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.
