From user-return-9798-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Mon Oct 11 11:12:31 2010 Return-Path: Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: (qmail 44142 invoked from network); 11 Oct 2010 11:12:31 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 11 Oct 2010 11:12:31 -0000 Received: (qmail 73297 invoked by uid 500); 11 Oct 2010 11:12:29 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 73222 invoked by uid 500); 11 Oct 2010 11:12:25 -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 73214 invoked by uid 99); 11 Oct 2010 11:12:25 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 11 Oct 2010 11:12:25 +0000 X-ASF-Spam-Status: No, hits=2.2 required=10.0 tests=FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of arijit72@gmail.com designates 209.85.216.179 as permitted sender) Received: from [209.85.216.179] (HELO mail-qy0-f179.google.com) (209.85.216.179) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 11 Oct 2010 11:12:17 +0000 Received: by qyk36 with SMTP id 36so720391qyk.10 for ; Mon, 11 Oct 2010 04:11:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=kwY9juQRMZJ0Gzjqz0+TuVUC/vlEFumSGyDZUHbuGJQ=; b=pvVIeZF9H+cY0E6mKgR7jUR3YX0tz996V/xmvAzDyPbThONy8fgIQXhhfZ2nydIIRU tOQNQQl5ffL5Vx0SxRPhW09ZhAKM/rsLI/3IDUc2JxxE8J4hZmWUNC0zaQh25RX6tBX9 JgtA1sr31LBMIT0OPPDOAHfdUowBTYwODJwTE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=qVgvem583l8wXvS4wUBUt5Rw9CkKRrXZWBjOKbA0mUfHstbkkwgh58BpMVa2qoKE13 D7K9OdXXuxbeAEq2tgEkF6edLL7WJl/e3c8XScGVkikE0HUs/Zxdumexg7rwYw1lJs9P +923/SjjkBznesF4uzDA5RI/dBhbax7/ZqOTU= MIME-Version: 1.0 Received: by 10.229.211.7 with SMTP id gm7mr5019101qcb.72.1286795516181; Mon, 11 Oct 2010 04:11:56 -0700 (PDT) Received: by 10.229.182.209 with HTTP; Mon, 11 Oct 2010 04:11:56 -0700 (PDT) In-Reply-To: References: Date: Mon, 11 Oct 2010 16:41:56 +0530 Message-ID: Subject: Re: Cassandra newbie question From: Arijit Mukherjee To: user@cassandra.apache.org Content-Type: text/plain; charset=ISO-8859-1 X-Virus-Checked: Checked by ClamAV on apache.org Just a follow on question to this - would PIG be a good fit for such questions? Arijit On 11 October 2010 14:31, Arijit Mukherjee wrote: > Hi All > > I've just started reading about Cassandra and writing simple tests > using Cassandra 0.6.5 to see if we can use it for our product. > > I have a data store with a set of columns, like C1, C2, C3, and C4, > but the columns aren't mandatory. For example, there can be a list of > (k.v) pairs with only C1 and C2, but no C3 and C4. At the same time, > there can be a set of records with all the columns present. It's > possible to consider them as three sets A (with all columns), B (with > C1 and C2) and C (with C3 and C4). And I'm trying to find out the > following: > > 1. A - B (all records who don't have C3 and C4) and A - C (all record > who don't have C1 and C2) > 2. records for whom C2 != C4 > > It's possible to pick all records and do this processing in my client > code - but that won't perform well. Is there any way to do these > within Cassandra? For example, by passing a list of column names so > that cassandra returns the records with only those columns? > > Regards > Arijit > -- "And when the night is cloudy, There is still a light that shines on me, Shine on until tomorrow, let it be."