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Overview
| Comment: | Make sure that the sorting-index pre-filter recognizes that a rowid reference might be sortable. This fixes a performance regression. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | Cplusplus-comment |
| Files: | files | file ages | folders |
| SHA1: |
72727b68cd07969165f1f0943cc7e1a2 |
| User & Date: | drh 2014-09-19 02:01:37 |
Context
|
2014-09-19
| ||
| 04:42 | Add the sqlite3VdbeMemClearAndResize() function. Fix a sorting-index prefilter problem. (check-in: 987a7a21 user: drh tags: trunk) | |
| 02:01 | Make sure that the sorting-index pre-filter recognizes that a rowid reference might be sortable. This fixes a performance regression. (Closed-Leaf check-in: 72727b68 user: drh tags: Cplusplus-comment) | |
| 00:43 | Add the sqlite3VdbeMemClearAndResize() interface to be used in place of sqlite3VdbeMemGrow(). A C++ style comment was left in this check-in by mistake, and so it has been moved into a branch to avoid problems in any future bisects on windows. (check-in: 5b9b8987 user: drh tags: Cplusplus-comment) | |
Changes
Changes to src/where.c.
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if( pIndex->bUnordered ) return 0;
if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
for(ii=0; ii<pOB->nExpr; ii++){
Expr *pExpr = sqlite3ExprSkipCollate(pOB->a[ii].pExpr);
if( pExpr->op!=TK_COLUMN ) return 0;
if( pExpr->iTable==iCursor ){
for(jj=0; jj<pIndex->nKeyCol; jj++){
if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
}
}
}
return 0;
}
|
> |
4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 |
if( pIndex->bUnordered ) return 0;
if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
for(ii=0; ii<pOB->nExpr; ii++){
Expr *pExpr = sqlite3ExprSkipCollate(pOB->a[ii].pExpr);
if( pExpr->op!=TK_COLUMN ) return 0;
if( pExpr->iTable==iCursor ){
if( pExpr->iColumn<0 ) return 1;
for(jj=0; jj<pIndex->nKeyCol; jj++){
if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
}
}
}
return 0;
}
|
Changes to test/orderby1.test.
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SELECT (
SELECT 'hardware' FROM (
SELECT 'software' ORDER BY 'firmware' ASC, 'sportswear' DESC
) GROUP BY 1 HAVING length(b)
)
FROM abc;
} {hardware hardware hardware}
finish_test
|
> > > > > > > > > > > > > > |
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SELECT (
SELECT 'hardware' FROM (
SELECT 'software' ORDER BY 'firmware' ASC, 'sportswear' DESC
) GROUP BY 1 HAVING length(b)
)
FROM abc;
} {hardware hardware hardware}
# Here is a test for a query-planner problem reported on the SQLite
# mailing list on 2014-09-18 by "Merike". Beginning with version 3.8.0,
# a separate sort was being used rather than using the single-column
# index. This was due to an oversight in the indexMightHelpWithOrderby()
# routine in where.c.
#
do_execsql_test 7.0 {
CREATE TABLE t7(a,b);
CREATE INDEX t7a ON t7(a);
CREATE INDEX t7ab ON t7(a,b);
EXPLAIN QUERY PLAN
SELECT * FROM t7 WHERE a=?1 ORDER BY rowid;
} {~/ORDER BY/}
finish_test
|