Get Postgres active connections, and drop the idle ones

drop_connection.sql

-- PostgreSQL 9.1 and below:
SELECT pg_terminate_backend(pg_stat_activity.procpid)
FROM pg_stat_activity
WHERE pg_stat_activity.datname = 'TARGET_DB'
  AND procpid <> pg_backend_pid();

-- PostgreSQL 9.2 and above:
SELECT pg_terminate_backend(pg_stat_activity.pid)
FROM pg_stat_activity
WHERE pg_stat_activity.datname = 'TARGET_DB'
  AND pid <> pg_backend_pid();

get_connections.sql

-- get connections to current db
SELECT datname, usename, procpid, client_addr, waiting, query_start, current_query 
FROM pg_stat_activity;