| From: | Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)uk> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Merlin Moncure <mmoncure(at)gmail(dot)com>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile |
| Date: | 2012-05-26 14:09:29 |
| Message-ID: | alpine.LRH.2.02.1205261505050.12723@calx046.ast.cam.ac.uk |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Sat, 26 May 2012, Robert Haas wrote:
> This theory is seeming fairly plausible - how can we test it?
>
> How about trying it with synchronize_seqscans = off? If the
> synchronized-seqscan logic is causing contention on the buf mapping
> locks and individual buffer locks, that should fix it.
Turning off synch seq scans doesn't help either. 18 sec multithreaded run
vs 7 sec single threaded.
S
*****************************************************
Sergey E. Koposov, PhD, Research Associate
Institute of Astronomy, University of Cambridge
Madingley road, CB3 0HA, Cambridge, UK
Tel: +44-1223-337-551 Web: http://www.ast.cam.ac.uk/~koposov/
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Stephen Frost | 2012-05-26 14:24:40 | Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile |
| Previous Message | Robert Haas | 2012-05-26 13:44:12 | Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile |