cded7dcaa5d47f54539b290a43d2e59f4b1eb5f447545fa865f002fc80cb
-F ext/wasm/EXPORTED_FUNCTIONS.fiddle.in 27450c8b8c70875a260aca55435ec927068b34cef801a96205adb81bdcefc65c
-F ext/wasm/GNUmakefile d02f3c8798b754f68b1f6b422ccff894a10bf352fc9c4eb8945baeace1acac28
+F ext/wasm/EXPORTED_FUNCTIONS.fiddle 7fb73f7150ab79d83bb45a67d257553c905c78cd3d693101699243f36c5ae6c3
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 F ext/wasm/README-dist.txt 6382cb9548076fca472fb3330bbdba3a55c1ea0b180ff9253f084f07ff383576
 F ext/wasm/README.md a8a2962c3aebdf8d2104a9102e336c5554e78fc6072746e5daf9c61514e7d193
-F ext/wasm/api/EXPORTED_FUNCTIONS.sqlite3-api d6a5078f48a5301ed17b9a30331075d9b2506e1360c1f0dee0c7816c10acd9ab
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 F ext/wasm/api/EXPORTED_FUNCTIONS.sqlite3-see fb29e62082a658f0d81102488414d422c393c4b20cc2f685b216bc566237957b
 F ext/wasm/api/EXPORTED_RUNTIME_METHODS.sqlite3-api 1ec3c73e7d66e95529c3c64ac3de2470b0e9e7fbf7a5b41261c367cf4f1b7287
 F ext/wasm/api/README.md 5eb44fa02e9c693a1884a3692428647894b0380b24bca120866b7a24c8786134
@@ -549,10 +551,10 @@ F ext/wasm/api/sqlite3-api-worker1.js 9f32af64df1a031071912eea7a201557fe39b17386
 F ext/wasm/api/sqlite3-license-version-header.js 0c807a421f0187e778dc1078f10d2994b915123c1223fe752b60afdcd1263f89
 F ext/wasm/api/sqlite3-opfs-async-proxy.js 8cf8a897726f14071fae6be6648125162b256dfb4f96555b865dbb7a6b65e379
 F ext/wasm/api/sqlite3-v-helper.js 7daa0eab0a513a25b05e9abae7b5beaaa39209b3ed12f86aeae9ef8d2719ed25
-F ext/wasm/api/sqlite3-vfs-opfs-sahpool.c-pp.js abb69b5e008961026bf5ff433d7116cb046359af92a5daf73208af2e7ac80ae7
-F ext/wasm/api/sqlite3-vfs-opfs.c-pp.js e04fc2fda6a0200ef80efdbb4ddfa0254453558adb17ec3a230f93d2bf1d711c
+F ext/wasm/api/sqlite3-vfs-opfs-sahpool.c-pp.js c7caf5ccd85d6e92bee4285871d51bc0e3e635b3e2d76f50515f5482a0ec0239
+F ext/wasm/api/sqlite3-vfs-opfs.c-pp.js cf0a2a182d16e71c5ccb1a870bfdba0d0da5e2fe5542907b036e92b3db5982c3
 F ext/wasm/api/sqlite3-wasm.c d4d4c2b349b43b7b861e6d2994299630fb79e07573ea6b61e28e8071b7d16b61
-F ext/wasm/api/sqlite3-worker1-promiser.c-pp.js bc06df0d599e625bde6a10a394e326dc68da9ff07fa5404354580f81566e591f
+F ext/wasm/api/sqlite3-worker1-promiser.c-pp.js f10c3ecd9df06f6320073c2ce230a7ed7c56034d8b88c1e57095f2a97faf423a
 F ext/wasm/api/sqlite3-worker1.c-pp.js da509469755035e919c015deea41b4514b5e84c12a1332e6cc8d42cb2cc1fb75
 F ext/wasm/batch-runner.html 4deeed44fe41496dc6898d9fb17938ea3291f40f4bfb977e29d0cef96fbbe4c8
 F ext/wasm/batch-runner.js 0dad6a02ad796f1003d3b7048947d275c4d6277f63767b8e685c27df8fdac93e
@@ -575,8 +577,8 @@ F ext/wasm/example_extra_init.c 2347cd69d19d839ef4e5e77b7855103a7fe3ef2af86f2e8c
 F ext/wasm/fiddle.make fa2ba6e90457ba2a71cb745f200d409caf773076df75ae5b177cc225d7627a11
 F ext/wasm/fiddle/emscripten.css 3d253a6fdb8983a2ac983855bfbdd4b6fa1ff267c28d69513dd6ef1f289ada3f
 F ext/wasm/fiddle/fiddle-worker.js e0153f9af6500805c6f09c0b3cfdb7d857e9d6863dbee9d50d1628fccf5f4b4d
+F ext/wasm/fiddle/fiddle.html 550c5aafce40bd218de9bf26192749f69f9b10bc379423ecd2e162bcef885c08
 F ext/wasm/fiddle/fiddle.js 974b995119ac443685d7d94d3b3c58c6a36540e9eb3fed7069d5653284071715
-F ext/wasm/fiddle/index.html 5daf54e8f3d7777cbb1ca4f93affe28858dbfff25841cb4ab81d694efed28ec2
 F ext/wasm/index-dist.html 22379774f0ad4edcaaa8cf9c674c82e794cc557719a8addabed74eb8069d412e
 F ext/wasm/index.html 4e7847b909f4ae0da8c829b150b79454050e53b3658431f138636257729cd42b
 F ext/wasm/jaccwabyt/jaccwabyt.js 1264710db3cfbcb6887d95665b7aeba60c1126eaef789ca4cf1a4a17d5bc7f54
@@ -604,7 +606,7 @@ F ext/wasm/wasmfs.make 8a4955882aaa0783b3f60a9484a1f0f3d8b6f775c0fcd17c082f31966
 F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895 x
 F ltmain.sh 3ff0879076df340d2e23ae905484d8c15d5fdea8
 F magic.txt 5ade0bc977aa135e79e3faaea894d5671b26107cc91e70783aa7dc83f22f3ba0
-F main.mk e18c03071dbb9da424212ba2a1ea331ae0e8f6d7d51283b7ad610c52ea11229c
+F main.mk 5280f58fa05801656870b486cc130e0d9a600ce53275171a0b1c07eaf121660f
 F mptest/config01.test 3c6adcbc50b991866855f1977ff172eb6d901271
 F mptest/config02.test 4415dfe36c48785f751e16e32c20b077c28ae504
 F mptest/crash01.test 61e61469e257df0850df4293d7d4d6c2af301421
@@ -623,13 +625,13 @@ F src/auth.c 19b7ccacae3dfba23fc6f1d0af68134fa216e9040e53b0681b4715445ea030b4
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
 F src/bitvec.c 9eac5f42c11914d5ef00a75605bb205e934f435c579687f985f1f8b0995c8645
 F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
-F src/btree.c 7a37bdf09f338561880860681cb03499a60c3bb0869e539c58bc1d2cdd705ff2
+F src/btree.c a2f42c88fd30300df4c5d8b04a366b78844355b76a74acf46b6e68d36f33a7e0
 F src/btree.h 03e3356f5208bcab8eed4e094240fdac4a7f9f5ddf5e91045ce589f67d47c240
 F src/btreeInt.h 91a9e0c41a0e71fa91a742ec285c63dd8dcb38b73d14fae0ed7209174ff0fdc1
 F src/build.c a8ae3b32d9aa9bbd2c0e97d7c0dd80def9fbca408425de1608f57ee6f47f45f4
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
-F src/ctime.c cff2b493de894383832347c3a3f936a05f4e089a92b42366838da1735f3848b5
+F src/ctime.c 40fa0e42b54f2a5c49a167ebe3141609e3591e39fc037e0f767f601e889526b1
 F src/date.c f73f203b3877cef866c60ab402aec2bf89597219b60635cf50cbe3c5e4533e94
 F src/dbpage.c f3eea5f7ec47e09ee7da40f42b25092ecbe961fc59566b8e5f705f34335b2387
 F src/dbstat.c ec92074baa61d883de58c945162d9e666c13cd7cf3a23bc38b4d1c4d0b2c2bef
@@ -637,14 +639,14 @@ F src/delete.c cb766727c78e715f9fb7ec8a7d03658ed2a3016343ca687acfcec9083cdca500
 F src/expr.c 1affe0cc049683ef0ef3545d9b6901508556b0ef7e2892a344c3df6d7288d79d
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 F src/fkey.c a7fcbf7e66d14dbb73cf49f31489ebf66d0e6006c62b95246924a3bae9f37b36
-F src/func.c dd1ecd1be6aaa67c9fa723f841e05e1536314c6aaa0509e25289b310f64dbb9c
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 F src/global.c 29f56a330ed9d1b5cd9b79ac0ca36f97ac3afc730ff8bfa987b0db9e559d684d
 F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
 F src/insert.c 3f0a94082d978bbdd33c38fefea15346c6c6bffb70bc645a71dc0f1f87dd3276
-F src/json.c ae840f87b418f039f5d336b488933d09396bd31e6b31e855b93055ccaee4e255
+F src/json.c 51141f1c09ccb177057e5813e6302a5e32e5ba88cc4a756318a35081010fc6df
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 98cfba10989b3da6f1807ad42444017742db7f100a54f1032af7a8b1295912c0
 F src/main.c fde8f13c876a658b4e8b74b77d875ca887915c174ea6a2f3122d80966f93d865
@@ -671,20 +673,20 @@ F src/os_setup.h 6011ad7af5db4e05155f385eb3a9b4470688de6f65d6166b8956e58a3d87210
 F src/os_unix.c 2e8b12107f75d1bd16412f312b4c5d5103191807a37836d3b81beb26436ad81b
 F src/os_win.c 4a50a154aeebc66a1f8fb79c1ff6dd5fe3d005556533361e0d460d41cb6a45a8
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
-F src/pager.c 993445a19b611d473ca007542ab3149840661a4c7e9f2d9e1ec008b7cc2abe78
-F src/pager.h f4d33fec8052603758792045493423b8871a996da2d0973927b7d36cd6070473
+F src/pager.c e7af170f5799a5edd77fc267e81cb0292e1a1cb7b488b62c6e2fff78aedc2efb
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 F src/parse.y aeb7760d41cfa86465e3adba506500c021597049fd55f82a30e5b7045862c28c
 F src/pcache.c 040b165f30622a21b7a9a77c6f2e4877a32fb7f22d4c7f0d2a6fa6833a156a75
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 F src/pcache1.c 602acb23c471bb8d557a6f0083cc2be641d6cafcafa19e481eba7ef4c9ca0f00
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 F src/pragma.h e690a356c18e98414d2e870ea791c1be1545a714ba623719deb63f7f226d8bb7
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 F src/resolve.c 37953a5f36c60bea413c3c04efcd433b6177009f508ef2ace0494728912fe2e9
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
-F src/select.c 5f545a2c8702d4d3430bbb188cfec47d6c122d899061ef00cbe56af14591c574
+F src/select.c e9fb48546ab1882639a3a960383f6342dddb776c0227615f8e19de51f0102f68
 F src/shell.c.in 2f9be25294b68b07e7e81f0adcec4475aba6011b64f160e414efe226910c4d7b
 F src/sqlite.h.in 73a366c1c45d5ac9888cfe81c458826a44498531d106cfb4f328193ab5f6f17d
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -714,7 +716,7 @@ F src/test_demovfs.c 38a459d1c78fd9afa770445b224c485e079018d6ac07332ff9bd07b54d2
 F src/test_devsym.c 649434ed34d0b03fbd5a6b42df80f0f9a7e53f94dd1710aad5dd8831e91c4e86
 F src/test_fs.c ba1e1dc18fd3159fdba0b9c4256f14032159785320dfbd6776eb9973cb75d480
 F src/test_func.c 24df3a346c012b1fc9e1001d346db6054deb426db0a7437e92490630e71c9b0a
-F src/test_hexio.c 9478e56a0f08e07841a014a93b20e4ba2709ab56d039d1ca8020e26846aa19bd
+F src/test_hexio.c a605a100e628d39330044ae5f34cb19d50843061ed3178c3f83b37aef65f7e0a
 F src/test_init.c f2cc4774b7c9140f76e45ecbb2ae219f68e3acbbe248c0179db666a70eae9f08
 F src/test_intarray.c 39b4181662a0f33a427748d87218e7578d913e683dc27eab7098bb41617cac71
 F src/test_intarray.h 6c3534641108cd1bea517a8e117dcba237081310a29a4c35bd2190caa8972293
@@ -735,7 +737,7 @@ F src/test_schema.c f5d6067dfc2f2845c4dd56df63e66ee826fb23877855c785f75cc2ca83fd
 F src/test_sqllog.c 540feaea7280cd5f926168aee9deb1065ae136d0bbbe7361e2ef3541783e187a
 F src/test_superlock.c 4839644b9201da822f181c5bc406c0b2385f672e
 F src/test_syscall.c 9fdb13b1df05e639808d44fcb8f6064aaded32b6565c00b215cfd05a060d1aca
-F src/test_tclsh.c 3ff5d188a72f00807425954ea3b493dfd3a4b890ecc6700ea83bad2fd1332ecf
+F src/test_tclsh.c 01c76e2ee362cda246710c476351b105371cf4620857c8492121858744998dc9
 F src/test_tclvar.c 33ff42149494a39c5fbb0df3d25d6fafb2f668888e41c0688d07273dcb268dfc
 F src/test_thread.c 7ddcf0c8b79fa3c1d172f82f322302c963d923cdb503c6171f3c8081586d0b01
 F src/test_vdbecov.c f60c6f135ec42c0de013a1d5136777aa328a776d33277f92abac648930453d43
@@ -754,11 +756,11 @@ F src/upsert.c fa125a8d3410ce9a97b02cb50f7ae68a2476c405c76aa692d3acf6b8586e9242
 F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
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 F src/vacuum.c 604fcdaebe76f3497c855afcbf91b8fa5046b32de3045bab89cc008d68e40104
-F src/vdbe.c 346d848a0bf8128e3e3722c5406f4bde6c32d7093b93402c6f8e0718d19305c3
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 F src/vdbe.h 41485521f68e9437fdb7ec4a90f9d86ab294e9bb8281e33b235915e29122cfc0
 F src/vdbeInt.h 949669dfd8a41550d27dcb905b494f2ccde9a2e6c1b0b04daa1227e2e74c2b2c
 F src/vdbeapi.c 37341acd781fda162e8cf4d9fc2eaea2febad3b365877a9d7233b8c6d0960d85
-F src/vdbeaux.c e3aa5c46827cd95e0fc4d0f302fa3e901ab5f07258fdbb42709eeef40f63018d
+F src/vdbeaux.c ad53a8294930a1bf305e6cdedd8366c119f54c3986450c432be655b5c63fea65
 F src/vdbeblob.c 2516697b3ee8154eb8915f29466fb5d4f1ae39ee8b755ea909cefaf57ec5e2ce
 F src/vdbemem.c 317b9f48708139db6239ade40c7980b4bc8233168383690d588dad6d8437f722
 F src/vdbesort.c 0d40dca073c94e158ead752ef4225f4fee22dee84145e8c00ca2309afb489015
@@ -766,8 +768,8 @@ F src/vdbetrace.c fe0bc29ebd4e02c8bc5c1945f1d2e6be5927ec12c06d89b03ef2a4def34bf8
 F src/vdbevtab.c 57fa8f56478e5b5cb558cb425e7878515e0a105c54f96f1d1bbf4b9433529254
 F src/vtab.c 1ecf8c3745d29275688d583e12822fa984d421e0286b5ef50c137bc3bf6d7a64
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
-F src/wal.c 01e051a1e713d9eabdb25df38602837cec8f4c2cae448ce2cf6accc87af903e9
-F src/wal.h ba252daaa94f889f4b2c17c027e823d9be47ce39da1d3799886bbd51f0490452
+F src/wal.c ffbca820a2ee9827269488cf8e1356ae66ad1e65da636da4eb4f3fcdf9d6ddd5
+F src/wal.h 97b8a9903387401377b59507e86b93a148ef1ad4e5ce0f23659a12dcdce56af2
 F src/walker.c 7c7ea0115345851c3da4e04e2e239a29983b61fb5b038b94eede6aba462640e2
 F src/where.c b8917792f1e0dbfa28fb29e6cd3d560060d69667be0ba4c491cbc772363264f5
 F src/whereInt.h c7d19902863beadec1d04e66aca39c0bcd60b74f05f0eaa7422c7005dfc5d51a
@@ -939,7 +941,7 @@ F test/corrupt6.test fc6a891716139665dae0073b6945e3670bf92568
