2 Replies Latest reply on Sep 7, 2018 11:20 AM by Emiliano Cenizo

    Best way to cross millions of rows on 2 datasources

    Emiliano Cenizo

      Hi People!


      So, I have just started playing with tableau and its power. I was wondering if you could help me with an efficiency issue I have:


      I have 2 datasources:


      a) A MYSQL database

      b) A Teradata server with a lot of information


      The MYSQL is the main source of info - it has around 40 million rows

      Teradata has A LOT of rows but I need just about 4 million. This database has some extra info that I need for a particular task.


      The table I need from both databases are indexed on the ID and that´s the field I have to Join.




      When I bring all the info from the MYSQL base, its all good and quick. When I try to join them by the id on the teradata source, its gets extremely slow.


      I tried:

      - Adding both as "connections" on the same Tableau Datasource (I think this is not recommended for uploading to a tableau server?)

      - Consuming them as separate Datasources, and then using the "Edit Relationships" box to "join" them by this ID)


      But its just impossible.


      The ideal way would be to "feed" the Teradata query with the resulting ids from the MYSQL query; but I cant find how (or if it will work).


      Which is the recommended way?


      Thanks a lot!