[jira] Commented: (CASSANDRA-646) Fix few minor problems in nodeprobe cfstats

["Jonathan Ellis (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-646?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12792756#action_12792756 ] 

Jonathan Ellis commented on CASSANDRA-646:
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If it times out, there is no data.  Making something up would be nonsensical.

Remember, StorageProxy is the core of the fat client, as well as the server routing.

> Fix few minor problems in nodeprobe cfstats
> -------------------------------------------
>
>                 Key: CASSANDRA-646
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-646
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Tools
>    Affects Versions: 0.5
>            Reporter: Ramzi Rabah
>            Priority: Minor
>
> nodeprobe cfstats reports that readlatency/writelatency is NaN on the keyspace level although it obviously is not.
> For example:
> Keyspace: Keyspace1
>         Read Count: 392
>         Read Latency: NaN ms.
>         Write Count: 262
>         Write Latency: NaN ms.
>         Pending Tasks: 0
>                 Column Family: MyCF
>                 Memtable Columns Count: 143
>                 Memtable Data Size: 123433
>                 Memtable Switch Count: 2
>                 Read Count: 392
>                 Read Latency: 0.533 ms.
>                 Write Count: 262
>                 Write Latency: 0.000 ms.
>                 Pending Tasks: 0
>                 Column Family: Standard2
>                 Memtable Columns Count: 0
>                 Memtable Data Size: 0
>                 Memtable Switch Count: 0
>                 Read Count: 0
>                 Read Latency: NaN ms.
>                 Write Count: 0
>                 Write Latency: NaN ms.
>                 Pending Tasks: 0
> The problem here is that there is more than one cf, and one of them has read latency/writelatency NaN. This causes the keyspace readlatency/writelatency to be NaN instead of the average across all cfs. 
> Another problem with cfstats is that it does not account for the delays when a read/write times out, so it does not accurately reflect the health of the system under too much stress. 

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