4 Replies Latest reply: Jul 31, 2015 10:45 AM by Colin Albert RSS

    Tasks running slow at random times

    Denis Woods



      I have about 20 scheduled tasks, some run once a day some run every hour or so. There are few that just fail and then work fine when they run the next time.


      I've had a look at the Task History for the tasks that run every hour and the Duration is random, it will say it completes in 2 minutes then the next time it runs it can take up to 20 minutes. Most of the tasks are connecting to the same server and there does not seem to be any issues on the server it connects to?


      The client build 11.0.11414.0


      Microsoft Windows Server 2003 R2

      Enterprise x64 Edition

      Service Pack


      Six-Core AMD Opteron(tm)

      Processor 8431

      2.41 GHz, 63.9 GB of RAM


      Any ideas why they would have random runnable times? Is there anything I should be checking out for?



        • Re: Tasks running slow at random times
          Marcus Sommer

          I assume that your server had to different times a different consumption of cpu+ram+network. Beside them your server is an AMD which could struggle on this what meant the server isn't always able to divide the task on all cores and is sometimes using only one core. AFAIK this is a known incompatibility between AMD and QV and using AMD as cpu is not recommended. Maybe you could improve this behavior with some server settings.


          The link is quite old and not explicit AMD related but it could be a hint for you for what you should looking for:


          Quick tips #8 - Server Settings For Best Performance


          - Marcus

          • Re: Tasks running slow at random times

            One thing I found that helped when I had tasks randomly fail and then work the next time was to change the heap size in regedit.  It is recommended to change it from 768 to 2048.  Where and how to do this can be found on pg 113 of the latest QlikView server reference manual.

            • Re: Tasks running slow at random times
              Bill Britt

              Hi Denis,


              To start you are on a release that is over two years old. Being you have only 6 cores, you can only run 5 processes at a time. Anything above that will cause you issues.



              • Re: Tasks running slow at random times
                Colin Albert

                Can you set your reloads so a task runs on completion of another task rather than running at the same time.


                One other thought, if your scripts are accessing data from a database, could there be locks that cause the query to be held until a lock is released. Can you use a NOLOCK hint possibly.


                As Bill bbt mentioned, QlikView 11.0 is an old version and you should look at the options to upgrade.