[jira] Commented: (HBASE-2162) scanners need to obey row locks, a modest propsal

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

    [ https://issues.apache.org/jira/browse/HBASE-2162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12803963#action_12803963 ] 

stack commented on HBASE-2162:
------------------------------

See hbase-1806.  There we allowed that scanners did not respect row locks and doc'd that this was the case.

> scanners need to obey row locks, a modest propsal
> -------------------------------------------------
>
>                 Key: HBASE-2162
>                 URL: https://issues.apache.org/jira/browse/HBASE-2162
>             Project: Hadoop HBase
>          Issue Type: Bug
>            Reporter: ryan rawson
>            Assignee: ryan rawson
>             Fix For: 0.21.0
>
>
> 15:54 < dj_ryan> - next:
> 15:54 < dj_ryan> do next on Tree in memstore get rowid
> 15:55 < dj_ryan> acquire read lock on rowid (wait if necessary)
> 15:55 < dj_ryan> snapshot the entire row worth of data from memstore into scanner
> 15:55 < dj_ryan> release read lock on rowid
> 15:56 < dj_ryan> so if we get an insert on a row after the 'do next' which would call 'next' on the 
>                  previous last value grabbed from the tree
> 15:56 < dj_ryan> we'd skip that one
> 15:56 < dj_ryan> which is fine
> 15:57 < dj_ryan> i guess the issue comes in when you have to next a bunch to get to the next row
> 15:57 < dj_ryan> but that is doable with a simple little while loop
> 15:57 < dj_ryan> this only applies to memstore
> 15:57 < dj_ryan> snapshot = hfile 
> 15:57 < dj_ryan> since its immutable

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