[PROPOSAL] Drop orphan temp tables in single-mode

From: Arthur Zakirov <a(dot)zakirov(at)postgrespro(dot)ru>
To: Postgres hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Cc: Grigory Smolkin <g(dot)smolkin(at)postgrespro(dot)ru>
Subject: [PROPOSAL] Drop orphan temp tables in single-mode
Date: 2019-03-07 09:46:06
Message-ID: b467480e-445a-d437-9eb3-b9927498964a@postgrespro.ru
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Hello hackers,

In some cases if PostgreSQL encounters with wraparound PostgreSQL might
leave created temporary tables even after shutdown.

This orphan temporary tables prevent VACUUM to fix wraparound. It is
because in single mode VACUUM considers orphan temp tables as temp
tables of other backends.

Grigory reported that one of our client did stuck with fixing wraparound
by because he didn't know that he has orphaned temp tables left by a
backend after wraparound.

This patch fixes the issue. With it VACUUM deletes orphaned tables in
single mode.

See also thread in general (I'm not sure that orphan temp tables were
cause here though):
https://www.postgresql.org/message-id/CADU5SwN6u4radqQgUY2VjEyqXF0KJ6A09PYuJjT%3Do9d7vzM%3DCg%40mail.gmail.com

If the patch is interesting I'll add it to the next commitfest and label
it as 'v13'.

--
Arthur Zakirov
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company

Attachment Content-Type Size
vacuum_drop_orphan_temp.patch text/x-patch 3.1 KB

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