Tag Archives: sql

10 MapReduce Tips

Categories: General Hadoop MapReduce

This piece is based on the talk “Practical MapReduce” that I gave at Hadoop User Group UK on April 14.

1. Use an appropriate MapReduce language

There are many languages and frameworks that sit on top of MapReduce, so it’s worth thinking up-front which one to use for a particular problem. There is no one-size-fits-all language; each has different strengths and weaknesses.

  • Java: Good for: speed;

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5 Common Questions About Apache Hadoop

Categories: General Hadoop

There’s been a lot of buzz about Apache Hadoop lately. Just the other day, some of our friends at Yahoo! reclaimed the terasort record from Google using Hadoop, and the folks at Facebook let on that they ingest 15 terabytes a day into their 2.5 petabyte Hadoop-powered data warehouse.

But many people still find themselves wondering just how all this works, and what it means to them. We get a lot of common questions while working with customers,

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Database Access with Apache Hadoop

Categories: General Hadoop MapReduce

Editor’s note (added Nov. 9. 2013): Valuable data in an organization is often stored in relational database systems. To access that data, you could use external APIs as detailed in this blog post below, or you could use Apache Sqoop, an open source tool (packaged inside CDH) that allows users to import data from a relational database into Apache Hadoop for further processing. Sqoop can also export those results back to the database for consumption by other clients.

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Job Scheduling in Apache Hadoop

Categories: Hadoop MapReduce

(guest blog post by Matei Zaharia)

When Apache Hadoop started out, it was designed mainly for running large batch jobs such as web indexing and log mining. Users submitted jobs to a queue, and the cluster ran them in order. However, as organizations placed more data in their Hadoop clusters and developed more computations they wanted to run, another use case became attractive: sharing a MapReduce cluster between multiple users.

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