Performance optimization to the OP_Next and OP_Prev opcodes.

FossilOrigin-Name: ecaac28a2e78aca148fc614fe54bf2706aed8be2

manifest

@@ -1,5 +1,5 @@
-C Refactor\sthe\sOP_Column\sopcode\sto\smake\sit\sclearer\sand\seasier\sto\smaintain.\nOverall,\sperformance\stests\sshow\sabout\sa\s1%\sspeed\sincrease\swith\sthis\schange.
-D 2013-11-21T01:33:45.684
+C Performance\soptimization\sto\sthe\sOP_Next\sand\sOP_Prev\sopcodes.
+D 2013-11-21T03:12:25.082
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 8a07bebafbfda0eb67728f4bd15a36201662d1a1
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -280,11 +280,11 @@ F src/update.c c05a0ee658f1a149e0960dfd110f3b8bd846bcb0
 F src/utf.c 6fc6c88d50448c469c5c196acf21617a24f90269
 F src/util.c 2fa6c821d28bbdbeec1b2a7b091a281c9ef8f918
 F src/vacuum.c 3728d74919d4fb1356f9e9a13e27773db60b7179
-F src/vdbe.c c375ba0385f747e58d98686f5f4f0439c6297b35
+F src/vdbe.c 1aabde68130182a3cceb70d1c59122b93244b97e
 F src/vdbe.h c06f0813f853566457ce9cfb1a4a4bc39a5da644
 F src/vdbeInt.h 0ac03c790b8ea4568b747550ba9bbf92a8e8feb2
 F src/vdbeapi.c 93a22a9ba2abe292d5c2cf304d7eb2e894dde0ed
-F src/vdbeaux.c bbf06ccbb159611d55e32783c6e9fdec75b120d0
+F src/vdbeaux.c 648f72365268979e89cd2ba8e5f2b4ecb1843fb0
 F src/vdbeblob.c 8cd05a5630e6d5563ad017bf82edaf812b28acde
 F src/vdbemem.c cc529bbf4f13e4e181bdb446bf6e6962ab030b4b
 F src/vdbesort.c 9d83601f9d6243fe70dd0169a2820c5ddfd48147
@@ -293,7 +293,7 @@ F src/vtab.c 21b932841e51ebd7d075e2d0ad1415dce8d2d5fd
 F src/wal.c 7dc3966ef98b74422267e7e6e46e07ff6c6eb1b4
 F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
 F src/walker.c e9e593d5bb798c3e67fc3893dfe7055c9e7d8d74
-F src/where.c aa72ba871fa835a513cae1c7432dc1d785eb23e4
+F src/where.c e558bfa67009ab7de08a7a1960ae0dd443241cdd
 F src/whereInt.h 96a75c61f1d2b9d4a8e4bb17d89deb0cf7cba358
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
@@ -1140,8 +1140,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P 5562cd343d8f69242e06a51a7f1aef7ee7d78eec 933939932c44bccb0958f203a5bd24e683c1cf38
-R 842b8e02c5c12ba51889f25ba6cef74b
-T +closed 933939932c44bccb0958f203a5bd24e683c1cf38
+P 972881c6d394c199961f01dcbeb4a6e8b5c919a1
+R d4a5420dc1635b387e6b0a099e73a8c3
 U drh
-Z 16455d71573d7ca0de3f10177a1e6082
+Z 0f90f7ea40ab09ca14f9f529358ed102

manifest.uuid

@@ -1 +1 @@
-972881c6d394c199961f01dcbeb4a6e8b5c919a1
+ecaac28a2e78aca148fc614fe54bf2706aed8be2

