I've not checked the code but from memory when the nodes are ordered in proximity to the coordinator the local node is always first if it's in the replica set. So with RF=3 and N=3 the closest node is always the local one.
Cheers ----------------- Aaron Morton Freelance Cassandra Developer @aaronmorton http://www.thelastpickle.com On 12 Aug 2011, at 10:10, Ian Danforth wrote: > I'm writing at QUORUM though and (pardon me for being dense) it would seem > that the first replica shouldn't always be on the same server if I'm using > RP. > > I very much appreciate your time, I'm sure there is something basic that just > hasn't clicked. > > Ian > > On Thu, Aug 11, 2011 at 2:56 PM, Jonathan Ellis <jbel...@gmail.com> wrote: > https://issues.apache.org/jira/browse/CASSANDRA-2889 > > On Thu, Aug 11, 2011 at 2:55 PM, Ian Danforth <idanfo...@numenta.com> wrote: > > I don't think so, perhaps more succinctly, why would ROW actions only be > > performed on a single node? > > Ian > > > > On Wed, Aug 10, 2011 at 8:12 PM, Jonathan Ellis <jbel...@gmail.com> wrote: > >> > >> are you i/o bound? I believe counter ROW needs to perform a read of > >> the old value. > >> > >> On Wed, Aug 10, 2011 at 7:17 PM, Ian Danforth <idanfo...@numenta.com> > >> wrote: > >> > Hello all! > >> > Thanks for taking the time to read this, I'm new to Cassandra and really > >> > want to get it working :) > >> > Below you'll find the output from tpstats on the three nodes in my .8.1 > >> > cluster. As you'll note from ring (also below), my cluster appears > >> > balanced. > >> > However, please note that NODE1 is the only node that has completed any > >> > ReplicateOnWriteStage actions. I've been having a lot of trouble with > >> > RoW > >> > and seen a single node in my various test clusters get hugely backed up > >> > on > >> > this stage to the point where it slows all writes to a crawl. > >> > I'm using counters in a column family defined like this: > >> > ==== KEYSPACE/CF ==== > >> > create keyspace Keyspace1 > >> > with strategy_options=[{replication_factor:3}] > >> > and placement_strategy = > >> > 'org.apache.cassandra.locator.SimpleStrategy'; > >> > use Keyspace1; > >> > create column family TwitterTest > >> > with default_validation_class = CounterColumnType > >> > and replicate_on_write = true; > >> > ==== > >> > > >> > With any given batch_insert() I'm incrementing ~17,000 counters. I've > >> > backed > >> > off a bit and started using ConsistencyLevel.QUORUM, as it was suggested > >> > elsewhere that ANY or ONE could overwhelm the system. > >> > > >> > I hope I'm just doing something stupid and one you experienced folks can > >> > point out my error. > >> > Thanks in advance! > >> > Ian > >> > ==== MORE DATA ==== > >> > Address DC Rack Status State Load > >> > Owns > >> > Token > >> > > >> > 113427455640312821154458202477256070484 > >> > 10.87.9.57 datacenter1 rack1 Up Normal 193.86 MB > >> > 33.33% 0 > >> > 10.86.223.32 datacenter1 rack1 Up Normal 191.1 MB > >> > 33.33% 56713727820156410577229101238628035242 > >> > 10.86.229.24 datacenter1 rack1 Up Normal 193.63 MB > >> > 33.33% 113427455640312821154458202477256070484 > >> > > >> > > >> > > >> > SEED > >> > Pool Name Active Pending Completed > >> > ReadStage 0 0 7 > >> > RequestResponseStage 0 0 1479839 > >> > MutationStage 0 0 1479908 > >> > ReadRepairStage 0 0 0 > >> > ReplicateOnWriteStage 0 0 0 > >> > GossipStage 0 0 5176 > >> > AntiEntropyStage 0 0 0 > >> > MigrationStage 0 0 128 > >> > MemtablePostFlusher 0 0 28 > >> > StreamStage 0 0 0 > >> > FlushWriter 0 0 28 > >> > MiscStage 0 0 2 > >> > FlushSorter 0 0 0 > >> > InternalResponseStage 0 0 363 > >> > HintedHandoff 0 0 0 > >> > NODE1 > >> > Pool Name Active Pending Completed > >> > ReadStage 0 0 7 > >> > RequestResponseStage 0 0 2960208 > >> > MutationStage 0 0 1480104 > >> > ReadRepairStage 0 0 0 > >> > ReplicateOnWriteStage 0 0 1480104 > >> > GossipStage 0 0 4151 > >> > AntiEntropyStage 0 0 0 > >> > MigrationStage 0 0 128 > >> > MemtablePostFlusher 0 0 31 > >> > StreamStage 0 0 8 > >> > FlushWriter 0 0 31 > >> > MiscStage 0 0 8 > >> > FlushSorter 0 0 0 > >> > InternalResponseStage 0 0 1 > >> > HintedHandoff 0 0 0 > >> > NODE2 > >> > Pool Name Active Pending Completed > >> > ReadStage 0 0 7 > >> > RequestResponseStage 0 0 0 > >> > MutationStage 0 0 1481530 > >> > ReadRepairStage 0 0 0 > >> > ReplicateOnWriteStage 0 0 0 > >> > GossipStage 0 0 4201 > >> > AntiEntropyStage 0 0 0 > >> > MigrationStage 0 0 128 > >> > MemtablePostFlusher 0 0 31 > >> > StreamStage 0 0 6 > >> > FlushWriter 0 0 31 > >> > MiscStage 0 0 6 > >> > FlushSorter 0 0 0 > >> > InternalResponseStage 0 0 1 > >> > HintedHandoff 0 0 0 > >> > >> > >> > >> -- > >> Jonathan Ellis > >> Project Chair, Apache Cassandra > >> co-founder of DataStax, the source for professional Cassandra support > >> http://www.datastax.com > > > > > > > > -- > Jonathan Ellis > Project Chair, Apache Cassandra > co-founder of DataStax, the source for professional Cassandra support > http://www.datastax.com >
