On Wed, Sep 14, 2022 at 06:12:09PM -0400, Tom Lane wrote:
> Nathan Bossart <nathandbossart@gmail.com> writes:
>> On Wed, Sep 14, 2022 at 04:47:23PM -0400, Tom Lane wrote:
>>> Yeah, the objection there is only to trying to enforce such
>>> interrelationships in GUC hooks. In this case it seems to me that
>>> we could easily check and complain at the point where we're about
>>> to use the GUC values.
>
>> I think the cleanest way to do something like that would be to load a
>> check_configured_cb that produces a WARNING. IIRC failing in
>> LoadArchiveLibrary() would just cause the archiver process to restart over
>> and over. HandlePgArchInterrupts() might need some work as well.
>
> Hm. Maybe consistency-check these settings in the postmaster, sometime
> after we've absorbed all GUC settings but before we launch any children?
> That could provide a saner implementation for the recovery_target_*
> variables too.
Both archive_command and archive_library are PGC_SIGHUP, so IIUC that
wouldn't be sufficient. I attached a quick sketch that seems to provide
the desired behavior. It's nowhere near committable yet, but it
demonstrates what I'm thinking.
For recovery_target_*, something like you are describing seems reasonable.
I believe PostmasterMain() already performs some similar checks.
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
