diff options
Diffstat (limited to 'src/backend/statistics/dependencies.c')
| -rw-r--r-- | src/backend/statistics/dependencies.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c index fb958e1b0a5..159ddb87233 100644 --- a/src/backend/statistics/dependencies.c +++ b/src/backend/statistics/dependencies.c @@ -900,7 +900,13 @@ find_strongest_dependency(StatisticExtInfo * stats, MVDependencies * dependencie /* * dependencies_clauselist_selectivity - * Attempt to estimate selectivity using functional dependency statistics + * Return the estimated selectivity of the given clauses using + * functional dependency statistics, or 1.0 if no useful functional + * dependency statistic exists. + * + * 'estimatedclauses' is an output argument that gets a bit set corresponding + * to the (zero-based) list index of clauses that are included in the + * estimated selectivity. * * Given equality clauses on attributes (a,b) we find the strongest dependency * between them, i.e. either (a=>b) or (b=>a). Assuming (a=>b) is the selected @@ -935,7 +941,6 @@ dependencies_clauselist_selectivity(PlannerInfo *root, AttrNumber *list_attnums; int listidx; - /* check if there's any stats that might be useful for us. */ if (!has_stats_of_kind(rel->statlist, STATS_EXT_DEPENDENCIES)) return 1.0; |