Increased Time to Download as PDF from Tableau Server 2020.1+
Published: 26 Feb 2021 Last Modified Date: 26 Feb 2021
Performance of PDF generation after upgrade from Tableau Server 2019.2.3 to 2020.2.4 may be degraded when the data extracts are created from SQL Server and published to Tableau Server.
As an example, the export to pdf in version 2019.2.3 takes 1:17 min, while after server upgrade to version 2020.2.4 the same report takes 5 minutes.
Creating a fresh data connection after upgrade reduces PDF generation to half (2.40 min), although, it is still not expected.
With the embedded data source in workbook, the download is almost same as old server.
The difference is not noticeable for smaller sample files comprising of 1-2 sheets due to simpler structure and smaller dataset.
Tableau Server 2020.2 and 2020.3
MS SQL Server
For Tableau Server 2020.2 and 2020.3 Change the feature flag setting to enable AbstractQueryCache. TSM commands to enable AbstractQueryCache in 2020.2 and 2020.3:
tsm configuration set -k features.AbstractQueryCache -v true tsm pending-changes apply
The second command restarts Tableau Server.
Note: Disabling the AbstractQueryCache was reported to have improved performance for some scenarios so re-enabling it may lose those performance gains. Therefore, you need to verify the performance is satisfactory for other workbooks before disabling it on the production server. AbstractQueryCache is not available in Tableau Server 2020.4+ and the above workaround does not work.
The workbook in this case had a large number of ISMEMBEROF expressions which much of the time was spent trying to determine if the expression referenced a user and was therefore ineligible for caching.
Re-enabling the AbstractQueryCache in version 2020.2 and 2020.3 will improve the performance. However, for 2020.4+, the AbstractQueryCache was removed so it cannot be re-enabled in those versions.
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