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Accumulo, mail # user - ranges and iterators that transform results


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Anthony Fox 2012-11-12, 13:51
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Re: ranges and iterators that transform results
Josh Elser 2012-11-12, 14:44
The last time I looked at that code, every resulting key was silently
removed by the TabletServerBatchReader(Iterator).

That being said, it was previously impossible to turn off that final range
check as you asked. I'd have to double check the code again, though.

Would it be possible in your application to place your aggregated
information in some serialized representation inside of the Value and
preserve the original Key?

On Monday, November 12, 2012, Anthony Fox <[EMAIL PROTECTED]> wrote:
> I am trying to limit scans to a subset of stored rows by setting ranges.
 The scan has an iterator that does some aggregation and transformation of
the result.  Specifically, it changes the rowid to be more meaningful but
at the same time outside of the specified range.  By instrumenting the
iterator with debug messages, I can verify that the expected rows are
actually processed.  But it appears that the range filter is applied to the
result of the transformation that the iterator is making.  Basically, I'm
trying to get something like a sql projection:
> select myTransformation(id) from myTable where id between (start and end);
> Is it possible to set the precedence of the range filter and the iterator
that I am using so that I can do this transformation without filtering all
the results?
>
> Thanks,
> Anthony
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Anthony Fox 2012-11-12, 15:29
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William Slacum 2012-11-13, 11:25