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 4F26A9B48 for ; Wed, 2 May 2012 19:27:03 +0000 (UTC) Received: (qmail 93903 invoked by uid 500); 2 May 2012 19:27:01 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 93876 invoked by uid 500); 2 May 2012 19:27:01 -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 93868 invoked by uid 99); 2 May 2012 19:27:01 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 02 May 2012 19:27:01 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of skrolle@gmail.com designates 209.85.213.44 as permitted sender) Received: from [209.85.213.44] (HELO mail-yw0-f44.google.com) (209.85.213.44) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 02 May 2012 19:26:54 +0000 Received: by yhq56 with SMTP id 56so1271302yhq.31 for ; Wed, 02 May 2012 12:26:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=F8Vdl2xbrSyIClUPKrysvYVgzkobF2PP4rhnUXvXwfY=; b=Z9ocbfNg2sjC0BShGbvdPfrmd+Rywy7MOA/MEFhPycM8qj4HkR2O1A0cSfTAtkiLzq 2eb8aT+e9B7VUwN4WWja868A3kOwxADC+vbBdqVvVyShYLRzuQHMD1JELksvUV0NUo5V jXOp5474JVys9nl5Yg+gph7HgY0xFzoouwOF9DO0mh9ef9aJ8vkVqe7M8RAN01tHaFwW CDIdcCKqbtPni9/WBq3zP88mIngvq15LMB4a8jqtvAkjNR02Sh7jYanLa1ItSp2zHE20 Qwd1q2/QVOLBKQl7lTQ2sqif/pqRb+8VcVuqTxR+//Ik4UXFx0rV3i9l6412aFMprdU+ J+dg== MIME-Version: 1.0 Received: by 10.236.114.169 with SMTP id c29mr32471857yhh.37.1335986793540; Wed, 02 May 2012 12:26:33 -0700 (PDT) Received: by 10.101.184.30 with HTTP; Wed, 2 May 2012 12:26:33 -0700 (PDT) In-Reply-To: References: <4F98FE29.70007@sitevision.se> <4F99173E.9080801@sitevision.se> <7DDDB474-E321-43AB-8BBC-C0EF0C34A916@thelastpickle.com> Date: Wed, 2 May 2012 21:26:33 +0200 Message-ID: Subject: Re: Question regarding major compaction. From: =?ISO-8859-1?Q?Henrik_Schr=F6der?= To: user@cassandra.apache.org Content-Type: multipart/alternative; boundary=bcaec543146440eaa404bf12aac4 --bcaec543146440eaa404bf12aac4 Content-Type: text/plain; charset=ISO-8859-1 On Tue, May 1, 2012 at 10:00 PM, Oleg Proudnikov wrote: > There is this note regarding major compaction in the tuning guide: > > "once you run a major compaction, automatic minor compactions are no longer > triggered frequently forcing you to manually run major compactions on a > routine > basis" > > I think, this means that unless you run major compactions regularly, the > number > of sstables will naturally grow leading to incremental degradation in read > performance for update workloads. No, that's not true. Minor automatic compactions continue in the exact same way as before, and if you outgrow that single largest file your major compaction resulted in, you'll be in exactly the same state as if you had never done that major compaction at all. /Henrik --bcaec543146440eaa404bf12aac4 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Tue, May 1, 2012 at 10:00 PM, Oleg Proudnikov <olegp@cloudorange.co= m> wrote:
There is this note regarding major compaction in the tuning guide:

"once you run a major compaction, automatic minor compactions are no l= onger
triggered frequently forcing you to manually run major compactions on a rou= tine
basis"

I think, this means that unless you run major compactions regularly, the nu= mber
of sstables will naturally grow leading to incremental degradation in read<= br> performance for update workloads.

No, that's not t= rue. Minor automatic compactions continue in the exact same way as before, = and if you outgrow that single largest file your major compaction resulted = in, you'll be in exactly the same state as if you had never done that m= ajor compaction at all.


/Henrik
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