# History Sync

Drop migration history rows whose files no longer exist.

### Syntax

```
$ vela migrate history-sync
```

The database records which migrations it has applied. If a migration file is deleted — a branch switch, a rebase, a squashed set of migrations — the record is left pointing at a file that isn't there. This removes those rows so the history matches what is on disk.

It only touches the history table; it does not undo anything a deleted migration did to the schema. Run [`vela migrate up`](/migrate/up) afterwards if the sync surfaces migrations that now count as pending.