Thursday, May 7, 2015

Wednesday, March 25, 2015

Oracle APEX - Performance tuning sequences


I've been recently reading about performance issues for sequences with cache values set too low.

  • Daniel Morgan www.morganslibrary.org, covers it in his ACE Director Performance Tuning Bootcamp presentation
  • Tom Kyte says "you would be amazed what setting a sequence cache via alter sequence to 100,000 or more can do during a large load -- amazed."
  • Simon Pane from Pythian goes into great detail in a blog post performance issues with the sequence nextval call. He also show to detect when sequences are impacting performance.

With APEX 5.0 nearing general release, I thought it would be interesting to see what the cache value was set to for WWV_SEQ. In case you don't recognize the sequence, it's used by the APEX engine as part of a calculation to generate globally unique ids for APEX items.

A quick check on apex.oracle.com reveals the APEX team have been thinking about it also:

select sequence_owner, cache_size, last_number
  from all_sequences
 where sequence_name = 'WWV_SEQ';

SEQUENCE_OWNERCACHE_SIZELAST_NUMBER
APEX_0500001006939179
APEX_04020020719290506

Interesting to see the cache size was set to the default value of 20 in APEX 4.2 and is now set to 100 in APEX 5.0. That's the "sweet spot" identified in Simon Panes blog also.

So, if you have an active Oracle APEX 4.2 instance, it may be worthwhile investigating..

Monday, February 2, 2015

APEX 5 EA 3 - Universal theme

Oracle APEX 5 early adopter 3 just came out.

I've been taking the Universal Theme Sample Application for a quick test drive.


I'm truly impressed by what I've seen so far, and a little sad at the same time..

Oracle APEX developers typically come from a database development background, so have strong database design and PL/SQL skills, with relatively few of them having strong web design skills.

In some respects, this has held back the adoption of Oracle APEX in organisations. Developers have been able to quickly build useful and functional web applications using the provided themes with relative ease.

Functional Lada
Sexy Veyron Super Sport
Trouble is "functional" websites don't evoke the same emotional experience as a "sexy" website, just like a functional car like a Lada doesn't evoke the excitement and desire of a super car like a Veyron (pinched from Joel Kallmans' blog).

Out there in "user-land" functional and practical websites don't engage our customers in the same way a visually appealing and well thought out interface does. The visual appeal of any website plays a vital role in user satisfaction. A visually appealing website give the user a positive first impression, and builds the desire to work with it.

Now thanks to the Universal Theme, having a "sexy" website is within the reach of every APEX developer. It looks fantastic out of the box, chock full of the latest UI components and highly configurable with little or no knowledge of CSS. With Oracle APEX 5.0 everyone can build web applications that are both functional and sexy.

To the APEX development team, I tip my hat to you and say very well done.

So why do I feel a little sad; it's always been a fun putting together a great UI for an application to transform it from functional to appealing. I won't get to do that so much now, it looks great already.