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From Russ Weeks <rwe...@newbrightidea.com>
Subject Re: Distinguishing between processed and unprocessed data in an Iterator
Date Wed, 01 Oct 2014 02:13:39 GMT
I see, thanks Christopher.

For a lot of the iterators that my colleagues and I are thinking about,
we'd be OK with constraints like, "only apply this iterator at scan time"
and "don't stick other iterators on top of this one". But my understanding
is that Accumulo itself, either on the tserver-side and/or the
scanner-side, might arbitrarily re-seek any type of iterator at any time it
chooses.

-Russ

On Tue, Sep 30, 2014 at 6:41 PM, Christopher <ctubbsii@apache.org> wrote:

> On Tue, Sep 30, 2014 at 9:34 PM, Russ Weeks <rweeks@newbrightidea.com>
> wrote:
>
>> > an iterator in the scan scope would be guaranteed to only see
>> unprocessed data if the iterator has not been configured for minor
>> compaction or major compaction scopes at all
>>
>> Excellent, thanks Christopher. That simplifies things. One more question:
>> I understand that an iterator may be re-seeked at any point in its
>> lifetime, which could cause it to see unprocessed data a second time. I
>> assume this is true for scan-scope iterators as well?
>>
>> -Russ
>>
>>
> Yes, it is true for scan scope also. A simple example would be another
> user iterator that sits on top of yours that does a Cartesian product of
> its data source.
>
> --
> Christopher L Tubbs II
> http://gravatar.com/ctubbsii
>
>

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