<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[坚定]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/iteye_20587</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; iteye_20587]]></copyright><item><title><![CDATA[Storm基本概念]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82610674</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82610674</guid><author>iteye_20587</author><pubDate>Fri, 05 Dec 2014 16:49:45 +0800</pubDate><description><![CDATA[

2.1 Storm基本概念

在运行一个Storm任务之前，需要了解一些概念：

Topologies
Streams
Spouts
Bolts
Stream groupings
Reliability
Tasks
Workers
Configuration

 
Storm集群和Hadoop集群表面上看很类似。但是Hadoop上运行的是MapReduce jobs，...]]></description><category></category></item><item><title><![CDATA[linux 日期转换]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580474</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580474</guid><author>iteye_20587</author><pubDate>Fri, 23 May 2014 18:27:22 +0800</pubDate><description><![CDATA[
date -d '1970-01-01 UTC 946684800 seconds' +&quot;%Y-%m-%d %T %z&quot;
 
 start_time=`date -d &quot;1970-01-01 UTC  $date_start seconds&quot; +&quot;%Y-%m-%d %H:%M:%S&quot;`;
]]></description><category></category></item><item><title><![CDATA[crontab与环境变量]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580401</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580401</guid><author>iteye_20587</author><pubDate>Fri, 23 May 2014 11:15:10 +0800</pubDate><description><![CDATA[2. crontab与环境变量不要假定cron知道所需要的特殊环境，它其实并不知道。所以你要保证在shelll脚本中提供所有必要的路径和环境变量，除了一些自动设置的全局变量。所以注意如下3点：1）脚本中涉及文件路径时写全局路径；2）脚本执行要用到java或其他环境变量时，通过source命令引入环境变量，如：cat start_cbp.sh#!/bin/shsource /etc/profilee...]]></description><category></category></item><item><title><![CDATA[mysql小技巧]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580328</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580328</guid><author>iteye_20587</author><pubDate>Thu, 22 May 2014 14:21:26 +0800</pubDate><description><![CDATA[
order by null
用途是强制对查询结果禁用排序。通过explain检查查询语句时候，如果看到Extra列中有Using filesort，这是对性能有一定影响的，特别是使用了group by时，就算你没有显示的指定order by，mysql会默认按照分组字段进行排序。某些情况下是没有必要使用排序的，例如在处理表报数据的时候（把原始表数据统计后插入到一个用于报表查询的表），则完全可...]]></description><category></category></item><item><title><![CDATA[hive sql 优化]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580327</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580327</guid><author>iteye_20587</author><pubDate>Thu, 22 May 2014 14:21:17 +0800</pubDate><description><![CDATA[
Hive是将符合SQL语法的字符串解析生成可以在Hadoop上执行的MapReduce的工具。使用Hive尽量按照分布式计算的一些特点来设计sql，和传统关系型数据库有区别，
所以需要去掉原有关系型数据库下开发的一些固有思维。
 
基本原则：
1. 尽量尽早地过滤数据，减少每个阶段的数据量,对于分区表要加分区，同时只选择需要使用到的字段
select ... from A
join...]]></description><category></category></item><item><title><![CDATA[oracle 相关]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580216</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580216</guid><author>iteye_20587</author><pubDate>Wed, 21 May 2014 15:21:03 +0800</pubDate><description><![CDATA[
找表
select * from all_tables where table_name like '%NGINX_LOG_REPORT%'
 

