Re: nutch crawldb failed for java heap space

>
> Thanks, i think you are not read my issue carefully.
> your suggestion in the reply I have tested for long time.
>
>
> On Sun, Jul 5, 2009 at 9:46 PM, Julien Nioche <
> lists.digitalpebble@...> wrote:
>
>> See https://issues.apache.org/jira/browse/NUTCH-702 for a patch to reduce
>> the memory consumption.
>> You are not setting the heapsize in the right way. This should be done in
>> the hadoop-site.xml using the parameter mapred.child.java.opts. Changing
>> hadoop-env modifies the amount of memory to be used for the services
>> (JobTracker, DataNodes, etc...) but not for the hadoop tasks
>>
>> HTH
>>
>> Julien
>>
>>
>>
>> 2009/7/2 lei wang <nutchmaillist@...>
>>
>> >  Hi,everyone, these days a  nutch problem occur to me when I test nutch
>> to
>> > index 2 millions pages.
>> >
>> > When then program steps into the reduce stage of crawldb update, the
>> error
>> > messeges gives as below:
>> > Before this test, I try to crawl and index 1 millions pages, nutch goes
>> > well.
>> > I alter  the HADOOP_HEAPSIZE  in the hadoop-env.sh,  1000m,2000m, even
>>  to
>> > my memory size 6GB, but make no different. And change the value of
>> >  properties "mapred.child.java.opts" by 200m, 1000m, 2000m,4000m,~ 6GB
>> time
>> > and again , but it seems no difference.
>> >
>> > I have 9 machines(CPU core 2 2.8GHZ, 6GB RAM,) , 1 master ,and 8
>> > slaves(tasktrack).
>> > I attach the hadoop-env.sh and hadoop-site.xml files after this
>> > messege, appreciate your help very much.
>> > ============================================================
>> >
>> > java.lang.OutOfMemoryError: GC overhead limit exceeded
>> >        at java.util.HashMap.<init>(HashMap.java:209)
>> >        at org.apache.hadoop.io.MapWritable.<init>(MapWritable.java:43)
>> >        at
>> org.apache.nutch.crawl.CrawlDatum.readFields(CrawlDatum.java:260)
>> >        at
>> >
>> >
>> org.apache.hadoop.io.serializer.WritableSerialization$WritableDeserializer.deserialize(WritableSerialization.java:67)
>> >        at
>> >
>> >
>> org.apache.hadoop.io.serializer.WritableSerialization$WritableDeserializer.deserialize(WritableSerialization.java:40)
>> >        at
>> >
>> org.apache.hadoop.mapred.Task$ValuesIterator.readNextValue(Task.java:940)
>> >        at
>> org.apache.hadoop.mapred.Task$ValuesIterator.next(Task.java:880)
>> >        at
>> >
>> >
>> org.apache.hadoop.mapred.ReduceTask$ReduceValuesIterator.moveToNext(ReduceTask.java:237)
>> >        at
>> >
>> >
>> org.apache.hadoop.mapred.ReduceTask$ReduceValuesIterator.next(ReduceTask.java:233)
>> >        at
>> > org.apache.nutch.crawl.CrawlDbReducer.reduce(CrawlDbReducer.java:70)
>> >        at
>> > org.apache.nutch.crawl.CrawlDbReducer.reduce(CrawlDbReducer.java:35)
>> >        at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:436)
>> >        at org.apache.hadoop.mapred.Child.main(Child.java:158)
>> >
>> >
>> > java.lang.OutOfMemoryError: Java heap space
>> >        at
>> > java.util.concurrent.locks.ReentrantLock.<init>(ReentrantLock.java:234)
>> >        at
>> >
>> >
>> java.util.concurrent.ConcurrentHashMap$Segment.<init>(ConcurrentHashMap.java:289)
>> >        at
>> >
>> java.util.concurrent.ConcurrentHashMap.<init>(ConcurrentHashMap.java:613)
>> >        at
>> >
>> java.util.concurrent.ConcurrentHashMap.<init>(ConcurrentHashMap.java:652)
>> >        at
>> >
>> >
>> org.apache.hadoop.io.AbstractMapWritable.<init>(AbstractMapWritable.java:46)
>> >        at org.apache.hadoop.io.MapWritable.<init>(MapWritable.java:42)
>> >        at org.apache.hadoop.io.MapWritable.<init>(MapWritable.java:52)
>> >        at org.apache.nutch.crawl.CrawlDatum.set(CrawlDatum.java:321)
>> >        at
>> > org.apache.nutch.crawl.CrawlDbReducer.reduce(CrawlDbReducer.java:96)
>> >        at
>> > org.apache.nutch.crawl.CrawlDbReducer.reduce(CrawlDbReducer.java:35)
>> >        at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:436)
>> >        at org.apache.hadoop.mapred.Child.main(Child.java:158)
>> >
>> > =====================================================================
>> > hadoop-env.sh
>> >
>> > # Set Hadoop-specific environment variables here.
>> > # The only required environment variable is JAVA_HOME.  All others are
>> > # optional.  When running a distributed configuration it is best to
>> > # set JAVA_HOME in this file, so that it is correctly defined on
>> > # remote nodes.
