3 Replies Latest reply on Nov 30, 2018 3:36 PM by Mehdi Charehsazan

    Do individual schedules run serially or in parallel

    Eric Liong

      Hi all,


      I've been trying to find out if you have one schedule that takes an extremely long time does that individual schedule run each email on backgrounders in parallel?


      For example: My analyst has a report that somehow runs for 5 minutes before it loads on our server. This has a user filter on it and has subscribed each person related to this filter. Looking in the server status each subscription task or email for this report takes 1000 seconds to run. Last attempt this schedule ran hours until it was delivered to all the users.


      Now I am working with them to find out why this report runs so slow. (Many, many LODs on LODs etc). In the mean time is it expected that this should run for 1000s X Number of subscribed users? I assumed by parallel it would use all 8 of my backgrounders to run this single report subscription.


      Our system is a 16 core Server with 8 Backgrounders, and over 250 GB ram. We generally run nearly a hundred individual subscriptions in a single scheduled task but the report that has been built has extremely long load times. I also realize this is primarily an issue with the report but would like to understand whether this is expected behavior on the server.


      I tried looking at the online help articles but they never specify if parallel or serial refers to splitting tasks or splitting A task.

      Extract Refresh Schedules





        • 1. Re: Do individual schedules run serially or in parallel
          Jeff Strauss

          If you have admin rights, you should be able to see the execution of the subscriptions within the backgrounder non-extract dashboard.  I just looked at mine, the schedule is defined as parallel, and it does appear that there are some subscriptions running in parallel, but we only have 4 backgrounders.



          • 2. Re: Do individual schedules run serially or in parallel
            Donna Coles

            Hi Eric

            We have 4 background tasks and lots of schedules running at various times of both subscriptions and extract refreshes  which are set to 'parrallel'.  When it comes to extracts, I have definitely observered a the tasks within a single schedule set to parallel using all 4 of the background tasks.

            When it comes to subscriptions though, it's a bit harder to tell from what I can see of our data (because the subscriptions run at a similar time to extracts and are of lower priority).  Looking closely I can see that the subs are running on different backgrounders at times which suggests there may be some parrallelism happening as Jeff has seen.  However, if there are mutiple users subscribed to same report on the same subscription schedule, these all seem to be using the same backgrounder, which seems to support your observations too.  Might be worth raising a ticket to Tableau Support to get the definitive answer and then post back here so we can all know.




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            • 3. Re: Do individual schedules run serially or in parallel
              Mehdi Charehsazan

              Hi Eric,


              Tableau doesn't support cache pooling, it is user based, that means the same report will be cashed once for each user instead of caching it once and use that cache for all users. I have had the same problem with subscription as well. One of our report had 90 subscriptions and it would take about an hour and half for all emails to be sent out. Therefore I created a separate user (service account user) and created subscription for this user. next I redirected the new subscription from this new user (service account user) to all 90 users. It is a work around so Tableau server will only sends one email subscription instead of 90 emails.