一、错误日志

2022-08-30 03:14:45
org.apache.flink.streaming.runtime.tasks.AsynchronousException: Caught exception while processing timer.
    at org.apache.flink.streaming.runtime.tasks.StreamTask$StreamTaskAsyncExceptionHandler.handleAsyncException(StreamTask.java:1214)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.handleAsyncException(StreamTask.java:1190)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.invokeProcessingTimeCallback(StreamTask.java:1329)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.lambda$null$17(StreamTask.java:1318)
    at org.apache.flink.streaming.runtime.tasks.StreamTaskActionExecutor$1.runThrowing(StreamTaskActionExecutor.java:50)
    at org.apache.flink.streaming.runtime.tasks.mailbox.Mail.run(Mail.java:90)
    at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.processMail(MailboxProcessor.java:317)
    at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:189)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:619)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:583)
    at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:758)
    at org.apache.flink.runtime.taskmanager.Task.run(Task.java:573)
    at java.lang.Thread.run(Thread.java:748)
Caused by: TimerException{org.apache.flink.streaming.runtime.tasks.ExceptionInChainedOperatorException: Could not forward element to next operator}
    ... 11 more
Caused by: org.apache.flink.streaming.runtime.tasks.ExceptionInChainedOperatorException: Could not forward element to next operator
    at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.pushToOperator(CopyingChainingOutput.java:88)
    at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.collect(CopyingChainingOutput.java:46)
    at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.collect(CopyingChainingOutput.java:26)
    at org.apache.flink.streaming.api.operators.CountingOutput.collect(CountingOutput.java:50)
    at org.apache.flink.streaming.api.operators.CountingOutput.collect(CountingOutput.java:28)
    at org.apache.flink.streaming.api.operators.TimestampedCollector.collect(TimestampedCollector.java:50)
    at org.apache.flink.streaming.api.functions.windowing.PassThroughAllWindowFunction.apply(PassThroughAllWindowFunction.java:35)
    at org.apache.flink.streaming.runtime.operators.windowing.functions.InternalSingleValueAllWindowFunction.process(InternalSingleValueAllWindowFunction.java:48)
    at org.apache.flink.streaming.runtime.operators.windowing.functions.InternalSingleValueAllWindowFunction.process(InternalSingleValueAllWindowFunction.java:34)
    at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.emitWindowContents(WindowOperator.java:577)
    at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.onProcessingTime(WindowOperator.java:533)
    at org.apache.flink.streaming.api.operators.InternalTimerServiceImpl.onProcessingTime(InternalTimerServiceImpl.java:284)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.invokeProcessingTimeCallback(StreamTask.java:1327)
    ... 10 more
Caused by: java.sql.SQLException: connection disabled
    at com.alibaba.druid.pool.DruidPooledConnection.checkStateInternal(DruidPooledConnection.java:1185)
    at com.alibaba.druid.pool.DruidPooledConnection.checkState(DruidPooledConnection.java:1170)
    at com.alibaba.druid.pool.DruidPooledConnection.setAutoCommit(DruidPooledConnection.java:718)
    at com.meiyijia.pd.flink.meta.sink.dwd.MySQLSinkToOptions.invoke(MySQLSinkToOptions.java:73)
    at com.meiyijia.pd.flink.meta.sink.dwd.MySQLSinkToOptions.invoke(MySQLSinkToOptions.java:21)
    at org.apache.flink.streaming.api.operators.StreamSink.processElement(StreamSink.java:54)
    at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.pushToOperator(CopyingChainingOutput.java:71)
    ... 22 more
Caused by: com.mysql.cj.jdbc.exceptions.CommunicationsException: The last packet successfully received from the server was 41,094,955 milliseconds ago. The last packet sent successfully to the server was 41,094,955 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
    at com.mysql.cj.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:2056)
    at com.alibaba.druid.pool.DruidPooledConnection.setAutoCommit(DruidPooledConnection.java:729)
    at com.meiyijia.pd.flink.meta.sink.dwd.MySQLSinkToOptions.invoke(MySQLSinkToOptions.java:38)
    ... 25 more
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: The last packet successfully received from the server was 41,094,955 milliseconds ago. The last packet sent successfully to the server was 41,094,955 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
    at com.mysql.cj.protocol.a.NativeProtocol.send(NativeProtocol.java:569)
    at com.mysql.cj.protocol.a.NativeProtocol.sendCommand(NativeProtocol.java:624)
    at com.mysql.cj.protocol.a.NativeProtocol.sendQueryPacket(NativeProtocol.java:940)
    at com.mysql.cj.protocol.a.NativeProtocol.sendQueryString(NativeProtocol.java:886)
    at com.mysql.cj.NativeSession.execSQL(NativeSession.java:1073)
    at com.mysql.cj.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:2046)
    ... 27 more
Caused by: java.net.SocketException: Broken pipe (Write failed)
    at java.net.SocketOutputStream.socketWrite0(Native Method)
    at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:111)
    at java.net.SocketOutputStream.write(SocketOutputStream.java:155)
    at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
    at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
    at com.mysql.cj.protocol.a.SimplePacketSender.send(SimplePacketSender.java:55)
    at com.mysql.cj.protocol.a.TimeTrackingPacketSender.send(TimeTrackingPacketSender.java:50)
    at com.mysql.cj.protocol.a.NativeProtocol.send(NativeProtocol.java:560)
    ... 32 more

二、原因分析

　　客户端连接超时，请设置客户端超时时间wait_timeout或配置连接失效后自动连接autoReconnect=true

三、解决

1、mysql5以上的，设置autoReconnect=true 是无效的 只有4.x版本，起作用

2、即使在创建Mysql时url中加入了autoReconnect=true参数,一但这个连接两次访问数据库的时间超出了服务器端wait_timeout的时间限制,还是会CommunicationsException: The last packet successfully received from the server was xxx milliseconds ago.

3、服务器端的参数可以用如下参数进行设置,但是wait_timeout值不应该设的太高

show global variables like 'wait_timeout';
set global wait_timeout=10;

4、较好的策略是对处于idle状态的connection定时发送一个sql,来刷新服务器上的时间戳.这可以使用c3p0r的连接，如果连接闲置8小时 (8小时内没有进行数据库操作), mysql就会自动断开连接, mysql数据库有一个wait_timeout的配置，默认值为28800(即8小时). 在默认配置不改变的情况下，如果连续8小时内都没有访问数据库的操作，再次访问mysql数据库的时候，mysql数据库会拒绝访问

四、参考地址

https://blog.csdn.net/qq_21137441/article/details/102916199