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From Arshak Navruzyan <>
Subject Re: schema examples
Date Sat, 28 Dec 2013 01:01:03 GMT

Wow, didn't expect to get help from the author :)

How about something simple like this:

Machine    Pool      Load        ReadingTimestamp
neptune     west      5            1388191975000
neptune     west      9            1388191975010
pluto         east       13           1388191975090

These are the areas I am unclear on:

1.  Should the transpose table be built as part of ingest code or as an
accumulo combiner?
2.  What does the degree table do in this example ?  The paper mentions
it's useful for query optimization.  How?
3.  Does D4M accommodate "repurposing" the row_id to a partition key?  The
wikisearch shows how the partition id is important for parallel scans of
the index.  But since Accumulo is a row store how can you do fast lookups
by row if you've used the row_id as a partition key.

Thank you,


On Thu, Dec 26, 2013 at 5:31 PM, Jeremy Kepner <> wrote:

> Hi Arshak,
>   Maybe you can send a few (~3) records of data that you are familiar with
> and we can walk you through how the D4M schema would be applied to those
> records.
> Regards.  -Jeremy
> On Thu, Dec 26, 2013 at 03:10:59PM -0500, Arshak Navruzyan wrote:
> >    Hello,
> >    I am trying to get my head around Accumulo schema designs.  I went
> through
> >    a lot of trouble to get the wikisearch example running but since the
> data
> >    in protobuf lists, it's not that illustrative (for a newbie).
> >    Would love to find another example that is a little simpler to
> understand.
> >     In particular I am interested in java/scala code that mimics the D4M
> >    schema design (not a Matlab guy).
> >    Thanks,
> >    Arshak

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