1 Reply Latest reply on Nov 24, 2013 4:24 PM by Russell Christopher

    Use Tableau Data Extract as data source

    Jeff Lin

      We are working on creating a model using Tableau data extract as data source.  The extract is located on a network drive.  My question is, does Tableau need to load the entire file before we can consume the data.  So if the data extract is 2GB, does it read through the entire 2GB into memory initially.


      How about using MS-SQL view as data source?  if we are connecting to a view that suppose to take 1 hour to return data without any filter, do we have to wait a hour plus the time to read in all of the return data before we can work on the model? 

        • 1. Re: Use Tableau Data Extract as data source
          Russell Christopher

          Hi Jeff!


          When you use a data extract, we only load columns into memory that are necessary to answer the question being asked, so the answer to your question is "no". Having folks connect to an extract directly over the network is generally a bad idea, however. You want the file local so we can get in and out of it as quickly possible and so that Tableau isn't at the mercy of your network.


          If your database gives you very poor response time, then Tableau will also give you poor performance UNLESS you create an extract off of the view in SQL Server. There's no way for Tableau to "guess" at what the resultset that is coming back from SQL Server will be, so we need to wait for the query to return results to us.


          Hope this helps.