Hi,
On Fri, Dec 20, 2024 at 08:00:00AM +0200, Alexander Lakhin wrote:
> Hello Michael,
>
> 19.12.2024 06:21, Michael Paquier wrote:
> > Fixed that, bumped the two version counters, and done.
>
> Could you, please, look at recent failures produced by grassquit (which
> has fsync = on in it's config), on an added test case? For instance, [1]:
> ---
> /home/bf/bf-build/grassquit/HEAD/pgsql/src/test/regress/expected/stats.out
> 2024-12-19 04:44:08.779311933 +0000
> +++
> /home/bf/bf-build/grassquit/HEAD/pgsql.build/testrun/recovery/027_stream_regress/data/results/stats.out
> 2024-12-19 16:37:41.351784840 +0000
> @@ -1333,7 +1333,7 @@
> AND :my_io_sum_shared_after_fsyncs= 0);
> ?column?
> ----------
> - t
> + f
> (1 row)
>
> The complete query is:
> SELECT current_setting('fsync') = 'off'
> OR (:my_io_sum_shared_after_fsyncs = :my_io_sum_shared_before_fsyncs
> AND :my_io_sum_shared_after_fsyncs= 0);
>
> And the corresponding query in 027_stream_regress_primary.log is:
> 2024-12-19 16:37:39.907 UTC [4027467][client backend][15/1980:0] LOG:
> statement: SELECT current_setting('fsync') = 'off'
> OR (1 = 1
> AND 1= 0);
>
> (I can reproduce this locally with an asan-enabled build too.)
>
> [1]
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=grassquit&dt=2024-12-19%2016%3A28%3A58
Thanks for the report! I was not able able to reproduce (even with asan-enabled)
but I think the test is wrong. Indeed the backend could fsync too during the
test
(see register_dirty_segment() and the case where the request queue is full).
I think the test should look like the attached instead, thoughts?
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
>From a83def4ca95c154e824378452cb15f100887a56c Mon Sep 17 00:00:00 2001
From: Bertrand Drouvot <bertranddrouvot...@gmail.com>
Date: Fri, 20 Dec 2024 08:59:53 +0000
Subject: [PATCH v1] Fix per-backend IO stats regression test
The tests added in 9aea73fc61 did not take into account that the backend can
fsync in some circumstances.
---
src/test/regress/expected/stats.out | 3 +--
src/test/regress/sql/stats.sql | 3 +--
2 files changed, 2 insertions(+), 4 deletions(-)
50.0% src/test/regress/expected/
50.0% src/test/regress/sql/
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 150b6dcf74..d18fc7c081 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -1329,8 +1329,7 @@ SELECT :my_io_sum_shared_after_writes >= :my_io_sum_shared_before_writes;
(1 row)
SELECT current_setting('fsync') = 'off'
- OR (:my_io_sum_shared_after_fsyncs = :my_io_sum_shared_before_fsyncs
- AND :my_io_sum_shared_after_fsyncs= 0);
+ OR :my_io_sum_shared_after_fsyncs >= :my_io_sum_shared_before_fsyncs;
?column?
----------
t
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 1e7d0ff665..fc0d2fde31 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -648,8 +648,7 @@ SELECT sum(writes) AS writes, sum(fsyncs) AS fsyncs
WHERE object = 'relation' \gset my_io_sum_shared_after_
SELECT :my_io_sum_shared_after_writes >= :my_io_sum_shared_before_writes;
SELECT current_setting('fsync') = 'off'
- OR (:my_io_sum_shared_after_fsyncs = :my_io_sum_shared_before_fsyncs
- AND :my_io_sum_shared_after_fsyncs= 0);
+ OR :my_io_sum_shared_after_fsyncs >= :my_io_sum_shared_before_fsyncs;
-- Change the tablespace so that the table is rewritten directly, then SELECT
-- from it to cause it to be read back into shared buffers.
--
2.34.1
