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From Josh Elser <>
Subject Re: schema examples
Date Sat, 28 Dec 2013 15:52:29 GMT
On 12/28/2013 12:53 AM, Dylan Hutchison wrote:
> /1.  Should the transpose table be built as part of ingest code or as an
> accumulo combiner?/
> I recommend ingest code for much greater simplicity, though it may be
> possible to build a combiner to automatically ingest to a second table.
>   When inserting (row,col,val) triples, do another insert to the
> transpose with (col,row,val).
> Use summing combiners to create the degree tables.

Using a combiner is likely to be much more hassle than it's worth. When 
your Combiner gets invoked server-side, you have no notion of lifecycle 
management and the only way to write to another table is to instantiate 
a Connector and BatchWriter.

As such, it's very difficult, and possibly impossible with the current 
API, to write to a separate table inside of a Combiner without leaking 
resources inside of the TabletServer.

Definitely implement it in your ingest code :)

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