Build HashState's hashkeys expression with the correct parent.

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
index 5922e60eed64e6cb4b49aae476c4ab9a20809269..d017bbfbd33fcaeca09bd0b044baa74d0428ffc5 100644 (file)
--- 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;