December 2011

I have been lucky enough to do some work with Fusion IO cards in a blade server, soon to be followed by another set of tests on a full rack mounted server. I didn’t know exactly where model I was given, but powered my server down in eager anticipation of the events to come.

After the engineer plugged the card in, and powered the server up I logged in as root to find out what about the pre-christmas present. I knew it was a PCI card, so surely lspci would tell me more. Here’s the output:

The UKOUG Technology conference in Birmingham was yet another great showcase of Oracle knowledge sharing and networking. The weather was surprisingly good for that time of year in Birmingham, though, the conference kept me so busy that I rarely had a chance to walk the streets. I had the opportunity to hear a presentation by and then speak with Bryn Llewellyn from Oracle; I’ve subsequently improved (I hope) my paper on Edition Based Redefinition; I’ll be presenting a new and improved version at Collaborate in Las Vegas this spring. Another highlight was watching a team of Oracle Middleware experts from Holland work to create a replacement conference registration system in a four-hour session using Oracle SOA, BPEL, ADF, and other middleware tools. What a demonstration of flexibility and capability!

Challenges and Chances of the 11g Query Optimizer is the name of a presentation I gave at several events (e.g. Trivadis Performance Days, Oracle OpenWorld, DOAG Konferenz, UKOUG Conference) throughout 2011. Its abstract is the following:

With every new release, the query optimizer is enhanced. Oracle Database 11g Release 1 and Release 2 are no exception to the rule. Specifically, they introduce key improvements in the following areas: indexing, optimization techniques, object statistics and plan stability. The aim of this presentation is to review the new features from a practical point of view as well as to point out challenges related to them. In other words, to let you know what you can expect from the query optimizer when you upgrade to Oracle Database 11g.

In a recent question on OTN someone asked why Oracle had put some columns into the overflow segment of an IOT when they had specified that they should be in the main index section (the “IOT_TOP”) by using the including clause.

The answer is simple and devious; there’s a little trap hidden in the including clause. It tells Oracle which columns to include, but it gets applied only after Oracle has re-arranged the column ordering (internally) to put the primary key columns first. The OP had put the last column of the primary key AFTER the dozen columns in the table that he wanted in the index section, but Oracle moved that column to the fifth position in the internal table definition, so didn’t include the desired 10 extra columns.