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Message-ID: <2b09fba6-6b71-497a-96ef-a6947fcc39f6@gmail.com>
Date: Thu, 29 Jan 2026 07:00:00 +0200
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
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: Andrey Borodin <x4mmm@yandex-team.ru>,
 Kirill Reshke <reshkekirill@gmail.com>, Chao Li <li.evan.chao@gmail.com>,
 Xuneng Zhou <xunengzhou@gmail.com>, Robert Haas <robertmhaas@gmail.com>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Heikki Linnakangas <hlinnaka@iki.fi>
References: <CABPTF7X1X810eT7hjRz9M69sjMv1Vui5gXQEGhqYXmkmywhHCQ@mail.gmail.com>
 <CAAKRu_ZcK+ez71W7j+QzMo0gSafTsbGA3TU-fVSptw7yh41BEQ@mail.gmail.com>
 <6BC5DBAB-6084-4BB8-8450-52E9648AB021@gmail.com>
 <CAAKRu_ZCjHoRPfQ8AbMrFY8TOMCPAvZ0_m9SX7yg0edfTk45-g@mail.gmail.com>
 <7F5BCD7A-764D-4D8D-8E27-6F2CAAEA1CEE@gmail.com>
 <CAAKRu_a04jbDACwzRYwzDND31aPyf7Yvz9TAZrTr=+F5bK1aVA@mail.gmail.com>
 <CALdSSPjcv25jmXm29X-MRWZBae6+HwcWfVH1PE8NfD=EMTnkAg@mail.gmail.com>
 <CAAKRu_bwtBEzDwemyim1r6yYonw7FTyFr1HXG8vywCe-MdbPBQ@mail.gmail.com>
 <4379FDA3-9446-4E2C-9C15-32EFE8D4F31B@yandex-team.ru>
 <CAAKRu_YQd=2KvomM+RHcpeDKj0bq+peJ=3W-fip+pkvzA-Jq9w@mail.gmail.com>
 <7ib3sa55sapwjlaz4sijbiq7iezna27kjvvvar4dpgkmadml6t@gfpkkwmdnepx>
 <CAAKRu_bs+gZ83QDacmBxunPvCGnXJ05hxP2BDPJ3BGwdbGRXzg@mail.gmail.com>
Content-Language: en-US
From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <CAAKRu_bs+gZ83QDacmBxunPvCGnXJ05hxP2BDPJ3BGwdbGRXzg@mail.gmail.com>
Archived-At: <https://www.postgresql.org/message-id/2b09fba6-6b71-497a-96ef-a6947fcc39f6%40gmail.com>
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Hello Melanie,

29.01.2026 01:16, Melanie Plageman wrote:
> Thanks for the review!
> I pushed v33 0001-0003 after incorporating your feedback.

The buildfarm animal scorpion has detected an instability of the addition
to pg_visibility from 21796c267 [1]:

80/82 postgresql:pg_visibility-running / pg_visibility-running/regress             ERROR             7.23s exit status 1

diff -U3 /home/bf/bf-build/scorpion/HEAD/pgsql/contrib/pg_visibility/expected/pg_visibility.out 
/home/bf/bf-build/scorpion/HEAD/pgsql.build/testrun/pg_visibility-running/regress/results/pg_visibility.out
--- /home/bf/bf-build/scorpion/HEAD/pgsql/contrib/pg_visibility/expected/pg_visibility.out 2026-01-26 22:07:12.923378464 
+0100
+++ /home/bf/bf-build/scorpion/HEAD/pgsql.build/testrun/pg_visibility-running/regress/results/pg_visibility.out 
2026-01-28 20:15:13.802517085 +0100
@@ -213,7 +213,7 @@
  select pg_visibility_map_summary('test_vac_unmodified_heap');
   pg_visibility_map_summary
  ---------------------------
- (1,1)
+ (0,0)
  (1 row)

  -- the checkpoint cleans the buffer dirtied by freezing the sole tuple
@@ -237,7 +237,7 @@
          FROM page_header(get_raw_page('test_vac_unmodified_heap', 0));
   ?column?
  ----------
- t
+ f
  (1 row)

  -- vacuum sets the VM

I've managed to reproduce it locally with the attached and:
echo "autovacuum_naptime = 1" > /tmp/temp.config
TEMP_CONFIG=/tmp/temp.config make -s check -C contrib/pg_visibility/
...
ok 85        - pg_visibility                              30 ms
not ok 86    - pg_visibility                             165 ms
ok 87        - pg_visibility                              36 ms
...
# 1 of 100 tests failed.

