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Message-ID: <18181295-8375-4789-ad32-269d78d6001e@gmail.com>
Date: Sun, 12 Apr 2026 17:00:00 +0300
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User-Agent: Mozilla Thunderbird
Subject: Re: Adding REPACK [concurrently]
To: Antonin Houska <ah@cybertec.at>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Amit Kapila <amit.kapila16@gmail.com>,
 "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>,
 Srinath Reddy Sadipiralla <srinath2133@gmail.com>,
 Mihail Nikalayeu <mihailnikalayeu@gmail.com>,
 Matthias van de Meent <boekewurm+postgres@gmail.com>,
 Pg Hackers <pgsql-hackers@lists.postgresql.org>,
 Robert Treat <rob@xzilla.net>
References: <202604072027.gazfa2zt2l2j@alvherre.pgsql>
 <a38fc771-c860-4605-8c44-d16e8aff2534@gmail.com>
 <121156.1775818667@localhost>
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From: Alexander Lakhin <exclusion@gmail.com>
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Hello Antonin and Alvaro,

10.04.2026 13:57, Antonin Houska wrote:
> Attached is a fix that works for me.
>
> Nevertheless, REPACK (CONCURRENTLY) in your test goes ahead only due to commit
> 0d3dba38c7, which will probably be reverted [1]. Then REPACK will wait for the
> transaction in the other database (db1) to complete before it can actually
> start.

Thank you for the fix!

I've stumbled upon one more issue with this feature:
CREATE TABLE t (i int PRIMARY KEY);
REPACK (CONCURRENTLY) t;

fails for me with sanitizers enabled and
min_dynamic_shared_memory = '1GB'
in postgresql.conf as below:
2026-04-12 13:23:02.000 UTC [2733633] LOG:  statement: REPACK (CONCURRENTLY) t;
repack.c:3373:15: runtime error: load of value 240, which is not a valid value for type '_Bool'
     #0 0x6441f7eba454 in start_repack_decoding_worker .../src/backend/commands/repack.c:3373
     #1 0x6441f7ebdaad in rebuild_relation .../src/backend/commands/repack.c:1010
     #2 0x6441f7ebe9a2 in cluster_rel .../src/backend/commands/repack.c:656
     #3 0x6441f7ebefea in process_single_relation .../src/backend/commands/repack.c:2359
     #4 0x6441f7ebf870 in ExecRepack .../src/backend/commands/repack.c:296
     #5 0x6441f886f20e in standard_ProcessUtility .../src/backend/tcop/utility.c:867
...

2026-04-12 13:23:03.620 UTC [2733620] LOG:  client backend (PID 2733633) was terminated by signal 6: Aborted
2026-04-12 13:23:03.620 UTC [2733620] DETAIL:  Failed process was running: REPACK (CONCURRENTLY) t;

Could you please have a look?

Best regards,
Alexander
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    <div class="moz-cite-prefix">Hello Antonin and Alvaro,<br>
      <br>
      10.04.2026 13:57, Antonin Houska wrote:<br>
    </div>
    <blockquote type="cite" cite="mid:121156.1775818667@localhost">
      <pre wrap="" class="moz-quote-pre">Attached is a fix that works for me.

Nevertheless, REPACK (CONCURRENTLY) in your test goes ahead only due to commit
0d3dba38c7, which will probably be reverted [1]. Then REPACK will wait for the
transaction in the other database (db1) to complete before it can actually
start.
</pre>
    </blockquote>
    <br>
    Thank you for the fix!<br>
    <br>
    I've stumbled upon one more issue with this feature:<br>
    CREATE TABLE t (i int PRIMARY KEY);<br>
    REPACK (CONCURRENTLY) t;<br>
    <br>
    fails for me with sanitizers enabled and<br>
    min_dynamic_shared_memory = '1GB'<br>
    in postgresql.conf as below:<br>
    2026-04-12 13:23:02.000 UTC [2733633] LOG:  statement: REPACK
    (CONCURRENTLY) t;<br>
    repack.c:3373:15: runtime error: load of value 240, which is not a
    valid value for type '_Bool'<br>
        #0 0x6441f7eba454 in start_repack_decoding_worker
    .../src/backend/commands/repack.c:3373<br>
        #1 0x6441f7ebdaad in rebuild_relation
    .../src/backend/commands/repack.c:1010<br>
        #2 0x6441f7ebe9a2 in cluster_rel
    .../src/backend/commands/repack.c:656<br>
        #3 0x6441f7ebefea in process_single_relation
    .../src/backend/commands/repack.c:2359<br>
        #4 0x6441f7ebf870 in ExecRepack
    .../src/backend/commands/repack.c:296<br>
        #5 0x6441f886f20e in standard_ProcessUtility
    .../src/backend/tcop/utility.c:867<br>
    ...<br>
    <br>
    2026-04-12 13:23:03.620 UTC [2733620] LOG:  client backend (PID
    2733633) was terminated by signal 6: Aborted<br>
    2026-04-12 13:23:03.620 UTC [2733620] DETAIL:  Failed process was
    running: REPACK (CONCURRENTLY) t;<br>
    <br>
    Could you please have a look?<br>
    <br>
    Best regards,<br>
    Alexander<br>
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