> Would you guys consider adding this option to a future release? All improvements are considered :) Please create a ticket on https://issues.apache.org/jira/browse/CASSANDRA and reference CASSANDRA-3073
> If you want I can try to create a patch myself and submit it to you? Sounds like a plan. Thanks ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 10/07/2012, at 1:47 AM, Joost van de Wijgerd wrote: > Hello Cassandra Devs, > > We are currently trying to optimize our Cassandra system with > different workloads. One of our workload is update heavy (very). > > Currently we are running with a patch that allows the Live Ratio to go > below 1.0 (lower bound set to 0.1 now) which gives us a > bit better performance in terms of flushes on this particular CF. We > then experienced unexpected memory issues which on further > inspection seems to be related to the SlabAllocator. What happens is > that we allocate a Region of 1MB every couple of seconds (the columns > we write in this CF contain serialized session data, can be 100K > each), so overwrites are actually done into another Region and these > regions are only freed (most of the time) when the Memtable is > flushed. We actually added some debug logs and to write about 300MB to > disk we created roughly 3000 regions. (3GB of data, some of them might > be collected before the flush but probably not much) > > It would really great if we could use the native allocator only for > this CF. Since the SlabAllocator gives us very good results on our > other > CFs. (we tried running on a patched version with the HeapAllocator set > but went OOM almost immediately) > > I have found this issue in which Jonathan mentions he is ok with > adding a configuration option: > > https://issues.apache.org/jira/browse/CASSANDRA-3073 > > Unfortunately it seems the issue was closed and nothing was implemented. > > Would you guys consider adding this option to a future release? > SlabAllocator should be the default but in the CF properties the > HeapAllocator > can be set. > > If you want I can try to create a patch myself and submit it to you? > > Kind Regards > > Joost > > -- > Joost van de Wijgerd > Visseringstraat 21B > 1051KH Amsterdam > +31624111401 > joost.van.de.wijgerd@Skype > http://www.linkedin.com/in/jwijgerd
