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Posted to common-user@hadoop.apache.org by Apurva Jadhav <aj...@thefind.com> on 2008/04/23 08:40:25 UTC

reducer outofmemoryerror

Hi,
  I have a 4 node hadoop 0.15.3 cluster. I am using the default config 
files. I am running a map reduce job to process 40 GB log data.
Some reduce tasks are failing with the following errors:
1)
stderr
Exception in thread "org.apache.hadoop.io.ObjectWritable Connection 
Culler" Exception in thread 
"org.apache.hadoop.dfs.DFSClient$LeaseChecker@1b3f8f6" 
java.lang.OutOfMemoryError: Java heap space
Exception in thread "IPC Client connection to /127.0.0.1:34691" 
java.lang.OutOfMemoryError: Java heap space
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space

2)
stderr
 Exception in thread "org.apache.hadoop.io.ObjectWritable Connection 
Culler" java.lang.OutOfMemoryError: Java heap space

syslog:
2008-04-22 19:32:50,784 INFO org.apache.hadoop.mapred.ReduceTask: 
task_200804212359_0007_r_000004_0 Merge of the 19 files in 
InMemoryFileSystem complete. Local file is /data/hadoop-im2/mapred/loca
l/task_200804212359_0007_r_000004_0/map_22600.out
2008-04-22 20:34:16,012 INFO org.apache.hadoop.ipc.Client: 
java.net.SocketException: Socket closed
        at java.net.SocketInputStream.read(SocketInputStream.java:162)
        at java.io.FilterInputStream.read(FilterInputStream.java:111)
        at org.apache.hadoop.ipc.Client$Connection$1.read(Client.java:181)
        at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
        at java.io.BufferedInputStream.read(BufferedInputStream.java:235)
        at java.io.DataInputStream.readInt(DataInputStream.java:353)
        at org.apache.hadoop.ipc.Client$Connection.run(Client.java:258)

2008-04-22 20:34:16,032 WARN org.apache.hadoop.mapred.TaskTracker: Error 
running child
java.lang.OutOfMemoryError: Java heap space
2008-04-22 20:34:16,031 INFO org.apache.hadoop.mapred.TaskRunner: 
Communication exception: java.lang.OutOfMemoryError: Java heap space

Has anyone experienced similar problem ?   Is there any configuration 
change that can help resolve this issue.

Regards,
aj




Re: reducer outofmemoryerror

Posted by Apurva Jadhav <aj...@thefind.com>.
I made two changes:
1) Increased mapred.child.java opts tp 768m
2) Coalesced the files into smaller number of larger files.

This has resolved my problem and reduced the running time by a factor of 3.

Thanks for all the suggestions.


