To improve the load times for workbooks, Tableau Server caches the results of queries included in workbooks. For most workbooks, query results are computed and cached when they are first viewed by a user on Tableau Server. However, for workbooks that connect to data extracts, Tableau Server can recompute query results when the corresponding extract refresh tasks run. This reduces the load time for these workbooks when they are first viewed, so this option is turned on by default for workbooks that have been viewed recently.
Important! External query cache warmup will be deprecated in version 2023.1. To improve view load times for workbooks, you should allow View Acceleration on your site instead. For more information, see View Acceleration.
Determine the performance impact
Although this option reduces the initial load time for workbooks, recomputing query results also increases the load on Tableau Server. If your Tableau Server installation is already performance-constrained, you might want to turn this option off or lower the threshold for workbook caching.
Here are some possible reasons why you might want to turn this option off or lower the threshold:
The Background Tasks for Non Extracts administrative view displays many long-running jobs in the Warming up external query cache on data change category.
The Background Task Delay administrative view displays long delays.
CPU and memory consumption for the backgrounder processes is consistently high.
However, note that this is only one of the options that impacts the performance of background tasks. For more information about performance, see Performance.
Turn off workbook caching for the server
To decrease the load on Tableau Server, you can turn off workbook caching after a scheduled refresh at the server-level. If you turn this option off, Tableau Server caches query results for workbooks the first time the workbooks are viewed.
Use the following tsm configuration set option to turn off workbook caching after a scheduled refresh:
For more information on how to use and apply tsm set options, see tsm configuration set Options.
Turn off workbook caching for a site
You can also turn off workbook caching after a scheduled refresh for an individual site. For example, you might do this if there is one site in particular that contains many slow workbooks which increase load on the server.
Select the site for which you want to turn off workbook caching in the sites drop-down.
In the Workbook Performance after a Scheduled Refresh section, clear the check box.
Note: Although this option is available in the settings for an individual site, you must have server administrator permissions to view it.
Configure the workbook caching threshold
Tableau Server only recomputes query results for workbooks that both have scheduled refresh tasks and have been viewed recently.
You can increase or decrease the number of workbooks that are cached after a scheduled refresh with the following tsm configuration set option:
By default, the threshold is set to 2.0. The threshold is equal to the number of views that a workbook has received in the past seven days divided by the number of refreshes scheduled in the next seven days. (If a workbook has not been viewed in the past seven days, it is unlikely that it will be viewed soon, so Tableau Server does not spend resources recomputing queries for the workbook.)