diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/where.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/src/where.c b/src/where.c index 2573faff2..1be1b20a4 100644 --- a/src/where.c +++ b/src/where.c @@ -2247,12 +2247,16 @@ static void bestVirtualIndex(WhereBestIdx *p){ assert( sqlite3GetVTable(pParse->db, pTab) ); /* Try once or twice. On the first attempt, allow IN optimizations. - ** If an IN optimization is accepted, but does not set the - ** pInfo->aConstrainUsage.omit flag, then it will not work (because it - ** will allow duplicate rows in the result set) so try again with - ** IN optimizations disabled. + ** If an IN optimization is accepted by the virtual table xBestIndex + ** method, but the pInfo->aConstrainUsage.omit flag is not set, then + ** the query will not work because it might allow duplicate rows in + ** output. In that case, run the xBestIndex method a second time + ** without the IN constraints. Usually this loop only runs once. + ** The loop will exit using a "break" statement. */ - for(bAllowIN=1; bAllowIN>=0; bAllowIN--){ + for(bAllowIN=1; 1; bAllowIN--){ + assert( bAllowIN==0 || bAllowIN==1 ); + /* Set the aConstraint[].usable fields and initialize all ** output variables to zero. ** |