Ted Dunning wrote:
> If these files are small, you will have a significant (but not massive) hit
> in performance due to having so many files.
>
>
> On 4/24/08 12:07 AM, "Arun C Murthy" <ar...@yahoo-inc.com> wrote:
>
>   
>> On Apr 23, 2008, at 7:51 AM, Apurva Jadhav wrote:
>>
>>     
>>> There are six reducers and 24000 mappers because there are 24000
>>> files.
>>> The number of tasks per node is 2.
>>> mapred.child.java opts is the default value 200m. What is a good
>>> value for this.? My mappers and reducers are fairly simple and do
>>> not make large allocations.
>>>       
>> Try upping that to 512M.
>>
>> Arun
>>
>>     
>>> Regards,
>>> aj
>>>
>>> Amar Kamat wrote:
>>>       
>>>> Apurva Jadhav wrote:
>>>>         
>>>>> Hi,
>>>>>  I have a 4 node hadoop 0.15.3 cluster. I am using the default
>>>>> config files. I am running a map reduce job to process 40 GB log
>>>>> data.
>>>>>           
>>>> How many maps and reducers are there? Make sure that there are
>>>> sufficient number of reducers. Look at conf/hadoop-default.xml
>>>> (see mapred.child.java.opts parameter) to change the heap settings.
>>>> Amar
>>>>         
>>>>> Some reduce tasks are failing with the following errors:
>>>>> 1)
>>>>> stderr
>>>>> Exception in thread "org.apache.hadoop.io.ObjectWritable
>>>>> Connection Culler" Exception in thread
>>>>> "org.apache.hadoop.dfs.DFSClient$LeaseChecker@1b3f8f6"
>>>>> java.lang.OutOfMemoryError: Java heap space
>>>>> Exception in thread "IPC Client connection to /127.0.0.1:34691"
>>>>> java.lang.OutOfMemoryError: Java heap space
>>>>> Exception in thread "main" java.lang.OutOfMemoryError: Java heap
>>>>> space
>>>>>
>>>>> 2)
>>>>> stderr
>>>>> Exception in thread "org.apache.hadoop.io.ObjectWritable
>>>>> Connection Culler" java.lang.OutOfMemoryError: Java heap space
>>>>>
>>>>> syslog:
>>>>> 2008-04-22 19:32:50,784 INFO org.apache.hadoop.mapred.ReduceTask:
>>>>> task_200804212359_0007_r_000004_0 Merge of the 19 files in
>>>>> InMemoryFileSystem complete. Local file is /data/hadoop-im2/
>>>>> mapred/loca
>>>>> l/task_200804212359_0007_r_000004_0/map_22600.out
>>>>> 2008-04-22 20:34:16,012 INFO org.apache.hadoop.ipc.Client:
>>>>> java.net.SocketException: Socket closed
>>>>>        at java.net.SocketInputStream.read(SocketInputStream.java:
>>>>> 162)
>>>>>        at java.io.FilterInputStream.read(FilterInputStream.java:111)
>>>>>        at org.apache.hadoop.ipc.Client$Connection$1.read
>>>>> (Client.java:181)
>>>>>        at java.io.BufferedInputStream.fill
>>>>> (BufferedInputStream.java:218)
>>>>>        at java.io.BufferedInputStream.read
>>>>> (BufferedInputStream.java:235)
>>>>>        at java.io.DataInputStream.readInt(DataInputStream.java:353)
>>>>>        at org.apache.hadoop.ipc.Client$Connection.run(Client.java:
>>>>> 258)
>>>>>
>>>>> 2008-04-22 20:34:16,032 WARN
>>>>> org.apache.hadoop.mapred.TaskTracker: Error running child
>>>>> java.lang.OutOfMemoryError: Java heap space
>>>>> 2008-04-22 20:34:16,031 INFO org.apache.hadoop.mapred.TaskRunner:
>>>>> Communication exception: java.lang.OutOfMemoryError: Java heap space
>>>>>
>>>>> Has anyone experienced similar problem ?   Is there any
>>>>> configuration change that can help resolve this issue.
>>>>>
>>>>> Regards,
>>>>> aj
>>>>>
>>>>>
>>>>>
>>>>>           
>>>>         
>
>
>   


Re: reducer outofmemoryerror

Posted by Ted Dunning <td...@veoh.com>.
If these files are small, you will have a significant (but not massive) hit
in performance due to having so many files.


On 4/24/08 12:07 AM, "Arun C Murthy" <ar...@yahoo-inc.com> wrote:

