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https://issues.apache.org/jira/browse/HBASE-15482?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16281299#comment-16281299
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Ted Yu commented on HBASE-15482:
--------------------------------
{code}
+ public static final String SNAPSHOT_INPUTFORMAT_CARE_BLOCK_LOCALITY_KEY =
"hbase.TableSnapshotInputFormat.locality";
{code}
>From the current key name, it sounds like locality measure (say percent). How
>about naming it "hbase.TableSnapshotInputFormat.locality.enable" (or something
>similar).
{code}
+ List<String> hosts = getBestLocations(conf,
+ HRegion.computeHDFSBlocksDistribution(conf, htd, hri, tableDir));
+
+ // return at most top 3 hosts
+ int len = Math.min(3, hosts.size());
{code}
You can pass 3 to getBestLocations() so that no more than 3 hosts are returned.
> Provide an option to skip calculating block locations for SnapshotInputFormat
> -----------------------------------------------------------------------------
>
> Key: HBASE-15482
> URL: https://issues.apache.org/jira/browse/HBASE-15482
> Project: HBase
> Issue Type: Improvement
> Components: mapreduce
> Reporter: Liyin Tang
> Assignee: Xiang Li
> Priority: Minor
> Fix For: 2.1.0
>
> Attachments: HBASE-15482.master.000.patch
>
>
> When a MR job is reading from SnapshotInputFormat, it needs to calculate the
> splits based on the block locations in order to get best locality. However,
> this process may take a long time for large snapshots.
> In some setup, the computing layer, Spark, Hive or Presto could run out side
> of HBase cluster. In these scenarios, the block locality doesn't matter.
> Therefore, it will be great to have an option to skip calculating the block
> locations for every job. That will super useful for the Hive/Presto/Spark
> connectors.
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