Database Fundamentals

Process Reminders

• Ask: "Have you triggered the db:gitlabcom-database-testing pipeline?"
• For new or modified queries: raw SQL and query plans should be documented in the MR description
• For creating or dropping tables/views: ensure the Database Dictionary is updated
• Flag all modified or new ActiveRecord scopes as needing a database reviewer

Verify Before Flagging

When a diff modifies or replaces an existing structure, always verify the current state from an authoritative source before flagging a discrepancy. Never infer the pre-change state solely from diff context — check the actual source of truth. For example:

• Migration down methods: verify the down schema against the actual pre-migration schema by querying the local PostgreSQL database (\d tablename) or, if unavailable, reading the schema from the base branch (git show master:db/structure.sql).
• Table or column modifications: verify what currently exists before claiming something was lost or changed incorrectly.