[jira] [Commented] (HBASE-10162) Add RegionObserver lifecycle hook to be called when region is available

["Anoop Sam John (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-10162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13847825#comment-13847825 ] 

Anoop Sam John commented on HBASE-10162:
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Thanks Gary for bringing this in.
The term "available" is little bit tricky in case of log replay. Yes the region is available at the time of post open also. But for writes not for reads.  So when the CP developer needs some sort of init wrt writes, will it be correct delaying the init until the log replay is over. In btw writes can happen to region.
Pls correct me if I am wrong Ted/Jefrey.

> Add RegionObserver lifecycle hook to be called when region is available
> -----------------------------------------------------------------------
>
>                 Key: HBASE-10162
>                 URL: https://issues.apache.org/jira/browse/HBASE-10162
>             Project: HBase
>          Issue Type: Improvement
>          Components: Coprocessors
>            Reporter: Gary Helmling
>
> Over in HBASE-10161 and HBASE-10148, there is discussion of the need to modify existing coprocessors, which previously performed initialization only in postOpen(), in order to account for the new log replay mechanism happening post open.
> This points out that we have a hole in coprocessor lifecycle management which caused the use of region lifecycle hooks (postOpen()) in the first place.
> Instead of requiring coprocessor authors to hook into region lifecycle methods for initialization, we should provide an explicit lifecycle hook for coprocessor authors to use when region open, log replay, and any future requirements are complete, say initializeWhenAvailable() (open to better names).



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