I came across a couple of places in the planner that are checking
for nonempty havingQual; but since these bits run after
const-simplification of the HAVING clause, that produces the wrong
answer for a constant-true HAVING clause (which'll be folded to
empty). Correct code is to check root->hasHavingQual instead.
These mistakes only affect cost estimates, and they're sufficiently
corner cases that it'd be hard even to devise a reliable test case
showing a different plan choice. So I'm not very excited about this,
and am thinking of committing only to HEAD.
regards, tom lane
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index d98709e5e8..8d7500abfb 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -3357,7 +3357,7 @@ estimate_path_cost_size(PlannerInfo *root,
* Get the retrieved_rows and rows estimates. If there are HAVING
* quals, account for their selectivity.
*/
- if (root->parse->havingQual)
+ if (root->hasHavingQual)
{
/* Factor in the selectivity of the remotely-checked quals */
retrieved_rows =
@@ -3405,7 +3405,7 @@ estimate_path_cost_size(PlannerInfo *root,
run_cost += cpu_tuple_cost * numGroups;
/* Account for the eval cost of HAVING quals, if any */
- if (root->parse->havingQual)
+ if (root->hasHavingQual)
{
QualCost remote_cost;
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 8fc28007f5..4ddaed31a4 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -2575,7 +2575,7 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
if (parse->hasAggs ||
parse->groupClause ||
parse->groupingSets ||
- parse->havingQual ||
+ root->hasHavingQual ||
parse->distinctClause ||
parse->sortClause ||
has_multiple_baserels(root))
