From user-return-17361-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Sun Jun 5 19:29:27 2011 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 12A9764ED for ; Sun, 5 Jun 2011 19:29:27 +0000 (UTC) Received: (qmail 69518 invoked by uid 500); 5 Jun 2011 19:29:25 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 69485 invoked by uid 500); 5 Jun 2011 19:29:25 -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 69477 invoked by uid 99); 5 Jun 2011 19:29:25 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 05 Jun 2011 19:29:25 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,RFC_ABUSE_POST,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of nguyen.h.khanh@gmail.com designates 209.85.216.172 as permitted sender) Received: from [209.85.216.172] (HELO mail-qy0-f172.google.com) (209.85.216.172) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 05 Jun 2011 19:29:17 +0000 Received: by qyk29 with SMTP id 29so743238qyk.10 for ; Sun, 05 Jun 2011 12:28:56 -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=b23c6GL0POg60ltFHPEPFuriR4Qvg3diSTw5NsjlITk=; b=rXbDfDREuRh/25dGX4xVN9MzILWoUv6z5EZA27IgJQYM6tzBcXRdXyadUllihbvHrL 8Hw3ngyAopKuFvqO1KpwyYIqAlApY40ywOnTsmOHLzihCz6mLqBroTvR1Dy+OWQyvdiU bXetTcVgfad0JqVwBmgIaya9Z1ftm832up+7g= 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=V904pCC1dP8KJkmJFvBy2SDkvpJl7HuTMaaxukjVDQmIl0k4uBk/TH5ZoHhdR/Oa9K jla+91UFMBYNQL7OPrD8JKu2sY/U32F9eYc3RT4DzdFskOWNrSt6Uo8/aSu/3ZY2VA34 pMFosYq147IoOBsV/If9hsK+xDZqCIqqKnSig= MIME-Version: 1.0 Received: by 10.224.214.137 with SMTP id ha9mr1351635qab.290.1307302136676; Sun, 05 Jun 2011 12:28:56 -0700 (PDT) Received: by 10.224.80.147 with HTTP; Sun, 5 Jun 2011 12:28:56 -0700 (PDT) In-Reply-To: <1307297826627-6442802.post@n2.nabble.com> References: <1307297826627-6442802.post@n2.nabble.com> Date: Sun, 5 Jun 2011 15:28:56 -0400 Message-ID: Subject: Re: Direct control over where data is stored? From: Khanh Nguyen To: user@cassandra.apache.org Content-Type: text/plain; charset=ISO-8859-1 X-Virus-Checked: Checked by ClamAV on apache.org On Sun, Jun 5, 2011 at 2:17 PM, mcasandra wrote: > Please give more detailed info about what exactly you are worried about or > trying to solve. In general, we are trying to devise a partitioning and replication scheme that takes into account social relations between data. > Please take a step back and look at cassandra's architecture again and what > it's trying to solve. It's a distributed database so if you do what you are > describing there is a potential of getting hotspots. Which will probably > lead in other problems. You might solve one problem but then intriduce > another like slow reads or one node getting overloaded. Exactly, we understand that this is an issue. In fact, one reason we're working on this project is to see how well our proposed partitioning and replication scheme distribute the load while preserving social locality. > I also suggest run some stress test and worry about the load, performance > only if it is a real problem for your kind of data. Is there a way to tell where a piece of data is stored in a cluster? For example, can I tell if LastNameColumn['A'] is stored at node 1 in the ring? Thanks. -k