HHH-10943 - Driver Manager Connection Pool should close leaked connections upon shutting down

hibernate-core/src/main/java/org/hibernate/engine/jdbc/connections/internal/DriverManagerConnectionProviderImpl.java

@@ -52,7 +52,6 @@ public class DriverManagerConnectionProviderImpl
 
 	private boolean active = true;
 
-	private ConnectionCreator connectionCreator;
 	private ScheduledExecutorService executorService;
 	private PooledConnections pool;
 
@@ -70,7 +69,6 @@ public class DriverManagerConnectionProviderImpl
 	public void configure(Map configurationValues) {
 		log.usingHibernateBuiltInConnectionPool();
 
-		connectionCreator = buildCreator( configurationValues );
 		pool = buildPool( configurationValues );
 
 		final long validationInterval = ConfigurationHelper.getLong( VALIDATION_INTERVAL, configurationValues, 30 );
@@ -99,6 +97,7 @@ public class DriverManagerConnectionProviderImpl
 		final int maxSize = ConfigurationHelper.getInt( AvailableSettings.POOL_SIZE, configurationValues, 20 );
 		final int initialSize = ConfigurationHelper.getInt( INITIAL_SIZE, configurationValues, minSize );
 
+		ConnectionCreator connectionCreator = buildCreator( configurationValues );
 		PooledConnections.Builder pooledConnectionBuilder = new PooledConnections.Builder(
 				connectionCreator,
 				autoCommit
@@ -184,11 +183,7 @@ public class DriverManagerConnectionProviderImpl
 			throw new HibernateException( "Connection pool is no longer active" );
 		}
 
-		Connection conn = pool.poll();
+		return pool.poll();
-		if ( conn == null ) {
-			conn = connectionCreator.createConnection();
-		}
-		return conn;
 	}
 
 	@Override
@@ -232,7 +227,7 @@ public class DriverManagerConnectionProviderImpl
 			return;
 		}
 
-		log.cleaningUpConnectionPool( connectionCreator.getUrl() );
+		log.cleaningUpConnectionPool( pool.getUrl() );
 
 		active = false;
 

hibernate-core/src/main/java/org/hibernate/engine/jdbc/connections/internal/PooledConnections.java

@@ -10,6 +10,7 @@ import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.concurrent.ConcurrentLinkedQueue;
 
+import org.hibernate.HibernateException;
 import org.hibernate.internal.CoreLogging;
 import org.hibernate.internal.CoreMessageLogger;
 
@@ -18,7 +19,8 @@ import org.hibernate.internal.CoreMessageLogger;
  */
 public class PooledConnections {
 
-	private ConcurrentLinkedQueue<Connection> connections = new ConcurrentLinkedQueue<Connection>();
+	private final ConcurrentLinkedQueue<Connection> allConnections = new ConcurrentLinkedQueue<Connection>();
+	private final ConcurrentLinkedQueue<Connection> availableConnections = new ConcurrentLinkedQueue<Connection>();
 
 	private static final CoreMessageLogger log = CoreLogging.messageLogger( DriverManagerConnectionProviderImpl.class );
 
@@ -65,35 +67,50 @@ public class PooledConnections {
 	public void add(Connection conn) throws SQLException {
 		conn.setAutoCommit( true );
 		conn.clearWarnings();
-		connections.offer( conn );
+		availableConnections.offer( conn );
 	}
 
 	public Connection poll() throws SQLException {
-		Connection conn = connections.poll();
+		Connection conn = availableConnections.poll();
 		if ( conn == null ) {
-			return null;
+			synchronized (allConnections) {
+				if(allConnections.size() < maxSize) {
+					addConnections( 1 );
+					return poll();
+				}
+			}
+			throw new HibernateException( "The internal connection pool has reached its maximum size and no connection is currently available!" );
 		}
 		conn.setAutoCommit( autoCommit );
 		return conn;
 	}
 
 	public void close() throws SQLException {
-		for ( Connection connection : connections ) {
+		try {
-			connection.close();
+			int allocationCount = allConnections.size() - availableConnections.size();
+			if(allocationCount > 0) {
+				log.error( "Collection leak detected: there are " + allocationCount + " unclosed connections upon shutting down pool " + getUrl());
+			}
+		}
+		finally {
+			for ( Connection connection : allConnections ) {
+				connection.close();
+			}
 		}
 	}
 
 	public int size() {
-		return connections.size();
+		return availableConnections.size();
 	}
 
 	protected void removeConnections(int numberToBeRemoved) {
 		for ( int i = 0; i < numberToBeRemoved; i++ ) {
-			Connection connection = connections.poll();
+			Connection connection = availableConnections.poll();
 			try {
 				if ( connection != null ) {
 					connection.close();
 				}
+				allConnections.remove( connection );
 			}
 			catch (SQLException e) {
 				log.unableToCloseConnection( e );
@@ -103,10 +120,16 @@ public class PooledConnections {
 
 	protected void addConnections(int numberOfConnections) {
 		for ( int i = 0; i < numberOfConnections; i++ ) {
-			connections.add( connectionCreator.createConnection() );
+			Connection connection = connectionCreator.createConnection();
+			allConnections.add( connection );
+			availableConnections.add( connection );
 		}
 	}
 
+	public String getUrl() {
+		return connectionCreator.getUrl();
+	}
+
 	public static class Builder {
 		private final ConnectionCreator connectionCreator;
 		private boolean autoCommit;

hibernate-core/src/test/java/org/hibernate/test/tm/CMTTest.java

@@ -521,5 +521,9 @@ public class CMTTest extends BaseNonConfigCoreFunctionalTestCase {
 		TestingJtaPlatformImpl.INSTANCE.getTransactionManager().commit();
 	}
 
+	protected boolean rebuildSessionFactoryOnError() {
+		return false;
+	}
+
 }
 

hibernate-ehcache/src/test/resources/hibernate-config/hibernate.cfg.xml

@@ -23,7 +23,7 @@
         <property name="connection.password"></property>
 
         <!-- JDBC connection pool (use the built-in) -->
-        <property name="connection.pool_size">1</property>
+        <property name="connection.pool_size">5</property>
 
         <!-- SQL dialect -->
         <property name="dialect">

hibernate-jcache/src/test/resources/hibernate-config/hibernate.cfg.xml

@@ -23,7 +23,7 @@
         <property name="connection.password"></property>
 
         <!-- JDBC connection pool (use the built-in) -->
-        <property name="connection.pool_size">1</property>
+        <property name="connection.pool_size">5</property>
 
         <!-- SQL dialect -->
         <property name="dialect">

hibernate-testing/src/main/java/org/hibernate/testing/jta/JtaAwareConnectionProviderImpl.java

@@ -148,7 +148,12 @@ public class JtaAwareConnectionProviderImpl implements ConnectionProvider, Confi
 
 	private void delist(Connection connection) {
 		// todo : verify the incoming connection is the currently enlisted one?
-		TestingJtaPlatformImpl.synchronizationRegistry().putResource( CONNECTION_KEY, null );
+		try {
+			TestingJtaPlatformImpl.synchronizationRegistry().putResource( CONNECTION_KEY, null );
+		}
+		catch ( Exception e ) {
+			System.err.println( "!!!Error trying to reset synchronization registry!!!" );
+		}
 		try {
 			delegate.closeConnection( connection );
 		}