e i g h t - c u b e d . c o m 

Database performance

I arrived back from Atlanta to find that the performance issue that the business has been having with a new data warehouse running Oracle 9i has escalated to high management visibility.

When I left prior to last week, the situation was that the DBAs had been given a test query that had been running in an acceptable time prior to the introduction of RAC. When RAC was enabled, the performance went down the drain. After tweaking the database, the performance improved from 4 hours to 4 minutes, telling me that the systems were fine, and any performance enhancements would be achieved by application and/or database tuning.

I arrive back to find that I'm being asked to reconfigure the entire cluster.

The reconfiguration will provide a private network to run RAC lock traffic.

A large part of the problem here is that the application developers have experience with the performance of Rdb on OpenVMS, and are expecting similar performance from Oracle 9i. It's my contention that they will never achieve it. Rdb takes advantage of too many low level features of OpenVMS (for example, OpenVMS's distributed lock manager), while Oracle 9i, being generic code that will run on nearly any platform, has its own built in lock manager, which uses TCP/IP as the transport protocol. Memory Channel II verses gigabit ethernet. There is no contest.

Fortunately, the machines this is running on are GS160s, which are very easy to reconfigure, and with a little assistance from the Network Engineering Team, I should be able to make the magic happen in a couple of hours tonight.

One other note. Oracle's support has been poor. And I mean poor. HP stepped up to the plate, and have been tireless in attempting to support us. At least one vendor values customer relations.