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From John Vines <vi...@apache.org>
Subject Re: unique list of columns
Date Sat, 22 Feb 2014 16:52:01 GMT
To expand on that, the index block(s)  will have all column family info if
you just care about today.

Sent from my phone, please pardon the typos and brevity.
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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