Tuesday, October 07, 2008

OOW2008 Afterthoughts


As Oracle Open World 2008 is 1,5 week behind us, it is about time to finish up my posts on this subject - and get rid of my notes. So let's take a quick look on the sessions I didn't mention already.


Forms2APEX Migration
David Peake introduced the "soon-to-come" APEX 3.2 release. The most important new feature (or maybe the only new feature) is the support for migrating Oracle Forms to APEX. He emphasized that there is no need from an Oracle support perspective to move from Forms to APEX. You should only go for this route if there is a sufficient business justification for it. A migration from Forms to APEX has to be considered as a real project, consisting of Analysis, Design, Convert, Post Migration, Acceptance and Training. The Forms2APEX toolkit is in no way a silver bullet. There will be a lot of handcraft involved to achieve acceptable results. Especially for more complex Forms you'll need a lot of effort to get similar functionality in APEX. Luckily the tool helps you to identify non converted code. Coming to a theatre near you at the end of 2009....

Inside the Oracle 11g Optimizer: Removing the mystery
A session somewhat out of the APEX scope, but nevertheless very interesting. The highlights of the new 11g optimizer stuff are:
  1. Full control over the execution plans, using SQL Plan Management (SPM). Using SPM, a change in an execution plan has to verified before it is actually used.
  2. Extended Optimizer Statistics to collect statistics over a group of columns.
  3. Improved Statistics Collection :
    1. AUTO_SAMPLE_SIZE - With the speed of 'estimate' (or even faster) you can get the quality of 'compute'.
    2. Incremental Global Statics for partitioned tables: global statistics are built from the partition statistics.
  4. Adaptive Cursor Sharing & Enhanced Bind Peeking: In version 10g and before an execution plan was determined by the initial value of a bind variable and the same execution plan is shared regardless the subsequent bind variables. But a select on emp 'where job=VP' returns only one row and will probably benefit of using an index on job. But if a select on emp 'where job=WORKER' returns 90% of the rows, the same execution plan is used. Starting from 11gR1 the same query can have more execution plans depending on the values of the bind variables. With Adaptive Cursor Sharing plans are shared when bind values are (more or less) the same and a new plan is generated when the binds are not equivalent.
Tom Kyte's Sessions
Tom Kyte did a number of sessions that week and I visited two. In one of the sessions - the Oracle Develop keynote - Tom did a great ad for APEX. He called APEX the best Oracle tool around, next to SQL Developer and SQL Plus!
Tom told the audience about his experience on the questions raised on the asktom-site. He gets a lot of questions regarding the tuning of queries. Most of the time the response is "Why would you do that?". So often it is better not to tune the query, but tune the question (or the process)!
In his session about managing change Tom announced that the long awaited Online Application Upgrade will be part of 11gR2 (ofcourse with the regular disclaimers). Oracle showed this impressive feature already at OOW in 2006 (see my post about that here), and it will finally make it into the next release of 11g!

The power of the APEX Repository
Patrick Wolf did an impressive presentation - with beautiful pictures ànd sound - on the repository. You can use the repository not only to store the APEX-metadata, but you can use the data inside also for quality checks, documentation, sitemaps, application page flow, generic code, monitoring and modification - using an export file or (more dangerous) directly in the tables.

Building large commercial applications with APEX
The guys from PAETEC impressed the audience with their presentation on the APEX version of Pinnacle, their tool for Service Life Cycle Management. It is a large application consisting of around 800 tables and 2000 pages in 19 applications. They build it in 2 years with 20 developers. So who dares to say APEX is only for Excel or Access replacement?
They extensively use the APEX repository to generate information on the pages and did some advanced tweaking by modifying the arrays used for rendering, just before the page is painted. Using their own framework they emphasized the separation of layers: Presentation with no validation at all, business rules using views and triggers and the data. So a three tier model, but with all tiers in the database!

Building a Web 2.0 interface with APEX
Marc Lancaster had the questionable honour to do the last APEX presentation of this OOW. He explained the advantages of Javascript, AJAX, JSON and external libraries. He is using ExtJS extensively on his demo site. To summarize:
• Takeaways
– AJAX doesn't have to use XML, or be asynchronous
– Javascript performance is rapidly improving
– Consider Namespacing when integrating Javascript libraries.
• Key concepts
– Start learning and using AJAX and JSON
– Progressively add functionality through templates
– Look for low hanging fruit
– Javascript libraries can do the heavy lifting
– Apex will us jQuery in version 4.0.
• Lessons learned
– Factor in time to build templates
– Always consider page loading performance.



Wrap up

To conclude, this year's OOW was again a huge event, and with lots of opportunities to attend good sessions, meet old friends and create new friends. Thanks to all who made this a unforgettable week!
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