ruby – 异常：ActiveRecord :: ConnectionNotEstablished使用pu

$callback_location = (lambda do |envelop|
  begin
    case envelop.channel
      when "iwm_driver_locations"
        last_location = LatLong.where(driver_id: envelop.message['driver_id']).last
        if last_location.lat != envelop.message['lng'] and last_location.lng != envelop.message['lat']
          l = LatLong.create!(
              lat: envelop.message['lat'],lng: envelop.message['lng'],driver_id: envelop.message['driver_id']
          )
        end
      when "iwm_chat"
        m = Message.create!(
            :author => envelop.message,:message => envelop.message,:timetoken => envelop.timetoken
        )
    end
  rescue Exception => e
    Rails.logger.info "****** Exception: #{e}"
  end
end)

$pubnub.subscribe(
    :channel => ['iwm_chat','iwm_driver_locations'],:callback => $callback_location
) unless $pubnub.subscription_running?

但我的订户在一些尝试中抛出了异常ConnectionNotEstablished.但是,有时此代码执行时没有问题.

我试图增加数据库超时和池,但同样的问题仍然存在.
知道我做错了吗？