Arena allocation is an improvement feature, 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 <tbarbu...@gmail.com> a écrit sur 02/07/2014 17:40:18 : > De : tommaso barbugli <tbarbu...@gmail.com> > A : user@cassandra.apache.org, > Date : 02/07/2014 17:40 > Objet : Re: keyspace with hundreds of columnfamilies > > 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.hardo...@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 <tbarbu...@gmail.com> a écrit sur 02/07/2014 10:13:41 : > > > De : tommaso barbugli <tbarbu...@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
