Force $ rake db:reset Despite Other Users with Postgres

Question

Is there a way to force a database reset even if Postgres has other users using it. I almost always get this error when I try a $ rake db:reset:

 Couldn't drop example_database_name :
 #<ActiveRecord::StatementInvalid: PG::Error: ERROR:  database "example_database_name" is being accessed by other users DETAIL: 
 There are 2 other session(s) using the database.

Answer 1

Put this in a file lib/database.rake if you find yourself using db:reset a lot in development.

require 'active_record/connection_adapters/postgresql_adapter'
module ActiveRecord
  module ConnectionAdapters
    class PostgreSQLAdapter < AbstractAdapter
      def drop_database(name)
        raise "Nah, I won't drop the production database" if Rails.env.production?
        execute <<-SQL
          UPDATE pg_catalog.pg_database
          SET datallowconn=false WHERE datname='#{name}'
        SQL

        execute <<-SQL
          SELECT pg_terminate_backend(pg_stat_activity.pid)
          FROM pg_stat_activity
          WHERE pg_stat_activity.datname = '#{name}';
        SQL
        execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
      end
    end
  end
end

Obviously only designed for use on non-production databases. It will cause all existing db connections to be severed, so the next page load might be an error if unicorn/passenger/pow is pooling db connections. If this happens, a simple page refresh will cause the server to open a new connection and all will be well.