Hi
Suppose that your input file are 10 with total size 64mb , I think you will
get the 10 maps.
By the ways,the uber mode is only for yarn . Suppose you have actually 1
map ,yarn will at least create two containers , one for app master and the
other for the map , if uber mode is enabled with the yarn , yarn will only
create 1 container for both app master and the map.
发自我的 iPhone
在 2013-5-6，22:45，Rahul Bhattacharjee <[email protected]> 写道：
> Hi,
>
> I was going through the definition of Uber Job of Hadoop.
>
> A job is considered uber when it has 10 or less maps , one reducer and the
> complete data is less than one dfs block size.
>
> I have some doubts here-
>
> Splits are created as per the dfs block size.Creating 10 mappers are possible
> from one block of data by some settings change (changing the max split size).
> But trying to understand , why would some job need to run around 10 maps for
> 64 MB of data.
> One thing may be that the job is immensely CUP intensive. Will it be a
> correct assumption? or is there is any other reason for this.
>
> Thanks,
> Rahul
>
>
