Comments on: RMOUG Debrief

By: Jonathan Lewis

Jonathan Lewis — Mon, 12 Mar 2012 14:05:51 +0000

Lasse,

The course was only 3 days – though it may have felt like 5 given the volume and quality of information. The supporting notes from that course totalled about 400 pages, with about 100 SQL scripts. I had to stop presenting it eventually because Oracle was releasing upgrades and patches faster than I could keep the notes up to date.

Raghav,
If you’re in the USA, I’m scheduled to do the same three presentations at ODTUG in San Antonio on 24th – 26th June.
Alternatively, I’ll be doing one of my full day tutorials that covers the material in Minneapolis and Salt Lake City in mid May, and in Dallas at the end of June.

By: Jason Bucata

Jason Bucata — Mon, 20 Feb 2012 19:04:32 +0000

Nice to finally talk briefly with you in person!

By: Todor Botev

Todor Botev — Mon, 20 Feb 2012 10:11:43 +0000

Jonathan,

These are real comments from our code:

Special optimizing of the HASH JOIN. The big hash join caused too big TEMP space consumption…..Join ONLY ROWID to avoid joining all the large columns. More on this method here: http://jonathanlewis.wordpress.com/2008/05/09/manual-optimisation-2/

XML will be generated directly with the Select itself. The old way (appending the rows and columns one after another) prooved to be very slow because of the numerous concatenations of CLOB with strings. See here for further explanation of why it was slow: http://jonathanlewis.wordpress.com/2009/07/09/concatenating-lobs/

And there are other solutions inspired by you, not explicitely commented:

- The NO_MERGE hint solved us numerous problems by complex view merging. I can count more than 70 usages of the hint.

- The NO_UNNEST hint saved our lifes in a specific situation with subqueries.

- Why is the PARTITION EXCHANGE full scaning the tables – even when *whithout validation* is specified? There is an old but very usefull article by vou on how partition exchange is dealing with constraints – which opened my eyes on the subject.

I will stop here because the post got rather long – and these are all things which I just thought of the top of my head.

By: Lasse Jenssen

Lasse Jenssen — Sat, 18 Feb 2012 10:43:11 +0000

Exactly Raghav. That was aslo my first thought. Then I started to think about it. Jonathan just released his new book “Oracle Core”. He must have shared some of those “secrets” inside this new book :-) I allready got the book, now I just have to keep reading. By the way … this is an excellent book. Very understandable and easy to read. I attended a 5 day class with Jonathan in Bergen, Norway about 4-6 years ago. The compendium from back then started to get really worn out. It was about time that this book was released :-). Jonathan: Are you still giving those 5 day classes?

By: Raghav

Raghav — Fri, 17 Feb 2012 22:36:45 +0000

Hi Jonathan,
Thats really awesome. Where can we find the slides :)