From 8047a7b9dd454a6514ab7d0fcbe27aca3ec2e11c Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 22 Nov 2019 12:52:26 -0500
Subject: [PATCH] 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
---
 src/test/subscription/t/001_rep_changes.pl | 31 +++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl
index f2be0e21ea..77a1560b23 100644
--- 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");