Re: monitoring tool

1) pgwatch2 - excellent metrics / performance dashboard - easy to configure  https://www.cybertec-postgresql.com/en/products/pgwatch2/

2) pghero -  great for highlighting problems at the db level - easy to configure as well - https://github.com/ankane/pghero

pgdash is supposed to be very good - https://pgdash.io/

netdata is an awesome product - more of a system monitoring tool but it does have a postgres plugin - this tool is very slick   -  https://github.com/firehol/netdata/wiki

datadog is another system wide metrics tool - very impressive - https://docs.datadoghq.com/integrations/postgres/