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Overview
| Comment: | When an index completely covers a table, it can be used as a covering index even if columns past the 63rd column are indexed and accessed. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
3e9ed1aea43e8ce2eb74bb845ea2c05b |
| User & Date: | drh 2016-02-24 17:18:51 |
| Original Comment: | When an index complete covers a table, it can be used as a covering index even if columns past the 63rd column are indexed and accessed. |
References
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2016-02-24
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| 20:16 | Extend [3e9ed1ae] so that covering indexes on WITHOUT ROWID tables are also identified. (check-in: e721975f user: dan tags: trunk) | |
Context
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2016-02-24
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| 19:57 | Change a char* to const char* in order to suppress some harmless compiler warnings. (check-in: 56f62e34 user: drh tags: trunk) | |
| 17:18 | When an index completely covers a table, it can be used as a covering index even if columns past the 63rd column are indexed and accessed. (check-in: 3e9ed1ae user: drh tags: trunk) | |
| 16:14 | Fix a problem with handling identifiers that start with "x" if SQLITE_OMIT_BLOB_LITERAL is defined. (check-in: b65217c6 user: dan tags: trunk) | |
| 15:43 | Identify indexes that completely cover their table. (Closed-Leaf check-in: 71d488b5 user: drh tags: covering-index) | |
Changes
Changes to src/build.c.
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i++;
}
}
assert( i==pIndex->nColumn );
}else{
pIndex->aiColumn[i] = XN_ROWID;
pIndex->azColl[i] = sqlite3StrBINARY;
}
sqlite3DefaultRowEst(pIndex);
if( pParse->pNewTable==0 ) estimateIndexWidth(pIndex);
if( pTab==pParse->pNewTable ){
/* This routine has been called to create an automatic index as a
** result of a PRIMARY KEY or UNIQUE clause on a column definition, or
|
> > > > > > > > > > > |
3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 |
i++;
}
}
assert( i==pIndex->nColumn );
}else{
pIndex->aiColumn[i] = XN_ROWID;
pIndex->azColl[i] = sqlite3StrBINARY;
/* If this index contains every column of its table, then mark
** it as a covering index */
if( pTblName!=0 && pIndex->nColumn>=pTab->nCol ){
pIndex->isCovering = 1;
for(j=0; j<pTab->nCol; j++){
if( j==pTab->iPKey ) continue;
if( sqlite3ColumnOfIndex(pIndex,j)>=0 ) continue;
pIndex->isCovering = 0;
break;
}
}
}
sqlite3DefaultRowEst(pIndex);
if( pParse->pNewTable==0 ) estimateIndexWidth(pIndex);
if( pTab==pParse->pNewTable ){
/* This routine has been called to create an automatic index as a
** result of a PRIMARY KEY or UNIQUE clause on a column definition, or
|