I have both row cache and column cache disabled for all my CFs. cfstats says "Bloom Filter Space Used: 1760" per CF. Assuming it is in bytes, it is total of about 9MB of bloom filter size for 5K CFs; which is not a lot.
On Tue, Mar 20, 2012 at 11:09 AM, Vitalii Tymchyshyn <tiv...@gmail.com> wrote: > Hello. > > From my experience it's unwise to make many column families for same keys > because you will have bloom filters and row indexes multiplied. If you have > 5000, you should expect your heap requirements multiplied by same factor. > Also check your cache sizes. Default AFAIR is 100000 keys per column family. > > 20.03.12 16:05, A J написав(ла): > >> ok, the last thread says that 1.0+ onwards, thousands of CFs should >> not be a problem. >> >> But I am finding that all the allocated heap memory is getting consumed. >> I started with 8GB heap and then on reading >> >> http://www.datastax.com/dev/blog/whats-new-in-cassandra-1-0-improved-memory-and-disk-space-management >> realized that minimum of 1MB per memtable is used by the per-memtable >> arena allocator. >> So with 5K CFs, 5GB will be used just by arena allocators. >> >> But even on increasing the heap to 16GB, am finding that all the heap >> is getting consumed. Is there a different formula for heap calculation >> when you have thousands of CFs ? >> Any other configuration that I need to change ? >> >> Thanks. >> >> On Mon, Mar 19, 2012 at 10:35 AM, Alain RODRIGUEZ<arodr...@gmail.com> >> wrote: >>> >>> This subject was already discussed, this may help you : >>> >>> http://markmail.org/message/6dybhww56bxvufzf#query:+page:1+mid:6dybhww56bxvufzf+state:results >>> >>> If you still got questions after reading this thread or some others about >>> the same topic, do not hesitate asking again, >>> >>> Alain >>> >>> >>> 2012/3/19 A J<s5a...@gmail.com> >>>> >>>> How many Column Families are one too many for Cassandra ? >>>> I created a db with 5000 CFs (I can go into the reasons later) but the >>>> latency seems to be very erratic now. Not sure if it is because of the >>>> number of CFs. >>>> >>>> Thanks. >>> >>> >
