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| author | drh <drh@noemail.net> | 2011-07-13 18:31:10 +0000 |
|---|---|---|
| committer | drh <drh@noemail.net> | 2011-07-13 18:31:10 +0000 |
| commit | bf4ec555fa99ce2968f8a309dab38e239bab6abc (patch) | |
| tree | 5125d8f3d602352addacf85b5deac1b772ae73b8 /src | |
| parent | d0cdf012a2cfb309a57c1d3bf26f7045c7ce853f (diff) | |
| download | sqlite-bf4ec555fa99ce2968f8a309dab38e239bab6abc.tar.gz sqlite-bf4ec555fa99ce2968f8a309dab38e239bab6abc.zip | |
Do not try to use STAT2 to refine the row estimate of a query that
uses a unique or nearly-unique index.
FossilOrigin-Name: efffc49baf38698ed3de05d16b4261bf405d42d7
Diffstat (limited to 'src')
| -rw-r--r-- | src/where.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/where.c b/src/where.c index bb3bee357..d31223286 100644 --- a/src/where.c +++ b/src/where.c @@ -3111,12 +3111,13 @@ static void bestBtreeIndex( } #ifdef SQLITE_ENABLE_STAT2 - /* If the constraint is of the form x=VALUE and histogram + /* If the constraint is of the form x=VALUE or x IN (E1,E2,...) + ** and we do not think that values of x are unique and if histogram ** data is available for column x, then it might be possible ** to get a better estimate on the number of rows based on ** VALUE and how common that value is according to the histogram. */ - if( nRow>(double)1 && nEq==1 && pFirstTerm!=0 ){ + if( nRow>(double)1 && nEq==1 && pFirstTerm!=0 && aiRowEst[1]>1 ){ if( pFirstTerm->eOperator & (WO_EQ|WO_ISNULL) ){ testcase( pFirstTerm->eOperator==WO_EQ ); testcase( pFirstTerm->eOperator==WO_ISNULL ); |