Sub-ticket of MARS-131 Mars DB hygiene (no IO risk, found in 06-15 Disk-IO self-check): (1) VACUUM ANALYZE teacherComisionMemberships (65d stale, 19.7% dead); (2) lower autovacuum_vacuum_scale_factor on notifications (high churn); (3) drop unused idx_st_createdbyuserid on supportTickets (0 scans, 13 rows); (4) index users.comisionId when query plans warrant. All reversible, audit pre-apply DDL review. · mars