Re: Beginning tuning

From: Oliver Jowett <oliver(at)opencloud(dot)com>
To: Phillip Mills <pmills(at)systemcore(dot)ca>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: Beginning tuning
Date: 2007-11-07 21:24:44
Message-ID: 47322D1C.4040405@opencloud.com
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Phillip Mills wrote:

> (Regarding the main problem, none of my threads are reported in a
> blocked state, leading to my focus on I/O.)

BTW, this is because Sun JVM thread dumps and JVMPI/JVMTI generally
consider a thread currently in a native method to be "running"
regardless of what it's actually doing. In the case of a network read
(implemented as a native method), it's actually most likely to be
blocked in the kernel waiting on more data from the server. Makes for
fun when profiling, I've had to build tools to explicitly exclude "is
probably blocked" native methods from profile results to get anything
useful on systems that are mostly I/O bound :(

-O

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