Migrate to CockroachDB

MOLT Fetch supports various migration flows using MOLT Fetch modes.

Migration flow	Mode	Description	Best for
Bulk load	--mode data-load	Perform a one-time bulk load of source data into CockroachDB.	Testing, migrations with planned downtime
Load and replicate	MOLT Fetch + MOLT Replicator	Load source data using MOLT Fetch, then replicate subsequent changes using MOLT Replicator.	Minimal downtime migrations
Resume replication	--mode replication-only	Resume replication from a checkpoint after interruption.	Resuming interrupted migrations, post-load sync
Failback	--mode failback	Replicate changes from CockroachDB back to the source database.	Rollback scenarios

Bulk load

For migrations that tolerate downtime, use data-load mode to perform a one-time bulk load of source data into CockroachDB. Refer to Bulk Load.

Migrations with minimal downtime

To minimize downtime during migration, MOLT Fetch supports replication streams that sync ongoing changes from the source database to CockroachDB. Instead of performing the entire data load during a planned downtime window, you can perform an initial load followed by continuous replication. Writes are only briefly paused to allow replication to drain before final cutover. The length of the pause depends on the volume of write traffic and the amount of replication lag between the source and CockroachDB.

• Use MOLT Fetch for data loading followed by MOLT Replicator for replication. Refer to Load and replicate.

Recovery and rollback strategies

If the migration is interrupted or you need to abort cutover, MOLT Fetch supports safe recovery flows:

• Use replication-only to resume a previously interrupted replication stream. Refer to Resume Replication.
• Use failback to reverse the migration, syncing changes from CockroachDB back to the original source. This ensures data consistency on the source so that you can retry later. Refer to Migration Failback.

See also

• Migration Strategy
• MOLT Releases