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March 2012

Oracle Linux 5.8 and UDEV issues…

I just did an update from Oracle Linux 5.7 to 5.8 on one of my VirtualBox RAC installations and things are not looking to clever at the moment. After a reboot, the ASM instances and therefore the database instances wouldn’t restart. A quick look showed the ASM disks were not visible. On this installation I was using UDEV, rather than ASMLib. In checking the UDEV rules I noticed the scsi_id command on OL5.8 doesn’t report an ID for partitions on disks, only the disks themselves. For example, on OL5.7 I get this,

# /sbin/scsi_id -g -u -s /block/sdb/sdb1

On OL5.8 I get this,

# /sbin/scsi_id -g -u -s /block/sdb/sdb1

If I run it against the disk, rather than the partition it works fine.

Quick SQLDeveloper Hint — Dial0gInput

The other day I was attempting to debug a SQL statement which was doing a REGEXP_REPLACE and the comments said something like “remove all zero’s from the string”.

However, in looking at the code, it looked like it was removing all capital O’s from the string instead of 0′s — see even here within WordPress I can’t tell the difference between an O (the letter) and a 0 (the number).

At first I thought it a coding mistake until I tried to type both of them into a window within SQL Developer — nope, they looked the same. Must be a font issue.

Fonts can be changed in SQL Developer under the Preferences / Code Editor / Fonts selection — you may want to limit choices to fixed-width fonts by checking “Display Only Fixed-Width Fonts”. The default on my system was DialogInput — which appears to have the O/0 problem. I ended up choosing Consolas 12pt and exiting back out to the editor.

Only to see a horribly grainy looking font.  Yuck!

AIM SIG and my talk about Enterprise Manager 12c

Yesterday I presented at UKOUG’s Availability, Infrastructure and Management Special Interest Group (hey, say this 3 times in a row, quickly!) about Oracle Enterprise Manager 12c and my experience with it. As my good fried Piet de Visser pointed out I had way too much to say for the 45 minute slot allocated. But then Piet always tells me that. Sadly he is also often right :) That’s why I like seeing him during my talks!

In summary I would have liked to do a different presentation, and that’s for two reasons: 1) I overran and 2) I haven’t managed to show the patching part which is hugely interesting, at least to me.

Now here’s the reason for the blog post. I haven’t done online seminars yet, and was wondering if people were interested in a 1-1.5 hour UKOUG-like presentation from myself, broadcast via Goto Meeting or similar to an audience. Would that be of interest? The topics to be covered are:

Just a short note that as already announced last week the second part of the post on how to control Dynamic Sampling activity has been published on

You can read there about the (not so much known) DYNAMIC_SAMPLING_EST_CDN hint, the new Dynamic Sampling auto adjustment feature introduced in release 11.2 and other interesting details.

Displaying SQL Baseline Plans

Since I’m on vacation and not “really” working, I thought I might have time to write up a quick blog post. The idea for this one was triggered by one of Maria Colgan’s presentations at Hotsos last week. Maria was talking about SQL Plan Management and Baselines and somehow got me thinking about the DBMS_XPLAN option to display plans for Baselines. This is a pretty neat feature that allows you to the see the plan associated with a Baseline (well sort of).

The 11.2 documentation (Oracle® Database PL/SQL Packages and Types Reference) says this about the DISPLAY_SQL_PLAN_BASELINE function:

Hyper-Extended Oracle Performance Monitor 6.0 Beta

March 15, 2012 (Modified March 16, 2012) Several people expressed an interest in using the Beta version of my Hyper-Extended Oracle Performance Monitor 6.0 that has been under development for about a decade.  Rather than trying to find a way to deliver the Beta version of the program to those people who left comments in [...]


The column is there for a long time – even 9i documentation have it. I’ve never thought about it until today when I caought something extraordinary on instance.

Starting with 10g oracle introduced SQL_ID for simplicity; it is used in combination with CHILD_NUMBER to locate a particular row in the V$SQL. The documentation is clear (bold is mine):

V$SQL lists statistics on shared SQL areas without the GROUP BY clause and contains one row for each child of the original SQL text entered

OpenWorld 2012 Call for papers...

The call for papers for Oracle OpenWorld is now open.  Give it a try and see if you can get a slot!

Oracle ACE Directors + 1 — Gwen Shapira

Quick post congratulating Gwen Shapira on becoming Oracle ACE Director. Gwen has be an Oracle ACE for a while by now and been very active in the community. Widely recognized in the conferencing circles and a frequent blogger, Gwen has recently been focusing a lot on Big Data and many of her recent articles have [...]

What's important

In reviewing my blog activity over the past few years, I noticed that the first two years I had the blog I averaged about one post per week. The next year, my posts fell off to about one per month. Then last year, I only had 3 posts! Talk about decline!