29 August 2011

PL/SQL Challenge upgrades to APEX 4.1

We upgraded the website to APEX 4.1 over the weekend. Overall, it went smoothly (thanks, John Scott of Apex Evangelists!). We had to upgrade some plug-ins, but that was easy enough.

Two issues have caught our attention, though:

1. It seems as though processing on the website has gotten noticeably slower in a few spots (I click on the Play Now button and wait 5-10 seconds to move to the quiz page (don't worry - this time is not recorded as part of your answer time!). Does anyone else see this happening?

2. URLs with checksums generated by apex_util.prepare_url no longer seem to work; that is, even though the URLs include a checksum, you see this error:

Session state protection violation: This may be caused by manual alteration of a URL containing a checksum or by using a link with an incorrect or missing checksum. 

The behavior on Firefox seems to be inconsistent. On Internet Explorer, though, the URLs are always failing and we just noticed that IE seems to be changingthe URL. That is, I paste in this URL into Firefox and it works fine:


I then  paste it into IE8 and press enter, IE8 changes the url to:


Notice that & is changed to %26. And then I see the checksum error.

Do you have any experience with this?

Cheers, Steven Feuerstein


  1. Hello Steven,
    This 5-10 seconds issue is probably unrelated to the slow response time that I complained about during the last week ... since the upgrade happened afterwards.

    However, how is it possible that these 5-10 seconds DO NOT count as part of the answer time,
    while the MUCH LONGER waits experienced previously DID, unfortunately, COUNT :( :( :( ?

    Is there a mechanism by which you can control and identify the PRECISE MOMENT when a page is displayed ? If yes, then any slowness issue could be considered as solved ... or I am wrong in my understanding ...

    Thanks & Best Regards,

  2. So far as I can tell, and have been told by people with much more experience than me, there is no way to determine (in APEX) the precise moment when all images have been displayed to you.

    We have already moved the procedure call that indicates you have started the quiz to the bottom of all load processing on that page.

  3. Great news! The APEX dev team confirmed this as a bug and supplied a patch...TODAY...so the links should now be working.

    What a great group of developers!

  4. Hello Steven,

    I expect soon to hear the same praises about the PL/SQL product group of developers ...

    If they also were that eager in correcting compiler bugs, then we would not have any more quizzes like the one of Aug 29 ... and a few several ones ... and life would be more beautiful :) :) :)

    Maybe the more than "2 penny" contribution of our PL/SQL Challenge community will ultimately aid in improving the product ... let it be even just for leaving something behind us ...

    By the way, APEX looks interesting for me, as one that is not experienced with it ... may I dare to say "yet" ? ...
    Wishful thinking ... but this is very hard when you are isolated, without "a proper itinerary and environment" for such an attempt ... though it's a pity that no one thinks of leveraging the vast Oracle Forms experience that probably many older Oracle developers do posses ...

    Best Regards,