September 2012
Intermediate to advanced
350 pages
9h 46m
English
Content preview from Programming HiveBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Chapter 12. Developing
Hive won’t provide everything you could possibly need. Sometimes a third-party library will fill a gap. At other times, you or someone else who is a Java developer will need to write user-defined functions (UDFs; see Chapter 13), SerDes (see Record Formats: SerDes), input and/or output formats (see Chapter 15), or other enhancements.
This chapter explores working with the Hive source code itself, including the new Plugin Developer Kit introduced in Hive v0.8.0.
Changing Log4J Properties
Hive can be configured with two separate Log4J configuration files found in $HIVE_HOME/conf. The hive-log4j.properties file controls the logging of the CLI or other locally launched components. The hive-exec-log4j.properties file controls the logging inside the MapReduce tasks. These files do not need to be present inside the Hive installation because the default properties come built inside the Hive JARs. In fact, the actual files in the conf directory have the .template extension, so they are ignored by default. To use either of them, copy it with a name that removes the .template extension and edit it to taste:
$cp conf/hive-log4j.properties.template conf/hive-log4j.properties$... edit file ...
It is also possible to change the logging configuration of Hive
temporarily without copying and editing the Log4J files. The hiveconf switch can be specified on start-up
with definitions of any properties in the
log4.properties file. For example, here we set the default logger to the ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.