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January 2009

Runstats utility

A variation on Tom Kyte's invaluable RUNSTATS utility that compares the resource consumption of two alternative units of work. Designed to work under constrained developer environments and builds on the original with enhancements such as "pause and resume" functionality, time model statistics and the option to report on specific statistics. ***Update*** Now available in two formats: 1) as a PL/SQL package and 2) as a free-standing SQL*Plus script (i.e. no installation/database objects needed). January 2007 (updated October 2011)

Row Migration can Aggravate Contention on Cache Buffers Chains Latch

AWR Wait EventsOne of my customers has an Oracle based system with a large number of concurrent users. For time to time, the users would report that the system would 'grind to a halt'. Examination of AWR data showed lots of time spent waiting on latch: cache buffers chains (I discussed how to graph AWR data in Excel in a previous blog entry, which is how I produced this graph of database wait events).

communication, clarity and the benefits of real names

--- just found this one. I wrote it in Jan 09 and didn't publish it: I think I planned on adding a lot of links and ran out of time. Publishing it under the original date, but if you've been here before, you didn't miss it the first time. I slipped it in ... oh no! I've cheated on the version control system !! :)For the past month, my work has been somewhat disconnected from the database.

Migrate from Windows XP 64bit to Ubuntu Intrepid Ibex 8.10 64bit

I’ve been using the newest and the greatest version of Ubuntu (Intrepid 8.10) for almost a month now and I’m happy with it </p />

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Oracle memory troubleshooting, Part 1: Heapdump Analyzer

When troubleshooting Oracle process memory issues like ORA-4030’s or just excessive memory usage, you may want to get a detailed breakdown of PGA, UGA and Call heaps to see which component in there is the largest one.

The same goes for shared pool memory issues and ORA-4031’s – sometimes you need to dump the shared pool heap metadata for understanding what kind of allocations take most of space in there.

The heap dumping can be done using a HEAPDUMP event, see for syntax.