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Re: Slow query after upgrades

From: Oliver Jowett <oliver(at)opencloud(dot)com>
To: Tom Duffey <tduffey(at)techbydesign(dot)com>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: Slow query after upgrades
Date: 2007-12-13 21:20:33
Message-ID: 4761A221.80604@opencloud.com (view raw or flat)
Thread:
Lists: pgsql-jdbc
Tom Duffey wrote:

> I'm leaving the old JDBC driver there for now but am wondering if anyone 
> has any ideas what I should look for to find a solution to this?  I 
> jProfiled the execution and it is indeed the JDBC query that is taking 
> significantly more time to execute with the newer driver in place.

Identify the slow query and build a testcase for that particular query 
and send it to the list?

Also, beware of counting blocking I/O time as CPU time when doing Java 
profiling. Probably, the Java side is just blocking waiting on the server.

There are server-side logging options you might want to look at too.

The most likely cause is that more recent drivers ("recent" is very 
relative here, I think it went in for the 8.0 driver?) use the extended 
query protocol which can result in different plans for some queries.

-O

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