Database Migration Service (DMS) Cheat Sheet

Migration Methods

  • Full load = Migrate all existing data from source to target database
  • CDC (change data capture) = Use recovery log to apply changes to a target database continuously
  • Full load + CDC = First migrate all existing data, then apply changes continuously

Settings

  • Target metadata settings
    • ParallelLoadThreads = Maximum concurrent loading for each table or view
      • Not to be confused with MaxFullLoadSubTasks which is to limit concurrent table-loading, ParallelLoadThreads limits concurrent segment/partition/subpartition-loading for each table / view
      • Target database must support parallel loading
  • Full-load settings, only applies to full-load tasks
    • MaxFullLoadSubTasks = Maximum concurrent loading tasks; NOT maximum number of tables to load

Gotchas

  • The default service role policy for DMS would allow full access to buckets with prefix dms-, for buckets with other names, user has to manually grant access.