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. […]
Category: Oracle
What’s the difference between Larry Ellison and god?
Get Oracle User DDL with dbms_metadata
Sometimes you have to recreate a user in a DB, and you like it to be the same as before again. To have its DDL at hand is usually rather convenient. DBMS_METADATA is a great toolbox to get it, my example is just a short but hopefully useful excerpt of its possibilities: set long 200000 […]
Oracle 11g JDBC driver hangs blocked by /dev/random – entropy pool empty
On a headless (=without console) network server, the 11g JDBC driver used for (java) application connect may cause trouble. In my case, it refused to connect to the DB without any error, trace or log entry. It simply hung. After several hours, it connected one time, and freezed again. Remote debugging done by the development […]
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 […]
“Basics of Database Technology” again
Tomorrow, there will be a version 2.0 of a lecture from last year, again for 9th-formers of Augustinus Weiden. The handout and the presentation are online now, we will see what Friday brings. Usn […]
New job in 2009 – looking back at A.T.U
After working at A.T.U Auto-Teile-Unger headquarters for over six years, there’s a new challenge calling on January 1st, 2009, and hopefully, it’s for a long time again. I guess it’s a good time to look back: […]
Oracle: Remove scheduler jobs in a loop
If there are too much scheduler jobs in an Oracle database, the CJQ process may die unexpectedly. This has nothing to do with job history, not, it’s the number of jobs known to the system. In my experience, the critical number is somewhere around 32.000 in 10.2 64bit. By the way, that’s the solution for […]
Oracle: How to stop a (MTS) dispatcher process – mad behaviour of ALTER SYSTEM
Manually stopping a dispatcher process is one of the things I have to look up each time, since it’s needed not that often. And, the word “dispatcher” does not appear in the command line! 🙂 alter system shutdown immediate ‘D000’; where “D000” is the dispatcher process name selected from v$dispatchers or gv$dispatchers. (In the latter […]
Oracle 10g Data warehouse ORION benchmark, size 20TB, 1200MB per second
During the last days, I have had the opportunity to test and benchmark a data warehousing hardware, that’s really fast for its money. It’s not suitable for real/available production, since it depends on disk striping over a bunch of components, but I considered it as a good way to push the limits a bit. Result: […]
Attended “Reactive Performance Management” with Craig Shallahamer
Monday and today (Tuesday) I attended a 2-days Oracle University class with Craig Shallahamer from OraPub, taking place in Munich. Honestly, I have had no expectations at all, so there has been nothing to be crestfallen or to be fulfilled. I just was looking forward to the one or other hint how to find the […]