> 
> On Apr 23, 2008, at 7:51 AM, Apurva Jadhav wrote:
> 
>> There are six reducers and 24000 mappers because there are 24000
>> files.
>> The number of tasks per node is 2.
>> mapred.child.java opts is the default value 200m. What is a good
>> value for this.? My mappers and reducers are fairly simple and do
>> not make large allocations.
> 
> Try upping that to 512M.
> 
> Arun
> 
>> Regards,
>> aj
>> 
>> Amar Kamat wrote:
>>> Apurva Jadhav wrote:
>>>> Hi,
>>>>  I have a 4 node hadoop 0.15.3 cluster. I am using the default
>>>> config files. I am running a map reduce job to process 40 GB log
>>>> data.
>>> How many maps and reducers are there? Make sure that there are
>>> sufficient number of reducers. Look at conf/hadoop-default.xml
>>> (see mapred.child.java.opts parameter) to change the heap settings.
>>> Amar
>>>> Some reduce tasks are failing with the following errors:
>>>> 1)
>>>> stderr
>>>> Exception in thread "org.apache.hadoop.io.ObjectWritable
>>>> Connection Culler" Exception in thread
>>>> "org.apache.hadoop.dfs.DFSClient$LeaseChecker@1b3f8f6"
>>>> java.lang.OutOfMemoryError: Java heap space
>>>> Exception in thread "IPC Client connection to /127.0.0.1:34691"
>>>> java.lang.OutOfMemoryError: Java heap space
>>>> Exception in thread "main" java.lang.OutOfMemoryError: Java heap
>>>> space
>>>> 
>>>> 2)
>>>> stderr
>>>> Exception in thread "org.apache.hadoop.io.ObjectWritable
>>>> Connection Culler" java.lang.OutOfMemoryError: Java heap space
>>>> 
>>>> syslog:
>>>> 2008-04-22 19:32:50,784 INFO org.apache.hadoop.mapred.ReduceTask:
>>>> task_200804212359_0007_r_000004_0 Merge of the 19 files in
>>>> InMemoryFileSystem complete. Local file is /data/hadoop-im2/
>>>> mapred/loca
>>>> l/task_200804212359_0007_r_000004_0/map_22600.out
>>>> 2008-04-22 20:34:16,012 INFO org.apache.hadoop.ipc.Client:
>>>> java.net.SocketException: Socket closed
>>>>        at java.net.SocketInputStream.read(SocketInputStream.java:
>>>> 162)
>>>>        at java.io.FilterInputStream.read(FilterInputStream.java:111)
>>>>        at org.apache.hadoop.ipc.Client$Connection$1.read
>>>> (Client.java:181)
>>>>        at java.io.BufferedInputStream.fill
>>>> (BufferedInputStream.java:218)
>>>>        at java.io.BufferedInputStream.read
>>>> (BufferedInputStream.java:235)
>>>>        at java.io.DataInputStream.readInt(DataInputStream.java:353)
>>>>        at org.apache.hadoop.ipc.Client$Connection.run(Client.java:
>>>> 258)
>>>> 
>>>> 2008-04-22 20:34:16,032 WARN
>>>> org.apache.hadoop.mapred.TaskTracker: Error running child
>>>> java.lang.OutOfMemoryError: Java heap space
>>>> 2008-04-22 20:34:16,031 INFO org.apache.hadoop.mapred.TaskRunner:
>>>> Communication exception: java.lang.OutOfMemoryError: Java heap space
>>>> 
>>>> Has anyone experienced similar problem ?   Is there any
>>>> configuration change that can help resolve this issue.
>>>> 
>>>> Regards,
>>>> aj
>>>> 
>>>> 
>>>> 
>>> 
>>> 
>> 
> 


Re: reducer outofmemoryerror

Posted by Arun C Murthy <ar...@yahoo-inc.com>.
On Apr 23, 2008, at 7:51 AM, Apurva Jadhav wrote:

> There are six reducers and 24000 mappers because there are 24000  
> files.
> The number of tasks per node is 2.
> mapred.child.java opts is the default value 200m. What is a good  
> value for this.? My mappers and reducers are fairly simple and do  
> not make large allocations.

Try upping that to 512M.

Arun

> Regards,
> aj
>
> Amar Kamat wrote:
>> Apurva Jadhav wrote:
>>> Hi,
>>>  I have a 4 node hadoop 0.15.3 cluster. I am using the default  
>>> config files. I am running a map reduce job to process 40 GB log  
>>> data.
>> How many maps and reducers are there? Make sure that there are  
>> sufficient number of reducers. Look at conf/hadoop-default.xml  
>> (see mapred.child.java.opts parameter) to change the heap settings.
>> Amar
>>> Some reduce tasks are failing with the following errors:
>>> 1)
>>> stderr
>>> Exception in thread "org.apache.hadoop.io.ObjectWritable  
>>> Connection Culler" Exception in thread  
>>> "org.apache.hadoop.dfs.DFSClient$LeaseChecker@1b3f8f6"  
>>> java.lang.OutOfMemoryError: Java heap space
>>> Exception in thread "IPC Client connection to /127.0.0.1:34691"  
>>> java.lang.OutOfMemoryError: Java heap space
>>> Exception in thread "main" java.lang.OutOfMemoryError: Java heap  
>>> space
>>>
>>> 2)
>>> stderr
>>> Exception in thread "org.apache.hadoop.io.ObjectWritable  
>>> Connection Culler" java.lang.OutOfMemoryError: Java heap space
>>>
>>> syslog:
>>> 2008-04-22 19:32:50,784 INFO org.apache.hadoop.mapred.ReduceTask:  
>>> task_200804212359_0007_r_000004_0 Merge of the 19 files in  
>>> InMemoryFileSystem complete. Local file is /data/hadoop-im2/ 
>>> mapred/loca
>>> l/task_200804212359_0007_r_000004_0/map_22600.out
>>> 2008-04-22 20:34:16,012 INFO org.apache.hadoop.ipc.Client:  
>>> java.net.SocketException: Socket closed
>>>        at java.net.SocketInputStream.read(SocketInputStream.java: 
>>> 162)
>>>        at java.io.FilterInputStream.read(FilterInputStream.java:111)
>>>        at org.apache.hadoop.ipc.Client$Connection$1.read 
>>> (Client.java:181)
>>>        at java.io.BufferedInputStream.fill 
>>> (BufferedInputStream.java:218)
>>>        at java.io.BufferedInputStream.read 
>>> (BufferedInputStream.java:235)
>>>        at java.io.DataInputStream.readInt(DataInputStream.java:353)
>>>        at org.apache.hadoop.ipc.Client$Connection.run(Client.java: 
>>> 258)
>>>
>>> 2008-04-22 20:34:16,032 WARN  
>>> org.apache.hadoop.mapred.TaskTracker: Error running child
>>> java.lang.OutOfMemoryError: Java heap space
>>> 2008-04-22 20:34:16,031 INFO org.apache.hadoop.mapred.TaskRunner:  
>>> Communication exception: java.lang.OutOfMemoryError: Java heap space
>>>
>>> Has anyone experienced similar problem ?   Is there any  
>>> configuration change that can help resolve this issue.
>>>
>>> Regards,
>>> aj
>>>
>>>
>>>
>>
>>
>


