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Enhancements to covering-index prediction. In particular, avoid the

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false-positive prediction described by
[forum:/forumpost/e60e4c295d22f8ce|forum post e60e4c295d22f8ce].
Add early detection of over-prediction of covering-indexes so that
sqlite3_prepare() will return an error rather than just generate bad
bytecode.

FossilOrigin-Name: f0b671183f44d0ae294956e7651a1653f47bd6219f9636872d15993f30f28dfb
This commit is contained in:
drh
2024-08-10 10:05:22 +00:00
parent 4098aa5d19 c5900bfd59
commit fe4ed96006
3 changed files with 26 additions and 47 deletions
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src/where.c
+18 -40
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@@ -4047,7 +4047,9 @@ static int whereLoopAddBtree(
" according to whereIsCoveringIndex()\n", pProbe->zName));
}
}
}else if( m==0 ){
}else if( m==0
&& (HasRowid(pTab) || pWInfo->pSelect!=0 || sqlite3FaultSim(700))
){
WHERETRACE(0x200,
("-> %s a covering index according to bitmasks\n",
pProbe->zName, m==0 ? "is" : "is not"));
@@ -7078,26 +7080,6 @@ whereBeginError:
}
#endif
#ifdef SQLITE_DEBUG
/*
** Return true if cursor iCur is opened by instruction k of the
** bytecode. Used inside of assert() only.
*/
static int cursorIsOpen(Vdbe *v, int iCur, int k){
while( k>=0 ){
VdbeOp *pOp = sqlite3VdbeGetOp(v,k--);
if( pOp->p1!=iCur ) continue;
if( pOp->opcode==OP_Close ) return 0;
if( pOp->opcode==OP_OpenRead ) return 1;
if( pOp->opcode==OP_OpenWrite ) return 1;
if( pOp->opcode==OP_OpenDup ) return 1;
if( pOp->opcode==OP_OpenAutoindex ) return 1;
if( pOp->opcode==OP_OpenEphemeral ) return 1;
}
return 0;
}
#endif /* SQLITE_DEBUG */
/*
** Generate the end of the WHERE loop. See comments on
** sqlite3WhereBegin() for additional information.
@@ -7376,18 +7358,20 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
assert( pIdx->pTable==pTab );
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
if( pOp->opcode==OP_Offset ){
/* Do not need to translate the column number */
x = 0;
}else
#endif
if( !HasRowid(pTab) ){
Index *pPk = sqlite3PrimaryKeyIndex(pTab);
x = pPk->aiColumn[x];
assert( x>=0 );
}else{
testcase( x!=sqlite3StorageColumnToTable(pTab,x) );
x = sqlite3StorageColumnToTable(pTab,x);
{
if( !HasRowid(pTab) ){
Index *pPk = sqlite3PrimaryKeyIndex(pTab);
x = pPk->aiColumn[x];
assert( x>=0 );
}else{
testcase( x!=sqlite3StorageColumnToTable(pTab,x) );
x = sqlite3StorageColumnToTable(pTab,x);
}
x = sqlite3TableColumnToIndex(pIdx, x);
}
x = sqlite3TableColumnToIndex(pIdx, x);
if( x>=0 ){
pOp->p2 = x;
pOp->p1 = pLevel->iIdxCur;
@@ -7397,16 +7381,10 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
** reference. Verify that this is harmless - that the
** table being referenced really is open.
*/
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
|| cursorIsOpen(v,pOp->p1,k)
|| pOp->opcode==OP_Offset
);
#else
assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
|| cursorIsOpen(v,pOp->p1,k)
);
#endif
if( pLoop->wsFlags & WHERE_IDX_ONLY ){
sqlite3ErrorMsg(pParse, "internal query planner error");
pParse->rc = SQLITE_INTERNAL;
}
}
}else if( pOp->opcode==OP_Rowid ){
pOp->p1 = pLevel->iIdxCur;