Mysql 错误日志中突然发现大量的Got an error reading communication packets

grep "Got an error reading communication packets" error_log_3356.err |wc -l        

360    

比较基线的参数文件，发现log_warnings有变化

mysql> select @@log_warnings;
+----------------+
| @@log_warnings |
+----------------+
|              2 |
+----------------+
1 row in set (0.00 sec)


mysql> set global log_warnings=0;
Query OK, 0 rows affected (0.00 sec)


mysql> select @@log_warnings;
+----------------+
| @@log_warnings |
+----------------+
|              0 |
+----------------+
1 row in set (0.00 sec)

官方文档对log_warnings的解释

Print out warnings such as Aborted connection... to the error log. This option is enabled (1) by default. To disable it, use --log-warnings=0. Specifying the option without a level value increments the current value by 1. Enabling this option by setting it greater than 0 is recommended, for example, if you use replication (you get more information about what is happening, such as messages about network failures and reconnections). If the value is greater than 1, aborted connections are written to the error log, and access-denied errors for new connection attempts are written

http://dev.mysql.com/doc/refman/5.6/en/server-options.html#option_mysqld_log-warnings