Tableau - How to query large data sources efficiently?

Question

I am new to Tableau, and having performance issues and need some help. I have a query that joins several large tables. I am using a live data connection to a MySQL db.

The issue I am having is that it is not applying the filter criteria before asking MySQL for the data. So it is essentially doing a SELECT * from my query and not applying the filter criteria to the where clause. It pulls all the data from MySQL db back to Tableau, then throws away the un-needed data based on my filter criteria. My two main filter criteria are on account_id and a date range.

I can cleanly get a list of the accounts from just doing a select from my account table to populate the filter list, then need to know how to apply that selection when it goes to pull the data from the main data query from MySQL.

Answer 1

To apply a filter at the data source first, try using context filters.

Performance can also be improved by using extracts.

Answer 2

I would personally use an extract, go into your MySQL DB Back-end, run the query, and a CREATE TABLE extract1 AS statement, or whatever you want to call your data table.

When you import this table into Tableau it will already have a SELECT * of your aggregate data in the workbook. From here your query efficiency will be increased ten fold.

Unfortunately, it's going to take awhile for Tableau processing time + mySQL backend DB query time = Ntime to process your data.

Try the extracts...

Answer 3

I've been struggling with the very same thing. I have found that the tableau extracts aren't any faster than pulling directly from a SQL table. What I have done is within SQL created tables that already have the filtered data in them, so the Select * will have only the needed data. The downside to this is it takes up more space on the server, but this isn't a problem on my side.

Answer 4

For the Large Data sets Tableau recommend using an Extract. An extract will create a snapshot of the data that you are connected with and processing on this data will be faster than a live connection.

All the charts and visualization will load faster and saves your time, each time when you go to the Dashboard.

For the filters that you are using to filter the data-set will work faster in an extract connection. But to get the latest data you have to refresh the extract or schedule a refresh in the server ( if you are uploading the report to server).

There are multiple type of filters available in Tableau, the use of which depends on your application, context filters and global filters can be use to filter the whole set of data.