Boolean Object

There is a concept of an abstract file system in Hadoop that has several different subclass implementations, one of which is the HDFS represented by the Distributedfilesystem class. In the 1.x version of Hadoop, HDFS has a namenode single point of failure, and it is designed for streaming data access to large files and is not suitable for random reads and writes to a large number of small files. This article will explore the use of other storage systems, such as OpenStack Swift object storage, as Ha ...

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 ...

Hadoop RPC communication is different from other systems RPC communication, the author for the use of Hadoop features, specifically designed a set of RPC framework, the framework of personal feeling is still a little complicated. So I'm going to split into client-side and Server service-side 2 modules for analysis. If you have a good understanding of RPC's entire process, you must be able to understand it very quickly for Hadoop RPC. OK, let's cut to the chase. The related code for the RPC of Hadoop is ORG.APAC ...

Blog Description: 1, research version hbase 0.94.12;2, posted source code may be cut, only to retain the key code. 　　Discusses the HBase write data process from the client and server two aspects. One, client-side 1, write data API write data is mainly htable and batch write two API, the source code is as follows://write the API public void to put ("final") throws IO ...

Java Iterable interface and the Iterator interface. The class that implements the Iterable interface is iterable; the class that implements the Iterator interface is an iterator.

Due to the requirements of the project, it is necessary to submit yarn MapReduce computing tasks through Java programs. 　　Unlike the general task of submitting MapReduce through jar packages, a small change is required to submit mapreduce tasks through the program, as detailed in the following code. 　　The following is MapReduce main program, there are a few points to mention: 1, in the program, I read the file into the format set to Wholefileinputformat, that is, not to the file segmentation. 2, in order to control the treatment of reduce ...

Iterator and iterable objects in Java. Let's take a look at the difference between these two objects and how to implement the for each loop in a custom class.

The Jvax (JSON Verification and conversion/transformation) system processes all incoming requests before the cloud service receives an incoming request. Jvax is designed to handle various http://www.aliyun.com/zixun/aggregation/17253.html "> common problems" that occur when using JSON as a payload for API requests. This paper proposes a solution ...

I. Build HADOOP development environment The various code that we have written in our work is run in the server, and the HDFS operation code is no exception. During the development phase, we used eclipse under Windows as the development environment to access the HDFs running in the virtual machine. That is, accessing HDFs in remote Linux through Java code in local eclipse. To access the HDFS in the client computer using Java code from the host, you need to ensure the following: (1) Ensure host and client ...

The previous article describes the use of the "blob storage service in Windows http://www.aliyun.com/zixun/aggregation/13357.html" >azure Storage Service "to store files, and this article describes The Windows Azure storage service is another storage service--"table storage service. The Table storage Service is a NoS provided on Windows Azure ...