central/docs/migrations.md
2026-05-17 04:08:20 +00:00

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# Migration policy
## Migrations must be idempotent
New migration files (007+) must use guards so they can be safely
re-run without error:
- `CREATE TABLE IF NOT EXISTS ...`
- `CREATE INDEX IF NOT EXISTS ...`
- `INSERT ... ON CONFLICT DO NOTHING` (or `ON CONFLICT ... DO UPDATE`
where the intent is upsert)
- `ALTER TABLE ... ADD COLUMN IF NOT EXISTS ...`
Migrations 003-006 predate this policy and are grandfathered. Do not
rewrite them.
## All schema changes go through migrate.py
Direct `psql` execution bypasses the `schema_migrations` tracker and
was the cause of the v0.2.0 reconcile. If a migration needs to be
applied on the live system, run:
sudo -u central /opt/central/.venv/bin/python -m scripts.migrate
Never apply migration SQL directly via `psql`, even as a superuser,
even "just to test." If migrate.py has a bug that's blocking you, fix
migrate.py.