[jira] Commented: (CASSANDRA-406) SSTable File Metrics per CF

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

    [ https://issues.apache.org/jira/browse/CASSANDRA-406?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12750064#action_12750064 ] 

Jonathan Ellis commented on CASSANDRA-406:
------------------------------------------

so there are a couple metrics that could be useful:

 - ssTables.size() -- if this is over a few dozen something is wrong 
 - the total size of each data directory, including filter and index files -- tells us if we're running out of space
 - the average size and count of the sstables as bucketized by getCompactionBuckets -- tells us if compaction bucketing is working as expected

These are things we can graph easily (with the possible exception of #3 -- but that would be a cool histogram to have) and get value out of...  I don't see knowing the size of an individual sstable being valuable though.

I'm not convinced the lock counter is useful in general, but it's worth trying out internally to see if it adds to your insight into the system.  But if it basically just mirrors read latency then I don't think we need it.

> SSTable File Metrics per CF
> ---------------------------
>
>                 Key: CASSANDRA-406
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-406
>             Project: Cassandra
>          Issue Type: New Feature
>    Affects Versions: 0.5
>            Reporter: Chris Goffinet
>            Assignee: Sammy Yu
>            Priority: Minor
>             Fix For: 0.5
>
>         Attachments: 0001-Expose-out-queue-length-of-sstable-lock-in-MBean-int.patch
>
>
> We should add sstable-physical-files per CF in cfstats mbean

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