You are viewing a plain text version of this content. The canonical link for it is here.

Posted to mapreduce-issues@hadoop.apache.org by "stanley shi (JIRA)" <ji...@apache.org> on 2013/11/25 06:32:35 UTC

[jira] [Created] (MAPREDUCE-5649) Reduce cannot use more than 2G memory for the final merge

stanley shi created MAPREDUCE-5649:
--------------------------------------

             Summary: Reduce cannot use more than 2G memory  for the final merge
                 Key: MAPREDUCE-5649
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5649
             Project: Hadoop Map/Reduce
          Issue Type: Bug
          Components: mrv2
    Affects Versions: trunk
            Reporter: stanley shi


In the org.apache.hadoop.mapreduce.task.reduce.MergeManagerImpl.java file, in the finalMerge method: 

 int maxInMemReduce = (int)Math.min(
        Runtime.getRuntime().maxMemory() * maxRedPer, Integer.MAX_VALUE);
 
This means no matter how much memory user has, reducer will not retain more than 2G data in memory before the reduce phase starts.




--
This message was sent by Atlassian JIRA
(v6.1#6144)