The requested URL /pls/apex/f was not found on this server. - out of blue

Andrew,

1. Where do i see apex and page(s) logs?

There's a report on the user activity logs. Not sure what logs you mean though.

2. Where can i see the error(s) thrown by applications processes? ( basically smth that is not visible in "debug" messages" ?

No errors are thrown. In PL/SQL, exceptions are raised. If they are handled, you don't see them. If they aren't handled, sometimes the effect ripples up the call stack and you get the situation you are seeing. When application processes raise exceptions and you are running with the developer toolbar shown, this statement is issued:

htp.p('sqlerrm:'||sqlerrm);

...so you should see the result of that. Running the page in debug mode doesn't give you granular enough trace to be able to know exactly where a problem occurred, either with application processes or just during the normal rendering (show) or accept request. So the methodology I described (which you used) is the easiest way.

3. How can i debug the application processes?

What type of application processes? Those that run on every page view or those called on demand from ajax?

Scott

Andrew,

RE : 1 - For now i just want to be able to see step-by-step what is happening when rendering or submit has occurred.

Running in debug mode will show you that.

RE: 2 - you said :"So the methodology I described (which you used) is the easiest way." i'm not sure i understood - what methodology?

You said in the second post in this thread, "the approach i used to nail down the region is link: here", and you linked to a post where I described how I would do it, shown again here:

I would systematically disable everything on the "show" side of the page. Start with regions. Put a Never condition on each. Run the page. If the error stops, you know the problem was in one of the regions. If not, disable processes and computations, etc. Then enable these components one at a time until the problem recurs. When you isolate the problem region (if it is a region), then disable items and buttons in the region and so forth. The problem may be due to an unhandled exception somewhere inside one of the components.

RE: 3 - any type. It's not clear ( for me at least ) if the binding occurs correctly, what values get passed to the pl/sql . Did i refer to the session variable correctly or i made a typeoff, etc, etc;

Again, more specifics about the situation would help. When the page debug output is not sufficient, and instrumenting your own code isn't enought, you can always trace your database session and see what happened. Add &p_trace=YES to the URL, run the page and/or submit the page and then check the database dump destination for the trace file and use tkprof to get a report.

Scott