Message-ID: <97529f5a-ec10-46b1-ab50-4653126c6889@gmail.com>
Date: Fri, 3 Apr 2026 08:00:00 +0300
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Subject: Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM
 on-access)
To: Melanie Plageman <melanieplageman@gmail.com>,
 Andres Freund <andres@anarazel.de>
Cc: Tomas Vondra <tomas@vondra.me>, David Rowley <dgrowleyml@gmail.com>,
 Kirill Reshke <reshkekirill@gmail.com>, Chao Li <li.evan.chao@gmail.com>,
 Andrey Borodin <x4mmm@yandex-team.ru>, Xuneng Zhou <xunengzhou@gmail.com>,
 Robert Haas <robertmhaas@gmail.com>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Heikki Linnakangas <hlinnaka@iki.fi>
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From: Alexander Lakhin <exclusion@gmail.com>
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Hello Melanie and Andres,

31.03.2026 19:19, Melanie Plageman wrote:
> Thanks for the reply! I have committed the patches in this thread and
> marked the CF entry accordingly.

I've come across an interesting failure produced starting from 378a21618:
when using a build made with CFLAGS="-DRELCACHE_FORCE_RELEASE" and
echo "io_method = sync" >/tmp/temp.config, the test run:
TEMP_CONFIG=/tmp/temp.config TESTS=temp make -s check-tests

fails as below:
--- .../src/test/regress/expected/temp.out   2026-02-13 06:15:55.887368624 +0200
+++ .../src/test/regress/results/temp.out    2026-04-03 07:51:36.735504156 +0300
@@ -493,11 +493,7 @@

  -- Check that read streams deal with lower number of pins available
  SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp;
- count | max_a | min_a | max_cnt
--------+-------+-------+---------
- 10000 | 10000 |     1 |       0
-(1 row)
-
+ERROR:  no empty local buffer available
  ROLLBACK;

Could you look please, if it indicates some regression?

Best regards,
Alexander