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https://issues.apache.org/jira/browse/HBASE-14302?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14710220#comment-14710220
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Matteo Bertozzi commented on HBASE-14302:
-----------------------------------------
I'm not talking about RestoreSnapshotHelper constructor but the method used by
the input format
{code}
+ // we send createBackRefs=false so that restored hfiles do not create back
reference links
+ // in the base hbase root dir.
RestoreSnapshotHelper helper = new RestoreSnapshotHelper(conf, fs,
- manifest, manifest.getTableDescriptor(), restoreDir, monitor, status);
+ manifest, manifest.getTableDescriptor(), restoreDir, monitor, status,
false);
{code}
there are two cases of MR over snapshot. when your snapshot is hosted outside
of the hbase cluster where you should have createBackRefs=False and when you
are on the hbase cluster reading the cluster files, there should be true
otherwise we don't have anything to prevent the user to remove the snapshot and
crash the MR job
> TableSnapshotInputFormat should not create back references when restoring
> snapshot
> ----------------------------------------------------------------------------------
>
> Key: HBASE-14302
> URL: https://issues.apache.org/jira/browse/HBASE-14302
> Project: HBase
> Issue Type: Bug
> Reporter: Enis Soztutar
> Assignee: Enis Soztutar
> Fix For: 2.0.0, 1.2.0, 1.3.0, 1.0.3, 1.1.3
>
> Attachments: hbase-14302_v1.patch
>
>
> TableSnapshotInputFormat restores the snapshot to a temporary directory that
> is outside the HBase's root directory so that it can read from the restored
> snapshot and also refer to hfiles in the actual root directory.
> In restoring the snapshot, we create new hfilelinks in the ephemeral
> location. Creating new hfile links also creates "back references" for GC.
> These back references are dangling since the restore location is outside the
> root dir, and requires a WRITE permission to the root dir (as opposed to just
> READ permission) to be able to run the MR-over-snapshot job.
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