Apache Hadoop Word Count error
Question
I have many records store in my mongodb. Just looks like this:
{
"_id": xxxx,
"url":"www.myurl.com/xxxxx",
"summary":"THIS IS DOCUMENT IN THE $url"
}
What I want the result just looks like this:
{
"_id": word_in_summary,
"results":[
{
"url": "the corresponding url that word appears in summary",
"count": "the total count of the word in the summary"
},
{ .... }
]
}
for example:
{
"_id" : ObjectId("574ec02d8bee4f03d9174c11"),
"url" : "www.example_1.com/xxxx",
"summary" : "hello good, good"
}
{
"_id" : ObjectId("574ec02d8bee4f03d9174c12"),
"url" : "www.example_2.com/xxxx",
"summary" : "good"
}
So, the result is:
{
"_id": "hello",
"results":[
"url": "www.example_1.com/xxxx",
"count": 1
]
}
{
"_id": "good",
"results":[
{
"url": "www.example_1.com/xxxx",
"count": 2
},
{
"url": "www.example_2.com/xxxx",
"count": 1
}
]
}
I am a newbie in Java and Hadoop. My code to process the data is:
import java.util.*;
import java.io.*;
import org.bson.*;
import com.mongodb.hadoop.MongoInputFormat;
import com.mongodb.hadoop.MongoOutputFormat;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapreduce.*;
public class WordCount {
public static class TokenizerMapper extends Mapper<Object, BSONObject, Text, IntWritable> {
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, BSONObject value, Context context )
throws IOException, InterruptedException {
String url = value.get("url").toString();
StringTokenizer itr = new StringTokenizer(value.get("summary").toString().replaceAll(",", " "));
while (itr.hasMoreTokens()) {
word.set(itr.nextToken() + " " + url);
context.write(word, one);
}
}
}
public static class IntSumReducer extends Reducer<Text, IntWritable, Text, MapWritable> {
private MapWritable result = new MapWritable();
public void reduce(Text key, Iterable<IntWritable> values, Context context)
throws IOException, InterruptedException {
int sum = 0;
String str[] = key.toString().split(" ");
Text mykey= new Text(str[0]);
Text myurl = new Text(str[1]);
for (IntWritable val : values) {
sum += val.get();
}
System.out.println("sum : " + sum);
result.put(myurl, new IntWritable(sum));
context.write(mykey, result);
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
conf.set( "mongo.input.uri" , "mongodb://localhost/testmr.stackin" );
conf.set( "mongo.output.uri" , "mongodb://localhost/testmr.stackout" );
@SuppressWarnings("deprecation")
Job job = new Job(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
//job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(IntWritable.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(MapWritable.class);
job.setInputFormatClass( MongoInputFormat.class );
job.setOutputFormatClass( MongoOutputFormat.class );
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
The errors:
16/06/14 12:55:51 INFO Configuration.deprecation: session.id is deprecated. Instead, use dfs.metrics.session-id
16/06/14 12:55:51 INFO jvm.JvmMetrics: Initializing JVM Metrics with processName=JobTracker, sessionId=
16/06/14 12:55:52 WARN mapreduce.JobResourceUploader: Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.
16/06/14 12:55:53 INFO driver.cluster: Cluster created with settings {hosts=[localhost:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
16/06/14 12:55:53 INFO driver.cluster: No server chosen by ReadPreferenceServerSelector{readPreference=primary} from cluster description ClusterDescription{type=UNKNOWN, connectionMode=SINGLE, all=[ServerDescription{address=localhost:27017, type=UNKNOWN, state=CONNECTING}]}. Waiting for 30000 ms before timing out
16/06/14 12:55:53 INFO driver.connection: Opened connection [connectionId{localValue:1, serverValue:1}] to localhost:27017
16/06/14 12:55:53 INFO driver.cluster: Monitor thread successfully connected to server with description ServerDescription{address=localhost:27017, type=STANDALONE, state=CONNECTED, ok=true, version=ServerVersion{versionList=[2, 4, 9]}, minWireVersion=0, maxWireVersion=0, electionId=null, maxDocumentSize=16777216, roundTripTimeNanos=685985}
16/06/14 12:55:53 INFO driver.connection: Opened connection [connectionId{localValue:2, serverValue:2}] to localhost:27017
16/06/14 12:55:53 INFO driver.connection: Closed connection [connectionId{localValue:2, serverValue:2}] to localhost:27017 because the pool has been closed.
