今天搭建mysql 主從佇列，延遲時間比較長

        Seconds_Behind_Master: 47776 Master_SSL_Verify_Server_Cert: No                 Last_IO_Errno: 0                 Last_IO_Error:                 Last_SQL_Errno: 0                Last_SQL_Error:    Replicate_Ignore_Server_Ids:               Master_Server_Id: 1000                   Master_UUID: 74d738a1-b62f-11e8-86a7-a0369ff53354              Master_Info_File: mysql.slave_master_info                     SQL_Delay: 0           SQL_Remaining_Delay: NULL       Slave_SQL_Running_State: Waiting for dependent transaction to commit            Master_Retry_Count: 86400

通過監控日誌發現了很長的note 記錄一下：

2018-09-13T02:41:26.069970Z 25 [Note] Multi-threaded slave statistics for channel '': seconds elapsed = 252; events assigned = 1025; worker queues filled over overrun level = 0; waited due a Worker queue full = 0; waited due the total size = 0; waited at clock conflicts = 11582222100 waited (count) when Workers occupied = 0 waited when Workers occupied = 0 2018-09-13T02:43:26.738761Z 25 [Note] Multi-threaded slave statistics for channel '': seconds elapsed = 120; events assigned = 73729; worker queues filled over overrun level = 0; waited due a Worker queue full = 0; waited due the total size = 0; waited at clock conflicts = 130894105700 waited (count) when Workers occupied = 5 waited when Workers occupied = 131145300 2018-09-13T02:45:26.230192Z 25 [Note] Multi-threaded slave statistics for channel '': seconds elapsed = 120; events assigned = 179201; worker queues filled over overrun level = 0; waited due a Worker queue full = 0; waited due the total size = 0; waited at clock conflicts = 248748357600 waited (count) when Workers occupied = 5 waited when Workers occupied = 131145300 2018-09-13T02:47:29.039700Z 25 [Note] Multi-threaded slave statistics for channel '': seconds elapsed = 123; events assigned = 280577; worker queues filled over overrun level = 0; waited due a Worker queue full = 0; waited due the total size = 0; waited at clock conflicts = 369673169800 waited (count) when Workers occupied = 5 waited when Workers occupied = 131145300 2018-09-13T02:49:33.520110Z 25 [Note] Multi-threaded slave statistics for channel '': seconds elapsed = 124; events assigned = 449537; worker queues filled over overrun level = 0; waited due a Worker queue full = 0; waited due the total size = 0; waited at clock conflicts = 491909458900 waited (count) when Workers occupied = 10 waited when Workers occupied = 136565800

seconds elapsed 就是上一次統計跟這一次統計的時間間隔

events assigned：總共有多少個event被分配執行，計的是總數。worker queues filled over overrun level：多執行緒同步中，worker 的私有佇列長度超長的次數，計的是總數。waited due a Worker queue full ：因為worker的佇列超長而產生等待的次數，計的是總數。waited due the total size ：超過最大size的次數，這個由引數slave_pending_jobs_size_max  指定。waited at clock conflicts