Horton

Re: make MaxBackends available in _PG_init

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Julien Rouhaud <rjuju123@gmail.com>, Andres Freund <andres@anarazel.de>, "Bossart, Nathan" <bossartn@amazon.com>, Fujii Masao <masao.fujii@oss.nttdata.com>, "wangsh.fnst@fujitsu.com" <wangsh.fnst@fujitsu.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Greg Sabino Mullane <htamfids@gmail.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2022-05-11T04:12:11Z
Lists: pgsql-hackers

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On Wed, May 11, 2022 at 11:18:29AM +0900, Michael Paquier wrote:
> 0002 looks pretty good from here.  If it were me, I would apply 0002
> first to avoid the extra tweak in pg_stat_statements with _PG_fini in
> 0001.

I swapped 0001 and 0002 in v8.

> Regarding 0001, I have spotted an extra issue in the documentation.
> xfunc.sgml has a section called "Shared Memory and LWLocks" about the
> use of RequestNamedLWLockTranche() and RequestAddinShmemSpace() called
> from _PG_init(), which would now be wrong as we'd need the hook.  IMO,
> the docs should mention the registration of the hook in _PG_init(),
> the APIs involved, and should mention to look at pg_stat_statements.c
> for a code sample (we tend to avoid the addition of sample code in the
> docs lately as we habe no way to check their compilation
> automatically).

Ah, good catch.  I adjusted the docs as you suggested.

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

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