From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jerry Sievers <gsievers19@comcast.net>
cc: pgsql-admin@lists.postgresql.org
Subject: Re: Does raising maintenance_work_mem get seen by an already running
 aucovac?
In-reply-to: <m0y1pqcxl9.fsf@comcast.net>
References: <m0y1pqcxl9.fsf@comcast.net>
Comments: In-reply-to Jerry Sievers <gsievers19@comcast.net>
	message dated "Wed, 25 Jan 2023 11:50:42 -0600"
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Date: Wed, 25 Jan 2023 16:36:03 -0500
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Jerry Sievers <gsievers19@comcast.net> writes:
> There's a long running anti-wrap autovac that we'd rather let finish but
> on the server instance, I found maintenance_work_mem rather low and thus
> raised it in postgresql.comf, reloaded and confirmed that my interactive
> session saw the change.

> Can a running autovac make use of this or should I either wait it out or
> cancel and let it restart when ready?

Looks like an autovac worker will notice postgresql.conf changes once
per table:

    /*
     * Perform operations on collected tables.
     */
    foreach(cell, table_oids)
    {
        ...

        /*
         * Check for config changes before processing each collected table.
         */
        if (ConfigReloadPending)
            ProcessConfigFile(PGC_SIGHUP);

If it is stuck on a particularly enormous table, you might be best off
to kill it, but otherwise I'd let it go.

			regards, tom lane