MapReduce

Spark give Null pointer exception during InputSplit for Hbase

由 痴心易碎 提交于 2020-01-14 08:51:06
问题 I am using Spark 1.2.1,Hbase 0.98.10 and Hadoop 2.6.0. I got a null point exception while retrieve data form hbase. Find stack trace below. [sparkDriver-akka.actor.default-dispatcher-2] DEBUG NewHadoopRDD - Failed to use InputSplit#getLocationInfo. java.lang.NullPointerException: null at scala.collection.mutable.ArrayOps$ofRef$.length$extension(ArrayOps.scala:114) ~[scala-library-2.10.4.jar:na] at scala.collection.mutable.ArrayOps$ofRef.length(ArrayOps.scala:114) ~[scala-library-2.10.4.jar:na

MapReduce关系代数运算——投影

由 核能气质少年 提交于 2020-01-14 07:02:22
MapReduce关系代数运算——投影 关系沿用上一个选择运算的关系R，StudentR类也是一致的，本博文中就不赘述了。 MapReduce程序设计 Projection import org . apache . hadoop . conf . Configuration ; import org . apache . hadoop . fs . Path ; import org . apache . hadoop . io . LongWritable ; import org . apache . hadoop . io . NullWritable ; import org . apache . hadoop . io . Text ; import org . apache . hadoop . mapreduce . Job ; import org . apache . hadoop . mapreduce . Mapper ; import org . apache . hadoop . mapreduce . lib . input . FileInputFormat ; import org . apache . hadoop . mapreduce . lib . input . TextInputFormat ; import org . apache

How to pass system property to map function in hadoop

由 泄露秘密 提交于 2020-01-14 02:21:07
问题 is there a way how to pass system parameter (something like -Dmy_param=XXX) to map function in hadoop map reduce framework. Submission of job to hadoop cluster is done via .setJarByClass(). In mapper I have to create configuration so I would like to make it configerable so I thought that standard way via property file would be ok. Just struggling with passing parameter where the property is set. Another way would be to add property file to submitted jar. Does someone have an experience how

java.io.IOException: Cannot obtain block length for LocatedBlock

由 本小妞迷上赌 提交于 2020-01-13 19:46:32
问题 I am using HDP 2.1. for the cluster. I've encountered below exception and the MapReduce jobs have been failed because of that. Actually, we regularly create tables using the data from Flume which is ver. 1.4. and I checked the data files which mapper tried to read but I couldn't find anything on that. 2014-11-28 00:08:28,696 WARN [main] org.apache.hadoop.metrics2.impl.MetricsConfig: Cannot locate configuration: tried hadoop-metrics2-maptask.properties,hadoop-metrics2.properties 2014-11-28 00

Read values wrapped in Hadoop ArrayWritable

由 时光毁灭记忆、已成空白 提交于 2020-01-13 18:14:08
问题 I am new to Hadoop and Java. My mapper outputs text and Arraywritable. I having trouble to read ArrayWritable values. Unbale to cast .get() values to integer. Mapper and reducer code are attached. Can someone please help me to correct my reducer code in order to read ArrayWritable values? public static class Temp2Mapper extends Mapper<LongWritable, Text, Text, ArrayWritable>{ private static final int MISSING=9999; @Override public void map(LongWritable key, Text value, Context context) throws

CouchDB - filter latest log per logged instance from a list

由 有些话、适合烂在心里 提交于 2020-01-13 17:06:15
问题 I could use some help filtering distinct values from a couchdb view. I have a database that stores logs with information about computers. Periodically new logs for a computer are written to the db. A bit simplified i store entries like these: { "name": "NAS", "os": "Linux", "timestamp": "2011-03-03T16:26:39Z", } { "name": "Server1", "os": "Windows", "timestamp": "2011-02-03T19:31:31Z", } { "name": "NAS", "os": "Linux", "timestamp": "2011-02-03T18:21:29Z", } So far i am struggling to filter

CouchDB - filter latest log per logged instance from a list

由 自古美人都是妖i 提交于 2020-01-13 17:05:05
问题 I could use some help filtering distinct values from a couchdb view. I have a database that stores logs with information about computers. Periodically new logs for a computer are written to the db. A bit simplified i store entries like these: { "name": "NAS", "os": "Linux", "timestamp": "2011-03-03T16:26:39Z", } { "name": "Server1", "os": "Windows", "timestamp": "2011-02-03T19:31:31Z", } { "name": "NAS", "os": "Linux", "timestamp": "2011-02-03T18:21:29Z", } So far i am struggling to filter

wrong value class: class org.apache.hadoop.io.Text is not class org.apache.hadoop.io.IntWritable

由 混江龙づ霸主 提交于 2020-01-13 10:11:11
问题 I have used one mapper,one reducer and one combiner class but I am getting the error as below: java.io.IOException: wrong value class: class org.apache.hadoop.io.Text is not class org.apache.hadoop.io.IntWritable at org.apache.hadoop.mapred.IFile$Writer.append(IFile.java:199) at org.apache.hadoop.mapred.Task$CombineOutputCollector.collect(Task.java:1307) at org.apache.hadoop.mapred.Task$NewCombinerRunner$OutputConverter.write(Task.java:1623) at org.apache.hadoop.mapreduce.task

When using HBase as a source for MapReduce, can I extend TableInputFormatBase to create multiple splits and multiple mappers for each region?

由 淺唱寂寞╮ 提交于 2020-01-13 08:25:12
问题 I'm thinking about using HBase as a source for one of my MapReduce jobs. I know that TableInputFormat specifies one input split (and thus one mapper) per Region. However, this seems inefficient. I'd really like to have multiple mappers working on a given Region at once. Can I achieve this by extending TableInputFormatBase? Can you please point me to an example? Furthermore, is this even a good idea? Thanks for the help. 回答1: You need a custom input format that extends InputFormat. you can get

CDH5.2: MR, Unable to initialize any output collector

由 守給你的承諾、 提交于 2020-01-13 04:42:07
问题 Cloudera CDH5.2 Quickstart VM Cloudera Manager showing all nodes state = GREEN I've jared on Eclipse a MR job including all relevant cloudera jars in the Build Path: avro-1.7.6-cdh5.2.0.jar, avro-mapred-1.7.6-cdh5.2.0-hadoop2.jar, hadoop-common-2.5.0-cdh5.2.0.jar, hadoop-mapreduce-client-core-2.5.0-cdh5.2.0.jar I've run the following job hadoop jar jproject1.jar avro00.AvroUserPrefCount -libjars ${LIBJARS} avro/00/in avro/00/out I get the following error, is it a Java heap problem, any
订阅 MapReduce