Since merge_request_diff_commits and merge_request_diff_files are so exceptionally large, inventory and add indices that will help with quantifying the merge request life cycle, as well as all other database operations (such as deletion )
Given that adding indices to this table has caused incidents in the past (gitlab-com/gl-infra/production#4823 (closed)), we should consider carefully whether we need them here or not.
Further, the original use case I had here was to improve DELETEing extraneous data or in researching the impact of such action, however I don't know that we're at a point where we need to have these created, at least not right away (and possibly not in %15.11)
@phikai I am going to move this out of %15.11 due to changing priorities. I'll move it to %16.0 for now so we can revisit it during the next planning session.