Horton

Re: make MaxBackends available in _PG_init

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: "Bossart, Nathan" <bossartn@amazon.com>, Robert Haas <robertmhaas@gmail.com>, Fujii Masao <masao.fujii@oss.nttdata.com>, "wangsh.fnst@fujitsu.com" <wangsh.fnst@fujitsu.com>, Andres Freund <andres@anarazel.de>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Greg Sabino Mullane <htamfids@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2022-01-28T04:22:25Z
Lists: pgsql-hackers 
On Thu, Jan 27, 2022 at 10:18:15AM -0800, Nathan Bossart wrote:
> On Thu, Jan 27, 2022 at 09:56:04AM +0900, Michael Paquier wrote:
>> Hmm.  I have been looking at this patch, and the lack of centralized
>> solution that could be used for other GUCs worries me like Fujii-san,
>> even if this would prevent an incorrect use of MaxBackends in contexts
>> where it should not be used because it is not initialized yet.  I
>> don't think it is a good idea in the long-term to apply this as-is.
> 
> Alright.  I think the comment adjustments still apply, so I split those out
> to a new patch.

No objections to this part from here, though I have not checked if
there are other areas that may require such an adjustment.
--
Michael

Commits

  1. Add a new shmem_request_hook hook.

  2. Remove non-functional code for unloading loadable modules.

  3. Fix misleading comments about background worker registration.

  4. Revert the addition of GetMaxBackends() and related stuff.

  5. Fix typo in multixact.c

  6. Reduce more the number of calls to GetMaxBackends()

  7. Remove MaxBackends variable in favor of GetMaxBackends() function.

  8. Fix comments about bgworker registration before MaxBackends initialization

  9. Fix bogus assertion in BootstrapModeMain().

  10. Make sure MaxBackends is always set