Could you please look at this?

Probably you'll find [2] helpful.

[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=scorpion&dt=2026-01-28%2019%3A07%3A32
[2] https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=1c64d2fcb

Best regards,
Alexander
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<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  </head>
  <body>
    <div class="moz-cite-prefix">Hello Melanie,<br>
      <br>
      29.01.2026 01:16, Melanie Plageman wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAAKRu_bs+gZ83QDacmBxunPvCGnXJ05hxP2BDPJ3BGwdbGRXzg@mail.gmail.com">
      <pre wrap="" class="moz-quote-pre">Thanks for the review!
I pushed v33 0001-0003 after incorporating your feedback.
</pre>
    </blockquote>
    <br>
    The buildfarm animal scorpion has detected an instability of the
    addition<br>
    to pg_visibility from 21796c267 [1]:<br>
    <br>
    80/82 postgresql:pg_visibility-running /
    pg_visibility-running/regress             ERROR             7.23s  
    exit status 1<br>
    <br>
    diff -U3
/home/bf/bf-build/scorpion/HEAD/pgsql/contrib/pg_visibility/expected/pg_visibility.out
/home/bf/bf-build/scorpion/HEAD/pgsql.build/testrun/pg_visibility-running/regress/results/pg_visibility.out<br>
    ---
/home/bf/bf-build/scorpion/HEAD/pgsql/contrib/pg_visibility/expected/pg_visibility.out   
    2026-01-26 22:07:12.923378464 +0100<br>
    +++
/home/bf/bf-build/scorpion/HEAD/pgsql.build/testrun/pg_visibility-running/regress/results/pg_visibility.out   
    2026-01-28 20:15:13.802517085 +0100<br>
    @@ -213,7 +213,7 @@<br>
     select pg_visibility_map_summary('test_vac_unmodified_heap');<br>
      pg_visibility_map_summary <br>
     ---------------------------<br>
    - (1,1)<br>
    + (0,0)<br>
     (1 row)<br>
     <br>
     -- the checkpoint cleans the buffer dirtied by freezing the sole
    tuple<br>
    @@ -237,7 +237,7 @@<br>
             FROM page_header(get_raw_page('test_vac_unmodified_heap',
    0));<br>
      ?column? <br>
     ----------<br>
    - t<br>
    + f<br>
     (1 row)<br>
     <br>
     -- vacuum sets the VM<br>
    <br>
    I've managed to reproduce it locally with the attached and:<br>
    echo "autovacuum_naptime = 1" &gt; /tmp/temp.config<br>
    TEMP_CONFIG=/tmp/temp.config make -s check -C contrib/pg_visibility/<br>
    ...<br>
    ok 85        - pg_visibility                              30 ms<br>
    not ok 86    - pg_visibility                             165 ms<br>
    ok 87        - pg_visibility                              36 ms<br>
    ...<br>
    # 1 of 100 tests failed.<br>
    <br>
    Could you please look at this?<br>
    <br>
    Probably you'll find [2] helpful.<br>
    <br>
    [1]
<a class="moz-txt-link-freetext" href="https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=scorpion&amp;dt=2026-01-28%2019%3A07%3A32">https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=scorpion&amp;dt=2026-01-28%2019%3A07%3A32</a><br>
    [2]
    <a class="moz-txt-link-freetext" href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=1c64d2fcb">https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=1c64d2fcb</a><br>
    <br>
    Best regards,<br>
    Alexander<br>
  </body>
</html>

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