Improvements to the DELETE code generator for the one-pass case. Avoid

some OP_Goto instructions.  Read content from the index cursor if the
index cursor is valid and was used to locate the row that is to be deleted.

FossilOrigin-Name: 58cc257aeb3ce75b8d3811b568cb8a677f6730a2

Makefile.msc

@@ -714,7 +714,7 @@ LIBRESOBJS =
 
 # All of the source code files.
 #
-SRC = \
+SRC1 = \
   $(TOP)\src\alter.c \
   $(TOP)\src\analyze.c \
   $(TOP)\src\attach.c \
@@ -764,7 +764,8 @@ SRC = \
   $(TOP)\src\os_setup.h \
   $(TOP)\src\os_unix.c \
   $(TOP)\src\os_win.c \
-  $(TOP)\src\os_win.h \
+  $(TOP)\src\os_win.h
+SRC2 = \
   $(TOP)\src\pager.c \
   $(TOP)\src\pager.h \
   $(TOP)\src\parse.y \
@@ -811,15 +812,14 @@ SRC = \
 
 # Source code for extensions
 #
-SRC = $(SRC) \
+SRC3 = \
   $(TOP)\ext\fts1\fts1.c \
   $(TOP)\ext\fts1\fts1.h \
   $(TOP)\ext\fts1\fts1_hash.c \
   $(TOP)\ext\fts1\fts1_hash.h \
   $(TOP)\ext\fts1\fts1_porter.c \
   $(TOP)\ext\fts1\fts1_tokenizer.h \
-  $(TOP)\ext\fts1\fts1_tokenizer1.c
-SRC = $(SRC) \
+  $(TOP)\ext\fts1\fts1_tokenizer1.c \
   $(TOP)\ext\fts2\fts2.c \
   $(TOP)\ext\fts2\fts2.h \
   $(TOP)\ext\fts2\fts2_hash.c \
@@ -829,7 +829,7 @@ SRC = $(SRC) \
   $(TOP)\ext\fts2\fts2_tokenizer.h \
   $(TOP)\ext\fts2\fts2_tokenizer.c \
   $(TOP)\ext\fts2\fts2_tokenizer1.c
-SRC = $(SRC) \
+SRC4 = \
   $(TOP)\ext\fts3\fts3.c \
   $(TOP)\ext\fts3\fts3.h \
   $(TOP)\ext\fts3\fts3Int.h \
@@ -846,18 +846,16 @@ SRC = $(SRC) \
   $(TOP)\ext\fts3\fts3_tokenize_vtab.c \
   $(TOP)\ext\fts3\fts3_unicode.c \
   $(TOP)\ext\fts3\fts3_unicode2.c \
-  $(TOP)\ext\fts3\fts3_write.c
-SRC = $(SRC) \
+  $(TOP)\ext\fts3\fts3_write.c \
   $(TOP)\ext\icu\sqliteicu.h \
-  $(TOP)\ext\icu\icu.c
-SRC = $(SRC) \
+  $(TOP)\ext\icu\icu.c \
   $(TOP)\ext\rtree\rtree.h \
   $(TOP)\ext\rtree\rtree.c
 
 
 # Generated source code files
 #
-SRC = $(SRC) \
+SRC5 = \
   keywordhash.h \
   opcodes.c \
   opcodes.h \
@@ -865,6 +863,10 @@ SRC = $(SRC) \
   parse.h \
   sqlite3.h
 
+# All source code files.
+#
+SRC = $(SRC1) $(SRC2) $(SRC3) $(SRC4) $(SRC5)
+
 # Source code to the test files.
 #
 TESTSRC = \
@@ -1052,7 +1054,11 @@ mptester.exe:	$(TOP)\mptest\mptest.c libsqlite3.lib $(LIBRESOBJS) sqlite3.h
 .target_source:	$(SRC) $(TOP)\tool\vdbe-compress.tcl
 	-rmdir /S/Q tsrc
 	-mkdir tsrc
-	for %i in ($(SRC)) do copy /Y %i tsrc
+	for %i in ($(SRC1)) do copy /Y %i tsrc
+	for %i in ($(SRC2)) do copy /Y %i tsrc
+	for %i in ($(SRC3)) do copy /Y %i tsrc
+	for %i in ($(SRC4)) do copy /Y %i tsrc
+	for %i in ($(SRC5)) do copy /Y %i tsrc
 	del /Q tsrc\sqlite.h.in tsrc\parse.y
 	$(TCLSH_CMD) $(TOP)\tool\vdbe-compress.tcl $(OPTS) < tsrc\vdbe.c > vdbe.new
 	move vdbe.new tsrc\vdbe.c

