5 Replies Latest reply on Aug 9, 2018 7:40 AM by Pat Merkle

    Excessive memory use - system instability ensues

    Ryan Shirley

      I have only tried using Prep 3 times; each time after about 10-15 minutes of use, as I am building out a workflow using a Microsoft SQL server connection, memory use shoots through the roof and makes my system unusable.


      This last time I upgraded from 2018.1 to 2018.2 and it still did it, so its not likely a version issue.



      If I force close Prep, the Java Binary process's memory use goes up to about 3Gb of memory use. Have to force close that as well to get my system running properly again.Takes forever to get the Task Manager up in order to do so though.


      Anyone had this issue, or know of a fix?


      Thanks for the help!

        • 1. Re: Excessive memory use - system instability ensues
          Pat Merkle

          I'm having the same problem. I am cleaning an Excel survey file. It has crashed at least 5 times this morning and I am only in the first clean step, changing field names, a few very simple calculations, and changes some aliases. The table is still quite "wide" but only has less than 800 rows of data.

          • 2. Re: Excessive memory use - system instability ensues


            I have had multiple memory issues similar to the one you describe. I think there is a JAVA scripting issue within Prep. The problem is most predominate when adding steps to cleanse the data where Prep needs to display summarized data for each of the columns.


            Although it doesn't fix the real issue, what I have been doing to overcome this is create a work flow including adding steps where I know I am going to cleanse the data, but don't cleanse anything when creating.  Save the file. Close Tableau Prep and give it time to allow all the processes to close (you can watch in task manager).  Then reopen the file, then begin to cleanse under the individual steps, but keep monitoring your task manager. If you top out at greater than 98% memory usage, save the file before it locks up and close Prep. Wait for processes to close and then open it again. Each time Prep closes and the processes shut down you free up memory that Prep is not releasing during normal use for some reason.  Its not a great solution but it works.  As example I have one flow that imports 30+ text files to create unions and joins, millions of rows, >2Gb of info. The cleanse steps kept crashing the file. I did what I described above and was able to push the flow to over 4Gb of data imported.


            The final thing, and this is very important, don't create your output step until after everything else is done.



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            • 3. Re: Excessive memory use - system instability ensues
              Ryan Shirley

              Thank you for the feedback Garth. Seems like a crappy way to have to go about it haha (no knock on your workaround, its a knock on Prep itself); I can probably build it faster within MS Access than to have to keep closing and restarting the workflows as you described. Pretty unfortunate. Guess I will just wait until its a bit further along and stable before I try using it again.

              • 4. Re: Excessive memory use - system instability ensues
                Arthur Gyldenege

                Thank you for raising this issue Ryan! We're actively looking into issues like the one you mentioned here. Would you be able to share a copy of your log files so we can see what's happening? Below are the instructions for collecting and sending your log files.


                Where are the log files?

                • Windows: C:\Users\<your username>\Documents\My Tableau Prep Repository\Logs
                • Mac: /Users/<your username>/My Tableau Prep Repository/Logs


                Steps to collect log files

                1. Clear out your logs:  Go to your user directory and delete all files there.
                2. Recreate the issue: Open Tableau Prep and recreate the issue
                3. Close Tableau Prep
                4. Zip up all the new log files
                5. Attach the zip file and reply to this thread, or respond to me directly if you prefer
                • 5. Re: Excessive memory use - system instability ensues
                  Pat Merkle

                  Tableau prep is driving me crazy. I have attached the prep logs. I have to keep all of the prep flows really short and do multiple flow files to keep from crashing. I think Prep could be awesome, now it's just annoying.