Horton

Re: Adding REPACK [concurrently]

Antonin Houska <ah@cybertec.at>

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From: Antonin Houska <ah@cybertec.at>
To: pgsql-hackers@lists.postgresql.org
Cc: alvherre@kurilemu.de, Robert Treat <rob@xzilla.net>, Fujii Masao <masao.fujii@gmail.com>, Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Date: 2025-08-20T08:53:13Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Improve REPACK (CONCURRENTLY) error messages some more

  2. Add CONCURRENTLY option to REPACK

  3. Make index_concurrently_create_copy more general

  4. Document the 'command' column of pg_stat_progress_repack

  5. Introduce the REPACK command

  6. Split vacuumdb to create vacuuming.c/h

  7. Revert changes to CONCURRENTLY that "sped up" Xmin advance

Álvaro Herrera <alvherre@kurilemu.de> wrote:

> Still on pg_repackdb, the implementation here is to install a symlink
> called pg_repackdb which points to vacuumdb, and make the program behave
> differently when called in this way.  The amount of additional code for
> this is relatively small, so I think this is a worthy technique --
> assuming it works.  If it doesn't, Antonin proposed a separate binary
> that just calls some functions from vacuumdb.  Or maybe we could have a
> common source file that both utilities call.

There's an issue with the symlink, maybe some meson expert can help. In
particular, the CI on Windows ends up with the following error:

ERROR: Tried to install symlink to missing file C:/cirrus/build/tmp_install/usr/local/pgsql/bin/vacuumdb

(The reason it does not happen on other platforms might be that the build is
slower on Windows, and thus it's more prone to some specific race conditions.)

It appears that the 'point_to' argument of the 'install_symlink()' function
[1] is only a string rather than a "real target" [2]. That's likely the reason
the function does not wait for the creation of the 'vacuumdb' executable.

I could not find another symlink of this kind in the tree. (AFAICS, the
postmaster->postgres symlink had been removed before Meson has been
introduced.)

Does anyone happen to have a clue? Thanks.

[1] https://mesonbuild.com/Reference-manual_functions.html#install_symlink
[2] https://mesonbuild.com/Reference-manual_returned_tgt.html

-- 
Antonin Houska
Web: https://www.cybertec-postgresql.com