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* An 'extract' connection is a connection with a static database, which is refreshed every day/hour/period. All dat is copied from the datasource to Tableau Server. Refreshing the datasource will not give you the latest data - you have to refresh the extract to get these.
* A live connection will query the underlying data in the datasource/database - refreshing the visualisation will give you the latest results. No data is copied to Tableau Server for pre-processing.
Is this clear for you?
3 of 3 people found this helpful
Extract - you pull data to your PC and do all stuff in optimized way.
Live - you make all stuff on database, so performance is dependent on database.
1 of 1 people found this helpful
Helpful links to get better idea and performance
Does it mean by choosing EXTRACT, the changes in my database (such as an Excel file) will not influence the data in tableau whereas by choosing LIVE, it will?
If you make INCREMENTAL extract then it won't affect. If you do FULL REFRESH it will do. Live is always live, it always brings data that are fresh.
This makes complete sense, but not what I am seeing.
Tableau Data source in workbook has "live" radio selected (for the record thought there is an extract on the server, but I assume that I am not using it since it I selected "live").
My worksheet is clearly not returning data that is in the underlying data source.
I run a worksheet with some previously unused parameters that uses this data source, whist running SQL profiler against the data warehouse which is the underlying data source. Nothing. No connections at all. I test my profiler trace by issuing a direct SQL query. Shows up in the trace just fine. Data source is set to a live connection in the workbook and is 100% not using my underlying live data.
Just a friendly reminder that live connection doesn't mean it's live streaming data - your data will only refresh when a query was issued. Tableau is not a live streaming too, it's a query-based tool.
Thanks John. But if I issue a query with parameters never used before on a workbook I have just opened, shouldn't that hit the database source? Perhaps I'm missing what you were saying.
Yes, that should do it.
4 of 4 people found this helpful
I think I know exactly what you are looking for.
I have ran into similar things in the past. So when you have your data sources that are published on the server and when you have a workbook pointing to it with the radio button selected as "Live", it means that it is just a connection to that data source and it is not a live connection to the actual database. A live connection to the datasource (not database) is just a connection to pull the most recent data from the last refersh of that data source available on server.
Using Extract vs publishing Data Sources directly on server has only one benefit, i.e. the same data source on server can be used by multiple Tableau workbooks/reports.
Does that help?
yes, that's really helpful. thanks!!!
Thanks Hrvoje, that really helps