Return-Path: Delivered-To: apmail-incubator-cassandra-user-archive@minotaur.apache.org Received: (qmail 12144 invoked from network); 5 Mar 2010 03:44:55 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 5 Mar 2010 03:44:55 -0000 Received: (qmail 29033 invoked by uid 500); 5 Mar 2010 03:44:43 -0000 Delivered-To: apmail-incubator-cassandra-user-archive@incubator.apache.org Received: (qmail 28851 invoked by uid 500); 5 Mar 2010 03:44:42 -0000 Mailing-List: contact cassandra-user-help@incubator.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: cassandra-user@incubator.apache.org Delivered-To: mailing list cassandra-user@incubator.apache.org Received: (qmail 28843 invoked by uid 99); 5 Mar 2010 03:44:42 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 05 Mar 2010 03:44:42 +0000 X-ASF-Spam-Status: No, hits=2.2 required=10.0 tests=FREEMAIL_FROM,HTML_MESSAGE,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of bill.w.au@gmail.com designates 209.85.160.175 as permitted sender) Received: from [209.85.160.175] (HELO mail-gy0-f175.google.com) (209.85.160.175) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 05 Mar 2010 03:44:40 +0000 Received: by gyd5 with SMTP id 5so1391762gyd.6 for ; Thu, 04 Mar 2010 19:44:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:message-id:subject :from:to:content-type; bh=4IC5GKFGUsNsAVIX9Vy7n7z9IH/MMEPRFdczWPpUBCo=; b=mapZFUGLwOCUMRirZ0/yW1jCW93mDzzgddb/uE/YkNYhEZ1KYwBC2wP/8y02KIHQ/I sRPYBoZMhyPiJTdAWJtqP9RH3Fr2ZTJQci7VdlEhBso4ll1udJhgMU9cDkOrSpGel9LG w4gOecPsROuCttu7pIkN2xOn9YPjjfQI4fHrw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=ub66A/UWnapKgdJRgRcl1qmfcCeFulVpSK9EhHjwRGoUyOoTAdH4G4e0L/WIq7Sol8 YhCieUyo2qZ9rOIrjWyJVQaPc0iklrdQsq2ZIO7q84ulKk/p1FbRk87WngpR3jOiPftJ xi2d7576NIzIutTruepnTOyNPNibL/9Isf2Xk= MIME-Version: 1.0 Received: by 10.150.209.11 with SMTP id h11mr495375ybg.300.1267760660082; Thu, 04 Mar 2010 19:44:20 -0800 (PST) Date: Thu, 4 Mar 2010 22:44:20 -0500 Message-ID: <3b5f72031003041944j2d12cb20wc5541a7464dcd7d5@mail.gmail.com> Subject: Memtable size and garbage collection in JVM From: Bill Au To: cassandra-user@incubator.apache.org Content-Type: multipart/alternative; boundary=000e0cd379eecdf07404810587a3 --000e0cd379eecdf07404810587a3 Content-Type: text/plain; charset=ISO-8859-1 I am running on a machine with 16 GB of memory. I am thinking that the bigger MemtableSizeIbMB, the more data will be kept in memory so there will be less disk I/O. Can I eliminate disk I/O all together if all my data fits inside Memtable? My application is constantly inserting new data and remove old ones. Will keeping everything in Memtable generate so much garbage collection activity that it would impact performance? Bill --000e0cd379eecdf07404810587a3 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable I am running on a machine with 16 GB of memory. =A0I am thinking that the b= igger MemtableSizeIbMB, the more data will be kept in memory so there will = be less disk I/O. =A0Can I eliminate disk I/O all together if all my data f= its inside Memtable? =A0My application is constantly inserting new data and= remove old ones. =A0Will keeping everything in Memtable generate so much g= arbage collection activity that it would impact performance?

Bill


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