Posts by Christo Kutrovsky

Bind Peeking, Ad Hoc Queries, Stable Performance

I got to troubleshoot an amazing situation a few weeks ago. I think it is essentially inconceivable that allowing a single query to run on your system can flip another query’s plans and cause major performance issues (and in this case even downtime!). Sometimes it’s coincidence, sometimes it’s load, and sometimes it’s a single ad hoc query with a new predicate that starts the slowly-ticking time bomb. Here is how it happens and how to fix it.

Pythian Goodies: The Answer to Free Memory, Swap, Oracle, and Everything

I gave this talk covering the different types of memory, how to monitor memory, and how to optimally use it with Oracle at the UKOUG, I have since received requests to post the slides online. Instead of just posting the PowerPoint I took some time to give the presentation again (internally here at Pythian) and this time we recorded the session and are posting it in a variety of formats. This is a bit of a departure from the typical Pythian Goodies, in that it is scripted, and there is a lot of content here in the whitepaper.

Off to OpenWorld!

Just a quick note to say I’m leaving today for San Francisco to attend Oracle OpenWorld. I’ll be making my presentation on Thursday at 14:30, in Room 304. Look for IOUG: Oracle Database 11g –The Perfection of a Masterpiece (Session ID: S291070).

Metalink Note on Datafile Recovery Will Corrupt Database

Thinking I had something new, I wrote this article about recovering deleted files. However, it turns out Frits Hoogland had already blogged about recovery of deleted files on linux, as Frits pointed out in a comment on my blog, where he also mentioned a metalink note on this matter. The procedure outlined in the note describes how to recover the deleted file and put it in the same location as the deleted file. The problem is that it doesn’t include offlining/onlining the file, so the database ends up with two distinct copies of the file.

How Will 11g Change Oracle Datacenters?

Let’s focus on what 11g is all about. The main message I got is that Oracle 11g is the consumer release. According to Mr. Phillips, what this means is that Oracle has listened to its clients and has worked in the areas that the consumers needed the most. The fact that Ari Kaplan, the president of the IOUG, was on stage during the launch speaks for itself. As for what’s new in 11g, three major features come to mind…

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