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22 discussions - 62 posts

  • Hi, all I saw that in *-site.xml, we can use ${user.name} to get the username of present user. If I want to get the environment $HOSTNAME, what should I do? I tried ${HOSTNAME}, ${env.hostname}, both ...
    Lu welmanLu welman
    Mar 11, 2010 at 2:51 pm
    Mar 25, 2010 at 6:21 pm
  • Hi, I am new to Hadoop and need some help on writing bytes from map and reduce functions. I take K1, V1 as Text, Text for Map as input. I want to output K2, V2 from Map where K2 is Text and V2 is ...
    Saliya EkanayakeSaliya Ekanayake
    Mar 31, 2010 at 4:24 am
    Apr 1, 2010 at 8:04 pm
  • Hi, I'm new to Hadoop, and I'm trying to figure out the best way to use it with EC2 to make large number of calls to a web API, and then process and store the results. I'm completely new to Hadoop, ...
    Phil McCarthyPhil McCarthy
    Mar 6, 2010 at 5:30 pm
    Mar 9, 2010 at 10:45 pm
  • Hi, I am running hadoop over a collection of several millions of small files using the CombineFileInputFormat. However, when generating splits, the job fails because of a Garbage Collector Overhead ...
    Mohamed Riadh TradMohamed Riadh Trad
    Mar 23, 2010 at 4:00 pm
    Mar 24, 2010 at 2:51 pm
  • Hi, all transform is that: map: (k1, v1) - list(k2, v2) reduce: (k2, list(v2)) - list(v2) Here, the output value type is v2, and the final type is also v2. But, what I want to achieve is that, the ...
    welman Luwelman Lu
    Mar 21, 2010 at 4:13 pm
    Mar 22, 2010 at 7:27 am
  • Hi All, I am new to hadoop and is using Python to write MapReduce tasks. In order to execute the streaming command I am using the following command. bin/hadoop jar hadoop-0.20.0-streaming.jar -mapper ...
    Venkata subbarayuduVenkata subbarayudu
    Mar 18, 2010 at 5:54 am
    Mar 18, 2010 at 6:28 pm
  • Hi, I am trying to upgrade my scripts to the new MapReduce API in org.apache.hadoop.mapreduce. I had a join operation that relied on the MultipleInputs.class in the mapred folder, but I see it is not ...
    Chris BatesChris Bates
    Mar 12, 2010 at 2:12 am
    Mar 13, 2010 at 1:52 am
  • Hi all, I want to implement a CompositeMapper which delegates its map() calls to a collection of registered mappers (similar to the DelegatingMapper, but with more than one registered Mapper). ...
    Thomas ThevisThomas Thevis
    Mar 23, 2010 at 12:56 pm
    Mar 24, 2010 at 8:20 am
  • Hi I am writing map-reduce program with hadoop-0.20.1, new mapreduce api. I applied GroupComparator with job.setGroupingComparatorClass(GroupComparator.class);, but it does not seem to work in ...
    Bae, Jae HyeonBae, Jae Hyeon
    Mar 8, 2010 at 6:42 am
    Mar 9, 2010 at 2:38 pm
  • Hi, everyone! The problem what I met is that, I want to transform a local disk file into bytesWritable to output. Now, all I found is only can use FileSystem.copyFromLocalFile to copy a file from ...
    welman Luwelman Lu
    Mar 16, 2010 at 6:53 pm
    Mar 16, 2010 at 7:35 pm
  • Hi, When I'm running an hadoop example: $ bin/hadoop jar build/hadoop-0.20.2-dev-examples.jar wordcount gutenberg gutenberg-output I've noticed that it's created a job.jar file with classes of the ...
    Psdc1978Psdc1978
    Mar 15, 2010 at 3:48 pm
    Mar 15, 2010 at 4:01 pm
  • Hi, Is there a way to set the output group for a mapreduce (or hdfs fs operation) job? For example -Ddfs.umaskmode=027 successfully sets the permissions. I would think the -Dgroup.name=GROUP would do ...
