Re: pg_multixact/members growing - Mailing list pgsql-general

From Tom Lane
Subject Re: pg_multixact/members growing
Date
Msg-id 17164.1527018567@sss.pgh.pa.us
Whole thread Raw
In response to pg_multixact/members growing  (Tiffany Thang <tiffanythang@gmail.com>)
Responses Re: pg_multixact/members growing  (Thomas Munro <thomas.munro@enterprisedb.com>)
List pgsql-general
Tiffany Thang <tiffanythang@gmail.com> writes:
> Our pg_multixact/members directory has been growing to more than 18GB over
> the last couple of months. According to the documentation, the files in
> there are used to support row locking by multiple transactions and when all
> tables in all databases are eventually scanned by VACUUM, the older
> multixacts are removed. In our case, the files are not removed.

Hmm.  What does pg_controldata tell you about NextMultiXactId,
NextMultiOffset, oldestMultiXid, oldestMulti's DB?
Are pg_clog/ or pg_subtrans/ or pg_multixact/offsets/ getting large?
Is there anything at all in pg_twophase/?  Is this system a replication
master, and if so are any of its slaves lagging behind?

> Any
> suggestions what I should do to purge the files automatically? Can old
> files since the last reboot be manually removed?

I wouldn't do that.  Much safer to figure out what's blocking automatic
cleanup so you can fix the root cause.

            regards, tom lane


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