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From aaron morton <aa...@thelastpickle.com>
Subject Re: tpstats confusion
Date Fri, 12 Aug 2011 01:38:55 GMT
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 <jbellis@gmail.com> wrote:
> https://issues.apache.org/jira/browse/CASSANDRA-2889
> 
> On Thu, Aug 11, 2011 at 2:55 PM, Ian Danforth <idanforth@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 <jbellis@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 <idanforth@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
> 


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