manifest

@@ -1,9 +1,9 @@
-C Fix\sharmless\scompiler\swarnings.
-D 2015-01-27T21:24:33.191
+C Improvements\sto\sthe\sDELETE\scode\sgenerator\sfor\sthe\sone-pass\scase.\s\sAvoid\nsome\sOP_Goto\sinstructions.\s\sRead\scontent\sfrom\sthe\sindex\scursor\sif\sthe\nindex\scursor\sis\svalid\sand\swas\sused\sto\slocate\sthe\srow\sthat\sis\sto\sbe\sdeleted.
+D 2015-01-29T15:53:19.350
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 5407a688f4d77a05c18a8142be8ae5a2829dd610
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
-F Makefile.msc 2b1cb8881bdefcb0a8ed41c34c81cfa630374222
+F Makefile.msc 1edfd7dd45d98a04f9a2fa81a01c49faeb628578
 F Makefile.vxworks e1b65dea203f054e71653415bd8f96dcaed47858
 F README.md d58e3bebc0a4145e0f2a87994015fdb575a8e866
 F VERSION d846487aff892625eb8e75960234e7285f0462fe
@@ -181,7 +181,7 @@ F src/callback.c 7b44ce59674338ad48b0e84e7b72f935ea4f68b0
 F src/complete.c 198a0066ba60ab06fc00fba1998d870a4d575463
 F src/ctime.c 98f89724adc891a1a4c655bee04e33e716e05887
 F src/date.c e4d50b3283696836ec1036b695ead9a19e37a5ac
-F src/delete.c bd1a91ddd247ce13004075251e0b7fe2bf9925ef
+F src/delete.c 66c10f83d3b0f37282f5b91f8a9192f4ce4a82c2
 F src/expr.c abe930897ccafae3819fd2855cbc1b00c262fd12
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c e0444b61bed271a76840cbe6182df93a9baa3f12
@@ -190,12 +190,12 @@ F src/global.c 12561d70a1b25f67b21154622bb1723426724f75
 F src/hash.c 4263fbc955f26c2e8cdc0cf214bc42435aa4e4f5
 F src/hash.h c8f3c31722cf3277d03713909761e152a5b81094
 F src/hwtime.h d32741c8f4df852c7d959236615444e2b1063b08
-F src/insert.c 5b9243a33726008cc4132897d2be371db12a13be
+F src/insert.c 57b087ad5c7580bd62b807dcdbd70c54b2bb4228
 F src/journal.c b4124532212b6952f42eb2c12fa3c25701d8ba8d
 F src/legacy.c ba1863ea58c4c840335a84ec276fc2b25e22bc4e
 F src/lempar.c 7274c97d24bb46631e504332ccd3bd1b37841770
 F src/loadext.c 86bd4e2fccd520b748cba52492ab60c4a770f660
-F src/main.c 05bf368c934cc73d02906030846eb4d1818c10f7
+F src/main.c 6a6688cf02372c744f8a67e7b396d53f378e49a2
 F src/malloc.c 740db54387204c9a2eb67c6d98e68b08e9ef4eab
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c abe6ee469b6c5a35c7f22bfeb9c9bac664a1c987
@@ -230,11 +230,11 @@ F src/random.c ba2679f80ec82c4190062d756f22d0c358180696
 F src/resolve.c f6c46d3434439ab2084618d603e6d6dbeb0d6ada
 F src/rowset.c eccf6af6d620aaa4579bd3b72c1b6395d9e9fa1e
 F src/select.c 1f2087523007c42900ffcbdeaef06a23ad9329fc
-F src/shell.c efd35900484377d2159189968c3445afefee3e41
-F src/sqlite.h.in 9dfc99d6533d36d6a549c4f3f01cacc8be956ada
+F src/shell.c ff4dafe42c9d282b06cbcaf0c285c553d7d5daa1
+F src/sqlite.h.in 7e7ce8ea342d59f109dcf3185374ebe1a6c0e4dd
 F src/sqlite3.rc 992c9f5fb8285ae285d6be28240a7e8d3a7f2bad
 F src/sqlite3ext.h 17d487c3c91b0b8c584a32fbeb393f6f795eea7d
-F src/sqliteInt.h eaf210295b551d4e40e622aec1b2261c0b28f844
+F src/sqliteInt.h d70bca4e33ee931a545172679a3013e15528c3bd
 F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
 F src/status.c 81712116e826b0089bb221b018929536b2b5406f
 F src/table.c e7a09215315a978057fb42c640f890160dbcc45e
@@ -292,7 +292,7 @@ F src/update.c 3c4ecc282accf12d39edb8d524cf089645e55a13
 F src/utf.c fc6b889ba0779b7722634cdeaa25f1930d93820c
 F src/util.c 98a7627ca48ad3265b6940915a1d08355eb3fc7e
 F src/vacuum.c 9b30ec729337dd012ed88d4c292922c8ef9cf00c
-F src/vdbe.c ddfc977981cd6324668aa6b114045eb1c677421a
+F src/vdbe.c 55f4db96c3d2bee17c66f244e4fc51fb0f09fed2
 F src/vdbe.h 6fc69d9c5e146302c56e163cb4b31d1ee64a18c3
 F src/vdbeInt.h 9bb69ff2447c34b6ccc58b34ec35b615f86ead78
 F src/vdbeapi.c 4bc511a46b9839392ae0e90844a71dc96d9dbd71
@@ -1237,7 +1237,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P adc9283dd9bc3a6463f8c4fe23dd58a3712c349d
-R 57729c2b510493b06603a65c6ea41133
-U mistachkin
-Z 7155fc25674fe331bcb8023f01301b6b
+P 0cdd59bf36aa4c2cad9a15bb7237643fb4222d55
+R 139902d9a4e02d98a72f3dedb9a073bc
+U drh
+Z ea315405c3cfce5f5aed8dbe7ead251e