 F test/corrupt7.test ffa86896fe63a3d00b0a131e1e64f402e4da9f7e5d89609d6501c851e511d73a
 F test/corrupt8.test 2399dfe40d2c0c63af86706e30f3e6302a8d0516
 F test/corrupt9.test 730a3db08d4ab9aa43392ea30d9c2b4879cbff85
-F test/corruptA.test 112f4b2ae0b95ebf3ea63718642fb969a93acea557ace3a307234d19c245989b
+F test/corruptA.test 56e8f321adaf3411960e9d2c7136669d8e1a91cbde6cf401ea84e6d6c7ccbe10
 F test/corruptB.test 73a8d6c0b9833697ecf16b63e3c5c05c945b5dec
 F test/corruptC.test 9cf32275dae3ca33f645afe5d1d3f5ba5ac2af2b0833dfb5282f9dccb6fb81bb
 F test/corruptD.test a828c788535946a372a56a750b242cd96287cd823657abe5a73c5e51b91bdd28
@@ -1156,7 +1158,7 @@ F test/fts4umlaut.test fcaca4471de7e78c9d1f7e8976e3e8704d7d8ad979d57a739d00f3f75
 F test/fts4unicode.test 82a9c16b68ba2f358a856226bb2ee02f81583797bc4744061c54401bf1a0f4c9
 F test/fts4upfrom.test f25835162c989dffd5e2ef91ec24c4848cc9973093e2d492d1c7b32afac1b49d
 F test/full.test 6b3c8fb43c6beab6b95438c1675374b95fab245d
-F test/func.test 2acd982669b2c15ceccc046385b458e985f90c9ca58b14d0ef75eec79c32f45b
+F test/func.test cbcf086273529d4a99b7199086da637a99039d2cad81dd7d7c4c9e25258ae164
 F test/func2.test 772d66227e4e6684b86053302e2d74a2500e1e0f
 F test/func3.test 600a632c305a88f3946d38f9a51efe145c989b2e13bd2b2a488db47fe76bab6a
 F test/func4.test 2285fb5792d593fef442358763f0fd9de806eda47dbc7a5934df57ffdc484c31
@@ -1274,7 +1276,7 @@ F test/json/json-generator.tcl dc0dd0f393800c98658fc4c47eaa6af29d4e17527380cd286
 F test/json/json-q1.txt 65f9d1cdcc4cffa9823fb73ed936aae5658700cd001fde448f68bfb91c807307
 F test/json/json-speed-check.sh 8b7babf530faa58bd59d6d362cec8e9036a68c5457ff46f3b1f1511d21af6737 x
 F test/json101.test dc9d5a2a5b1fd1b54dbd71c538b17933cc98d84b4c1f821ead754933663dca55
-F test/json102.test 24f6f204f9cde45b971016691d0b92a9b4c58040d699e36d6b12cb165f9083ff
+F test/json102.test 4c69694773a470f1fda34e5f4ba24920b35184fb66050b450fc2ef9ab5ad310b
 F test/json103.test 53df87f83a4e5fa0c0a56eb29ff6c94055c6eb919f33316d62161a8880112dbe
 F test/json104.test 1b844a70cddcfa2e4cd81a5db0657b2e61e7f00868310f24f56a9ba0114348c1
 F test/json105.test 11670a4387f4308ae0318cadcbd6a918ea7edcd19fbafde020720a073952675d
@@ -1411,7 +1413,7 @@ F test/pcache.test c8acbedd3b6fd0f9a7ca887a83b11d24a007972b
 F test/pcache2.test af7f3deb1a819f77a6d0d81534e97d1cf62cd442
 F test/pendingrace.test cbdf0f74bc939fb43cebad64dda7a0b5a3941a10b7e9cc2b596ff3e423a18156
 F test/percentile.test 4243af26b8f3f4555abe166f723715a1f74c77ff
-F test/permutations.test f7caf8dd5c7b1da74842a48df116f7f193399c656d4ffc805cd0d9658568c675
+F test/permutations.test 58188152f3e0e319cd916f5f6e1afb34c8d3a5219fe49fe62c0c706514e54970
 F test/pg_common.tcl 3b27542224db1e713ae387459b5d117c836a5f6e328846922993b6d2b7640d9f
 F test/pragma.test 57a36226218c03cfb381019fe43234b2cefbd8a1f12825514f906a17ccf7991e
 F test/pragma2.test e5d5c176360c321344249354c0c16aec46214c9f
@@ -1435,7 +1437,7 @@ F test/quote.test ffb40f0eb7a25c1d8cfe11ee2fe67f8e85fbf3fed348810834114be1fdada1
 F test/randexpr1.tcl 40dec52119ed3a2b8b2a773bce24b63a3a746459
 F test/randexpr1.test eda062a97e60f9c38ae8d806b03b0ddf23d796df
 F test/rbu.test 168573d353cd0fd10196b87b0caa322c144ef736
-F test/rdonly.test 64e2696c322e3538df0b1ed624e21f9a23ed9ff8
+F test/rdonly.test 21e99ee237265d0cf95a0c84b50c784e834acaa4ef05d92a27b262626a656682
 F test/recover.test fd5199f928757cb308661b5fdca1abc19398a798ff7f24b57c3071e9f8e0471e
 F test/regexp1.test 8f2a8bc1569666e29a4cee6c1a666cd224eb6d50e2470d1dc1df995170f3e0f1
 F test/regexp2.test 55ed41da802b0e284ac7e2fe944be3948f93ff25abbca0361a609acfed1368b5
@@ -1466,11 +1468,11 @@ F test/rowvaluefault.test 963ae9cdaed30a85a29668dd514e639f3556cae903ee9f172ea972
 F test/rowvaluevtab.test cd9747bb3f308086944c07968f547ad6b05022e698d80b9ffbdfe09ce0b8da6f
 F test/rtree.test 0c8d9dd458d6824e59683c19ab2ffa9ef946f798
 F test/run-wordcount.sh 891e89c4c2d16e629cd45951d4ed899ad12afc09
-F test/savepoint.test 6e9804a17767f08432c7a5e738b9a8f4b891d243110b63d3a41d270d3d1378ec
+F test/savepoint.test 63a120ec4fbbd5025b238c259d12ed0516fbf4bca6384041cb995ade9a5f00d2
 F test/savepoint2.test 9b8543940572a2f01a18298c3135ad0c9f4f67d7
 F test/savepoint4.test c8f8159ade6d2acd9128be61e1230f1c1edc6cc0
 F test/savepoint5.test 0735db177e0ebbaedc39812c8d065075d563c4fd
-F test/savepoint6.test f41279c5e137139fa5c21485773332c7adb98cd7
+F test/savepoint6.test 48a645a7bb3a59a6fcf06a7364cfe5b655c336760de39068f7c241b0fc80d963
 F test/savepoint7.test cde525ea3075283eb950cdcdefe23ead4f700daa
 F test/savepointfault.test f044eac64b59f09746c7020ee261734de82bf9b2
 F test/scanstatus.test b249328caf4d317e71058006872b8012598a5fa045b30bf24a81eeff650ab49e
@@ -1501,7 +1503,7 @@ F test/selectD.test 6d1909b49970bf92f45ce657505befcef5fc7cbc13544e18103a316d3218
 F test/selectE.test a8730ca330fcf40ace158f134f4fe0eb00c7edbf
 F test/selectF.test 21c94e6438f76537b72532fa9fd4710cdd455fc3
 F test/selectG.test 089f7d3d7e6db91566f00b036cb353107a2cca6220eb1cb264085a836dae8840
-F test/selectH.test 88237ded5925adfb3f27fdafb5428c2ffc4d61e313bceb854e225ffc3ef0d206
+F test/selectH.test 0b54599f1917d99568c9b929df22ec6261ed7b6d2f02a46b5945ef81b7871aac
 F test/session.test 78fa2365e93d3663a6e933f86e7afc395adf18be
 F test/sessionfuzz-data1.db 1f8d5def831f19b1c74571037f0d53a588ea49a6c4ca2a028fc0c27ef896dbcb
 F test/sessionfuzz.c 5eef09af01eeff6f20250ae4c0112c2e576e4d2f2026cc9a49dc5be6886fa6ee
@@ -1602,9 +1604,9 @@ F test/temptable.test d2c9b87a54147161bcd1822e30c1d1cd891e5b30
 F test/temptable2.test 76821347810ecc88203e6ef0dd6897b6036ac788e9dd3e6b04fd4d1631311a16
 F test/temptable3.test d11a0974e52b347e45ee54ef1923c91ed91e4637
 F test/temptrigger.test 38f0ca479b1822d3117069e014daabcaacefffcc
-F test/tester.tcl 68454ef88508c196d19e8694daa27bff7107a91857799eaa12f417188ae53ede
+F test/tester.tcl e6b9adcf4e56aa5c658501c10650646fee467b85d51a4ac80263d2cdae3993ba
 F test/testrunner.tcl a9fee4df57276bc9e446961b160068c269da5902cc8ffc3e8852d77626b7594c
-F test/testrunner_data.tcl c448693eb6fdbadb78cb26f6253d4f335666f9836f988afa575de960b666b19f
+F test/testrunner_data.tcl 968cfee74688eb698b6917b7e53aba2993a1789430192d5efd27d2173c2e36c6
 F test/thread001.test a0985c117eab62c0c65526e9fa5d1360dd1cac5b03bde223902763274ce21899
 F test/thread002.test c24c83408e35ba5a952a3638b7ac03ccdf1ce4409289c54a050ac4c5f1de7502
 F test/thread003.test ee4c9efc3b86a6a2767516a37bd64251272560a7
@@ -1825,7 +1827,7 @@ F test/upsert3.test 88d7d590a1948a9cb6eac1b54b0642f67a9f35a1fc0f19b200e97d5d39e3
 F test/upsert4.test 25d2a1da92f149331ae0c51ca6e3eee78189577585eab92de149900d62994fa5
 F test/upsert5.test fff0dcfce73c649204543088d8e5bde01172676063ec9b8f8fc7f195abc386fe
 F test/upsertfault.test f21ca47740841fdb4d61acfa7b17646d773e67724fe8c185b71c018db8a94b35
-F test/uri.test c1abaaaa28e9422d61e5f3f9cbc8ef993ec49fe802f581520731708561d49384
+F test/uri.test 8f27eaa41804099fca15101e30fd1b29aebbebf32d4e3c24614fa6319216936d
 F test/uri2.test 9d3ba7a53ee167572d53a298ee4a5d38ec4a8fb7
 F test/userauth01.test e740a2697a7b40d7c5003a7d7edaee16acd349a9
 F test/utf16align.test 9fde0bb5d3a821594aa68c6829ab9c5453a084384137ebb9f6153e2d678039da
@@ -1868,8 +1870,20 @@ F test/vtab_shared.test 5253bff2355a9a3f014c15337da7e177ab0ef8ad
 F test/vtabdistinct.test 7688f0889358f849fd60bbfde1ded38b014b18066076d4bfbb75395804dfe072
 F test/vtabdrop.test 65d4cf6722972e5499bdaf0c0d70ee3b8133944a4e4bc31862563f32a7edca12
 F test/vtabrhs1.test 9b5ecbc74a689500c33a4b2b36761f9bcc22fcc4e3f9d21066ee0c9c74cf5f6c
-F test/wal.test b7cc6984709f54afbf8441747ced1f646af120bf0c1b1d847bfa39306fbea089
+F test/wal.test 07d61ee522bc203235a7979645d6c5d84f86882afad5b678532ee37b5b85b133
 F test/wal2.test 31f6e2c404b9f2cdf9ca19b105a1742fdc19653c2c936da39e3658c617524046
+F test/wal2big.test 829141cbecdda4329db8fa38705424c4a73db72a06b9540b06811a825d330409
+F test/wal2fault.test 2e8e60cacd5bcd451618aeffd05f676894d17202d3e2986e288d36e2c5993249
+F test/wal2lock.test 0ef98d72dc6bcf7711dedd684760488400d9a9a6eec0dc5d3822060437793552
+F test/wal2openclose.test 2b26be723ea7f4263c8d5d70b37efd1c359561a0526e39466c45fe8e6478daee
+F test/wal2recover.test 28b3fa0acb4e8725211a02803cd51116cd048841a876224f244af78039ba34fa
+F test/wal2recover2.test 3fe5d5932b16a3a38304a85bafed1f965faef40c230fd450838a0502e61343bb
+F test/wal2recover3.test 4a91689e165a38bc401736e6518188c2b0ff4fa1566d1810b8867536db128177
+F test/wal2rewrite.test 6ca6f631ffcf871240beab5f02608913fd075c6d0d31310b026c8383c65c9f9c
+F test/wal2rollback.test 23adc4a099b23f6aaea8b04fdca1c35861d887dd80f8be7da2d5273eb777e428
+F test/wal2savepoint.test 2c82bd6a6ee5066c156040d2e9c2415646fcf96116ae7ad127eaf0c0b4a85f22
+F test/wal2simple.test 320a08927f307d0ead26fa3fcef4e3f64279f49be9504f918cb33294f75aeec8
+F test/wal2snapshot.test 7a5f4629a3c43a43c3440b8b2ea9f07de91a46b0b9eea5f08f62b5bf5b6468df
 F test/wal3.test 5de023bb862fd1eb9d2ad26fa8d9c43abb5370582e5b08b2ae0d6f93661bc310
 F test/wal4.test 4744e155cd6299c6bd99d3eab1c82f77db9cdb3c
 F test/wal5.test 9c11da7aeccd83a46d79a556ad11a18d3cb15aa9
@@ -1895,7 +1909,7 @@ F test/walnoshm.test 84ca10c544632a756467336b7c3b864d493ee496
 F test/waloverwrite.test dad2f26567f1b45174e54fbf9a8dc1cb876a7f03
 F test/walpersist.test 8d78a1ec91299163451417b451a2bac3481f8eb9f455b1ca507a6625c927ca6e
 F test/walprotocol.test 1b3f922125e341703f6e946d77fdc564d38fb3e07a9385cfdc6c99cac1ecf878
-F test/walprotocol2.test 7d3b6b4bf0b12f8007121b1e6ef714bc99101fb3b48e46371df1db868eebc131
+F test/walprotocol2.test 7e4bedd5ee83607e2928ac438bf7332a396b980d3e02aa0746509ce11ad1f13c
 F test/walro.test cb438d05ba0d191f10b688e39c4f0cd5b71569a1d1f4440e5bdf3c6880e08c20
 F test/walro2.test 33955a6fd874dd9724005e17f77fef89d334b3171454a1256fe4941a96766cdc
 F test/walrofault.test c70cb6e308c443867701856cce92ad8288cd99488fa52afab77cca6cfd51af68
@@ -2014,7 +2028,7 @@ F tool/max-limits.c cbb635fbb37ae4d05f240bfb5b5270bb63c54439
 F tool/merge-test.tcl de76b62f2de2a92d4c1ca4f976bce0aea6899e0229e250479b229b2a1914b176
 F tool/mkautoconfamal.sh f62353eb6c06ab264da027fd4507d09914433dbdcab9cb011cdc18016f1ab3b8
 F tool/mkccode.tcl 86463e68ce9c15d3041610fedd285ce32a5cf7a58fc88b3202b8b76837650dbe x
-F tool/mkctimec.tcl aca4b83e49aecf10368cd5d11bc4847061041ade026db5bd8da17ef201f1403b x
+F tool/mkctimec.tcl ad237e2d4169ffe5f3c7c24fe31a74e9003dfaa066d6d108c60399af8a37e0ad x
 F tool/mkkeywordhash.c b9faa0ae7e14e4dbbcd951cddd786bf46b8a65bb07b129ba8c0cfade723aaffd
 F tool/mkmsvcmin.tcl 8897d515ef7f94772322db95a3b6fce6c614d84fe0bdd06ba5a1c786351d5a1d
 F tool/mkopcodec.tcl 33d20791e191df43209b77d37f0ff0904620b28465cca6990cf8d60da61a07ef
@@ -2092,11 +2106,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 3f5bec9a684f6b3d88383617831862fc5595a51ad99ec12430ac6650b704ccbb
-R 0c01ee5f49ac8bbf7d5b3e02bf525f93
-T +sym-major-release *
-T +sym-release *
-T +sym-version-3.43.0 *
+P b4491c9fbbc0f55dfffafe8811a0df530dbb3221fc94ba93c48539e4759eb3bd
+Q +79a920c036c91bbae737e4f4c5310052d26407fe7d23bcf95a2aa79ea3773a0f
+Q +dde9fcbde16bf71c4ab708e2db769b9cefacd0d7bce8223a46bf1264ae7ddecd
+R af737207812e837b5ceb552ea0061b6a
 U drh
-Z 2bd48930e1a5ff814b90ece6e1f4c0d0
+Z a35f8986424353d3efe952571fa9e493
 # Remove this line to create a well-formed Fossil manifest.
@@ -1 +1 @@
-0f80b798b3f4b81a7bb4233c58294edd0f1156f36b6ecf5ab8e83631d468778c
+f82b1a0bde3f836e25b704084674e3bee609ecea3dc9ef259218989bd1198482
@@ -3261,10 +3261,10 @@ static int lockBtree(BtShared *pBt){
      goto page1_init_failed;
    }
 #else
-    if( page1[18]>2 ){
+    if( page1[18]>3 ){
      pBt->btsFlags |= BTS_READ_ONLY;
    }
-    if( page1[19]>2 ){
+    if( page1[19]>3 ){
      goto page1_init_failed;
    }

