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From Dyre.Tjeldv...@Sun.COM
Subject Re: exponential increase in insert time
Date Sun, 07 Oct 2007 15:16:07 GMT
sudhakar <sudhakar@co.brazos.tx.us> writes:

> I'm using embedded derby in a Java SE application with OpenJPA. The
> applications parses a text file and creates JPA entity objects which it
> then turns around and persists in the embedded derby database using JPA.

A general observation: The more fancy frameworks you put between your
code and the jdbc/SQL calls, the harder it will be to identify
performance problems. It's the price you pay for ease of
development. There is no free lunch I'm afraid. 

> It starts of with inserting about 15 records per second and
> exponentially drops down to about one record every 25 seconds by the
> 400th record. I haven't tuned any of the derby parameters. 

You should definitely swing by the Derby web-site and make sure you
have done all the simple stuff. What you're describing sounds
unreasonable to me, but there is really no way to tell unless you say
how large your records are, and what the database schema looks like.

>> Before I
> started getting into that I wanted to run this by here to find out if
> this is the out-of-box expected performance. It doesn't look right. The
> insert time per record increases exponentially.
>
> Can someone confirm that if something is awfully wrong here and how I
> can go about troubleshooting this. The text file is about 90000 records.
> So this exponential performance decrease would be completely
> unacceptable to the end-user.

Sounds like something is wrong, yes. One thing you could try is to
turn on logging of SQL statments (derby.language.logStatementText see
the Tuning Guide), to see what actually happens during the insert.

-- 
dt


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