Only single thread can create JDBC connection at once in JBoss EAP 5.2

Solution Verified - Updated

Environment

  • JBoss Enterprise Application Platform (EAP) 5.2.0

Issue

  • A threaddump shows that all request threads are blocked in an attempt to get a connection from the DB connection pool.

  • A single thread in a synchronized block is creating a database connection

    ...
   java.lang.Thread.State: RUNNABLE
	at oracle.jdbc.driver.T2CConnection.t2cCreateState(Native Method)
	at oracle.jdbc.driver.T2CConnection.logon(T2CConnection.java:414)
	at oracle.jdbc.driver.PhysicalConnection. (PhysicalConnection.java:546)
	at oracle.jdbc.driver.T2CConnection. (T2CConnection.java:162)
	at oracle.jdbc.driver.T2CDriverExtension.getConnection(T2CDriverExtension.java:53)
	at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:521)
	at org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory.getLocalManagedConnection(LocalManagedConnectionFactory.java:207)
	at org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:195)
	- locked <0x0000000782cd9730> (a org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory)
	at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.createConnectionEventListener(InternalManagedConnectionPool.java:650)
	at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.getConnection(InternalManagedConnectionPool.java:273)
	at org.jboss.resource.connectionmanager.JBossManagedConnectionPool$BasePool.getConnection(JBossManagedConnectionPool.java:689)
	at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:404)
	at org.jboss.resource.connectionmanager.TxConnectionManager.getManagedConnection(TxConnectionManager.java:424)
	at org.jboss.resource.connectionmanager.BaseConnectionManager2.allocateConnection(BaseConnectionManager2.java:496)
	at org.jboss.resource.connectionmanager.BaseConnectionManager2$ConnectionManagerProxy.allocateConnection(BaseConnectionManager2.java:941)
	at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:96)
	...

  • Many other threads are blocked waiting for access to the connection

    ...
   java.lang.Thread.State: BLOCKED (on object monitor)
        at org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:171)
        - waiting to lock <0x0000000782cd9730> (a org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory)
        at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.createConnectionEventListener(InternalManagedConnectionPool.java:650)
        at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.getConnection(InternalManagedConnectionPool.java:273)
        at org.jboss.resource.connectionmanager.JBossManagedConnectionPool$BasePool.getConnection(JBossManagedConnectionPool.java:689)
        at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:404)
        at org.jboss.resource.connectionmanager.TxConnectionManager.getManagedConnection(TxConnectionManager.java:424)
        at org.jboss.resource.connectionmanager.BaseConnectionManager2.allocateConnection(BaseConnectionManager2.java:496)
        at org.jboss.resource.connectionmanager.BaseConnectionManager2$ConnectionManagerProxy.allocateConnection(BaseConnectionManager2.java:941)
        at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:96)
        ...

Resolution

Please raise a support case to discuss a fix.

Root Cause

  • This is a known defect Content from issues.jboss.org is not included.JBPAPP-10968.
  • Resolution for a deadlock vulnerability added synchronization which serialized attempts to create JDBC connections.
  • The degree to which this issue impacts a system is dependent on the time taken by the database to create connections.
    • Slow creation or hangs during database connection creation may result in noticeable slowdown for application threads.
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