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From Olav Sandstaa <Olav.Sands...@Sun.COM>
Subject Re: Performance regression after check-in on DERBY 2537 (SVN 531971)
Date Mon, 30 Apr 2007 11:58:01 GMT
Attached is a slightly modified version of the test client found in 
DERBY-1961. The main change I have done is to add a secondary index to 
it that is used for the queries. Running this with two clients on a dual 
CPU machine running Linux and using IBM JVM 1.5 I see a drop in 
throughput of about 6 percent (down from 16656 tps to 15706 tps - 
average of five runs).

To run this client do:

1. Create and initialize database:

     java  TestClient2 -a initdb -u "jdbc:derby:/tmp/tulldb;create=true"

2. Run test (which does SELECT * FROM ... WHERE SEC_ID= X) with two 
client threads:

     java TestClient2 -a select -r 60 -c 2 -u "jdbc:derby:/tmp/tulldb"


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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