[jira] [Updated] (HBASE-6423) Writes should not block reads on blocking updates to memstores

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

     [ https://issues.apache.org/jira/browse/HBASE-6423?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jimmy Xiang updated HBASE-6423:
-------------------------------

    Attachment: trunk-6423.patch
    
> Writes should not block reads on blocking updates to memstores
> --------------------------------------------------------------
>
>                 Key: HBASE-6423
>                 URL: https://issues.apache.org/jira/browse/HBASE-6423
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Karthik Ranganathan
>            Assignee: Amitanand Aiyer
>         Attachments: trunk-6423.patch
>
>
> We have a big data use case where we turn off WAL and have a ton of reads and writes. We found that:
> 1. flushing a memstore takes a while (GZIP compression)
> 2. incoming writes cause the new memstore to grow in an unbounded fashion
> 3. this triggers blocking memstore updates
> 4. in turn, this causes all the RPC handler threads to block on writes to that memstore
> 5. we are not able to read during this time as RPC handlers are blocked
> At a higher level, we should not hold up the RPC threads while blocking updates, and we should build in some sort of rate control.

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