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From Arshak Navruzyan <arsh...@gmail.com>
Subject Re: unique list of columns
Date Sat, 22 Feb 2014 20:32:22 GMT
Mike,

Thanks; this sounds promising.

Arshak
On Feb 22, 2014 11:48 AM, "Mike Drob" <madrob@cloudera.com> wrote:

> There's not a single good way that I am aware of, but there are a couple
> ways that will get you close.
>
> First, you can use the SortedKeyIterator to truncate values and
> potentially save yourself a lot of data transfer.
> Second, each RFile header block will track the columns contained, up to
> 1000 (possibly configurable). Check out PrintInfo[1].
>
> Mike
>
> [1]:
> https://github.com/apache/accumulo/blob/master/core/src/main/java/org/apache/accumulo/core/file/rfile/PrintInfo.java
>
>
> On Sat, Feb 22, 2014 at 11:25 AM, Arshak Navruzyan <arshakn@gmail.com>wrote:
>
>> I don't know the inner workings of the Rfiles enough but I was wondering
>> if there is a faster way to get a unique list of columns in Accumulo (short
>> of doing a full mapreduce).  Is there some way to skip ahead all the
>> volumes and just get to the next column?
>>
>> Thanks
>>
>
>

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