I have spent most of my (limited) career scaling PostgreSQL with (IMO) surprisingly good results. Most recently I have been using Citus and it has been ridicul

I have spent most of my (limited) career scaling PostgreSQL with (IMO) surprisingly good results. Most recently I have been using Citus and it has been ridiculously easy to shard data. To be fair I have only been exposed to workloads of a few Terabytes of data ingest a day so YMMV. Unfortunately, I can't compare to Mongo as I have had somewhat limited experience with it.