topic Tricks for scheduling dependent tasks in QlikView

Tricks for scheduling dependent tasks

rwunderlich — Mon, 26 Jan 2026 18:19:17 GMT

I'm looking for tips on scheduling large dependent task chains. In QVP 8.5, we had document sets which handled the problem nicely. But document sets are not available in V9.

Here's the scenario. I have a group of 20 QVD reloads that need to execute first followed by the application reloads. The application reloads should not start unitil all QVD reloads are completed. The only way I can ensure all QVD reloads are complete is to run them serially and chain the application reloads off the last QVD.

What I would like to do is run the QVDs in parallel and start the applications when all QVDs are complete. Any ideas on how to do this wihtout just having a single task chain for all QVDs?

I''m facing this problem on both SBE edition and Publisher Enterprise.

Thanks,
-Rob

Tricks for scheduling dependent tasks

Tue, 27 Jul 2010 08:15:06 GMT

Hi Rob,

What about having a dependency on the QVW reload, that only start on success of the QVD reloads ?

Tricks for scheduling dependent tasks

vgutkovsky — Sat, 31 Jul 2010 00:39:36 GMT

Hi, Rob. Really interesting question. I'm not 100% sure, just throwing some ideas out there. Assuming you have a server with enough cores and memory, you can schedule up to 10 QVBs at the same time. So you could have the following structure: (i) schedule the first 10 QVD reloads to run at the same time, (ii) schedule the second 10 QVD reloads to run when #10 (or whichever is the longest) is completed; (iii) schedule the application reloads to start when #20 (or whichever is the longest in the second group) is completed. This would allow you to maximize parallel processing of the tasks.

Does this help?

Tricks for scheduling dependent tasks

rwunderlich — Mon, 02 Aug 2010 22:08:23 GMT

Hi Glad,

Thanks for the response. I don't think it will give me the required certainty. The applicaton reloads would run even if #15 -- somewhere in the middle of the pack -- had failed or not completed.

-Rob

Tricks for scheduling dependent tasks

vgutkovsky — Tue, 03 Aug 2010 17:54:28 GMT

Ah, well to solve that you would use a combination of triggers and dependecies. The triggers would be set up as described above. Then you would make the applications dependent on tasks 1 - 20. This would ensure that they would only run if all QVDs reloaded successfully. Alternatively, if a certain application is dependent on less than all the QVDs, you could make fewer dependencies. This might be a little annoying to set up for each application, but it would give you the certainty you are looking for.

Cheers,

Tricks for scheduling dependent tasks

rwunderlich — Fri, 06 Aug 2010 01:06:57 GMT

I haven't found the Dependencies feature useful, perhaps I am misunderstanding it's application. A dependency seems to be satisified if the dependent task is in any state but "Failed". Therefore the dependent task runs if the dependency ran sucessfully in the past, or even if it never ran. I need some way to say "the dependency must have run today". Can I do that with dependencies?

-Rob

Tricks for scheduling dependent tasks

vgutkovsky — Fri, 06 Aug 2010 01:26:14 GMT

Rob,

You're mostly correct. Dependencies will be satisfied if the last execution ran successfully. But by scheduling the QVD loads to run before the application loads you will ensure that the tasks will be started first and the last task state will be the most recent (today).

Tricks for scheduling dependent tasks

mike_garcia — Mon, 09 Aug 2010 18:38:14 GMT

Ok, here's an idea. Not tested really.

Make each of the 20 taks generate a txt file or write something somewhere. For Example Task A, at the end of the script, will write a txt File that says "Hey I already did my job", a counter of some sort.

That, in turn, (also at the end of the script) will execute a vbs that checks if the tasks have all done their job (count the number of files or something). If so, it will trigger an EDX for the final reload, if not it will wait for the next finished task to call it and check again.

OR, maybe you could read the task result logs, and apply the same logic.

Hope this helps. And please, let us know if it worked.

Mike.

Tricks for scheduling dependent tasks

pablolabbe — Mon, 09 Aug 2010 18:47:13 GMT

What Qliktech has to say about this feature change ?

How it´s possible to migrate from one version to another when the newer version have missing features ?

Tricks for scheduling dependent tasks

suniljain — Mon, 09 Aug 2010 22:43:42 GMT

Dear Rob,

One way to do this is make .bat file and write all task one by one in that batch file according to requirement.

