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Date: Fri, 9 Mar 2012 14:48:00 -0500
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 <CAGUtCHo13mfvBZLOjuG2F3ix9sfZ6CdTq_js5bLuLpJ5Rg1X=A@mail.gmail.com>
Subject: Re: filter on value ranges
From: Keith Turner <keith@deenlo.com>
To: accumulo-user@incubator.apache.org
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The WholeRowIterator can filter rows, just override it and implement
the filter function.

Also new in 1.4 is org.apache.accumulo.core.iterators.user.RowFilter.
If provides similar functionality, but does not require reading the
entire row into memory.

Keith

On Fri, Mar 9, 2012 at 1:11 PM, Kini, Ameet M. <akini@mitre.org> wrote:
>
>
>
>
> Thanks for the comments.
>
>
>
> I=92m ok with rolling my own iterator/filter but not sure how to go about
> doing it (see next para), so it=92d be great to get pointers on it. =A0I=
=92d
> prefer keeping the schema to how it is today where each employee is
> represented by a row in the table with a properties cf containing name an=
d
> salary cq. Here=92s how it looks today
>
>
>
> rowID colfam=A0=A0=A0=A0 colqual=A0=A0=A0=A0=A0=A0=A0=A0 value
>
>
>
> abc=A0 properties name=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 john
>
> abc=A0 properties salary=A0=A0=A0=A0 =A0=A0=A0=A0 10000
>
> def=A0 properties name=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 alice
>
> def=A0 properties salary=A0=A0=A0=A0 =A0=A0=A0=A0 20000
>
>
>
> Part of my confusion lies in not knowing how to implement this range filt=
er
> class, because my query needs to get both the name as well as salary base=
d
> on a particular salary. What I would like to do is something like a Filte=
r
> equivalent to WholeRowIterator, say WholeRowFilter whose accept(Key k, Va=
lue
> v) was provided the entire row in the Value argument alongwith appropriat=
e
> encodeRow/decodeRow as in WholeRowIterator. If the accept method returns
> true, the whole row is returned to the client. Then I could extend this
> class by writing a MyRangeFilter which would look inside the row and make
> row level accept/reject decisions based on values of particular cq.
>
>
>
> Maybe this WholeRowFilter is already there in some form?
>
>
>
> -Ameet Kini
>
>
>
> From: Aaron Cordova [mailto:aaron@cordovas.org]
> Sent: Friday, March 09, 2012 9:20 AM
> To: accumulo-user@incubator.apache.org
> Subject: Re: filter on value ranges
>
>
>
> To answer your question, I would not use built-in iterators for this.
>
>
>
> But if you were determined, you could use what is known as 'document
> sharding' as opposed to 'term sharding' and use an intersecting iterator.
>
>
>
> Instructions on how to do this should be added to the manual ...
>
>
>
>
>
> On Mar 9, 2012, at 9:07 AM, Kini, Ameet M. wrote:
>
>
>
>
>
> In 1.4, is there a way to use built-in iterators to run the following que=
ry
> :
>
> =A0 =93get the name and salary of all employees where the salary is betwe=
en X
> and Y=94
>
>
>
> Assuming a straightforward schema where name and salary are both cq.
>
>
>
> I=92d like both the cq restriction and the range predicate applied on the
> tservers.
>
>
>
> I see that Scanner.setColumnQualifierRegex would take care of the cq
> restriction. But I don=92t know of a built-in iterator for the range pred=
icate
> and I don=92t know of how to compose those two iterators.
>
>
>
> Thanks,
>
> -Ameet Kini
>
>
>
>