manifest.uuid

@@ -1 +1 @@
-e7d2ec048c88237c124fbe598f8f7e950d43d90f
+58cc257aeb3ce75b8d3811b568cb8a677f6730a2

src/delete.c

@@ -247,7 +247,6 @@ void sqlite3DeleteFrom(
   int iRowSet = 0;       /* Register for rowset of rows to delete */
   int addrBypass = 0;    /* Address of jump over the delete logic */
   int addrLoop = 0;      /* Top of the delete loop */
-  int addrDelete = 0;    /* Jump directly to the delete logic */
   int addrEphOpen = 0;   /* Instruction to open the Ephemeral table */
  
 #ifndef SQLITE_OMIT_TRIGGER
@@ -437,7 +436,6 @@ void sqlite3DeleteFrom(
       if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0;
       if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0;
       if( addrEphOpen ) sqlite3VdbeChangeToNoop(v, addrEphOpen);
-      addrDelete = sqlite3VdbeAddOp0(v, OP_Goto); /* Jump to DELETE logic */
     }else if( pPk ){
       /* Construct a composite key for the row to be deleted and remember it */
       iKey = ++pParse->nMem;
@@ -451,13 +449,11 @@ void sqlite3DeleteFrom(
       sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey);
     }
   
-    /* End of the WHERE loop */
-    sqlite3WhereEnd(pWInfo);
+    /* End of the WHERE loop. */
     if( okOnePass ){
-      /* Bypass the delete logic below if the WHERE loop found zero rows */
       addrBypass = sqlite3VdbeMakeLabel(v);
-      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrBypass);
-      sqlite3VdbeJumpHere(v, addrDelete);
+    }else{
+      sqlite3WhereEnd(pWInfo);
     }
   
     /* Unless this is a view, open cursors for the table we are 
@@ -513,6 +509,7 @@ void sqlite3DeleteFrom(
   
