[jira] Commented: (HBASE-2477) Slowly changing column family or table could cause accumulation of logs & substantially increase recovery times

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

    [ https://issues.apache.org/jira/browse/HBASE-2477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12859932#action_12859932 ] 

stack commented on HBASE-2477:
------------------------------

That'd be fine.

There is also the mechanism whereby if count of HLogs > some configurable amount, we start flushing memstore that holds oldest edits.  This works in some regard but not well enough in your case?

> Slowly changing column family or table could cause accumulation of logs & substantially increase recovery times
> ---------------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-2477
>                 URL: https://issues.apache.org/jira/browse/HBASE-2477
>             Project: Hadoop HBase
>          Issue Type: Bug
>            Reporter: Kannan Muthukkaruppan
>
> Memstore flushes are triggered today if a memstore exceeds a certain size or there is memory pressure.  However, there is no timer based flush for a memstore. This means a single column family or table getting a very slow rate of writes could hold up old HLogs from getting reclaimed for long periods of time-- which in turn increases recovery time for a failed region server since there are a lot more logs to process.
> META is an example of a table which is likely to get very few writes. But even if we special cased META somehow, it wouldn't be good enough, since an application could genuinely have a mix of slow and fast changing tables or column families.
> What about also triggering flushes on a timer (in addition to the current mechanism) to bound recovery times?

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.