diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 7e2b2e3..7139c8b 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -105,6 +105,7 @@ typedef struct RI_ConstraintInfo
 	NameData	conname;		/* name of the FK constraint */
 	Oid			pk_relid;		/* referenced relation */
 	Oid			fk_relid;		/* referencing relation */
+	Oid			conparentid;	/* parent constraint */
 	char		confupdtype;	/* foreign key's ON UPDATE action */
 	char		confdeltype;	/* foreign key's ON DELETE action */
 	char		confmatchtype;	/* foreign key's match type */
@@ -221,6 +222,7 @@ static void ri_ReportViolation(const RI_ConstraintInfo *riinfo,
 							   Relation pk_rel, Relation fk_rel,
 							   TupleTableSlot *violatorslot, TupleDesc tupdesc,
 							   int queryno, bool partgone) pg_attribute_noreturn();
+static Oid ri_GetParentConstOid(Oid constraintOid);
 
 
 /*
@@ -366,6 +368,14 @@ RI_FKey_check(TriggerData *trigdata)
 		querysep = "WHERE";
 		for (int i = 0; i < riinfo->nkeys; i++)
 		{
+
+			/*
+			* We share the same plan among all relations in a partition
+			* hierarchy.  The plan is guaranteed to be compatible since all of
+			* the member relations are guaranteed to have the equivalent set
+			* of foreign keys in fk_attnums[].
+			*/
+
 			Oid			pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
 			Oid			fk_type = RIAttType(fk_rel, riinfo->fk_attnums[i]);
 
@@ -1904,7 +1914,16 @@ ri_BuildQueryKey(RI_QueryKey *key, const RI_ConstraintInfo *riinfo,
 	/*
 	 * We assume struct RI_QueryKey contains no padding bytes, else we'd need
 	 * to use memset to clear them.
+	 * If this constraint has conparentid, we use it instead of constraint_id.
+	 * Because constraints which has same conparentid are able to share SPI
+	 * Plan, so this is useful to reduce hashtable size.
+	 * Consider sub-partitioning and get the top comparentid.
 	 */
+
+	while (riinfo->conparentid != InvalidOid) {
+		riinfo = ri_LoadConstraintInfo(riinfo->conparentid); 
+	}
+
 	key->constr_id = riinfo->constraint_id;
 	key->constr_queryno = constr_queryno;
 }
@@ -2059,6 +2078,7 @@ ri_LoadConstraintInfo(Oid constraintOid)
 	riinfo->confupdtype = conForm->confupdtype;
 	riinfo->confdeltype = conForm->confdeltype;
 	riinfo->confmatchtype = conForm->confmatchtype;
+	riinfo->conparentid = conForm->conparentid;
 
 	DeconstructFkConstraintRow(tup,
 							   &riinfo->nkeys,