My best advice on this is, insert a bit of data into the tree, and then do a
heap dump to calculate the extra overhead. It's unfortunately more than you
would like from our testing.
On Tue, Oct 18, 2011 at 8:14 PM, Todd Nine t...@spidertracks.com wrote:
**
Hi guys,
We've just built a K tree implementation in cassandra. We're going for
relatively wide nodes in our tree to minimize our tree depth and increase
our search times. Most of the links between parent/child nodes are longs.
We're ready to start tuning the size of K so that our most access paths in
our tree will be row cached in Cassandra. We're on Cassandra 0.8.7, and I
can't find any documentation regarding the actual memory size of the off
heap row cache. Can someone explain how much additional space will be used
when caching rows? For instance, if our links between nodes are all Longs,
and we have 100 children (cols), that gives us 900 bytes with a 0 byte
placeholder value. What is the additional overhead when using the off heap
storage?
Thanks,
Todd