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Overview
| Comment: | Fix another problem with the LIKE optimization. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | like-opt-fix |
| Files: | files | file ages | folders |
| SHA1: |
465bfc72d252f94778248253142faeba |
| User & Date: | drh 2015-03-07 20:32:49.790 |
Context
|
2015-03-09
| ||
| 12:11 | Always use LIKE optimization range constraints in pairs. (Closed-Leaf check-in: 0e02dc94fd user: drh tags: like-opt-fix) | |
|
2015-03-07
| ||
| 20:32 | Fix another problem with the LIKE optimization. (check-in: 465bfc72d2 user: drh tags: like-opt-fix) | |
| 13:56 | Fix the LIKE optimization so that it finds BLOB entries in addition to text entries. Ticket [05f43be8fdda9f]. (check-in: 74cb0b032f user: drh tags: trunk) | |
Changes
Changes to src/where.c.
| ︙ | ︙ | |||
3020 3021 3022 3023 3024 3025 3026 | ** The LIKE optimization trys to evaluate "x LIKE 'abc%'" as a range ** expression: "x>='ABC' AND x<'abd'". But this requires that the range ** scan loop run twice, once for strings and a second time for BLOBs. ** The OP_String opcodes on the second pass convert the upper and lower ** bound string contants to blobs. This routine makes the necessary changes ** to the OP_String opcodes for that to happen. */ | | | > > > > | > | 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 |
** The LIKE optimization trys to evaluate "x LIKE 'abc%'" as a range
** expression: "x>='ABC' AND x<'abd'". But this requires that the range
** scan loop run twice, once for strings and a second time for BLOBs.
** The OP_String opcodes on the second pass convert the upper and lower
** bound string contants to blobs. This routine makes the necessary changes
** to the OP_String opcodes for that to happen.
*/
static void whereLikeOptimizationStringFixup(
Vdbe *v, /* prepared statement under construction */
WhereLevel *pLevel, /* The loop that contains the LIKE operator */
WhereTerm *pTerm /* The upper or lower bound just coded */
){
if( pTerm->wtFlags & TERM_LIKEOPT ){
VdbeOp *pOp = sqlite3VdbeGetOp(v, -1);
if( pLevel->iLikeRepCntr && pOp->opcode==OP_String8 ){
pOp->p3 = pLevel->iLikeRepCntr;
pOp->p5 = 1;
}
}
}
/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
static Bitmask codeOneLoopStart(
WhereInfo *pWInfo, /* Complete information about the WHERE clause */
|
| ︙ | ︙ | |||
3361 3362 3363 3364 3365 3366 3367 |
if( pLoop->wsFlags & WHERE_BTM_LIMIT ){
pRangeStart = pLoop->aLTerm[j++];
nExtraReg = 1;
}
if( pLoop->wsFlags & WHERE_TOP_LIMIT ){
pRangeEnd = pLoop->aLTerm[j++];
nExtraReg = 1;
| < | | | 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 |
if( pLoop->wsFlags & WHERE_BTM_LIMIT ){
pRangeStart = pLoop->aLTerm[j++];
nExtraReg = 1;
}
if( pLoop->wsFlags & WHERE_TOP_LIMIT ){
pRangeEnd = pLoop->aLTerm[j++];
nExtraReg = 1;
if( (pRangeStart && (pRangeStart->wtFlags & TERM_LIKEOPT)!=0)
|| (pRangeEnd->wtFlags & TERM_LIKEOPT)!=0
){
pLevel->iLikeRepCntr = ++pParse->nMem;
testcase( bRev );
testcase( pIdx->aSortOrder[nEq]==SQLITE_SO_DESC );
sqlite3VdbeAddOp2(v, OP_Integer,
bRev ^ (pIdx->aSortOrder[nEq]==SQLITE_SO_DESC),
pLevel->iLikeRepCntr);
|
| ︙ | ︙ | |||
3416 3417 3418 3419 3420 3421 3422 |
start_constraints = pRangeStart || nEq>0;
/* Seek the index cursor to the start of the range. */
nConstraint = nEq;
if( pRangeStart ){
Expr *pRight = pRangeStart->pExpr->pRight;
sqlite3ExprCode(pParse, pRight, regBase+nEq);
| | | 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 |
start_constraints = pRangeStart || nEq>0;
/* Seek the index cursor to the start of the range. */
nConstraint = nEq;
if( pRangeStart ){
Expr *pRight = pRangeStart->pExpr->pRight;
sqlite3ExprCode(pParse, pRight, regBase+nEq);
whereLikeOptimizationStringFixup(v, pLevel, pRangeStart);
if( (pRangeStart->wtFlags & TERM_VNULL)==0
&& sqlite3ExprCanBeNull(pRight)
){
sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
VdbeCoverage(v);
}
if( zStartAff ){
|
| ︙ | ︙ | |||
3462 3463 3464 3465 3466 3467 3468 |
** range (if any).
*/
nConstraint = nEq;
if( pRangeEnd ){
Expr *pRight = pRangeEnd->pExpr->pRight;
sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);
sqlite3ExprCode(pParse, pRight, regBase+nEq);
| | | 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 |
** range (if any).
*/
nConstraint = nEq;
if( pRangeEnd ){
Expr *pRight = pRangeEnd->pExpr->pRight;
sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);
sqlite3ExprCode(pParse, pRight, regBase+nEq);
whereLikeOptimizationStringFixup(v, pLevel, pRangeEnd);
if( (pRangeEnd->wtFlags & TERM_VNULL)==0
&& sqlite3ExprCanBeNull(pRight)
){
sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
VdbeCoverage(v);
}
if( sqlite3CompareAffinity(pRight, cEndAff)!=SQLITE_AFF_NONE
|
| ︙ | ︙ |