Load Testing

This post is a mixture of experiences from a recent project and an overview on how to use RAT in a project. Real Application Testing (RAT) is a licensed feature for the Enterprise Edition (EE) of the Oracle database. It was released on 11g, but can be used to test migration of databases from 9i and 10g to 11g (assuming that the source databases have a required version/patch). The term Real is, I reckon, used to hint at a more authentic testing process. The tests are executed based on a capture from a real production system. ...

For the second time I have been involved with a proof of concept (PoC) where testing of an alternative hardware platform was the goal. Common for both PoCs were: The other option was Exadata Real Application Testing (RAT) was used to replay production recordings on the new hardware. And for the second time I have concluded that sales people take this too easy. It is not easy and assuming you will outperform previous platform just because you have a bunch of less expensive flash disks, cache cards, and more is arrogant at best. ...

I learned something very important when doing testing with Hammerora. The documentation is quite good and has a simple, but important point, the importance of planning and preparation. To quote the documentation for Oracle OLTP testing: Planning and Preparation is one of the most crucial stages of successful testing but is often overlooked. Firstly you should fully document the configuration of your entire load testing environment including details such as hardware, operating system versions and settings and Oracle version and parameters. Once you have fully documented your configuration you should ensure that the configuration is not changed for an entire series of measured tests. This takes discipline but is an essential component of conducting accurate and measured tests. ...

Last week I was running load tests in between other tasks on my agenda. As stated in previous post I wanted to compare performance, as measured by load testing tools, on an old SAN and a new one, EVA and 3PAR respectively. I ran two types of tests, the OLTP test and the SIMPLE test: orion -run oltp -num_disks 50 orion -run simple -num_disks 50 Following are charts from the ORION OLTP test with “num_disks” equal to 50. ...

The current customer is migrating from EVA storage to 3PAR, and inspired by some discussions on Twitter between @yvelikanov, @martinberx, @kevinclosson, @martinDBA, and others I decided to try out some free tools for load testing of Oracle servers. I can hardly tune a SQL statement without getting philosophical about it, so especially this first part is a bunch of thoughts I had when starting out. There are a lot of discussions on the usability of such tools; are the measured performance any close to the reality? The load these tools generate is more or less synthetic. One tool that stands out from the crowd is the Real Application Tool (RAT), but RAT requires an extra license from Oracle. With RAT you can capture real load on a production system and replay it on a test system with new or upgraded hardware or configuration. The reports generated in Enterprise Manager lets you compare the performance of old and new system so clearly that even your CEO can understand it. You cannot get much closer to reality than with RAT, but as said, it costs money and time to set it up. [And for a change I will not whine much more on the fact that SMBs around here do not invest in these licensed packages that makes the life of the DBA easier.] ...