Re: Add the ability to limit the amount of memory that can be allocated to backends.

From: Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>
To: reid(dot)thompson(at)crunchydata(dot)com
Cc: pgsql-hackers(at)lists(dot)postgresql(dot)org
Subject: Re: Add the ability to limit the amount of memory that can be allocated to backends.
Date: 2022-09-01 02:48:40
Message-ID: 20220901.114840.1629861209007649117.horikyota.ntt@gmail.com
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At Wed, 31 Aug 2022 12:50:19 -0400, Reid Thompson <reid(dot)thompson(at)crunchydata(dot)com> wrote in
> Hi Hackers,
>
> Add the ability to limit the amount of memory that can be allocated to
> backends.

The patch seems to limit both of memory-context allocations and DSM
allocations happen on a specific process by the same budget. In the
fist place I don't think it's sensible to cap the amount of DSM
allocations by per-process budget.

DSM is used by pgstats subsystem. There can be cases where pgstat
complains for denial of DSM allocation after the budget has been
exhausted by memory-context allocations, or every command complains
for denial of memory-context allocation after once the per-process
budget is exhausted by DSM allocations. That doesn't seem reasonable.

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center

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