[jira] [Commented] (HBASE-10241) implement mvcc-consistent scanners (across recovery)

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

    [ https://issues.apache.org/jira/browse/HBASE-10241?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13857348#comment-13857348 ] 

Sergey Shelukhin commented on HBASE-10241:
------------------------------------------

one-pager doesn't cover merges and splits. Looks like mvccs on client will have to be tracked per range, rather than region.
For even more consistent scanner, mvccs might even optionally be pre-fetched from all regions, but that is for later

> implement mvcc-consistent scanners (across recovery)
> ----------------------------------------------------
>
>                 Key: HBASE-10241
>                 URL: https://issues.apache.org/jira/browse/HBASE-10241
>             Project: HBase
>          Issue Type: New Feature
>          Components: HFile, regionserver, Scanners
>    Affects Versions: 0.99.0
>            Reporter: Sergey Shelukhin
>            Assignee: Sergey Shelukhin
>         Attachments: Consistent scanners.pdf
>
>
> Scanners currently use mvcc for consistency. However, mvcc is lost on server restart, or even a region move. This JIRA is to enable the scanners to transfer mvcc (or seqId, or some other number, see HBASE-8763) between servers. First, client scanner needs to get and store the readpoint. Second, mvcc needs to be preserved in WAL. Third, the mvcc needs to be stored in store files per KV and discarded when not needed.



--
This message was sent by Atlassian JIRA
(v6.1.5#6160)