Return-Path: X-Original-To: apmail-hbase-user-archive@www.apache.org Delivered-To: apmail-hbase-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 548CAD14C for ; Wed, 3 Oct 2012 05:50:27 +0000 (UTC) Received: (qmail 58173 invoked by uid 500); 3 Oct 2012 05:50:25 -0000 Delivered-To: apmail-hbase-user-archive@hbase.apache.org Received: (qmail 57991 invoked by uid 500); 3 Oct 2012 05:50:25 -0000 Mailing-List: contact user-help@hbase.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@hbase.apache.org Delivered-To: mailing list user@hbase.apache.org Received: (qmail 57966 invoked by uid 99); 3 Oct 2012 05:50:24 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 03 Oct 2012 05:50:24 +0000 X-ASF-Spam-Status: No, hits=-0.0 required=5.0 tests=SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of anoopsj@huawei.com designates 119.145.14.65 as permitted sender) Received: from [119.145.14.65] (HELO szxga02-in.huawei.com) (119.145.14.65) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 03 Oct 2012 05:50:18 +0000 Received: from 172.24.2.119 (EHLO szxeml205-edg.china.huawei.com) ([172.24.2.119]) by szxrg02-dlp.huawei.com (MOS 4.3.4-GA FastPath queued) with ESMTP id APZ74317; Wed, 03 Oct 2012 13:49:55 +0800 (CST) Received: from SZXEML429-HUB.china.huawei.com (10.72.61.37) by szxeml205-edg.china.huawei.com (172.24.2.58) with Microsoft SMTP Server (TLS) id 14.1.323.3; Wed, 3 Oct 2012 13:47:57 +0800 Received: from SZXEML531-MBX.china.huawei.com ([fe80::61a8:2cb5:62f9:d4a4]) by SZXEML429-HUB.china.huawei.com ([10.72.61.37]) with mapi id 14.01.0323.003; Wed, 3 Oct 2012 13:47:56 +0800 From: Anoop Sam John To: "user@hbase.apache.org" Subject: RE: Column Qualifier space requirements Thread-Topic: Column Qualifier space requirements Thread-Index: AQHNn9vCc8FNb0wkDUOEeA1oOq0XspekMTYAgAA7QgCAAqeQnA== Date: Wed, 3 Oct 2012 05:47:56 +0000 Message-ID: <0CE69E9126D0344088798A3B7F7F80863A4DDD75@szxeml531-mbx.china.huawei.com> References: , In-Reply-To: Accept-Language: en-US, zh-CN Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.18.96.95] Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-CFilter-Loop: Reflected X-Virus-Checked: Checked by ClamAV on apache.org >It means that in order to save space I need to use smallest Column Qualifier (and sometimes it makes sense)... Yes=20 >However, why Column Family (byte array) is repeated for each KeyValue? Is it physically repeated for each cell? Yes CF byte[] also physically stored in every cell (every KV).. At the sto= rage level HBase deals with KVs and every KV is having a full identity of i= ts.[rowkey+cf+qualifier+timestamp] If you are working with 0.94 versions there is one optimization done wrt sp= ace saving. This is known as block level encoding. See the interface DataBl= ockEncoder and diff implementations available for it... -Anoop- ________________________________________ From: Fuad Efendi [fuad@efendi.ca] Sent: Tuesday, October 02, 2012 2:40 AM To: user@hbase.apache.org Subject: Re: Column Qualifier space requirements Thanks; It means that in order to save space I need to use smallest Column Qualifier (and sometimes it makes sense)... However, why Column Family (byte array) is repeated for each KeyValue? Is it physically repeated for each cell? > >Hi there, take a look at the Hbase Refguide here... > >http://hbase.apache.org/book.html#regions.arch > >For this section... > >9.7.5.4. KeyValue > > > > > >>Hi, >> >>Is column qualifier physically stored in a Cell? Or pointer to it? Do we >>need to care about long size such as >>my_very_long_qualifier:1 >> >>(size of a value is small in comparison to size of qualifier=8A) >> >>thanks >> >> > >=