Combine small files to sequence file or avro files are a good method to feed hadoop. Small files in hadoop will take more namenode memory resource. SequenceFileInputFormat 是一种Key value 格式的文件格式. Key和Value的类型可以自己实现其序列化和反序列化内容. SequenceFile示例内容: 其默认的key…

write & read a sequence file write & read a sequence file import java.io.IOException; import org.apache.hadoop.io.SequenceFile; import org.apache.hadoop.io.SequenceFile.Writer; import org.apache.hadoop.io.SequenceFile.Reader; import org.apache.had…

Hadoop除了可以让开发人员自行编写map函数和reduce函数,还提供一些常用函数(mapper.reducer和partitioner)的类库,这些类位于 org.apache.hadoop.mapred.lib 包内,在1.2.1版,该包包含一个接口和若干类.在org.apache.hadoop.mapreduce.lib 包内也存在相关类库,且有部分重复.mapred包内部是旧API,mapreduce包是重构之后的新API,但两者都可以使用. 接口如下: InputSampler.S…

基本环境:官方社区版MySQL 5.7.19 一.了解Binary Log结构 1.1.High-Level Binary Log Structure and Contents • Binlog包括binary log files和index file• 每个binary log文件的前4字节是Magic Number,紧接着是一组描述数据修改的Events • The magic number bytes are 0xfe 0x62 0x69 0x6e = 0xfe 'b''i''n' • 每…

Files and Directories Introduction     In the previous chapter we coveredthe basic functions that perform I/O. The discussion centered on I/O for regular files-opening a file, and reading or writing a file. We'll now look at additionalfeatures of the…

Given a list of directory info including directory path, and all the files with contents in this directory, you need to find out all the groups of duplicate files in the file system in terms of their paths. A group of duplicate files consists of at l…

前言 上传文件应该是很常见必不可少的一个操作,网上也有很多提供的上传控件.今天遇到一个问题:input控件file无法进行异步无刷新上传.真真的感到别扭.所以就尝试这去处理了一下.主要分三个部分:上传类的封装,html input控件file处理和后台controller的调用. 上传封装类: 此类主要两个功能,一些简单的筛选和文件重命名操作. 文件的筛选包括: 文件类型,文件大小 重命名: 其中默认为不进行重命名操作,其中重命名默认为时间字符串DateTime.Now.ToString("yy…

小型文件数据库 (a file database for small apps) SharpFileDB For english version of this article, please click here. 我并不擅长数据库,如有不当之处,请多多指教. 本文参考了(http://www.cnblogs.com/gaochundong/archive/2013/04/24/csharp_file_database.html),在此表示感谢! 目标(Goal) 我决定做一个以支持小型应用(…

SharpFileDB - a file database for small apps 本文中文版在此处. I'm not an expert of database. Please feel free to corect my mistakes. This article (http://www.cnblogs.com/gaochundong/archive/2013/04/24/csharp_file_database.html) helpes a lot. Thank you! 目标(G…

转载:https://www.linux.com/learn/linux-career-center/44184-the-kernel-newbie-corner-kernel-debugging-with-proc-qsequenceq-files-part-3 Finally, after two installments of the basics of debugging with sequence files, we're going to finish off by demonstr…