Posts Categorized: Pythian
Finding duplicates with RANK – If you’ve made the mistake of forgetting a primary key on your table, it can be frustrating to find a way to delete all of the duplicate rows without deleting the initial instances. This query selects all of the ‘extra’ rowids and removes them.
Well I have been back from Collaborate 2006 for over a week now and decided that I should also make my presentation available from the Pythian web site. While there I participated in three sessions. I joined Michael Abbey, Ian Abramson, and Carl Dudley on a panel for the Non-Oracle DBA. My first presentation was PostgreSQL for the Oracle DBA. My second solo-presentation was Oracle 10g Data Pump 101.
If you have the ability to combine disk spindles at both the SAN level and Oracle (ASM) level, which one is better? Should you combine all your spindles on the SAN and present 1 big disk to OS and give that to ASM? Or should you present each individual disk spindle to ASM and let ASM do the mirroring? The disk group with 2 disks is slower! Those results are consistent, and confirmed with diagnostic output from iostat. You may start to wonder why would 2 be slower then 1. It should be twice as fast!
Did anyone else notice this interesting e-week article titled The Downside of Certification? It immediately reminded me of an article written by Pythian team lead and datawarehousing architect Rob Hamel titled “Get Down with OCP: Evaluating DBA Job Applicants in an OCP World”. What Rob noticed in 2004 was that certification can mask a certain type of incompetence from a casual technical evaluation process.
Tip of the hat to Eddie Awad who does some noticing and some digging to confirm that lnnvl(), a function that provides functionality similar to ANSI “Is Not True” and can be used to return boolean TRUE whenever the predicate to the function is either NULL or FALSE is now supported in 10GR2.
Here is an article I posted on the Oracle-L mailing list recently. Much to my surprise, people liked it enough that they asked to see it here, too.
This was written in response to the question: “How do you edit an SPFILE?”
I skipped the general session but heard there was talk about Oracle unlimited support. Basically someone else summarized it as Oracle will take your money as long as you want to give it to them. So no more “de-supported” products. Of course, old products will not get bug fixes unless you really really really pay for it.
Good luck to acquaintances (dare I say friends? we have never met in person!) of mine Jonathan Lewis and Doug Burns who are presenting on April 27th at the UKOUG Northern Server Technology Day.
After I actually woke up I found myself attending a session about LogMiner by Chet Watmough. Log Miner in my opinion is a vastly under-used utility. It has such great versatility. Chet showed some techniques to add additional logging. By inserting the client info information into a dummy table, just to produce a record in the redo stream, he can identify who did what.
So I made my decision and went to “RAC & ASM best practices” presented by Kirk McGowan of Oracle. I wanted to see how far the documentation / common sense was from what will actually work. It wasnt that far from the docs, which is good. It means Oracle got it right.