src/vdbe.c

@@ -4467,7 +4467,8 @@ case OP_Rewind: {        /* jump */
 ** to the following instruction.  But if the cursor advance was successful,
 ** jump immediately to P2.
 **
-** The P1 cursor must be for a real table, not a pseudo-table.
+** The P1 cursor must be for a real table, not a pseudo-table.  P1 must have
+** been opened prior to this opcode or the program will segfault.
 **
 ** P4 is always of type P4_ADVANCE. The function pointer points to
 ** sqlite3BtreeNext().
@@ -4475,7 +4476,12 @@ case OP_Rewind: {        /* jump */
 ** If P5 is positive and the jump is taken, then event counter
 ** number P5-1 in the prepared statement is incremented.
 **
-** See also: Prev
+** See also: Prev, NextIfOpen
+*/
+/* Opcode: NextIfOpen P1 P2 * * P5
+**
+** This opcode works just like OP_Next except that if cursor P1 is not
+** open it behaves a no-op.
 */
 /* Opcode: Prev P1 P2 * * P5
 **
@@ -4484,7 +4490,8 @@ case OP_Rewind: {        /* jump */
 ** to the following instruction.  But if the cursor backup was successful,
 ** jump immediately to P2.
 **
-** The P1 cursor must be for a real table, not a pseudo-table.
+** The P1 cursor must be for a real table, not a pseudo-table.  If P1 is
+** not open then the behavior is undefined.
 **
 ** P4 is always of type P4_ADVANCE. The function pointer points to
 ** sqlite3BtreePrevious().
@@ -4492,38 +4499,47 @@ case OP_Rewind: {        /* jump */
 ** If P5 is positive and the jump is taken, then event counter
 ** number P5-1 in the prepared statement is incremented.
 */
-case OP_SorterNext:    /* jump */
-case OP_Prev:          /* jump */
-case OP_Next: {        /* jump */
+/* Opcode: PrevIfOpen P1 P2 * * P5
+**
+** This opcode works just like OP_Prev except that if cursor P1 is not
+** open it behaves a no-op.
+*/
+case OP_SorterNext: {  /* jump */
   VdbeCursor *pC;
   int res;
 
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  rc = sqlite3VdbeSorterNext(db, pC, &res);
+  goto next_tail;
+case OP_PrevIfOpen:    /* jump */
+case OP_NextIfOpen:    /* jump */
+  if( p->apCsr[pOp->p1]==0 ) break;
+  /* Fall through */
+case OP_Prev:          /* jump */
+case OP_Next:          /* jump */
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   assert( pOp->p5<ArraySize(p->aCounter) );
   pC = p->apCsr[pOp->p1];
-  if( pC==0 ){
-    break;  /* See ticket #2273 */
-  }
-  assert( isSorter(pC)==(pOp->opcode==OP_SorterNext) );
-  if( isSorter(pC) ){
-    assert( pOp->opcode==OP_SorterNext );
-    rc = sqlite3VdbeSorterNext(db, pC, &res);
-  }else{
-    /* res = 1; // Always initialized by the xAdvance() call */
-    assert( pC->deferredMoveto==0 );
-    assert( pC->pCursor );
-    assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
-    assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
-    rc = pOp->p4.xAdvance(pC->pCursor, &res);
-  }
-  pC->nullRow = (u8)res;
+  assert( pC!=0 );
+  assert( pC->deferredMoveto==0 );
+  assert( pC->pCursor );
+  assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
+  assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
+  assert( pOp->opcode!=OP_NextIfOpen || pOp->p4.xAdvance==sqlite3BtreeNext );
+  assert( pOp->opcode!=OP_PrevIfOpen || pOp->p4.xAdvance==sqlite3BtreePrevious);
+  rc = pOp->p4.xAdvance(pC->pCursor, &res);
+next_tail:
   pC->cacheStatus = CACHE_STALE;
   if( res==0 ){
+    pC->nullRow = 0;
     pc = pOp->p2 - 1;
     p->aCounter[pOp->p5]++;
 #ifdef SQLITE_TEST
     sqlite3_search_count++;
 #endif
+  }else{
+    pC->nullRow = 1;
   }
   pC->rowidIsValid = 0;
   goto check_for_interrupt;

src/vdbeaux.c

@@ -453,12 +453,14 @@ static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
       }
 #endif
       case OP_Next:
+      case OP_NextIfOpen:
       case OP_SorterNext: {
         pOp->p4.xAdvance = sqlite3BtreeNext;
         pOp->p4type = P4_ADVANCE;
         break;
       }
-      case OP_Prev: {
+      case OP_Prev:
+      case OP_PrevIfOpen: {
         pOp->p4.xAdvance = sqlite3BtreePrevious;
         pOp->p4type = P4_ADVANCE;
         break;

src/where.c

@@ -2406,7 +2406,7 @@ static int codeEqualityTerm(
       }else{
         pIn->addrInTop = sqlite3VdbeAddOp3(v, OP_Column, iTab, 0, iReg);
       }
-      pIn->eEndLoopOp = bRev ? OP_Prev : OP_Next;
+      pIn->eEndLoopOp = bRev ? OP_PrevIfOpen : OP_NextIfOpen;
       sqlite3VdbeAddOp1(v, OP_IsNull, iReg);
     }else{
       pLevel->u.in.nIn = 0;