Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Merlin Moncure <mmoncure(at)gmail(dot)com>
Cc: Stephen Frost <sfrost(at)snowman(dot)net>, Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)uk>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile
Date: 2012-05-25 16:38:01
Message-ID: 23608.1337963881@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Merlin Moncure <mmoncure(at)gmail(dot)com> writes:
> On Fri, May 25, 2012 at 11:17 AM, Stephen Frost <sfrost(at)snowman(dot)net> wrote:
>> Didn't we implement a system whereby this is exactly what we intend to
>> happen on the read side- that is, everyone doing a SeqScan gangs up on
>> one ring buffer and follows it, which we felt was going to dramatically
>> improve performance in some cases?

> yeah:
> ...
> I wonder if the logic here is just being too strict...

I don't recall how much evidence there is behind the NBuffers/4 threshold.
Maybe that needs some tuning?

regards, tom lane

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Sergey Koposov 2012-05-25 16:44:56 Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile
Previous Message Tom Lane 2012-05-25 16:34:54 Re: Interrupting long external library calls