=========任务运行===============

 
---任务列表
select spend_time/60,t.* from SPEND_TIME t
--where lower(t_name)=lower('P_TADU...]]></description><category></category></item><item><title><![CDATA[hive查询相关]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580214</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580214</guid><author>iteye_20587</author><pubDate>Wed, 21 May 2014 15:12:57 +0800</pubDate><description><![CDATA[
一、嵌套查询统计数量去重问题
描述：如果子查询中对统计的字段已经去重，外面一层就不能同时有distinct（目标统计字段）和group by操作，否则查询结果不是统计的数量而是统计的字段数据。
如：
select

platform_id, count(distinct user_id) uv_count


from

(

select

platform_id, user...]]></description><category></category></item><item><title><![CDATA[shell 时间处理]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580213</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580213</guid><author>iteye_20587</author><pubDate>Wed, 21 May 2014 15:11:57 +0800</pubDate><description><![CDATA[
start_dt=&quot;20130101&quot;;
end_dt=&quot;20131231&quot;;
for ((i=0;i&amp;lt;= $(($(date +%s -d &quot;$end_dt&quot;) - $(date +%s -d &quot;$start_dt&quot;)))/86400 |bc ;i++)) ;do


report_day=$(date -d &quot;$start_dt +$i day&quot; +%Y%m%d)

ec..]]></description><category></category></item><item><title><![CDATA[hadoo安装常见问题]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580211</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580211</guid><author>iteye_20587</author><pubDate>Wed, 21 May 2014 15:10:48 +0800</pubDate><description><![CDATA[
遇到问题以后先查看日志，以下是常见的错误情况及解决方法，希望对大家有所帮助。
1、启动hadoop时没有NameNode的可能原因：
（1） NameNode没有格式化
（2） 环境变量配置错误
（3） Ip和hostname绑定失败
2、地址占用
报错：org.apache.hadoop.hdfs.server.namenode.NameNode: Address already ...]]></description><category></category></item><item><title><![CDATA[防止误删文件无法恢复]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82580209</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82580209</guid><author>iteye_20587</author><pubDate>Wed, 21 May 2014 14:50:26 +0800</pubDate><description><![CDATA[
rm -rf 慎用
命令敲得多了，常在河边走，难免会湿鞋
rm 特别是rm -rf之前，小心，三思，提前做好备份
为了避免因为误操作而导致文件无法恢复的问题，特在hadoop集群的每台机器上添加了&quot;回收站&quot;机制。
首先,在~下 .bashrc（或者.bash_profile）加入
mkdir -p /ty/.trash
alias rm=trash
alias r=trash
...]]></description><category></category></item><item><title><![CDATA[plsql相关]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/82213024</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/82213024</guid><author>iteye_20587</author><pubDate>Fri, 02 Dec 2011 16:43:35 +0800</pubDate><description><![CDATA[plsql中 perferences 下的 user interface 下的editor 中的 autoreplace。在definition file中指定自己定义的文件的路径就可以了。
 
f = FROM s* = SELECT COUNT(*) FROM w = T WHERE st = SELECT T.*,T.ROWID FROM s = SELECT * FROM l = LI...]]></description><category></category></item><item><title><![CDATA[windows-xp-home-to-professional]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81891805</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81891805</guid><author>iteye_20587</author><pubDate>Mon, 12 Jul 2010 11:07:29 +0800</pubDate><description><![CDATA[http://www.mydigitallife.info/2008/06/13/convert-and-upgrade-windows-xp-home-to-professional-without-reinstalling/ 
 
1 依次点击：开始-&amp;gt;运行，输入regedit 
2 找到 HKEY_LOCAL_MACHINE/SYSTEM/ControlSet00X/Contro...]]></description><category></category></item><item><title><![CDATA[oracle相关]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81891235</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81891235</guid><author>iteye_20587</author><pubDate>Fri, 09 Jul 2010 10:34:33 +0800</pubDate><description><![CDATA[oracle 建立数据库1、怎么查看我总共建了几个库？答：一个叫install的文件夹下的portlist.ini2、开始菜单里的oracle文件夹的配置和移植工具Database Configuration Assistant 菜单3、建好了后再去看那个.ini文件，里面应该有你这个库的管理配置页面的端口了（http）4、开始里的oracle菜单Net Configuration Assista...]]></description><category></category></item><item><title><![CDATA[Ue使用技巧]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81889021</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81889021</guid><author>iteye_20587</author><pubDate>Wed, 30 Jun 2010 17:56:04 +0800</pubDate><description><![CDATA[
Ctrl+b     选中括号内的
F3           查找下一个相同的选中的内容
ctrl+tab  多个文件切换
ctrl+g     到所在的行
ctrl+f2     建立标签，然后alt+f2切换
ctrl+e      删除整行
F7           插入系统时间
...]]></description><category></category></item><item><title><![CDATA[查看端口占用]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81863493</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81863493</guid><author>iteye_20587</author><pubDate>Tue, 25 May 2010 16:21:42 +0800</pubDate><description><![CDATA[假如我们需要确定谁占用了我们的9050端口
1、Windows平台在windows命令行窗口下执行：

