Puedo insertar 2000 registros en 3.5 segundos desde mi computadora, GAE toma 14.0 segundos para hacer lo mismo. No puedo ver cómo puedo hacer que el controlador de Google use la configuración rewriteBatchedStatements.

Aquí está mi código Java relevante:

package year2016.tax8949.database2;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.List;
import java.util.Properties;
import java.util.logging.Logger;

public class Form89492016TableInserter {

private static final Logger log 
    = Logger.getLogger( "Form89492016TableInserter" );

protected static final String USERNAME = "xxxx";

protected static final String PASSWORD = "xxxxx";

protected static final String INSTANCE_CONNECTION_NAME 
    = "xxxx:us-central1:xxxxx";

protected static final String DB_NAME = "xxxxxx";

protected static final String IP_ADDRESS = "xxx.1xx.2xx.4x";

protected static final String SQL_INSERT 
    = "INSERT into Forms1099B ( orderNumber,acctId,qty,secDesc,dateAcq,dateSold,salesPrice,cost,basisAdj,washAdj,nomineeAdj,otherAdj,term,basisRep,rep1099B,tranType,dateAcqVar,covered,symbol,expired ) VALUES ( ?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,? )";


// Whether connecting from Google App Engine
private boolean fromGAE = false;

// JDBC connection
private Connection conn = null;

public Form89492016TableInserter( boolean fromGAE ) {
    this.fromGAE = fromGAE;
}

public void insertBatch( List<Forms1099BRecordBean> records ) {

    int batchSize = 500;

    insertBatchUsingSize( records, batchSize );
}

public void insertBatchUsingSize( List<Forms1099BRecordBean> records, 
                                  int batchSize ) {

    try {

        initializeConnection( );

        doInsertions( records, batchSize );

        closeConnection( );

    }
    catch( SQLException e ) {
        log.severe( e.getMessage( ) );
    }

}

public void closeConnection( ) throws SQLException {

    if ( conn != null ) { 
        conn.close( ); 
    } 

}

public void initializeConnection( ) throws SQLException {

    String driverName 
        = ( fromGAE ) ? "com.mysql.jdbc.GoogleDriver" : 
                        "com.mysql.jdbc.Driver";

    try {
        Class.forName( driverName );
    }
    catch( ClassNotFoundException e ) {
        log.severe( e.getMessage( ) );
        return;
    }

    if ( fromGAE ) {

        String connectionString 
            = String.format( 
                 "jdbc:google:mysql://%s/%s?user=root&password=%s", 
                 INSTANCE_CONNECTION_NAME, 
                 DB_NAME, 
                 PASSWORD );

        conn = DriverManager.getConnection( connectionString );

    }
    else {

        String url = String.format( "jdbc:mysql://%s:3306/%s",
                                    IP_ADDRESS,
                                    DB_NAME );

        Properties props = new Properties();
        props.setProperty( "user", USERNAME );
        props.setProperty( "password", PASSWORD );
        props.setProperty( "rewriteBatchedStatements", "true" );

        conn = DriverManager.getConnection( url, props );    

    }

}

private void doInsertions( List<Forms1099BRecordBean> records,
                           int batchSize ) throws SQLException {

    try ( PreparedStatement stmt = conn.prepareStatement( SQL_INSERT ) ) {

        for (int i = 0; i < records.size( ); i++) {

            Forms1099BRecordBean item = records.get( i );

            stmt.setString( 1, item.getOrderNumber() ); 
            stmt.setString( 2, item.getAcctId() ); 
            stmt.setString( 3, item.getQty() ); 
            stmt.setString( 4, item.getSecDesc() ); 
            stmt.setDate( 5, item.getDateAcq() ); 
            stmt.setDate( 6, item.getDateSold() ); 
            stmt.setBigDecimal( 7, item.getSalesPrice() ); 
            stmt.setBigDecimal( 8, item.getCost() ); 
            stmt.setBigDecimal( 9, item.getBasisAdj() ); 
            stmt.setBigDecimal( 10, item.getWashAdj() ); 
            stmt.setBigDecimal( 11, item.getNomineeAdj() ); 
            stmt.setBigDecimal( 12, item.getOtherAdj() ); 
            stmt.setString( 13, item.getTerm() ); 
            stmt.setString( 14, item.getBasisRep() ); 
            stmt.setString( 15, item.getRep1099B() ); 
            stmt.setString( 16, item.getTranType() ); 
            stmt.setString( 17, item.getDateAcqVar() ); 
            stmt.setString( 18, item.getCovered() ); 
            stmt.setString( 19, item.getSymbol() ); 
            stmt.setString( 20, item.getExpired() ); 

            stmt.addBatch( );

            // Execute every N items.
            if ( (i + 1) % batchSize == 0 ) {
                stmt.executeBatch( );     
            }

        }

        stmt.executeBatch( );

    }

}

}