| From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
|---|---|
| To: | Peter Geoghegan <pg(at)heroku(dot)com> |
| Cc: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Wait free LW_SHARED acquisition |
| Date: | 2013-09-27 00:03:20 |
| Message-ID: | 20130927000320.GC29658@awork2.anarazel.de |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 2013-09-26 16:56:30 -0700, Peter Geoghegan wrote:
> On Thu, Sep 26, 2013 at 3:55 PM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> > We have had several customers running postgres on bigger machines report
> > problems on busy systems. Most recently one where a fully cached
> > workload completely stalled in s_lock()s due to the *shared* lwlock
> > acquisition in BufferAlloc() around the buffer partition lock.
>
> That's unfortunate. I saw someone complain about what sounds like
> exactly the same issue on Twitter yesterday:
Well, fortunately there's a solution, as presented here ;)
There's another bottleneck in the heaps of PinBuffer() calls in such
workloads, that present themselves after fixing the lwlock contention,
at least in my tests. I think I see a solution there, but let's fix this
first though ;)
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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