     /* End of the loop over all rowids/primary-keys. */
     if( okOnePass ){
+      sqlite3WhereEnd(pWInfo);
       sqlite3VdbeResolveLabel(v, addrBypass);
     }else if( pPk ){
       sqlite3VdbeAddOp2(v, OP_Next, iEphCur, addrLoop+1); VdbeCoverage(v);
@@ -674,9 +671,11 @@ void sqlite3GenerateRowDelete(
   ** fire the INSTEAD OF triggers).  */ 
   if( pTab->pSelect==0 ){
     sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur, 0);
-    sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, (count?OPFLAG_NCHANGE:0));
-    if( count ){
-      sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_TRANSIENT);
+    if( !WRITE_RESTRICT(pParse->db, pTab->tnum) ){
+      sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, (count?OPFLAG_NCHANGE:0));
+      if( count ){
+        sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_TRANSIENT);
+      }
     }
   }
 
@@ -736,6 +735,7 @@ void sqlite3GenerateRowIndexDelete(
     assert( iIdxCur+i!=iDataCur || pPk==pIdx );
     if( aRegIdx!=0 && aRegIdx[i]==0 ) continue;
     if( pIdx==pPk ) continue;
+    if( WRITE_RESTRICT(pParse->db, pIdx->tnum) ) continue;
     VdbeModuleComment((v, "GenRowIdxDel for %s", pIdx->zName));
     r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 1,
                                  &iPartIdxLabel, pPrior, r1);

src/insert.c

@@ -1366,6 +1366,7 @@ void sqlite3GenerateConstraintChecks(
     int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */
 
     if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
+    if( WRITE_RESTRICT(db, pIdx->tnum) ) continue;
     if( bAffinityDone==0 ){
       sqlite3TableAffinity(v, pTab, regNewData+1);
       bAffinityDone = 1;
@@ -1545,6 +1546,7 @@ void sqlite3CompleteInsertion(
 ){
   Vdbe *v;            /* Prepared statements under construction */
   Index *pIdx;        /* An index being inserted or updated */
+  sqlite3 *db;
   u8 pik_flags;       /* flag values passed to the btree insert */
   int regData;        /* Content registers (after the rowid) */
   int regRec;         /* Register holding assembled record for the table */
@@ -1554,8 +1556,10 @@ void sqlite3CompleteInsertion(
   v = sqlite3GetVdbe(pParse);
   assert( v!=0 );
   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
+  db = pParse->db;
   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
     if( aRegIdx[i]==0 ) continue;
+    if( WRITE_RESTRICT(db, pIdx->tnum) ) continue;
     bAffinityDone = 1;
     if( pIdx->pPartIdxWhere ){
       sqlite3VdbeAddOp2(v, OP_IsNull, aRegIdx[i], sqlite3VdbeCurrentAddr(v)+2);
@@ -1571,6 +1575,7 @@ void sqlite3CompleteInsertion(
     if( pik_flags )  sqlite3VdbeChangeP5(v, pik_flags);
   }
   if( !HasRowid(pTab) ) return;
+  if( WRITE_RESTRICT(db, pTab->tnum) ) return;
   regData = regNewData + 1;
   regRec = sqlite3GetTempReg(pParse);
   sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);

src/main.c

@@ -725,6 +725,11 @@ int sqlite3_db_config(sqlite3 *db, int op, ...){
       rc = setupLookaside(db, pBuf, sz, cnt);
       break;
     }
+    case SQLITE_DBCONFIG_WRITABLE_BTREE: {
+      db->onlyWritableBtree = va_arg(ap,int);
+      rc = SQLITE_OK;
+      break;
+    }
     default: {
       static const struct {
         int op;      /* The opcode */

src/shell.c

@@ -2568,6 +2568,52 @@ static int do_meta_command(char *zLine, ShellState *p){
     }
   }else
 
