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From Andrey Kuprianov <andrey.koupria...@gmail.com>
Subject Re: Distinct values with range
Date Mon, 15 Apr 2013 05:10:54 GMT
Thanks. I'll try the lists. Completely forgot about them actually



On Mon, Apr 15, 2013 at 12:59 PM, Jim Klo <jim.klo@sri.com> wrote:

> Not sure if its ideal but if you need dates in epoch millis, you could
> round the timestamp to the floor of the current day (say midnight) in a map
> function, use a built in reduce... Then use a list function to filter
> unique countries.
>
> If you don't need a real timestamp value, use an integer like YYYYMMDD
> (i.e. 20130710 for 2013-Jul-10).
>
> Reduce = true will combine by day making at most (196 countries x number
> of days in range) to filter in the show function.
>
> - JK
>
>
>
> Sent from my iPad
>
> On Apr 14, 2013, at 6:38 PM, "Andrey Kuprianov" <
> andrey.kouprianov@gmail.com> wrote:
>
> > Hi guys,
> >
> > Just for the sake of a debate. Here's the question. There are
> transactions.
> > Among all other attributes there's timestamp (when transaction was made;
> in
> > seconds) and a country name  (from where the transaction was made). So,
> for
> > instance,
> >
> > {
> >    . . . .
> >    "timestamp": 1332806400
> >    "country_name": "Australia",
> >    . . . .
> > }
> >
> > Question is: how does one get unique / distinct country names in between
> > dates? For example, give me all country names in between 10-Jul-2010 and
> > 21-Jan-2013.
> >
> > My solution was to write a custom reduce function and set
> > reduce_limit=false, so that i can enumerate all countries without hitting
> > the overflow exception. It works great! However, such solutions are
> frowned
> > upon by everyone around. Has anyone a better idea on how to tackle this
> > efficiently?
> >
> >    Andrey
>

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