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From Yan Chunlu <springri...@gmail.com>
Subject sometimes get timeout while batch inserting. (using pycassa)
Date Thu, 20 Sep 2012 10:07:33 GMT
I am testing the performance of 1 cassandra node on a production server.  I
wrote a script to insert 1 million items into cassandra. the data is like
below:

*prefix = "benchmark_"*
*dct = {}*
*for i in range(0,1000000):*
*    key = "%s%d" % (prefix,i)*
*    dct[key] = "abc"*200*

and the inserting code is like this:
*
*
*cf.batch(write_consistency_level = CL_ONEl):*
*cf.insert('%s%s' % (prefix, key),*
*                                              {'value': pickle.dumps(val)},
*
*                                              ttl = None)*


sometimes I get timeout error (detail here:https://gist.github.com/3754965)
 while it's executing. sometime it runs okay.

while the script and cassandra run smoothly on my macbook(for many times),
the configuration of my mac is " 2.4 GHz Intel Core 2 Duo", 8GB memory, SSD
disk though.

really have no idea why is this...

the reason I am do this test is that on the other production server, my 3
nodes cluster also give the pycassa client "timeout" error. make the system
unstable. but I am not sure what the problem is. is it the bug of python
library?
thanks for any further help!

the test script is running on server A and cassandra is running on server
B.
the CPU of B is : "Intel(R) Xeon(R) CPU X3470  @ 2.93GHz Quadcore"

the sys stats on B is normal:

*vmstat 2*
procs -----------memory---------- ---swap-- -----io---- -system--
----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id
wa
 1  0 3643716 134876 191720 2352624    1    1     1    44    0    0 22  3
74  0
 1  0 3643716 132016 191728 2355180    0    0     0   288 4701 16764  9  4
87  0
 0  0 3643716 129700 191736 2357996    0    0     0  5772 3775 17139  9  4
87  0
 0  0 3643716 127468 191744 2360420   32    0    32   404 4490 17487 11  3
85  0
*
*
*iostat -x 2*

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
sda               0.00   230.00    1.00   15.00     6.00   980.00   123.25
    0.03    2.00    8.00    1.60   1.12   1.80
sdb               0.00     0.00    0.00    0.00     0.00     0.00     0.00
    0.00    0.00    0.00    0.00   0.00   0.00

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
          11.52    1.21    1.99    0.48    0.00   84.80

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
sda               7.00   184.00   12.50   12.00    78.00   784.00    70.37
    0.11    4.65    8.32    0.83   1.88   4.60
sdb               0.00     0.00    0.00    0.00     0.00     0.00     0.00
    0.00    0.00    0.00    0.00   0.00   0.00

*free -t*
             total       used       free     shared    buffers     cached
Mem:      16467952   16378592      89360          0     152032    2452216
-/+ buffers/cache:   13774344    2693608
Swap:      7287436    3643716    3643720
Total:    23755388   20022308    3733080

*uptime*
 04:52:57 up 422 days, 19:59,  1 user,  load average: 2.71, 2.09, 1.48

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