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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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Josh Elser 2012-11-12, 14:44
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Re: ranges and iterators that transform results
Yes, we can definitely work around it as you suggest, though the
transformed key/value fit the semantics of the domain a bit better.  Since
we're using the intersecting iterator, I'm trying to hide the random
partition row id from a consumer of this API.
On Mon, Nov 12, 2012 at 9:44 AM, Josh Elser <[EMAIL PROTECTED]> wrote:

> 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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William Slacum 2012-11-13, 11:25
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB