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MOLT Fetch supports various migration flows using . For CockroachDB-to-CockroachDB migrations, contact your account team for guidance.
Migration flowModeDescriptionBest for
Bulk load--mode data-loadPerform a one-time bulk load of source data into CockroachDB.Testing, migrations with
Load and replicateMOLT Fetch + MOLT ReplicatorLoad source data using MOLT Fetch, then replicate subsequent changes using MOLT Replicator. migrations
Resume replication--mode replication-onlyResume replication from a checkpoint after interruption.Resuming interrupted migrations, post-load sync
Failback--mode failbackReplicate changes from CockroachDB back to the source database.Rollback scenarios

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Bulk load

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

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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.

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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.
  • 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.

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See also