Chris Webb disables a visual element:
These numbers are counts of the number of rows for each value in the table that the field is from. The query to get these counts is usually quite fast and inexpensive, but if you’re filtering on a field from a very large table (for example a fact table) and/or using DirectQuery mode that might not be true. For example, the screenshot above is taken from a DirectQuery dataset and here’s the SQL query that generates the counts shown:
Read on to see how to do this.