diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/analyze.c | 10 | ||||
| -rw-r--r-- | src/sqliteInt.h | 1 | ||||
| -rw-r--r-- | src/where.c | 5 |
3 files changed, 15 insertions, 1 deletions
diff --git a/src/analyze.c b/src/analyze.c index a7a8b6d66..a07f1939c 100644 --- a/src/analyze.c +++ b/src/analyze.c @@ -1556,6 +1556,16 @@ static void decodeIntArray( while( z[0]!=0 && z[0]!=' ' ) z++; while( z[0]==' ' ) z++; } + + /* Set the bLowQual flag if the peak number of rows obtained + ** from a full equality match is so large that a full table scan + ** seems likely to be faster than using the index. + */ + if( aLog[0] > 66 /* Index has more than 100 rows */ + && aLog[0] <= aLog[nOut-1] /* And only a single value seen */ + ){ + pIndex->bLowQual = 1; + } } } diff --git a/src/sqliteInt.h b/src/sqliteInt.h index 75ac749c0..79a36e060 100644 --- a/src/sqliteInt.h +++ b/src/sqliteInt.h @@ -2766,6 +2766,7 @@ struct Index { unsigned isCovering:1; /* True if this is a covering index */ unsigned noSkipScan:1; /* Do not try to use skip-scan if true */ unsigned hasStat1:1; /* aiRowLogEst values come from sqlite_stat1 */ + unsigned bLowQual:1; /* sqlite_stat1 says this is a low-quality index */ unsigned bNoQuery:1; /* Do not use this index to optimize queries */ unsigned bAscKeyBug:1; /* True if the bba7b69f9849b5bf bug applies */ unsigned bHasVCol:1; /* Index references one or more VIRTUAL columns */ diff --git a/src/where.c b/src/where.c index bffca3413..4ff2815ba 100644 --- a/src/where.c +++ b/src/where.c @@ -2973,7 +2973,10 @@ static int whereLoopAddBtreeIndex( assert( pNew->u.btree.nBtm==0 ); opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE|WO_ISNULL|WO_IS; } - if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE); + if( pProbe->bUnordered || pProbe->bLowQual ){ + if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE); + if( pProbe->bLowQual ) opMask &= ~(WO_EQ|WO_IN|WO_IS); + } assert( pNew->u.btree.nEq<pProbe->nColumn ); assert( pNew->u.btree.nEq<pProbe->nKeyCol |