@@ -3276,9 +3276,9 @@ static int lockBtree(BtShared *pBt){
    ** may not be the latest version - there may be a newer one in the log
    ** file.
    */
-    if( page1[19]==2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
+    if( page1[19]>=2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
      int isOpen = 0;
-      rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
+      rc = sqlite3PagerOpenWal(pBt->pPager, (page1[19]==3), &isOpen);
      if( rc!=SQLITE_OK ){
        goto page1_init_failed;
      }else{
@@ -11302,7 +11302,7 @@ int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
  BtShared *pBt = pBtree->pBt;
  int rc;                         /* Return code */

-  assert( iVersion==1 || iVersion==2 );
+  assert( iVersion==1 || iVersion==2 || iVersion==3 );

  /* If setting the version fields to 1, do not automatically open the
  ** WAL connection, even if the version fields are currently set to 2.
@@ -770,6 +770,7 @@ static const char * const sqlite3azCompileOpt[] = {
 #ifdef SQLITE_VDBE_COVERAGE
  "VDBE_COVERAGE",
 #endif
+"WAL2",
 #ifdef SQLITE_WIN32_MALLOC
  "WIN32_MALLOC",
 #endif
@@ -1816,8 +1816,10 @@ static void sumFinalize(sqlite3_context *context){
    if( p->approx ){
      if( p->ovrfl ){
        sqlite3_result_error(context,"integer overflow",-1);
-      }else{
+      }else if( !sqlite3IsNaN(p->rErr) ){
        sqlite3_result_double(context, p->rSum+p->rErr);
+      }else{
+        sqlite3_result_double(context, p->rSum);
      }
    }else{
      sqlite3_result_int64(context, p->iSum);
@@ -1830,7 +1832,8 @@ static void avgFinalize(sqlite3_context *context){
  if( p && p->cnt>0 ){
    double r;
    if( p->approx ){
-      r = p->rSum+p->rErr;
+      r = p->rSum;
+      if( !sqlite3IsNaN(p->rErr) ) r += p->rErr;
    }else{
      r = (double)(p->iSum);
    }
@@ -1843,7 +1846,8 @@ static void totalFinalize(sqlite3_context *context){
  p = sqlite3_aggregate_context(context, 0);
  if( p ){
    if( p->approx ){
-      r = p->rSum+p->rErr;
+      r = p->rSum;
+      if( !sqlite3IsNaN(p->rErr) ) r += p->rErr;
    }else{
      r = (double)(p->iSum);
    }
@@ -2484,7 +2484,9 @@ static void jsonArrayLengthFunc(
  }
  if( pNode->eType==JSON_ARRAY ){
    while( 1 /*exit-by-break*/ ){
-      for(i=1; i<=pNode->n; n++){
+      i = 1;
+      while( i<=pNode->n ){
+        if( (pNode[i].jnFlags & JNODE_REMOVE)==0 ) n++;
        i += jsonNodeSize(&pNode[i]);
      }
      if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
@@ -789,20 +789,6 @@ static const unsigned char aJournalMagic[] = {
 # define USEFETCH(x) 0
 #endif

-/*
-** The argument to this macro is a file descriptor (type sqlite3_file*).
-** Return 0 if it is not open, or non-zero (but not 1) if it is.
-**
-** This is so that expressions can be written as:
-**
-**   if( isOpen(pPager->jfd) ){ ...
-**
-** instead of
-**
-**   if( pPager->jfd->pMethods ){ ...
-*/
-#define isOpen(pFd) ((pFd)->pMethods!=0)
-
 #ifdef SQLITE_DIRECT_OVERFLOW_READ
 /*
 ** Return true if page pgno can be read directly from the database file
@@ -934,6 +920,7 @@ static int assert_pager_state(Pager *p){
        assert( isOpen(p->jfd)
             || p->journalMode==PAGER_JOURNALMODE_OFF
             || p->journalMode==PAGER_JOURNALMODE_WAL
+             || p->journalMode==PAGER_JOURNALMODE_WAL2
        );
      }
      assert( pPager->dbOrigSize==pPager->dbFileSize );
@@ -948,6 +935,7 @@ static int assert_pager_state(Pager *p){
      assert( isOpen(p->jfd)
           || p->journalMode==PAGER_JOURNALMODE_OFF
           || p->journalMode==PAGER_JOURNALMODE_WAL
+           || p->journalMode==PAGER_JOURNALMODE_WAL2
           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
      );
      assert( pPager->dbOrigSize<=pPager->dbHintSize );
@@ -960,6 +948,7 @@ static int assert_pager_state(Pager *p){
      assert( isOpen(p->jfd)
           || p->journalMode==PAGER_JOURNALMODE_OFF
           || p->journalMode==PAGER_JOURNALMODE_WAL
+           || p->journalMode==PAGER_JOURNALMODE_WAL2
           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
      );
      break;
@@ -2058,7 +2047,7 @@ static int pager_end_transaction(Pager *pPager, int hasSuper, int bCommit){
      }
      pPager->journalOff = 0;
    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
-      || (pPager->exclusiveMode && pPager->journalMode!=PAGER_JOURNALMODE_WAL)
+      || (pPager->exclusiveMode && pPager->journalMode<PAGER_JOURNALMODE_WAL)
    ){
      rc = zeroJournalHdr(pPager, hasSuper||pPager->tempFile);
      pPager->journalOff = 0;
@@ -2073,6 +2062,7 @@ static int pager_end_transaction(Pager *pPager, int hasSuper, int bCommit){
      assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE
           || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
           || pPager->journalMode==PAGER_JOURNALMODE_WAL
+           || pPager->journalMode==PAGER_JOURNALMODE_WAL2
      );
      sqlite3OsClose(pPager->jfd);
      if( bDelete ){
@@ -3210,6 +3200,10 @@ static int pagerBeginReadTransaction(Pager *pPager){
  if( rc!=SQLITE_OK || changed ){
    pager_reset(pPager);
    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);
+    assert( pPager->journalMode==PAGER_JOURNALMODE_WAL
+         || pPager->journalMode==PAGER_JOURNALMODE_WAL2
+    );
+    pPager->journalMode = sqlite3WalJournalMode(pPager->pWal);
  }

  return rc;
@@ -3305,9 +3299,9 @@ static int pagerOpenWalIfPresent(Pager *pPager){
          rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
        }else{
          testcase( sqlite3PcachePagecount(pPager->pPCache)==0 );
-          rc = sqlite3PagerOpenWal(pPager, 0);
+          rc = sqlite3PagerOpenWal(pPager, 0, 0);
        }
-      }else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
+      }else if( pPager->journalMode>=PAGER_JOURNALMODE_WAL ){
        pPager->journalMode = PAGER_JOURNALMODE_DELETE;
      }
    }
@@ -4811,6 +4805,7 @@ int sqlite3PagerOpen(
    nPathname + 8 + 1 +                  /* Journal filename */
 #ifndef SQLITE_OMIT_WAL
    nPathname + 4 + 1 +                  /* WAL filename */
+    nPathname + 5 + 1 +                  /* Second WAL filename */
 #endif
    3                                    /* Terminator */
  );
@@ -4863,6 +4858,8 @@ int sqlite3PagerOpen(
    sqlite3FileSuffix3(zFilename, pPager->zWal);
    pPtr = (u8*)(pPager->zWal + sqlite3Strlen30(pPager->zWal)+1);
 #endif
+    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname;
+    memcpy(pPtr, "-wal2", 5);             pPtr += 5 + 1;
  }else{
    pPager->zWal = 0;
  }
@@ -7277,7 +7274,8 @@ int sqlite3PagerSetJournalMode(Pager *pPager, int eMode){
            || eMode==PAGER_JOURNALMODE_OFF       /* 2 */
            || eMode==PAGER_JOURNALMODE_TRUNCATE  /* 3 */
            || eMode==PAGER_JOURNALMODE_MEMORY    /* 4 */
-            || eMode==PAGER_JOURNALMODE_WAL       /* 5 */ );
+            || eMode==PAGER_JOURNALMODE_WAL       /* 5 */
+            || eMode==PAGER_JOURNALMODE_WAL2      /* 6 */ );

  /* This routine is only called from the OP_JournalMode opcode, and
  ** the logic there will never allow a temporary file to be changed
@@ -7311,9 +7309,12 @@ int sqlite3PagerSetJournalMode(Pager *pPager, int eMode){
    assert( (PAGER_JOURNALMODE_MEMORY & 5)==4 );
    assert( (PAGER_JOURNALMODE_OFF & 5)==0 );
    assert( (PAGER_JOURNALMODE_WAL & 5)==5 );
+    assert( (PAGER_JOURNALMODE_WAL2 & 5)==4 );

    assert( isOpen(pPager->fd) || pPager->exclusiveMode );
-    if( !pPager->exclusiveMode && (eOld & 5)==1 && (eMode & 1)==0 ){
+    if( !pPager->exclusiveMode && (eOld & 5)==1 && (eMode & 1)==0 
+     && eMode!=PAGER_JOURNALMODE_WAL2       /* TODO: fix this if possible */
+    ){
      /* In this case we would like to delete the journal file. If it is
      ** not possible, then that is not a problem. Deleting the journal file
      ** here is an optimization only.
@@ -7488,7 +7489,7 @@ static int pagerExclusiveLock(Pager *pPager){
 ** lock on the database file and use heap-memory to store the wal-index
 ** in. Otherwise, use the normal shared-memory.
 */
-static int pagerOpenWal(Pager *pPager){
+static int pagerOpenWal(Pager *pPager, int bWal2){
  int rc = SQLITE_OK;

  assert( pPager->pWal==0 && pPager->tempFile==0 );
@@ -7509,7 +7510,7 @@ static int pagerOpenWal(Pager *pPager){
  if( rc==SQLITE_OK ){
    rc = sqlite3WalOpen(pPager->pVfs,
        pPager->fd, pPager->zWal, pPager->exclusiveMode,
-        pPager->journalSizeLimit, &pPager->pWal
+        pPager->journalSizeLimit, bWal2, &pPager->pWal
    );
  }
  pagerFixMaplimit(pPager);
@@ -7535,6 +7536,7 @@ static int pagerOpenWal(Pager *pPager){
 */
 int sqlite3PagerOpenWal(
  Pager *pPager,                  /* Pager object */
+  int bWal2,                      /* Open in wal2 mode if not already open */
  int *pbOpen                     /* OUT: Set to true if call is a no-op */
 ){
  int rc = SQLITE_OK;             /* Return code */
@@ -7551,9 +7553,9 @@ int sqlite3PagerOpenWal(
    /* Close any rollback journal previously open */
    sqlite3OsClose(pPager->jfd);

