Execution Time with a Statement 1 ms with a PreparedStatement 3 minutes
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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:
{noFormat}
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
{noFormat}
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