flywayschemahistory

Flyway schema history refers to the built-in mechanism used by the Flyway database migration tool to record which migrations have been applied to a target database. This history acts as the system of record for the database’s evolving schema, enabling Flyway to determine which migrations are already in place, which remain to be executed, and whether the migration state is consistent. The history is typically persisted in a dedicated table in the target database, commonly named flyway_schema_history, and is updated automatically as migrations run.

The history table contains metadata about each migration. Typical columns include installed_rank (the order in which migrations were applied), version (the migration version), description (a human-readable description), type (the migration kind, such as SQL or JDBC), script (the filename of the migration), checksum (a hash of the migration script), installed_by (the user who applied the migration), installed_on (a timestamp of when it was applied), execution_time (the duration of the migration), and success (a flag indicating whether the migration completed successfully). Together these fields allow Flyway to audit migrations, verify integrity, and reproduce the exact sequence of changes.

In practice, the schema history enables Flyway to plan future migrations, verify script integrity on repeated runs, and detect drift or changes to already-applied migrations. If a migration’s script is altered after application, the checksum may no longer match, prompting action such as repair or reapplication depending on configuration. Manual edits to the history table are discouraged; use Flyway repair or other supported operations to maintain consistency. Proper management includes securing access, backing up the history, and ensuring consistent histories across environments.