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Overview
| Comment: | Attempt the constant propagation optimization on any WHERE clause that has a top-level AND operator, even if the query is not a join. This is an attempt to partially address the concern raised in forum post 830d37b928. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
e994c9f29f7a561dd5f30573865b0f79 |
| User & Date: | drh 2021-05-14 14:26:57 |
Context
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2021-05-14
| ||
| 15:37 | Avoid adding superfluous virtual WHERE clause terms that might arise due to the constant propagation optimization. (check-in: cf63abbe user: drh tags: trunk) | |
| 14:26 | Attempt the constant propagation optimization on any WHERE clause that has a top-level AND operator, even if the query is not a join. This is an attempt to partially address the concern raised in forum post 830d37b928. (check-in: e994c9f2 user: drh tags: trunk) | |
| 13:32 | Fix an over-length source code comment in whereexpr.c. No logic changes. (check-in: af5eb902 user: drh tags: trunk) | |
Changes
Changes to src/select.c.
| ︙ | ︙ | |||
4465 4466 4467 4468 4469 4470 4471 |
** Find all terms of COLUMN=VALUE or VALUE=COLUMN in pExpr where VALUE
** is a constant expression and where the term must be true because it
** is part of the AND-connected terms of the expression. For each term
** found, add it to the pConst structure.
*/
static void findConstInWhere(WhereConst *pConst, Expr *pExpr){
Expr *pRight, *pLeft;
| | | 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 |
** Find all terms of COLUMN=VALUE or VALUE=COLUMN in pExpr where VALUE
** is a constant expression and where the term must be true because it
** is part of the AND-connected terms of the expression. For each term
** found, add it to the pConst structure.
*/
static void findConstInWhere(WhereConst *pConst, Expr *pExpr){
Expr *pRight, *pLeft;
if( NEVER(pExpr==0) ) return;
if( ExprHasProperty(pExpr, EP_FromJoin) ) return;
if( pExpr->op==TK_AND ){
findConstInWhere(pConst, pExpr->pRight);
findConstInWhere(pConst, pExpr->pLeft);
return;
}
if( pExpr->op!=TK_EQ ) return;
|
| ︙ | ︙ | |||
6324 6325 6326 6327 6328 6329 6330 | #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(). */ | | > | 6324 6325 6326 6327 6328 6329 6330 6331 6332 6333 6334 6335 6336 6337 6338 6339 |
#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( p->pWhere!=0
&& p->pWhere->op==TK_AND
&& 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);
|
| ︙ | ︙ |