2 Replies Latest reply on Aug 4, 2017 9:59 AM by Jayson Osmars

    Rerun Extraction Required?

    Jayson Osmars

      Hi everyone.

       

      My DBA just added a new field concatenating UPC with UOM due to data integrity issues for PK and FK on the fact and product tables.

       

      I originally set the join to UPC on both tables.

       

      I recognize joining the new PK - Fk I'd need to rerun the extraction which would take hours.  She mentioned she just concatenated the 2 fields for the new one.

       

       

       

      My question for the experienced people since I'm pretty fresh with the tool, If I just do a join clause of the 2 fields, or just join the new field itself, would I require rerunning the extraction?  Or just an incremental (no new data has been pulled) or it picks it up dynamically and no extraction action required.

       

      Thank you everyone!  You have been very helpful for me!

        • 1. Re: Rerun Extraction Required?
          Ben Neville

          It's hard to picture without an example of before and after, but here's my opinion:

           

          If she just added a column and didn't alter the column(s) you used for joins, that's no problem - incremental should be fine (as long as you don't care about picking up the new column). If she adjusted the logic in both columns you use for the join, but they still match each other you will now have new data in the columns, and an incremental extract will only pick up the new rows based on your key field configured during the incremental refresh step. However, if you aren't joining on a date field, that means that old records have the old values, so if they should be joined with the new records, that's not likely to happen.

           

          In my opinion, your best bet is to re-run a full extract to be safe. Tableau, like most analytics tools, is not very flexible when you change the underlying data structure beyond the contents of the columns themselves. If they no longer join in the same fashion, names change, or if datatypes change you're likely to get some weird behavior. If you have Tableau Server, you can push this extract to that machine so that it doesn't tie up your own computer.

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          • 2. Re: Rerun Extraction Required?
            Jayson Osmars

            She told me she did some data cleanup name/address fixes etc.

             

            So Full Extraction is needed regardless.

             

            Thanks for your help Ben Neville