Are you running live against a database or against an extract? I am wondering if somehow parallel queries are coming into action with your upgrade and somehow it's getting contention within the database.
Thanks for your reply. We are running against extracts. At the moment we are investigating the antivirus setup. I fired up four Command Prompt windows on the Tableau Server machine and in each ran a series of tabcmd export commands. Before too long, the commands running in two of the windows hang. Consistently, fifteen minutes later, the command processing continues. Trend Micro Office Scan is installed on the machine. Although this was installed after Tableau Server, we have since upgraded Tableau Server, and I wonder whether the new installation path is not being ignored by Trend Micro. This is being checked... When I find out more I'll post again... Thanks again.