When the ePO services are restarted, the following query is executed to verify whether the post-upgrade reindexing steps have been completed.

In some scenarios, the query never exits and remains in a sleeping state indefinitely. This problem can cause the SQL TempDB database to grow until the SPID responsible for the following select statement is killed:
 
SELECT AutoID,CommandName,CommandURI FROM [dbo].[_epo_post_upgrade_async_task] WHERE Processed=0 ORDER BY AutoID