Add test coverage for "unchanged toast column" replication code path.

It seems pretty unacceptable to have no regression test coverage
for this aspect of the logical replication protocol, especially
given the bugs we've found in related code.

Discussion: https://postgr.es/m/16129-a0c0f48e71741e5f@postgresql.org

diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl
index f2be0e21ea52ec6eeb50f0a0619f932649d0aae6..77a1560b23daa80d5dcfe8d0b915341735159e02 100644 (file)
--- a/src/test/subscription/t/001_rep_changes.pl
+++ b/src/test/subscription/t/001_rep_changes.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 20;
+use Test::More tests => 22;
 
 # Initialize publisher node
 my $node_publisher = get_new_node('publisher');
@@ -168,9 +168,38 @@ is( $result, qq(local|1.1|baz|1
 local|2.2|bar|2),
    'update works with different column order and subscriber local values');
 
+# check behavior with toasted values
+
+$node_publisher->safe_psql('postgres',
+   "UPDATE tab_mixed SET b = repeat('xyzzy', 100000) WHERE a = 2");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+$result = $node_subscriber->safe_psql('postgres',
+   "SELECT a, length(b), c, d FROM tab_mixed ORDER BY a");
+is( $result, qq(1|3|1.1|local
+2|500000|2.2|local),
+   'update transmits large column value');
+
+$node_publisher->safe_psql('postgres',
+   "UPDATE tab_mixed SET c = 3.3 WHERE a = 2");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+$result = $node_subscriber->safe_psql('postgres',
+   "SELECT a, length(b), c, d FROM tab_mixed ORDER BY a");
+is( $result, qq(1|3|1.1|local
+2|500000|3.3|local),
+   'update with non-transmitted large column value');
+
 # check behavior with dropped columns
 
+# this update should get transmitted before the column goes away
+$node_publisher->safe_psql('postgres',
+   "UPDATE tab_mixed SET b = 'bar', c = 2.2 WHERE a = 2");
+
 $node_publisher->safe_psql('postgres', "ALTER TABLE tab_mixed DROP COLUMN b");
+
 $node_publisher->safe_psql('postgres',
    "UPDATE tab_mixed SET c = 11.11 WHERE a = 1");