You can experiment quite easily without even needing to restart the Cassandra service.
The caches (row and key) can be enabled on a table-by-table basis via a schema directive. But the cache capacity (which is the one that you referred to in your original post, set to 0 in cassandra.yaml) is a global setting and can be manipulated via JMX or nodetool (nodetool setcachecapacity <https://docs.datastax.com/en/cassandra/2.1/cassandra/tools/toolsSetCacheCapacity.html> ). Arvydas On Sun, Mar 12, 2017 at 9:46 AM, preetika tyagi <preetikaty...@gmail.com> wrote: > Thanks, Matija! That was insightful. > > I don't really have a use case in particular, however, what I'm trying to > do is to figure out how the Cassandra performance can be leveraged by using > different caching mechanisms, such as row cache, key cache, partition > summary etc. Of course, it will also heavily depend on the type of workload > but I'm trying to gain more understanding of what's available in the > Cassandra framework. > > Also, I read somewhere that either row cache or key cache can be turned on > for a specific table, not both. Based on your comment, I guess the > combination of page cache and key cache is used widely for tuning the > performance. > > Thanks, > Preetika > > On Sat, Mar 11, 2017 at 2:01 PM, Matija Gobec <matija0...@gmail.com> > wrote: > >> Hi, >> >> In 99% of use cases Cassandra's row cache is not something you should >> look into. Leveraging page cache yields good results and if accounted for >> can provide you with performance increase on read side. >> I'm not a fan of a default row cache implementation and its invalidation >> mechanism on updates so you really need to be careful when and how you use >> it. There isn't much to configuration as there is to your use case. Maybe >> explain what are you trying to solve with row cache and people can get into >> discussion with more context. >> >> Regards, >> Matija >> >> On Sat, Mar 11, 2017 at 9:15 PM, preetika tyagi <preetikaty...@gmail.com> >> wrote: >> >>> Hi, >>> >>> I'm new to Cassandra and trying to get a better understanding on how the >>> row cache can be tuned to optimize the performance. >>> >>> I came across think this article: https://docs.datastax >>> .com/en/cassandra/3.0/cassandra/operations/opsConfiguringCaches.html >>> >>> And it suggests not to even touch row cache unless read workload is > >>> 95% and mostly rely on machine's default cache mechanism which comes with >>> OS. >>> >>> The default row cache size is 0 in cassandra.yaml file so the row cache >>> won't be utilized at all. >>> >>> Therefore, I'm wondering how exactly I can decide to chose to tweak row >>> cache if needed. Are there any good pointers one can provide on this? >>> >>> Thanks, >>> Preetika >>> >> >> >
