Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
MapReduce >> mail # user >> Counters that track the max value

Copy link to this message
Re: Counters that track the max value
HI Harsh,

Thank you very much that will work.

How come we can't simply create a modification of a regular mapreduce
counter which does this behind the scenes? It seems like we should just be
able to replace "+" with "max" and everything else should work?


On Wed, Oct 3, 2012 at 9:52 AM, Harsh J <[EMAIL PROTECTED]> wrote:

> Jeremy,
> Here's my shot at it (pardon the quick crappy code):
> https://gist.github.com/3828246
> Basically - you can achieve it in two ways:
> Requirement:  All tasks must increment the "max" designated counter
> only AFTER the max has been computed (i.e. in cleanup).
> 1. All tasks may use same counter name. Later, we pull per-task
> counters and determine the max at the client. (This is my quick and
> dirty implementation)
> 2. All tasks may use their own task ID (Number part) in the counter
> name, but use the same group. Later, we fetch all counters for that
> group and iterate over it to find the max. This is cleaner, and
> doesn't end up using deprecated APIs such as the above.
> Does this help?
> On Wed, Oct 3, 2012 at 8:47 PM, Jeremy Lewi <[EMAIL PROTECTED]> wrote:
> > HI hadoop-users,
> >
> > I'm curious if there is an implementation somewhere of a counter which
> > tracks the maximum of some value across all mappers or reducers?
> >
> > Thanks
> > J
> --
> Harsh J