Re: reducer outofmemoryerror

Posted by Arun C Murthy <ar...@yahoo-inc.com>.
On Apr 23, 2008, at 7:51 AM, Apurva Jadhav wrote:

> There are six reducers and 24000 mappers because there are 24000  
> files.
> The number of tasks per node is 2.
> mapred.child.java opts is the default value 200m. What is a good  
> value for this.? My mappers and reducers are fairly simple and do  
> not make large allocations.

Also, how much RAM do you have on each machine? If you have  
sufficient RAM, 512M is a good value (if you can afford 512*4 i.e. 2  
maps and 2 reduces).

Arun

> Regards,
> aj
>
> Amar Kamat wrote:
>> Apurva Jadhav wrote:
>>> Hi,
>>>  I have a 4 node hadoop 0.15.3 cluster. I am using the default  
>>> config files. I am running a map reduce job to process 40 GB log  
>>> data.
>> How many maps and reducers are there? Make sure that there are  
>> sufficient number of reducers. Look at conf/hadoop-default.xml  
>> (see mapred.child.java.opts parameter) to change the heap settings.
>> Amar
>>> Some reduce tasks are failing with the following errors:
>>> 1)
>>> stderr
>>> Exception in thread "org.apache.hadoop.io.ObjectWritable  
>>> Connection Culler" Exception in thread  
>>> "org.apache.hadoop.dfs.DFSClient$LeaseChecker@1b3f8f6"  
>>> java.lang.OutOfMemoryError: Java heap space
>>> Exception in thread "IPC Client connection to /127.0.0.1:34691"  
>>> java.lang.OutOfMemoryError: Java heap space
>>> Exception in thread "main" java.lang.OutOfMemoryError: Java heap  
>>> space
>>>
>>> 2)
>>> stderr
>>> Exception in thread "org.apache.hadoop.io.ObjectWritable  
>>> Connection Culler" java.lang.OutOfMemoryError: Java heap space
>>>
>>> syslog:
>>> 2008-04-22 19:32:50,784 INFO org.apache.hadoop.mapred.ReduceTask:  
>>> task_200804212359_0007_r_000004_0 Merge of the 19 files in  
>>> InMemoryFileSystem complete. Local file is /data/hadoop-im2/ 
>>> mapred/loca
>>> l/task_200804212359_0007_r_000004_0/map_22600.out
>>> 2008-04-22 20:34:16,012 INFO org.apache.hadoop.ipc.Client:  
>>> java.net.SocketException: Socket closed
>>>        at java.net.SocketInputStream.read(SocketInputStream.java: 
>>> 162)
>>>        at java.io.FilterInputStream.read(FilterInputStream.java:111)
>>>        at org.apache.hadoop.ipc.Client$Connection$1.read 
>>> (Client.java:181)
>>>        at java.io.BufferedInputStream.fill 
>>> (BufferedInputStream.java:218)
>>>        at java.io.BufferedInputStream.read 
>>> (BufferedInputStream.java:235)
>>>        at java.io.DataInputStream.readInt(DataInputStream.java:353)
>>>        at org.apache.hadoop.ipc.Client$Connection.run(Client.java: 
>>> 258)
>>>
>>> 2008-04-22 20:34:16,032 WARN  
>>> org.apache.hadoop.mapred.TaskTracker: Error running child
>>> java.lang.OutOfMemoryError: Java heap space
>>> 2008-04-22 20:34:16,031 INFO org.apache.hadoop.mapred.TaskRunner:  
>>> Communication exception: java.lang.OutOfMemoryError: Java heap space
>>>
>>> Has anyone experienced similar problem ?   Is there any  
>>> configuration change that can help resolve this issue.
>>>
>>> Regards,
>>> aj
>>>
>>>
>>>
>>
>>
>