16/06/14 12:55:53 INFO driver.cluster: Cluster created with settings {hosts=[localhost:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
16/06/14 12:55:53 INFO driver.cluster: No server chosen by ReadPreferenceServerSelector{readPreference=primary} from cluster description ClusterDescription{type=UNKNOWN, connectionMode=SINGLE, all=[ServerDescription{address=localhost:27017, type=UNKNOWN, state=CONNECTING}]}. Waiting for 30000 ms before timing out
16/06/14 12:55:53 INFO driver.connection: Opened connection [connectionId{localValue:3, serverValue:3}] to localhost:27017
16/06/14 12:55:53 INFO driver.cluster: Monitor thread successfully connected to server with description ServerDescription{address=localhost:27017, type=STANDALONE, state=CONNECTED, ok=true, version=ServerVersion{versionList=[2, 4, 9]}, minWireVersion=0, maxWireVersion=0, electionId=null, maxDocumentSize=16777216, roundTripTimeNanos=599568}
16/06/14 12:55:53 INFO driver.connection: Opened connection [connectionId{localValue:4, serverValue:4}] to localhost:27017
16/06/14 12:55:53 WARN splitter.StandaloneMongoSplitter: WARNING: No Input Splits were calculated by the split code. Proceeding with a *single* split. Data may be too small, try lowering 'mongo.input.split_size' if this is undesirable.
16/06/14 12:55:53 INFO splitter.MongoCollectionSplitter: Created split: min=null, max= null
16/06/14 12:55:53 INFO driver.connection: Closed connection [connectionId{localValue:4, serverValue:4}] to localhost:27017 because the pool has been closed.
16/06/14 12:55:53 INFO mapreduce.JobSubmitter: number of splits:1
16/06/14 12:55:54 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_local35432891_0001
16/06/14 12:55:54 INFO mapreduce.Job: The url to track the job: http://localhost:8080/
16/06/14 12:55:54 INFO mapreduce.Job: Running job: job_local35432891_0001
16/06/14 12:55:54 INFO mapred.LocalJobRunner: OutputCommitter set in config null
16/06/14 12:55:54 INFO mapred.LocalJobRunner: OutputCommitter is com.mongodb.hadoop.output.MongoOutputCommitter
16/06/14 12:55:54 INFO output.MongoOutputCommitter: Setting up job.
16/06/14 12:55:54 INFO mapred.LocalJobRunner: Waiting for map tasks
16/06/14 12:55:54 INFO mapred.LocalJobRunner: Starting task: attempt_local35432891_0001_m_000000_0
16/06/14 12:55:54 INFO output.MongoOutputCommitter: Setting up task.
16/06/14 12:55:54 INFO mapred.Task: Using ResourceCalculatorProcessTree : [ ]
16/06/14 12:55:54 INFO mapred.MapTask: Processing split: MongoInputSplit{inputURI hosts=[localhost], inputURI namespace=testmr.stackin, min={ }, max={ }, query={ }, sort={ }, fields={ }, limit=0, notimeout=false}
16/06/14 12:55:55 INFO driver.cluster: Cluster created with settings {hosts=[localhost:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
16/06/14 12:55:55 INFO driver.connection: Opened connection [connectionId{localValue:5, serverValue:5}] to localhost:27017
16/06/14 12:55:55 INFO driver.cluster: Monitor thread successfully connected to server with description ServerDescription{address=localhost:27017, type=STANDALONE, state=CONNECTED, ok=true, version=ServerVersion{versionList=[2, 4, 9]}, minWireVersion=0, maxWireVersion=0, electionId=null, maxDocumentSize=16777216, roundTripTimeNanos=1312293}
16/06/14 12:55:55 INFO mapred.MapTask: (EQUATOR) 0 kvi 26214396(104857584)
16/06/14 12:55:55 INFO mapred.MapTask: mapreduce.task.io.sort.mb: 100
16/06/14 12:55:55 INFO mapred.MapTask: soft limit at 83886080
16/06/14 12:55:55 INFO mapred.MapTask: bufstart = 0; bufvoid = 104857600
16/06/14 12:55:55 INFO mapred.MapTask: kvstart = 26214396; length = 6553600
16/06/14 12:55:55 INFO mapred.MapTask: Map output collector class = org.apache.hadoop.mapred.MapTask$MapOutputBuffer
16/06/14 12:55:55 INFO driver.connection: Opened connection [connectionId{localValue:6, serverValue:6}] to localhost:27017
16/06/14 12:55:55 INFO input.MongoRecordReader: Read 4.0 documents from:
16/06/14 12:55:55 INFO input.MongoRecordReader: MongoInputSplit{inputURI hosts=[localhost], inputURI namespace=testmr.stackin, min={ }, max={ }, query={ }, sort={ }, fields={ }, limit=0, notimeout=false}
16/06/14 12:55:55 INFO mapred.LocalJobRunner:
16/06/14 12:55:55 INFO driver.connection: Closed connection [connectionId{localValue:6, serverValue:6}] to localhost:27017 because the pool has been closed.
