定时任务多进程处理队列，会不会引起并发问题

首先，祝所有程序员节日快乐。

我们的架构是这样的：
用户下单，产生队列
利用workerman的定时任务监控队列（40个进程 每秒执行一次）
定时任务里处理订单逻辑完成下单，向app发送通知

我的问题是会不会有多个进程同时拿到一个队列任务的情况。

另外，我在php start stop的时候产生了exit with status 9的错误

2017-10-24 13:29:17 pid:20771 Workerman stop
2017-10-24 13:29:17 pid:20771 Workerman is stoping ...
2017-10-24 13:29:17 pid:18710 Workerman Stopping ...
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 worker exit with status 9
2017-10-24 13:29:19 pid:18710 Workerman has been stopped
2017-10-24 13:29:19 pid:20771 Workerman stop success

我不知道是不是因为我自己业务逻辑的问题导致阻塞，请不吝赐教