-    rc = pagerOpenWal(pPager);
+    rc = pagerOpenWal(pPager, bWal2);
    if( rc==SQLITE_OK ){
-      pPager->journalMode = PAGER_JOURNALMODE_WAL;
+      pPager->journalMode = bWal2?PAGER_JOURNALMODE_WAL2:PAGER_JOURNALMODE_WAL;
      pPager->eState = PAGER_OPEN;
    }
  }else{
@@ -7575,7 +7577,9 @@ int sqlite3PagerOpenWal(
 int sqlite3PagerCloseWal(Pager *pPager, sqlite3 *db){
  int rc = SQLITE_OK;

-  assert( pPager->journalMode==PAGER_JOURNALMODE_WAL );
+  assert( pPager->journalMode==PAGER_JOURNALMODE_WAL 
+       || pPager->journalMode==PAGER_JOURNALMODE_WAL2
+  );

  /* If the log file is not already open, but does exist in the file-system,
  ** it may need to be checkpointed before the connection can switch to
@@ -7590,7 +7594,7 @@ int sqlite3PagerCloseWal(Pager *pPager, sqlite3 *db){
      );
    }
    if( rc==SQLITE_OK && logexists ){
-      rc = pagerOpenWal(pPager);
+      rc = pagerOpenWal(pPager, 0);
    }
  }
   
@@ -82,6 +82,23 @@ typedef struct PgHdr DbPage;
 #define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */
 #define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
 #define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */
+#define PAGER_JOURNALMODE_WAL2        6   /* Use write-ahead logging mode 2 */
+
+#define isWalMode(x) ((x)==PAGER_JOURNALMODE_WAL || (x)==PAGER_JOURNALMODE_WAL2)
+
+/*
+** The argument to this macro is a file descriptor (type sqlite3_file*).
+** Return 0 if it is not open, or non-zero (but not 1) if it is.
+**
+** This is so that expressions can be written as:
+**
+**   if( isOpen(pPager->jfd) ){ ...
+**
+** instead of
+**
+**   if( pPager->jfd->pMethods ){ ...
+*/
+#define isOpen(pFd) ((pFd)->pMethods!=0)

 /*
 ** Flags that make up the mask passed to sqlite3PagerGet().
@@ -175,7 +192,7 @@ int sqlite3PagerSharedLock(Pager *pPager);
  int sqlite3PagerCheckpoint(Pager *pPager, sqlite3*, int, int*, int*);
  int sqlite3PagerWalSupported(Pager *pPager);
  int sqlite3PagerWalCallback(Pager *pPager);
-  int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
+  int sqlite3PagerOpenWal(Pager *pPager, int, int *pisOpen);
  int sqlite3PagerCloseWal(Pager *pPager, sqlite3*);
 # ifdef SQLITE_ENABLE_SNAPSHOT
  int sqlite3PagerSnapshotGet(Pager*, sqlite3_snapshot **ppSnapshot);
@@ -262,7 +262,7 @@ const char *sqlite3JournalModename(int eMode){
  static char * const azModeName[] = {
    "delete", "persist", "off", "truncate", "memory"
 #ifndef SQLITE_OMIT_WAL
-     , "wal"
+     , "wal", "wal2"
 #endif
  };
  assert( PAGER_JOURNALMODE_DELETE==0 );
@@ -271,6 +271,7 @@ const char *sqlite3JournalModename(int eMode){
  assert( PAGER_JOURNALMODE_TRUNCATE==3 );
  assert( PAGER_JOURNALMODE_MEMORY==4 );
  assert( PAGER_JOURNALMODE_WAL==5 );
+  assert( PAGER_JOURNALMODE_WAL2==6 );
  assert( eMode>=0 && eMode<=ArraySize(azModeName) );

  if( eMode==ArraySize(azModeName) ) return 0;
@@ -5301,12 +5301,12 @@ static int disableUnusedSubqueryResultColumns(SrcItem *pItem){
  assert( pItem->pSelect!=0 );
  pSub = pItem->pSelect;
  assert( pSub->pEList->nExpr==pTab->nCol );
-  if( (pSub->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){
-    testcase( pSub->selFlags & SF_Distinct );
-    testcase( pSub->selFlags & SF_Aggregate );
-    return 0;
-  }
  for(pX=pSub; pX; pX=pX->pPrior){
+    if( (pX->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){
+      testcase( pX->selFlags & SF_Distinct );
+      testcase( pX->selFlags & SF_Aggregate );
+      return 0;
+    }
    if( pX->pPrior && pX->op!=TK_ALL ){
      /* This optimization does not work for compound subqueries that
      ** use UNION, INTERSECT, or EXCEPT.  Only UNION ALL is allowed. */
@@ -190,7 +190,7 @@ static int SQLITE_TCLAPI hexio_write(
 }

 /*
-** USAGE:   hexio_get_int   HEXDATA
+** USAGE:   hexio_get_int [-littleendian] HEXDATA
 **
 ** Interpret the HEXDATA argument as a big-endian integer.  Return
 ** the value of that integer.  HEXDATA can contain between 2 and 8
@@ -207,12 +207,20 @@ static int SQLITE_TCLAPI hexio_get_int(
  const unsigned char *zIn;
  unsigned char *aOut;
  unsigned char aNum[4];
+  int bLittle = 0;

-  if( objc!=2 ){
-    Tcl_WrongNumArgs(interp, 1, objv, "HEXDATA");
+  if( objc==3 ){
+    int n;
+    char *z = Tcl_GetStringFromObj(objv[1], &n);
+    if( n>=2 && n<=13 && memcmp(z, "-littleendian", n)==0 ){
+      bLittle = 1;
+    }
+  }
+  if( (objc-bLittle)!=2 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "[-littleendian] HEXDATA");
    return TCL_ERROR;
  }
-  zIn = (const unsigned char *)Tcl_GetStringFromObj(objv[1], &nIn);
+  zIn = (const unsigned char *)Tcl_GetStringFromObj(objv[1+bLittle], &nIn);
  aOut = sqlite3_malloc( 1 + nIn/2 );
  if( aOut==0 ){
    return TCL_ERROR;
@@ -225,7 +233,11 @@ static int SQLITE_TCLAPI hexio_get_int(
    memcpy(&aNum[4-nOut], aOut, nOut);
  }
  sqlite3_free(aOut);
-  val = (aNum[0]<<24) | (aNum[1]<<16) | (aNum[2]<<8) | aNum[3];
+  if( bLittle ){
+    val = (aNum[3]<<24) | (aNum[2]<<16) | (aNum[1]<<8) | aNum[0];
+  }else{
+    val = (aNum[0]<<24) | (aNum[1]<<16) | (aNum[2]<<8) | aNum[3];
+  }
  Tcl_SetObjResult(interp, Tcl_NewIntObj(val));
  return TCL_OK;
 }
@@ -98,6 +98,7 @@ const char *sqlite3TestInit(Tcl_Interp *interp){
  extern int Fts5tcl_Init(Tcl_Interp *);
  extern int SqliteRbu_Init(Tcl_Interp*);
  extern int Sqlitetesttcl_Init(Tcl_Interp*);
+  extern int Bgckpt_Init(Tcl_Interp*);
 #if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
  extern int Sqlitetestfts3_Init(Tcl_Interp *interp);
 #endif
@@ -167,6 +168,8 @@ const char *sqlite3TestInit(Tcl_Interp *interp){
  Fts5tcl_Init(interp);
  SqliteRbu_Init(interp);
  Sqlitetesttcl_Init(interp);
+  Bgckpt_Init(interp);
+

 #if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
  Sqlitetestfts3_Init(interp);
@@ -7803,6 +7803,7 @@ case OP_JournalMode: {    /* out2 */
       || eNew==PAGER_JOURNALMODE_OFF
       || eNew==PAGER_JOURNALMODE_MEMORY
       || eNew==PAGER_JOURNALMODE_WAL
+       || eNew==PAGER_JOURNALMODE_WAL2
       || eNew==PAGER_JOURNALMODE_QUERY
  );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
@@ -7821,16 +7822,25 @@ case OP_JournalMode: {    /* out2 */
  /* Do not allow a transition to journal_mode=WAL for a database
  ** in temporary storage or if the VFS does not support shared memory
  */
-  if( eNew==PAGER_JOURNALMODE_WAL
+  if( isWalMode(eNew)
   && (sqlite3Strlen30(zFilename)==0           /* Temp file */
       || !sqlite3PagerWalSupported(pPager))   /* No shared-memory support */
  ){
    eNew = eOld;
  }

-  if( (eNew!=eOld)
-   && (eOld==PAGER_JOURNALMODE_WAL || eNew==PAGER_JOURNALMODE_WAL)
-  ){
+  if( eNew!=eOld && (isWalMode(eNew) || isWalMode(eOld)) ){
+
+    /* Prevent changing directly to wal2 from wal mode. And vice versa. */
+    if( isWalMode(eNew) && isWalMode(eOld) ){
+      rc = SQLITE_ERROR;
+      sqlite3VdbeError(p, "cannot change from %s to %s mode",
+          sqlite3JournalModename(eOld), sqlite3JournalModename(eNew)
+      );
+      goto abort_due_to_error;
+    }
+
+    /* Prevent switching into or out of wal/wal2 mode mid-transaction */
    if( !db->autoCommit || db->nVdbeRead>1 ){
      rc = SQLITE_ERROR;
      sqlite3VdbeError(p,
@@ -7838,31 +7848,34 @@ case OP_JournalMode: {    /* out2 */
          (eNew==PAGER_JOURNALMODE_WAL ? "into" : "out of")
      );
      goto abort_due_to_error;
-    }else{
-
-      if( eOld==PAGER_JOURNALMODE_WAL ){
-        /* If leaving WAL mode, close the log file. If successful, the call
-        ** to PagerCloseWal() checkpoints and deletes the write-ahead-log
-        ** file. An EXCLUSIVE lock may still be held on the database file
-        ** after a successful return.
-        */
-        rc = sqlite3PagerCloseWal(pPager, db);
-        if( rc==SQLITE_OK ){
-          sqlite3PagerSetJournalMode(pPager, eNew);
-        }
-      }else if( eOld==PAGER_JOURNALMODE_MEMORY ){
-        /* Cannot transition directly from MEMORY to WAL.  Use mode OFF
-        ** as an intermediate */
-        sqlite3PagerSetJournalMode(pPager, PAGER_JOURNALMODE_OFF);
-      }
+    }
 
-      /* Open a transaction on the database file. Regardless of the journal
-      ** mode, this transaction always uses a rollback journal.
+    if( isWalMode(eOld) ){
+      /* If leaving WAL mode, close the log file. If successful, the call
+      ** to PagerCloseWal() checkpoints and deletes the write-ahead-log 
+      ** file. An EXCLUSIVE lock may still be held on the database file 
+      ** after a successful return. 
      */
-      assert( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_WRITE );
+      rc = sqlite3PagerCloseWal(pPager, db);
      if( rc==SQLITE_OK ){
-        rc = sqlite3BtreeSetVersion(pBt, (eNew==PAGER_JOURNALMODE_WAL ? 2 : 1));
+        sqlite3PagerSetJournalMode(pPager, eNew);
      }
+    }else if( eOld==PAGER_JOURNALMODE_MEMORY ){
+      /* Cannot transition directly from MEMORY to WAL.  Use mode OFF
+      ** as an intermediate */
+      sqlite3PagerSetJournalMode(pPager, PAGER_JOURNALMODE_OFF);
+    }
+
+    /* Open a transaction on the database file. Regardless of the journal
+    ** mode, this transaction always uses a rollback journal.
+    */
+    assert( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_WRITE );
+    if( rc==SQLITE_OK ){
+      /* 1==rollback, 2==wal, 3==wal2 */
+      rc = sqlite3BtreeSetVersion(pBt, 
+          1 + isWalMode(eNew) + (eNew==PAGER_JOURNALMODE_WAL2)
+      );
+
    }
  }
 #endif /* ifndef SQLITE_OMIT_WAL */
@@ -2912,7 +2912,8 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
        /* OFF       */ 0,
        /* TRUNCATE  */ 1,
        /* MEMORY    */ 0,
-        /* WAL       */ 0
+        /* WAL       */ 0,
+        /* WAL2      */ 0
      };
      Pager *pPager;   /* Pager associated with pBt */
      needXcommit = 1;
@@ -26,7 +26,7 @@
 #define CKPT_SYNC_FLAGS(X)  (((X)>>2)&0x03)

 #ifdef SQLITE_OMIT_WAL
-# define sqlite3WalOpen(x,y,z)                   0
+# define sqlite3WalOpen(w,x,y,z)                 0
 # define sqlite3WalLimit(x,y)
 # define sqlite3WalClose(v,w,x,y,z)              0
 # define sqlite3WalBeginReadTransaction(y,z)     0
@@ -45,6 +45,7 @@
 # define sqlite3WalFramesize(z)                  0
 # define sqlite3WalFindFrame(x,y,z)              0
 # define sqlite3WalFile(x)                       0
+# define sqlite3WalJournalMode(x)                0
 # undef SQLITE_USE_SEH
 #else

@@ -56,7 +57,7 @@
 typedef struct Wal Wal;

 /* Open and close a connection to a write-ahead log. */
-int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *, int, i64, Wal**);
+int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *,int,i64,int,Wal**);
 int sqlite3WalClose(Wal *pWal, sqlite3*, int sync_flags, int, u8 *);

 /* Set the limiting size of a WAL file. */
@@ -147,6 +148,9 @@ int sqlite3WalFramesize(Wal *pWal);
 /* Return the sqlite3_file object for the WAL file */
 sqlite3_file *sqlite3WalFile(Wal *pWal);

+/* Return the journal mode (WAL or WAL2) used by this Wal object. */
+int sqlite3WalJournalMode(Wal *pWal);
+
 #ifdef SQLITE_ENABLE_SETLK_TIMEOUT
 int sqlite3WalWriteLock(Wal *pWal, int bLock);
 void sqlite3WalDb(Wal *pWal, sqlite3 *db);
@@ -47,7 +47,7 @@ db close
 forcecopy test.db test.db-template

 set unreadable_version 02
-ifcapable wal { set unreadable_version 03 }
+ifcapable wal { set unreadable_version 04 }
 do_test corruptA-2.1 {
  forcecopy test.db-template test.db
  hexio_write test.db 19 $unreadable_version   ;# the read format number
@@ -1545,4 +1545,12 @@ do_catchsql_test func-37.120 {
  SELECT sum(x) FROM c;
 } {1 {integer overflow}}

