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From William Slacum <wilhelm.von.cl...@accumulo.net>
Subject Re: How to efficiently find lexicographically adjacent records?
Date Wed, 07 Aug 2013 21:40:42 GMT
Finding the keys after your hypothetical key is easy, as you can just make
it the first key in the range you pass to your Scanner. Since accumulo
doesn't do backwards scanning, you might have to consider having two tables
or sets of rows, one that sorts lexicographically and the other that sorts
in reverse lexicographic order.

There's also probably trickery you can do with the key extents and buffered
reading in an iterator to avoid having to write your data twice. I think it
would involve picking a tablet that would contain your key and expanding
your scans if you don't have enough data.


On Wed, Aug 7, 2013 at 5:31 PM, Jeff Kubina <jeff.kubina@gmail.com> wrote:

> I have records <key; value> in an Accumulo table where the key is about a
> 50 long byte string. Given a new key k, I want to find the m records that
> would precede and succeed the record <k;v> if it were inserted into the
> table. Any ideas on how I can do this efficiently? The record <k;v> will
> eventually be inserted into the table.
>
> -Jeff
>
>

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