Re: Remove toast_max_chunk_size from control file

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Michael Paquier <michael(at)paquier(dot)xyz>
Cc: Postgres hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Remove toast_max_chunk_size from control file
Date: 2026-09-07 01:43:33
Message-ID: 150388.1788745413@sss.pgh.pa.us
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Michael Paquier <michael(at)paquier(dot)xyz> writes:
> Requoting my previous message that you did not include:

>> There may be an argument about somebody enforcing a new
>> TOAST_OID_MAX_CHUNK_SIZE or EXTERN_TUPLES_PER_PAGE manually, of
>> course, but while we claim that tweaks are possible in heaptoast.h,

> I've never seen anybody actually do that. So yes, I agree that if
> somebody has the idea to change this value manually, the control file
> value makes sense to keep. It's just that I doubt that anybody is
> actually doing that. :)

Perhaps not, but the point of these disk-layout-compatibility fields
in pg_control is to keep people from shooting themselves in the foot.
I don't think it's that unlikely that someone would decide that four
TOAST tuples per page isn't ideal, especially if they were running
with non-default BLCKSZ.

regards, tom lane

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