Does anybody know if it's possible to find out what node a specific key/row
lives on?
We have a 30 node cluster and I'm curious how much faster it'll be to read
data directly from the node that stores the data.
We're using random partitioner, by the way.
*Sameer Farooqui
*Accenture Technology
Each row is stored on RF nodes, and your read will be sent to CL number of
nodes. Messages only take a single hop from the coordinator to each node the
read is performed on, so the networking overhead varies with the number of
nodes involved in the request. There are man factors other than
No problems with read performance, just curious about what kind of overhead
was being added b/c we're doing read tests.
If it's easy to figure out where the row is stored, I'd be interested in
trying it. If not, don't worry about it.
- Sameer
On Wed, Mar 23, 2011 at 4:31 PM, aaron morton
On Wed, Mar 23, 2011 at 4:31 PM, aaron morton aa...@thelastpickle.com wrote:
There are features available to determine which nodes holds replicas for a
particular key. AFAIK they are not intended for use by clients.
Specifically :
The logic to find the node is not complicated. You compute the MD5 hash of
the key. Create sorted list of tokens assigned to the nodes in the ring.
Find the first token greater than the hash. This is the first node. Next in
the list is the replica, which depends on the RF. Now this is simple
