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From "Myrna van Lunteren (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-4227) performance degradation of with simple queries & no data retrieval
Date Wed, 13 May 2009 00:36:45 GMT

     [ https://issues.apache.org/jira/browse/DERBY-4227?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Myrna van Lunteren updated DERBY-4227:

    Attachment: scanperf.java

Small repro class that will get the system time in a long before and after selecting 10000
rows and only counting the number of rows in the resultset, then prints out the diff.

To run: compile,add class to classpath, run (for instance redirecting output to a file), remove
derby.log and wombatC, run again.

> performance degradation of with simple queries & no data retrieval
> ---------------------------------------------------------------------------
>                 Key: DERBY-4227
>                 URL: https://issues.apache.org/jira/browse/DERBY-4227
>             Project: Derby
>          Issue Type: Bug
>    Affects Versions:,
>            Reporter: Myrna van Lunteren
>         Attachments: scanperf.java
> I have been executing some non-contributed (and not easily contributable) performance
tests, and found that across the board, with the exception of some blob streaming and complicated
queries, performs significantly worse from
> I've turned one of these tests into a little repro script.
> It's decidedly hokey, but if you execute this repeatedly (removing the wombatC db and
derby.log each time) you'll likely find the same. I executed this on an MS-Windows 2000 machine,
with ibm 1.5. jvm.
> As a quick comparison, I got the following data out of executing the repro 4 times with
a fairly recent build (706492),, and Time is the elapsed time
printed out at the  end by the repro.
> version
> 1st run      187               219             328
> 2nd run     172               172             328
> 3rd run       203              234             313
> 4th run       187               281            344
> We should identify why a simple select without actually fetching the data would do so
much worse with

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