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Re: performance config help

From: Bob Dusek <redusek(at)gmail(dot)com>
To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
Cc: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: performance config help
Date: 2010-01-11 21:23:39
Message-ID: 61039b861001111323g531a5d68q1f59171d926aefef@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
>
>
> I haven't been keeping up on the hardware, so I defer to you on
> that.  It certainly seems like it would fit with the symptoms. On
> the other hand, I haven't seen anything yet to convince me that it
> *couldn't* be a client-side or network bottleneck, or the sort of
> lock contention bottleneck that showed up in some of Sun's
> benchmarks.  If it were my problem, I'd be trying to rule out
> whichever one of those could be tested most easily, iteratively.
>
>
How do I learn more about the actual lock contention in my db?   Lock
contention makes some sense.  Each of the 256 requests are relatively
similar.  So, I don't doubt that lock contention could be an issue.  I just
don't know how to observe it or correct it.  It seems like if we have
processes that are contending for locks, there's not much we can do about
it.

Also, as you suggested, identifying what queries are taking most of
> the time and trying to optimize them is a route that might help,
> regardless.
>

We often undertake query optimization.  And, we often learn things about our
app or make small performance gains from it.  Sometimes, we are even able to
make big changes to the application to make large gains based on how we see
queries performing.

So, I agree that it's a good thing.  However, query optimizing is tough,
since you can't necessarily predict the sizes of your tables in a real-time
system that is used differently by different users.


> -Kevin
>

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