[jira] [Commented] (HBASE-4089) blockCache contents report

["Doug Meil (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-4089?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13072809#comment-13072809 ] 

Doug Meil commented on HBASE-4089:
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Regarding dumping the summary report to the log, I think exposing a public 'printSummary' (logSummary?) method on LruBlockCache would do it.  Another thread can take care of the scheduling on how often the block cache summary should be run.



> blockCache contents report
> --------------------------
>
>                 Key: HBASE-4089
>                 URL: https://issues.apache.org/jira/browse/HBASE-4089
>             Project: HBase
>          Issue Type: New Feature
>            Reporter: Doug Meil
>
> Summarized block-cache report for a RegionServer would be helpful.  For example ...
> table1
>   cf1   100 blocks, totalBytes=yyyyy, averageTimeInCache=XXXX hours
>   cf2   200 blocks, totalBytes=zzzzz, averageTimeInCache=XXXX hours
> table2
>   cf1  75 blocks, totalBytes=yyyyy, averageTimeInCache=XXXX hours
>   cf2 150 blocks, totalBytes=zzzzz, averageTimeInCache=XXXX hours
> ... Etc.
> The current metrics list blockCacheSize and blockCacheFree, but there is no way to know what's in there.  Any single block isn't really important, but the patterns of what CF/Table they came from, how big are they, and how long (on average) they've been in the cache, are important.
> No such interface exists in HRegionInterface.  But I think it would be helpful from an operational perspective.
> Updated (7-29):  Removing suggestion for UI.  I would be happy just to get this report on a configured interval dumped to a log file.

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