You are right
Actually we were expecting the values to be sorted.
We tried to reproduce the problem by this simple code
private final IntWritable one=new IntWritable(1);
private Text word=new Text();
@Override
public void map(LongWritable key,Text value, Context context) throws
IOException, InterruptedException {
int N=30000;
for(int i=0;i<N;i++)
{
word.set(i+"");
System.out.println(i);
context.write(one,word);
}
}
For smaller N numbers were in order but for N 3000000 order was not maintained
From: Harsh J [mailto:[email protected]]
Sent: Thursday, January 17, 2013 1:57 AM
To: mapreduce-user
Subject: RE: Limitation of key-value pairs for a particular key.
We don't sort values (only keys) nor apply any manual limits in MR. Can your
post a reproduceable test case to support your suspicion?
On Jan 16, 2013 4:34 PM, "Utkarsh Gupta"
<[email protected]<mailto:[email protected]>> wrote:
Hi,
Thanks for the response. There was some issues with my code. I have checked
that in detail.
All the values of map are present in reducer but not in sorted order. This case
happens if the number of values are too large for a key.
Thanks
Utkarsh
From: Vinod Kumar Vavilapalli
[mailto:[email protected]<mailto:[email protected]>]
Sent: Thursday, January 10, 2013 11:00 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: Limitation of key-value pairs for a particular key.
There isn't any limit like that. Can you reproduce this consistently? If so,
please file a ticket.
It will definitely help if you can provide a test case which can reproduce this
issue.
Thanks,
+Vinod
On Thu, Jan 10, 2013 at 12:41 AM, Utkarsh Gupta
<[email protected]<mailto:[email protected]>> wrote:
Hi,
I am using Apache Hadoop 1.0.4 on a 10 node cluster of commodity machines with
Ubuntu 12.04 Server edition. I am having a issue with my map reduce code. While
debugging I found that the reducer can take 262145 values for a particular key.
If more values are there, they seem to be corrupted. I checked the values while
emitting from map and again checked in reducer.
I am wondering is there any such kind of limitation in the Hadoop or is it a
configuration problem.
Thanks and Regards
Utkarsh Gupta
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