Issue

• We have a problem at a customers factory. We lost DB connection more then three times. Every time we had to restart the JBoss. The last two times we checked the status of the JBoss at the JBoss console by opening the site: http://localhost:9990/console/App.html#jpa-metrics.
• If every thing is okay we can see all our persistence units. But after loosing DB connections ALL PERSISTENCE UNITS ARE DISAPPEARED. We tried to restart the DB, but this did not solve the problem.
• Our system is for multi user and multi process. We saw a lot of JDBC exceptions with description there is no connection to database. So we check DB connection JBoss admin console. DB connection was not OK. -> One minute later DB connection was OK, but there were still this JDBC exceptions.Next step was checking the persistence units in admin console, but the persistence units where not visible anymore. -> we had to restart the JBoss.
• Do you ever had a case with problems like this?
• Is it possible to configure the logging to get information about error of persistence units?
  after noticing DB connection (or PU disappeared) I just tested DB connection in JBoss console. First test was not successful. 1 Minute later this test was successful.
• We are getting the below exceptions again and again in logs:

2015-05-27 16:22:37,318 ERROR [Test:223] could not get mfs state: javax.ejb.EJBTransactionRolledbackException: org.hibernate.exception.GenericJDBCException: could not prepare statement
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleInCallerTx(CMTTxInterceptor.java:162)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInCallerTx(CMTTxInterceptor.java:252)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:341)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:238)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
org.jboss.as.ejb3.component.singleton.SingletonComponentInstanceAssociationInterceptor.processInvocation(SingletonComponentInstanceAssociationInterceptor.java:52)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:272)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:339)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:238)

Caused by: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not prepare statement
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1387)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1310)
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:277)

    ... 82 more
Caused by: org.hibernate.exception.GenericJDBCException: could not prepare statement
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:54)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:124)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:193)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.prepareQueryStatement(StatementPreparerImpl.java:157)
    at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1881)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1858)

    ... 121 more
Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: The connection is closed.
    at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:190)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.checkClosed(SQLServerConnection.java:389)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.prepareStatement(SQLServerConnection.java:2175)
    at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnection.doPrepareStatement(BaseWrapperManagedConnection.java:748)
    ... 137 more