It's sad that this was downvoted. It's literally true. MongoDB vs. vanilla Postgres is not in Postgres' favor with respect to horizontal scaling. It's the same situation with Postgres vs. MySQL.
That being said there are plenty of ways to shard Postgres that are free, e.g. Citus. It's also questionable whether many need sharding. You can go a long way with simply a replica.
Postgres also has plenty of its own strengths. For one, you can get a managed solution without being locked into MongoDB the company.
That being said there are plenty of ways to shard Postgres that are free, e.g. Citus. It's also questionable whether many need sharding. You can go a long way with simply a replica.
Postgres also has plenty of its own strengths. For one, you can get a managed solution without being locked into MongoDB the company.