From: Tom Lane <tgl@sss.pgh.pa.us>
To: =?utf-8?B?Q2hyaXN0aWFuIFNjaHLDtmRlcg==?= <christian.schroeder@wsd.com>
cc: Francisco Olarte <folarte@peoplecall.com>,
        "pgsql-general@lists.postgresql.org" <pgsql-general@lists.postgresql.org>,
        Eric Wong <eric.wong@wsd.com>
Subject: Re: Memory issues with PostgreSQL 15
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Comments: In-reply-to =?utf-8?B?Q2hyaXN0aWFuIFNjaHLDtmRlcg==?= <christian.schroeder@wsd.com>
	message dated "Tue, 28 May 2024 22:59:13 -0000"
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Date: Wed, 29 May 2024 14:43:41 -0700
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=3D?utf-8?B?Q2hyaXN0aWFuIFNjaHLDtmRlcg=3D=3D?=3D <christian.schroeder@wsd.=
com> writes:
> # ipcs -m

> ------ Shared Memory Segments --------
> key        shmid      owner      perms      bytes      nattch     status
> 0x04000194 35         postgres   600        56         19

> I am surprised to see this since I would have expected much more shared =
memory to be used by the database. Is there anything in the configuration =
that prevents the shared memory from being used?

SysV shared memory isn't that relevant to Postgres anymore.  Most
of what we allocate goes into POSIX-style shared memory segments,
which are not shown by "ipcs".  We do still create one small
fixed-size data structure in SysV memory, which is what you're
seeing here, for arcane reasons having to do with the lifespan of
the shared memory segments being different in those two APIs.

>> <2024-05-21 11:34:46 CEST - mailprocessor> ERROR:  could not resize
>> shared memory segment "/PostgreSQL.2448337832" to 182656 bytes: No
>> space left on device

This seems to indicate that you're hitting some kernel limit on
the amount of POSIX shared memory.  Not sure where to look for
that.

			regards, tom lane