updates redis push to work with large messages.

        if len(res) == 0:

            raise ValueError('Query returned zero results.')

        pipeline = self.redis_queue.pipeline()

        for row in res:

        for i, row in enumerate(res):

            msg = {'along':on,

                    'id':row.id,

                    'func':function,

            msg['config'] = self.config  # Hacky for now, just passs the whole config dict

            pipeline.rpush(self.processing_queue,

                                json.dumps(msg, cls=JsonEncoder))

            if i % 1000 == 0:

                # Redis can only accept 512MB of messages at a time. This ensures that the pipe

                # stays under the size limit.

                pipeline.execute()

                pipeline = self.redis_queue.pipeline()

        pipeline.execute()

        return len(res)