PGmigrate is a database migration tool developed by Yandex.

PGmigrate has the following key-features:

- Transactional and nontransactional migrations: you can enjoy whole power of
  PostgreSQL DDL
- Callbacks: you can run some DDL on specific steps of migration process
  (e.g. drop some code before executing migrations, and create it back after
  migrations were applied)
- Online migrations: you can execute series of transactional migrations and
  callbacks in a single transaction (so, if something goes wrong simple ROLLBACK
  will bring you in consistent state)