This page describes the MOLT (Migrate Off Legacy Technology) tools. For more information about migrating to CockroachDB, see Migration Overview.
Use the MOLT tools to:
- Convert a schema for compatibility with CockroachDB.
- Load test and production data into CockroachDB.
- Validate queries on CockroachDB.
- Perform a cutover to finalize the migration to CockroachDB.
MOLT tools
| Tool | Usage | Supported sources | Release status |
|---|---|---|---|
| Schema Conversion Tool | Schema conversion | PostgreSQL, MySQL, Oracle, SQL Server | GA |
| Fetch | Initial data load; continuous replication | PostgreSQL, MySQL, CockroachDB | GA |
| Verify | Data validation | PostgreSQL, MySQL, CockroachDB | Preview |
| Live Migration Service | Migration cutover | PostgreSQL, MySQL, CockroachDB | Preview |
Schema Conversion Tool
The MOLT Schema Conversion Tool converts a source database schema to a CockroachDB-compatible schema. The supported Schema Conversion Tool sources are PostgreSQL, MySQL, Oracle, and SQL Server.
The tool will convert data definition (DDL) syntax (excluding destructive statements such as DROP), identify unimplemented features and syntax incompatibilities in the schema, and suggest edits according to CockroachDB best practices.
Fetch
MOLT Fetch moves data from a source database into CockroachDB. Data is moved via one-time bulk ingestion, which is optionally followed by continuously streaming replication. The supported Fetch sources are PostgreSQL, MySQL, and CockroachDB.
You can use MOLT Fetch to load test data into CockroachDB, enabling you to test your application queries on CockroachDB. When you're ready to conduct the migration in a production environment, use MOLT Fetch to move your source data to CockroachDB. You can also enable continuous replication of any changes on the source database to CockroachDB.
Verify
MOLT Verify checks for discrepancies between the source and target schemas and data. It verifies that table structures, column definitions, and row values match between the source and target. The supported Verify sources are PostgreSQL, MySQL, and CockroachDB.
Use MOLT Verify after loading data with MOLT Fetch to confirm that the CockroachDB data matches the source.
Live Migration Service
The MOLT Live Migration Service (LMS) routes traffic among an application, a source database, and a target CockroachDB database. You can use the LMS to control which database acts as the "source of truth", serving reads and writes to an application.
When you have sufficiently tested your application on CockroachDB, use the LMS to perform a transactionally consistent cutover, thus switching the source of truth to CockroachDB. The supported LMS sources are PostgreSQL, MySQL, and CockroachDB.
See also
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