Apropos my attempt to use the data explorer plugin to query post approval times, I discovered some
queued_posts that had been both approved and rejected.
SELECT q.id, q.state, q.approved_at, q.rejected_at, approvers.username, rejecters.username FROM queued_posts q JOIN users approvers ON approvers.id = q.approved_by_id JOIN users rejecters ON rejecters.id = q.rejected_by_id WHERE q.approved_at is not null AND q.rejected_at is not null AND queue='default'
It turned up three posts whose
rejected_at values were within one second of each other, indicating to me that a race condition is possible (was possible? the last one was from May 2018) when two disagreeing moderators attempt to approve and reject the same post at approximately the same time.