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November 2011

Headlong rush to Conference – Preparing the Presentations

With only a few days to go before the UKOUG conference this year I’m preparing my presentations. I know pretty much what I want to say and, for the IOT talk at least, it is not as if I do not have enough material already prepared – some of which has been on the blog posts and some of which has not. (though it did strike me that I could just fire up the blog and walk through the thread, taking questions).

My big problem is not what to say – it is what not to say.

Mike Carey: Thicker Than Water…

“Thicker Than Water” is book 4 in the Felix Castor series by Mike Carey.

I’m not even going to try and summarize this bad-boy. It’s just a crazy-paced page turner. We find out more about Felix’s life before he became a freelance exorcist. More about his brother, the Catholic Priest. More about the Anathemata, the excommunicated millitant arm of the Catholic Church. Juliet, the succubus, gets involved in the action again. It’s just bam, bam, bam. Love it. :)




I missed my fifth blogging anniversary by a month – my first post was dated 24th Oct 2006 on the topic of the parameter optimizer_index_cost_adj.

Since then I’ve posted about 670 articles (and deleted a few temporary ones) and drafted another 110; I’ve acquired 750 followers;  and the blog has inspired a little  over 6,000 comments. It’s amazing how time passes and the numbers accumulate.

To celebrate the event I’ve created a new category (see top right) of “Site History” so that I could label that first post and the various posts I’ve made about viewing figures and popular posts.

Recycle bin

Recent Charles Hooper’s post on the topic of Recycle bin (which is, BTW, documented behavior) reminded me of an issue with that functionality I’ve seen recently. The problem was a single-row INSERT INTO table VALUES () statement was hanging for more than an hour burning CPU.

BIN$ Index Found in the Execution Plan – Digging through the Recycle Bin

November 28, 2011 There are a few articles that can be found on the Internet that describe the cause of indexes with names similar to BIN$ld5VAtb88PngQAB/AQF8hg==$0 and BIN$PESygWW5R0WhbOaDugxqwQ==$0 appearing in execution plans.  As is likely known by readers, the Oracle Database documentation describes that these object names are associated with the recycle bin that was introduced in Oracle Database [...]

Oracle Core

28th November 2011

I’ve just received an email telling me that Apress is having a “Happy Cyber Monday”. Translated into English this means that for today only they’re selling every eBook at  $15.00 each. If you were planning to get an eBook version of Oracle Core, today might be the best day to do it. Here’s a link to the specific page on the Apress site. I’ve repeated this link in the picture of the book at the top-right of this page.

If you want the paper copy, it started shipping from Amazon in the US quite recently but isn’t yet shipping from Amazon UK.

Making Simple Performance Charts

Before I dive into this blog post, quick heads up for anyone attending UKOUG: on Tuesday only, I’ll be hanging out with some very smart people from the IOUG RAC Special Interest Group in the “gallery” above the exhibition hall. We’re ready to help anyone run a RAC cluster in a virtual environment on their own laptop. And if your laptop doesn’t meet the minimum requirements then you can try with one of our demo workstations. Come find us!!

Why Make Charts

I’ve heard Kyle Hailey speak on a few different occasions, and more than once he’s talked about the power of visualizing data. (In fact Kyle was a key person behind Grid Control’s performance screens.)

Is 61.11% Fragmentation Too Fragmented For An XFS File System? No!

Thought of the day:

An XFS file system with 98% free space, 6 files and 61.11% fragmentation:

# df -h .
 Filesystem Size Used Avail Use% Mounted on
 /dev/sdb1 100G 1.1G 99G 2% /test
 # find . -type f -print | wc -l
 # xfs_db -r -c frag /dev/sdb1
 actual 18, ideal 7, fragmentation factor 61.11%

When I asked about this oddity in a conversation with Dave Chinner (XFS Kernel owner) I was expecting a lot of complex background on what this 61.11% actually means. His response? I’ll quote:

18 – 7 / 18 = 0.6111111

[…]it’s been that way forever. Ignore it – it’s much more important to look at the files themselves […]

IOT Answer

It was good to see the answers to the last Quiz Night accumulating. The problem posed was simply this: I have two IOTs and I’ve inserted the same data into them with the same “insert as select” statement. Can you explain the cost of a particular query (and it’s the same for both tables) and extreme differences in work actually done. Here’s the query, the critical stats on the primary key indexes, the shared plan, and the critical execution statistic for running the plan.

S-ASH 2.3 available


“New features:
- new easier installation process
- new metrics history (IO and system)
- improved support for RAC / multi database in one repository
- Oracle scheduler is used to manage jobs

This version of OraSASH has been tested with Oracle 10g and 11g R1 and R2 as a target database and Oracle 11gR2 Express Edition as repository.