I try running a map reduce on some data on a cluster and get the following output. This is my reducer From what I understand the problem is that hadoop treats lastCK and key as the same object and this condition will always be true This is my CompositeKey class I tried changing setters to something along this lines where
Tag: hadoop
/bin/bash: /bin/java: No such file or directory error in Yarn apps in MacOS
I was trying to run a simple wordcount MapReduce Program using Java 1.7 SDK and Hadoop2.7.1 on Mac OS X EL Captain 10.11 and I am getting the following error message in my container log “stderr” /bin/bash: /bin/java: No such file or directory Application Log- Command I am Running My ENV variable are- The problem seems to be because YARN
Hive NVL does not work with Date type of the column – NullpointerException
I am using MapR Hive distribution over HDFS and facing below issue. If for a table the column type is ‘Date’ type, then the NVL function does not work. The same is working for other datatype. It simply throws Even explain function is throwing same exception. Kindly help here. Is it a bug in Hive distribution? Answer I solved the
Hadoop 2.6.0 Browsing filesystem Java
I have installed a basic hadoop cluster on CentOS 6.6 and want to write a few basic programs (browse the filesystem, delete/add files, etc) but I’m struggling to get even the most basic app working. When running some basic code to list the contents of a directory to the console I get the following error: My pom.xml dependencies The code:
Increase the java heap space of a certain app
I have an application that I want to run it and gives it more heap memory. I run my application using this command in terminal: home/bin/hadoop jar $pathofjarfile parameter1 parameter2 but I don’t know how to allocate more heap memory when running this application? if anyone could please advise. Answer The easiest method to increase the heap space is using
Map Reduce flow in Hadoop
I’m learning Hadoop using the book Hadoop in Practice, and while reading chapter 1 i came across this diagram: From the Hadoop docs:(http://hadoop.apache.org/docs/current2/api/org/apache/hadoop/mapred/Reducer.html) 1.Shuffle Reducer is input the grouped output of a Mapper. In the phase the framework, for each Reducer, fetches the relevant partition of the output of all the Mappers, via HTTP. 2.Sort The framework groups Reducer inputs
Hadoop “Unable to load native-hadoop library for your platform” warning
I’m currently configuring hadoop on a server running CentOs. When I run start-dfs.sh or stop-dfs.sh, I get the following error: WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform… using builtin-java classes where applicable I’m running Hadoop 2.2.0. Doing a search online brought up this link: http://balanceandbreath.blogspot.ca/2013/01/utilnativecodeloader-unable-to-load.html However, the contents of /native/ directory on hadoop 2.x appear to be