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-rw-r--r--src/backend/utils/adt/selfuncs.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index ce6a626eba2..17fbfa9b410 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -3798,18 +3798,25 @@ estimate_multivariate_bucketsize(PlannerInfo *root, RelOptInfo *inner,
List *hashclauses,
Selectivity *innerbucketsize)
{
- List *clauses = list_copy(hashclauses);
- List *otherclauses = NIL;
- double ndistinct = 1.0;
+ List *clauses;
+ List *otherclauses;
+ double ndistinct;
if (list_length(hashclauses) <= 1)
-
+ {
/*
* Nothing to do for a single clause. Could we employ univariate
* extended stat here?
*/
return hashclauses;
+ }
+ /* "clauses" is the list of hashclauses we've not dealt with yet */
+ clauses = list_copy(hashclauses);
+ /* "otherclauses" holds clauses we are going to return to caller */
+ otherclauses = NIL;
+ /* current estimate of ndistinct */
+ ndistinct = 1.0;
while (clauses != NIL)
{
ListCell *lc;
@@ -3874,12 +3881,13 @@ estimate_multivariate_bucketsize(PlannerInfo *root, RelOptInfo *inner,
group_rel = root->simple_rel_array[relid];
}
else if (group_relid != relid)
-
+ {
/*
* Being in the group forming state we don't need other
* clauses.
*/
continue;
+ }
/*
* We're going to add the new clause to the varinfos list. We