[HIVE-4762] HMS cannot handle concurrent requests

• Type: Sub-task
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.11.0
• Fix Version/s: 0.12.0
• Assignee: Brock Noland
• Reporter: Brock Noland
• Created: 19/Jun/13 20:52
• Updated: 15/Oct/13 23:30
• Resolved: 20/Jun/13 16:51

Description

It appears our use of DataNucleaus is not correct or perhaps there is a bug in the ancient version of DN we are using. On startup having multiple threads performing "show tables" results in failures. Additionally concurrent DML will fail event after startup. I used the program below to demonstrate this.

package org.apache.hadoop.hive.ql;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.apache.hive.jdbc.HiveDriver;

public class MultiThreadTest {

  public static class QueryRunner implements Runnable {
    int id;
    double averageElapsedTime;
    Connection connection;
    Statement statement;
    QueryRunner(int id) {
      this.id = id;
    }

    @Override
    public void run() {
      long count = 0;
      double elapsedTime = 0;
      try {
        connection = DriverManager.getConnection("jdbc:hive2://localhost:10000/default", "brock", "password");
        statement = connection.createStatement();
//        statement.execute("DROP TABLE IF EXISTS t" + id);
        for (int i = 0; i < 10; i++) {
//          statement.execute("CREATE TABLE t" + id + " (key int)");
          long start = System.currentTimeMillis();
//          statement.execute("DROP TABLE t" + id);
          statement.execute("SHOW TABLES");
          elapsedTime += System.currentTimeMillis() - start;
          count++;
        }
        if(statement != null) {
          statement.close();
        }
        if(connection != null) {
          connection.close();
        }
      } catch (Exception e) {
        e.printStackTrace();
      } finally {
        if(count > 0) {
          averageElapsedTime = elapsedTime / (double)count;
        }
      }
    }
  }

  public static void main(String[] args) throws Exception {
    int numThreads = 50;
    Class.forName(HiveDriver.class.getName());
    ExecutorService executor = Executors.newFixedThreadPool(numThreads);
    QueryRunner[] queryRunners = new QueryRunner[numThreads];
    for (int i = 0; i < numThreads; i++) {
      queryRunners[i] = new QueryRunner(i);
      executor.execute(queryRunners[i]);
    }
    executor.shutdown();
    while(!executor.isTerminated()) {
      System.out.println("Waiting...");
      Thread.sleep(1000L);
    }
    for (int i = 0; i < numThreads; i++) {
      System.out.println(Math.round(queryRunners[i].averageElapsedTime));
    }
  }
}

Issue Links

• is related to: HIVE-5457 Concurrent calls to getTable() result in: MetaException: org.datanucleus.exceptions.NucleusException: Invalid index 1 for DataStoreMapping. NucleusException: Invalid index 1 for DataStoreMapping
• relates to: HIVE-3521 Concurrent metastore calls provoke Datanucleus IllegalStateException: "Table object has not been been initialised"