[jira] [Commented] (HBASE-14004) [Replication] Inconsistency between Memstore and WAL may result in data in remote cluster that is not in the origin

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

    [ https://issues.apache.org/jira/browse/HBASE-14004?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14977691#comment-14977691 ] 

Heng Chen commented on HBASE-14004:
-----------------------------------

I have a proposal.
When WAL sync failed, and master has to rollback Memstore.  
We can record this action in ZK or system table,  meanwhile all slaves should sync this action and modify its memstore.

Any concerns? 



> [Replication] Inconsistency between Memstore and WAL may result in data in remote cluster that is not in the origin
> -------------------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-14004
>                 URL: https://issues.apache.org/jira/browse/HBASE-14004
>             Project: HBase
>          Issue Type: Bug
>          Components: regionserver
>            Reporter: He Liangliang
>            Priority: Critical
>              Labels: replication, wal
>
> Looks like the current write path can cause inconsistency between memstore/hfile and WAL which cause the slave cluster has more data than the master cluster.
> The simplified write path looks like:
> 1. insert record into Memstore
> 2. write record to WAL
> 3. sync WAL
> 4. rollback Memstore if 3 fails
> It's possible that the HDFS sync RPC call fails, but the data is already  (may partially) transported to the DNs which finally get persisted. As a result, the handler will rollback the Memstore and the later flushed HFile will also skip this record.



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