Tools and methodologies to keep to DBs aligned 2 DBs having schemas that represent the same semantic objects.
The first one is production DB (Non-RDBMS, in-house implemented in-memory DB with shitload of RAM). Other is Postgres.

Once in a while the production DB is changed (schema upgrade).

Question: what is the best practice to keep DBs of different types aligned semantically?
keep all SQL DDL in "patch" files in source control.

add a "schema_version" table to your database and track the latest patch file you are on.

write a script that runs new patches against your dbs.