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 9A286E90D for ; Thu, 13 Dec 2012 15:37:03 +0000 (UTC) Received: (qmail 14947 invoked by uid 500); 13 Dec 2012 15:37:01 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 14696 invoked by uid 500); 13 Dec 2012 15:37:00 -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 14663 invoked by uid 99); 13 Dec 2012 15:36:59 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 13 Dec 2012 15:36:59 +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 edlinuxguru@gmail.com designates 209.85.210.172 as permitted sender) Received: from [209.85.210.172] (HELO mail-ia0-f172.google.com) (209.85.210.172) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 13 Dec 2012 15:36:53 +0000 Received: by mail-ia0-f172.google.com with SMTP id z13so2111411iaz.31 for ; Thu, 13 Dec 2012 07:36:32 -0800 (PST) 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=N4S6u7e9T2tB9nauY5IaUXi/kZKDG6Yr9C+RtXgKIpM=; b=EuPL2r2oLwkOSIRsOVBswFQEDTkKwehqXDqlycQairOMIuaWnPaZJzZZVhAe5d3Utx BBsrJt0ansHNj7Anwcsi+kl9Ue/F1wRNcXMBAhk8NSzY6MeXAm95wxmXAPMWwshaCvxD t7wO9JBWjwRWD62yhKBG4XSsVOuxVUBN2XycWewHntjywdhzcHYma9OwSafHg71M97Cp quBgWmbUoIJzjw2PIrSnblk7L3aNfL9Pf01aaUu5mu7lXexLOVb5u67thNFDu1DRG5qB HP/xYt6L7LaJFM4F5jSGesAjDi9SlKXk73kz2iAn8deleThs0WPeQZigiqmE/yKshQhy WK6A== MIME-Version: 1.0 Received: by 10.50.237.103 with SMTP id vb7mr2026340igc.29.1355412992635; Thu, 13 Dec 2012 07:36:32 -0800 (PST) Received: by 10.64.97.106 with HTTP; Thu, 13 Dec 2012 07:36:32 -0800 (PST) In-Reply-To: References: <81D05238-BD4C-46C4-AAAA-CD6A68CF7567@thelastpickle.com> Date: Thu, 13 Dec 2012 10:36:32 -0500 Message-ID: Subject: Re: Help on MMap of SSTables From: Edward Capriolo To: "user@cassandra.apache.org" Content-Type: multipart/alternative; boundary=14dae9341205f3338a04d0bdad35 X-Virus-Checked: Checked by ClamAV on apache.org --14dae9341205f3338a04d0bdad35 Content-Type: text/plain; charset=ISO-8859-1 This issue has to be looked from a micro and macro level. On the microlevel the "best" way is workload specific. On the macro level this mostly boils down to data and memory size. Companions are going to churn cache, this is unavoidable. Imho solid state makes the micro optimization meanless in the big picture. Not that we should not consider tweaking flags but just saying it is hard to believe anything like that is a game change. On Monday, December 10, 2012, Rob Coli wrote: > On Thu, Dec 6, 2012 at 7:36 PM, aaron morton wrote: >> So for memory mapped files, compaction can do a madvise SEQUENTIAL instead >> of current DONTNEED flag after detecting appropriate OS versions. Will this >> help? >> >> >> AFAIK Compaction does use memory mapped file access. > > The history : > > https://issues.apache.org/jira/browse/CASSANDRA-1470 > > =Rob > > -- > =Robert Coli > AIM>ALK - rcoli@palominodb.com > YAHOO - rcoli.palominob > SKYPE - rcoli_palominodb > --14dae9341205f3338a04d0bdad35 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable This issue has to be looked from a micro and macro level. On the microlevel= the "best" way is workload specific. On the macro level this mos= tly boils down to data and memory size.

Companions are going to chu= rn cache, this is unavoidable. Imho solid state makes the micro optimizatio= n meanless in the big picture. Not that we should not consider tweaking fla= gs but just saying it is hard to believe anything like that is a game chang= e.

On Monday, December 10, 2012, Rob Coli <rcoli@palominodb.com> wrote:
> On Thu, Dec 6, 2012= at 7:36 PM, aaron morton <aa= ron@thelastpickle.com> wrote:
>> So for memory mapped files, compaction can do a madvise SEQUENTIAL= instead
>> of current DONTNEED flag after detecting appropriate O= S versions. Will this
>> help?
>>
>>
>>= AFAIK Compaction does use memory mapped file access.
>
> The history :
>
> https://issues.apache.org/jira/browse/CASS= ANDRA-1470
>
> =3DRob
>
> --
> =3DRobert = Coli
> AIM&GTALK - rcoli@palomino= db.com
> YAHOO - rcoli.palominob
> SKYPE - rcoli_palominodb=
> --14dae9341205f3338a04d0bdad35--