From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
cc: Fujii Masao <masao.fujii@gmail.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Release postmaster working memory context in slotsync worker
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Comments: In-reply-to Andres Freund <andres@anarazel.de>
	message dated "Fri, 27 Feb 2026 12:32:24 -0500"
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Date: Fri, 27 Feb 2026 12:58:47 -0500
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Andres Freund <andres@anarazel.de> writes:
> On 2026-02-28 01:25:12 +0900, Fujii Masao wrote:
>> Child processes do not need the postmaster's working memory context and
>> release it at the start of their main function. However, the slotsync w=
orker
>> appears to have missed this step.

> Obviously this inconsistency is not good.  However:
> I think we should consider *not* releasing postmaster memory. Freeing th=
e
> memory actually can lead to an *increase* in memory usage and a slight
> *decrease* in connection startup performance. The reason for that is tha=
t with
> fork, memory allocated in postmaster is handled by copy-on-write in the
> children.

Meh.  I think that's optimizing for the wrong thing.  To my mind the
point of releasing that context is to be sure that child processes
don't have access to postmaster-private data.  Admittedly, we're not
doing anything as drastic as zeroing out the memory, but it'll soon
be overwritten as the child starts up and populates its caches.

			regards, tom lane