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  1. JBoss Enterprise Application Platform
  2. JBEAP-3274

(7.2.0) Leaking threads, memory and physical connections from Oracle UCP

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      Oracle UCP driver has no knowledge of EAP's mechanisms of removing/adding datasources, or about reloading the server. This has the following impacts, which occur if the UCP data source is removed, or if the server is reloaded

      1. Thread leak. UCP worker threads are left hanging doing nothing. For using the data source again, new worker threads are created.

      2. Memory leak. After removing the data source, the classes which were loaded for it aren't garbage collectible.

      3. Connection leak. Physical connections from the old pool are not closed. This can ultimately lead to reaching maximum number of active connections, so new connection attempts will be refused (or there will be an OOME)

      • This is even worse if ONS is enabled, because the ONS connection is not closed either. After reloading, UCP driver will create new ONS connections to each server in the database cluster, but there are still the old ones active. For some reason that I don't precisely understand, this leads to an exception when attempting to use the new pool (which is created after reload):
      10:24:36,293 WARN  [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (management-handler-thread - 2) IJ000604: Throwable while attempting to get a new connection: null: javax.resource.ResourceException: IJ031084: Unable to create connection
      	at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createLocalManagedConnection(LocalManagedConnectionFactory.java:361)
      	at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.getLocalManagedConnection(LocalManagedConnectionFactory.java:368)
      	at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:285)
      	at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.createConnectionEventListener(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:1336)
      	at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.getConnection(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:501)
      	at org.jboss.jca.core.connectionmanager.pool.AbstractPool.internalTestConnection(AbstractPool.java:1079)
      	at org.jboss.jca.core.connectionmanager.pool.strategy.OnePool.testConnection(OnePool.java:93)
      	at org.jboss.as.connector.subsystems.common.pool.PoolOperations$TestConnectionInPool.invokeCommandOn(PoolOperations.java:234)
      	at org.jboss.as.connector.subsystems.common.pool.PoolOperations$1.execute(PoolOperations.java:90)
      	at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:890)
      	at org.jboss.as.controller.AbstractOperationContext.processStages(AbstractOperationContext.java:659)
      	at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:370)
      	at org.jboss.as.controller.OperationContextImpl.executeOperation(OperationContextImpl.java:1341)
      	at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:392)
      	at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:217)
      	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.doExecute(ModelControllerClientOperationHandler.java:207)
      	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.access$300(ModelControllerClientOperationHandler.java:129)
      	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:151)
      	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:147)
      	at java.security.AccessController.doPrivileged(Native Method)
      	at javax.security.auth.Subject.doAs(Subject.java:422)
      	at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:92)
      	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1.execute(ModelControllerClientOperationHandler.java:147)
      	at org.jboss.as.protocol.mgmt.AbstractMessageHandler$ManagementRequestContextImpl$1.doExecute(AbstractMessageHandler.java:363)
      	at org.jboss.as.protocol.mgmt.AbstractMessageHandler$AsyncTaskRunner.run(AbstractMessageHandler.java:465)
      	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
      	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
      	at java.lang.Thread.run(Thread.java:745)
      	at org.jboss.threads.JBossThread.run(JBossThread.java:320)
      Caused by: java.sql.SQLException: Exception occurred while getting connection: oracle.ucp.UniversalConnectionPoolException: All connections in the Universal Connection Pool are in use
      	at oracle.ucp.util.UCPErrorHandler.newSQLException(UCPErrorHandler.java:488)
      	at oracle.ucp.util.UCPErrorHandler.throwSQLException(UCPErrorHandler.java:163)
      	at oracle.ucp.jdbc.PoolDataSourceImpl.getConnection(PoolDataSourceImpl.java:943)
      	at oracle.ucp.jdbc.PoolDataSourceImpl.getConnection(PoolDataSourceImpl.java:873)
      	at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createLocalManagedConnection(LocalManagedConnectionFactory.java:316)
      	... 28 more
      Caused by: oracle.ucp.UniversalConnectionPoolException: All connections in the Universal Connection Pool are in use
      	at oracle.ucp.util.UCPErrorHandler.newUniversalConnectionPoolException(UCPErrorHandler.java:368)
      	at oracle.ucp.util.UCPErrorHandler.throwUniversalConnectionPoolException(UCPErrorHandler.java:49)
      	at oracle.ucp.util.UCPErrorHandler.throwUniversalConnectionPoolException(UCPErrorHandler.java:80)
      	at oracle.ucp.util.UCPErrorHandler.throwUniversalConnectionPoolException(UCPErrorHandler.java:131)
      	at oracle.ucp.common.UniversalConnectionPoolImpl.borrowConnectionWithoutCountingRequests(UniversalConnectionPoolImpl.java:386)
      	at oracle.ucp.common.UniversalConnectionPoolImpl.borrowConnectionAndValidate(UniversalConnectionPoolImpl.java:168)
      	at oracle.ucp.common.UniversalConnectionPoolImpl.borrowConnection(UniversalConnectionPoolImpl.java:143)
      	at oracle.ucp.jdbc.JDBCConnectionPool.borrowConnection(JDBCConnectionPool.java:157)
      	at oracle.ucp.jdbc.PoolDataSourceImpl.getConnection(PoolDataSourceImpl.java:931)
      	... 30 more
      

      This exception seems to occur at random times and doesn't seem to go away, so connection attempts will fail randomly.
      While the exception message says "All connections in the Universal Connection Pool are in use", this is not correct. It's not possible to create even a single connection.

            msimka@redhat.com Martin Simka
            jmartisk@redhat.com Jan Martiska
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              Created:
              Updated:
              Resolved: