mapreduce concepts

Directory address for this book Note: http://www.cnblogs.com/mdyang/archive/2011/06/29/data-intensive-text-prcessing-with-mapreduce-contents.html2.3 execution framework The greatest thing about mapreduce is that it separates parallel algorithm writing.WhatAndHow(You only need to write a program without worrying about how to execute it)The execution framework makes great contributions to this point: it handl

user data. After years of development, hadoop has become a popular data warehouse. Hammerbacher [68], talked about Facebook's building of business intelligence applications on Oracle databases, and later gave up, because he liked to use his own hadoop-based hive (now an open-source project ). Pig [114] is a platform built with hadoop for massive data analysis and can process structured data like semi-structured data. It was originally developed by Yahoo, but now it is an open-source project. If

3.1 local Aggregation) In a data-intensive distributed processing environment, interaction of intermediate results is an important aspect of synchronization from processes that generate them to processes that consume them at the end. In a cluster environment, except for the embarrassing parallel problem, data must be transmitted over the network. In addition, in hadoop, the intermediate result is first written to the local disk and then sent over the network. Because network and disk factors ar

　　Disclaimer: This article is reproduced from the blog Development team Blog, respect for the original work. This article is suitable for the study of distributed systems, as a background introduction to read. When it comes to distributed systems, you have to mention Google's Troika: Google Fs[1],mapreduce[2],bigtable[3].Although Google did not release the source code for the three products, he released detailed design papers for the three products. I

Directory address for this book Note: http://www.cnblogs.com/mdyang/archive/2011/06/29/data-intensive-text-prcessing-with-mapreduce-contents.html 2.5 Distributed File System HDFSTraditional large-scale data processing problems from the perspective of data placementPrevious focusProcessing. However, if there is no data, there is no way to deal with it.In traditional cluster architecture (such as HPC), computing and storage are two separate components..

MapReduce is one of the first steps to achieve Word Frequency Statistics, mapreduce Word Frequency Original podcast. If you need to reprint it, please indicate the source. Address: http://www.cnblogs.com/crawl/p/7687120.html Certificate ---------------------------------------------------------------------------------------------------------------------------------------------------------- A large number of

be used as a reducing function to return the sum of the values of the input data list.Put them together in the MapReduce.The MapReduce framework for Hadoop uses the above concepts to handle large-scale data information. The MapReduce program has two components: one implements the Mapper and the other implements the reducer. The mapper and reducer terms described

The previous blogs focused on Hadoop's storage HDFs, followed by a few blogs about Hadoop's computational framework MapReduce. This blog mainly explains the specific implementation process of the MapReduce framework, as well as the shuffle process, of course, this technical blog has been particularly numerous and written very good, I wrote a blog before the relevant reading, benefited. The references to som

mapreduce design goals/282.3 mapreduce programming model Overview/292.3.1 mapreduce Programming model Overview/292.3.2 mapreduce programming instance/312.4 hadoop basic architecture/322.4.1 HDFS architecture/332.4.2 hadoop mapreduce architecture/342.5 hadoop

line, and the previous part is key, after which it is value. If a "\ t" character is not there, the entire line is treated as a key.2. The sort and partition phases of the MapReduce Shuffler processThe mapper phase, in addition to user code, is most important for the shuffle process, which is the main place where MapReduce takes time and consumes resources because it involves operations such as Disk writes

3.2 pairs (pair) and stripes (stripe) A common practice of synchronization in mapreduce programs is to adapt data to the execution framework by building complex keys and values. We have covered this technology in the previous chapter, that is, "package" the total number and count into a composite value (for example, pair) from Mapper to combiner and then to Cer. Based on previous publications (54,94), this section describes two common design patterns

Directory address for this book Note: http://www.cnblogs.com/mdyang/archive/2011/06/29/data-intensive-text-prcessing-with-mapreduce-contents.html 3.4 secondary sorting Before intermediate results enter CER, mapreduce first sorts these intermediate results and then distributes them. This mechanism is very convenient for reduce operations that depend on the input sequence of intermediate results (in the o

In the process of local mapreduce development, it was found that the Eclipse console could not print the progress of the MapReduce job I wanted to see and some parameters before guessing it might have been a log4j problem, and had indeed reported Log4j's warning, and then tried it, It's really a log4j problem.Mainly because I did not configure Log4j.properties, the first new file in the SRC directory, and t

[Spring Data MongoDB] learning notes -- MapReduce, mongodb -- mapreduce Mongodb MapReduce mainly includes two methods: map and reduce. For example, assume that the following three records exist: { "_id" : ObjectId("4e5ff893c0277826074ec533"), "x" : [ "a", "b" ] }{ "_id" : ObjectId("4e5ff893c0277826074ec534"), "x" : [ "b", "c" ] }{ "_id" : ObjectId("4e5ff893c02778