As a follow-up of my last post, I learned that creating traces is much simpler in 11g than I expected it to be. Dion Cho and Tanel Poder pointed me to some interesting links http://oraclue.com/2009/03/24/oracle-event-sql_trace-in-11g/ http://tech.e2sn.com/oracle/troubleshooting/oradebug-doc describing how to set up a trace event on one SQL_ID without need to do it on session level […]
Category: Oracle
What’s the difference between Larry Ellison and god?
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 […]
Extracting Oracle DDL from online redo logs or archived redo logs with DDLDUMP
The oracle-l mailing list made me try a new tool, created by David Litchfield. It’s called DDLDUMP V. 0.1 and extracts DDL from redo logs or archived redo logs, the output format is XML. Since it’s a windows .exe file for now, I had to use wine to test it, but it works flawlessly, and […]
Oracle srvctl does not remove EONS despite it’s documented (PRKO-2013)
srvctl in Oracle Grid Infrastructure 11g Release 2 has at least one discrepancy between docs and functionality. I saw EONS consuming lots of memory in a non-database grid installation, and wanted to get rid of it. (The eONS is used by Oracle Enterprise Manager to receive notification of change in status of components managed by […]
Oracle IMPDP, ORA-1555 and UNDO_RETENTION
Many topics are to be found on the web about IMPDP and UNDO_RETENTION. This one will become a more theoretical one, around the central question: Why, please why does a huge IMPDP fail with ORA-1555 if there is too less UNDO_RETENTION configured? Like so often, these questions come from a problem. I had to impdp […]
Oracle Grid Infrastructure: UDEV fixing ORA-15081: failed to submit an I/O operation to a disk
If you plan to install Oracle products, be prepared for surprise of random kind. 🙂 The new Grid Infrastructure is no exception of this rule: I tried to install it on a SuSE Linux Enterprise Server (SLES) 10. Quick facts about the setup: SLES 10 SP 2 64bit Oracle Grid Infrastructure 11.2.0.1 x86_64 all devices […]
Oracle Grid Infrastructure 11gR2: How to clean up to repeat root.sh
To clean up a tilted installation of Oracle Grid Infrastructure isn’t that intuitive. I had to do it today, and this is my collection what to do and what to read. It’s made for repeating root.sh, that’s not allowed to run twice or more times without cleaning up in between. So first have a look […]
Lecture about Database Technology Basics at Augustinus Gymnasium Weiden
This year, I will talk again about basics of DB technology for 9th grade of AGW (Augustinus Gymnasium Weiden, a secondary school) again. The same event has been a success in the last years, and it’s simply nice there. Nice? Please allow me a word about this school. They have an engaged teacher, Klaus Märker, […]
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 11g Adaptive Cursor Sharing does not work with PL/SQL?
Recently, there was trouble in the air. I migrated a database into 11g to enjoy adaptive cursor sharing, but it did not adapt cursors. In the trouble shooting process, I discovered the following: Bug 8357294: ADAPTIVE CURSOR SHARING DOESN’T WORK FOR SQL FROM PL/SQL Nice one. A short quotation from the bug text: PL/SQL has […]