+  if( c=='d' && n>1 && strncmp(azArg[0], "dbconfig", n)==0 ){
+    int nHit = 0, x;
+    open_db(p, 0);
+    if( nArg>=2 ){
+      n = (int)strlen(azArg[1]);
+      if( strncmp(azArg[1], "writable_btree",n)==0 ){
+        if( nArg!=3 ){
+          fprintf(stderr, "Usage: .dbconfig writable_btree N\n");
+          rc = 1;
+        }else{
+          sqlite3_db_config(p->db, SQLITE_DBCONFIG_WRITABLE_BTREE,
+                            integerValue(azArg[2]));
+        }
+        nHit = 1;
+      }else
+      if( strncmp(azArg[1], "enable_fkey",n)==0 ){
+        if( nArg!=3 ){
+          fprintf(stderr, "Usage: .dbconfig enable_fkey (1|0|-1)\n");
+          rc = 1;
+        }else{
+          sqlite3_db_config(p->db, SQLITE_DBCONFIG_ENABLE_FKEY,
+                            integerValue(azArg[2]), &x);
+          printf("result: %d\n", x);
+        }
+        nHit = 1;
+      }else
+      if( strncmp(azArg[1], "enable_trigger",n)==0 ){
+        if( nArg!=3 ){
+          fprintf(stderr, "Usage: .dbconfig enable_trigger (1|0|-1)\n");
+          rc = 1;
+        }else{
+          sqlite3_db_config(p->db, SQLITE_DBCONFIG_ENABLE_TRIGGER,
+                            integerValue(azArg[2]), &x);
+          printf("result: %d\n", x);
+        }
+        nHit = 1;
+      }
+    }
+    if( nHit==0 ){
+      fprintf(stderr, "Usage: .dbconfig COMMAND ARGS...\n");
+      fprintf(stderr, 
+        "COMMAND is one of: writable_btree enable_fkey enable_trigger\n");
+      rc = 1;
+    }    
+  }else
+
   if( c=='d' && strncmp(azArg[0], "dump", n)==0 ){
     open_db(p, 0);
     /* When playing back a "dump", the content might appear in an order

src/sqlite.h.in

@@ -1840,11 +1840,20 @@ struct sqlite3_mem_methods {
 ** following this call.  The second parameter may be a NULL pointer, in
 ** which case the trigger setting is not reported back. </dd>
 **
+** <dt>SQLITE_DBCONFIG_WRITABLE_BTREE</dt>
+** <dd> ^This option is used to disable INSERT and DELETE operations
+** against all attached b-trees, except for b-trees that have a 
+** particular root page. 
+** There must be one additional integer argument which is the root page
+** that is allowed to be written.  If the argument is zero, then
+** writing is allowed to all b-trees, as is normally the case.
+**
 ** </dl>
 */
 #define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
 #define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
 #define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
+#define SQLITE_DBCONFIG_WRITABLE_BTREE  1004  /* int */
 
 
 /*

src/sqliteInt.h

@@ -1077,6 +1077,7 @@ struct sqlite3 {
   u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */
   u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
   int nextPagesize;             /* Pagesize after VACUUM if >0 */
+  int onlyWritableBtree;        /* Do not write to any other b-tree */
   u32 magic;                    /* Magic number for detect library misuse */
   int nChange;                  /* Value returned by sqlite3_changes() */
   int nTotalChange;             /* Value returned by sqlite3_total_changes() */
@@ -1166,6 +1167,13 @@ struct sqlite3 {
 #endif
 };
 
+/*
+** This macro returns true if the only_writable_btree pragma is turned
+** on and is set to a btree root node other than N.
+*/
+#define WRITE_RESTRICT(db,N) ((db)->onlyWritableBtree>0 && \
+                              (db)->onlyWritableBtree!=(N))
+
 /*
 ** A macro to discover the encoding of a database.
 */

src/vdbe.c

@@ -4191,7 +4191,8 @@ case OP_Delete: {
   pC = p->apCsr[pOp->p1];
   assert( pC!=0 );
   assert( pC->pCursor!=0 );  /* Only valid for real tables, no pseudotables */
-  assert( pC->deferredMoveto==0 );
+  rc = sqlite3VdbeCursorMoveto(pC);
+  if( rc ) goto abort_due_to_error;
 
 #ifdef SQLITE_DEBUG
   /* The seek operation that positioned the cursor prior to OP_Delete will