Re-disallow Memoize for parameterized nested loops with join filters

david-rowley · david-rowley · commit 74f770ef202f · 2024-01-22T22:45:33.000+13:00
This was previously fixed in 9e21537 but got broken again as a result of 2489d76. It seems that commit causes ppi_clauses to contain duplicate clauses and it's no longer safe to check the list_length of that list to determine if there are join conditions other than what's mentioned in ppi_clauses. Here we adjust the check to count the distinct rinfo_serial mentioned in ppi_clauses. We expect that extra->restrictlist won't have duplicate rinfo_serials. Reported-by: Amadeo Gallardo Author: Richard Guo Discussion: https://postgr.es/m/CADFREbW-BLJd7-a5J%2B5wjVumeFG1ByXiSOFzMtkmY_SDWckTxw%40mail.gmail.com Backpatch-through: 16, where 2489d76 was introduced.
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
@@ -651,7 +651,7 @@ get_memoize_path(PlannerInfo *root, RelOptInfo *innerrel,
 	 */
 	if (extra->inner_unique &&
 		(inner_path->param_info == NULL ||
-		 list_length(inner_path->param_info->ppi_clauses) <
+		 bms_num_members(inner_path->param_info->ppi_serials) <
 		 list_length(extra->restrictlist)))
 		return NULL;
 
