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July 2012

Diagnosing SQL Performance Problems Webinar Followup

Thanks to everyone who joined me for part 1 of my Oracle SQL Performance webinar series! Embarcadero will be posting the recording within the next few days. In the meantime, I thought I'd post the slides and a few scripts that were shown.

Thanks again and I hope to see you again next month for part 2!

Presentation slides (PDF)
Scripts (ZIP)

Adaptive STAT lines in SQL trace

Lately I’ve been using SQL runtime execution statistics combined with SQL monitor for performance diagnostics and, honestly, almost forgot about SQL trace. So this note is not very useful to me but it might be to someone: along with ALL_EXECUTIONS option appeared in (I believe) 11gR2, there’s a new option starting with which can significantly decrease amount of data in the trace files for STAT lines compared to ALL_EXECUTIONS, still providing some of them from time to time.

Here is a case to demonstrate:

Parallel Parking – What is causing the Query to be Executed in Parallel?

July 31, 2012 I encountered an interesting OTN thread that caused me to stop and think for a couple of minutes.  The OP (original poster) in the OTN thread wondered why parallel execution was used for a query when the parallel degree for the table accessed by the query and its indexes were specified to have [...]

Presenting at UKOUG 2012…

I’ve got confirmation that I’m presenting at the UKOUG 2012 conference in December. As I’ve said before, I like seeing places, but I hate the travelling, so I’m not looking forward to having to get to the ICC in Birmingham. That’s one killer 4 mile journey I’m going to have to endure… :)

See you there!



Repairman Jack : By the Sword

By the Sword is the twelfth book in the Repairman Jack series by F. Paul Wilson.

Jack is hired to find a battered old Japanese sword. Unfortunately, there are some other people looking for it, including a group of Yakuza, a group of self-mutilating Japanese monks and people from a US religious cult. This is not going to be easy…

We are gradually getting closer to the end of times, so things are getting progressively chaotic and weird. Despite how ridiculous the plot sounds in a one-liner, it actually moves along quite well. As I’ve said before, I’ve become so desensitized to the dark nature of the books, I’m able to see past the grimness. I’m not sure if that should worry me or not…



Final Redgate Webinar

Thanks to all those that attended the last Webinar organised by James Murtagh (@allthingsoracle) of Red Gate Software. It was very well attended and the feedback was all pretty good although, as I've said before, ASH Analytics presentations always seem to go down well and I suspect that says as much about the feature as it does about the presenter, if not more! If you missed out and fancied checking it out, the video is available here. Interval Partitioning Constraint Creation Bug

A small problem that cropped up on a client site this week which might warrant a quick post to help any Google desperadoes that might find themselves in the same spot, not least because there's an easy workaround.

The existing application schema creation scripts used the following type of syntax to create Primary Key constraints and the underlying index in one shot against Interval Partitioned Tables. (Note, this is a simple test case I created for the Service Request that you should be able to try in other environments.)

Interesting blog notes

Just a pointer to two blog posts that I find worth mentioning:

1. Christo Kutrovsky from Pythian writes about some quirks he found regarding Parallel Distribution of aggregation and analytic functions. In particular the lower part of the post (which is not about the initial Interval Partitioning issue) gives a lot of food for thought how the chosen Parallel Distribution can influence the performance of operations

Fedora 17, Xfce and Cairo-Doc…

Followers of the blog will know I’ve been using Fedora as my main desktop/server OS for quite some time. I tend to use the default settings as much as possible, so that meant I switched to GNOME3 (when graphics cards allowed) and was generally not too displeased with it. I know a lot of people hate GNOME3, but I found it OK…

I think using XP at work has made me appreciate the simplicity of the old-style menus, so in a little fit of “I need a change”, I switched my window manager to Xfce. It’s quick and kinda basic as far as the interface goes, but feels really comfortable and familiar. So as not to get withdrawal symptoms from all things spangly, I’ve installed Cairo-Doc to get a posh little OSX-like doc at the bottom of my screen.

I’m not sure how long this new look will last, but so far I dig it.



Compression Units – 3

For those who have read the previous posting of how I engineered an Exadata disaster and want to reproduce it, here’s the script I used to generate the data.