PG Sharding

Hi Everyone.

We are looking at a rather large fin-tech installation. But as scalability requirements are high we look at sharding of-course. 

I have looked at many sources for Postgresql sharding, but we are a little confused as to shared with schema or databases or both. 

So far our understanding:

PROS:

- seems native to PG

- backup seems easier

- connection pooling seems easier, as you can use same connection between shard.

CONS:

- schema changes seems litlle more complicated

- heard of backup and maintenance problems

- also some caching  problems.

- connection pooling is hard, as 100 shards would mean 100 pools

So what is actually the right approach? If anyone could  shed some light on my issue.