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Server-Task delaying

Hi,

some of my task-chains which runs daily triggered through the qv server (no publisher available) needs to be to delayed on sunday for 5 hours.

For this I have created some start-qvw's which check the weekday and delay it then - the weekday checking worked without a problem but the delaying from following-tasks is only 60 minutes (3 task-chaines) or 90 minutes (2 task-chaines).

Are there any timeout-settings or could it be that there are then too many parallel-tasks (how many are possible within the server - two?) because of this waiting some of the task-chains are now overlapping eachother?

How could it be handled? Especially if I don't want to use solely windows-task triggered macro-routines (which I have used previously).

This is the routine - but I think they isn't the issue:

if num(weekday(today())) = 6 then

    // hours * minutes * seconds * 1000 (for milliseconds)

     sleep 5 * 60 * 60 * 1000; // 5 hours delay on sundays (values in milliseconds)

else

    sleep 50;

end if

I hope someone could help me. Many thanks.

- Marcus

1 Solution

Accepted Solutions

Re: Server-Task delaying

Hi Marcus,

I temporarily switched over from the bbq to a portable qlikview server (someone else is doing the dishes ) to bring you some good news: yes, there is a setting to improve your situation, but it is hidden in a configuration file and the QMC won't be of any help.

Open C:\Program Files\QlikView\Distribution Service\QVDistributionService.exe.config. Notepad will do just fine, but you can use any text editor.

Scroll down until you encouter a setting called "QvbWaitTimeoutMinutes". Overthere you'll find your value of 45 minutes. Increase this value so that it takes the maximum delay into account: the 5-hour wait time+the actual reload delay+any margin that you think is suitable.

Save and restart the QDS.

Note that this is a global setting. From now on, all queued tasks will wait for a free QVB engine for a very long time before giving up.

Alternatives? As far as I can see you are fighting a limitation of the standard Publisher "built into" QlikView Server: every task has only one trigger with a single set of specifications and those turn out not to be very flexible at all. Possible solutions:

  • Buy a Publisher license (too obvious and probably not very helpful...) With a full Publisher, you can give a task any number of triggers with any type of settings. For example running a task at a fixed time 6 days every week, and at another time on sunday only.
  • Or set your reload tasks to be triggered by "an external event", and use Windows Task Scheduler in combination withQMSEDX Enhanced to trigger a single task at different times every other day. More complex but very flexible.

Best,

Peter

15 Replies

Re: Server-Task delaying

Anyone has an idea or a hint for me?

- Marcus

Re: Server-Task delaying

Are your delay QVWs being aborted? Or do they run the full delay that you specified in the Timeout input field on the reload tab? Note that this Timeout value includes everything: all retries and all task setup/shutdown delays.

Re: Server-Task delaying

Sorry Marcus, ignore my previous post.

Better check the QV Help article on statement SLEEP. The very first sentence will be very enlightening...

You can fix this problem by embedding a SLEEP statement in a FOR loop.

Peter

Re: Server-Task delaying

Many thanks, this is definitely a point and I will try it with such a for-loop!

Do you know how many tasks the server could parallel execute even they are in waiting-loop? I think I have read somewhere that there are limitations at least by the server (or even by publisher?).

- Marcus

Re: Server-Task delaying

Yes there are limits to the number of parallel reload jobs you can have running (you can start many more but they will be queued). The limit can be modified. Best practice is to not set this number to anything higher than the number of cores in your server minus one. Reloads (especially JOINs) may cause a core to go to 100% load, and you don't want all cores to be in this state as Windows will become unresponsive (the reloads will succeed though )

See QMC->System->Setup->QlikView Servers->your servername->Performance->Reload limits.

Re: Server-Task delaying

How does this queueing work? Will they be executed considering to their start-time and after the first few task-chaines are finished the next one within the queue started although is origin start-time was already for hours or will they be skipped?

- Marcus

Re: Server-Task delaying

Yes indeed. If you have two cores available for reloads, and four tasks should start at the same time, two of them will be delayed until Reload engines become available. As one of the first two reload tasks is completed, the reload engine will be freed up and the next task will allocate it for script execution. As far as I know, the mechanism is first-come, first-served-based.

The funny thing is that the 4 tasks-2 cores setup will show 4 green play buttons in the QMC Status screen, so that you know that 4 tasks are due to be completed. But only 2 of them are actually running simultaneously.

Best,

Peter

Re: Server-Task delaying

Many thanks - then it should work only with the measure that I applied the for-loop to extend the max. sleep-time. I see then hopefully the next Sunday against ...

- Marcus

Re: Server-Task delaying

Good luck

Peter