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Message-ID: <19788b24-cf4c-44fb-b6a7-5a73293cf83e@gmail.com>
Date: Mon, 6 Jul 2026 21:00:01 +0300
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Subject: Re: BUG #19519: REPACK can fail due to missing chunk for toast value
To: Michael Paquier <michael@paquier.xyz>
Cc: Imran Zaheer <imran.zhir@gmail.com>,
 Srinath Reddy Sadipiralla <srinath2133@gmail.com>,
 pgsql-bugs@lists.postgresql.org
References: <19519-fe02d8ff679d834d@postgresql.org>
 <CAFC+b6rLNvDzzYxrfLdq7CWbbouHcuOxi-mjEOW1r3qy2uAPMQ@mail.gmail.com>
 <CA+UBfan1QukfNDPvb2YpPG-ME4vUduBfbbe5uWptXDryZbtwVA@mail.gmail.com>
 <aktM919ANQGYZcsj@paquier.xyz>
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From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <aktM919ANQGYZcsj@paquier.xyz>
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Hello Michael,

06.07.2026 09:36, Michael Paquier wrote:
> Thoughts and comments from others are welcome for now.  My day is
> almost out, at least I got all these scenarios working some tests.

Unfortunately, I still can produce that error running my repro script,
with higher concurrency:
for ((c=1;c<=50;c++)); do createdb db$c; done

for ((i=1;i<=100;i++)); do
echo "iteration $i"
   for ((c=1;c<=50;c++)); do
echo "\\d sometable" | psql -d db$c >psql-1-$c.log 2>&1 &
echo "DROP TABLE IF EXISTS tbl;
CREATE TABLE tbl (i int, t text);
ALTER TABLE tbl ALTER COLUMN t SET STORAGE EXTERNAL;
INSERT INTO tbl(i, t) VALUES (1, repeat('1234567890', 250));
DELETE FROM tbl;

VACUUM (TRUNCATE, VERBOSE) tbl;
VACUUM FULL tbl;
" | psql -d db$c >psql-$c.log 2>&1 &
   done
wait
grep 'missing chunk number' server.log  && break;
done

...
iteration 45
iteration 46
iteration 47
2026-07-06 17:38:19.952 UTC|law|db22|6a4be80b.3ab9a8|ERROR:  missing chunk number 0 for toast value 41866 in pg_toast_41849

I had failures on iterations 47, 58, 79.

(Konstantin's patch doesn't help either.)

Best regards,
Alexander
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    <div class="moz-cite-prefix">Hello Michael,<br>
      <br>
      06.07.2026 09:36, Michael Paquier wrote:<span
      style="white-space: pre-wrap">
</span></div>
    <blockquote type="cite" cite="mid:aktM919ANQGYZcsj@paquier.xyz">
      <pre wrap="" class="moz-quote-pre">Thoughts and comments from others are welcome for now.  My day is
almost out, at least I got all these scenarios working some tests.
</pre>
    </blockquote>
    <br>
    Unfortunately, I still can produce that error running my repro
    script,<br>
    with higher concurrency:<br>
    for ((c=1;c&lt;=50;c++)); do createdb db$c; done<br>
    <br>
    for ((i=1;i&lt;=100;i++)); do<br>
    echo "iteration $i"<br>
      for ((c=1;c&lt;=50;c++)); do<br>
    echo "\\d sometable" | psql -d db$c &gt;psql-1-$c.log 2&gt;&amp;1
    &amp;<br>
    echo "DROP TABLE IF EXISTS tbl;<br>
    CREATE TABLE tbl (i int, t text);<br>
    ALTER TABLE tbl ALTER COLUMN t SET STORAGE EXTERNAL;<br>
    INSERT INTO tbl(i, t) VALUES (1, repeat('1234567890', 250));<br>
    DELETE FROM tbl;<br>
    <br>
    VACUUM (TRUNCATE, VERBOSE) tbl;<br>
    VACUUM FULL tbl;<br>
    " | psql -d db$c &gt;psql-$c.log 2&gt;&amp;1 &amp;<br>
      done<br>
    wait<br>
    grep 'missing chunk number' server.log  &amp;&amp; break;<br>
    done<br>
    <br>
    ...<br>
    iteration 45<br>
    iteration 46<br>
    iteration 47<br>
    2026-07-06 17:38:19.952 UTC|law|db22|6a4be80b.3ab9a8|ERROR:  missing
    chunk number 0 for toast value 41866 in pg_toast_41849<br>
    <br>
    I had failures on iterations 47, 58, 79.<br>
    <br>
    (Konstantin's patch doesn't help either.)<br>
    <br>
    Best regards,<br>
    Alexander<br>
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