3 files changed, 11 insertions, 1 deletions
diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
index 13bf891cea..e284fd71d7 100644
--- a/src/backend/executor/execExpr.c
+++ b/src/backend/executor/execExpr.c
@@ -2287,18 +2287,21 @@ ExecPushExprSlots(ExprState *state, LastAttnumInfo *info)
 	{
 		scratch.opcode = EEOP_INNER_FETCHSOME;
 		scratch.d.fetch.last_var = info->last_inner;
+		scratch.d.fetch.known_desc = NULL;
 		ExprEvalPushStep(state, &scratch);
 	}
 	if (info->last_outer > 0)
 	{
 		scratch.opcode = EEOP_OUTER_FETCHSOME;
 		scratch.d.fetch.last_var = info->last_outer;
+		scratch.d.fetch.known_desc = NULL;
 		ExprEvalPushStep(state, &scratch);
 	}
 	if (info->last_scan > 0)
 	{
 		scratch.opcode = EEOP_SCAN_FETCHSOME;
 		scratch.d.fetch.last_var = info->last_scan;
+		scratch.d.fetch.known_desc = NULL;
 		ExprEvalPushStep(state, &scratch);
 	}
 }
@@ -3250,10 +3253,12 @@ ExecBuildGroupingEqual(TupleDesc ldesc, TupleDesc rdesc,
 	/* push deform steps */
 	scratch.opcode = EEOP_INNER_FETCHSOME;
 	scratch.d.fetch.last_var = maxatt;
+	scratch.d.fetch.known_desc = ldesc;
 	ExprEvalPushStep(state, &scratch);
 
 	scratch.opcode = EEOP_OUTER_FETCHSOME;
 	scratch.d.fetch.last_var = maxatt;
+	scratch.d.fetch.known_desc = rdesc;
 	ExprEvalPushStep(state, &scratch);
 
 	/*
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index c46d65cf93..acd1b97b0e 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -896,6 +896,7 @@ ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupledesc)
 {
 	scanstate->ss_ScanTupleSlot = ExecAllocTableSlot(&estate->es_tupleTable,
 													 tupledesc);
+	scanstate->ps.scandesc = tupledesc;
 }
 
 /* ----------------
diff --git a/src/backend/executor/nodeForeignscan.c b/src/backend/executor/nodeForeignscan.c
index 0084234b35..a2a28b7ec2 100644
--- a/src/backend/executor/nodeForeignscan.c
+++ b/src/backend/executor/nodeForeignscan.c
@@ -186,7 +186,11 @@ ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
 	}
 	else
 	{
-		ExecInitScanTupleSlot(estate, &scanstate->ss, RelationGetDescr(currentRelation));
+		TupleDesc	scan_tupdesc;
+
+		/* don't trust FDWs to return tuples fulfilling NOT NULL constraints */
+		scan_tupdesc = CreateTupleDescCopy(RelationGetDescr(currentRelation));
+		ExecInitScanTupleSlot(estate, &scanstate->ss, scan_tupdesc);
 		/* Node's targetlist will contain Vars with varno = scanrelid */
 		tlistvarno = scanrelid;
 	}