    Gregory LawrenceGregory Lawrence
    Mar 11, 2010 at 7:07 pm
    Mar 11, 2010 at 7:10 pm
  • Hi Hadoop, Hive, and Sqoop users, For the past year, the Apache Hadoop MapReduce project has played host to Sqoop, a command-line tool that performs parallel imports and exports between relational ...
    Aaron KimballAaron Kimball
    Mar 29, 2010 at 7:03 pm
    Mar 29, 2010 at 7:03 pm
  • Hi all, I'm finding that the mechanism I'm relying on to make my dependencies available doesn't work when the job jar is in my classpath. Example: MyJob.jar contains these files: ...
    Matt SteeleMatt Steele
    Mar 24, 2010 at 1:39 am
    Mar 24, 2010 at 1:39 am
  • Hi everyone. I tried to MapFile.fix with block compressed SequenceFile, but I found that fixed MapFile could not find several keys. I investigated the cause, it was on SequenceFile.Reader.readBlock. ...
    Bae, Jae HyeonBae, Jae Hyeon
    Mar 22, 2010 at 7:24 am
    Mar 22, 2010 at 7:24 am
  • Moving to mapreduce-user@ Not really, what is the use case?
    Arun C MurthyArun C Murthy
    Mar 17, 2010 at 11:19 pm
    Mar 17, 2010 at 11:19 pm
  • Hi, I would like to understand what's the purpose of a setup and cleanup task. During the start-up of the job tracker, it will be assigned 2 setup tasks and 2 cleanup tasks for map and for the ...
    Psdc1978Psdc1978
    Mar 14, 2010 at 11:34 am
    Mar 14, 2010 at 11:34 am
  • Moving to mapreduce-user@, bcc: common-user Have you tried bumping up the heap for the map task? Since you are setting io.sort.mb to 256M, pls set heap-size to 512M at least, if not more. ...
    Arun C MurthyArun C Murthy
    Mar 11, 2010 at 5:28 pm
    Mar 11, 2010 at 5:28 pm
  • Hi all, Why hadoop jobs need setup and cleanup phases which would consume a lot of time ? Why could not we archieve it like distributed RDBMS does, a master process coordinates all salve nodes ...
    Min ZhouMin Zhou
    Mar 10, 2010 at 3:48 am
    Mar 10, 2010 at 3:48 am
  • Hi, I have a python based map reduce application. I would like to define my own paritioner, (just like I would have done with pipes/java). How do I specify the jar file that contains my custom ...
    Erez KatzErez Katz
    Mar 5, 2010 at 2:28 am
    Mar 5, 2010 at 2:28 am
  • (We apologize if you have received multiple copies of this CFP) ------------------------------------------------------------------- CALL FOR PAPERS The First International Workshop on MapReduce and ...
    Gilles FedakGilles Fedak
    Mar 3, 2010 at 9:22 am
    Mar 3, 2010 at 9:22 am
  • Hi, I've look to the hadoop-0.20.1 source and I've the following questions: 1 - As I understand from the source code, LocalJobRunner is a class used to run a map or reduce task. But a MR task is ...
    Psdc1978Psdc1978
    Mar 2, 2010 at 8:51 pm
    Mar 2, 2010 at 8:51 pm
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23 users for March 2010

welman Lu: 15 posts Bae, Jae Hyeon: 6 posts Jeff Zhang: 6 posts Aaron Kimball: 3 posts Erez Katz: 3 posts Phil McCarthy: 3 posts Psdc1978: 3 posts Saliya Ekanayake: 3 posts Arun C Murthy: 2 posts Chris Bates: 2 posts Mohamed Riadh Trad: 2 posts Thomas Thevis: 2 posts Venkata subbarayudu: 2 posts Alex Kozlov: 1 post Allen Wittenauer: 1 post Amareshwari Sri Ramadasu: 1 post Amogh Vasekar: 1 post Gilles Fedak: 1 post Gregory Lawrence: 1 post Karthik K: 1 post
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