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Overview
| Comment: | Only run the constant propagation optimization on joins since that is the only scenario where it is useful. This saves prepare time for the common case of a simple query. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | propagate-const-opt |
| Files: | files | file ages | folders |
| SHA3-256: |
598d608359005b13fa1151c6c69f2fd1 |
| User & Date: | drh 2018-07-27 17:51:20.481 |
Context
|
2018-07-27
| ||
| 18:12 | Faster implementation of sqlite3IsBinary(). (check-in: be05d0db09 user: drh tags: propagate-const-opt) | |
| 17:51 | Only run the constant propagation optimization on joins since that is the only scenario where it is useful. This saves prepare time for the common case of a simple query. (check-in: 598d608359 user: drh tags: propagate-const-opt) | |
| 16:57 | Constant propagation is now restricted to just the WHERE clause. The mechanism is changed to take affinity and collation into account. This seems to give correct answers. But the search for constant propagation costs 4 million cycles in the speed test. (check-in: 82c67efb72 user: drh tags: propagate-const-opt) | |
Changes
Changes to src/expr.c.
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return pColl;
}
/*
** Return true if CollSeq is the default built-in BINARY.
*/
int sqlite3IsBinary(const CollSeq *p){
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return pColl;
}
/*
** Return true if CollSeq is the default built-in BINARY.
*/
int sqlite3IsBinary(const CollSeq *p){
return p==0 || sqlite3StrICmp(p->zName,sqlite3StrBINARY)==0;
}
/*
** Generate code for a comparison operator.
*/
static int codeCompare(
Parse *pParse, /* The parsing (and code generating) context */
|
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Changes to src/select.c.
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}
#endif
if( p->pNext==0 ) ExplainQueryPlanPop(pParse);
return rc;
}
#endif
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}
#endif
if( p->pNext==0 ) ExplainQueryPlanPop(pParse);
return rc;
}
#endif
/* Do the WHERE-clause constant propagation optimization if this is
** a join. No need to speed time on this operation for non-join queries
** as the equivalent optimization will be handled by query planner in
** sqlite3WhereBegin().
*/
if( pTabList->nSrc>1
&& OptimizationEnabled(db, SQLITE_PropagateConst)
&& propagateConstants(pParse, p)
){
#if SELECTTRACE_ENABLED
if( sqlite3SelectTrace & 0x100 ){
SELECTTRACE(0x100,pParse,p,("After constant propagation:\n"));
sqlite3TreeViewSelect(0, p, 0);
}
#endif
}else{
SELECTTRACE(0x100,pParse,p,("Constant propagation not helpful\n"));
}
/* For each term in the FROM clause, do two things:
** (1) Authorized unreferenced tables
** (2) Generate code for all sub-queries
*/
for(i=0; i<pTabList->nSrc; i++){
|
| ︙ | ︙ |
Changes to src/where.c.
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3201 3202 3203 3204 3205 3206 3207 |
if( iCons>=0 && iCons<pIdxInfo->nConstraint ){
CollSeq *pC = 0;
int iTerm = pIdxInfo->aConstraint[iCons].iTermOffset;
Expr *pX = pHidden->pWC->a[iTerm].pExpr;
if( pX->pLeft ){
pC = sqlite3BinaryCompareCollSeq(pHidden->pParse, pX->pLeft, pX->pRight);
}
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if( iCons>=0 && iCons<pIdxInfo->nConstraint ){
CollSeq *pC = 0;
int iTerm = pIdxInfo->aConstraint[iCons].iTermOffset;
Expr *pX = pHidden->pWC->a[iTerm].pExpr;
if( pX->pLeft ){
pC = sqlite3BinaryCompareCollSeq(pHidden->pParse, pX->pLeft, pX->pRight);
}
zRet = (pC ? pC->zName : sqlite3StrBINARY);
}
return zRet;
}
/*
** Add all WhereLoop objects for a table of the join identified by
** pBuilder->pNew->iTab. That table is guaranteed to be a virtual table.
|
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Changes to src/whereexpr.c.
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** LIKE on all candidate expressions by clearing the isComplete flag
*/
if( c=='A'-1 ) isComplete = 0;
c = sqlite3UpperToLower[c];
}
*pC = c + 1;
}
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** LIKE on all candidate expressions by clearing the isComplete flag
*/
if( c=='A'-1 ) isComplete = 0;
c = sqlite3UpperToLower[c];
}
*pC = c + 1;
}
zCollSeqName = noCase ? "NOCASE" : sqlite3StrBINARY;
pNewExpr1 = sqlite3ExprDup(db, pLeft, 0);
pNewExpr1 = sqlite3PExpr(pParse, TK_GE,
sqlite3ExprAddCollateString(pParse,pNewExpr1,zCollSeqName),
pStr1);
transferJoinMarkings(pNewExpr1, pExpr);
idxNew1 = whereClauseInsert(pWC, pNewExpr1, wtFlags);
testcase( idxNew1==0 );
|
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