Byte Data Type

Hadoop serialization and Writable Interface (i) introduced the Hadoop serialization, the Hadoop writable interface and how to customize your own writable class, and in this article we continue to introduce the Hadoop writable class, 　　This time we are concerned about the length of bytes occupied after the writable instance was serialized, and the composition of the sequence of bytes after the writable instance was serialized. Why to consider the byte length of the writable class large data program ...

Either in the pitiful free database space or large e-commerce sites, reasonable design table structure, make full use of space is very necessary. This requires that we have a full understanding of the commonly used MySQL data types for database systems. Now I will write down my little experience to share with you. The numeric type of the MySQL data type The numeric type is divided into three categories according to my classification: integer classes, decimal classes, and numeric classes. My so-called "digital class" refers to DECIMAL and NUMERIC, which are the same type. It is strictly speaking not ...

1. Boxing, unpacking or aliases many of the introduction of C #. NET learning experience books on the introduction of the int-> Int32 is a boxing process, the reverse is the process of unpacking. This is true of many other variable types, such as short <-> int16,long <->int64. For the average programmer, it is not necessary to understand this process, because these boxes and unboxing actions can be automatically completed, do not need to write code to intervene. But we need to remember that ...

Cloud storage is a concept that extends and develops in the concept of cloud computing (Cloud Computing). Its goal is to combine application software with storage devices to transform storage devices into storage services through application software. In short, cloud storage is not storage, it's a service. This service can provide virtual storage on demand on the network, also known as data storage as a service (Storage, DaaS). The customer pays for the storage capacity that is actually required to purchase. Any reference to the amount of fixed capacity added ...

Base64 is one of the most commonly used encodings, such as the development of passing parameters, the <img/> tags in modern browsers to render pictures directly through Base64 strings, and for messages and so on.　　The BASE64 encoding is defined in RFC2045, which is defined as: Base64 content transfer encoding is designed to describe the 8-bit byte of any sequence as a form that is not easily recognized directly by the person. We know that any data is stored in binary form on the computer. One byte is 8 bits, one character is stored in the computer ...

This paper is an excerpt from the book "The Authoritative Guide to Hadoop", published by Tsinghua University Press, which is the author of Tom White, the School of Data Science and engineering, East China Normal University. This book begins with the origins of Hadoop, and integrates theory and practice to introduce Hadoop as an ideal tool for high-performance processing of massive datasets. The book consists of 16 chapters, 3 appendices, covering topics including: Haddoop;mapreduce;hadoop Distributed file system; Hadoop I/O, MapReduce application Open ...

MapReduce: Simple data processing on large cluster

In the past two years, the big data has been widely discussed by the public, and even become the selling point of many business marketing. Undoubtedly, the development and popularization of intelligent devices make the mass data collection possible. But the big data is not pure "data big", it contains a kind of calculation and thinking way change, want to exert big data insight, still face the challenge of collecting, managing, analyzing data. How can these obstacles be broken? How can large data be used in the future to create greater value? These questions are worth our cool judgment in the heat of the big data. April 26, Tsinghua University set up "Tsinghua ...

This article is my second time reading Hadoop 0.20.2 notes, encountered many problems in the reading process, and ultimately through a variety of ways to solve most of the. 　　Hadoop the whole system is well designed, the source code is worth learning distributed students read, will be all notes one by one post, hope to facilitate reading Hadoop source code, less detours. 1 serialization core Technology The objectwritable in 0.20.2 version Hadoop supports the following types of data format serialization: Data type examples say ...

It can be said that big data is one of the hottest trends in the IT industry today, and it has spawned a new batch of technologies to deal with big data. And new technologies have brought the latest buzz words: acronyms, professional terms, and product names. Even the phrase "big data" itself makes a person dizzy. When many people hear "big data", they think it means "a lot of data", and the meaning of large data does not only involve the amount of data. Here are a few popular words that we think you should be familiar with, sorted alphabetically. ACID ...