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From Olav Sandstaa <o...@sun.com>
Subject Re: Performance regression after check-in on DERBY 2537 (SVN 531971)
Date Thu, 26 Apr 2007 20:52:05 GMT
To see the effect of this in a different environment I started a similar 
test running with IBM 1.5 VM on Linux. Unfortunately, the machine I 
decided to use was a shared server so during part of the test run some 
other testing have been running in parallel. I plan to try to re-run 
these tomorrow.

But anyway, I am attaching the graph even if it is not correct. It seems 
that the negative effect of this patch is much less when running on the 
IBM VM/Linux (the last part of the second curve I expect was run in 
parallel with some other testing). So if anyone is looking into this and 
using a different VM (or OS) than I did they might not see the large 
drop I see in my tests.


Mike Matrigali wrote:
> Are these tests checked in so that I can run them in my environment?
> Olav Sandstaa wrote:
>> The two last days I have seen a performance regression in some of the 
>> performance tests I run. For some of the tests the reduction in 
>> throughput is about 15 percent. It seems like the regression is 
>> introduced by the latest check-in on DERBY-2537, svn 531971.
>> I have attached a graph showing the throughput I get when running 
>> single-record select operation on a table. The queries use a 
>> secondary index for finding the record to select. The test has been 
>> run with 1 to 20 concurrent client against embedded Derby. I have run 
>> the test with and without SVN 531971. As the graph shows, the 
>> performance reduction is between 12 and 15 percent for all runs.
>> The schema looks like this:
>>  CREATE INDEX nonprimary_index ON t1 (sec_id)
>> Each query do the select on the secondary index and retrieves the 
>> data field (a CHARACTER(100) field).
>> I would expect some of the changes done in the patch to have some 
>> influence on the performance, but not in the order of 10-15 percent.
>> The tests are run on a 2 CPU Opteron server running Solaris 10 and 
>> JDK 6.
>> Olav
>> ------------------------------------------------------------------------

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