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https://issues.apache.org/jira/browse/HBASE-11900?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Anoop Sam John updated HBASE-11900:
-----------------------------------
    Component/s: mapreduce

> Optimization for incremental load reducer
> -----------------------------------------
>
>                 Key: HBASE-11900
>                 URL: https://issues.apache.org/jira/browse/HBASE-11900
>             Project: HBase
>          Issue Type: Improvement
>          Components: HFile, mapreduce
>    Affects Versions: 0.98.6
>            Reporter: Yi Deng
>            Priority: Minor
>
> In current implementation, the key of reducer configured by 
> HFileOutputFormat.configureIncrementalLoad, is row. So, the reducer has to do 
> an in-memory sort before writing key values to the disk.  When we meet with 
> some rows with a huge number of comlumns/versions, there could be OOM.
> A better way is:
> Use the KeyValue as the key, value can be a NullWritable. Partioner 
> partitions the KeyValue only by it's row part. Set a sort comparator that 
> sort KeyValue with KeyValue.COMPARATOR



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