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From "Steffen Kuche (Created) (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DERBY-5555) Execution Time with a Statement 1 ms with a PreparedStatement 3 minutes
Date Fri, 23 Dec 2011 12:06:30 GMT
Execution Time with a Statement 1 ms with a PreparedStatement 3 minutes

                 Key: DERBY-5555
                 URL: https://issues.apache.org/jira/browse/DERBY-5555
             Project: Derby
          Issue Type: Bug
            Reporter: Steffen Kuche

Sounds incrediable? Test it by yourself with the attached program.

The issued reased up because of AMQ-3644, but it is actually a derby problem so I post the
issue here as well.

Derby writes multiple gigabyte of temporary files in its tmp directory during one select statement.
Afterwards these temporary files are deleted and rebuild by the next Statement. 

You can find a Test-Program (import it as a Maven-Eclipse project) which reproduces this issue.
This program creates a derby database with a the activemq Message table and fills it with
data (2000 Messages, this can take several hours). I assumed 3MB for one message as our messages
contain same binary data and has an average size of 3MB.

After the database is built one time a Statement and one time a PreparedStatment is used to
retrieve the next messages.
The Statement takes about 1 ms and the PreparedStatement about 258805 ms. Also the second
PreparedStatement takes as much time.

Here are the temporary files created by derby during the select Statement:
insgesamt 5,4G
 287M 2011-12-23 09:48 T1324630116288.tmp
 287M 2011-12-23 09:49 T1324630116289.tmp
 287M 2011-12-23 09:49 T1324630116290.tmp
 287M 2011-12-23 09:49 T1324630116291.tmp
 287M 2011-12-23 09:49 T1324630116292.tmp
 287M 2011-12-23 09:49 T1324630116293.tmp
 287M 2011-12-23 09:50 T1324630116294.tmp
 287M 2011-12-23 09:50 T1324630116295.tmp
 287M 2011-12-23 09:50 T1324630116296.tmp
 287M 2011-12-23 09:50 T1324630116297.tmp
 287M 2011-12-23 09:51 T1324630116298.tmp
 287M 2011-12-23 09:51 T1324630116299.tmp
 287M 2011-12-23 09:51 T1324630116300.tmp
 287M 2011-12-23 09:51 T1324630116301.tmp
 287M 2011-12-23 09:51 T1324630116302.tmp
 287M 2011-12-23 09:52 T1324630116303.tmp
 287M 2011-12-23 09:52 T1324630116304.tmp
 287M 2011-12-23 09:52 T1324630116305.tmp
 284M 2011-12-23 09:52 T1324630116306.tmp

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