After a day grails program hangs. Need solution - mysql

Question

Here is the log. Problem occurse after a day with no interaction whatsoever. Is it the asynchronous mail plugin? is it a setting? Who can help me with this, any help is appreciated.
Grails 2.4.0, ubuntu 16.04
The last packet successfully received from the server was 278.019 milliseconds ago. The last packet sent successfully to the server was 218.021 milliseconds ago.
ERROR 2017-01-19 10:37:47,642 interceptor.TransactionInterceptor Application exception overridden by rollback exception
org.springframework.dao.RecoverableDataAccessException: Hibernate operation: could not prepare statement; SQL [update async_mail_mess set status=? where end_date<? and (status=? or status=?)]; Communications link failure
The last packet successfully received from the server was 278.019 milliseconds ago. The last packet sent successfully to the server was 218.021 milliseconds ago.; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 278.019 milliseconds ago. The last packet sent successfully to the server was 218.021 milliseconds ago.
at grails.plugin.asyncmail.AsynchronousMailPersistenceService$_updateExpiredMessages_closure4.doCall(AsynchronousMailPersistenceService.groovy:66)
at org.grails.datastore.gorm.GormStaticApi.withTransaction(GormStaticApi.groovy:814)
at org.grails.datastore.gorm.GormStaticApi.withTransaction(GormStaticApi.groovy:714)
at grails.plugin.asyncmail.AsynchronousMailPersistenceService.updateExpiredMessages(AsynchronousMailPersistenceService.groovy:63)
at grails.plugin.asyncmail.ExpiredMessagesCollectorJob.execute(ExpiredMessagesCollectorJob.groovy:13)
at grails.plugins.quartz.GrailsJobFactory$GrailsJob.execute(GrailsJobFactory.java:104)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 278.019 milliseconds ago. The last packet sent successfully to the server was 218.021 milliseconds ago.
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1116)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3853)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2471)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2651)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2671)
at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:5024)
... 8 more
Caused by: java.net.SocketException: Broken pipe (Write failed)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:109)
at java.net.SocketOutputStream.write(SocketOutputStream.java:153)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3834)
... 12 more
ERROR 2017-01-19 10:37:47,642 listeners.ExceptionPrinterJobListener Exception occurred in job: Grails Job
org.quartz.JobExecutionException: org.springframework.transaction.TransactionSystemException: Could not roll back Hibernate transaction; nested exception is org.hibernate.TransactionException: rollback failed [See nested exception: org.springframework.transaction.TransactionSystemException: Could not roll back Hibernate transaction; nested exception is org.hibernate.TransactionException: rollback failed]
at grails.plugins.quartz.GrailsJobFactory$GrailsJob.execute(GrailsJobFactory.java:111)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)
Caused by: org.springframework.transaction.TransactionSystemException: Could not roll back Hibernate transaction; nested exception is org.hibernate.TransactionException: rollback failed
at grails.plugin.asyncmail.ExpiredMessagesCollectorJob.execute(ExpiredMessagesCollectorJob.groovy:13)
at grails.plugins.quartz.GrailsJobFactory$GrailsJob.execute(GrailsJobFactory.java:104)
... 2 more
Caused by: org.hibernate.TransactionException: rollback failed
... 4 more
Caused by: org.hibernate.TransactionException: unable to rollback against JDBC connection
... 4 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Communications link failure during rollback(). Transaction resolution unknown.
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1013)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
at com.mysql.jdbc.ConnectionImpl.rollback(ConnectionImpl.java:4757)
... 4 more
ERROR 2017-01-19 10:38:09,620 spi.SqlExceptionHelper Communications link failure

Answer 1

It could be because of two reasons
1.) your grails box got disconnected from the network.
2.) Your database server stops.

Answer 2

You can add configuration parameters to your dataSource config to ensure the DB connection is kept alive
dataSource {
properties {
validationQuery=SELECT 1 FROM DUAL
validationQueryTimeout=3
validationInterval=15000
}
}
The validationQuery will depend on your database vendor e.g. the above works with Oracle