Re: reducer outofmemoryerror

Posted by Apurva Jadhav <aj...@thefind.com>.
There are six reducers and 24000 mappers because there are 24000 files.
The number of tasks per node is 2.
mapred.child.java opts is the default value 200m. What is a good value 
for this.? My mappers and reducers are fairly simple and do not make 
large allocations.
Regards,
aj

Amar Kamat wrote:
> Apurva Jadhav wrote:
>> Hi,
>>  I have a 4 node hadoop 0.15.3 cluster. I am using the default config 
>> files. I am running a map reduce job to process 40 GB log data.
> How many maps and reducers are there? Make sure that there are 
> sufficient number of reducers. Look at conf/hadoop-default.xml (see 
> mapred.child.java.opts parameter) to change the heap settings.
> Amar
>> Some reduce tasks are failing with the following errors:
>> 1)
>> stderr
>> Exception in thread "org.apache.hadoop.io.ObjectWritable Connection 
>> Culler" Exception in thread 
>> "org.apache.hadoop.dfs.DFSClient$LeaseChecker@1b3f8f6" 
>> java.lang.OutOfMemoryError: Java heap space
>> Exception in thread "IPC Client connection to /127.0.0.1:34691" 
>> java.lang.OutOfMemoryError: Java heap space
>> Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
>>
>> 2)
>> stderr
>> Exception in thread "org.apache.hadoop.io.ObjectWritable Connection 
>> Culler" java.lang.OutOfMemoryError: Java heap space
>>
>> syslog:
>> 2008-04-22 19:32:50,784 INFO org.apache.hadoop.mapred.ReduceTask: 
>> task_200804212359_0007_r_000004_0 Merge of the 19 files in 
>> InMemoryFileSystem complete. Local file is /data/hadoop-im2/mapred/loca
>> l/task_200804212359_0007_r_000004_0/map_22600.out
>> 2008-04-22 20:34:16,012 INFO org.apache.hadoop.ipc.Client: 
>> java.net.SocketException: Socket closed
>>        at java.net.SocketInputStream.read(SocketInputStream.java:162)
>>        at java.io.FilterInputStream.read(FilterInputStream.java:111)
>>        at 
>> org.apache.hadoop.ipc.Client$Connection$1.read(Client.java:181)
>>        at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
>>        at java.io.BufferedInputStream.read(BufferedInputStream.java:235)
>>        at java.io.DataInputStream.readInt(DataInputStream.java:353)
>>        at org.apache.hadoop.ipc.Client$Connection.run(Client.java:258)
>>
>> 2008-04-22 20:34:16,032 WARN org.apache.hadoop.mapred.TaskTracker: 
>> Error running child
>> java.lang.OutOfMemoryError: Java heap space
>> 2008-04-22 20:34:16,031 INFO org.apache.hadoop.mapred.TaskRunner: 
>> Communication exception: java.lang.OutOfMemoryError: Java heap space
>>
>> Has anyone experienced similar problem ?   Is there any configuration 
>> change that can help resolve this issue.
>>
>> Regards,
>> aj
>>
>>
>>
>
>


