Fix assertion with relation using REPLICA IDENTITY FULL in subscriber

In a logical replication subscriber, a table using REPLICA IDENTITY FULL
which has a primary key would try to use the primary key's index
available to scan for a tuple, but an assertion only assumed as correct
the case of an index associated to REPLICA IDENTITY USING INDEX.  This
commit corrects the assertion so as the use of a primary key index is a
valid case.

Reported-by: Dilip Kumar
Analyzed-by: Dilip Kumar
Author: Euler Taveira
Reviewed-by: Michael Paquier, Masahiko Sawada
Discussion: https://postgr.es/m/CAFiTN-u64S5bUiPL1q5kwpHNd0hRnf1OE-bzxNiOs5zo84i51w@mail.gmail.com
Backpatch-through: 10

src/backend/executor/execReplication.c

@@ -57,7 +57,8 @@ build_replindex_scan_key(ScanKey skey, Relation rel, Relation idxrel,
 	int2vector *indkey = &idxrel->rd_index->indkey;
 	bool		hasnulls = false;
 
-	Assert(RelationGetReplicaIndex(rel) == RelationGetRelid(idxrel));
+	Assert(RelationGetReplicaIndex(rel) == RelationGetRelid(idxrel) ||
+		   RelationGetPrimaryKeyIndex(rel) == RelationGetRelid(idxrel));
 
 	indclassDatum = SysCacheGetAttr(INDEXRELID, idxrel->rd_indextuple,
 									Anum_pg_index_indclass, &isnull);

src/test/subscription/t/001_rep_changes.pl

@@ -34,6 +34,10 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE TABLE tab_include (a int, b text, CONSTRAINT covering PRIMARY KEY(a) INCLUDE(b))"
 );
+$node_publisher->safe_psql('postgres',
+	"CREATE TABLE tab_full_pk (a int primary key, b text)");
+$node_publisher->safe_psql('postgres',
+	"ALTER TABLE tab_full_pk REPLICA IDENTITY FULL");
 # Let this table with REPLICA IDENTITY NOTHING, allowing only INSERT changes.
 $node_publisher->safe_psql('postgres', "CREATE TABLE tab_nothing (a int)");
 $node_publisher->safe_psql('postgres',
@@ -46,6 +50,10 @@
 $node_subscriber->safe_psql('postgres', "CREATE TABLE tab_full2 (x text)");
 $node_subscriber->safe_psql('postgres',
 	"CREATE TABLE tab_rep (a int primary key)");
+$node_subscriber->safe_psql('postgres',
+	"CREATE TABLE tab_full_pk (a int primary key, b text)");
+$node_subscriber->safe_psql('postgres',
+	"ALTER TABLE tab_full_pk REPLICA IDENTITY FULL");
 $node_subscriber->safe_psql('postgres', "CREATE TABLE tab_nothing (a int)");
 
 # different column count and order than on publisher
@@ -64,7 +72,7 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE PUBLICATION tap_pub_ins_only WITH (publish = insert)");
 $node_publisher->safe_psql('postgres',
-	"ALTER PUBLICATION tap_pub ADD TABLE tab_rep, tab_full, tab_full2, tab_mixed, tab_include, tab_nothing"
+	"ALTER PUBLICATION tap_pub ADD TABLE tab_rep, tab_full, tab_full2, tab_mixed, tab_include, tab_nothing, tab_full_pk"
 );
 $node_publisher->safe_psql('postgres',
 	"ALTER PUBLICATION tap_pub_ins_only ADD TABLE tab_ins");
@@ -102,6 +110,9 @@
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_mixed VALUES (2, 'bar', 2.2)");
 
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_full_pk VALUES (1, 'foo')");
+
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_nothing VALUES (generate_series(1,20))");
 
@@ -159,6 +170,8 @@
 	"UPDATE tab_full2 SET x = 'bb' WHERE x = 'b'");
 $node_publisher->safe_psql('postgres',
 	"UPDATE tab_mixed SET b = 'baz' WHERE a = 1");
+$node_publisher->safe_psql('postgres',
+	"UPDATE tab_full_pk SET b = 'bar' WHERE a = 1");
 
 $node_publisher->wait_for_catchup('tap_sub');