list and kill Postgres queries from a Rails console

pg_ps.rb

# list pid, execution time, and query text for running queries
def pg_ps
  now = Time.now
  ActiveRecord::Base.connection.execute("SELECT pid, query, query_start FROM pg_stat_activity WHERE state='active'").to_a.each do |q|
    printf "%8d %10.2f  %s\n", q['pid'], now - DateTime.parse(q['query_start']), q['query']
  end
  nil
end

# cancel the current query for the given process
def pg_cancel(pid)
  ActiveRecord::Base.connection.execute("SELECT pg_cancel_backend(#{pid})")
end

# kill the database connection for the given process
def pg_kill!(pid)
  ActiveRecord::Base.connection.execute("SELECT pg_terminate_backend(#{pid})")
end