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From: Thomas Munro <thomas.munro@gmail.com>
Date: Wed, 20 Nov 2024 12:37:24 +1300
Message-ID: <CA+hUKGKKUoS4PDjjP_j6tHRS7jPm=Pu+4Ai56ZT+UWoT2FRcoQ@mail.gmail.com>
Subject: Re: Running docker in postgres, SHM size of the docker container in
 postgres 16
To: Koen De Groote <kdg.dev@gmail.com>
Cc: PostgreSQL General <pgsql-general@lists.postgresql.org>
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On Wed, Nov 20, 2024 at 11:22=E2=80=AFAM Koen De Groote <kdg.dev@gmail.com>=
 wrote:
> Why would that be? It's the exact same data. The install is about 50GB in=
 size. Is there something wrong with postgres 16, or did some settings sign=
ificantly change, that I need to know about? I went over all the changelogs=
, nothing stood out as relevant to this, but that might be a lack of experi=
ence on my end.

Parallel vacuum arrived in PostgreSQL 13, and that uses "dynamic
shared memory" to share state between workers, and assuming
dynamic_shared_memory_type=3Dposix, that means shm_open(), which opens
files under /dev/shm on Linux.