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From Harsh J <ha...@cloudera.com>
Subject Re: Counters that track the max value
Date Wed, 03 Oct 2012 16:52:55 GMT

Here's my shot at it (pardon the quick crappy code):

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 <jeremy@lewi.us> 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

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