16/06/14 12:55:55 INFO mapred.MapTask: Starting flush of map output
16/06/14 12:55:55 INFO mapred.MapTask: Spilling map output
16/06/14 12:55:55 INFO mapred.MapTask: bufstart = 0; bufend = 1252; bufvoid = 104857600
16/06/14 12:55:55 INFO mapred.MapTask: kvstart = 26214396(104857584); kvend = 26214340(104857360); length = 57/6553600
16/06/14 12:55:55 INFO mapred.MapTask: Finished spill 0
16/06/14 12:55:55 INFO mapred.Task: Task:attempt_local35432891_0001_m_000000_0 is done. And is in the process of committing
16/06/14 12:55:55 INFO Configuration.deprecation: mapred.child.tmp is deprecated. Instead, use mapreduce.task.tmp.dir
16/06/14 12:55:55 INFO mapred.LocalJobRunner: map
16/06/14 12:55:55 INFO mapred.Task: Task 'attempt_local35432891_0001_m_000000_0' done.
16/06/14 12:55:55 INFO mapred.LocalJobRunner: Finishing task: attempt_local35432891_0001_m_000000_0
16/06/14 12:55:55 INFO mapred.LocalJobRunner: map task executor complete.
16/06/14 12:55:55 INFO mapred.LocalJobRunner: Waiting for reduce tasks
16/06/14 12:55:55 INFO mapred.LocalJobRunner: Starting task: attempt_local35432891_0001_r_000000_0
16/06/14 12:55:55 INFO output.MongoOutputCommitter: Setting up task.
16/06/14 12:55:55 INFO mapred.Task: Using ResourceCalculatorProcessTree : [ ]
16/06/14 12:55:55 INFO mapred.ReduceTask: Using ShuffleConsumerPlugin: org.apache.hadoop.mapreduce.task.reduce.Shuffle@66d7bef1
16/06/14 12:55:55 INFO reduce.MergeManagerImpl: MergerManager: memoryLimit=334338464, maxSingleShuffleLimit=83584616, mergeThreshold=220663392, ioSortFactor=10, memToMemMergeOutputsThreshold=10
16/06/14 12:55:55 INFO reduce.EventFetcher: attempt_local35432891_0001_r_000000_0 Thread started: EventFetcher for fetching Map Completion Events
16/06/14 12:55:55 INFO reduce.LocalFetcher: localfetcher#1 about to shuffle output of map attempt_local35432891_0001_m_000000_0 decomp: 1284 len: 1288 to MEMORY
16/06/14 12:55:55 INFO reduce.InMemoryMapOutput: Read 1284 bytes from map-output for attempt_local35432891_0001_m_000000_0
16/06/14 12:55:55 INFO reduce.MergeManagerImpl: closeInMemoryFile -> map-output of size: 1284, inMemoryMapOutputs.size() -> 1, commitMemory -> 0, usedMemory ->1284
16/06/14 12:55:55 INFO reduce.EventFetcher: EventFetcher is interrupted.. Returning
16/06/14 12:55:55 INFO mapred.LocalJobRunner: 1 / 1 copied.
16/06/14 12:55:55 INFO reduce.MergeManagerImpl: finalMerge called with 1 in-memory map-outputs and 0 on-disk map-outputs
16/06/14 12:55:55 INFO mapred.Merger: Merging 1 sorted segments
16/06/14 12:55:55 INFO mapred.Merger: Down to the last merge-pass, with 1 segments left of total size: 1197 bytes
16/06/14 12:55:55 INFO reduce.MergeManagerImpl: Merged 1 segments, 1284 bytes to disk to satisfy reduce memory limit
16/06/14 12:55:55 INFO reduce.MergeManagerImpl: Merging 1 files, 1288 bytes from disk
16/06/14 12:55:55 INFO reduce.MergeManagerImpl: Merging 0 segments, 0 bytes from memory into reduce
16/06/14 12:55:55 INFO mapred.Merger: Merging 1 sorted segments
16/06/14 12:55:55 INFO mapred.Merger: Down to the last merge-pass, with 1 segments left of total size: 1197 bytes
16/06/14 12:55:55 INFO mapred.LocalJobRunner: 1 / 1 copied.