>> > # The java implementation to use.  Required.
>> > # export JAVA_HOME=/usr/lib/j2sdk1.5-sun
>> > export JAVA_HOME=/usr/lib/jvm/java-6-sun
>> > export HADOOP_HOME=/home/had/nutch-1.0
>> > export HADOOP_CONF_DIR=/home/had/nutch-1.0/conf
>> > export HADOOP_LOG_DIR=/home/had/nutch-1.0/logs
>> > export NUTCH_HOME=/home/had/nutch-1.0
>> > export NUTCH_CONF_DIR=/home/had/nutch-1.0/conf
>> > # Extra Java CLASSPATH elements.  Optional.
>> > # export HADOOP_CLASSPATH=
>> > # The maximum amount of heap to use, in MB. Default is 1000.
>> > export HADOOP_HEAPSIZE=4000
>> > export NUTCH_HEAPSIZE=4000
>> >
>> >
>> ==========================================================================
>> >
>> > hadoop-site.xml
>> >
>> > <?xml version="1.0"?>
>> > <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
>> > <!-- Put site-specific property overrides in this file. -->
>> > <configuration>
>> > <property>
>> >  <name>fs.default.name</name>
>> >  <value>hdfs://distributed1:9000/</value>
>> >  <description>The name of the default file system. Either the literal
>> > string "local" or a host:port for DFS.</description>
>> > </property>
>> > <property>
>> >  <name>mapred.job.tracker</name>
>> >  <value>distributed1:9001</value>
>> >  <description>The host and port that the MapReduce job tracker runs at.
>> If
>> > "local", then jobs are run in-process as a single map and reduce
>> > task.</description>
>> > </property>
>> > <property>
>> >  <name>mapred.tasktracker.tasks.maximum</name>
>> >  <value>2</value>
>> >  <description>
>> >    The maximum number of tasks that will be run simultaneously by
>> >    a task tracker. This should be adjusted according to the heap size
>> >    per task, the amount of RAM available, and CPU consumption of each
>> task.
>> >  </description>
>> > </property>
>> > <property>
>> >  <name>mapred.map.tasks</name>
>> >  <value>799</value>
>> >  <description>
>> >    This should be a prime number larger than multiple number of slave
>> > hosts,
>> >    e.g. for 3 nodes set this to 17
>> >  </description>
>> > </property>
>> > <property>
>> >  <name>io.file.buffer.size</name>
>> >  <value>131072</value>(test  set this value to 4096, but make no
>> > difference)
>> >  <description>The size of buffer for use in sequence files.
>> >  The size of this buffer should probably be a multiple of hardware
>> >  page size (4096 on Intel x86), and it determines how much data is
>> >  buffered during read and write operations.</description>
>> > </property>
>> > <property>
>> >  <name>mapred.reduce.tasks</name>
>> >  <value>29</value>
>> >  <description>
>> >    This should be a prime number close to a low multiple of slave hosts,
>> >    e.g. for 3 nodes set this to 7
>> >  </description>
>> > </property>
>> >
>> > <property>
>> >  <name>hadoop.tmp.dir</name>
>> >  <value>/home/had/nutch-1.0/tmp</value>
>> >  <description>A base for other temporary directories.</description>
>> > </property>
>> > <property>
>> >  <name>dfs.name.dir</name>
>> >  <value>/home/had/nutch-1.0/filesystem/name</value>
>> >  <description>Determines where on the local filesystem the DFS name node
>> > should store the name table. If this is a comma-delimited list of
>> > directories then the name table is replicated in all of the directories,
>> > for
>> > redundancy. </description>
>> > </property>
>> > <property>
>> >  <name>dfs.data.dir</name>
>> >  <value>/home/had/nutch-1.0/filesystem/data</value>
>> >  <description>Determines where on the local filesystem an DFS data node
>> > should store its blocks. If this is a comma-delimited list of
>> directories,
>> > then data will be stored in all named directories, typically on
>> different
>> > devices. Directories that do not exist are ignored.</description>
>> > </property>
>> > <property>
>> >  <name>dfs.replication</name>
>> >  <value>1</value>
>> >  <description>Default block replication. The actual number of
>> replications
>> > can be specified when the file is created. The default is used if
>> > replication is not specified in create time.</description>
>> > </property>
>> > <property>
>> >  <name>mapred.child.java.opts</name>
>> >  <value>-Xmx1000m</value>
>> >  <description>
>> >    You can specify other Java options for each map or reduce task here,
>> >    but most likely you will want to adjust the heap size.
>> >  </description>
>> > </property>
>> > <property>
>> >  <name>mapred.system.dir</name>
>> >  <value>/home/had/nutch-1.0/filesystem/mapreduce/system</value>
>> > </property>
>> > <property>
>> >  <name>mapred.local.dir</name>
>> >  <value>/home/had/nutch-1.0/filesystem/mapreduce/local</value>
>> > </property>
>> >
>> > </configuration>
>> > ====================================================================
>> >
>>
>>
>>
>> --
>> DigitalPebble Ltd
>> http://www.digitalpebble.com
>>
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