C:\&amp;gt;netstat -aon|findstr &quot;9050&quot;

TCP    127.0.0.1:9050         0.0.0.0:0              LISTENING       2016

看到了吗，端口被进程号为2016的进程占用，继续执行下面命令...]]></description><category></category></item><item><title><![CDATA[j2me写文件]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81856867</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81856867</guid><author>iteye_20587</author><pubDate>Thu, 29 Apr 2010 10:54:21 +0800</pubDate><description><![CDATA[FileConnection fc;
		try {
			String elem = null;
			Enumeration e = FileSystemRegistry.listRoots();
			while (e.hasMoreElements()) {
				elem = e.nextElement().toString();
			}
			System.out.p...]]></description><category></category></item><item><title><![CDATA[java 文件(临时文件)操作]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81850376</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81850376</guid><author>iteye_20587</author><pubDate>Fri, 09 Apr 2010 11:12:32 +0800</pubDate><description><![CDATA[	public static void doFile(String fileName) {
		try {
			File file = new File(fileName);
			if (file.exists()) {
				file.createNewFile();
			}
			if (!file.getParentFile().exists()) {
				file...]]></description><category></category></item><item><title><![CDATA[short 数组和int转换成byte数组]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81849930</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81849930</guid><author>iteye_20587</author><pubDate>Thu, 08 Apr 2010 14:18:49 +0800</pubDate><description><![CDATA[short［］转换成byte［］

byte a[] = new byte[out.length * 2];
		for (int i = 0; i &amp;lt; out.length; i++) {
			a[i * 2] = (byte) (out[i] &amp;amp; 0xFF);
			a[i * 2 + 1] = (byte) ((out[i] &amp;gt;&amp;gt; 8) &amp;amp; 0x...]]></description><category></category></item><item><title><![CDATA[Java与其他语言数据类型之间的转换方法]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81848833</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81848833</guid><author>iteye_20587</author><pubDate>Wed, 07 Apr 2010 11:33:13 +0800</pubDate><description><![CDATA[public final static byte[] getBytes(short s, boolean asc) {
    byte[] buf = new byte[2];
    if (asc)
      for (int i = buf.length - 1; i &amp;gt;= 0; i--) {
        buf[i] = (byte) (s &amp;amp; 0x00ff)...]]></description><category></category></item><item><title><![CDATA[wav格式详解]]></title><link>https://blog.youkuaiyun.com/iteye_20587/article/details/81848832</link><guid>https://blog.youkuaiyun.com/iteye_20587/article/details/81848832</guid><author>iteye_20587</author><pubDate>Wed, 07 Apr 2010 11:30:10 +0800</pubDate><description><![CDATA[一、综述    WAVE文件作为多媒体中使用的声波文件格式之一，它是以RIFF格式为标准的。RIFF是英文Resource Interchange File Format的缩写，每个WAVE文件的头四个字节便是“RIFF”。    WAVE文件是由若干个Chunk组成的。按照在文件中的出现位置包括：RIFF WAVEChunk, Format Chunk, Fact Chunk(可选), Data...]]></description><category></category></item></channel></rss>