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  • My first contact with the log miner

    I have never really played with log miner, but used it many times implicitly for streams. The need to get to grips with it arose when a developer created unrecoverable operations (i.e. something non-logging) in a QA system. I don’t want them to run the same in production so I had to find out who…

  • Restore table statistics

    UPDATE 230306 this post was originally written in December 2009. The examples have been verified & updated for Oracle 21.7.0, however there are most likely additional changes that have happened in the meantime that aren’t properly reflected here. Introduction The need to restore table statistics can be a common task for production DBAs. Let’s assume…

  • Recreate the standby controlfile when using ASM

    This is in reply to some work I was supposed to carry out over the weekend on a DR database. It could have been really simple, but it turned out it wasn’t. As part of a major migration I moved a 2TB database from OCFS to ASM, which worked really nicely with a Data Guard…

  • Explain plan doesn’t peek at variables

    I was trying to experiment with the 11g SQL Plan Management feature when stumbing across this. You will most likely go “ohh-of course it doesn’t” but I didn’t know it for sure until now. It’s another reason the expected explain plan differs from the actual explain plan, as discussed on the oracle-l mailing list recently.…

  • UKOUG Conference-session review part 3

    The final installment of this series deals with Tom Kyte’s top 10 features in 11.2 and Wolfgang Breitling’s “seeding statistics”. Tom Kyte – Top 10 new 11.2 features 1) dbms_parallel_execution: I was a little late so didn’t get the essence of this. Seems to automatically do what Tom described as “poor man’s parallelism” in his…

  • Let there be multipathing (when there wasn’t before)

    One of the projects I was working on recently couldn’t be finished as it should have been due to a lack of switch ports in the SAN. The QA database servers therefore only had single pathing to the storage whereas the production kit (thank god!) had multipathing enabled and configured correctly. UPDATE 221219: this document…

  • UKOUG conference 2009-session review part 2

    This is the second part of my review of UKOUG conference 2009, day 1. Check out the first part as well! This picks up exactly where I left part 1 after Tom Kyte’s session. Virtual Insanity I remained in hall 1 to see the great presentation of James Morle. I have to say that even…

  • Do not shut down ASM when dropping a disk

    I was doing some maintenance today with an ASM disk group (10.2.0.4.1 64bit on RHEL 5.3). UPDATE 221219: this post refers to software that has long gone out of support, the information therefore has been archived and should no longer be referred to. In a nutshell, we swapped disks in the FRA to increase the…

  • A day at UKOUG Conference in Birmingham

    What a great decision to go to UKOUG #tech_ebs on Monday! I’ve managed to see presentations from Wolfgang Breitling, James Morle and Tom Kyte (twice). So that was good. But the even better part was catching up with Julian Dyke, Piet de Visser (I promise I will read more of your blog!), David Kurtz, the…

  • Selectively purging the shared pool

    Another very useful thread has developed on the oracle-l mailing list. On a side note, this is really _the_ list to be subscribed to-there are so many experienced Oracle DBAs out that it’s pure joy. But I digress, back to the problem I often face when performance troubleshooting systems is to purge a SQL statement…