**昨天新装的mysql 每次第一次连接时候都报错如下:**
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.io.EOFException
STACKTRACE:
java.io.EOFException
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1913)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2304)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2803)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1573)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1665)
at com.mysql.jdbc.Connection.execSQL(Connection.java:3118)
at com.mysql.jdbc.Connection.setAutoCommit(Connection.java:5215)
原因及解决方法:
这个问题主要原因是应用服务器很长时间没有连接mysql,超过了mysql设置的最大超时时间,再连接mysql就会出现这个问题。mysql默认设置是8小时,一般网站白天都有人访问,从夜里到早上一般都会超过8小时,所以再来访问就会这个问题。
简单的解决办法就是修改最大超时时间,比如改为12小时或10小时,这样恰好避免了无人访问的时段,这里修改为10小时,方法如下:
mysql> show variables like ‘%timeout’;
±---------------------------±------+
| Variable_name | Value |
±---------------------------±------+
| connect_timeout | 10 |
| delayed_insert_timeout | 300 |
| innodb_lock_wait_timeout | 50 |
| innodb_rollback_on_timeout | OFF |
| interactive_timeout | 28800 |
| net_read_timeout | 30 |
| net_write_timeout | 60 |
| slave_net_timeout | 3600 |
| table_lock_wait_timeout | 50 |
| wait_timeout | 28800 |
±---------------------------±------+
10 rows in set (0.00 sec)
mysql> set wait_timeout = 36000;
Query OK, 0 rows affected (0.00 sec)
mysql> set interactive_timeout = 36000;
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like ‘%timeout’;
±---------------------------±------+
| Variable_name | Value |
±---------------------------±------+
| connect_timeout | 10 |
| delayed_insert_timeout | 300 |
| innodb_lock_wait_timeout | 50 |
| innodb_rollback_on_timeout | OFF |
| interactive_timeout | 36000 |
| net_read_timeout | 30 |
| net_write_timeout | 60 |
| slave_net_timeout | 3600 |
| table_lock_wait_timeout | 50 |
| wait_timeout | 36000 |
±---------------------------±------+
10 rows in set (0.00 sec)