从字面意思看了一下是因为slave_pending_jobs_size_max默认值为16777216（16MB），但是slave接收到的slave_pending_jobs_size_max为17085453（17M）；
解决方案
从库执行如下SQL
mysql>stop slave;
mysql>set global slave_pending_jobs_size_max=20000000;
mysql> start slave;#在多线程复制时，在队列中Pending的事件所占用的最大内存，默认为16M，如果内存富余，或者延迟较大时，可以适当调大;注意这个值要比主库的max_allowed_packet大
故障模拟：
从库设置
mysql> set global slave_parallel_workers=4;
mysql> show variables like 'slave_parallel_workers';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
|slave_parallel_workers | 4 |
+------------------------+-------+
1 row in set (0.00sec)
mysql>set global slave_pending_jobs_size_max=1024;
mysql> show variables like 'slave_pend%';
+-----------------------------+-------+
| Variable_name | Value |
+-----------------------------+-------+
|slave_pending_jobs_size_max | 1024 |
+-----------------------------+-------+
1 row in set (0.00sec)
主库操作：
mysql> update erp_mkpf set usnam='测试1864错误';
ERROR 1197 (HY000):Multi-statement transaction required more than 'max_binlog_cache_size' bytes ofstorage; increase this mysqld variable and try again
mysql> set global max_binlog_cache_size=8388608000000;
Query OK, 0 rowsaffected (0.00 sec)
mysql> begin;
Query OK, 0 rowsaffected (0.00 sec)
mysql> update erp_mkpf set usnam='测试1864错误';
Query OK, 70466 rowsaffected (0.38 sec)
Rows matched:70466 Changed: 70466 Warnings: 0
mysql> commit;
Query OK, 0 rowsaffected (0.08 sec)
从库查看状态：
mysql> show slavestatus\G
Last_SQL_Errno: 1864
Last_SQL_Error: Cannot scheduleevent Update_rows, relay-log name ./HE1-relay-bin.000005, position 494 toWorker thread because its size 8200 exceeds 1024 ofslave_pending_jobs_size_max.
