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我知道之前有人问过这个问题并且有很多解决方案，但没有一个对我有用，而且我的情况有点不同。
我有一台带有数据库的服务器，该数据库通过隧道连接到其他服务器。运行 ubuntu 1310 和 1204 的服务器没有任何问题。但是使用相同的设置、相同的配置、相同的应用程序，我在 1404 上遇到了这个问题。
服务器设置:
A - Ubuntu 1204 Server with MariaDB 10.0 Database
B - Ubuntu 1204 Server with MariaDB 5.5 Client -> tunneled via autossh 14c and works perfect
C - Ubuntu 1204 Server with MariaDB 5.5 Client -> tunneled via autossh 14c and works perfect
D - Ubuntu 1310 Server with MariaDB 5.5 Client -> tunneled via autossh 14c and works perfect
E - Ubuntu 1310 Server with MariaDB 5.5 Client -> tunneled via autossh 14c and works perfect
F - Ubuntu 1310 Server with MariaDB 5.5 Client -> tunneled via autossh 14c and works perfect
D - Ubuntu 1404 Server with MariaDB 5.5 Client (also tried mysql 5.5 and mariadb 10.0) -> tunneled via autossh 14c DOES NOT WORK though same setup and app:
.
2014-07-11 16:02:51 [SEVERE] com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 141 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.
2014-07-11 16:02:51 [SEVERE] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
2014-07-11 16:02:51 [SEVERE] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
2014-07-11 16:02:51 [SEVERE] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
2014-07-11 16:02:51 [SEVERE] at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.Util.handleNewInstance(Util.java:407)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1116)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3082)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2968)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3516)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1986)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2140)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2620)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:5022)
2014-07-11 16:02:51 [SEVERE] at sun.reflect.GeneratedMethodAccessor85.invoke(Unknown Source)
2014-07-11 16:02:51 [SEVERE] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2014-07-11 16:02:51 [SEVERE] at java.lang.reflect.Method.invoke(Method.java:606)
2014-07-11 16:02:51 [SEVERE] at org.apache.tomcat.jdbc.pool.ProxyConnection.invoke(ProxyConnection.java:126)
2014-07-11 16:02:51 [SEVERE] at org.apache.tomcat.jdbc.pool.JdbcInterceptor.invoke(JdbcInterceptor.java:109)
2014-07-11 16:02:51 [SEVERE] at org.apache.tomcat.jdbc.pool.DisposableConnectionFacade.invoke(DisposableConnectionFacade.java:80)
2014-07-11 16:02:51 [SEVERE] at com.sun.proxy.$Proxy76.setAutoCommit(Unknown Source)
2014-07-11 16:02:51 [SEVERE] at me.botsko.prism.actionlibs.RecordingTask.insertActionsIntoDatabase(RecordingTask.java:174)
2014-07-11 16:02:51 [SEVERE] at me.botsko.prism.actionlibs.RecordingTask.save(RecordingTask.java:35)
2014-07-11 16:02:51 [SEVERE] at me.botsko.prism.actionlibs.RecordingTask.run(RecordingTask.java:332)
2014-07-11 16:02:51 [SEVERE] at org.bukkit.craftbukkit.v1_6_R3.scheduler.CraftTask.run(CraftTask.java:58)
2014-07-11 16:02:51 [SEVERE] at org.bukkit.craftbukkit.v1_6_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
2014-07-11 16:02:51 [SEVERE] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
2014-07-11 16:02:51 [SEVERE] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
2014-07-11 16:02:51 [SEVERE] at java.lang.Thread.run(Thread.java:744)
2014-07-11 16:02:51 [SEVERE] Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2529)
2014-07-11 16:02:51 [SEVERE] at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2979)
2014-07-11 16:02:51 [SEVERE] ... 21 more
2014-07-11 16:02:51 [INFO] [Prism]: Database connection error: Communications link failure
更多 Stacktraces，始终是新应用程序 session (完全重启)的第一个异常 https://gist.github.com/Slind14/cd5a03ec289c30b1452e
由于我找不到任何解决方案，我想知道您是否知道 1310 和 1404 之间的任何变化可能会导致这种情况发生。
+-----------------------------+----------+
| Variable_name | Value |
+-----------------------------+----------+
| connect_timeout | 5 |
| deadlock_timeout_long | 50000000 |
| deadlock_timeout_short | 10000 |
| delayed_insert_timeout | 300 |
| 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 |
| slave_net_timeout | 3600 |
| thread_pool_idle_timeout | 60 |
| wait_timeout | 28800 |
+-----------------------------+----------+
更新:
当我将远程数据库保持打开一段时间时，我也得到“MySQL 服务器已经消失”，同样仅在 1404 服务器上。
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 38189
Current database: *** NONE ***