I just flagged a topic here on Meta as “something else”. When you do so, a private conversation between you and moderators is created. Under the discussion, there are ‘Suggested messages’ which I am not part of. I see their titles and participants. However when I click a discussion, I get a connection error so I cannot read them which is good. Under normal messages there are messages from my own messages as it should be.
Looks like the joins are not unnecessary after all
This was actually due to a combination of PERF: Avoid unnecessary expensive joins if possible. · discourse/discourse@f3fadf4 · GitHub and PERF: Avoid `NOT IN (<subquery>>` which can get really slow. · discourse/discourse@2814819 · GitHub
Added test cases to guard against regression.
Thanks for reporting @rizka