commit e3d9337aa01539ce77553d95db47aa919d1f501c
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Date:   Mon Apr 7 06:56:08 2025 +0000

    logical walsender test

diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl
index 8726fe04ad2..2253ee48312 100644
--- a/src/test/subscription/t/001_rep_changes.pl
+++ b/src/test/subscription/t/001_rep_changes.pl
@@ -113,6 +113,9 @@ $node_subscriber->safe_psql('postgres',
 # Wait for initial table sync to finish
 $node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
 
+# To check that an active walsender updates its IO statistics below.
+$node_publisher->safe_psql('postgres', "SELECT pg_stat_reset_shared('io')");
+
 my $result =
   $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM tab_notrep");
 is($result, qq(0), 'check non-replicated table is empty on subscriber');
@@ -184,6 +187,19 @@ $result =
   $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM tab_no_col");
 is($result, qq(2), 'check replicated changes for table having no columns');
 
+# Wait for the walsender to update its IO statistics.
+# Has to be done before the next restart and far enough from the
+# pg_stat_reset_shared('io') to minimize the risk of polling for too long.
+$node_publisher->poll_query_until(
+	'postgres',
+	qq[SELECT sum(reads) > 0
+       FROM pg_catalog.pg_stat_io
+       WHERE backend_type = 'walsender'
+       AND object = 'wal']
+  )
+  or die
+  "Timed out while waiting for the walsender to update its IO statistics";
+
 # insert some duplicate rows
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_full SELECT generate_series(1,10)");