Return-Path: Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: (qmail 66393 invoked from network); 3 Feb 2011 10:28:43 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 3 Feb 2011 10:28:43 -0000 Received: (qmail 57685 invoked by uid 500); 3 Feb 2011 10:28:41 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 57526 invoked by uid 500); 3 Feb 2011 10:28:39 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 57518 invoked by uid 99); 3 Feb 2011 10:28:39 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 03 Feb 2011 10:28:39 +0000 X-ASF-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (nike.apache.org: local policy) Received: from [209.85.214.172] (HELO mail-iw0-f172.google.com) (209.85.214.172) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 03 Feb 2011 10:28:30 +0000 Received: by iwc10 with SMTP id 10so997660iwc.31 for ; Thu, 03 Feb 2011 02:28:08 -0800 (PST) MIME-Version: 1.0 Received: by 10.231.205.205 with SMTP id fr13mr11214872ibb.120.1296728888790; Thu, 03 Feb 2011 02:28:08 -0800 (PST) Received: by 10.231.15.72 with HTTP; Thu, 3 Feb 2011 02:28:08 -0800 (PST) X-Originating-IP: [80.179.102.198] Date: Thu, 3 Feb 2011 12:28:08 +0200 Message-ID: Subject: Do supercolumns have a purpose? From: David Boxenhorn To: Cassandra Mailing List Content-Type: multipart/alternative; boundary=90e6ba4fc4b6c954f3049b5e38fa X-Virus-Checked: Checked by ClamAV on apache.org --90e6ba4fc4b6c954f3049b5e38fa Content-Type: text/plain; charset=ISO-8859-1 Is there any advantage to using supercolumns (columnFamilyName[superColumnName[columnName[val]]]) instead of regular columns with concatenated keys (columnFamilyName[superColumnName@columnName[val]])? When I designed my data model, I used supercolumns wherever I needed two levels of key depth - just because they were there, and I figured that they must be there for a reason. Now I see that in 0.7 secondary indexes don't work on supercolumns or subcolumns (is that right?), which seems to me like a very serious limitation of supercolumn families. It raises the question: Is there anything that supercolumn families are good for? And here's a related question: Why can't Cassandra implement supercolumn families as regular column families, internally, and give you that functionality? --90e6ba4fc4b6c954f3049b5e38fa Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Is there any advantage to using supercolumns (columnFamily= Name[superColumnName[columnName[val]]]) instead of regular columns with con= catenated keys (columnFamilyName[superColumnName@columnName[val]])?
When I designed my data model, I used supercolumns wherever I needed two le= vels of key depth - just because they were there, and I figured that they m= ust be there for a reason.

Now I see that in 0.7 secondary indexes d= on't work on supercolumns or subcolumns (is that right?), which seems t= o me like a very serious limitation of supercolumn families.

It raises the question: Is there anything that supercolumn families are= good for?

And here's a related question: Why can't Cassand= ra implement supercolumn families as regular column families, internally, a= nd give you that functionality?
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