diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index bb65fb1e0a..bd7aba63c7 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -984,6 +984,46 @@ get_relation_constraint_attnos(Oid relid, const char *conname,
 	return conattnos;
 }
 
+/*
+ * Detaches the constraint(s) associated with the given index in the
+ * given relation.
+ * Returns the number of detached constraints or 0 if no such index is catalogued.
+ */
+int
+detach_relation_idx_constraints(Oid relationId, Oid indexId)
+{
+	Relation	pg_constraint;
+	SysScanDesc scan;
+	ScanKeyData key;
+	HeapTuple	tuple;
+	int			count = 0;
+
+	pg_constraint = table_open(ConstraintRelationId, AccessShareLock);
+
+	ScanKeyInit(&key,
+				Anum_pg_constraint_conrelid,
+				BTEqualStrategyNumber,
+				F_OIDEQ,
+				ObjectIdGetDatum(relationId));
+	scan = systable_beginscan(pg_constraint, ConstraintRelidTypidNameIndexId,
+							  true, NULL, 1, &key);
+	while ((tuple = systable_getnext(scan)) != NULL)
+	{
+		Form_pg_constraint constrForm;
+
+		constrForm = (Form_pg_constraint) GETSTRUCT(tuple);
+		if (constrForm->conindid == indexId)
+		{
+			ConstraintSetParentConstraint(constrForm->oid, InvalidOid, InvalidOid);
+			count++;
+		}
+	}
+	systable_endscan(scan);
+
+	table_close(pg_constraint, AccessShareLock);
+	return count;
+}
+
 /*
  * Return the OID of the constraint associated with the given index in the
  * given relation; or InvalidOid if no such index is catalogued.
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 9be04c8a1e..4ecf74f851 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -18578,7 +18578,6 @@ DetachPartitionFinalize(Relation rel, Relation partRel, bool concurrent,
 	{
 		Oid			idxid = lfirst_oid(cell);
 		Relation	idx;
-		Oid			constrOid;
 
 		if (!has_superclass(idxid))
 			continue;
@@ -18590,10 +18589,7 @@ DetachPartitionFinalize(Relation rel, Relation partRel, bool concurrent,
 		IndexSetParentIndex(idx, InvalidOid);
 
 		/* If there's a constraint associated with the index, detach it too */
-		constrOid = get_relation_idx_constraint_oid(RelationGetRelid(partRel),
-													idxid);
-		if (OidIsValid(constrOid))
-			ConstraintSetParentConstraint(constrOid, InvalidOid, InvalidOid);
+		detach_relation_idx_constraints(RelationGetRelid(partRel), idxid);
 
 		index_close(idx, NoLock);
 	}
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index e7d967f137..a1933c5c53 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -257,6 +257,7 @@ extern Bitmapset *get_relation_constraint_attnos(Oid relid, const char *conname,
 												 bool missing_ok, Oid *constraintOid);
 extern Oid	get_domain_constraint_oid(Oid typid, const char *conname, bool missing_ok);
 extern Oid	get_relation_idx_constraint_oid(Oid relationId, Oid indexId);
+extern int	detach_relation_idx_constraints(Oid relationId, Oid indexId);
 
 extern Bitmapset *get_primary_key_attnos(Oid relid, bool deferrableOk,
 										 Oid *constraintOid);