Overview
Comment: | Progress toward getting DISTINCT to use a seek to advance to the next distinct row, when driven by an appropriate index. |
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Downloads: | Tarball | ZIP archive | SQL archive |
Timelines: | family | ancestors | descendants | both | skip-ahead-distinct |
Files: | files | file ages | folders |
SHA1: | 9e14aa14cff7ebf7a5e93ce7377838da129d585f |
User & Date: | drh 2016-04-15 01:55:49 |
Context
2016-04-15
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13:24 | Fixed crash bugs. Still sometimes gets the wrong answers. check-in: 2afcb2c7 user: drh tags: skip-ahead-distinct | |
01:55 | Progress toward getting DISTINCT to use a seek to advance to the next distinct row, when driven by an appropriate index. check-in: 9e14aa14 user: drh tags: skip-ahead-distinct | |
2016-04-14
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19:29 | Work toward improving analysis and code generation for DISTINCT and aggregate queries. Leaf check-in: 129083bd user: drh tags: better-distinct-agg | |
Changes
Changes to src/select.c.
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/* If the DISTINCT keyword was present on the SELECT statement
** and this row has been seen before, then do not make this row
** part of the result.
*/
if( hasDistinct ){
switch( pDistinct->eTnctType ){
case WHERE_DISTINCT_ORDERED: {
VdbeOp *pOp; /* No longer required OpenEphemeral instr. */
int iJump; /* Jump destination */
int regPrev; /* Previous row content */
/* Allocate space for the previous row */
regPrev = pParse->nMem+1;
pParse->nMem += nResultCol;
................................................................................
}
sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
}
assert( sqlite3VdbeCurrentAddr(v)==iJump || pParse->db->mallocFailed );
sqlite3VdbeAddOp3(v, OP_Copy, regResult, regPrev, nResultCol-1);
break;
}
case WHERE_DISTINCT_UNIQUE: {
sqlite3VdbeChangeToNoop(v, pDistinct->addrTnct);
break;
}
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/* If the DISTINCT keyword was present on the SELECT statement ** and this row has been seen before, then do not make this row ** part of the result. */ if( hasDistinct ){ switch( pDistinct->eTnctType ){ case WHERE_DISTINCT_ORDERED: { #if 0 VdbeOp *pOp; /* No longer required OpenEphemeral instr. */ int iJump; /* Jump destination */ int regPrev; /* Previous row content */ /* Allocate space for the previous row */ regPrev = pParse->nMem+1; pParse->nMem += nResultCol; ................................................................................ } sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ); sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); } assert( sqlite3VdbeCurrentAddr(v)==iJump || pParse->db->mallocFailed ); sqlite3VdbeAddOp3(v, OP_Copy, regResult, regPrev, nResultCol-1); break; #endif } case WHERE_DISTINCT_UNIQUE: { sqlite3VdbeChangeToNoop(v, pDistinct->addrTnct); break; } |
Changes to src/shell.c.
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if( str_in_array(zOp, azNext) ){
for(i=p2op; i<iOp; i++) p->aiIndent[i] += 2;
}
if( str_in_array(zOp, azGoto) && p2op<p->nIndent
&& (abYield[p2op] || sqlite3_column_int(pSql, 2))
){
for(i=p2op+1; i<iOp; i++) p->aiIndent[i] += 2;
}
}
p->iIndent = 0;
sqlite3_free(abYield);
sqlite3_reset(pSql);
}
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if( str_in_array(zOp, azNext) ){ for(i=p2op; i<iOp; i++) p->aiIndent[i] += 2; } if( str_in_array(zOp, azGoto) && p2op<p->nIndent && (abYield[p2op] || sqlite3_column_int(pSql, 2)) ){ for(i=p2op; i<iOp; i++) p->aiIndent[i] += 2; } } p->iIndent = 0; sqlite3_free(abYield); sqlite3_reset(pSql); } |
Changes to src/where.c.
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/* Load the lowest cost path into pWInfo */ for(iLoop=0; iLoop<nLoop; iLoop++){ WhereLevel *pLevel = pWInfo->a + iLoop; pLevel->pWLoop = pWLoop = pFrom->aLoop[iLoop]; pLevel->iFrom = pWLoop->iTab; pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor; } if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0 && (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0 && pWInfo->eDistinct==WHERE_DISTINCT_NOOP && nRowEst ){ Bitmask notUsed; int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pDistinctSet, pFrom, ................................................................................ assert( iIndexCur>=0 ); if( op ){ sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb); sqlite3VdbeSetP4KeyInfo(pParse, pIx); if( (pLoop->wsFlags & WHERE_CONSTRAINT)!=0 && (pLoop->wsFlags & (WHERE_COLUMN_RANGE|WHERE_SKIPSCAN))==0 && (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0 ){ sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ); /* Hint to COMDB2 */ } VdbeComment((v, "%s", pIx->zName)); #ifdef SQLITE_ENABLE_COLUMN_USED_MASK { u64 colUsed = 0; ................................................................................ WhereLoop *pLoop; SrcList *pTabList = pWInfo->pTabList; sqlite3 *db = pParse->db; /* Generate loop termination code. */ VdbeModuleComment((v, "End WHERE-core")); sqlite3ExprCacheClear(pParse); for(i=pWInfo->nLevel-1; i>=0; i--){ int addr; pLevel = &pWInfo->a[i]; pLoop = pLevel->pWLoop; sqlite3VdbeResolveLabel(v, pLevel->addrCont); if( pLevel->op!=OP_Noop ){ 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); } if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){ struct InLoop *pIn; int j; 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); |
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/* Load the lowest cost path into pWInfo */ for(iLoop=0; iLoop<nLoop; iLoop++){ WhereLevel *pLevel = pWInfo->a + iLoop; pLevel->pWLoop = pWLoop = pFrom->aLoop[iLoop]; pLevel->iFrom = pWLoop->iTab; pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor; } assert( pWInfo->pDistinctSet || (pWInfo->wctrlFlags&WHERE_WANT_DISTINCT)==0 ); if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0 && (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0 && pWInfo->eDistinct==WHERE_DISTINCT_NOOP && nRowEst ){ Bitmask notUsed; int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pDistinctSet, pFrom, ................................................................................ assert( iIndexCur>=0 ); if( op ){ sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb); sqlite3VdbeSetP4KeyInfo(pParse, pIx); if( (pLoop->wsFlags & WHERE_CONSTRAINT)!=0 && (pLoop->wsFlags & (WHERE_COLUMN_RANGE|WHERE_SKIPSCAN))==0 && (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0 && pWInfo->eDistinct!=WHERE_DISTINCT_ORDERED ){ sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ); /* Hint to COMDB2 */ } VdbeComment((v, "%s", pIx->zName)); #ifdef SQLITE_ENABLE_COLUMN_USED_MASK { u64 colUsed = 0; ................................................................................ WhereLoop *pLoop; SrcList *pTabList = pWInfo->pTabList; sqlite3 *db = pParse->db; /* Generate loop termination code. */ VdbeModuleComment((v, "End WHERE-core")); assert( pWInfo->eDistinct!=WHERE_DISTINCT_ORDERED || pWInfo->pDistinctSet!=0); sqlite3ExprCacheClear(pParse); for(i=pWInfo->nLevel-1; i>=0; i--){ int addr; pLevel = &pWInfo->a[i]; pLoop = pLevel->pWLoop; sqlite3VdbeResolveLabel(v, pLevel->addrCont); if( pLevel->op!=OP_Noop ){ if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED ){ 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; 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); } } if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){ struct InLoop *pIn; int j; 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); |