+# 2023-08-28 forum post https://sqlite.org/forum/forumpost/1c06ddcacc86032a
+# Incorrect handling of infinity by SUM().
+#
+do_execsql_test func-38.100 {
+  WITH t1(x) AS (VALUES(9e+999)) SELECT sum(x), avg(x), total(x) FROM t1;
+  WITH t1(x) AS (VALUES(-9e+999)) SELECT sum(x), avg(x), total(x) FROM t1;
+} {Inf Inf Inf -Inf -Inf -Inf}
+
 finish_test
@@ -48,6 +48,9 @@ do_execsql_test json102-180 {
 do_execsql_test json102-190 {
  SELECT json_array_length('[1,2,3,4]');
 } {{4}}
+do_execsql_test json102-191 {
+  SELECT json_array_length( json_remove('[1,2,3,4]','$[2]') );
+} {{3}}
 do_execsql_test json102-200 {
  SELECT json_array_length('[1,2,3,4]', '$');
 } {{4}}
@@ -464,18 +464,21 @@ lappend ::testsuitelist xxx
 test_suite "coverage-wal" -description {
  Coverage tests for file wal.c.
 } -files {
-  wal.test wal2.test wal3.test wal4.test wal5.test
+  wal2big.test wal2recover.test wal2rewrite.test
+  wal2simple.test wal2snapshot.test wal2.test
+  wal3.test wal4.test wal5.test
  wal64k.test wal6.test wal7.test wal8.test wal9.test
-  walbak.test walbig.test walblock.test walcksum.test walcrash2.test
-  walcrash3.test walcrash4.test walcrash.test walfault.test walhook.test
-  walmode.test walnoshm.test waloverwrite.test walpersist.test 
-  walprotocol2.test walprotocol.test walro2.test walrofault.test 
-  walro.test walshared.test walslow.test walvfs.test
-  walfault2.test
-  nockpt.test
-
+  walbak.test walbig.test walblock.test walcksum.test 
+  walfault.test walhook.test walmode.test walnoshm.test
+  waloverwrite.test walpersist.test walprotocol2.test
+  walprotocol.test walro2.test walrofault.test walro.test
+  walshared.test walslow.test wal.test
+  wal2savepoint.test wal2lock.test wal2recover2.test
+  walvfs.test walfault2.test nockpt.test
  snapshot2.test snapshot3.test snapshot4.test
  snapshot_fault.test snapshot.test snapshot_up.test
+  walcrash2.test walcrash3.test walcrash4.test walcrash.test
+  wal2fault.test
 } 

 test_suite "coverage-pager" -description {
@@ -1033,6 +1036,23 @@ test_suite "wal" -description {
  fts3c.test   fts3d.test   fts3e.test   fts3query.test 
 }

+test_suite "wal2" -description {
+  Run tests with journal_mode=WAL2
+} -initialize {
+  set ::G(savepoint6_iterations) 100
+} -shutdown {
+  unset -nocomplain ::G(savepoint6_iterations)
+} -files {
+  savepoint.test     savepoint2.test     savepoint6.test
+  trans.test         avtrans.test
+
+  fts3aa.test  fts3ab.test  fts3ac.test  fts3ad.test
+  fts3ae.test  fts3af.test  fts3ag.test  fts3ah.test
+  fts3ai.test  fts3aj.test  fts3ak.test  fts3al.test
+  fts3am.test  fts3an.test  fts3ao.test  fts3b.test
+  fts3c.test   fts3d.test   fts3e.test   fts3query.test 
+}
+
 test_suite "rtree" -description {
  All R-tree related tests. Provides coverage of source file rtree.c.
 } -files [glob -nocomplain $::testdir/../ext/rtree/*.test]
@@ -41,7 +41,7 @@ do_test rdonly-1.1.1 {
  sqlite3_db_readonly db main
 } {0}

-# Changes the write version from 1 to 3.  Verify that the database
+# Changes the write version from 1 to 4.  Verify that the database
 # can be read but not written.
 #
 do_test rdonly-1.2 {
@@ -49,7 +49,7 @@ do_test rdonly-1.2 {
  hexio_get_int [hexio_read test.db 18 1]
 } 1
 do_test rdonly-1.3 {
-  hexio_write test.db 18 03
+  hexio_write test.db 18 04
  sqlite3 db test.db
  execsql {
    SELECT * FROM t1;
@@ -83,7 +83,7 @@ do_test rdonly-1.5 {
 # the database is read-only until after it is locked.
 #
 set ro_version 02
-ifcapable wal { set ro_version 03 }
+ifcapable wal { set ro_version 04 }
 do_test rdonly-1.6 {
  hexio_write test.db 18 $ro_version     ; # write-version
  hexio_write test.db 24 11223344        ; # change-counter
@@ -30,6 +30,7 @@ do_test savepoint-1.1 {
    RELEASE sp1;
  }
 } {}
+wal_check_journal_mode savepoint-1.1
 do_test savepoint-1.2 {
  execsql {
    SAVEPOINT sp1;
@@ -807,7 +808,8 @@ do_test savepoint-11.6 {
 integrity_check savepoint-11.7
 do_test savepoint-11.8 {
  execsql { ROLLBACK }
-  execsql { PRAGMA wal_checkpoint }
+  db close
+  sqlite3 db test.db
  file size test.db
 } {8192}

@@ -15,6 +15,10 @@ set testdir [file dirname $argv0]
 source $testdir/tester.tcl

 proc sql {zSql} {
+  if {0 && $::debug_op} {
+    puts stderr "$zSql ;"
+    flush stderr
+  }
  uplevel db eval [list $zSql]
  #puts stderr "$zSql ;"
 }
@@ -67,11 +71,13 @@ proc x_to_y {x} {
 #   delete_rows XVALUES
 #
 proc savepoint {zName} {
+  if {$::debug_op} { puts stderr "savepoint $zName" ; flush stderr }
  catch { sql "SAVEPOINT $zName" }
  lappend ::lSavepoint [list $zName [array get ::aEntry]]
 }

 proc rollback {zName} {
+  if {$::debug_op} { puts stderr "rollback $zName" ; flush stderr }
  catch { sql "ROLLBACK TO $zName" }
  for {set i [expr {[llength $::lSavepoint]-1}]} {$i>=0} {incr i -1} {
    set zSavepoint [lindex $::lSavepoint $i 0]
@@ -89,6 +95,7 @@ proc rollback {zName} {
 }

 proc release {zName} {
+  if {$::debug_op} { puts stderr "release $zName" ; flush stderr }
  catch { sql "RELEASE $zName" }
  for {set i [expr {[llength $::lSavepoint]-1}]} {$i>=0} {incr i -1} {
    set zSavepoint [lindex $::lSavepoint $i 0]
@@ -104,6 +111,7 @@ proc release {zName} {
 }

 proc insert_rows {lX} {
+  if {$::debug_op} { puts stderr "insert_rows $lX" ; flush stderr }
  foreach x $lX {
    set y [x_to_y $x]

@@ -116,6 +124,7 @@ proc insert_rows {lX} {
 }

 proc delete_rows {lX} {
+  if {$::debug_op} { puts stderr "delete_rows $lX" ; flush stderr }
  foreach x $lX {
    # Update database [db]
    sql "DELETE FROM t1 WHERE x = $x"
@@ -164,6 +173,11 @@ proc random_integers {nRes nRange} {
 } 
 #-------------------------------------------------------------------------

+set ::debug_op 0
+proc debug_ops {} {
+  set ::debug_op 1
+}
+
 proc database_op {} {
  set i [expr int(rand()*2)] 
  if {$i==0} {
@@ -185,9 +199,6 @@ proc savepoint_op {} {
  set C [lindex $cmds [expr int(rand()*6)]]
  set N [lindex $names [expr int(rand()*5)]]

-  #puts stderr "   $C $N ;  "
-  #flush stderr
-
  $C $N
  return ok
 }
@@ -113,6 +113,33 @@ do_execsql_test 4.1 {
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b TEXT);
  SELECT 1 FROM (SELECT DISTINCT name COLLATE rtrim FROM sqlite_schema
                 UNION ALL SELECT a FROM t1);
-} 1
+} {1 1}
+
+do_execsql_test 4.2 {
+  SELECT DISTINCT name COLLATE rtrim FROM sqlite_schema 
+    UNION ALL 
+  SELECT a FROM t1
+} {v1 t1}
+
+#-------------------------------------------------------------------------
+# forum post https://sqlite.org/forum/forumpost/b83c7b2168
+#
+reset_db
+do_execsql_test 5.0 {
+  CREATE TABLE t1 (val1);
+  INSERT INTO t1 VALUES(4);
+  INSERT INTO t1 VALUES(5);
+  CREATE TABLE t2 (val2);
+}
+do_execsql_test 5.1 {
+  SELECT DISTINCT val1 FROM t1 UNION ALL SELECT val2 FROM t2;
+} {
+  4 5
+}
+do_execsql_test 5.2 {
+  SELECT count(1234) FROM (
+    SELECT DISTINCT val1 FROM t1 UNION ALL SELECT val2 FROM t2
+  )
+} {2}

 finish_test
@@ -613,6 +613,7 @@ proc reset_db {} {
  forcedelete test.db
  forcedelete test.db-journal
  forcedelete test.db-wal
+  forcedelete test.db-wal2
  sqlite3 db ./test.db
  set ::DB [sqlite3_connection_pointer db]
  if {[info exists ::SETUP_SQL]} {
@@ -2317,17 +2318,32 @@ proc drop_all_indexes {{db db}} {
 #     Returns true if this test should be run in WAL mode. False otherwise.
 #
 proc wal_is_wal_mode {} {
-  expr {[permutation] eq "wal"}
+  if {[permutation] eq "wal"} { return 1 }
+  if {[permutation] eq "wal2"} { return 2 }
+  return 0
 }
 proc wal_set_journal_mode {{db db}} {
-  if { [wal_is_wal_mode] } {
-    $db eval "PRAGMA journal_mode = WAL"
+  switch -- [wal_is_wal_mode] {
+    0 {
+    }
+
+    1 {
+      $db eval "PRAGMA journal_mode = WAL"
+    }
+
+    2 {
+      $db eval "PRAGMA journal_mode = WAL2"
+    }
  }
 }
 proc wal_check_journal_mode {testname {db db}} {
  if { [wal_is_wal_mode] } {
    $db eval { SELECT * FROM sqlite_master }
-    do_test $testname [list $db eval "PRAGMA main.journal_mode"] {wal}
+    set expected "wal"
+    if {[wal_is_wal_mode]==2} {
+      set expected "wal2"
+    }
+    do_test $testname [list $db eval "PRAGMA main.journal_mode"] $expected
  }
 }

@@ -98,7 +98,10 @@ namespace eval trd {
  set build(All-O0) {
    -O0 --enable-all
  }
-  set build(All-Sanitize) { --enable-all -fsanitize=address,undefined }
+  set build(All-Sanitize) { 
+    -DSQLITE_OMIT_LOOKASIDE=1
+    --enable-all -fsanitize=address,undefined 
+  }

  set build(Sanitize) {
    CC=clang -fsanitize=address,undefined
@@ -282,11 +282,11 @@ ifcapable wal {
      INSERT INTO t2 VALUES('x', 'y');
    }
    lsort [array names ::T1]
-  } {test.db1 test.db1-journal test.db1-wal}
+  } {test.db1 test.db1-journal test.db1-wal test.db1-wal2}
  
  do_test 5.1.2 {
    lsort [array names ::T2]
-  } {test.db2 test.db2-journal test.db2-wal}
+  } {test.db2 test.db2-journal test.db2-wal test.db2-wal2}
  db close
  
  tvfs1 delete
@@ -1175,7 +1175,7 @@ foreach {tn pgsz works} {
  9  32768    1
 10  65536    1
 11 131072    0
- 11   1016    0
+ 12   1016    0
 } {

  if {$::SQLITE_MAX_PAGE_SIZE < $pgsz} {
@@ -1185,14 +1185,14 @@ foreach {tn pgsz works} {
  for {set pg 1} {$pg <= 3} {incr pg} {
    forcecopy testX.db test.db
    forcedelete test.db-wal
-  
+
    # Check that the database now exists and consists of three pages. And
    # that there is no associated wal file.
    #
    do_test wal-18.2.$tn.$pg.1 { file exists test.db-wal } 0
    do_test wal-18.2.$tn.$pg.2 { file exists test.db } 1
    do_test wal-18.2.$tn.$pg.3 { file size test.db } [expr 1024*3]
-  
+
    do_test wal-18.2.$tn.$pg.4 {

