1 files changed, 56 insertions, 6 deletions

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 4d0e18fb145..2d66639a209 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -69,6 +69,7 @@
 #include "pgstat.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
+#include "utils/array.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/inval.h"
@@ -2004,6 +2005,60 @@ RelationClearMissing(Relation rel)
 }
 
 /*
+ * StoreAttrMissingVal
+ *
+ * Set the missing value of a single attribute.
+ */
+void
+StoreAttrMissingVal(Relation rel, AttrNumber attnum, Datum missingval)
+{
+	Datum		valuesAtt[Natts_pg_attribute] = {0};
+	bool		nullsAtt[Natts_pg_attribute] = {0};
+	bool		replacesAtt[Natts_pg_attribute] = {0};
+	Relation	attrrel;
+	Form_pg_attribute attStruct;
+	HeapTuple	atttup,
+				newtup;
+
+	/* This is only supported for plain tables */
+	Assert(rel->rd_rel->relkind == RELKIND_RELATION);
+
+	/* Fetch the pg_attribute row */
+	attrrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	atttup = SearchSysCache2(ATTNUM,
+							 ObjectIdGetDatum(RelationGetRelid(rel)),
+							 Int16GetDatum(attnum));
+	if (!HeapTupleIsValid(atttup))	/* shouldn't happen */
+		elog(ERROR, "cache lookup failed for attribute %d of relation %u",
+			 attnum, RelationGetRelid(rel));
+	attStruct = (Form_pg_attribute) GETSTRUCT(atttup);
+
+	/* Make a one-element array containing the value */
+	missingval = PointerGetDatum(construct_array(&missingval,
+												 1,
+												 attStruct->atttypid,
+												 attStruct->attlen,
+												 attStruct->attbyval,
+												 attStruct->attalign));
+
+	/* Update the pg_attribute row */
+	valuesAtt[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(true);
+	replacesAtt[Anum_pg_attribute_atthasmissing - 1] = true;
+
+	valuesAtt[Anum_pg_attribute_attmissingval - 1] = missingval;
+	replacesAtt[Anum_pg_attribute_attmissingval - 1] = true;
+
+	newtup = heap_modify_tuple(atttup, RelationGetDescr(attrrel),
+							   valuesAtt, nullsAtt, replacesAtt);
+	CatalogTupleUpdate(attrrel, &newtup->t_self, newtup);
+
+	/* clean up */
+	ReleaseSysCache(atttup);
+	table_close(attrrel, RowExclusiveLock);
+}
+
+/*
  * SetAttrMissing
  *
  * Set the missing value of a single attribute. This should only be used by
@@ -2330,13 +2385,8 @@ AddRelationNewConstraints(Relation rel,
 			 castNode(Const, expr)->constisnull))
 			continue;
 
-		/* If the DEFAULT is volatile we cannot use a missing value */
-		if (colDef->missingMode &&
-			contain_volatile_functions_after_planning((Expr *) expr))
-			colDef->missingMode = false;
-
 		defOid = StoreAttrDefault(rel, colDef->attnum, expr, is_internal,
-								  colDef->missingMode);
+								  false);
 
 		cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
 		cooked->contype = CONSTR_DEFAULT;