The edit and editor tables have yes_votes, no_votes and edits_accepted, edits_rejected, auto_edits_accepted, edits_failed columns, respectively, that are materialized (in Perl) versions of data already existing elsewhere. Their purpose is, of course, to speed up access to these numbers, e.g. when displaying a user profile.
This materialization also has some disadvantages, however. Most importantly, each vote submitted/each edit entered or decided requires an update of the tables, which can mean that an updated copy of the row is inserted and the old row deleted; this causes table bloat and can move related entries apart (the latter mostly relevant for edit), hurting performance. Furthermore, the numbers can get out of sync with reality (cf.
This materialization isn't really needed: User profiles already include the number of votes, of cancelled edits, etc. for which no materialization exists. Moreover, Postgres 9.2+ has index-only scans that can heavily improve the performance of counting queries (if an appropriate index is available, which we would need to verify/add; cf. MBS-8718).
We should therefore simply remove those columns.