Antichaos
Data Visualisation, Tableau & Data Services
When you start tuning a Tableau dashboard or SQL query for performance, one thing jumps out quickly: COUNTD can slow things down.
The count-distinct is an extremely useful function which looks simple on the surface, but under the hood it forces the engine to do extra work that adds up fast. Understanding why this happens – and what alternatives you can use – makes a big difference in keeping your dashboards responsive.
[Read more…] about Why is COUNTD so slow – and how can I fix this?The order of operations in Tableau refers to the sequence in which the software processes the data and calculations in a given worksheet or visualization.
The order of operations in Tableau is the order in which Tableau performs its various actions. An action is mostly identified as a filter, but can also be a calculation or another Tableau feature which is computed.
This is Tableau’s Order of Operations:
It shows in which sequence filters are handled with by Tableau: first extract filters, than datasource, context, dimension, measure and table calculation filters.
The ‘inserts’ on the right are calculations themselves.