Main.java

package pgamemoryleak;

import java.io.BufferedReader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import oracle.jdbc.pool.OracleDataSource;

public class Main {

	public static void main(String[] args) throws IOException, SQLException, InterruptedException {

		final OracleDataSource oracleDataSource = readConfig();
		try (Connection connection = oracleDataSource.getConnection()) {

			while (true) {
				final ResultSet resultSetMyPGA;
				try (Statement statement = connection.createStatement();
						ResultSet resultSetTopSQL = statement.executeQuery(QUERY_TOP_SQL)) {

					// ignore the result - calling the query is enough to cause memory leak
				}
				try (Statement statement = connection.createStatement()) {
					resultSetMyPGA = statement.executeQuery(QUERY_MY_PGA);
					resultSetMyPGA.next();
					final int pgaUsage = resultSetMyPGA.getInt(2);
					System.out.println("PGA usage: " + pgaUsage);
				}

				Thread.sleep(1000);
			}
		}
	}

	private static final String QUERY_TOP_SQL =
			"select a1.sql_id,"
			+ "       a1.elapsed_time,"
			+ "       a1.cpu_time,"
			+ "       a1.sql_fulltext sql_fulltext,"
			+ "       a1.disk_reads,"
			+ "       a1.direct_writes,"
			+ "       a1.executions,"
			+ "       to_timestamp(a1.first_load_time, 'yyyy-mm-dd/hh24:mi:ss') first_load_time,"
			+ "       a1.last_load_time,"
			+ "       a1.parse_calls,"
			+ "       a1.buffer_gets,"
			+ "       a1.rows_processed,"
			+ "       a1.user_io_wait_time,"
			+ "       a1.cluster_wait_time,"
			+ "       a1.concurrency_wait_time,"
			+ "       a1.application_wait_time,"
			+ "       a1.parsing_schema_name"
			+ " from v$sql a1";

	private static final String QUERY_MY_PGA = "select machine, round(pga_used_mem / (1024 * 1024),2) pga_used_mb"
			+ " from v$session"
			+ "         join v$process on v$session.paddr = v$process.addr"
			+ " where sid = ("
			+ "    select sid from v$mystat where rownum=1"
			+ "    )"
			+ " order by machine desc";


	private static OracleDataSource readConfig() throws IOException, SQLException {
		final Path configFile = Paths.get("config", "config.properties");
		try (BufferedReader reader = Files.newBufferedReader(configFile)) {
			Properties config = new Properties();
			config.load(reader);

			String host = config.getProperty("host");
			String port = config.getProperty("port");
			String service = config.getProperty("service");
			String login = config.getProperty("login");
			String password = config.getProperty("password");

			System.out.println("Config read:"
					+ " host:" + host
					+ " port:" + port
					+ " service:" + service
					+ " login:" + login
					+ " password:" + password);

			final OracleDataSource oracleDataSource = new OracleDataSource();
			oracleDataSource.setDriverType("thin");
			oracleDataSource.setServerName(config.getProperty("host"));
			oracleDataSource.setPortNumber(Integer.parseInt(config.getProperty("port")));
			oracleDataSource.setServiceName(config.getProperty("service"));
			oracleDataSource.setUser(config.getProperty("login"));
			oracleDataSource.setPassword(config.getProperty("password"));

			return oracleDataSource;
		}
	}
}