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From: Stephen Pope <Stephen.Pope@quest.com>
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
CC: Asil Klin <asdkl93@gmail.com>
Subject: RE: Replacing supercolumns with composite columns; Getting the
 equivalent of retrieving a list of supercolumns by name
Thread-Topic: Replacing supercolumns with composite columns; Getting the
 equivalent of retrieving a list of supercolumns by name
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Date: Tue, 3 Jan 2012 22:31:42 +0000
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 The bonus you're talking about here, how do I apply that?

 For example, my columns are in the form of number.id such as 4.steve, 4.gr=
eg, 5.steve, 5.george. Is there a way to query a slice of numbers with a li=
st of ids? As in, I want all the columns with numbers between 4 and 10 whic=
h have ids steve or greg.

 Cheers,
 Steve

-----Original Message-----
From: Jeremiah Jordan [mailto:jeremiah.jordan@morningstar.com]=20
Sent: Tuesday, January 03, 2012 3:12 PM
To: user@cassandra.apache.org
Cc: Asil Klin
Subject: Re: Replacing supercolumns with composite columns; Getting the equ=
ivalent of retrieving a list of supercolumns by name

The main issue with replacing super columns with composite columns right no=
w is that if you don't know all your sub-column names you can't select mult=
iple "super columns" worth of data in the same query without getting extra =
stuff.  You have to use a slice to get all subcolumns of a given super colu=
mn, and you can't have disjoint slices, so if you want two super columns fu=
ll, you have to get all the other stuff that is in between them, or make tw=
o queries.
If you know what all of the sub-column names are you can ask for all of the=
 super/sub column pairs for all of the super columns you want and not get e=
xtra data.

If you don't need to pull multiple super columns at a time with slices like=
 that, then there isn't really an issue.

A bonus of using composite keys like this, is that if there is a specific s=
ub column you want from multiple super columns, you can pull all those out =
with a single multiget and you don't have to pull the rest of the columns..=
.

So there are pros and cons...

-Jeremiah


On 01/03/2012 01:58 PM, Asil Klin wrote:
> I have a super columns family which I always use to retrieve a list of=20
> supercolumns(with all subcolumns) by name. I am looking forward to=20
> replace all SuperColumns in my schema with the composite columns.
>
> How could I design schema so that I could do the equivalent of=20
> retrieving a list of supercolumns by name, in case of using composite=20
> columns.
>
> (As of now I thought of using the supercolumn name as the first=20
> component of the composite name and the subcolumn name as 2nd=20
> component of composite name.)