The result is that you can use Pig as a component to build larger and more complex applications that tackle real business problems. Pig works with data from many sources, including structured and unstructured data, and store the results into the Hadoop Data File System. Pig scripts are translated into a series of MapReduce jobs that are run on the Apache Hadoop cluster.
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Download the driver data file from here. Once you have the file you will need to unzip the file into a directory. That is the views menu. The HDP file system is separate from the local file system. When finished, notice that both files are now in HDFS.
Note: In this tutorial Vi is used; however, any text editor will work as long as the files we create are stored on the Sandbox. This action creates one or more MapReduce jobs. After a moment, the script starts and the page changes. When the job completes, result output.
Modify line 1 of your script and add the following AS clause to define a schema for the truck events data. Open Vi and enter the following script:. Note: Recall that we used :x to save the script and pig -f Truck-Events to run the job. You can define a new relation based on an existing one. Pig Latin is procedural and fits very naturally in the pipeline paradigm while SQL is instead declarative. Pig Latin allows users to specify an implementation or aspects of an implementation to be used in executing a script in several ways. SQL is oriented around queries that produce a single result.
SQL handles trees naturally, but has no built in mechanism for splitting a data processing stream and applying different operators to each sub-stream. Pig Latin script describes a directed acyclic graph DAG rather than a pipeline. Pig Latin's ability to include user code at any point in the pipeline is useful for pipeline development. If SQL is used, data must first be imported into the database, and then the cleansing and transformation process can begin. From Wikipedia, the free encyclopedia.
Old version. Older version, still supported. Latest version. Latest preview version. Future release. Collecting huge amounts of unstructured data does not help unless there is an effective way to draw meaningful insights from it. Hadoop Developers have to filter and aggregate the data to leverage it for business analytics. Any big data problem requires hadoop developers to use the right tool for the job to get it done faster and better.
To do this, there are various coding approaches like using the Hadoop MapReduce or alternate components like Apache Pig and Hive.
Each of these coding approaches has some pros and cons. It is up to the hadoop developers to evaluate which coding approach will work best for their business requirements and skills. For programmers who are not well-versed with what Hadoop MapReduce is, here is an explanation.
Pig and Hive are components that sit on top of Hadoop framework for processing large data sets without the users having to write Java based MapReduce code. Pig and Hive open source alternatives to Hadoop MapReduce were built so that hadoop developers could do the same thing in Java in a less verbose way by writing only fewer lines of code that is easy to understand. Pig, Hive and MapReduce coding approaches are complementary components on the Hadoop stack. MapReduce is a powerful programming model for parallelism based on rigid procedural structure.
By using Hadoop MapReduce as the coding approach - it is hard to achieve join functionality making it difficult and time consuming to implement complex business logic. There is lot of development effort required to decide on how different Map and Reduce joins will take place and there could be chances that hadoop developers might not be able to map the data into the particular schema format. However, the advantage is that MapReduce provides more control for writing complex business logic when compared to Pig and Hive.
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At times, the job might require several hive queries for instance 12 levels of nested FROM clauses then it becomes difficult for Hadoop developers to write using MapReduce coding approach. Most of the jobs can be run using Pig and Hive but to make use of the advanced application programming interfaces, hadoop developers must make use of MapReduce coding approach.
If there are any large data sets that Pig and Hive cannot handle for instance key distribution then Hadoop MapReduce comes to the rescue. There are certain circumstances when hadoop developers can choose to use Hadoop MapReduce over Pig and Hive-. However, the above choices depend on various non-technical limitations like design, money, coupling decisions, time and expertise. It is an undeniable fact that Hadoop MapReduce is characteristically the best with performance. Pig and Hive are slowly and openly entering into the above list by intensifying their feature sets.
Pig has tools for data storage, data execution and data manipulation. Pig Latin is highly promoted by Yahoo as all the data engineers at Yahoo use Pig for processing data on the biggest hadoop clusters in the world.
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