[#24663] YSQL: Fix foreign key on unique index with different column …

…orders

Summary:
For a foreign key constraint on the unique index of the referenced relation, the function YBCBuildYBTupleIdDescriptor() incorrectly assumes that the order of columns in foreign and unique key constraints would be the same. This leads to incorrect foreign key violation errors and data inconsistency issues when that is not the case (see the added test). Fix it by using the correct attribute number in the index relation.
Jira: DB-13730

Test Plan:
./yb_build.sh --java-test org.yb.pgsql.TestPgForeignKey
./yb_build.sh --java-test org.yb.pgsql.TestPgForeignKeyBatching
./yb_build.sh --java-test org.yb.pgsql.TestPgRegressForeignKey

Reviewers: dmitry

Reviewed By: dmitry

Subscribers: smishra, yql

Differential Revision: https://phorge.dev.yugabyte.com/D39538

src/postgres/src/backend/access/yb_access/yb_scan.c

@@ -990,21 +990,6 @@ YbGetLengthOfKey(ScanKey *key_ptr)
 	return length_of_key;
 }
 
-/*
- * Given a table attribute number, get a corresponding index attribute number.
- * Throw an error if it is not found.
- */
-static AttrNumber
-YbGetIndexAttnum(AttrNumber table_attno, Relation index)
-{
-	for (int i = 0; i < IndexRelationGetNumberOfAttributes(index); ++i)
-	{
-		if (table_attno == index->rd_index->indkey.values[i])
-			return i + 1;
-	}
-	elog(ERROR, "column is not in index");
-}
-
 /*
  * Add ordinary key to ybScan.
  */
@@ -2716,7 +2701,7 @@ YbDmlAppendTargetsAggregate(List *aggrefs, TupleDesc tupdesc, Relation index,
 					 * attribute number to an index-based one.
 					 */
 					if (index && xs_want_itup)
-						attno = YbGetIndexAttnum(attno, index);
+						attno = YbGetIndexAttnum(index, attno);
 					Form_pg_attribute attr = TupleDescAttr(tupdesc, attno - 1);
 					YBCPgTypeAttrs type_attrs = {attr->atttypmod};
 
@@ -3232,7 +3217,7 @@ SysScanDesc ybc_systable_begin_default_scan(Relation relation,
 			 *   must be used for bindings.
 			 */
 			for (int i = 0; i < nkeys; ++i)
-				key[i].sk_attno = YbGetIndexAttnum(key[i].sk_attno, index);
+				key[i].sk_attno = YbGetIndexAttnum(index, key[i].sk_attno);
 		}
 	}
 

src/postgres/src/backend/utils/adt/ri_triggers.c

@@ -276,7 +276,9 @@ YBCBuildYBTupleIdDescriptor(const RI_ConstraintInfo *riinfo, TupleTableSlot *slo
 	TupleDesc source_tupdesc = source_rel->rd_att;
 	for (int i = 0; i < riinfo->nkeys; ++i, ++next_attr)
 	{
-		next_attr->attr_num = using_index ? (i + 1) : riinfo->pk_attnums[i];
+		next_attr->attr_num =
+			using_index ? YbGetIndexAttnum(source_rel, riinfo->pk_attnums[i]) :
+						  riinfo->pk_attnums[i];
 		const int fk_attnum = riinfo->fk_attnums[i];
 		const Oid type_id = TupleDescAttr(slot->tts_tupleDescriptor, fk_attnum - 1)->atttypid;
 		/*

src/postgres/src/backend/utils/misc/pg_yb_utils.c

@@ -5678,3 +5678,19 @@ bool YbUseUnsafeTruncate(Relation rel)
 	return IsYBRelation(rel) &&
 		(IsSystemRelation(rel) || !yb_enable_alter_table_rewrite);
 }
+
+
+/*
+ * Given a table attribute number, get a corresponding index attribute number.
+ * Throw an error if it is not found.
+ */
+AttrNumber
+YbGetIndexAttnum(Relation index, AttrNumber table_attno)
+{
+	for (int i = 0; i < IndexRelationGetNumberOfAttributes(index); ++i)
+	{
+		if (table_attno == index->rd_index->indkey.values[i])
+			return i + 1;
+	}
+	elog(ERROR, "column is not in index");
+}

src/postgres/src/include/pg_yb_utils.h

@@ -1253,6 +1253,8 @@ SortByDir YbGetIndexKeySortOrdering(Relation indexRel);
 
 bool YbUseUnsafeTruncate(Relation rel);
 
+extern AttrNumber YbGetIndexAttnum(Relation index, AttrNumber table_attno);
+
 extern bool yb_ysql_conn_mgr_superuser_existed;
 
 #endif /* PG_YB_UTILS_H */

src/postgres/src/test/regress/expected/yb_foreign_key.out

@@ -673,3 +673,16 @@ ERROR:  insert or update on table "child_2" violates foreign key constraint "chi
 DETAIL:  Key (v)=(1010002) is not present in table "parent".
 UPDATE child_1 SET v = v * 2 WHERE k < 5001;
 UPDATE child_2 SET v = (v - 1000000) * 2 + 1000000 WHERE k < 5001;
+-- Test foreign key on unique index such that column orders in fk and unique constraints differ.
+CREATE TABLE pk(id INT, name INT, add INT, PRIMARY KEY (id, name, add), UNIQUE (name, id));
+CREATE TABLE fk(id INT, name INT, FOREIGN KEY(id, name) REFERENCES pk(id, name));
+INSERT INTO pk VALUES (1, 500, 1000);
+INSERT INTO fk VALUES (1, 500);
+INSERT INTO fk VALUES (500, 1); -- should fail
+ERROR:  insert or update on table "fk" violates foreign key constraint "fk_id_name_fkey"
+DETAIL:  Key (id, name)=(500, 1) is not present in table "pk".
+SELECT * from fk;
+ id | name 
+----+------
+  1 |  500
+(1 row)

src/postgres/src/test/regress/sql/yb_foreign_key.sql

@@ -419,3 +419,11 @@ UPDATE child_2 SET v = (v - 1000000) * 2 + 1000000 WHERE k <= 5001; -- should fa
 
 UPDATE child_1 SET v = v * 2 WHERE k < 5001;
 UPDATE child_2 SET v = (v - 1000000) * 2 + 1000000 WHERE k < 5001;
+
+-- Test foreign key on unique index such that column orders in fk and unique constraints differ.
+CREATE TABLE pk(id INT, name INT, add INT, PRIMARY KEY (id, name, add), UNIQUE (name, id));
+CREATE TABLE fk(id INT, name INT, FOREIGN KEY(id, name) REFERENCES pk(id, name));
+INSERT INTO pk VALUES (1, 500, 1000);
+INSERT INTO fk VALUES (1, 500);
+INSERT INTO fk VALUES (500, 1); -- should fail
+SELECT * from fk;