同步延迟告警
【*****************】主从同步延迟过高，告警阈值300，当前为1973】，请及时处理！,产生时间2022-09-30 06:51:27
ERRO日志
2022-09-30T06:50:16.110234+08:00 32196300
[Note] Multi-threaded slave statistics for channel '': seconds elapsed = 121; events assigned = 454740993; worker queues filled over overrun level = 0; waited due a Worker queue full = 0; waited due the total size = 0; waited at clock conflicts = 19460575157300 waited (count) when Workers occupied = 152376 waited when Workers occupied = 1026653718600
日志解析
2022-09-30T06:50:16.110234+08:00 32196300
[Note] Multi-threaded slave statistics for channel '':
seconds elapsed = 121; 每隔121s输出
events assigned = 454740993; 总共有多少event被分配执行；
worker queues filled over overrun level = 0;多线程同步中，worker 的私有队列长度超长的次数
waited due a Worker queue full = 0; 因为worker的队列超长而产生等待的次数
waited due the total size = 0; 超过最大size的次数
waited at clock conflicts = 19460575157300 在事务之间存在依赖的情况下，该参数显示等待时间相当于冲突检测和解决方案的逻辑时间。
waited (count) when Workers occupied = 152376 因为workder被占用而出现等待的次数。（总计值）
waited when Workers occupied = 1026653718600 因为workder被占用而出现等待的总时间，总计值，单位是纳秒
解决方式
1、调大slave_pending_jobs_size_max
如果slave_pending_jobs_size_max的大小小于当前需要执行事件所需的内存大小
2、临时调整sync_binlog大小
当每进行n次事务提交之后，MySQL将进行一次fsync之类的磁盘同步指令来将binlog_cache中的数据强制写入磁盘
3、slave_parallel_workers
调整并行复制的参数，建议修改为cpu的核数
4、innodb_io_capacity
sas硬盘建议200，如果是固态盘，建议调整为1500