Hi, Are there any blogs/writeups anyone is aware of that talks of using primary replica as coordinator node (rather than a random coordinator node) in production scenarios ?
Thank you. On Wed, Feb 16, 2011 at 10:53 AM, A J <s5a...@gmail.com> wrote: > Thanks for the confirmation. Interesting alternatives to avoid random > coordinator. > Are there any blogs/writeups of they (primary node as co-ordinator) been > used in production scenarios. I googled but could not find anything > relevant. > On Wed, Feb 16, 2011 at 3:25 AM, Oleg Anastasyev <olega...@gmail.com> wrote: >> >> A J <s5alye <at> gmail.com> writes: >> >> > >> > >> > Makes sense ! Thanks. >> > Just a quick follow-up: >> > Now I understand the write is not made to coordinator (unless it is part >> > of >> the replica for that key). But does the write column traffic 'flow' >> through the >> coordinator node. For a 2G column write, will I see 2G network traffic on >> the >> coordinator node or just a few bytes of traffic on the co-ordinator of it >> reading the key and talking to nodes/client etc ? >> >> Yes, if you talk to random (AKA coordinator) node first - all 2G traffic >> will >> flow to it first and then forwarded to natural nodes (those owning >> replicas of a >> row to be written). >> If you want to avoid extra traffic, you should determine natural nodes of >> the >> row and send your write directly to one of natural nodes (i.e. one of >> natural >> nodes became coordinator). This natural coordinator node will accept write >> locally and submit write to other replicas in parallel. >> If your client is written in java this can be implemented relatively easy. >> Look >> at TokenMetadata.ringIterator(). >> >> If you have no requirement on using thrift interface of cassandra, it >> could be >> more efficient to write using StorageProxy interface. The latter plays a >> local >> coordinator role, so it talks directly to all replicas, so these 2G will >> be >> passed directly from your client to all row replicas. >> >> >> > >> > This will be a factor for us. So need to make sure exactly. >> >> > >
