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From david lee <iecan...@gmail.com>
Subject Re: "range query" vs "slice range query"
Date Thu, 26 May 2011 02:29:09 GMT
so, that was actually simpler than i thought ay?
cheers guys~

On 26 May 2011 05:38, Roland Gude <roland.gude@yoochoose.com> wrote:

> That is correct. Random partitioner orders rows according to the MD5 sum.
>
> Am 25.05.2011 um 16:11 schrieb "Robert Jackson" <robertj@promedicalinc.com
> >:
>
> Also, it is my understanding that if you are not using
> OrderPreservingPartitioner a get_range_slices may not return what you would
> expect.
>
> With the RandomPartitioner you can iterate over the complete list by using
> the last row key as the start for subsequent requests, but if you are using
> a single query you will be returned all the rows where the returned row
> key's md5 is between the md5 of the start row key and stop row key.
>
> Reference:
> http://wiki.apache.org/cassandra/FAQ - "Why aren't range slices/sequential
> scans giving me the expected results?"
>
> Robert Jackson
>
> ------------------------------
> *From: *"Jonathan Ellis" <jbellis@gmail.com>
> *To: *user@cassandra.apache.org
> *Sent: *Wednesday, May 25, 2011 8:54:34 AM
> *Subject: *Re: "range query" vs "slice range query"
>
> get_range_slices is the api to get a slice (of columns) from each of a
> range (of rows)
>
> On Wed, May 25, 2011 at 3:42 AM, david lee <iecanfly@gmail.com> wrote:
> > hi guys,
> > i'm reading up on the book "Cassandra - Definitive guide"
> > and i don't seem to understand what it says about "ranges and slices"
> > my understanding is
> > a range as in "a mathematical range to define a subset from an ordered
> set
> > of elements",
> > in cassandra typically means a range of rows whereas
> > a slice means a range of columns.
> > a range query refers to a query to retrieve a range of rows whereas
> > a slice range queyr refers to a query to retrieve range of columns within
> a
> > row.
> > i may be talking about total nonsense but i really am more confused after
> > reading this portion of the book
> >
> http://books.google.com/books?id=MKGSbCbEdg0C&pg=PA134&lpg=PA134&dq=cassandra+%22range+query%22+%22range+slice%22&source=bl&ots=XoPB4uA60u&sig=uDDoQe0FRkQobHnr-vPvvQ3B8TQ&hl=en&ei=ub3cTcvGLZLevQOuxs3CDw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CCwQ6AEwAw#v=onepage&q=cassandra%20%22range%20query%22%20%22range%20slice%22&f=false
> > many thanx in advance
> > david
> >
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com
>
>

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