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Exadata and the db_block_checksum parameter.

With Exadata version came the Unbreakable Linux Kernel for Exadata, which had been the stock EL5 redhat kernel prior to this version (2.6.18). With the unbreakable kernel came the opportunity to run the perf utility. This utility has the opportunity to see which functions are active inside an executable when there’s a symbol table. And the oracle database executable has a symbol table! One reason to do this, is to get a more granular overview of what the Oracle database is doing than the wait interface, especially to get a more detailed overview of what the database is doing in what is visible in the wait interface as ‘on cpu’.

Switching Back to Regular Listener Log Format

Did you ever miss the older listener log file format and want to turn off the ADR-style log introduced in 11g? Well, it's really very simple.


Oracle introduced the Automatic Diagnostic Repository (ADR) with Oracle 11g Release 1. This introduced some type of streamlining of various log and trace files generated by different Oracle components such as the database, listener, ASM, etc. this is why you didn't find the alert log in the usual location specified by the familiar background_dump_dest initialization parameter but in a directory specified by a diferent parameter - ADR_BASE. Similarly listener logs now go in this format:

NoSQL and Oracle, Sex and Marriage

At last week’s Dallas Oracle Users Group meeting, an Oracle DBA asked me, “With all the new database alternatives out there today, like all these open source NoSQL databases, would you recommend for us to learn some of those?”

I told him I had a theory about how these got so popular and that I wanted to share that before I answered his question.

My theory is this. Developers perceive Oracle as being too costly, time-consuming, and complex:

RMOUG and Hotsos

Recently I’ve spoken at the RMOUG training days 2013 in Denver (the mile high city). It was a first time for me to speak for the RMOUG and being in Denver. Thanks to the “sequestration” (federal budget cuts) the lines piled at immigration at Minneapolis (Minneapolis and Saint Paul, the twin cities) airport, and because my plane left more than one hour to late and my layover time was one hour and fifteen minutes, I tried to rebook my flight from Minneapolis to Denver. But, this flight turned out to be delayed too. This meant I was able to get on this flight!

Not “how”, but “why” should we upgrade to JDeveloper & ADF ?

Followers of the blog know I’m an Oracle database guy, but my current job also has me honing my newbie WebLogic 11g skills, setting up a number of servers to deliver ADF and Forms & Reports 11gR2 applications.

As you’ve no doubt heard, Oracle have just released the version of JDeveloper and ADF. I tried applying the patch to a WebLogic 11g (10.3.6) installation and it worked without any problems (see here).

Hotsos Revisited 2013 – Presentatie materiaal

Hierbij nog dank voor allen die aanwezig waren bij de weer gevulde, informatieve & gezellige avond tijdens “Hotsos Revisited 2013″. Wij presentatoren hebben genoten van het ambiance. Hier ook nog voor degenen die graag het nog een keer willen nalezen het presentatie materiaal van Toon, Jacco, Gerwin, Frits en mij… Presentatie materiaal in alfabetische volgorde: …

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Oracle Linux : Frequently Asked Questions (FAQs)…

I mentioned in a previous post that my company were planning to move all of our middle tier infrastructure and some of our Oracle databases to Oracle Linux running on a virtual infrastructure. That process is now underway.

Persuading the company to ditch Red Hat Enterprise Linux (RHEL) in favor of Oracle Linux took a bit of effort, partly due to some Fear, Uncertainty and Doubt (FUD) spread by one of the vendors we use. In the process of trying to counter the FUD I put together an Oracle Linux FAQ document. I thought it might come in handy for anyone else in a similar position, so I thought I would make it available on my site.

Ignoring hints

A hint is an instruction to the optimizer

This is what’s written in Oracle documentation. Instruction is defined as

a code that tells a computer to perform a particular operation

Which means Oracle CBO must obey the hints and must perform particular operation. The latter is hard to define correctly and explain precisely because it involves the logic of the block-box (what Cost Based Optimizer is). Some of the operations are mentioned in the standard Oracle documentation, some of them scattered across different places, and there are exceptions as usual. I think I’ll list here these cases which could lead to “ignoring hints” with the links to documentation/blogs.

Everyone should write/present because…

Following on from my post about the ACE program, Yuri from Pythian asked what I get out of presenting that makes it worthwhile. In this post I will tell a few little stories to explain why I think writing and presenting are important skills for people, regardless of their ambitions.


Public Appearances and Exadata Performance Training

I will be doing a lot of (Exadata) talking and teaching in the coming months. Here’s a list of events where you’ll see me speaking, teaching, hacking, learning and hopefully also drinking beer: