add an index to the ghost column
What does this MR do?
Adds an index to the :ghost column for users.
Are there points in the code the reviewer needs to double check?
Why was this MR needed?
Only one user ever has :ghost set to true, and we look that up using User.ghost pretty frequently. Without an index, this will perform a full table scan.
Bookmarking for later: if we begin to add more categories of users in this way, I suggest we refactor out to a single record in a dedicated table, say global_entities, that has a column for each unique user/other entity.
Screenshots (if relevant)
Does this MR meet the acceptance criteria?
- Tests
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All builds are passing
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Conform by the merge request performance guides -
Conform by the style guides -
Branch has no merge conflicts with master(if it does - rebase it please) -
Squashed related commits together