Jonathan Lewis's picture


No, not active session history – but the volcanic stuff that’s drifting through the skies and keeping me in Denmark after Miracle Open World 2010. I’m feeling a little lucky at present (compared to the other visiting speakers – especially the American contingent). My flight home on Friday was postponed then cancelled, but my diary [...]

Jonathan Lewis's picture

Predicate (again)

I often make a fuss about making sure that people include the predicate section when looking at execution plans. Here’s another example demonstrating why it can be so helpful. We start with an SQL statement that happens to have a large number of child cursors – and every child cursor has exactly the same plan_hash_value [...]

Jonathan Lewis's picture

Analysing Statspack 12

[Back to part 11] Part 12 is about a 2-node RAC system.  Someone recently posted links to a matched pair of AWR reports in this thread on the OTN Database General forum and, after I had made a couple of quick comments on them, gave me permission to use them on my blog. Because OTN [...]

Jonathan Lewis's picture

Call for Papers

The call for papers  for the  Tech Server and E-Business event in the UKOUG Conference Series is only a couple of weeks from closing, so I’m just bouncing this email to the top of the pile: Once again we are launching call for papers for the annual Technology & E-Business Suite user group conference. This [...]

UKOUG 2010 CFP is now open!

Can you believe it? Already?? Yes, that’s right, the Call for Papers for the UKOUG Technology and E-Business Suite conference is already open! In my opinion, this is one of the best conferences out there! Wide variety of speakers, great topics, and, it’s not too big! This coming year will be my fifth (or is it sixth?) year attending, and it’s a trip I’ve always enjoyed, and never regretted taking the time (or money) to attend.

The CFP is open through Monday, August 2nd, 2010. The conference itself is coming up on November 29th – December 1st, 2010, in Birmingham, England.

More information is available here.

karlarao's picture

My Personal Wiki – karlarao.tiddlyspot.com

Our brain does not work in a linear or list-like manner (yeah.. not like the guy on the right). From the textbooks and blogs that we read everyday we are all aware that print is laid out in a series of lines or rows…

but our brain is multidimensional…

the information as it is being absorbed could be travelling sequentially to our brain, but internally it is not being serviced in simple lists and lines. There is a complex process of sorting and selecting and the whole network of words and ideas are being juggled and interlinked in order to have a far better meaning.

Unintended Consequences

Hi all,

My apologies for my extended absence.  Well, I ran into something interesting today, and, I thought it would be appropriate for a blog post, and apparently, I got inspired.  No startling revelation here, this is just a bit of a cautionary tale about the unintended consequences of using a new feature.  A quick search of the Oracle Documentation confirms that the skip locked directive of the select for update statement was introduced in Oracle 11g, version 11.1. But, before we dive into that, let’s review the functionality of select for update through versions of Oracle preceding 11g.

Select for update

Jonathan Lewis's picture

Analyze this

Here’s a little script I wrote a few years ago to make a point about using the dbms_stats package. I’ve just re-run it on to see if it still behaves the way it used to – and it does. If you want to be just a little bit baffled, set up a database with [...]

Jonathan Lewis's picture

Philosophy – 9

There is an old joke about an engineer, a mathematician, and a philosopher sitting together in a train travelling from London (England) to Cardiff (Wales) ***
As the train crosses the border, the engineer glances out of the window and exclaims: “Oh, look! Welsh sheep are black”.
The mathematician responds: “No; all you can say is that [...]

Niall Litchfield's picture

Words fail me

I just stumbled across this fine example of the art of writing news articles when you clearly don’t understand the subject. The article has a date of 2 days ago on the front page, though curiously a September 2009 date on the article. The article purports to discuss the omotion feature of Oracle Rac One-Node. My [...]

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