How to set the number of mappers for TableInputFormat

[zhangshuai01 <zh...@ict.ac.cn>]

hi,all!


well all knows that bloksize and filesplit control the number of mappers(in hadoop-0.20.2). 


But when using the HBASE as input, how is the number of mappers decided?


thanks a lot!


Shuai Zhang

Re: How to set the number of mappers for TableInputFormat

["Brush,Ryan" <RB...@CERNER.COM>]

This may be more appropriate for the user@hbase.apache.org list, but I
believe the post at [1] is still accurate.  In short, there is one split
per region, which makes sense because there isn't another good way (that
I'm aware of) to locate keys for the start and stop of the scan used by
each map task.

[1]
http://www.larsgeorge.com/2009/01/how-to-use-hbase-with-hadoop.html


On 8/15/11 9:16 AM, "zhangshuai01" <zh...@ict.ac.cn> wrote:

>hi,all!
>
>
>well all knows that bloksize and filesplit control the number of
>mappers(in hadoop-0.20.2).
>
>
>But when using the HBASE as input, how is the number of mappers decided?
>
>
>thanks a lot!
>
>
>Shuai Zhang

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