Sometimes when working with databases you need a backup. One you can switch to quickly in case things go wrong. I find this particularly helpful when testing out data migrations.
Here are a few SQL commands I use to accomplish this.
Look at Database Size
Copy A Database
CREATE DATABASE sitepixel_backup1 WITH TEMPLATE sitepixel;
View Active Connections
SELECT pid, usename, client_addr FROM pg_stat_activity WHERE datname ='sitepixel';
Terminate Active Connections
SELECT pg_terminate_backend(pg_stat_activity.pid) FROM pg_stat_activity WHERE pg_stat_activity.datname = 'sitepixel' AND pid <> pg_backend_pid()