Re: O(n) tasks cause lengthy startups and checkpoints - Mailing list pgsql-hackers

From Tom Lane
Subject Re: O(n) tasks cause lengthy startups and checkpoints
Date
Msg-id 1058306.1680467858@sss.pgh.pa.us
Whole thread Raw
In response to Re: O(n) tasks cause lengthy startups and checkpoints  (Nathan Bossart <nathandbossart@gmail.com>)
Responses Re: O(n) tasks cause lengthy startups and checkpoints
List pgsql-hackers
Nathan Bossart <nathandbossart@gmail.com> writes:
> It's been a little while since I dug into this, but I do see your point
> that the wraparound risk could be higher in some cases.  For example, if
> you have a billion temp files to clean up, the custodian could be stuck on
> that task for a long time.  I will give this some further thought.  I'm all
> ears if anyone has ideas about how to reduce this risk.

I wonder if a single long-lived custodian task is the right model at all.
At least for RemovePgTempFiles, it'd make more sense to write it as a
background worker that spawns, does its work, and then exits,
independently of anything else.  Of course, then you need some mechanism
for ensuring that a bgworker slot is available when needed, but that
doesn't seem horridly difficult --- we could have a few "reserved
bgworker" slots, perhaps.  An idle bgworker slot doesn't cost much.

            regards, tom lane



pgsql-hackers by date:

Previous
From: Daniel Gustafsson
Date:
Subject: Re: [PATCH] Add `verify-system` sslmode to use system CA pool for server cert
Next
From: Nathan Bossart
Date:
Subject: Re: O(n) tasks cause lengthy startups and checkpoints