Right now, Migrion doesn’t do anything special here it prints which migration is running and blocks until the database finishes.

For example, if you’re adding an index on a 10TB table, you’d just see:

Applying abc123: add index...

…and it will hang there until the database completes the operation.

That said, this is mostly a database-level concern, not something a migration tool can fully abstract away.

If you’re working with large tables, you’d typically want to use:

CREATE INDEX CONCURRENTLY (Postgres)

regardless of which migration tool you’re using.

Migratex generates the SQL, but you can edit it before applying. So in practice, you’d replace:

CREATE INDEX ...

with:

CREATE INDEX CONCURRENTLY ...

in your up.sql.

That said, there are a few things we could improve here:

Show elapsed time per migration

Add a --dry-run flag to preview what would run

Add a --statement-timeout option

These are now on the roadmap.