      # Create a wal file that contains a single frame (database page
@@ -1224,16 +1224,16 @@ foreach {tn pgsz works} {
      puts -nonewline $fd $framehdr
      puts -nonewline $fd $framebody
      close $fd
-  
+
      file size test.db-wal
    } [wal_file_size 1 $pgsz]
-  
+
    do_test wal-18.2.$tn.$pg.5 {
      sqlite3 db test.db
      set rc [catch { db one {PRAGMA integrity_check} } msg]
      expr { $rc!=0 || $msg!="ok" }
    } $works
-  
+ 
    db close
  }
 }
@@ -0,0 +1,73 @@
+# 2017 September 19
+#
+# 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.
+#
+#***********************************************************************
+# TESTRUNNER: slow
+#
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2big
+ifcapable !wal {finish_test ; return }
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(a, b, c);
+  CREATE INDEX t1a ON t1(a);
+  CREATE INDEX t1b ON t1(b);
+  CREATE INDEX t1c ON t1(c);
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 10000000;
+
+  WITH s(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<200000
+  )
+  INSERT INTO t1 SELECT random(), random(), random() FROM s;
+} {wal2 10000000}
+
+do_execsql_test 1.1 {
+  WITH s(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<200000
+  )
+  INSERT INTO t1 SELECT random(), random(), random() FROM s;
+}
+
+do_test 1.2 {
+  list [expr [file size test.db-wal]>10000000] \
+       [expr [file size test.db-wal2]>10000000]
+} {1 1}
+
+do_test 1.3 {
+  sqlite3 db2 test.db
+  execsql {
+    SELECT count(*) FROM t1;
+    PRAGMA integrity_check;
+  } db2
+} {400000 ok}
+
+do_test 1.4 {
+  db2 close
+  forcecopy test.db test.db2
+  forcecopy test.db-wal test.db2-wal
+  forcecopy test.db-wal2 test.db2-wal2
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT count(*) FROM t1;
+    PRAGMA integrity_check;
+  }
+} {400000 ok}
+
+finish_test
@@ -0,0 +1,52 @@
+# 2010 May 03
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/malloc_common.tcl
+source $testdir/lock_common.tcl
+
+ifcapable !wal {finish_test ; return }
+set testprefix wal2fault
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(x,y);
+  PRAGMA journal_mode = wal2;
+  WITH s(i) AS ( SELECT 100 UNION ALL SELECT i-1 FROM s WHERE (i-1)>0 )
+  INSERT INTO t1 SELECT i, randomblob(i) FROM s;
+  WITH s(i) AS ( SELECT 100 UNION ALL SELECT i-1 FROM s WHERE (i-1)>0 )
+  INSERT INTO t1 SELECT i, randomblob(i) FROM s;
+} {wal2}
+
+do_test 1.1 {
+  expr [file size test.db-wal]>10000
+} {1}
+faultsim_save_and_close
+
+do_faultsim_test 1 -prep {
+  faultsim_restore_and_reopen
+  execsql {
+    PRAGMA journal_size_limit = 10000;
+    SELECT count(*) FROM sqlite_master;
+  }
+} -body {
+  execsql {
+    INSERT INTO t1 VALUES(1, 2);
+  }
+} -test {
+  faultsim_test_result {0 {}}
+}
+
+finish_test
@@ -0,0 +1,106 @@
+# 2018 December 15
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2lock
+ifcapable !wal {finish_test ; return }
+
+db close
+testvfs tvfs 
+sqlite3 db test.db -vfs tvfs
+
+do_execsql_test 1.0 {
+  PRAGMA journal_mode = wal2;
+  CREATE TABLE y1(y, yy);
+  CREATE INDEX y1y ON y1(y);
+  CREATE INDEX y1yy ON y1(yy);
+  INSERT INTO y1 VALUES(1, 2), (3, 4), (5, 6);
+} {wal2}
+
+tvfs script vfs_callback
+tvfs filter xShmLock
+
+set ::lock [list]
+proc vfs_callback {func file name lock} {
+  lappend ::lock $lock
+  return SQLITE_OK
+}
+
+do_execsql_test 1.1.1 {
+  SELECT * FROM y1
+} {1 2 3 4 5 6}
+do_test 1.1.2 {
+  set ::lock
+} {{4 1 lock shared} {4 1 unlock shared}}
+
+set ::bFirst 1
+proc vfs_callback {func file name lock} {
+  if {$::bFirst} {
+    set ::bFirst 0
+    return SQLITE_BUSY
+  }
+  return SQLITE_OK
+}
+do_execsql_test 1.2 {
+  SELECT * FROM y1
+} {1 2 3 4 5 6}
+
+set ::bFirst 1
+proc vfs_callback {func file name lock} {
+  if {$::bFirst} {
+    set ::bFirst 0
+    return SQLITE_IOERR
+  }
+  return SQLITE_OK
+}
+do_catchsql_test 1.3 {
+  SELECT * FROM y1
+} {1 {disk I/O error}}
+
+puts "# Warning: This next test case causes SQLite to call xSleep(1) 100 times."
+puts "# Normally this equates to a delay of roughly 10 seconds, but if SQLite"
+puts "# is built on unix without HAVE_USLEEP defined, it may be much longer."
+proc vfs_callback {func file name lock} { return SQLITE_BUSY }
+do_catchsql_test 1.4 {
+  SELECT * FROM y1
+} {1 {locking protocol}}
+proc vfs_callback {func file name lock} { return SQLITE_OK }
+
+sqlite3 db2 test.db -vfs tvfs
+set ::bFirst 1
+
+proc vfs_callback {func file name lock} {
+  if {$::bFirst} {
+    set ::bFirst 0
+    db2 eval { INSERT INTO y1 VALUES(7, 8) }
+  }
+}
+
+do_execsql_test 1.5.1 {
+  SELECT * FROM y1
+} {1 2 3 4 5 6 7 8}
+do_execsql_test 1.5.2 {
+  SELECT * FROM y1
+} {1 2 3 4 5 6 7 8}
+
+db close
+db2 close
+tvfs delete
+finish_test
@@ -0,0 +1,81 @@
+# 2017 September 19
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2openclose
+ifcapable !wal {finish_test ; return }
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(a, b, c);
+  PRAGMA journal_mode = wal2;
+  PRAGMA wal_autocheckpoint = 0;
+  PRAGMA journal_size_limit = 75000;
+} {wal2 0 75000}
+
+do_test 1.1 {
+  for {set ii 1} {$ii <= 200} {incr ii} {
+    execsql {
+      INSERT INTO t1 VALUES($ii, $ii, $ii);
+    }
+  }
+  expr ([file size test.db-wal2] - 75000) > 30000
+} {1}
+
+do_test 1.2 {
+  db close
+  list [file exists test.db-wal] [file exists test.db-wal2]
+} {0 0}
+
+sqlite3 db test.db
+do_execsql_test 1.3 {
+  SELECT sum(c) FROM t1
+} {20100}
+db close
+
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 2.0 {
+  CREATE TABLE t1(a, b, c);
+  PRAGMA journal_mode = wal2;
+  INSERT INTO t1 VALUES(1, 2, 3);
+} {wal2}
+db_save_and_close
+
+db_restore_and_reopen
+do_execsql_test 2.1 {
+  SELECT * FROM t1;
+} {1 2 3}
+
+do_test 2.2 {
+  sqlite3 db2 test.db
+  db2 eval {INSERT INTO t1 VALUES(4, 5, 6)}
+  db2 close
+} {}
+
+breakpoint
+db close
+sqlite3 db test.db
+do_execsql_test 2.2 {
+  SELECT * FROM t1;
+} {1 2 3 4 5 6}
+
+
+
+finish_test
@@ -0,0 +1,272 @@
+# 2018 December 13
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2recover
+ifcapable !wal {finish_test ; return }
+
+proc db_copy {from to} {
+  forcecopy $from $to
+  forcecopy ${from}-wal ${to}-wal
+  forcecopy ${from}-wal2 ${to}-wal2
+}
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(a, b, c);
+  CREATE INDEX t1a ON t1(a);
+  CREATE INDEX t1b ON t1(b);
+  CREATE INDEX t1c ON t1(c);
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 15000;
+  PRAGMA wal_autocheckpoint = 0;
+} {wal2 15000 0}
+
+do_test 1.1 {
+  for {set i 1} {$i <= 1000} {incr i} {
+    execsql { INSERT INTO t1 VALUES(random(), random(), random()) }
+    db_copy test.db test.db2
+    sqlite3 db2 test.db
+    set res [execsql {
+      SELECT count(*) FROM t1;
+      PRAGMA integrity_check;
+    } db2]
+    db2 close
+    if {$res != [list $i ok]} {
+      error "failure on iteration $i"
+    }
+  }
+  set {} {}
+} {}
+
+#--------------------------------------------------------------------------
+reset_db
+do_execsql_test 2.0 {
+  CREATE TABLE t1(x UNIQUE);
+  CREATE TABLE t2(x UNIQUE);
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 10000;
+  PRAGMA wal_autocheckpoint = 0;
+  BEGIN;
+    INSERT INTO t1 VALUES(randomblob(4000));
+    INSERT INTO t1 VALUES(randomblob(4000));
+    INSERT INTO t1 VALUES(randomblob(4000));
+  COMMIT;
+  BEGIN;
+    INSERT INTO t2 VALUES(randomblob(4000));
+    INSERT INTO t2 VALUES(randomblob(4000));
+    INSERT INTO t2 VALUES(randomblob(4000));
+  COMMIT;
+} {wal2 10000 0}
+do_test 2.0.1 {
+  list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
+} {5120 28328 28328}
+
+# Test recovery with both wal files intact.
+#
+do_test 2.1 {
+  db_copy test.db test.db2
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT count(*) FROM t1;
+    SELECT count(*) FROM t2;
+    PRAGMA integrity_check;
+  } db2
+} {3 3 ok}
+
+do_test 2.2 {
+  db2 close
+  db_copy test.db test.db2
+  hexio_write test.db2-wal 16 12345678
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT count(*) FROM t1;
+    SELECT count(*) FROM t2;
+  } db2
+} {0 3}
+
+do_test 2.3 {
+  db2 close
+  db_copy test.db test.db2
+  hexio_write test.db2-wal2 16 12345678
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT count(*) FROM t1;
+    SELECT count(*) FROM t2;
+    PRAGMA integrity_check;
+  } db2
+} {3 0 ok}
+
+do_test 2.4 {
+  db2 close
+  db_copy test.db test.db2
+  forcecopy test.db-wal test.db2-wal2
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT count(*) FROM t1;
+    SELECT count(*) FROM t2;
+    PRAGMA integrity_check;
+  } db2
+} {3 0 ok}
+
+do_test 2.5 {
+  db2 close
+  db_copy test.db test.db2
+  forcecopy test.db-wal  test.db2-wal2
+  forcecopy test.db-wal2  test.db2-wal
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT count(*) FROM t1;
+    SELECT count(*) FROM t2;
+    PRAGMA integrity_check;
+  } db2
+} {3 3 ok}
+
+do_test 2.6 {
+  db2 close
+  db_copy test.db test.db2
+  forcecopy test.db-wal test.db2-wal2
+  close [open test.db-wal w]
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT count(*) FROM t1;
+    SELECT count(*) FROM t2;
+    PRAGMA integrity_check;
+  } db2
+} {3 0 ok}
+
+do_test 2.7 {
+  db2 close
+  db_copy test.db test.db2
+  forcedelete test.db2-wal
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT count(*) FROM t1;
+    SELECT count(*) FROM t2;
+    PRAGMA integrity_check;
+  } db2
+} {0 0 ok}
+db2 close
+
+#-------------------------------------------------------------------------
+#
+reset_db
+do_execsql_test 3.0 {
+  CREATE TABLE t1(a TEXT, b TEXT, c TEXT);
+  CREATE INDEX t1a ON t1(a);
+  CREATE INDEX t1b ON t1(b);
+  CREATE INDEX t1c ON t1(c);
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 10000;
+  PRAGMA wal_autocheckpoint = 0;
+  PRAGMA cache_size = 5;
+} {wal2 10000 0}
+
+do_execsql_test 3.1 {
+  WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 200)
+  INSERT INTO t1 SELECT i, i, i FROM s;
+
+  INSERT INTO t1 VALUES(201, 201, 201);
+} {}
+
+do_test 3.2 {
+  list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
+} {5120 15752 4224}
+
+do_test 3.3 {
+  forcecopy test.db test.db2
+  forcecopy test.db-wal test.db2-wal
+  forcecopy test.db-wal2 test.db2-wal2
+  sqlite3 db2 test.db2
+  execsql {
+    PRAGMA journal_size_limit = 10000;
+    PRAGMA wal_autocheckpoint = 0;
+    PRAGMA cache_size = 5;
+    BEGIN;
+      WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 200)
+      INSERT INTO t1 SELECT i, i, i FROM s;
+  } db2
+  list [file size test.db2] [file size test.db2-wal] [file size test.db2-wal2]
+} {5120 15752 23088}
+
+
+if {$tcl_platform(platform)!="windows"} {
+  # These cannot be run under windows, as the *-shm file may not be read
+  # while it is locked by the database connection. 
+  do_test 3.4 {
+    set fd [open test.db2-shm]
+    fconfigure $fd -encoding binary -translation binary
+    set data [read $fd]
+    close $fd
+  
+    set fd [open test.db-shm w]
+    fconfigure $fd -encoding binary -translation binary
+    puts -nonewline $fd $data
+    close $fd
+  
+    execsql {
+      WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 10)
+        INSERT INTO t1 SELECT i, i, i FROM s;
+      SELECT count(*) FROM t1;
+      PRAGMA integrity_check;
+    }
+  } {211 ok}
+  
+  do_test 3.5 {
+    list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
+  } {5120 15752 18896}
+}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+do_execsql_test 4.0 {
+  PRAGMA journal_mode = wal2;
+  CREATE TABLE xyz(x, y, z);
+  INSERT INTO xyz VALUES('x', 'y', 'z');
+} {wal2}
+db close
+do_test 4.1 {
+  close [open test.db-wal w]
+  file mkdir test.db-wal2
+  sqlite3 db test.db
+  catchsql { SELECT * FROM xyz }
+} {1 {unable to open database file}}
+db close
+file delete test.db-wal2
+db2 close
+
+do_test 4.2 {
+  sqlite3 db test.db
+  execsql { 
+    INSERT INTO xyz VALUES('a', 'b', 'c');
+  }
+  forcecopy test.db test.db2
+  forcecopy test.db-wal test.db2-wal
+  forcedelete test.db2-wal2
+  file mkdir test.db2-wal2
+  sqlite3 db2 test.db2
+  catchsql { SELECT * FROM xyz } db2
+} {1 {unable to open database file}}
+db2 close
+file delete test.db2-wal2
+
+
+finish_test
+
@@ -0,0 +1,273 @@
+# 2018 December 13
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2recover2
+ifcapable !wal {finish_test ; return }
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(x);
+  CREATE TABLE t2(x);
+  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
+    INSERT INTO t1 SELECT i FROM s;
+  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
