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

On Wed, May 30, 2012 at 4:16 PM, Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)uk> wrote:

> But the question now is whether there is a *PG* problem here or not, or is
> it Intel's or Linux's problem ? Because still the slowdown was caused by
> locking. If there wouldn't be locking there wouldn't be any problems (as
> demonstrated a while ago by just cat'ting the files in multiple threads).

You cannot have a traditional RDBMS without locking. From your
description of the problem, I probably wouldn't be using a traditional
database system at all for this, but rather flat files and Perl. Or
at least, I would partition the data before loading it to the DB,
rather than trying to do it after.

But anyway, is idt_match a fairly static table? If so, I'd partition
that into 16 tables, and then have each one of your tasks join against
a different one of those tables. That should relieve the contention
on the index root block, and might have some other benefits as well.

Cheers,

Jeff