Index: src/btree.c
==================================================================
--- src/btree.c
+++ src/btree.c
@@ -5748,11 +5748,11 @@
}
}
pPage = pCur->pPage;
idx = ++pCur->ix;
- if( !pPage->isInit ){
+ if( !pPage->isInit || sqlite3FaultSim(412) ){
/* The only known way for this to happen is for there to be a
** recursive SQL function that does a DELETE operation as part of a
** SELECT which deletes content out from under an active cursor
** in a corrupt database file where the table being DELETE-ed from
** has pages in common with the table being queried. See TH3
Index: src/vdbe.c
==================================================================
--- src/vdbe.c
+++ src/vdbe.c
@@ -4380,10 +4380,147 @@
assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
pOp++; /* Skip the OP_IdxLt or OP_IdxGT that follows */
}
break;
}
+
+
+/* Opcode: SeekScan P1 * * * *
+** Synopsis: Scan-ahead up to P1 rows
+**
+** This opcode is a prefix opcode to OP_SeekGE. In other words, this
+** opcode must be immediately followed by OP_SeekGE. Furthermore, the
+** OP_SeekGE must be followed by OP_IdxGT. These constraints are
+** checked by assert() statements.
+**
+** This opcode uses the P1 through P4 operands of the subsequent
+** OP_SeekGE. In the text that follows, the operands of the subsequent
+** OP_SeekGE opcode are denoted as SeekOP.P1 through SeekOP.P4. Only
+** the P1 operand of this opcode is used, and it is denoted as This.P1.
+**
+** This opcode helps to optimize IN operators on a multi-column index
+** where the IN operator is on the later terms of the index by avoiding
+** unnecessary seeks on the btree, substituting steps to the next row
+** of the b-tree instead. A correct answer is obtained if this opcode
+** is omitted or is a no-op.
+**
+** The SeekGE.P3 and SeekGE.P4 operands identify an unpacked key which
+** is the desired entry that we want the cursor SeekGE.P1 to be pointing
+** to. Call this SeekGE.P4/P5 row the "target".
+**
+** If the SeekGE.P1 cursor is not currently pointing to a valid row,
+** then this opcode is a no-op and control passes through into the OP_SeekGE.
+**
+** If the SeekGE.P1 cursor is pointing to a valid row, then that row
+** might be the target row, or it might be near and slightly before the
+** target row. This opcode attempts to position the cursor on the target
+** row by, perhaps stepping by invoking sqlite3BtreeStep() on the cursor
+** between 0 and This.P1 times.
+**
+** There are three possible outcomes from this opcode:
+**
+** - If after This.P1 steps, the cursor is still point to a place that
+** is earlier in the btree than the target row,
+** then fall through into the subsquence OP_SeekGE opcode.
+**
+**
- If the cursor is successfully moved to the target row by 0 or more
+** sqlite3BtreeNext() calls, then jump to the first instruction after the
+** OP_IdxGT opcode - or in other words, skip the next two opcodes.
+**
+**
- If the cursor ends up past the target row (indicating the the target
+** row does not exist in the btree) then jump to SeekOP.P2.
+**
+*/
+case OP_SeekScan: {
+ VdbeCursor *pC;
+ int res;
+ int n;
+ UnpackedRecord r;
+
+ assert( pOp[1].opcode==OP_SeekGE );
+ assert( pOp[2].opcode==OP_IdxGT );
+ assert( pOp[1].p1==pOp[2].p1 );
+ assert( pOp[1].p2==pOp[2].p2 );
+ assert( pOp[1].p3==pOp[2].p3 );
+ assert( pOp[1].p4.i==pOp[2].p4.i );
+ assert( pOp->p1>0 );
+ pC = p->apCsr[pOp[1].p1];
+ assert( pC!=0 );
+ assert( pC->eCurType==CURTYPE_BTREE );
+ assert( !pC->isTable );
+ if( !sqlite3BtreeCursorIsValidNN(pC->uc.pCursor) ){
+#ifdef SQLITE_DEBUG
+ if( db->flags&SQLITE_VdbeTrace ){
+ printf("... cursor not valid - fall through\n");
+ }
+#endif
+ break;
+ }
+ n = pOp->p1;
+ assert( n>=1 );
+ r.pKeyInfo = pC->pKeyInfo;
