max_connections parameter: too_many_connections error

Hello,

We are working on a payments systems which uses postgreSql 9.6 as backend DB and blockchain technology. The database is setup in HA in master-standby mode using pacemaker on Linux 7.6.

We are new to postgres and need help in deciding how to set value for max_connections on DB.

1. How can we decide on optimal value for max_connections for a given setup/server? I checked many posts saying that even 1000 is considered as a very high value but we are hitting the error too_many_connections due to Max_connections value limit.

2. We usee hikari pool on the client side but that even has limitations. Implementing pg_bouncer is another suggestion in the posts. In a HA setup, do we have to set it up on both primary standby?

Please provide your advice/suggestions.

Thanks.