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From William Oberman <ober...@civicscience.com>
Subject Re: hadoop results
Date Thu, 30 Jun 2011 11:51:16 GMT
I think I'll do the former, thanks!

On Wed, Jun 29, 2011 at 11:16 PM, aaron morton <aaron@thelastpickle.com>wrote:

> How about  get_slice() with reversed == true and count = 1 to get the
> highest time UUID ?
>
> Or you can also store a column with a magic name that have the value of the
> timeuuid that is the current metric to use.
>
> Cheers
>
> -----------------
> Aaron Morton
> Freelance Cassandra Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 30 Jun 2011, at 06:35, William Oberman wrote:
>
> > I'll start with my question: given a CF with comparator TimeUUIDType,
> what is the most efficient way to get the greatest column's value?
> >
> > Context: I've been running cassandra for a couple of months now, so
> obviously it's time to start layering more on top :-)  In my test
> environment, I managed to get pig/hadoop running, and developed a few
> scripts to collect metrics I've been missing since I switched from MySQL to
> cassandra (including the ever useful "select count(*) from table"
> equivalent).
> >
> > I was hoping to dump the results of this processing back into cassandra
> for use in other tools/processes.  My initial thought was: new CF called
> "stats" with comparator TimeUUIDType.  The basic idea being I'd store:
> > stat_name -> time stat was computed (as UUID) -> value
> > That way I can also see a historical perspective of any given stat for
> auditing (and for cumulative stats to see trends).  The stat_name itself is
> a URI that is composed of "what" and any constraints on the "what"
> (including an optional time range, if the stat supports it).  E.g.
> ClassOfSomething/ID/MetricName/OptionalTimeRange (or something, still
> deciding on the format of the URI).  But, right now, the only way I know to
> get the "current" stat value would be to iterate over all columns (the
> TimeUUIDs) and then return the last one.
> >
> > Thanks for any tips,
> >
> > will
>
>


-- 
Will Oberman
Civic Science, Inc.
3030 Penn Avenue., First Floor
Pittsburgh, PA 15201
(M) 412-480-7835
(E) oberman@civicscience.com

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