Re: huge memory of Postgresql backend process

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "James Pang (chaolpan)" <chaolpan(at)cisco(dot)com>
Cc: PostgreSQL mailing lists <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Subject: Re: huge memory of Postgresql backend process
Date: 2022-09-08 13:47:57
Message-ID: 3950547.1662644877@sss.pgh.pa.us
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"James Pang (chaolpan)" <chaolpan(at)cisco(dot)com> writes:
> We just switch from Oracle to PGV13, all of these tables got partition (256 HASH partition) , when UPDATE/DELETE ... WHERE . The memory increase verify quickly until >130M. not too much data in these tables. When we switch to PGV14.5 , test again, still see similar memory consumption issue.

I see no particular reason to think this is a bug. If you have a
lot of partitions, there is going to be a lot of metadata for them.
Moreover, HASH partitioning is effectively incapable of being
pruned, so that every query is going to touch every partition.
(IMO, hash partitioning is basically never a good idea.)

regards, tom lane

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