Horton

Re: Weird failure with latches in curculio on v15

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Thomas Munro <thomas.munro@gmail.com>, Fujii Masao <fujii@postgresql.org>, Postgres hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-02-05T22:19:38Z
Lists: pgsql-hackers 
On Sun, Feb 05, 2023 at 09:49:57AM +0900, Michael Paquier wrote:
> - Should we include archive_cleanup_command into the recovery modules
> at all?  We've discussed offloading that from the checkpointer, and it
> makes the failure handling trickier when it comes to unexpected GUC
> configurations, for one.  The same may actually apply to
> restore_end_command.  Though it is done in the startup process now,
> there may be an argument to offload that somewhere else based on the
> timing of the end-of-recovery checkpoint.  My opinion on this stuff is
> that only including restore_command in the modules would make most
> users I know of happy enough as it removes the overhead of the command
> invocation from the startup process, if able to replay things fast
> enough so as the restore command is the bottleneck.
> restore_end_command would be simple enough, but if there is a wish to
> redesign the startup process to offload it somewhere else, then the
> recovery module makes backward-compatibility concerns harder to think
> about in the long-term.

I agree.  I think we ought to first focus on getting the recovery modules
interface and restore_command functionality in place before we take on more
difficult things like archive_cleanup_command.  But I still think the
archive_cleanup_command/recovery_end_command functionality should
eventually be added to recovery modules.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Commits

  1. Avoid calling proc_exit() in processes forked by system().

  2. Move extra code out of the Pre/PostRestoreCommand() section.

  3. Revert refactoring of restore command code to shell_restore.c

  4. Refactor code in charge of running shell-based recovery commands

  5. Clean up inconsistent use of fflush().

  6. Report wait events for local shell commands like archive_command.