Horton

Re: make MaxBackends available in _PG_init

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Greg Sabino Mullane <htamfids@gmail.com>
Cc: "Bossart, Nathan" <bossartn@amazon.com>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2021-08-11T14:08:01Z
Lists: pgsql-hackers 
Greg Sabino Mullane <htamfids@gmail.com> writes:
> v3 looks good, but I'm still not sure how to test the bit mentioned above.
> I'm not familiar with this part of the code (SubPostmasterMain etc.), but
> running make check-world with EXEC_BACKEND does not seem to execute that
> code, as I added exit(1) to restore_backend_variables() and the tests still
> ran fine.

You must not have enabled EXEC_BACKEND properly.  It's a compile-time
#define that affects multiple modules, so it's easy to get wrong.
The way I usually turn it on is

	make distclean
	./configure ... options of choice ...
	edit src/include/pg_config.h, add "#define EXEC_BACKEND" line
	make, install, test

In this way the setting is persistent till the next distclean/configure
cycle.

			regards, tom lane

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