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https://issues.apache.org/jira/browse/HBASE-18090?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
xinxin fan updated HBASE-18090:
-------------------------------
Release Note:
In this task, we make it possible to run multiple mappers per region in the
table snapshot.
The following code is primary table snapshot mapper initializatio:
TableMapReduceUtil.initTableSnapshotMapperJob(
snapshotName, // The name of the snapshot (of a
table) to read from
scan, // Scan instance to
control CF and attribute selection
mapper, // mapper
outputKeyClass, // mapper output key
outputValueClass, // mapper output value
job, // The current job to
adjust
true, // upload HBase jars and
jars for any of the configured job classes via the distributed cache (tmpjars)
restoreDir, // a temporary directory to
copy the snapshot files into
);
The job only run one map task per region in the table snapshot. With this
feature, client can specify the desired num of mappers when init table snapshot
mapper job：
TableMapReduceUtil.initTableSnapshotMapperJob(
snapshotName, // The name of the snapshot (of a
table) to read from
scan, // Scan instance to
control CF and attribute selection
mapper, // mapper
outputKeyClass, // mapper output key
outputValueClass, // mapper output value
job, // The current job to
adjust
true, // upload HBase jars and
jars for any of the configured job classes via the distributed cache (tmpjars)
restoreDir, // a temporary directory to
copy the snapshot files into
splitAlgorithm, // splitAlgo algorithm to split,
current split algorithms only support RegionSplitter.UniformSplit() and
RegionSplitter.HexStringSplit()
n // how many input splits to
generate per one region
);
was:
In this task, we make it possible to run multiple mappers per region in the
table snapshot. With this feature, client can specify the desired num of
mappers when init table snapshot mapper job：
TableMapReduceUtil.initTableSnapshotMapperJob(
snapshotName, // The name of the snapshot (of a
table) to read from
scan, // Scan instance to
control CF and attribute selection
mapper, // mapper
outputKeyClass, // mapper output key
outputValueClass, // mapper output value
job, // The current job to
adjust
true, // upload HBase jars and
jars for any of the configured job classes via the distributed cache (tmpjars)
restoreDir, // a temporary directory to
copy the snapshot files into
splitAlgorithm, // splitAlgo algorithm to split,
current split algorithms only support RegionSplitter.UniformSplit() and
RegionSplitter.HexStringSplit()
n // how many input splits to
generate per one region
);
> Improve TableSnapshotInputFormat to allow more multiple mappers per region
> --------------------------------------------------------------------------
>
> Key: HBASE-18090
> URL: https://issues.apache.org/jira/browse/HBASE-18090
> Project: HBase
> Issue Type: Improvement
> Components: mapreduce
> Reporter: Mikhail Antonov
> Assignee: xinxin fan
> Fix For: 2.0.0-beta-1
>
> Attachments: HBASE-18090-V3-master.patch,
> HBASE-18090-V4-master.patch, HBASE-18090-V5-master.patch,
> HBASE-18090-branch-1-v2.patch, HBASE-18090-branch-1-v2.patch,
> HBASE-18090-branch-1.3-v1.patch, HBASE-18090-branch-1.3-v2.patch,
> HBASE-18090.branch-1.patch
>
>
> TableSnapshotInputFormat runs one map task per region in the table snapshot.
> This places unnecessary restriction that the region layout of the original
> table needs to take the processing resources available to MR job into
> consideration. Allowing to run multiple mappers per region (assuming
> reasonably even key distribution) would be useful.
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