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 2B48710625 for ; Thu, 27 Nov 2014 17:56:41 +0000 (UTC) Received: (qmail 90318 invoked by uid 500); 27 Nov 2014 17:56:38 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 90277 invoked by uid 500); 27 Nov 2014 17:56:38 -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 90267 invoked by uid 99); 27 Nov 2014 17:56:38 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 27 Nov 2014 17:56:38 +0000 X-ASF-Spam-Status: No, hits=0.7 required=5.0 tests=RCVD_IN_DNSWL_NONE,SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (athena.apache.org: local policy) Received: from [81.169.146.180] (HELO mo4-p05-ob.smtp.rzone.de) (81.169.146.180) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 27 Nov 2014 17:56:32 +0000 X-RZG-AUTH: :PGMXYU2paOu7c9Xwco3dmZW0S+ljHg2rbesPz7csaJmhszrUTlNYSbirnZusWbr7Myc+ X-RZG-CLASS-ID: mo05 Received: from hh2-mail.hh.nde.ag (gw-hh2.hh.nde.ag [85.183.17.20]) by post.strato.de (RZmta 36.2 AUTH) with ESMTPA id y01782qARHs31uz for ; Thu, 27 Nov 2014 18:54:03 +0100 (CET) Received: from hh2-www (hh2-www.hh.nde.ag [192.168.102.4]) by hh2-mail.hh.nde.ag (Postfix) with ESMTP id 3802E1C059 for ; Thu, 27 Nov 2014 18:54:03 +0100 (CET) Received: from lskn-h1-http-gw.niedersachsen.de (lskn-h1-http-gw.niedersachsen.de [195.37.205.30]) by www3.nde.ag (Horde Framework) with HTTP; Thu, 27 Nov 2014 18:54:03 +0100 Date: Thu, 27 Nov 2014 18:54:03 +0100 Message-ID: <20141127185403.Horde.M9aZdKXun32Ific7HqC2ng9@www3.nde.ag> From: Jens-Uwe Mozdzen To: user@cassandra.apache.org Subject: Re: Column family ID mismatch-Error on concurrent schema modifications References: <20141127142534.Horde.4rUxar8x7aa5JS93x4sdxQ7@www3.nde.ag> In-Reply-To: User-Agent: Internet Messaging Program (IMP) H5 (6.2.2) Accept-Language: de,en Content-Type: text/plain; charset=UTF-8; format=flowed; DelSp=Yes MIME-Version: 1.0 Content-Disposition: inline X-Virus-Checked: Checked by ClamAV on apache.org Hi Eric, Zitat von Eric Stevens : > Be careful with creating many dynamically created column families unless > you're cleaning up old ones to keep the total number of CF's reasonable. > Having many column families will increase memory pressure and reduce > overall performance. will "inactive" CFs be released from C*'s memory after i.e. a few days or when under resource pressure? We do intend to have quite some hundreds of tables, but with only 10% actively used (no reads nor writes) after some time. These CFs are used as "time buckets", but are to be kept for speedy recovery. Of course, this design may be substituted by some external backup mechanism, but I'd like to keep that as "plan C" ;) Regards, Jens -- Jens-U. Mozdzen voice : +49-40-559 51 75 NDE Netzdesign und -entwicklung AG fax : +49-40-559 51 77 Postfach 61 03 15 mobile : +49-179-4 98 21 98 D-22423 Hamburg e-mail : jmozdzen@nde.ag Vorsitzende des Aufsichtsrates: Angelika Mozdzen Sitz und Registergericht: Hamburg, HRB 90934 Vorstand: Jens-U. Mozdzen USt-IdNr. DE 814 013 983