What should I do to properly remove 'event' entries from Thingsboard?
As far as I know, the current API does not provide a way to remove events. It seems like the only way is to directly delete the records in DB.
By the way, I'm using PostgreSQL as DB.
Your assumption is correct. You will need to execute a SQL script to cleanup the "events" table. I must note that for Cassandra DB we already have "cassandra.query. ts_key_value_ttl" and "cassandra.query.events_ttl" configuration parameter to automate this process.