Re: reducer outofmemoryerror

Posted by Amar Kamat <am...@yahoo-inc.com>.
Apurva Jadhav wrote:
> Hi,
>  I have a 4 node hadoop 0.15.3 cluster. I am using the default config 
> files. I am running a map reduce job to process 40 GB log data.
How many maps and reducers are there? Make sure that there are 
sufficient number of reducers. Look at conf/hadoop-default.xml (see 
mapred.child.java.opts parameter) to change the heap settings.
Amar
> Some reduce tasks are failing with the following errors:
> 1)
> stderr
> Exception in thread "org.apache.hadoop.io.ObjectWritable Connection 
> Culler" Exception in thread 
> "org.apache.hadoop.dfs.DFSClient$LeaseChecker@1b3f8f6" 
> java.lang.OutOfMemoryError: Java heap space
> Exception in thread "IPC Client connection to /127.0.0.1:34691" 
> java.lang.OutOfMemoryError: Java heap space
> Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
>
> 2)
> stderr
> Exception in thread "org.apache.hadoop.io.ObjectWritable Connection 
> Culler" java.lang.OutOfMemoryError: Java heap space
>
> syslog:
> 2008-04-22 19:32:50,784 INFO org.apache.hadoop.mapred.ReduceTask: 
> task_200804212359_0007_r_000004_0 Merge of the 19 files in 
> InMemoryFileSystem complete. Local file is /data/hadoop-im2/mapred/loca
> l/task_200804212359_0007_r_000004_0/map_22600.out
> 2008-04-22 20:34:16,012 INFO org.apache.hadoop.ipc.Client: 
> java.net.SocketException: Socket closed
>        at java.net.SocketInputStream.read(SocketInputStream.java:162)
>        at java.io.FilterInputStream.read(FilterInputStream.java:111)
>        at org.apache.hadoop.ipc.Client$Connection$1.read(Client.java:181)
>        at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
>        at java.io.BufferedInputStream.read(BufferedInputStream.java:235)
>        at java.io.DataInputStream.readInt(DataInputStream.java:353)
>        at org.apache.hadoop.ipc.Client$Connection.run(Client.java:258)
>
> 2008-04-22 20:34:16,032 WARN org.apache.hadoop.mapred.TaskTracker: 
> Error running child
> java.lang.OutOfMemoryError: Java heap space
> 2008-04-22 20:34:16,031 INFO org.apache.hadoop.mapred.TaskRunner: 
> Communication exception: java.lang.OutOfMemoryError: Java heap space
>
> Has anyone experienced similar problem ?   Is there any configuration 
> change that can help resolve this issue.
>
> Regards,
> aj
>
>
>


Re: reducer outofmemoryerror

Posted by Harish Mallipeddi <ha...@gmail.com>.
Memory settings are in conf/hadoop-default.xml. You can override them in
conf/hadoop-site.xml.

Specifically I think you would want to change mapred.child.java.opts

On Wed, Apr 23, 2008 at 2:40 PM, Apurva Jadhav <aj...@thefind.com> wrote:

> Hi,
>  I have a 4 node hadoop 0.15.3 cluster. I am using the default config
> files. I am running a map reduce job to process 40 GB log data.
> Some reduce tasks are failing with the following errors:
> 1)
> stderr
> Exception in thread "org.apache.hadoop.io.ObjectWritable Connection
> Culler" Exception in thread
> "org.apache.hadoop.dfs.DFSClient$LeaseChecker@1b3f8f6"
> java.lang.OutOfMemoryError: Java heap space
> Exception in thread "IPC Client connection to /127.0.0.1:34691"
> java.lang.OutOfMemoryError: Java heap space
> Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
>
> 2)
> stderr
> Exception in thread "org.apache.hadoop.io.ObjectWritable Connection
> Culler" java.lang.OutOfMemoryError: Java heap space
>
> syslog:
> 2008-04-22 19:32:50,784 INFO org.apache.hadoop.mapred.ReduceTask:
> task_200804212359_0007_r_000004_0 Merge of the 19 files in
> InMemoryFileSystem complete. Local file is /data/hadoop-im2/mapred/loca
> l/task_200804212359_0007_r_000004_0/map_22600.out
> 2008-04-22 20:34:16,012 INFO org.apache.hadoop.ipc.Client:
> java.net.SocketException: Socket closed
>       at java.net.SocketInputStream.read(SocketInputStream.java:162)
>       at java.io.FilterInputStream.read(FilterInputStream.java:111)
>       at org.apache.hadoop.ipc.Client$Connection$1.read(Client.java:181)
>       at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
>       at java.io.BufferedInputStream.read(BufferedInputStream.java:235)
>       at java.io.DataInputStream.readInt(DataInputStream.java:353)
>       at org.apache.hadoop.ipc.Client$Connection.run(Client.java:258)
>
> 2008-04-22 20:34:16,032 WARN org.apache.hadoop.mapred.TaskTracker: Error
> running child
> java.lang.OutOfMemoryError: Java heap space
> 2008-04-22 20:34:16,031 INFO org.apache.hadoop.mapred.TaskRunner:
> Communication exception: java.lang.OutOfMemoryError: Java heap space
>
> Has anyone experienced similar problem ?   Is there any configuration
> change that can help resolve this issue.
>
> Regards,
> aj
>
>
>
>


-- 
Harish Mallipeddi
circos.com : poundbang.in/blog/