From db391b7bb4c4bb0d66bbf65a65086b312882c4f2 Mon Sep 17 00:00:00 2001 From: Nazir Bilal Yavuz Date: Tue, 15 Sep 2026 16:28:28 +0300 Subject: [PATCH v1 1/2] Avoid idle WAL waits in the checksum rewind test Wait for standby replay through the upstream flush LSN rather than its insert position, which can include WAL not yet available for streaming on an idle primary. Backup completion and the explicit checkpoint have already flushed the WAL required by the first two catch-up waits. After rewind, explicitly switch WAL on the source before starting the target. This flushes the WAL needed to reach its minimum recovery point, avoiding a wait for the background writer to log its next snapshot and flush the full_page_writes change. Use the source flush LSN for the final replay wait as well. --- src/test/modules/test_checksums/t/013_rewind.pl | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/test/modules/test_checksums/t/013_rewind.pl b/src/test/modules/test_checksums/t/013_rewind.pl index a791e24317d..9c2dff78f2c 100644 --- a/src/test/modules/test_checksums/t/013_rewind.pl +++ b/src/test/modules/test_checksums/t/013_rewind.pl @@ -71,7 +71,8 @@ my $node_b = PostgreSQL::Test::Cluster->new('node_b'); $node_b->init_from_backup($node_a, 'backup', has_streaming => 1); $node_b->start; -$node_a->wait_for_catchup($node_b, 'replay', $node_a->lsn('insert')); +# Backup completion has flushed the required WAL. +$node_a->wait_for_catchup($node_b, 'replay', $node_a->lsn('flush')); test_checksum_state($node_a, 'off'); test_checksum_state($node_b, 'off'); @@ -83,7 +84,7 @@ $node_b->safe_psql('postgres', # in a background session; it will block on the injection point with # the checkpointer busy until released. $node_a->safe_psql('postgres', "CHECKPOINT;"); -$node_a->wait_for_catchup($node_b, 'replay', $node_a->lsn('insert')); +$node_a->wait_for_catchup($node_b, 'replay', $node_a->lsn('flush')); my $bg_psql = $node_b->background_psql('postgres', on_error_stop => 0); $bg_psql->query_until( @@ -182,9 +183,14 @@ port = @{[$node_a->port]} primary_conninfo = '$connstr application_name=@{[$node_a->name]}' ]); $node_a->set_standby_mode; + +# Flush WAL through the minimum recovery point chosen by pg_rewind. The +# full_page_writes change can leave an unflushed record on the idle source, +# delaying startup until the background writer logs its next snapshot. +$node_b->safe_psql('postgres', 'SELECT pg_switch_wal();'); $node_a->start; -$node_b->wait_for_catchup($node_a, 'replay', $node_b->lsn('insert')); +$node_b->wait_for_catchup($node_a, 'replay', $node_b->lsn('flush')); test_checksum_state($node_a, 'on'); is($node_a->safe_psql('postgres', "SELECT count(*) FROM t;"), -- 2.47.3