Hi, thank you for you replies on this; regarding the arena memory is this a fixed memory allocation or is some sort of in memory caching? I ask because I think that a substantial portion of the column families created will not be queried that frequently (and some will become inactive and stay like that really long time)
Thank you, Tommaso 2014-07-02 18:35 GMT+02:00 Romain HARDOUIN <romain.hardo...@urssaf.fr>: > 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 >
