Build HashState's hashkeys expression with the correct parent.

anarazel · anarazel · commit 5f32b29c1819 · 2018-11-07T09:25:54.000-08:00
Previously the expressions were built with the HashJoinState as a parent. That's incorrect. Currently this does not appear to be harmful, but for the upcoming 'slot abstraction' work this proves to be problematic, as the underlying slot types can differ between Hash and HashJoin. It's possible that this already causes a problem, but I've not been able to come up with a scenario. Therefore don't backpatch at this point. Author: Andres Freund Discussion: https://postgr.es/m/20180220224318.gw4oe5jadhpmcdnm@alap3.anarazel.de
diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c
@@ -595,6 +595,7 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 	Hash	   *hashNode;
 	List	   *lclauses;
 	List	   *rclauses;
+	List	   *rhclauses;
 	List	   *hoperators;
 	TupleDesc	outerDesc,
 				innerDesc;
@@ -726,6 +727,7 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 	 */
 	lclauses = NIL;
 	rclauses = NIL;
+	rhclauses = NIL;
 	hoperators = NIL;
 	foreach(l, node->hashclauses)
 	{
@@ -735,13 +737,15 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 												  (PlanState *) hjstate));
 		rclauses = lappend(rclauses, ExecInitExpr(lsecond(hclause->args),
 												  (PlanState *) hjstate));
+		rhclauses = lappend(rhclauses, ExecInitExpr(lsecond(hclause->args),
+												   innerPlanState(hjstate)));
 		hoperators = lappend_oid(hoperators, hclause->opno);
 	}
 	hjstate->hj_OuterHashKeys = lclauses;
 	hjstate->hj_InnerHashKeys = rclauses;
 	hjstate->hj_HashOperators = hoperators;
 	/* child Hash node needs to evaluate inner hash keys, too */
-	((HashState *) innerPlanState(hjstate))->hashkeys = rclauses;
+	((HashState *) innerPlanState(hjstate))->hashkeys = rhclauses;
 
 	hjstate->hj_JoinState = HJ_BUILD_HASHTABLE;
 	hjstate->hj_MatchedOuter = false;
