Fix N+1 queries when loading participants for a commit note

We saw about 10,000 SQL queries for some commits in the NewNoteWorker, which stalled the Sidekiq queue for other new notes. The notification service took up to 8 minutes to process the commits. Avoiding this N+1 query brings the time down significantly.

Closes #45526 (closed)

changed the description

changed milestone to %10.7

Given this really hurt us today, I think we should pick this into 10.7.1 at the latest.

mentioned in issue #45526 (closed)

approved this merge request

added database label

mentioned in commit a313aece

merged

Picked into https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18500, will merge into 10-7-stable ready for 10.7.1

mentioned in commit def7611f

mentioned in issue gitlab-org/release/tasks#180 (closed)

added devopsplan label