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Jun 17, 2008 at 01:36 PM

Performance problems after Update from 7.6.00.37 to 7.6.03.15

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Hi,

after the Update from 7.6.00.37 to 7.6.03.15 in our live system we noticed a lot of performance problems. We have tested the new version before on our test system, but there don't noticed effects like this.

We have 2 identical systems (Opteron 64 bit, openSuse 10.2) with log shipping between them. We updated first the standby system, switched from online to standby (with copy of cold log) and started the new server as online system. After that we run a complete backup (runtime: 1 hour) for starting a new backup history and for activating autolog. Then

With the update we changed USE_OPEN_DIRECT to YES, but the performance of the system was very slow afterwards. After the backup it remains at a high load average (> 10, previous system had about 2-4), with nearly 100% of CPU usage for the db kernel process.

Next day we switched USE_OPEN_DIRECT back to NO. The system first runs better, but periodically rises up to a load average of 6 and slow down the performance of various applications (somebody says about 10 times slower). Here we also noticed a high usage (now 200-300%) of the db kernel process.

Our questions are:

1. Has something basically changed from 7.6.00.37 to 7.6.03.15, so that our various applications (JDBC, ODBC and Perl/SQLDBC partially on old linux systems with drivers from 7.5.00.23) don't reach same performance as before?

2. Are there any other (new) parameters, which can help? Maybe reducing MAXCPU from 4 to 3 for reserving capacities for the system (there is only one maxdb instance running)?

3. Is the a possibility to switch back to 7.6.00.37 (only for worst case)?

I have made some first steps with x_cons, but don't see any anomalies on the first look.

Regards,

Thomas