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>
Subject: Re: make MaxBackends available in _PG_init
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Comments: In-reply-to Greg Sabino Mullane <htamfids@gmail.com>
	message dated "Wed, 11 Aug 2021 09:41:43 -0400"
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Date: Wed, 11 Aug 2021 10:08:01 -0400
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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