Re: fix bgworkers in EXEC_BACKEND

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Stephen Frost <sfrost@snowman.net>
Cc: Simon Riggs <simon@2ndQuadrant.com>, Heikki Linnakangas <hlinnakangas@vmware.com>, Alvaro Herrera <alvherre@2ndQuadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2012-12-27T19:08:11Z
Lists: pgsql-hackers
Stephen Frost <sfrost@snowman.net> writes:
> Simon,
> * Simon Riggs (simon@2ndQuadrant.com) wrote:
>> I admire your forward thinking on that; yes, that could cause
>> problems. But even then, we would be admitting that nobody now gets a
>> valid value of MaxBackends, which sounds like it might be a problem in
>> itself.

> I agree that the current implementation could lead to problems/confusion
> for contrib module authors, if they're doing something with MaxBackends.

This is more or less a necessary consequence of the fact that _init
functions are now allowed to add background workers.  If there is any
code today that expects MaxBackends to be correct at
preload_shared_libraries time, it's already been broken irretrievably
by the bgworkers patch; and we'd be well advised to make that breakage
obvious not subtle.

So I'm +1 for Heikki's proposal as well.

			regards, tom lane