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Overview
| Comment: | Bug fixes in the ORDER BY optimizer. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | qp-enhancements |
| Files: | files | file ages | folders |
| SHA1: |
301bbee4045aa169e29fb4fb75743b71 |
| User & Date: | drh 2012-10-08 19:41:38.447 |
Context
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2012-10-08
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| 20:27 | Further tweaks to the ORDER BY optimizer, to fix a bug and to get the optimizer to recognize some additional cases. (check-in: bcb4f26247 user: drh tags: qp-enhancements) | |
| 19:41 | Bug fixes in the ORDER BY optimizer. (check-in: 301bbee404 user: drh tags: qp-enhancements) | |
| 18:23 | Continued refactoring of the ORDER BY optimization logic. This check-in is close to working, but it still has issues. A few test cases fail. (check-in: adbdc663f3 user: drh tags: qp-enhancements) | |
Changes
Changes to src/where.c.
| ︙ | ︙ | |||
2799 2800 2801 2802 2803 2804 2805 | struct ExprList_item *pOBItem;/* A term of the ORDER BY clause */ Table *pTab = pIdx->pTable; /* Table that owns index pIdx */ ExprList *pOrderBy; /* The ORDER BY clause */ Parse *pParse = p->pParse; /* Parser context */ sqlite3 *db = pParse->db; /* Database connection */ int nPriorSat; /* ORDER BY terms satisfied by outer loops */ int seenRowid = 0; /* True if an ORDER BY rowid term is seen */ | | > > > > > | > > > > | > > > > | 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 |
struct ExprList_item *pOBItem;/* A term of the ORDER BY clause */
Table *pTab = pIdx->pTable; /* Table that owns index pIdx */
ExprList *pOrderBy; /* The ORDER BY clause */
Parse *pParse = p->pParse; /* Parser context */
sqlite3 *db = pParse->db; /* Database connection */
int nPriorSat; /* ORDER BY terms satisfied by outer loops */
int seenRowid = 0; /* True if an ORDER BY rowid term is seen */
int uniqueNotNull; /* pIdx is UNIQUE with all terms are NOT NULL */
if( p->i==0 ){
nPriorSat = 0;
}else{
nPriorSat = p->aLevel[p->i-1].plan.nOBSat;
if( (p->aLevel[p->i-1].plan.wsFlags & WHERE_ORDERED)==0 ){
/* This loop cannot be ordered unless the next outer loop is
** also ordered */
return nPriorSat;
}
if( OptimizationDisabled(db, SQLITE_OrderByIdxJoin) ){
/* Only look at the outer-most loop if the OrderByIdxJoin
** optimization is disabled */
return nPriorSat;
}
}
pOrderBy = p->pOrderBy;
assert( pOrderBy!=0 );
if( pIdx->bUnordered ){
/* Hash indices (indicated by the "unordered" tag on sqlite_stat1) cannot
** be used for sorting */
return nPriorSat;
}
nTerm = pOrderBy->nExpr;
uniqueNotNull = pIdx->onError!=OE_None;
assert( nTerm>0 );
/* Argument pIdx must either point to a 'real' named index structure,
** or an index structure allocated on the stack by bestBtreeIndex() to
** represent the rowid index that is part of every table. */
|
| ︙ | ︙ | |||
2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 |
if( iColumn<0 ){
seenRowid = 1;
break;
}else if( pTab->aCol[iColumn].notNull==0 ){
uniqueNotNull = 0;
}
}
*pbRev = sortOrder & 1;
/* If there was an "ORDER BY rowid" term that matched, or it is only
** possible for a single row from this table to match, then skip over
** any additional ORDER BY terms dealing with this table.
*/
if( seenRowid || (uniqueNotNull && i>=pIdx->nColumn) ){
| > > > > > > | 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 |
if( iColumn<0 ){
seenRowid = 1;
break;
}else if( pTab->aCol[iColumn].notNull==0 ){
uniqueNotNull = 0;
}
}
/* If we have not found at least one ORDER BY term that matches the
** index, then show no progress. */
if( pOBItem==&pOrderBy->a[nPriorSat] ) return nPriorSat;
/* Return the necessary scan order back to the caller */
*pbRev = sortOrder & 1;
/* If there was an "ORDER BY rowid" term that matched, or it is only
** possible for a single row from this table to match, then skip over
** any additional ORDER BY terms dealing with this table.
*/
if( seenRowid || (uniqueNotNull && i>=pIdx->nColumn) ){
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| ︙ | ︙ |