Querying the Execution Progress and Status of an SQL Statement Using JDBC

Description

This section describes how to use JDBC to connect to HetuEngine with the username and password, and assemble and send the SQL statements to HetuEngine for execution.

import io.xxx.jdbc.xxxResultSet;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Properties;
import java.util.Timer;
import java.util.TimerTask;

public class JDBCExampleStatementProgressPercentage{

    private static Properties properties = new Properties();
    public static Connection connection = null;
    public static ResultSet result = null;
    public static PreparedStatement statement = null;
    private static void init() throws ClassNotFoundException {
        // Hard-coded password or plaintext password in code poses significant security risks. Encrypt and store them in configuration files or environment variables and decrypt them when needed.
        // The password is stored in environment variables for identity authentication. Before running this example, set the environment variable HETUENGINE_PASSWORD.
        properties.setProperty("user", "YourUserName");
        String password = System.getenv("HETUENGINE_PASSWORD");
        properties.setProperty("password", password);
        Class.forName("io.xxx.jdbc.xxxDriver");
    }

    /**
      * Program entry
      *
      * @param args no need program parameter
      */
    public static void main(String[] args) {
        String url = "jdbc:xxx://192.168.81.37:2181,192.168.195.232:2181,192.168.169.84:2181/hive/default?serviceDiscoveryMode=hsbroker";
        try {
            init();
            String sql = "show tables";
            connection = DriverManager.getConnection(url, properties);
            statement = connection.prepareStatement(sql.trim());
            result = statement.executeQuery();

           xxxResultSet rs = (xxxResultSet) result;
            new Thread() {
                public void run() {
                    Timer timer = new Timer();
                    //The SQL statement is executed after 3 seconds and is executed every 2 seconds
                    timer.schedule(new TimerTask() {
                        @Override
                        public void run() {
                            double statementProgressPercentage = rs.getProgressPercentage().orElse(0.0);
                            System.out.println("The Current Query Progress Percentage is " + statementProgressPercentage*100 + "%");
                            if("FINISHED".equals(rs.getStatementStatus().orElse(""))) {
                                System.out.println("The Current Query Progress Percentage is 100%");
                                timer.cancel();
                                Thread.currentThread().interrupt();
                            }
                        }
                    }, 3000, 2000);
                }
            }.start();

            ResultSetMetaData resultMetaData = result.getMetaData();
            int colNum = resultMetaData.getColumnCount();
            for (int j = 1; j <= colNum; j++) {
                try {
                    System.out.print(resultMetaData.getColumnLabel(j) + "\t");
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }

            while (result.next()) {
                for (int j = 1; j <= colNum; j++) {
                    System.out.print(result.getString(j) + "\t");
                }
                System.out.println();
            }
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            if (result != null) {
                try {
                    result.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (statement != null) {
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (connection != null) {
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

Table 1 describes the parameters in the preceding code.