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https://issues.apache.org/jira/browse/HBASE-8369?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Enis Soztutar updated HBASE-8369:
---------------------------------
Release Note:
Added TableSnapshotInputFormat and TableSnapshotScanner for performing scans
over hbase table snapshots from the client side, bypassing the hbase servers.
The former configures a mapreduce job, while the latter does single client side
scan over snapshot files. Can also be used with offline HBase with in-place or
exported snapshot files.
WARNING: This feature bypasses HBase-level security completely since the files
are read from the hdfs directly. The user who is running the scan / job has to
have read permissions to the data files and snapshot files.
> 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
>
> Attachments: HBASE-8369-0.94.patch, HBASE-8369-0.94_v2.patch,
> HBASE-8369-0.94_v3.patch, HBASE-8369-0.94_v4.patch, HBASE-8369-0.94_v5.patch,
> HBASE-8369-trunk_v1.patch, HBASE-8369-trunk_v2.patch,
> HBASE-8369-trunk_v3.patch, hbase-8369_v0.patch, hbase-8369_v5.patch,
> hbase-8369_v6.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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