Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
Comment: | Simplification of the skip-ahead-distinct logic. There is still an issue with handling COLLATE. |
---|---|
Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | skip-ahead-distinct |
Files: | files | file ages | folders |
SHA3-256: |
57c5173b6376a76013b0611ce9770100 |
User & Date: | drh 2017-04-13 19:48:29.675 |
Context
2017-04-13
| ||
21:29 | Fix the skip-ahead-distinct optimization so that it works with indexes that have repeated columns with different collating sequences. (check-in: ce1e2b8877 user: drh tags: skip-ahead-distinct) | |
19:48 | Simplification of the skip-ahead-distinct logic. There is still an issue with handling COLLATE. (check-in: 57c5173b63 user: drh tags: skip-ahead-distinct) | |
18:33 | New test cases and minor fixes for the optimization on this branch. (check-in: 70ac9ea1a6 user: dan tags: skip-ahead-distinct) | |
Changes
Changes to src/where.c.
︙ | ︙ | |||
3433 3434 3435 3436 3437 3438 3439 | } whereLoopClear(db, pNew); return rc; } /* | | | 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 | } whereLoopClear(db, pNew); return rc; } /* ** Examine a WherePath (with the addition of the extra WhereLoop of the 6th ** parameters) to see if it outputs rows in the requested ORDER BY ** (or GROUP BY) without requiring a separate sort operation. Return N: ** ** N>0: N terms of the ORDER BY clause are satisfied ** N==0: No terms of the ORDER BY clause are satisfied ** N<0: Unknown yet how many terms of ORDER BY might be satisfied. ** |
︙ | ︙ | |||
4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 | sqlite3ExprCacheClear(pParse); for(i=pWInfo->nLevel-1; i>=0; i--){ int addr; pLevel = &pWInfo->a[i]; pLoop = pLevel->pWLoop; if( pLevel->op!=OP_Noop ){ #ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT int n = -1; int j, k, op; int r1 = pParse->nMem+1; Index *pIdx; if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED && (pLoop->wsFlags & WHERE_INDEXED)!=0 && OptimizationEnabled(db, SQLITE_SkipAhead) | > | 4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 | sqlite3ExprCacheClear(pParse); for(i=pWInfo->nLevel-1; i>=0; i--){ int addr; pLevel = &pWInfo->a[i]; pLoop = pLevel->pWLoop; if( pLevel->op!=OP_Noop ){ #ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT int addrSeek = 0; int n = -1; int j, k, op; int r1 = pParse->nMem+1; Index *pIdx; if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED && (pLoop->wsFlags & WHERE_INDEXED)!=0 && OptimizationEnabled(db, SQLITE_SkipAhead) |
︙ | ︙ | |||
4893 4894 4895 4896 4897 4898 4899 | assert( 36==sqlite3LogEst(12) ); if( n>0 && pIdx->aiRowLogEst[n]>=36 ){ for(j=0; j<n; j++){ sqlite3VdbeAddOp3(v, OP_Column, pLevel->iIdxCur, j, r1+j); } pParse->nMem += n; op = pLevel->op==OP_Prev ? OP_SeekLT : OP_SeekGT; | | < < < < > < | | | | | | | | < > > > | 4894 4895 4896 4897 4898 4899 4900 4901 4902 4903 4904 4905 4906 4907 4908 4909 4910 4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 | assert( 36==sqlite3LogEst(12) ); if( n>0 && pIdx->aiRowLogEst[n]>=36 ){ for(j=0; j<n; j++){ sqlite3VdbeAddOp3(v, OP_Column, pLevel->iIdxCur, j, r1+j); } pParse->nMem += n; op = pLevel->op==OP_Prev ? OP_SeekLT : OP_SeekGT; addrSeek = sqlite3VdbeAddOp4Int(v, op, pLevel->iIdxCur, 0, r1, n); VdbeCoverageIf(v, op==OP_SeekLT); VdbeCoverageIf(v, op==OP_SeekGT); sqlite3VdbeAddOp2(v, OP_Goto, 1, pLevel->p2); } #endif /* SQLITE_DISABLE_SKIPAHEAD_DISTINCT */ /* The common case: Advance to the next row */ sqlite3VdbeResolveLabel(v, pLevel->addrCont); sqlite3VdbeAddOp3(v, pLevel->op, pLevel->p1, pLevel->p2, pLevel->p3); sqlite3VdbeChangeP5(v, pLevel->p5); VdbeCoverage(v); VdbeCoverageIf(v, pLevel->op==OP_Next); VdbeCoverageIf(v, pLevel->op==OP_Prev); VdbeCoverageIf(v, pLevel->op==OP_VNext); #ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT if( addrSeek ) sqlite3VdbeJumpHere(v, addrSeek); #endif }else{ sqlite3VdbeResolveLabel(v, pLevel->addrCont); } if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){ struct InLoop *pIn; int j; sqlite3VdbeResolveLabel(v, pLevel->addrNxt); |
︙ | ︙ |