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https://issues.apache.org/jira/browse/HBASE-8369?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13848504#comment-13848504
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Lars Hofhansl commented on HBASE-8369:
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These seems inmportant:
bq. TableMapreduceUtil changes (other than the new method): needed in case
security is enabled. We should not talk with the HBase cluster at all.
bq. HDFSBlocksDistribution: in v3, we are providing 3 servers with highest
locality to the input split. In v11, we are using all the servers with 80% of
the locality for the top locality server. This ensures better locality.
This seems nice to have:
bq. ClientScanner / AbstractClientScanner / TableRecordReaderImpl changes: the
ClientSideRegion scanner keeps track of ScanMetrics, and exports those via MR
job counters or Scan.
To track what/how the mappers are doing.
The rest we can do without in 0.94. Let's also move the discussion to
HBASE-10076.
> 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_v11.patch,
> hbase-8369_v5.patch, hbase-8369_v6.patch, hbase-8369_v7.patch,
> hbase-8369_v8.patch, hbase-8369_v9.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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