mysql5.7的错误日志中最常见的note级别日志解释

mysql5.7从库多线程报错：

2018-02-25T07:11:52.613073Z 11 [Note] Multi-threaded slave statistics for channel '': seconds elapsed = 124; events assigned = 211909633; worker queues filled over overrun level = 165380; waited due a Worker queue full = 69203; waited due the total size = 1987; waited at clock conflicts = 0 waited (count) when Workers occupied = 9003466 waited when Workers occupied = 0

我们通过源代码，找到下面一段，该段实现了上述日志的输出。

  if ((my_now – rli->mts_last_online_stat)>=

           mts_online_stat_period)

        {

         sql_print_information(“Multi-threadedslave statistics%s: “

                                “seconds elapsed = %lu; “

                                “events assigned = %llu; “

                                “worker queues filled over overrun level = %lu;”

                                “waited due a Worker queue full = %lu; “

                                “waited due the total size = %lu; “

                                “waited at clock conflicts = %llu “

                               “waited(count) when Workers occupied = %lu “

                                “waited when Workers occupied = %llu”,

                                rli->get_for_channel_str(),

                                static_cast<unsignedlong>

                                (my_now – rli->mts_last_online_stat),

                                rli->mts_events_assigned,

                                rli->mts_wq_overrun_cnt,

                                rli->mts_wq_overfill_cnt,

                                rli->wq_size_waits_cnt,

                                rli->mts_total_wait_overlap,

                                rli->mts_wq_no_underrun_cnt,

                                rli->mts_total_wait_worker_avail);

          rli->mts_last_online_stat=my_now;   

 当(my_now – rli->mts_last_online_stat) >= mts_online_stat_period时,会实现打印日志,以及最后一句rli->mts_last_online_stat=my_now,打印日志后重新将my_now赋值给rli->mts_last_online_stat;   可以得知， seconds elapsed 就是上一次统计跟这一次统计的时间间隔。

而mts_online_stat_period =120秒，硬代码，因此就是几乎每隔120秒，就有上述日志的输出。

http://blog.youkuaiyun.com/isoleo/article/details/54342180