Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
| Comment: | Fixes to the skip-ahead distinct logic. More issues remain. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | skip-ahead-distinct |
| Files: | files | file ages | folders |
| SHA1: |
45a70b2bb8f7b465bab45d2eaad24d37 |
| User & Date: | drh 2016-04-15 15:54:17 |
Context
|
2016-04-15
| ||
| 16:17 | Skip-ahead does not always work. So we still have to check for redundancy. check-in: db5a2364 user: drh tags: skip-ahead-distinct | |
| 15:54 | Fixes to the skip-ahead distinct logic. More issues remain. check-in: 45a70b2b user: drh tags: skip-ahead-distinct | |
| 15:06 | Merge enhancements from trunk, especially the ".eqp full" enhancement to the command-line shell. check-in: 491f0dbd user: drh tags: skip-ahead-distinct | |
Changes
Changes to src/where.c.
4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 |
pLevel = &pWInfo->a[i];
pLoop = pLevel->pWLoop;
sqlite3VdbeResolveLabel(v, pLevel->addrCont);
if( pLevel->op!=OP_Noop ){
if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED
&& (pLoop->wsFlags & WHERE_INDEXED)!=0
){
int j, k, op;
int r1 = pParse->nMem+1;
int n = 0;
ExprList *pX = pWInfo->pDistinctSet;
for(j=0; j<pX->nExpr; j++){
Expr *pE = sqlite3ExprSkipCollate(pX->a[j].pExpr);
if( pE->op==TK_COLUMN && pE->iTable==pLevel->iTabCur ) n++;
}
for(j=0; j<n; j++){
sqlite3VdbeAddOp3(v, OP_Column, pLevel->iIdxCur, j, r1+j);
}
pParse->nMem += n;
if( n>0 ){
op = pLevel->op==OP_Prev ? OP_SeekLT : OP_SeekGT;
k = 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);
sqlite3VdbeJumpHere(v, k);
}
}else{
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);
}
|
> > > > | > | > > > > > > > > > | > > > > | | | | < > |
4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 |
pLevel = &pWInfo->a[i];
pLoop = pLevel->pWLoop;
sqlite3VdbeResolveLabel(v, pLevel->addrCont);
if( pLevel->op!=OP_Noop ){
if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED
&& (pLoop->wsFlags & WHERE_INDEXED)!=0
){
/* This is the Skip-ahead optimization. When doing a DISTINCT query
** that has WHERE_DISTINCT_ORDERED, use OP_SkipGT/OP_SkipLT to skip
** over all duplicate entries, rather than visiting all duplicates
** using OP_Next/OP_Prev. */
int j, k, op;
int r1 = pParse->nMem+1;
int n = -1;
ExprList *pX = pWInfo->pDistinctSet;
Index *pIdx = pLoop->u.btree.pIndex;
for(j=0; j<pX->nExpr; j++){
Expr *pE = sqlite3ExprSkipCollate(pX->a[j].pExpr);
if( pE->op==TK_COLUMN ){
if( pE->iTable!=pLevel->iTabCur ) continue;
k = 1+sqlite3ColumnOfIndex(pIdx, pE->iColumn);
if( k>n ) n = k;
}else if( pIdx->aColExpr ){
for(k=n+1; k<pIdx->nKeyCol; k++){
Expr *pI = pIdx->aColExpr->a[k].pExpr;
if( pI && sqlite3ExprCompare(pE,pI,0)<2 ){
n = k+1;
break;
}
}
}
}
if( n>0 ){
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;
k = 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);
sqlite3VdbeJumpHere(v, k);
}
}else{
/* The common case: Advance to the next row */
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);
}
|