+ r.nField = (u16)pOp[1].p4.i;
+ r.default_rc = 0;
+ r.aMem = &aMem[pOp[1].p3];
+#ifdef SQLITE_DEBUG
+ {
+ int i;
+ for(i=0; i0 ){
+ seekscan_search_fail:
+#ifdef SQLITE_DEBUG
+ if( db->flags&SQLITE_VdbeTrace ){
+ printf("... %d steps and then skip\n", pOp->p1 - n);
+ }
+#endif
+ VdbeBranchTaken(1,3);
+ pOp++;
+ goto jump_to_p2;
+ }
+ if( res==0 ){
+#ifdef SQLITE_DEBUG
+ if( db->flags&SQLITE_VdbeTrace ){
+ printf("... %d steps and then success\n", pOp->p1 - n);
+ }
+#endif
+ VdbeBranchTaken(2,3);
+ pOp += 2;
+ break;
+ }
+ if( n<=0 ){
+#ifdef SQLITE_DEBUG
+ if( db->flags&SQLITE_VdbeTrace ){
+ printf("... fall through after %d steps\n", pOp->p1);
+ }
+#endif
+ VdbeBranchTaken(0,3);
+ break;
+ }
+ n--;
+ rc = sqlite3BtreeNext(pC->uc.pCursor, 0);
+ if( rc ){
+ if( rc==SQLITE_DONE ){
+ rc = SQLITE_OK;
+ goto seekscan_search_fail;
+ }else{
+ goto abort_due_to_error;
+ }
+ }
+ }
+
+ break;
+}
+
/* Opcode: SeekHit P1 P2 P3 * *
** Synopsis: set P2<=seekHit<=P3
**
** Increase or decrease the seekHit value for cursor P1, if necessary,
@@ -5912,22 +6049,45 @@
assert( memIsValid(&r.aMem[i]) );
REGISTER_TRACE(pOp->p3+i, &aMem[pOp->p3+i]);
}
}
#endif
- res = 0; /* Not needed. Only used to silence a warning. */
- rc = sqlite3VdbeIdxKeyCompare(db, pC, &r, &res);
+
+ /* Inlined version of sqlite3VdbeIdxKeyCompare() */
+ {
+ i64 nCellKey = 0;
+ BtCursor *pCur;
+ Mem m;
+
+ assert( pC->eCurType==CURTYPE_BTREE );
+ pCur = pC->uc.pCursor;
+ assert( sqlite3BtreeCursorIsValid(pCur) );
+ nCellKey = sqlite3BtreePayloadSize(pCur);
+ /* nCellKey will always be between 0 and 0xffffffff because of the way
+ ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
+ if( nCellKey<=0 || nCellKey>0x7fffffff ){
+ rc = SQLITE_CORRUPT_BKPT;
+ goto abort_due_to_error;
+ }
+ sqlite3VdbeMemInit(&m, db, 0);
+ rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
+ if( rc ) goto abort_due_to_error;
+ res = sqlite3VdbeRecordCompareWithSkip(m.n, m.z, &r, 0);
+ sqlite3VdbeMemRelease(&m);
+ }
+ /* End of inlined sqlite3VdbeIdxKeyCompare() */
+
assert( (OP_IdxLE&1)==(OP_IdxLT&1) && (OP_IdxGE&1)==(OP_IdxGT&1) );
if( (pOp->opcode&1)==(OP_IdxLT&1) ){
assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxLT );
res = -res;
}else{
assert( pOp->opcode==OP_IdxGE || pOp->opcode==OP_IdxGT );
res++;
}
VdbeBranchTaken(res>0,2);
- if( rc ) goto abort_due_to_error;
+ assert( rc==SQLITE_OK );
if( res>0 ) goto jump_to_p2;
break;
}
/* Opcode: Destroy P1 P2 P3 * *
Index: src/where.c
==================================================================
--- src/where.c
+++ src/where.c
@@ -2562,11 +2562,11 @@
safetyMargin = 10; /* TUNING: extra weight for indexed IN */
if( M + logK + safetyMargin < nIn + rLogSize ){
WHERETRACE(0x40,
("Scan preferred over IN operator on column %d of \"%s\" (%d<%d)\n",
saved_nEq, pProbe->zName, M+logK+10, nIn+rLogSize));
- continue;
+ pNew->wsFlags |= WHERE_IN_SEEKSCAN;
}else{
WHERETRACE(0x40,
("IN operator preferred on column %d of \"%s\" (%d>=%d)\n",
saved_nEq, pProbe->zName, M+logK+10, nIn+rLogSize));
}
@@ -5195,10 +5195,11 @@
sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb);
sqlite3VdbeSetP4KeyInfo(pParse, pIx);
if( (pLoop->wsFlags & WHERE_CONSTRAINT)!=0
&& (pLoop->wsFlags & (WHERE_COLUMN_RANGE|WHERE_SKIPSCAN))==0
&& (pLoop->wsFlags & WHERE_BIGNULL_SORT)==0
+ && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0
&& (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0
&& pWInfo->eDistinct!=WHERE_DISTINCT_ORDERED
){
sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ);
}
@@ -5357,11 +5358,13 @@
sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
if( pIn->eEndLoopOp!=OP_Noop ){
if( pIn->nPrefix ){
- assert( pLoop->wsFlags & WHERE_IN_EARLYOUT );
+ int bEarlyOut =
+ (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
