[Karina Litskevich <litskevichkarina@gmail.com>]

Hi Alvaro!

Is there any special reason to read WAL records until the last inserted 
record?

+my $end_lsn = $whiskey->lsn('insert');
+
+my ($ret, $out, $err) = $whiskey->psql(
+    'postgres', qq{
+    select count(*) from pg_get_wal_records_info('$start_lsn', '$end_lsn')
+    where resource_manager = 'BRIN' AND
+    record_type ILIKE '%revmap%'
+    });
+cmp_ok($out, '>=', 1);

It seems that in some rare situations on slower machines this test can 
fail. If
any background process inserts a WAL record before lsn('insert') and 
this record
isn't flushed before pg_get_wal_records_info('$start_lsn', '$end_lsn'),
pg_get_wal_records_info('$start_lsn', '$end_lsn') ends with ERROR 
"cannot accept
future end LSN" as it works only if record with end LSN is inserted.

I attached two patches with two ways of fixing this minor issue.

Best regards,
Karina Litskevich
Postgres Professional: http://postgrespro.com/

Attachments: download all (2 files, .tar.gz)

v1-0001-prevent-test-from-failing-on-slower-machines.patch (text/x-patch, 772B) download
From 75a56e7bd5bc718481099bda3668855f9c200e98 Mon Sep 17 00:00:00 2001
From: Karina Litskevich <litskevichkarina@gmail.com>
Date: Fri, 23 Dec 2022 16:35:23 +0300
Subject: [PATCH v1] prevent test from failing on slower machines

---
 src/test/modules/brin/t/02_wal_consistency.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/modules/brin/t/02_wal_consistency.pl b/src/test/modules/brin/t/02_wal_consistency.pl
index f7dbb0d014..cbc269b1df 100644
--- a/src/test/modules/brin/t/02_wal_consistency.pl
+++ b/src/test/modules/brin/t/02_wal_consistency.pl
@@ -60,7 +60,7 @@ begin
 end
 $$;
 });
-my $end_lsn = $whiskey->lsn('insert');
+my $end_lsn = $whiskey->lsn('flush');
 
 my ($ret, $out, $err) = $whiskey->psql(
 	'postgres', qq{
-- 
2.25.1



v2-0001-prevent-test-from-failing-on-slower-machines.patch (text/x-patch, 962B) download
From e4aff210c95ed548f4c54f9314c4b58580663a74 Mon Sep 17 00:00:00 2001
From: Karina Litskevich <litskevichkarina@gmail.com>
Date: Fri, 23 Dec 2022 16:41:48 +0300
Subject: [PATCH v2] prevent test from failing on slower machines

---
 src/test/modules/brin/t/02_wal_consistency.pl | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/test/modules/brin/t/02_wal_consistency.pl b/src/test/modules/brin/t/02_wal_consistency.pl
index f7dbb0d014..a7aeadf4bb 100644
--- a/src/test/modules/brin/t/02_wal_consistency.pl
+++ b/src/test/modules/brin/t/02_wal_consistency.pl
@@ -60,11 +60,10 @@ begin
 end
 $$;
 });
-my $end_lsn = $whiskey->lsn('insert');
 
 my ($ret, $out, $err) = $whiskey->psql(
 	'postgres', qq{
-	select count(*) from pg_get_wal_records_info('$start_lsn', '$end_lsn')
+	select count(*) from pg_get_wal_records_info_till_end_of_wal('$start_lsn')
 	where resource_manager = 'BRIN' AND
 	record_type ILIKE '%revmap%'
 	});
-- 
2.25.1