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 B62517643 for ; Sun, 25 Dec 2011 19:58:50 +0000 (UTC) Received: (qmail 60240 invoked by uid 500); 25 Dec 2011 19:58:48 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 60220 invoked by uid 500); 25 Dec 2011 19:58:48 -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 60179 invoked by uid 99); 25 Dec 2011 19:58:48 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 25 Dec 2011 19:58:48 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of scode@scode.org designates 74.125.82.44 as permitted sender) Received: from [74.125.82.44] (HELO mail-ww0-f44.google.com) (74.125.82.44) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 25 Dec 2011 19:58:40 +0000 Received: by wgbdr13 with SMTP id dr13so15573786wgb.25 for ; Sun, 25 Dec 2011 11:58:19 -0800 (PST) MIME-Version: 1.0 Received: by 10.227.203.131 with SMTP id fi3mr26991496wbb.17.1324843099455; Sun, 25 Dec 2011 11:58:19 -0800 (PST) Sender: scode@scode.org Received: by 10.180.99.34 with HTTP; Sun, 25 Dec 2011 11:58:19 -0800 (PST) X-Originating-IP: [71.202.44.53] In-Reply-To: <4EF72184.2050201@sendmail.cz> References: <4EF72184.2050201@sendmail.cz> Date: Sun, 25 Dec 2011 11:58:19 -0800 X-Google-Sender-Auth: oMNwZempOd7mIhQU5UUkwCkaH4o Message-ID: Subject: Re: reported bloom filter FP ratio From: Peter Schuller To: user@cassandra.apache.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Virus-Checked: Checked by ClamAV on apache.org > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0Read Count: 68844 [snip] > why reported bloom filter FP ratio is not counted like this >>>> 10/68844.0 > 0.00014525594096798558 Because the read count is total amount of reads to the CF, while the bloom filter is per sstable. The number of individual reads to sstables will be higher than the number of reads to the CF (unless you happen to have exactly one sstable or no rows ever span sstables). --=20 / Peter Schuller (@scode, http://worldmodscode.wordpress.com)