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Posted to issues@hbase.apache.org by "Nick Dimiduk (JIRA)" <ji...@apache.org> on 2013/03/04 23:37:12 UTC

[jira] [Updated] (HBASE-7743) Replace *SortReducers with Hadoop Secondary Sort

     [ https://issues.apache.org/jira/browse/HBASE-7743?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Nick Dimiduk updated HBASE-7743:
--------------------------------

    Summary: Replace *SortReducers with Hadoop Secondary Sort  (was: KeyValueSortReducer and PutSortReducers buffer entire value-groups in memory)
    
> Replace *SortReducers with Hadoop Secondary Sort
> ------------------------------------------------
>
>                 Key: HBASE-7743
>                 URL: https://issues.apache.org/jira/browse/HBASE-7743
>             Project: HBase
>          Issue Type: Improvement
>          Components: mapreduce, Performance
>            Reporter: Nick Dimiduk
>
> The mapreduce package provides two Reducer implementations, KeyValueSortReducer and PutSortReducer, which are used by Import, ImportTsv, and WALPlayer in conjunction with the HFileOutputFormat. Both of these implementations make use of a TreeSet to sort values matching a key. This reducer will OOM when rows are large.
> A better solution would be to implement secondary sort of the values. That way hadoop sorts the records, spilling to disk when necessary.

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