debian-mirror-gitlab/.gitlab/merge_request_templates/Database changes.md

## What does this MR do?

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## Database checklist

- [ ] Conforms to the [database guides](https://docs.gitlab.com/ee/development/README.html#database-guides)

When adding migrations:

- [ ] Updated `db/schema.rb`
- [ ] Added a `down` method so the migration can be reverted
- [ ] Added the output of the migration(s) to the MR body
- [ ] Added tests for the migration in `spec/migrations` if necessary (e.g. when migrating data)

When adding or modifying queries to improve performance:

- [ ] Included data that shows the performance improvement, preferably in the form of a benchmark
- [ ] Included the output of `EXPLAIN (ANALYZE, BUFFERS)` of the relevant queries

When adding foreign keys to existing tables:

- [ ] Included a migration to remove orphaned rows in the source table before adding the foreign key
- [ ] Removed any instances of `dependent: ...` that may no longer be necessary

When adding tables:

- [ ] Ordered columns based on the [Ordering Table Columns](https://docs.gitlab.com/ee/development/ordering_table_columns.html#ordering-table-columns) guidelines
- [ ] Added foreign keys to any columns pointing to data in other tables
- [ ] Added indexes for fields that are used in statements such as `WHERE`, `ORDER BY`, `GROUP BY`, and `JOIN`s

When removing columns, tables, indexes or other structures:

- [ ] Removed these in a post-deployment migration
- [ ] Made sure the application no longer uses (or ignores) these structures

/label ~database ~"database::review pending"