早上来公司，看昨天运行的情况：
2006:MySQL server has gone away嗯？又是这个错误？为什么要又呢？因为遇到过几次了。
网上一查，先登录mysql：
mysql> show global status like 'uptime';
+---------------+--------+
| Variable_name | Value |
+---------------+--------+
| Uptime | 268306 |
+---------------+--------+
1 row in set (0.01 sec)
接着再看：
mysql> show global variables like '%timeout';
+-----------------------------+----------+
| Variable_name | Value |
+-----------------------------+----------+
| connect_timeout | 10 |
| delayed_insert_timeout | 300 |
| have_statement_timeout | YES |
| innodb_flush_log_at_timeout | 1 |
| innodb_lock_wait_timeout | 50 |
| innodb_rollback_on_timeout | OFF |
| interactive_timeout | 28800 |
| lock_wait_timeout | 31536000 |
| net_read_timeout | 30 |
| net_write_timeout | 60 |
| rpl_stop_slave_timeout | 31536000 |
| slave_net_timeout | 60 |
| wait_timeout | 28800 |
+-----------------------------+----------+
13 rows in set (0.00 sec)
再看
mysql> show global status like 'Com_kill';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Com_kill | 0 |
+---------------+-------+
1 row in set (0.01 sec)
再看：
mysql> show global variables like 'max_allowed_packet';
+--------------------+----------+
| Variable_name | Value |
+--------------------+----------+
| max_allowed_packet | 16777216 |
+--------------------+----------+
1 row in set (0.01 sec)