coderplay

import java.util.Arrays;
import java.util.Random;

public class IntArrayIntersection {

  /*
   * O(N+M)
   */
  public static int[] intersectByLiteration(final int[] lhs, final int[] rhs) {
    // worst case size for the intersection array

coderplay

class Lock {}
class Danger {
  static {
    System.out.println("clinit begin...");
    try {Thread.sleep(2000);} catch (Exception e) {}
    synchronized (Lock.class) { System.out.println("clinit done!");}
  }
}
public class Hang {
  public static void main(String[] args) {

coderplay

SemanticAnalyzer主体流程

• 新建QueryBlock
• 预处理(语意分析)
• 获取MetaData
• 获取每个源table的相关结构
• 将视图替换, 重写, 并将其记入view别名
• 检查inputformat
• 保存alias->tab 至QB
• 为子查询获取meta
• 获取目标的相关结构, 目标有两种:表或本地目录

coderplay

import java.lang.reflect.Field;
import java.util.Random;
 
import sun.misc.Unsafe;
 
public class GroupVarInt {
 private final static int UINT24_MAX = ((2<<23) - 1);
	private final static int UINT16_MAX = ((2<<15) - 1);
	private final static int UINT8_MAX = ((2<<7) -1);
	private static final long BYTE_ARRAY_OFFSET;

coderplay

import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.RunnableFuture;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

coderplay

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>

#define NANOSECS_PER_SEC 1000000000

pthread_mutex_t lock;

coderplay

import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.LinkOption;
import java.nio.file.Paths;
import java.util.List;
import java.util.ArrayList;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveTask;
import java.io.IOException;

coderplay

Java应用中经常用ByteBuffer.allocateDirect()或者Unsafe.allocateMemory()分配一段内存。 MAT等内存查看器看不到native的内存, 所以需要借助gdb等工具来查看.

ByteBuffer bb = ByteBuffer.allocateDirect(capacity)
                              .order(ByteOrder.nativeOrder());

这种ByteBuffer可以得到它的起始内存地址

coderplay

Master start

1. aggregator handler
2. start a netty master server - to receive messages from workers
3. start a netty master client - to send messages to workers
4. create vertex/edge input splits, write splits to zk in parallel
5. while () do coordinatesuperstep()

Worker start

1. partitioner
2. start a worker server

coderplay

tajo> select count(1) from supplier;
Progress: 50%, response time: 1.033 sec
Progress: 100%, response time: 1.481 sec
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/mzhou/tajo/tajo-0.2.0-SNAPSHOT/lib/slf4j-log4j12-1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/mzhou/hadoop/hadoop-2.0.5-alpha/share/hadoop/common/lib/slf4j-log4j12-1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
2013-12-05 20:28:33,330 WARN  storage.AbstractStorageManager (AbstractStorageManager.java:<init>(85)) - does not support block metadata. ('dfs.datanode.hdfs-blocks-metadata.enabled')
final state: QUERY_SUCCEEDED, init time: 0.135 sec, response time: 1.481 sec
result: hdfs://172.16.19.32:8020/tajo-mzhou/staging/q_1386302792972_0002/RESULT, 1 rows (8 B)