MapReduce

MapReduce java program to calaculate max temperature not starting to run,it is run on local desktop importing external jar files

由 北战南征 提交于 2019-12-07 08:35:29
1>THIS IS MY MAIN METHOD package dataAnalysis; import java.io.IOException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapred.FileOutputFormat; import org.apache.hadoop.mapred.JobConf; import org.apache.hadoop.mapred.TextOutputFormat; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; public class Weather { public static void main(String[] args) { JobConf conf=new JobConf(); Job job; try { job = new Job(conf,

Writing reduce function in couchbase

由 ℡╲_俬逩灬. 提交于 2019-12-07 08:28:47
问题 This is my first attempt at couchbase. My json doc looks like this: { "member_id": "12345", "devices": [ { "device_id": "1", "hashes": [ "h1", "h2", "h3", "h4" ] }, { "device_id": "2", "hashes": [ "h1", "h2", "h3", "h4", "h5", "h6", "h7" ] } ] } I want to create a view which tells me all member_ids for a given hash. Something like this: h1["12345","233","2323"] //233,2323 are other member id h2["12345"] The member_id should appear once in the set. I wrote a map function function (doc, meta) {

Hadoop gzip input file using only one mapper [duplicate]

由 心不动则不痛 提交于 2019-12-07 08:13:45
问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: Why can't hadoop split up a large text file and then compress the splits using gzip? I found that when using input file that is gzipped the Hadoop chooses to allocate only one map task to handle my map/reduce job. The gzipped file is more than 1.4 GB, so I would expect many mappers to run in parallel (exacly like when using un-zipped file) Is there any configuration I can do to improve it? 回答1: Gzip files can't

HBase Map-only Row Delete

由 吃可爱长大的小学妹 提交于 2019-12-07 08:07:35
问题 First time writing a HBase mapreduce and I'm having trouble deleting rows in HBase (trying to run it as a map-only job). The job succeeds and is able to scan the HBase table and I'm able to get the correct rowkeys in the mapper read from HBase (verified through sysout). However, it seems like the call to Delete del = new Delete(row.get()) isn't actually doing anything. Below is the code I'm trying to run: HBaseDelete.java public class HBaseDelete { public static void main(String[] args)

why map task always running on a single node

由 本秂侑毒 提交于 2019-12-07 08:02:33
问题 I have a Fully-Distributed Hadoop cluster with 4 nodes.When I submit my job to Jobtracker which decide 12 map tasks will be cool for my job,something strange happens.The 12 map tasks always running on a single node instead of running on the entire cluster.Before I ask the question ,I have already done the things below: Try different Job Run start-balance.sh to rebalance the cluster But it does not work,so I hope someone can tell me why and how to fix it. 回答1: If all the blocks of input data

Apache Spark mapPartitionsWithIndex

由 你离开我真会死。 提交于 2019-12-07 07:58:43
问题 Can someone give example of correct usage of mapPartitionsWithIndex in Java? I've found a lot of Scala examples, but there is lack of Java ones. Is my understanding correct that separate partitions will be handled by separate nodes when using this function. I am getting the following error method mapPartitionsWithIndex in class JavaRDD<T> cannot be applied to given types; JavaRDD<String> rdd = sc.textFile(filename).mapPartitionsWithIndex required: Function2<Integer,Iterator<String>,Iterator<R

mapreduce distance calculation in hadoop

由 瘦欲@ 提交于 2019-12-07 07:37:29
问题 Is there a distance calculation implementation using hadoop map/reduce. I am trying to calculate a distance between a given set of points. Looking for any resources. Edit This is a very intelligent solution. I have tried some how like the first algorithm, and I get almost what I was looking for. I am not concerned about optimizing the program at the moment, but my problem was the dist(X,Y) function was not working. When I got all the points on the reducer, I was unable to go through all the

Passing parameters from one action to another in Oozie

由 假如想象 提交于 2019-12-07 07:29:22
I have a following shell script: DATE= date +"%d%b%y" -d "-1 days" How can I pass DATE to a Java action? You can capture output from shell script and pass it to java action.In the shell script , echo the property like 'dateVariable=${DATE}' and add the capture-output element int the shell action. This will let you capture dateVariable from shell script.In the java action, You can pass the captured variable as parameter as ${wf:actionData('shellAction')['dateVariable']} where shellAction is the shell action name. Sample workflow :- <?xml version="1.0" encoding="UTF-8"?> <workflow-app xmlns="uri

Why cannot more than 32 cores be requested from YARN to run a job?

由 落爺英雄遲暮 提交于 2019-12-07 07:07:13
问题 Setup: No. of nodes: 3 No. of cores: 32 Cores per machine RAM: 410GB per machine Spark Version: 1.2.0 Hadoop Version: 2.4.0 (Hortonworks) Objective: I want to run a Spark job with more than 32 executor cores. Problem: When I request more than 32 executor cores for Spark job, I get the following error: Uncaught exception: Invalid resource request, requested virtual cores < 0, or requested virtual cores > max configured, requestedVirtualCores=150, maxVirtualCores=32 at org.apache.hadoop.yarn

Hadoop mapreduce has “Cannot resolve the host name” error

由 我怕爱的太早我们不能终老 提交于 2019-12-07 06:27:01
问题 Now I run Hadoop mapreduce job, the input data comes from HBase table, recently there is an error, the error is below: ERROR mapreduce.TableInputFormatBase: Cannot resolve the host name for /172.16.4.195 because of javax.naming.NameNotFoundException: DNS name not found [response code 3]; remaining name '195.4.16.172.in-addr.arpa' * 172.16.4.195 *is cluster node(slave)ip adress, I do not know what is "195.4.16.172". There was no such error when I firstly run this job,I do not know why there is
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