There is no "just" about it. The absolute key takeaway is in "what we learned":
> We chose to use DMS because it was well supported by the GOV.UK PaaS and we could also get support from AWS. If we were doing a PostgreSQL to PostgreSQL database migration in the future, we would invest more time in trying alternative tools such as pglogical. DMS potentially added more complexity, and an unfamiliar replication process than what we may have found with other tools. This backs up what AWS say themselves on PostgreSQL to PostgreSQL migrations.
Even AWS in their own docs says to use the native tools when migrating from postgres to postgres[1]. They don't go into the details to much and points to pg_dump rather than pg_logical, but interesting to see that they don't recommend using DMS for it
They do, but those recommendations are buried quite deep in the documentation, well behind all the marketing guff that suggests that DMS is all things to all people, and wonderful magic that is ideal for all situations.
> We chose to use DMS because it was well supported by the GOV.UK PaaS and we could also get support from AWS. If we were doing a PostgreSQL to PostgreSQL database migration in the future, we would invest more time in trying alternative tools such as pglogical. DMS potentially added more complexity, and an unfamiliar replication process than what we may have found with other tools. This backs up what AWS say themselves on PostgreSQL to PostgreSQL migrations.
The message here is not "just use DMS".