16/06/14 12:55:55 INFO driver.cluster: Cluster created with settings {hosts=[localhost:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
16/06/14 12:55:55 INFO driver.connection: Opened connection [connectionId{localValue:7, serverValue:7}] to localhost:27017
16/06/14 12:55:55 INFO driver.cluster: Monitor thread successfully connected to server with description ServerDescription{address=localhost:27017, type=STANDALONE, state=CONNECTED, ok=true, version=ServerVersion{versionList=[2, 4, 9]}, minWireVersion=0, maxWireVersion=0, electionId=null, maxDocumentSize=16777216, roundTripTimeNanos=414057}
16/06/14 12:55:55 INFO output.MongoRecordWriter: Writing to temporary file: tmp/attempt_local35432891_0001_r_000000_0/_MONGO_OUT_TEMP/_out
16/06/14 12:55:55 INFO Configuration.deprecation: mapred.skip.on is deprecated. Instead, use mapreduce.job.skiprecords
sum : 1
16/06/14 12:55:55 INFO mapreduce.Job: Job job_local35432891_0001 running in uber mode : false
16/06/14 12:55:55 INFO mapreduce.Job: map 100% reduce 0%
16/06/14 12:55:56 INFO mapred.LocalJobRunner: reduce task executor complete.
16/06/14 12:55:56 WARN mapred.LocalJobRunner: job_local35432891_0001
java.lang.Exception: java.lang.IllegalArgumentException: Can't serialize class org.apache.hadoop.io.IntWritable
at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:462)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:529)
Caused by: java.lang.IllegalArgumentException: Can't serialize class org.apache.hadoop.io.IntWritable
at org.bson.BasicBSONEncoder._putObjectField(BasicBSONEncoder.java:202)
at org.bson.BasicBSONEncoder.putObject(BasicBSONEncoder.java:111)
at com.mongodb.hadoop.io.BSONWritable.write(BSONWritable.java:93)
at com.mongodb.hadoop.output.MongoRecordWriter.write(MongoRecordWriter.java:125)
at org.apache.hadoop.mapred.ReduceTask$NewTrackingRecordWriter.write(ReduceTask.java:558)
at org.apache.hadoop.mapreduce.task.TaskInputOutputContextImpl.write(TaskInputOutputContextImpl.java:89)
at org.apache.hadoop.mapreduce.lib.reduce.WrappedReducer$Context.write(WrappedReducer.java:105)
at WordCount$IntSumReducer.reduce(WordCount.java:46)
at WordCount$IntSumReducer.reduce(WordCount.java:33)
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:171)
at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:627)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:389)
at org.apache.hadoop.mapred.LocalJobRunner$Job$ReduceTaskRunnable.run(LocalJobRunner.java:319)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
16/06/14 12:55:56 INFO mapreduce.Job: Job job_local35432891_0001 failed with state FAILED due to: NA
16/06/14 12:55:56 INFO mapreduce.Job: Counters: 38
File System Counters
FILE: Number of bytes read=3893
FILE: Number of bytes written=260587
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=0
HDFS: Number of bytes written=0
HDFS: Number of read operations=1
HDFS: Number of large read operations=0
HDFS: Number of write operations=0
Map-Reduce Framework
Map input records=4
Map output records=15
Map output bytes=1252
Map output materialized bytes=1288
Input split bytes=201
Combine input records=0
Combine output records=0
Reduce input groups=0
Reduce shuffle bytes=1288
Reduce input records=0
Reduce output records=0
Spilled Records=15
Shuffled Maps =1
Failed Shuffles=0
Merged Map outputs=1
GC time elapsed (ms)=4
CPU time spent (ms)=0
Physical memory (bytes) snapshot=0
Virtual memory (bytes) snapshot=0
Total committed heap usage (bytes)=240648192
Shuffle Errors
BAD_ID=0
CONNECTION=0
IO_ERROR=0
WRONG_LENGTH=0
WRONG_MAP=0
WRONG_REDUCE=0
File Input Format Counters
Bytes Read=0
File Output Format Counters
Bytes Written=0
After
How should I fix it? Thank you!
1 answers
solution1
1 ACCPTED 2016-06-14 02:15:53
In your reducer, your output value is result which is type MapWritable . If that's your intention, you need to replace this line
job.setOutputValueClass(IntWritable.class);
with
job.setOutputValueClass(MapWritable.class);
Since the mapper output is different from reducer(final) output, you should also set
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(IntWritable.class);
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.
Related Question
Error - Hadoop Word Count Program in MapReduce
Hadoop word count
Running word count on hadoop
Cannot run word count on hadoop
Hadoop Mapreduce word count Program
Hadoop - word count per node
Error while submitting word count topology in Apache storm
Hadoop word count example without root permissions
Hadoop word count example - null pointer exception
map 100% reduce 0% in running hadoop word count
Related Tags