Some bug was fixed in 2.0.0-beta2 by C* developers. Try it!


2013/7/22 Andrew Cobley <a.e.cobley@dundee.ac.uk>
I've been noticing some strange casandra-stress results with 2.0.0 beta 1.  I've set up a single node on a Mac (4 gig ram, 2.8Ghz core 2 duo) and installed 2.0.0 beta1. 

When I run ./cassandra-stress  -d 134.36.36.218 I'm seeing the interval-op-rate drop from a peek of 11562 at the start to 0 -20 after about 358 seconds.  Here's the output:

./cassandra-stress  -d 134.36.36.218
Created keyspaces. Sleeping 1s for propagation.
total,interval_op_rate,interval_key_rate,latency,95th,99th,elapsed_time
13629,1362,1362,15.3,117.6,531.1,10
37545,2391,2391,9.4,74.0,438.4,20
105410,6786,6786,3.3,38.0,216.4,30
209014,10360,10360,2.7,26.2,216.5,41
320024,11101,11101,2.5,14.5,216.5,51
430216,11019,11019,2.4,10.5,215.4,61
531905,10168,10168,2.4,8.3,177.1,72
619672,8776,8776,2.4,6.2,145.8,82
653977,3430,3430,2.4,5.9,145.4,92
682648,2867,2867,2.4,6.1,145.4,102
692771,1012,1012,2.4,6.1,145.4,113
712163,1939,1939,2.4,6.0,4461.7,123
723761,1159,1159,2.4,6.0,4461.7,133
731115,735,735,2.4,6.1,4461.7,143
737627,651,651,2.4,6.2,4461.7,153
743853,622,622,2.4,7.0,5056.1,164
747345,349,349,2.4,7.0,5056.1,174
755501,815,815,2.5,6.9,6351.7,184
758692,319,319,2.5,6.9,5056.1,195
763960,526,526,2.5,7.3,5292.6,205
767966,400,400,2.5,7.4,5292.6,215
769514,154,154,2.5,7.4,5292.6,225
773492,397,397,2.5,7.2,6435.7,236
775374,188,188,2.5,7.4,5292.6,246
776035,66,66,2.6,7.5,5347.1,256
777896,186,186,2.6,7.9,6407.3,266
778791,89,89,2.6,8.0,6438.9,276
779646,85,85,2.6,8.0,6523.2,287
780785,113,113,2.6,11.1,6523.2,297
781336,55,55,2.6,11.7,6523.2,307
781684,34,34,2.6,13.3,16734.0,317
781818,13,13,2.7,13.9,16764.2,328
781952,13,13,2.7,13.9,16900.1,338
782195,24,24,2.7,15.3,16900.1,348
782294,9,9,2.7,15.3,16900.1,358
782362,6,6,2.7,15.5,21487.3,368
782589,22,22,2.7,20.1,21487.3,379
782775,18,18,2.7,28.8,21487.3,389
783012,23,23,2.8,29.4,21487.3,399
783248,23,23,2.8,68.2,21487.3,409
783270,2,2,2.8,68.2,21487.3,419
783283,1,1,2.8,68.2,21487.3,430
783283,0,0,2.8,68.2,21487.3,440
783337,5,5,2.8,198.6,42477.2,450
783492,15,15,2.9,5057.6,52687.3,460
783581,8,8,2.9,5349.0,59306.9,471
783807,22,22,3.0,6429.1,59306.9,481
783816,0,0,3.0,6438.3,59306.9,491
783945,12,12,3.2,11566.9,59306.9,501
783962,1,1,3.2,11612.0,59306.9,512
783962,0,0,3.2,11612.0,59306.9,522


I installed 1.2.6 for comparision and that gave  expected results:

./cassandra-stress  -d 134.36.36.218
Unable to create stress keyspace: Keyspace names must be case-insensitively unique ("Keyspace1" conflicts with "Keyspace1")
total,interval_op_rate,interval_key_rate,latency/95th/99th,elapsed_time
22158,2215,2215,0.8,8.9,549.0,10
64192,4203,4203,1.0,7.0,486.2,20
114236,5004,5004,1.3,6.5,411.9,30
178407,6417,6417,1.4,5.5,411.9,40
281714,10330,10330,2.2,5.1,409.6,51
371684,8997,8997,2.4,5.1,407.5,61
464401,9271,9271,2.5,5.0,236.7,72
562797,9839,9839,2.6,5.2,87.5,82
655755,9295,9295,2.6,5.2,87.5,92
751560,9580,9580,2.6,4.7,179.9,103
848022,9646,9646,2.6,4.5,826.0,113
914539,6651,6651,2.6,4.7,823.2,123
1000000,8546,8546,2.6,5.1,1048.5,133

Any ideas whats causing the slow down ?

Andy


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