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From Brian Tarbox <tar...@cabotresearch.com>
Subject Re: cfhistograms
Date Mon, 25 Mar 2013 16:36:48 GMT
I think we all go through this learning curve.  Here is the answer I gave
last time this question was asked:

The output of this command seems to make no sense unless I think of it as 5
completely separate histograms that just happen to be displayed together.

Using this example output should I read it as: my reads all took either 1
or 2 sstable.  And separately, I had write latencies of 3,7,19.  And
separately I had read latencies of 2, 8,69, etc?

In other words...each row isn't really a row...i.e. on those 16033 reads
from a single SSTable I didn't have 0 write latency, 0 read latency, 0 row
size and 0 column count.  Is that right?

Offset      SSTables     Write Latency      Read Latency          Row Size
     Column Count
1              16033             0                            0
               0                 0
2                303               0                            0
                 0                 1
3                  0                 0                            0
                   0                 0
4                  0                 0                            0
                   0                 0
5                  0                 0                            0
                   0                 0
6                  0                 0                            0
                   0                 0
7                  0                 0                            0
                   0                 0
8                  0                 0                            2
                   0                 0
10                 0                 0                            0
                   0              6261
12                 0                 0                            2
                   0               117
14                 0                 0                            8
                   0                 0
17                 0                 3                           69
                   0               255
20                 0                 7                          163
                   0                 0
24                 0                19                         1369
                   0                 0


On Mon, Mar 25, 2013 at 11:52 AM, Kanwar Sangha <kanwar@mavenir.com> wrote:

>  Can someone explain how to read the cfhistograms o/p ?****
>
> ** **
>
> [root@db4 ~]# nodetool cfhistograms usertable data****
>
> usertable/data histograms****
>
> Offset      SSTables     Write Latency      Read Latency          Row
> Size      Column Count****
>
> 1            2857444              4051                 0
> 0                             342711****
>
> 2            6355104             27021                 0
>    0                                          201313****
>
> 3            2579941             61600                 0
> 0                                          130489****
>
> 4             374067            119286                 0
> 0             91378****
>
> 5               9175            210934                 0
> 0             68548****
>
> 6                  0            321098                 0
> 0             54479****
>
> 7                  0            476677                 0
> 0             45427****
>
> 8                  0            734846                 0
> 0             38814****
>
> 10                 0           2867967                 4
> 0             65512****
>
> 12                 0           5366844                22
> 0             59967****
>
> 14                 0           6911431                36
> 0             63980****
>
> 17                 0          10155740               127
> 0            115714****
>
> 20                 0           7432318               302
>   0            138759****
>
> 24                 0           5231047               969
> 0            193477****
>
> 29                 0           2368553              2790
> 0            209998****
>
> 35                 0            859591              4385
> 0            204751****
>
> 42                 0            456978              3790
> 0            214658****
>
> 50                 0            306084              2465
> 0            151838****
>
> 60                 0            223202              2158
> 0             40277****
>
> 72                 0            122906              2896
> 0              1735****
>
> ** **
>
> ** **
>
> Thanks****
>
> Kanwar****
>
> ** **
>

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