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 65452B739 for ; Sat, 31 Dec 2011 10:23:20 +0000 (UTC) Received: (qmail 89716 invoked by uid 500); 31 Dec 2011 10:23:17 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 89595 invoked by uid 500); 31 Dec 2011 10:22:57 -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 89587 invoked by uid 99); 31 Dec 2011 10:22:55 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 31 Dec 2011 10:22:55 +0000 X-ASF-Spam-Status: No, hits=0.7 required=5.0 tests=SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (athena.apache.org: local policy) Received: from [64.6.108.239] (HELO ponto.amerinoc.com) (64.6.108.239) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 31 Dec 2011 10:22:47 +0000 Received: from fbsd8.localdomain (205.83.broadband7.iol.cz [88.102.83.205]) (authenticated bits=128) by ponto.amerinoc.com (8.14.5/8.14.5) with ESMTP id pBVAMJqk071700 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 31 Dec 2011 11:22:24 +0100 (CET) (envelope-from hsn@sendmail.cz) Received: from [127.0.0.1] ([10.0.0.1]) by fbsd8.localdomain (8.14.4/8.14.4) with ESMTP id pBVAMC9r003702 for ; Sat, 31 Dec 2011 11:22:13 +0100 (CET) (envelope-from hsn@sendmail.cz) Message-ID: <4EFEE24C.9050102@sendmail.cz> Date: Sat, 31 Dec 2011 11:22:04 +0100 From: Radim Kolar User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:9.0) Gecko/20111222 Thunderbird/9.0.1 MIME-Version: 1.0 To: user@cassandra.apache.org Subject: Re: random keys and overlapping key ranges in SSTables References: <1325326134.49483.YahooMailNeo@web161202.mail.bf1.yahoo.com> In-Reply-To: <1325326134.49483.YahooMailNeo@web161202.mail.bf1.yahoo.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Antivirus: avast! (VPS 111231-0, 31.12.2011), Outbound message X-Antivirus-Status: Clean > Then for each read, Cassandra will go through all the SSTables (or > one SSTable in each level for the leveled compaction strategy)? How to deal with this > problem? bloom filters can guess right sstables to be read with high probability < 0.1%. In reality even if you are using size based compaction and have about 300 sstables, reading is fast unless there is row fragmentation and you are reading entire row.