[jira] [Commented] (HBASE-15016) StoreServices facility in Region

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

    [ https://issues.apache.org/jira/browse/HBASE-15016?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15084048#comment-15084048 ] 

stack commented on HBASE-15016:
-------------------------------

Thank you for the paper explaining the thresholds. Nothing surprising. I think its just a matter of nomenclature and then not changing semantic of currently defined configs. Also, why can't it be that the Region just flags the Stores when region memory use hits a threshold -- say half or 2/3rds -- with a 'warning' that a flush is on the way, then internal to the Store, you start up your segment stuff. Let the store size usage grow and shrink but purge notions of 'active' -- it is all active memory whether used by memstore, segments or snapshots -- and 'fluctuating', it is all fluctuating memory as flushes come and go (i showed the fluctuating and active naming to a coworker and he was also baffled by what is intended and starting talking of high and low level water marks).

> StoreServices facility in Region
> --------------------------------
>
>                 Key: HBASE-15016
>                 URL: https://issues.apache.org/jira/browse/HBASE-15016
>             Project: HBase
>          Issue Type: Sub-task
>            Reporter: Eshcar Hillel
>            Assignee: Eshcar Hillel
>         Attachments: HBASE-15016-V01.patch, HBASE-15016-V02.patch, HBASE-15016-V03.patch, Regioncounters.pdf
>
>
> The default implementation of a memstore ensures that between two flushes the memstore size increases monotonically. Supporting new memstores that store data in different formats (specifically, compressed), or that allows to eliminate data redundancies in memory (e.g., via compaction), means that the size of the data stored in memory can decrease even between two flushes. This requires memstores to have access to facilities that manipulate region counters and synchronization.
> This subtasks introduces a new region interface -- StoreServices, through which store components can access these facilities.



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