Return-Path: X-Original-To: apmail-cassandra-user-archive@www.apache.org Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 1027C4AD0 for ; Tue, 31 May 2011 21:22:29 +0000 (UTC) Received: (qmail 25882 invoked by uid 500); 31 May 2011 21:22:27 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 25836 invoked by uid 500); 31 May 2011 21:22:26 -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 25828 invoked by uid 99); 31 May 2011 21:22:26 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 31 May 2011 21:22:26 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_LOW,RFC_ABUSE_POST,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of edlinuxguru@gmail.com designates 209.85.214.172 as permitted sender) Received: from [209.85.214.172] (HELO mail-iw0-f172.google.com) (209.85.214.172) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 31 May 2011 21:22:22 +0000 Received: by iwn39 with SMTP id 39so6473654iwn.31 for ; Tue, 31 May 2011 14:22:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type; bh=KsJovXnQ6mh84jAX/SHJ9xWfA1DVvT1fzZtZ/3RoJ/Q=; b=QSZQrvpzWataAMncF9iIgD4Phw6VxQmAtOzEjAGepBY/v1kE0MSvY9SlowCWRTOGVI lhmfV65ChVgJfRD+D7NKIIyXs5QsgmmCDa/JL+iPxjzHGQeQm1EZNU9HsRcqq0uS3PuP tfonQZ/UFt/I7gcXf9Xzt6R7HeEMb3bZx10r8= 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=wrNh+KZJm828afA7XI5NhCuzRi+nnQ2q9XXRrV3FutitdPL/Dth1Evafs68+gixhMq Jlxn2674dOWn+gW67LIkrHLXa+YO/g88N3d74UkuNDcMfUMyxm+w0aLxfdDPbnTP30EQ ml7I31quzIg4u+uXJNlKFqIh0KjyX7gN63rLc= MIME-Version: 1.0 Received: by 10.42.28.200 with SMTP id o8mr10309271icc.312.1306876920270; Tue, 31 May 2011 14:22:00 -0700 (PDT) Received: by 10.42.19.3 with HTTP; Tue, 31 May 2011 14:22:00 -0700 (PDT) In-Reply-To: References: Date: Tue, 31 May 2011 17:22:00 -0400 Message-ID: Subject: Re: Appending to fields From: Edward Capriolo To: user@cassandra.apache.org Content-Type: multipart/alternative; boundary=20cf3042722299115e04a498fe6f --20cf3042722299115e04a498fe6f Content-Type: text/plain; charset=ISO-8859-1 On Tue, May 31, 2011 at 5:03 PM, Dan Kuebrich wrote: > > > On Tue, May 31, 2011 at 4:57 PM, Victor Kabdebon < > victor.kabdebon@gmail.com> wrote: > >> As Jonathan stated I believe that the insert is in O(N + M), unless there >> are some operations that I don't know. >> >> There are other NoSQL database that can be used with Cassandra as >> "buffers" for quick access and modification and then after the content can >> be dumped into Cassandra for long term storage. Here is an example with >> Redis : >> >> http://redis.io/commands/append >> The "append" command is said to be in O(1) but it is a little bit >> suspicious to me... >> >> Best regards, >> Victor Kabdebon >> http://www.voxnucleus.fr >> > > I think perhaps OP meant O(N * M), where N is number of rows and M is total > bytes. > > Either way, won't cassandra be effectively buffering appends in memtable > (well, also appending to commit log) until flush occurs to sstable? > I never learned log 0 notation. However since a write is "fast" and cassandra "reads" are slow considering them equal for a computational analysis is heading down the wrong path. Cassandra "appends" are normally done by using a new TimeUUID as the column name and supplying the value in the value. The read half of the process reads with a column slice rather then reading a single column and joins the data client side. What you are doing is append by inserting N columns, then reconcile on the read side. --20cf3042722299115e04a498fe6f Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

On Tue, May 31, 2011 at 5:03 PM, Dan Kue= brich <dan.k= uebrich@gmail.com> wrote:


On Tue, May 31, 2011 at 4:57 PM, Vi= ctor Kabdebon <victor.kabdebon@gmail.com> wrote:
=
As Jonathan stated I believe that the insert is in O(N + M), unless th= ere are some operations that I don't know.

The= re are other NoSQL database that =A0can be used with Cassandra as "buf= fers" for quick access and modification and then after the content can= be dumped into Cassandra for long term storage. Here is an example with Re= dis :

The "append"= command is said to be in O(1) but it is a little bit suspicious to me...

Best regards,
Victor Kabdebon
<= div>http://www.voxnu= cleus.fr

I think perhaps O= P meant O(N * M), where N is number of rows and M is total bytes.

Either way, won't cassandra be effectively buffering app= ends in memtable (well, also appending to commit log) until flush occurs to= sstable?

I never learned log 0 notation. However since a writ= e is "fast" and cassandra "reads" are slow considering = them equal for a computational analysis is heading down the wrong path. Cas= sandra "appends" are normally done by using a new TimeUUID as the= column name and supplying the value in the value. The read half of the pro= cess reads with a column slice rather then reading a single column and join= s the data client side. What you are doing is append by inserting N columns= , then reconcile on the read side.
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