Fix planner's failure to identify multiple hashable ScalarArrayOpExprs

david-rowley · david-rowley · commit b68f664bb024 · 2025-04-02T11:58:37.000+13:00
50e17ad (v14) and 29f45e2 (v15) made it so the planner could identify IN and NOT IN clauses which have Const lists as right-hand arguments and when an appropriate hash function is available for the data types, mark the ScalarArrayOpExpr as hashable so the executor could execute it more optimally by building and probing a hash table during expression evaluation. These commits both worked correctly when there was only a single ScalarArrayOpExpr in the given expression being processed by the planner, but when there were multiple, only the first was checked and any subsequent ones were not identified, which resulted in less optimal expression evaluation during query execution for all but the first found ScalarArrayOpExpr. Backpatch to 14, where 50e17ad was introduced. Author: David Geier <geidav.pg@gmail.com> Discussion: https://postgr.es/m/29a76f51-97b0-4c07-87b7-ec8e3b5345c9@gmail.com Backpatch-through: 14
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
@@ -2228,7 +2228,7 @@ convert_saop_to_hashed_saop_walker(Node *node, void *context)
 				/* Looks good. Fill in the hash functions */
 				saop->hashfuncid = lefthashfunc;
 			}
-			return true;
+			return false;
 		}
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -2228,7 +2228,7 @@ convert_saop_to_hashed_saop_walker(Node node, void context)`
`2228`	`2228`	`/* Looks good. Fill in the hash functions */`
`2229`	`2229`	`saop->hashfuncid = lefthashfunc;`
`2230`	`2230`	`}`
`2231`		`- return true;`
	`2231`	`+ return false;`
`2232`	`2232`	`}`
`2233`	`2233`	`}`
`2234`	`2234`