+    INSERT INTO t2 SELECT i FROM s;
+
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 10000;
+} {wal2 10000}
+
+set ::L 1125750
+set ::M 1126500
+set ::H 1127250
+
+do_execsql_test 1.1 {
+  UPDATE t1 SET x=x+1;
+  UPDATE t2 SET x=x+1 WHERE rowid<=750;
+
+  SELECT sum(x) FROM t1;
+  SELECT sum(x) FROM t2;
+} [list $H $M]
+
+do_test 1.2 {
+  list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
+} {31744 14704 7368}
+
+proc cksum {zIn data} {
+  if {[string length $zIn]==0} {
+    set s0 0
+    set s1 0
+  } else {
+    set s0 [hexio_get_int [string range $zIn 0 7]]
+    set s1 [hexio_get_int [string range $zIn 8 15]]
+  }
+  set n [expr [string length $data] / 8]
+
+  for {set i 0} {$i < $n} {incr i 2} {
+    set x0 [hexio_get_int -l [string range $data [expr $i*8]   [expr $i*8+7]]]
+    set x1 [hexio_get_int -l [string range $data [expr $i*8+8] [expr $i*8+8+7]]]
+
+    set s0 [expr ($s0 + $x0 + $s1) & 0xFFFFFFFF]
+    set s1 [expr ($s1 + $x1 + $s0) & 0xFFFFFFFF]
+  }
+
+  return "[hexio_render_int32 $s0][hexio_render_int32 $s1]"
+}
+
+proc fix_wal_cksums {file} {
+  # Fix the checksum on the wal header.
+  set data [hexio_read $file 0 32]
+  set cksum [cksum {} [string range $data 0 47]]
+  set salt [hexio_read $file 16 8]
+  hexio_write $file 24 $cksum
+
+  # Fix the checksums for all pages in the wal file.
+  set pgsz [hexio_get_int [hexio_read $file 8 4]]
+  set sz [file size $file]
+  for {set off 32} {$off < $sz} {incr off [expr $pgsz+24]} {
+    set e [hexio_read $file $off 8]
+    set cksum [cksum $cksum $e]
+
+    set p [hexio_read $file [expr $off+24] $pgsz]
+    set cksum [cksum $cksum $p]
+
+    hexio_write $file [expr $off+8] $salt
+    hexio_write $file [expr $off+16] $cksum
+  }
+}
+
+proc wal_incr_hdrfield {file field} {
+  switch -- $field {
+    nCkpt { set offset 12 }
+    salt0 { set offset 16 }
+    salt1 { set offset 20 }
+    default {
+      error "unknown field $field - should be \"nCkpt\", \"salt0\" or \"salt1\""
+    }
+  }
+
+  # Increment the value in the wal header.
+  set v [hexio_get_int [hexio_read $file $offset 4]]
+  incr v
+  hexio_write $file $offset [hexio_render_int32 $v]
+  
+  # Fix various checksums
+  fix_wal_cksums $file
+}
+
+proc wal_set_nckpt {file val} {
+  # Increment the value in the wal header.
+  hexio_write $file 12 [hexio_render_int32 $val]
+  
+  # Fix various checksums
+  fix_wal_cksums $file
+}
+
+proc wal_set_follow {file prevfile} {
+  set pgsz [hexio_get_int [hexio_read $prevfile 8 4]]
+  set sz [file size $prevfile]
+  set cksum [hexio_read $prevfile [expr $sz-$pgsz-8] 8]
+
+  hexio_write $file 16 $cksum
+  fix_wal_cksums $file
+}
+
+foreach {tn file field} {
+  1 test.db2-wal    salt0
+  2 test.db2-wal    salt1
+  3 test.db2-wal    nCkpt
+  4 test.db2-wal2   salt0
+  5 test.db2-wal2   salt1
+  6 test.db2-wal2   nCkpt
+} {
+  do_test 1.3.$tn {
+    forcecopy test.db test.db2
+    forcecopy test.db-wal test.db2-wal
+    forcecopy test.db-wal2 test.db2-wal2
+    wal_incr_hdrfield $file $field
+    sqlite3 db2 test.db2
+    execsql {
+      SELECT sum(x) FROM t1;
+      SELECT sum(x) FROM t2;
+    } db2
+  } [list $H $L]
+  db2 close
+}
+
+do_test 1.4 {
+  forcecopy test.db test.db2
+  forcecopy test.db-wal2 test.db2-wal
+  forcedelete test.db2-wal2
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT sum(x) FROM t1;
+    SELECT sum(x) FROM t2;
+  } db2
+} [list $L $M]
+
+do_test 1.5 {
+  db2 close
+  forcecopy test.db test.db2
+  forcecopy test.db-wal2 test.db2-wal
+  forcecopy test.db-wal test.db2-wal2
+  sqlite3 db2 test.db2
+  execsql {
+    SELECT sum(x) FROM t1;
+    SELECT sum(x) FROM t2;
+  } db2
+} [list $H $M]
+
+db2 close
+foreach {tn file field} {
+  1 test.db2-wal    salt0
+  2 test.db2-wal    salt1
+  3 test.db2-wal2   salt0
+  4 test.db2-wal2   salt1
+} {
+  do_test 1.6.$tn {
+    forcecopy test.db test.db2
+    forcecopy test.db-wal2 test.db2-wal
+    forcecopy test.db-wal test.db2-wal2
+    wal_incr_hdrfield $file $field
+    sqlite3 db2 test.db2
+    execsql {
+      SELECT sum(x) FROM t1;
+      SELECT sum(x) FROM t2;
+    } db2
+  } [list $H $L]
+  db2 close
+}
+
+foreach {tn nCkpt1 nCkpt2 res} [list \
+  1   2 1   "$H $M"                  \
+  2   2 2   "$L $M"                  \
+  3   3 1   "$H $L"                  \
+  4   15 14 "$H $M"                  \
+  5   0 15  "$H $M"                  \
+  6   1 15  "$L $M"                  \
+] {
+  do_test 1.7.$tn {
+    forcecopy test.db test.db2
+    forcecopy test.db-wal2 test.db2-wal
+    forcecopy test.db-wal test.db2-wal2
+
+    wal_set_nckpt test.db2-wal2 $nCkpt2
+    wal_set_nckpt test.db2-wal  $nCkpt1
+    wal_set_follow test.db2-wal test.db2-wal2
+
+
+    sqlite3 db2 test.db2
+    execsql {
+      SELECT sum(x) FROM t1;
+      SELECT sum(x) FROM t2;
+    } db2
+  } $res
+  db2 close
+}
+
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 1.8.1 {
+  PRAGMA autovacuum = 0;
+  PRAGMA page_size = 4096;
+  CREATE TABLE t1(x);
+  CREATE TABLE t2(x);
+  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
+    INSERT INTO t1 SELECT i FROM s;
+  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
+    INSERT INTO t2 SELECT i FROM s;
+
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 10000;
+
+  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
+    INSERT INTO t2 SELECT i FROM s;
+} {wal2 10000}
+
+do_test 1.8.2 {
+  list [file size test.db-wal] [file size test.db-wal2]
+} {24752 0}
+
+do_execsql_test 1.8.3 { PRAGMA user_version = 123 }
+do_test 1.8.4 {
+  list [file size test.db-wal] [file size test.db-wal2]
+} {24752 4152}
+
+do_test 1.8.5 {
+  hexio_write test.db-wal2 [expr 56+16] 0400
+  fix_wal_cksums test.db-wal2
+} {}
+
+ifcapable oversize_cell_check {
+  set msg {database disk image is malformed}
+} else {
+  set msg {malformed database schema (?)}
+}
+
+do_test 1.8.6 {
+  forcecopy test.db test.db2
+  forcecopy test.db-wal test.db2-wal
+  forcecopy test.db-wal2 test.db2-wal2
+  sqlite3 db2 test.db2
+  catchsql { SELECT * FROM sqlite_master } db2
+} [list 1 $msg]
+db2 close
+
+finish_test
@@ -0,0 +1,52 @@
+# 2022 June 28
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2recover3
+ifcapable !wal {finish_test ; return }
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(x);
+  CREATE TABLE t2(x);
+  PRAGMA journal_mode = wal2;
+  PRAGMA wal_autocheckpoint = 0;
+  PRAGMA journal_size_limit = 10000;
+} {wal2 0 10000}
+
+do_execsql_test 1.1 {
+  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
+    INSERT INTO t1 SELECT i FROM s;
+  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
+    INSERT INTO t2 SELECT i FROM s;
+}
+
+db_save_and_close
+set fd [open sv_test.db-wal2 r+]
+seek $fd 4000
+puts -nonewline $fd 0
+close $fd
+
+db_restore_and_reopen
+do_execsql_test 1.2 {
+  SELECT sql FROM sqlite_schema;
+} {{CREATE TABLE t1(x)} {CREATE TABLE t2(x)}}
+
+finish_test
+
@@ -0,0 +1,92 @@
+# 2017 September 19
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2rewrite
+ifcapable !wal {finish_test ; return }
+
+proc filesize {filename} {
+  if {[file exists $filename]} {
+    return [file size $filename]
+  }
+  return 0
+}
+
+foreach {tn jrnlmode} {
+  1 wal
+  2 wal2
+} {
+  reset_db
+  execsql "PRAGMA journal_mode = $jrnlmode"
+  do_execsql_test $tn.1 {
+    PRAGMA journal_size_limit = 10000;
+    PRAGMA cache_size = 5;
+    PRAGMA wal_autocheckpoint = 10;
+  
+    CREATE TABLE t1(a INTEGER PRIMARY KEY, b INTEGER, c BLOB);
+    CREATE INDEX t1b ON t1(b);
+    CREATE INDEX t1c ON t1(c);
+  
+    WITH s(i) AS (
+      SELECT 1 UNION SELECT i+1 FROM s WHERE i<10
+    )
+    INSERT INTO t1 SELECT i, i, randomblob(800) FROM s;
+  } {10000 10}
+  
+  for {set i 0} {$i < 4} {incr i} {
+    do_execsql_test $tn.$i.1 {
+      UPDATE t1 SET c=randomblob(800) WHERE (b%10)==5 AND ($i%2)
+    }
+    do_execsql_test $tn.$i.2 {
+      BEGIN;
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+      UPDATE t1 SET b=b+10, c=randomblob(800);
+    }
+    execsql COMMIT
+
+    do_test $tn.$i.3 { expr [filesize test.db-wal]  < 100000 } 1
+    do_test $tn.$i.4 { expr [filesize test.db-wal2] < 100000 } 1
+
+    set sum [db eval {SELECT sum(b), md5sum(c) FROM t1}]
+
+    do_test $tn.$i.5 {
+      foreach f [glob -nocomplain test.db2*] {forcedelete $f}
+      foreach f [glob -nocomplain test.db*] {
+        forcecopy $f [string map {test.db test.db2} $f]
+      }
+
+      sqlite3 db2 test.db2
+      db2 eval {SELECT sum(b), md5sum(c) FROM t1}
+    } $sum
+    db2 close
+  }
+}
+    
+
+
+finish_test
@@ -0,0 +1,62 @@
+# 2017 September 19
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2rollback
+ifcapable !wal {finish_test ; return }
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(a, b, c);
+  CREATE TABLE t2(a, b, c);
+  CREATE INDEX i1 ON t1(a);
+  CREATE INDEX i2 ON t1(b);
+  PRAGMA journal_mode = wal2;
+  PRAGMA cache_size = 5;
+  PRAGMA journal_size_limit = 10000;
+  WITH s(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM s LIMIT 1000
+  )
+  INSERT INTO t1 SELECT i, i, randomblob(200) FROM s;
+} {wal2 10000}
+
+do_test 1.1 {
+  expr [file size test.db-wal] > 10000
+} 1
+
+do_test 1.2 {
+  execsql {
+    BEGIN;
+      UPDATE t1 SET b=b+1;
+      INSERT INTO t2 VALUES(1,2,3);
+  }
+  expr [file size test.db-wal2] > 10000
+} {1}
+
+breakpoint
+do_execsql_test 1.3 {
+  ROLLBACK;
+  SELECT * FROM t2;
+  SELECT count(*) FROM t1 WHERE a=b;
+  PRAGMA integrity_check;
+} {1000 ok}
+
+
+
+finish_test
@@ -0,0 +1,73 @@
+# 2018 December 13
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2savepoint
+ifcapable !wal {finish_test ; return }
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(a, b, c);
+  CREATE INDEX t1a ON t1(a);
+  CREATE INDEX t1b ON t1(b);
+  CREATE INDEX t1c ON t1(c);
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 15000;
+  PRAGMA wal_autocheckpoint = 0;
+  PRAGMA cache_size = 5;
+} {wal2 15000 0}
+
+do_execsql_test 1.1 {
+  WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 200)
+  INSERT INTO t1 SELECT random(), random(), random() FROM s;
+} {}
+
+do_test 1.2 {
+  list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
+} {5120 23088 0}
+
+do_execsql_test 1.3 {
+  BEGIN;
+    SAVEPOINT abc;
+      WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 100)
+      INSERT INTO t1 SELECT random(), random(), random() FROM s;
+    ROLLBACK TO abc;
+    WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 10)
+    INSERT INTO t1 SELECT random(), random(), random() FROM s;
+  COMMIT;
+  SELECT count(*) FROM t1;
+  PRAGMA integrity_check;
+} {210 ok}
+
+do_execsql_test 1.4 {
+  BEGIN;
+    SAVEPOINT abc;
+      WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 100)
+      INSERT INTO t1 SELECT random(), random(), random() FROM s;
+    ROLLBACK TO abc;
+    WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 10)
+    INSERT INTO t1 SELECT random(), random(), random() FROM s;
+  COMMIT;
+  SELECT count(*) FROM t1;
+  PRAGMA integrity_check;
+} {220 ok}
+
+
+finish_test
+
@@ -0,0 +1,475 @@
+# 2017 September 19
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2simple
+ifcapable !wal {finish_test ; return }
+
+#-------------------------------------------------------------------------
+# The following tests verify that a client can switch in and out of wal
+# and wal2 mode. But that it is not possible to change directly from wal
+# to wal2, or from wal2 to wal mode.
+#
+do_execsql_test 1.1.0 {
+  PRAGMA journal_mode = wal2
+} {wal2}
+execsql { SELECT * FROM sqlite_master} 
+do_execsql_test 1.x {
+  PRAGMA journal_mode;
+  PRAGMA main.journal_mode;
+} {wal2 wal2}
+db close
+do_test 1.1.1 { file size test.db } {1024}
+do_test 1.1.2 { hexio_read test.db 18 2 } 0303
+
+sqlite3 db test.db
+do_execsql_test 1.2.0 {
+  SELECT * FROM sqlite_master;
+  PRAGMA journal_mode = delete;
+} {delete}
+db close
+do_test 1.2.1 { file size test.db } {1024}
+do_test 1.2.2 { hexio_read test.db 18 2 } 0101
+
+sqlite3 db test.db
+do_execsql_test 1.3.0 {
+  SELECT * FROM sqlite_master;
+  PRAGMA journal_mode = wal;
+} {wal}
+db close
+do_test 1.3.1 { file size test.db } {1024}
+do_test 1.3.2 { hexio_read test.db 18 2 } 0202
+
+sqlite3 db test.db
+do_catchsql_test 1.4.0 {
+  PRAGMA journal_mode = wal2;
+} {1 {cannot change from wal to wal2 mode}}
+do_execsql_test 1.4.1 {
+  PRAGMA journal_mode = wal;
+  PRAGMA journal_mode = delete;
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_mode = wal2;
+} {wal delete wal2 wal2}
