Re: PGPoolingDataSource problem. - Mailing list pgsql-jdbc

On 06/08/11 18:36, Benjamin.Galaviz@LSGSkyChefs.com wrote:
> I am using the JDBC3 PGPoolingDataSource to create a pool of 5 connections
> (for test) to my database.
>
> public class DatabasePool {
>

Improved and corrected (albeit untested) versions of your code below -
but please read my comment at the end of this message on why you don't
want to reinvent the wheel.

public class ConnectionFactory {
     private static PGPoolingDataSource ds;

     private ConnectionFactory() {
         // enforce singleton
     }

     private static synchronized DataSource getDataSource() throws
SQLException {
         if (ds == null){
             ds = new PGPoolingDataSource();
             ds.setDataSourceName("DataSource");
             ds.setServerName("XX.XX.XX.XX");
             ds.setDatabaseName("dbname");
             ds.setUser("user");
             ds.setPassword("password");
             ds.setMaxConnections(5);
         }

         return ds;
     }

     public static Connection getConnection() throws SQLException {
         return getDataSource.getConnection();
     }

     public static void releaseConnection(final Connection connection) {
         if (connection != null) {
             try {
                 connection.close();
             } catch (SQLException exception) {
                 // log warning ...
             }
         }
     }
}
>
> I get a leaked connections when I grab more than one connection from the
> pool at a time.
>
> Public void insertData(){
>
> Private String getValue(String XX){
>

public void insertData(final String sql) throws SQLException {
     Connection connection = null;

     try {
         connection = ConnectionFactory.getConnection();

         PreparedStatement ps = connection.preparedStatement(sql);
         ps.setString(1, "foo");
         ps.executeUpdate();
         ps.close();
     } finally{
         ConnectionFactory.releaseConnection(connection);
     }
}

public String getValue(final String sql, final String foo) throws
SQLException {
     String value = null;

     Connection connection = null;

     try {
         connection = ConnectionFactory.getConnection();

         PreparedStatement ps = connection.preparedStatement(sql);

         ResultSet rs = ps.executeQuery();

         if (rs.next()) {
             value = rs.getString(1);
         }

         rs.close();

         ps.close();
     } finally{
         ConnectionFactory.releaseConnection(connection);
     }

     return value;
}

However, you'd be much better served by using a framework that hides
the verboseness of JDBC. The Spring framework has an excellent wrapper
for JDBC that also supports pooling, and deals well with the various
niggles that such a wrapper exposes.

Chris




Chris Wareham
Senior Software Engineer
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