[jira] [Commented] (HBASE-8369) MapReduce over snapshot files

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

    [ https://issues.apache.org/jira/browse/HBASE-8369?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13634533#comment-13634533 ] 

Lars Hofhansl commented on HBASE-8369:
--------------------------------------

That sounds awesome. All new code, I assume, so I'd be OK with this in 0.94 as well (but I don't have a strong preference).
                
> MapReduce over snapshot files
> -----------------------------
>
>                 Key: HBASE-8369
>                 URL: https://issues.apache.org/jira/browse/HBASE-8369
>             Project: HBase
>          Issue Type: New Feature
>          Components: mapreduce, snapshots
>            Reporter: Enis Soztutar
>            Assignee: Enis Soztutar
>             Fix For: 0.98.0, 0.95.2
>
>         Attachments: hbase-8369_v0.patch
>
>
> The idea is to add an InputFormat, which can run the mapreduce job over snapshot files directly bypassing hbase server layer. The IF is similar in usage to TableInputFormat, taking a Scan object from the user, but instead of running from an online table, it runs from a table snapshot. We do one split per region in the snapshot, and open an HRegion inside the RecordReader. A RegionScanner is used internally for doing the scan without any HRegionServer bits. 
> Users have been asking and searching for ways to run MR jobs by reading directly from hfiles, so this allows new use cases if reading from stale data is ok:
>  - Take snapshots periodically, and run MR jobs only on snapshots.
>  - Export snapshots to remote hdfs cluster, run the MR jobs at that cluster without HBase cluster.
>  - (Future use case) Combine snapshot data with online hbase data: Scan from yesterday's snapshot, but read today's data from online hbase cluster. 

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