Chuck,

On 25. 2. 2015, at 18:18, Chuck Hill <[email protected]> wrote:

> I just thought of something else.  Is this app running with a single instance?

Yes, it is.

> If so, this might mean that the response was no received from the app before 
> the Receive Timeout expired  (see Adaptor Settings in on the application page 
> in Java Monitor).

Can it lead to this weird report? I always thought it leads to "No instance" 
pretty consistently. At least, it did when my app was really slow, before I 
moved the imports to a background task :)

> The solution to that is to make your app faster :-) or increase the timeout.

Anyway, App.awake to App.sleep the request took 9.952 seconds -- it is a lot, 
but it should be safely below the default 30 s (and if the server admin changed 
that, he would hardly decrease the default).

> Is this app running without concurrent request dispatch enabled?

Nope, it runs with concurrent dispatch enabled (which causes lot of grief by 
itself, for 70-odd per cent of the codebase is years old and has been written 
for serialized requests... but that's another story).

> ... That also explains why the app log does not correspond to the user’s 
> perception.

Most time, it does.

Far as I can say, yesterday was the first time this happened (some cases might 
well be unreported of course).

> It sounds like either the CSV import is doing too much before handing off to 
> the second stack, the second stack is not getting used correctly (I doubt, 
> but will mention), or some other action in the app is slow.  If there is a 
> lot of constant database access (like a big save or big fetch) from one 
> request, it will cause other requests (using the same OSC) to queue up for 
> the EOF lock.

That was the problem we hopefully cured lately in the thread “looong 
saveChanges in a background task”; but it did not happen at the moment -- far 
as I can say. (Well at least I still do log all the DB operations, and none 
were logged there.)

Thanks again,
OC

> On 2015-02-25, 8:57 AM, "OC" wrote:
> 
> Oh, and since I'm writing anyway...
> 
> On 24. 2. 2015, at 18:48, Chuck Hill <[email protected]> wrote:
> 
> I don’t see that one very often.  IIRC, it means that it sent the request to 
> an instance and got a null response back.  That probably means the app threw 
> an exception either very early or very late in the R-R loop.
> 
> Thanks!
> 
> Check the app logs for exceptions.
> 
> None. Far as I can say, the request -- it was CSV import, too, but none of 
> those which went wrong -- did spawn its background thread and finished all 
> right -- I'm logging R/Rs from application's awake/sleep, and all looks OK. 
> Definitely no exception in my application log nearby.
> 
> Did an instance run out of memory?
> 
> Hardly. I log the heap (and lately also the Perm Gen stuff which bit my back 
> a couple of days ago), and there was plenty of both.
> 
> Check the Apache error.log just to be sure.
> 
> Thanks again, I've asked the system admin to do that. I did that anyway, for 
> that day there _was_ something fishy (hmmmm... perhaps it even might be 
> related):
> 
> The thing is, I've got a report from a user that one request took more than 
> 20 seconds to reload in his browser. I have found it in my logs, and 
> App.awake to App.sleep it took 1.818 seconds. Another request reported to 
> last a dozen of seconds from the user's point of view took 0.577 seconds 
> App.awake to App.sleep. Weird.
> 
> Thanks again,
> OC
> 
> On 2015-02-24, 8:35 AM, "OC" wrote:
> Hello there,
> what the $subject means and who reports it?
> I've googled a bit before coming here, and found
> (a) it seems to be a Wonder error report 
> (https://github.com/wocommunity/wonder/blob/master/Utilities/Adaptors/Adaptor/errors.h)
> (b) it seems to be quite common to see with Apple own applications 
> (http://forums.appleinsider.com/t/418/apple-store-seems-to-be-down-right-now/40
>  and more similar ones, with Knowlegde Base, with Apple WebMail, etc.)
> (Incidentally, Apple uses Wonder? That's nice to know.)
> But what I haven't been able to find (yet) is what it actually means? :-O I 
> did succeed to find the appopriate source (transaction.c in the Adaptor) and 
> function (_errorResponse) which seem to generate the report, but without a 
> detailed study of the adaptor code I'm none the smarter of what condition 
> causes this (well, the condition is that WOAppReq.error contains 4, but... :))
> Does somebody here know, or am I to dive into the adaptor sources?
> Not that I would care, but one of the users of my application did see the 
> thing today :(
> Thanks a lot,
> OC
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