Postgres::Drop connections

--List all of the open connections to a given database
select * from pg_stat_activity where datname='database';

--Drop all of the open connections to a given database:
select pg_terminate_backend(procpid) from pg_stat_activity where datname='database';
--More samples
select * from pg_stat_activity where date(backend_start)='2011-04-19';
select pg_terminate_backend(procpid) from pg_stat_activity where date(backend_start)='2011-04-19';

--One sample more specific
select * from pg_stat_activity where backend_start < '2011-05-04 10:00' and waiting=false order by backend_start desc
select pg_terminate_backend(procpid) from pg_stat_activity where backend_start < '2011-05-04 10:00' and waiting=false

select pg_terminate_backend(procpid) from pg_stat_activity where backend_start < '2011-08-05 07:00' and datname='' and waiting=false

References:
http://www.postgresql.org/docs/current/static/functions-admin.html#FUNCTIONS-ADMIN-SIGNAL-TABLE
http://www.postgresql.org/docs/8.4/static/monitoring-stats.html#MONITORING-STATS-VIEWS-TABLE