Make QVW Application for QVD and then QVW.

Regards

Sunil Jain.

Tricks for scheduling dependent tasks

Thu, 26 Aug 2010 11:17:54 GMT

Hi Rob,

Did you ever find a solution to you dependent task problem ? I'm facing an almost identical scenario.

Rgds,

Nik

Tricks for scheduling dependent tasks

Thu, 26 Aug 2010 12:36:30 GMT

Please try this and let me know if it works:

In the qvw, which is scheduled after the qvds are refreshed, add this line to the start of the script:

if (qvdcreatetime (qvdpath) = today(),

the entire script

else

exit script

Idea is to check if the last qvd has refreshed, before starting the refresh of the qvw application.

Thanks,

Robinson

Tricks for scheduling dependent tasks

rwunderlich — Thu, 26 Aug 2010 18:04:50 GMT


nikidaley wrote:

Did you ever find a solution to you dependent task problem ? I'm facing an almost identical scenario.

I have not found a satisfactory solution other than having long task chains.

-Rob

Tricks for scheduling dependent tasks

rwunderlich — Thu, 26 Aug 2010 18:06:57 GMT


Robinson wrote:
Please try this and let me know if it works:
In the qvw, which is scheduled after the qvds are refreshed, add this line to the start of the script:
if (qvdcreatetime (qvdpath) = today(),

Thanks for the suggestion. I don't think it's quite what I'm looking for. I'm not try to prevent execution at the wrong time, I'm trying to execute at the right time.

-Rob

Tricks for scheduling dependent tasks

Anonymous — Thu, 26 Aug 2010 21:00:19 GMT

Rob,

We went round and round with trying to do this in publisher. We ended up abondoning triggered tasks and creating an external program that executed each task via EDX call. Then you can monitor the task for completion.

Hopefully Version 10 will have some of this functionality back.

Tricks for scheduling dependent tasks

Fri, 27 Aug 2010 09:55:50 GMT

Hi JS,

Could you elaborate please on how you monitor for the task completion from your external program ?

Rgds

Nik

Tricks for scheduling dependent tasks

Tue, 31 Aug 2010 16:31:01 GMT

Hi,

You can have an external command that deletes some flag files "del folder\flag*.qvd"

"On successful execution" of this external command will fire the 20 reloads. Each will store a QVD file, and in the very end create a flag file flag_1.qvd with one row (content does not matter).

One of the parallel will trigger on sucesful execution the main reload. This will count how many flag files there are, sleep and retry until there are enough. You do this a fixed amount of time, so there is no infinite loop.

for i= 1 to 10

set cnt=0;

for each x in filelist('folder\flag*.qvd')

set cnt = cnt + 1;

if cnt < 20

sleep 1000 * 60 * 10; //10 minutes?

//else

//is there a short circuit "break" statement to quit the loop?

end if

-Alex

Tricks for scheduling dependent tasks

Fri, 01 Oct 2010 13:16:32 GMT

Rob,

Did you ever get a resolution for your post about running app reloads after all 20 QVDs reloaded ? I am facing the same thing. We are on 8.5 and are moving to 9 but we have to rebuild our entire scheduling process because of this exact same thing....

Tricks for scheduling dependent tasks

rwunderlich — Tue, 05 Oct 2010 01:26:36 GMT


pshicks wrote:Did you ever get a resolution for your post about running app reloads after all 20 QVDs reloaded ? I am facing the same thing. We are on 8.5 and are moving to 9 but we have to rebuild our entire scheduling process because of this exact same thing....

No, I have not come up with a satisfactory solution. I'm stil running long task chains.

-Rob

Tricks for scheduling dependent tasks

Tue, 05 Oct 2010 14:34:57 GMT

I don't know if this works in 8.5, but i have used for 10 months in V9 and i guess it could be changed, so it would look at more than only one file.

What i have been using this script for, is to check that all the calculations has finished in MS Dynamics. It check for a file every minute for 6 hours. This can be changed in the script.

This is the only reasonable solution I have been able to come up with. It needs some kind of checkfiles and you need a process to remove alle the checkfiles, when the load has started (so you are ready for the next day). However, it is easy to create a simple .bat-file and start this via "EXECUTE" in the script.

/Martin