diff options
Diffstat (limited to 'src/backend/utils/adt')
| -rw-r--r-- | src/backend/utils/adt/selfuncs.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 1c9b3c60b9d..a56ac81042a 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -15,7 +15,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.91 2001/05/27 17:37:48 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.92 2001/06/05 05:26:04 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1132,10 +1132,12 @@ eqjoinsel(PG_FUNCTION_ARGS) totalsel2 += otherfreq2 * (otherfreq1 + unmatchfreq1) / (nd1 - nmatches); /* - * For robustness, we average the two estimates. (Can a case - * be made for taking the min or max instead?) + * Use the smaller of the two estimates. This can be justified + * in essentially the same terms as given below for the no-stats + * case: to a first approximation, we are estimating from the + * point of view of the relation with smaller nd. */ - selec = (totalsel1 + totalsel2) * 0.5; + selec = (totalsel1 < totalsel2) ? totalsel1 : totalsel2; } else { |