10 Replies Latest reply on Jun 15, 2018 2:56 AM by Daniel Ward

    Data Blend Not Updating Worksheet Content

    Daniel Ward

      I have a bit of a weird issue, which I'm looking for help with. I'm using Tableau 10.4.

       

      I have two data sources I've blended together. Some dashboards use the first data source, and some use the blend. The second data source is a custom SQL query.

       

      What I'm finding is: When I refresh the extract (or run all from Live), only worksheets using non-blended data are updating. Blended data worksheets do not update at all. If I completely rebuild the blended data worksheet from scratch, then the updated data will display.

       

      It's difficult for me to upload a packaged workbook due to anonymising data, but if required I'll give it a shot. In the mean time, please see the attached screenshots to understand the issue slightly better. As is expected, in the second screenshot, the 6th, 7th, and 8th of June have changed to ticks.

      Original:

      Built after refresh:

        • 1. Re: Data Blend Not Updating Worksheet Content
          Mavis Liu

          Hi Daniel,

           

          Please could you provide us with more details of the data source? For example, have both data sources been extracted?

          Are you working with a twbx file? What is the data source which the custom sql is running against?

           

          Thanks,

           

          Mavis

          • 2. Re: Data Blend Not Updating Worksheet Content
            Daniel Ward

            Thanks for the reply, Mavis.

             

            The first data source is an extract of a set of MS SQL tables, running off a handful of joins.

             

            The second data source is purely custom SQL. It calls on one of the tables used in the first data source, but performs a level of aggregation. This is also run as an extract.

             

            I have also tried using both in Live, rather than by extracts, with no change in behaviour.

             

            I'm working with .twb files. The extracts are held locally.

             

            I've attached the code I'm using in the custom SQL (obviously anonymised). Apologies as it's not the cleanest, I've had to retype it out due to dev environment security, and anonymise field names...

            • 3. Re: Data Blend Not Updating Worksheet Content
              Mavis Liu

              Hi Daniel,

               

              Just to check, when you run that script directly from the database, does it give you the results you want?

               

              Thanks,

               

              Mavis

              • 4. Re: Data Blend Not Updating Worksheet Content
                Daniel Ward

                Hi Mavis,

                 

                Yes, run directly on the database, the script does exactly what I want. It also does exactly what I need it to in Tableau.

                 

                I think the issue is closer to the secondary data source... This is the information that isn't updating, purely for the blended worksheet. It's almost as if the worksheet is acting off a "snapshot" of data and won't update / refresh.

                 

                Also, both the "Date" and "Weekday" fields have relationships set up correctly with the secondary data source.

                • 5. Re: Data Blend Not Updating Worksheet Content
                  Mavis Liu

                  Hi Daniel,

                   

                  Sorry I was referring to the secondary data source previously. I recall that this used a custom sql query. I was just checking that if you copied this query and used it directly, whether it worked or not.

                   

                  If you create a separate worksheet using JUST the secondary data source, are the results correct then?

                   

                  Lastly, what are the steps you're doing to refresh the extract? It should be data->refresh all extracts

                   

                  Thanks,

                   

                  Mavis

                  • 6. Re: Data Blend Not Updating Worksheet Content
                    Daniel Ward

                    Hi Mavis,

                     

                    I have absolutely no idea why, but as of a moment ago, it's decided to work. I haven't changed anything, but sheets are updating themselves. I think I might've relaunched Tableau (it's been a busy morning and I literally can't remember if I did), but I relaunched and rebooted last night to no effect.

                     

                    I'll keep an eye on this and let you know if anything changes.

                     

                    For reference, I was refreshing using data -> Refresh all extracts. Also apologies as I wasn't clear with the original description: My "first" data source is comprised of three tables, which is used as the secondary data source on this worksheet. The "second" data source is a single custom SQL query (in the attached code above), which is the primary datasource on the worksheet. I should have described them the other way round but for most things in the workbook, the 3 table join has been my only data source used.

                     

                    Thanks for your help,

                     

                    Dan

                    • 7. Re: Data Blend Not Updating Worksheet Content
                      Daniel Ward

                      I've just run the same test today and am encountering the exact same issue... Restarting Tableau unfortunately didn't help. Rebuilding a worksheet identically to the original sees the newly built worksheet showing accurate, up-to-date information, whilst the original worksheet shows older, incorrect data.

                       

                      I'm going to try creating the custom code as a View within the database and changing Tableau to run from that instead of running the custom code itself. I don't think this will help but I'm out of ideas.

                       

                      EDIT: No luck with the view. Exact same issue. One thing I haven't tried is recreating the worksheet and THEN refreshing the data, to see if neither sheet updates, or if the new one does whilst the old one doesn't.

                      • 8. Re: Data Blend Not Updating Worksheet Content
                        Mavis Liu

                        Hi Daniel,

                         

                        Really really strange! Unfortunately it'll be hard to check without having the access to the workbook and data source!

                         

                        is it possible to avoid using custom SQL and creating the view in the database and connecting directly to that?

                         

                        Thanks,

                         

                        Mavis

                        • 9. Re: Data Blend Not Updating Worksheet Content
                          Daniel Ward

                          Hi Mavis,

                           

                          Think your reply and my edit got caught up in the moderation queue!

                           

                          Creating the view in the database had no luck.

                           

                          I'm going to try the method I mentioned in my comment edit above, but I'll also start seeing about anonymising and uploading. It's very unlikely I'll be able to as we operate through RDC to a secure, remote server.

                           

                          EDIT: I'm now very certain this is a blending issue. I've noticed a separate worksheet on the same dashboard using the same set of blended data is having the same issue. I've been considering joining the data but due to a difference in granularity, this wouldn't be ideal. I'll see if I can come up with another workaround, or identify exactly why this is happening.

                          • 10. Re: Data Blend Not Updating Worksheet Content
                            Daniel Ward

                            So, it looks like there's no solution or reason for this. My solution in the end was to ignore the blend completely by building a view in SQL with everything I needed. Haven't had the issue since.

                             

                            I'm fairly certain this is a bug with Tableau, there's no reason building a whole new worksheet should provide different information, given everything is identical to the original worksheet.