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Overview
| Comment: | Factor an invariant out the loop termination condition for the ORDER BY satisfied-by-index analyzer routine. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
545bb33688663066cf3f09e4cdc4d5cf |
| User & Date: | drh 2012-10-02 01:46:48 |
Context
|
2012-10-02
| ||
| 14:11 | Only continue an ORDER BY optimization into inner loops if the equality constraints on the inner loop match terms of an outer ordered index that are actually used by the ORDER BY clause. check-in: b0e7b4df user: drh tags: trunk | |
| 01:46 | Factor an invariant out the loop termination condition for the ORDER BY satisfied-by-index analyzer routine. check-in: 545bb336 user: drh tags: trunk | |
| 01:25 | Make sure the outer loop cursor numbers are recorded in time for them to be used by the ORDER BY optimizer. check-in: 351dc8d9 user: drh tags: trunk | |
Changes
Changes to src/where.c.
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** the index.
**
** Note that indices have pIdx->nColumn regular columns plus
** one additional column containing the rowid. The rowid column
** of the index is also allowed to match against the ORDER BY
** clause.
*/
for(i=0,j=nPriorSat,pTerm=&pOrderBy->a[j]; j<nTerm && i<=pIdx->nColumn; i++){
Expr *pExpr; /* The expression of the ORDER BY pTerm */
CollSeq *pColl; /* The collating sequence of pExpr */
int termSortOrder; /* Sort order for this term */
int iColumn; /* The i-th column of the index. -1 for rowid */
int iSortOrder; /* 1 for DESC, 0 for ASC on the i-th index term */
const char *zColl; /* Name of the collating sequence for i-th index term */
pExpr = pTerm->pExpr;
if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
/* Can not use an index sort on anything that is not a column in the
** left-most table of the FROM clause */
break;
}
pColl = sqlite3ExprCollSeq(pParse, pExpr);
|
| > |
2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 |
** the index.
**
** Note that indices have pIdx->nColumn regular columns plus
** one additional column containing the rowid. The rowid column
** of the index is also allowed to match against the ORDER BY
** clause.
*/
for(i=0,j=nPriorSat,pTerm=&pOrderBy->a[j]; j<nTerm; i++){
Expr *pExpr; /* The expression of the ORDER BY pTerm */
CollSeq *pColl; /* The collating sequence of pExpr */
int termSortOrder; /* Sort order for this term */
int iColumn; /* The i-th column of the index. -1 for rowid */
int iSortOrder; /* 1 for DESC, 0 for ASC on the i-th index term */
const char *zColl; /* Name of the collating sequence for i-th index term */
assert( i<=pIdx->nColumn );
pExpr = pTerm->pExpr;
if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
/* Can not use an index sort on anything that is not a column in the
** left-most table of the FROM clause */
break;
}
pColl = sqlite3ExprCollSeq(pParse, pExpr);
|