Some time ago, I saw a great presentation of Cary Millsap: „Thinking clearly about performance”. It was obviously relevant for our internal developers, so he unhesistantly granted me permission to reproduce some of his ideas for us. Cary, thank you very much! Here you can see, what I made out of the topic, mostly for […]
Tag: performance
Oracle 12c InMemory – don’t stop thinking about performance
Oracle has released its new database version 12.1.0.2 that includes the famous in-memory column store. InMemory option promises a big advantage for OLAP-like work loads by keeping table contents in a columnar in-memory structure. InMemory is not new, they did that for decades, but the interesting part is “columnar”. There’s much writing about that on […]
Oracle 12.1.0.2 with In Memory Option available for Linux
As of today, the Oracle Database 12.1.0.2 with InMemory Columnar Store is available at https://edelivery.oracle.com. According to the price list of July 10th, it will be sold as an option for Enterprise Edition (Exadata NOT mandatory), for US$ 23,000 per CPU (calculation like EE). Hope it will do well, beta demos were extremely impressive. Yours […]
Effecting Oracle Miracles With Standard Edition And Statspack (=without AWR)
For the most time, I have to work with Oracle Standard Edition database systems without any chance to use AWR, ASH or Diagnostics Pack in general. But performance problems have to be analysed in budget environments as well, and many people are complaining about Oracle’s policy in this area. But in my experience, it’s also […]
Oracle 11.2: Cursor Mutex S wait event and too many (2^30) child cursors
Once again, there was a lesson to be learned about the Oracle RDBMS. The occaison was a direct upgrade from Enterprise Edition 10gR2 to EE 11gR2, the application was kept untouched for good reason. Problem After running the new version for two hours, everything became incredibly slow, and the CPU load on the DB server […]
Oracle: How to create a good execution plan
Sometimes you simple need to know whether a statement is fast or not, or why it is slow. (Sadly, it seems like virtually nobody wants to know why a statement is fast, but that’s another story…) Do not use EXPLAIN PLAN in such cases, it does not (can not) deal bind variables right. I’ve got […]
Oracle Explain Plans or Execution Plans: Guess or Reality?
Oracle finally desupported the rule-based optimizer with version 10g. Since 9i, users are good adviced to make themself familiar with the cost-based-optimizer (CBO). In order to understand what happens with your statement after parsing with CBO involved, and to be able to tune your queries, displaying, understanding and optimizing explain- or execution plans is essential. […]
Creating Oracle AWR reports quicksheet
For comparing, classifying, benchmarking and forecasting databases, Oracle’s Automatic Workload Repository (AWR) is neat. (But remember! You will need a diagnostics pack license for that as described here and here – if you need a free technology for performance monitoring, consider using Craig Shallahamer’s OSM toolkit.) This post simply describes the package calls to create […]