[jira] Commented: (CHUKWA-481) Improve demux reducer partitioning algorithm

["Bill Graham (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CHUKWA-481?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12867624#action_12867624 ] 

Bill Graham commented on CHUKWA-481:
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I agree that being able to configure the default partitioner like we currently do with the default mapper/reducer would be best. That way whatever is decided to be the hard-coded 'reasonable default' can be overriden in configs. Being able to configure partitioner-per-dataType isn't a use case for us. If we choose not so support it now, we should at lease leave the configuration model open to support it in the future.

> Improve demux reducer partitioning algorithm
> --------------------------------------------
>
>                 Key: CHUKWA-481
>                 URL: https://issues.apache.org/jira/browse/CHUKWA-481
>             Project: Hadoop Chukwa
>          Issue Type: Improvement
>          Components: MR Data Processors
>         Environment: Redhat EL 5.1, Java 6
>            Reporter: Eric Yang
>            Assignee: Eric Yang
>
> Reducer partitioning for demux could be redefined to optimize for two different use case:
> Case #1, demux is responsible for crunching large volumes of the same data type (dozen of types).  It will probably make more sense to partition the reducer by time grouping + data type (extend TotalOrderPartitioner).  I.e. A user can have evenly distributed workload for each reducer base on time interval.  A distributed hash table like Hbase/voldermort could be the down stream system to store/cache the data for data serving.  This model is great for collecting fixed time interval logs like hadoop metrics, and ExecAdaptor which generates repetitive time series summary.
>  
> Case #2, demux is responsible for crunching hundred of different data type, but small volumn for each data type.  The current demux implementation is using this model, where a single data type is reduced by one reducer slot (ChukwaRecordPartitioner).  One draw back from this model,the data from each data type must have similar volume.  Otherwise, the largest data volume type becomes the long tail of the mapreduce job.  Materialized report is easy to generate by using this model because the single reducer per data type has view to all data of the given demux run.  This model works great for many different application and all logging through Chukwa Log4j appender.  I.e. web crawl, or log file indexing / viewing.
>  
> I am thinking to change the default Chukwa demux implementation to case #1, and restructure the current demux as Archive Organizer.  Any suggestion or objection?

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