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 74AFC11C97 for ; Wed, 2 Jul 2014 16:36:24 +0000 (UTC) Received: (qmail 80344 invoked by uid 500); 2 Jul 2014 16:36:22 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 80311 invoked by uid 500); 2 Jul 2014 16:36:21 -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 80301 invoked by uid 99); 2 Jul 2014 16:36:21 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 02 Jul 2014 16:36:21 +0000 X-ASF-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_MESSAGE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [91.209.25.138] (HELO cer69mx21.cirtil.fr) (91.209.25.138) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 02 Jul 2014 16:36:18 +0000 X-PJ: In-Reply-To: References: To: user@cassandra.apache.org MIME-Version: 1.0 Subject: Re: keyspace with hundreds of columnfamilies X-KeepSent: 16650AFD:280CBB9F-C1257D09:005B1087; type=4; name=$KeepSent From: Romain HARDOUIN Message-ID: Date: Wed, 2 Jul 2014 18:35:51 +0200 Content-Type: multipart/alternative; boundary="=_alternative 005B2E2BC1257D09_=" X-Virus-Checked: Checked by ClamAV on apache.org Message en plusieurs parties au format MIME --=_alternative 005B2E2BC1257D09_= Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Arena allocation is an improvement feature, not a limitation.=20 It was introduced in Cassandra 1.0 in order to lower memory fragmentation=20 (and therefore promotion failure). AFAIK It's not intended to be tweaked so it might not be a good idea to=20 change it. Best, Romain tommaso barbugli a =E9crit sur 02/07/2014 17:40:18 : > De : tommaso barbugli > A : user@cassandra.apache.org,=20 > Date : 02/07/2014 17:40 > Objet : Re: keyspace with hundreds of columnfamilies >=20 > 1MB per column family sounds pretty bad to me; is this something I=20 > can tweak/workaround somehow? >=20 > Thanks > Tommaso >=20 > 2014-07-02 17:21 GMT+02:00 Romain HARDOUIN : > The trap is that each CF will consume 1 MB of memory due to arena=20 allocation.=20 > This might seem harmless but if you plan thousands of CF it means=20 > thousands of mega bytes...=20 > Up to 1,000 CF I think it could be doable, but not 10,000.=20 >=20 > Best,=20 >=20 > Romain=20 >=20 >=20 > tommaso barbugli a =E9crit sur 02/07/2014 10:13:41 : >=20 > > De : tommaso barbugli =20 > > A : user@cassandra.apache.org,=20 > > Date : 02/07/2014 10:14=20 > > Objet : keyspace with hundreds of columnfamilies=20 > >=20 > > Hi,=20 > > Are there any known issues, shortcomings about organising data in=20 > > hundreds of column families?=20 > > At this present I am running with 300 column families but I expect=20 > > that to get to a couple of thousands.=20 > > Is this something discouraged / unsupported (I am using Cassandra=20 2.0).=20 > >=20 > > Thanks=20 > > Tommaso --=_alternative 005B2E2BC1257D09_= Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Arena allocation is an improvement featu= re, not a limitation.
It was introduced in Cassandra 1.0 in order to lower memory fragmentation (and therefore promotion failure).
AFAIK It's not intended to be tweaked so it might not be a good idea to change it.

Best,
Romain

tommaso barbugli <tbarbugli@gmail.com> a =E9cr= it sur 02/07/2014 17:40:18 :

> De : tommaso barbugli <tbarbugli@gmail.com>
> A : user@cassandra.apache.org,
> Date : 02/07/2014 17:40
> Objet : Re: keyspace with hundreds of columnfam= ilies
>
> 1MB per column family sounds pretty bad to me; is this something I
> can tweak/workaround somehow?
>
> Thanks
> Tommaso
>

> 2014-07-02 17:21 GMT+02:00 Romain HARDOUIN <= romain.hardouin@urssaf.fr>:
> The trap is that each CF will consume 1 MB of memory due to arena allocation.
> This might seem harmless but if you plan thousands of CF it means
> thousands of mega bytes...
> Up to 1,000 CF I think it could be doable, but not 10,000.
>
> Best,
>
> Romain
>
>
> tommaso barbugli <tbarbugli@gmail.com> a =E9crit sur 02/07/2014 10:13:41 :
>
> > De : tommaso barbugli <tbarbugli@gmail.com>
> > A : user@cassandra.apache.org,
> > Date : 02/07/2014 10:14
> > Objet : keyspace with hundreds of columnfamilies
> >
> > Hi,
> > Are there any known issues, shortcomings about organising data in
> > hundreds of column families?
> > At this present I am running with 300 column families but I expect
> > that to get to a couple of thousands.
> > Is this something discouraged / unsupported (I am using Cassandra 2.0).
> >
> > Thanks
> > Tommaso --=_alternative 005B2E2BC1257D09_=--