Re: [PATCH] Improve performance of NOTIFY over many databases (v2)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Martijn van Oosterhout <kleptog(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PATCH] Improve performance of NOTIFY over many databases (v2)
Date: 2019-09-22 15:48:07
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

Martijn van Oosterhout <kleptog(at)gmail(dot)com> writes:
> On Mon, 16 Sep 2019 at 15:33, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> But do we care? With asyncQueueAdvanceTail gone from the listeners,
>> there's no longer an exclusive lock for them to contend on. And,
>> again, I failed to see any significant contention even in HEAD as it
>> stands; so I'm unconvinced that you're solving a live problem.

> You're right, they only acquire a shared lock which is much less of a
> problem. And I forgot that we're still reducing the load from a few
> hundred signals and exclusive locks per NOTIFY to perhaps a dozen
> shared locks every thousand messages. You'd be hard pressed to
> demonstrate there's a real problem here.

> So I think your patch is fine as is.

OK, pushed.

> Looking at the release cycle it looks like the earliest either of
> these patches will appear in a release is PG13, right?


regards, tom lane

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 2019-09-22 16:28:02 Re: Wrong sentence in the README?
Previous Message Jeff Janes 2019-09-22 15:45:05 Re: WAL recycled despite logical replication slot