Comment 3 for bug 1692120

The main problem is that the planner can't accurately estimate the number of workitems due to one of the assignee filters being on the wrong side of a join, causing it to end up retrieving all workitems and all specifications and filtering those down. This runs into a growing performance issue with ACL checks for Canonical employees that are in lots of teams.

https://pastebin.canonical.com/189802/ has three variants of the query which attempt to mitigate the issues. I suspect the last one will be <50ms.