+do_catchsql_test 1.4.2 {
+  PRAGMA journal_mode = wal;
+} {1 {cannot change from wal2 to wal mode}}
+db close
+do_test 1.4.3 { hexio_read test.db 18 2 } 0303
+
+#-------------------------------------------------------------------------
+# Test that recovery in wal2 mode works.
+#
+forcedelete test.db test.db-wal test.db-wal2
+reset_db
+do_execsql_test 2.0 {
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 5000;
+} {wal2 5000}
+
+proc wal_hook {DB nm nFrame} { $DB eval { PRAGMA wal_checkpoint } }
+db wal_hook {wal_hook db}
+
+for {set i 1} {$i <= 200} {incr i} {
+  execsql { INSERT INTO t1 VALUES(NULL, randomblob(100)) }
+  set res [db eval { SELECT sum(a), md5sum(b) FROM t1 }]
+
+  do_test 2.1.$i {
+    foreach f [glob -nocomplain test.db2*] { forcedelete $f }
+    forcecopy test.db      test.db2
+    forcecopy test.db-wal  test.db2-wal
+    forcecopy test.db-wal2 test.db2-wal2
+
+    sqlite3 db2 test.db2
+    db2 eval { SELECT sum(a), md5sum(b) FROM t1 }
+  } $res
+
+  db2 close
+}
+
+#-------------------------------------------------------------------------
+
+reset_db
+do_execsql_test 3.0 {
+  CREATE TABLE t1(x BLOB, y INTEGER PRIMARY KEY);
+  CREATE INDEX i1 ON t1(x);
+  PRAGMA cache_size = 5;
+  PRAGMA journal_mode = wal2;
+} {wal2}
+
+do_test 3.1 {
+  execsql BEGIN
+  for {set i 1} {$i < 1000} {incr i} {
+    execsql { INSERT INTO t1 VALUES(randomblob(800), $i) }
+  }
+  execsql COMMIT
+} {}
+
+do_execsql_test 3.2 {
+  PRAGMA integrity_check;
+} {ok}
+
+#-------------------------------------------------------------------------
+catch { db close }
+foreach f [glob -nocomplain test.db*] { forcedelete $f }
+reset_db
+do_execsql_test 4.0 {
+  CREATE TABLE t1(x, y);
+  PRAGMA journal_mode = wal2;
+} {wal2}
+
+do_execsql_test 4.1 {
+  SELECT * FROM t1;
+} {}
+
+do_execsql_test 4.2 {
+  INSERT INTO t1 VALUES(1, 2);
+} {}
+
+do_execsql_test 4.3 {
+  SELECT * FROM t1;
+} {1 2}
+
+do_test 4.4 {
+  sqlite3 db2 test.db
+  execsql { SELECT * FROM t1 } db2
+} {1 2}
+
+do_test 4.5 {
+  lsort [glob test.db*]
+} {test.db test.db-shm test.db-wal test.db-wal2}
+
+do_test 4.6 {
+  db close
+  db2 close
+  sqlite3 db test.db
+  execsql { SELECT * FROM t1 }
+} {1 2}
+
+do_execsql_test 4.7 {
+  PRAGMA journal_size_limit = 4000;
+  INSERT INTO t1 VALUES(3, 4);
+  INSERT INTO t1 VALUES(5, 6);
+  INSERT INTO t1 VALUES(7, 8);
+  INSERT INTO t1 VALUES(9, 10);
+  INSERT INTO t1 VALUES(11, 12);
+  INSERT INTO t1 VALUES(13, 14);
+  INSERT INTO t1 VALUES(15, 16);
+  INSERT INTO t1 VALUES(17, 18);
+  SELECT * FROM t1;
+} {4000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18}
+
+do_test 4.8 {
+  sqlite3 db2 test.db
+  execsql { SELECT * FROM t1 } db2
+} {1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18}
+
+do_test 4.9 {
+  db close
+  db2 close
+  lsort [glob test.db*]
+} {test.db}
+
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 5.0 {
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c);
+  CREATE INDEX i1 ON t1(b, c);
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 4000;
+} {wal2 4000}
+
+proc wal_hook {DB nm nFrame} {
+  $DB eval { PRAGMA wal_checkpoint }
+}
+db wal_hook [list wal_hook db]
+
+
+foreach js {4000 8000 12000} {
+  foreach NROW [list 100 200 300 400 500 600 1000] {
+    do_test 5.$js.$NROW.1 {
+      db eval "DELETE FROM t1"
+      db eval "PRAGMA journal_size_limit = $js"
+      set nTotal 0
+      for {set i 0} {$i < $NROW} {incr i} {
+        db eval { INSERT INTO t1 VALUES($i, $i, randomblob(abs(random()%50))) }
+        incr nTotal $i
+      }
+      set {} {}
+    } {}
+
+    do_test 5.$js.$NROW.2 {
+      sqlite3 db2 test.db
+      db2 eval { 
+        PRAGMA integrity_check;
+        SELECT count(*), sum(b) FROM t1;
+      }
+    } [list ok $NROW $nTotal]
+
+    db2 close
+  }
+}
+
+
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 6.0 {
+  CREATE TABLE tx(x);
+  PRAGMA journal_mode = wal2;
+  PRAGMA journal_size_limit = 3500;
+} {wal2 3500}
+
+do_test 6.1 {
+  for {set i 0} {$i < 10} {incr i} {
+    execsql "CREATE TABLE t$i (x);"
+  }
+} {}
+
+do_test 6.2.1 {
+  foreach f [glob -nocomplain test.db2*] { forcedelete $f }
+  forcecopy test.db-wal2 test.db2-wal2
+  sqlite3 db2 test.db2
+  db2 eval { SELECT * FROM sqlite_master }
+} {}
+do_test 6.2.2 {
+  db2 eval {
+    PRAGMA journal_mode = wal2;
+    SELECT * FROM sqlite_master;
+  }
+} {wal2}
+
+do_test 6.3.1 {
+  db2 close
+  foreach f [glob -nocomplain test.db2*] { forcedelete $f }
+  forcecopy test.db-wal2 test.db2-wal2
+  forcecopy test.db test.db2
+  sqlite3 db2 test.db2
+  db2 eval { SELECT * FROM sqlite_master }
+} {table tx tx 2 {CREATE TABLE tx(x)}}
+do_test 6.3.2 {
+  db2 eval {
+    PRAGMA journal_mode = wal2;
+    SELECT * FROM sqlite_master;
+  }
+} {wal2 table tx tx 2 {CREATE TABLE tx(x)}}
+
+do_test 6.4.1 {
+  db2 close
+  foreach f [glob -nocomplain test.db2*] { forcedelete $f }
+  forcecopy test.db-wal2 test.db2-wal2
+  forcecopy test.db-wal test.db2-wal
+  sqlite3 db2 test.db2
+  db2 eval { SELECT * FROM sqlite_master }
+} {}
+do_test 6.4.2 {
+  db2 eval {
+    PRAGMA journal_mode = wal2;
+    SELECT * FROM sqlite_master;
+  }
+} {wal2}
+db2 close
+
+#-------------------------------------------------------------------------
+reset_db
+sqlite3 db2 test.db
+do_execsql_test 7.0 {
+  PRAGMA journal_size_limit = 10000;
+  PRAGMA journal_mode = wal2;
+  PRAGMA wal_autocheckpoint = 0;
+  BEGIN;
+    CREATE TABLE t1(a);
+    INSERT INTO t1 VALUES( randomblob(8000) );
+  COMMIT;
+} {10000 wal2 0}
+
+do_test 7.1 {
+  list [file size test.db-wal] [file size test.db-wal2]
+} {9464 0}
+
+# Connection db2 is holding a PART1 lock. 
+#
+#   7.2.2: Test that the PART1 does not prevent db from switching to the
+#          other wal file.
+#
+#   7.2.3: Test that the PART1 does prevent a checkpoint of test.db-wal.
+#
+#   7.2.4: Test that after the PART1 is released the checkpoint is possible.
+#
+do_test 7.2.1 {
+  execsql {
+    BEGIN;
+      SELECT count(*) FROM t1;
+  } db2
+} {1}
+do_test 7.2.2 {
+  execsql {
+    INSERT INTO t1 VALUES( randomblob(800) );
+    INSERT INTO t1 VALUES( randomblob(800) );
+  }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {13656 3176 1024}
+do_test 7.2.3 {
+  execsql { PRAGMA wal_checkpoint }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {13656 3176 1024}
+do_test 7.2.4 {
+  execsql { END } db2
+  execsql { PRAGMA wal_checkpoint }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {13656 3176 11264}
+
+# Connection db2 is holding a PART2_FULL1 lock. 
+#
+#   7.3.2: Test that the lock does not prevent checkpointing.
+#
+#   7.3.3: Test that the lock does prevent the writer from overwriting 
+#          test.db-wal.
+#
+#   7.3.4: Test that after the PART2_FULL1 is released the writer can
+#          switch wal files and overwrite test.db-wal
+#
+db close
+db2 close
+sqlite3 db test.db
+sqlite3 db2 test.db
+do_test 7.3.1 {
+  execsql {
+    PRAGMA wal_autocheckpoint = 0;
+    PRAGMA journal_size_limit = 10000;
+    INSERT INTO t1 VALUES(randomblob(10000));
+    INSERT INTO t1 VALUES(randomblob(500));
+  }
+  execsql {
+    BEGIN;
+      SELECT count(*) FROM t1;
+  } db2
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 3176 12288}
+do_test 7.3.2 {
+  execsql { PRAGMA wal_checkpoint }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 3176 22528}
+do_test 7.3.3 {
+  execsql { 
+    INSERT INTO t1 VALUES(randomblob(10000));
+    INSERT INTO t1 VALUES(randomblob(500));
+  }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 18896 22528}
+do_test 7.3.4 {
+  execsql END db2
+  execsql { INSERT INTO t1 VALUES(randomblob(5000)); }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 18896 22528}
+
+# Connection db2 is holding a PART2 lock. 
+#
+#   7.4.2: Test that the lock does not prevent writer switching to test.db-wal.
+#
+#   7.3.3: Test that the lock does prevent checkpointing of test.db-wal2.
+#
+#   7.3.4: Test that after the PART2 is released test.db-wal2 can be
+#          checkpointed.
+#
+db close
+db2 close
+breakpoint
+sqlite3 db test.db
+sqlite3 db2 test.db
+do_test 7.4.1 {
+  execsql {
+    PRAGMA wal_autocheckpoint = 0;
+    PRAGMA journal_size_limit = 10000;
+    INSERT INTO t1 VALUES(randomblob(10000));
+    INSERT INTO t1 VALUES(randomblob(10000));
+    PRAGMA wal_checkpoint;
+  }
+  execsql {
+    BEGIN;
+      SELECT count(*) FROM t1;
+  } db2
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 12608 50176}
+do_test 7.4.2 {
+  execsql { 
+    INSERT INTO t1 VALUES(randomblob(5000));
+  }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 12608 50176}
+do_test 7.4.3 {
+  execsql { PRAGMA wal_checkpoint }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 12608 50176}
+do_test 7.4.4 {
+  execsql END db2
+  execsql { PRAGMA wal_checkpoint }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 12608 60416}
+
+# Connection db2 is holding a PART1_FULL2 lock. 
+#
+#   7.5.2: Test that the lock does not prevent a checkpoint of test.db-wal2.
+#
+#   7.5.3: Test that the lock does prevent the writer from overwriting
+#          test.db-wal2.
+#
+#   7.5.4: Test that after the PART1_FULL2 lock is released, the writer
+#          can switch to test.db-wal2.
+#
+db close
+db2 close
+sqlite3 db test.db
+sqlite3 db2 test.db
+do_test 7.5.1 {
+  execsql {
+    PRAGMA wal_autocheckpoint = 0;
+    PRAGMA journal_size_limit = 10000;
+    INSERT INTO t1 VALUES(randomblob(10000));
+    INSERT INTO t1 VALUES(randomblob(10000));
+    PRAGMA wal_checkpoint;
+    INSERT INTO t1 VALUES(randomblob(5000));
+  }
+  execsql {
+    BEGIN;
+      SELECT count(*) FROM t1;
+  } db2
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 12608 76800}
+do_test 7.5.2 {
+  execsql { PRAGMA wal_checkpoint }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {12608 12608 87040}
+do_test 7.5.3.1 {
+  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {14704 12608 87040}
+do_test 7.5.3.2 {
+  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {22040 12608 87040}
+do_test 7.5.4 {
+  execsql END db2
+  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
+  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
+} {22040 12608 87040}
+
+
+finish_test
+
@@ -0,0 +1,93 @@
+# 2018 December 5
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+set testprefix wal2snapshot
+ifcapable !wal {finish_test ; return }
+ifcapable !snapshot {finish_test; return}
+
+foreach {tn mode} {1 wal 2 wal2} {
+  reset_db
+  do_execsql_test $tn.1 "PRAGMA journal_mode = $mode" $mode
+
+  do_execsql_test $tn.2 {
+    CREATE TABLE t1(a, b);
+    INSERT INTO t1 VALUES(1, 2);
+    INSERT INTO t1 VALUES(3, 4);
+    BEGIN;
+  }
+
+  # Check that sqlite3_snapshot_get() is an error for a wal2 db.
+  #
+  if {$tn==1} {
+    do_test 1.3 {
+      set S [sqlite3_snapshot_get db main]
+      sqlite3_snapshot_free $S
+    } {}
+  } else {
+    do_test 2.3 {
+      list [catch { sqlite3_snapshot_get db main } msg] $msg
+    } {1 SQLITE_ERROR}
+  }
+  
+  # Check that sqlite3_snapshot_recover() is an error for a wal2 db.
+  #
+  do_execsql_test $tn.4 COMMIT
+  if {$tn==1} {
+    do_test 1.5 {
+      sqlite3_snapshot_recover db main
+    } {}
+  } else {
+    do_test 2.5 {
+      list [catch { sqlite3_snapshot_recover db main } msg] $msg
+    } {1 SQLITE_ERROR}
+  }
+ 
+  # Check that sqlite3_snapshot_open() is an error for a wal2 db.
+  #
+  if {$tn==1} {
+    do_test 1.6 {
+      execsql BEGIN
+      set SNAPSHOT [sqlite3_snapshot_get_blob db main]
+      sqlite3_snapshot_open_blob db main $SNAPSHOT
+      execsql COMMIT
+    } {}
+  } else {
+    do_test 2.6.1 {
+      execsql BEGIN
+      set res [
+        list [catch { sqlite3_snapshot_open_blob db main $SNAPSHOT } msg] $msg
+      ]
+      execsql COMMIT
+      set res
+    } {1 SQLITE_ERROR}
+    do_test 2.6.2 {
+      execsql BEGIN
+      execsql {SELECT * FROM sqlite_master}
+      set res [
+        list [catch { sqlite3_snapshot_open_blob db main $SNAPSHOT } msg] $msg
+      ]
+      execsql COMMIT
+      set res
+    } {1 SQLITE_ERROR}
+  }
+}
+
+
+finish_test
+
+
@@ -85,7 +85,7 @@ proc lock_callback {method filename handle lock} {
    db2 eval { INSERT INTO x VALUES('x') }
  }
 }
-db timeout 10
+db timeout 1100
 do_catchsql_test 2.4 {
  BEGIN EXCLUSIVE;
 } {0 {}}
@@ -379,6 +379,8 @@ set options(THREADSAFE) {
 #endif
 }

+set options(WAL2) { "WAL2", }
+
 proc trim_name {in} {
  set ret $in
  if {[string range $in 0 6]=="SQLITE_"} {
@@ -1 +1 @@
 .43.0
 .43.1