+ && (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0;
if( pLevel->iLeftJoin ){
/* For LEFT JOIN queries, cursor pIn->iCur may not have been
** opened yet. This occurs for WHERE clauses such as
** "a = ? AND b IN (...)", where the index is on (a, b). If
** the RHS of the (a=?) is NULL, then the "b IN (...)" may
@@ -5368,16 +5371,14 @@
** never have been coded, but the body of the loop run to
** return the null-row. So, if the cursor is not open yet,
** jump over the OP_Next or OP_Prev instruction about to
** be coded. */
sqlite3VdbeAddOp2(v, OP_IfNotOpen, pIn->iCur,
- sqlite3VdbeCurrentAddr(v) + 2 +
- ((pLoop->wsFlags & WHERE_VIRTUALTABLE)==0)
- );
+ sqlite3VdbeCurrentAddr(v) + 2 + bEarlyOut);
VdbeCoverage(v);
}
- if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 ){
+ if( bEarlyOut ){
sqlite3VdbeAddOp4Int(v, OP_IfNoHope, pLevel->iIdxCur,
sqlite3VdbeCurrentAddr(v)+2,
pIn->iBase, pIn->nPrefix);
VdbeCoverage(v);
}
Index: src/whereInt.h
==================================================================
--- src/whereInt.h
+++ src/whereInt.h
@@ -617,7 +617,8 @@
#define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */
#define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/
#define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */
#define WHERE_IN_EARLYOUT 0x00040000 /* Perhaps quit IN loops early */
#define WHERE_BIGNULL_SORT 0x00080000 /* Column nEq of index is BIGNULL */
+#define WHERE_IN_SEEKSCAN 0x00100000 /* Seek-scan optimization for IN */
#endif /* !defined(SQLITE_WHEREINT_H) */
Index: src/wherecode.c
==================================================================
--- src/wherecode.c
+++ src/wherecode.c
@@ -568,11 +568,11 @@
pLoop->wsFlags |= WHERE_IN_ABLE;
if( pLevel->u.in.nIn==0 ){
pLevel->addrNxt = sqlite3VdbeMakeLabel(pParse);
}
- if( iEq>0 ){
+ if( iEq>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0 ){
pLoop->wsFlags |= WHERE_IN_EARLYOUT;
}
i = pLevel->u.in.nIn;
pLevel->u.in.nIn += nEq;
@@ -606,11 +606,11 @@
pIn->eEndLoopOp = OP_Noop;
}
pIn++;
}
}
- if( iEq>0 ){
+ if( iEq>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0 ){
sqlite3VdbeAddOp3(v, OP_SeekHit, pLevel->iIdxCur, 0, iEq);
}
}else{
pLevel->u.in.nIn = 0;
}
@@ -1802,10 +1802,24 @@
VdbeComment((v, "NULL-scan pass ctr"));
}
op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
assert( op!=0 );
+ if( (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 ){
+ assert( op==OP_SeekGE );
+ assert( regBignull==0 );
+ /* TUNING: The OP_SeekScan opcode seeks to reduce the number
+ ** of expensive seek operations by replacing a single seek with
+ ** 1 or more step operations. The question is, how many steps
+ ** should we try before giving up and going with a seek. The cost
+ ** of a seek is proportional to the logarithm of the of the number
+ ** of entries in the tree, so basing the number of steps to try
+ ** on the estimated number of rows in the btree seems like a good
+ ** guess. */
+ sqlite3VdbeAddOp1(v, OP_SeekScan, (pIdx->aiRowLogEst[0]+9)/10);
+ VdbeCoverage(v);
+ }
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
VdbeCoverage(v);
VdbeCoverageIf(v, op==OP_Rewind); testcase( op==OP_Rewind );
VdbeCoverageIf(v, op==OP_Last); testcase( op==OP_Last );
VdbeCoverageIf(v, op==OP_SeekGT); testcase( op==OP_SeekGT );
@@ -1904,11 +1918,11 @@
testcase( op==OP_IdxGE ); VdbeCoverageIf(v, op==OP_IdxGE );
testcase( op==OP_IdxLT ); VdbeCoverageIf(v, op==OP_IdxLT );
testcase( op==OP_IdxLE ); VdbeCoverageIf(v, op==OP_IdxLE );
}
- if( pLoop->wsFlags & WHERE_IN_EARLYOUT ){
+ if( (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0 ){
sqlite3VdbeAddOp3(v, OP_SeekHit, iIdxCur, nEq, nEq);
}
/* Seek the table cursor, if required */
omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0