View the original community article here
Last tested: Sep 2, 2020
There is currently a limit of one query for how many queries can be run against the internal DB at once, for both i__looker (changed in v7.10) and System Activity.
You can increase this concurrency limit by either opting in to Elite System Activity or by increasing the internal DB start up flag after setting up a read replica internal analytics database.
This content is subject to limited support.