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https://issues.apache.org/jira/browse/HBASE-5259?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phabricator updated HBASE-5259:
-------------------------------
Attachment: D1413.1.patch
Liyin requested code review of "[jira][HBASE-5259] Normalize the RegionLocation
in TableInputFormat by the reverse DNS lookup.".
Reviewers: Kannan, Karthik, mbautin
Assuming the HBase and MapReduce running in the same cluster, the
TableInputFormat is to override the split function which divides all the
regions from one particular table into a series of mapper tasks. So each mapper
task can process a region or one part of a region. Ideally, the mapper task
should run on the same machine on which the region server hosts the
corresponding region. That's the motivation that the TableInputFormat sets the
RegionLocation so that the MapReduce framework can respect the node locality.
The code simply set the host name of the region server as the
HRegionLocation. However, the host name of the region server may have different
format with the host name of the task tracker (Mapper task). The task tracker
always gets its hostname by the reverse DNS lookup. And the DNS service may
return different host name format. For example, the host name of the region
server is correctly set as a.b.c.d while the reverse DNS lookup may return
a.b.c.d. (With an additional doc in the end).
So the solution is to set the RegionLocation by the reverse DNS lookup as
well. No matter what host name format the DNS system is using, the
TableInputFormat has the responsibility to keep the consistent host name format
with the MapReduce framework.
TEST PLAN
running all the unit tests
REVISION DETAIL
https://reviews.facebook.net/D1413
AFFECTED FILES
src/main/java/org/apache/hadoop/hbase/mapreduce/TableInputFormatBase.java
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> Normalize the RegionLocation in TableInputFormat by the reverse DNS lookup.
> ---------------------------------------------------------------------------
>
> Key: HBASE-5259
> URL: https://issues.apache.org/jira/browse/HBASE-5259
> Project: HBase
> Issue Type: Improvement
> Reporter: Liyin Tang
> Assignee: Liyin Tang
> Attachments: D1413.1.patch, D1413.1.patch, D1413.1.patch,
> D1413.1.patch
>
>
> Assuming the HBase and MapReduce running in the same cluster, the
> TableInputFormat is to override the split function which divides all the
> regions from one particular table into a series of mapper tasks. So each
> mapper task can process a region or one part of a region. Ideally, the mapper
> task should run on the same machine on which the region server hosts the
> corresponding region. That's the motivation that the TableInputFormat sets
> the RegionLocation so that the MapReduce framework can respect the node
> locality.
> The code simply set the host name of the region server as the
> HRegionLocation. However, the host name of the region server may have
> different format with the host name of the task tracker (Mapper task). The
> task tracker always gets its hostname by the reverse DNS lookup. And the DNS
> service may return different host name format. For example, the host name of
> the region server is correctly set as a.b.c.d while the reverse DNS lookup
> may return a.b.c.d. (With an additional doc in the end).
> So the solution is to set the RegionLocation by the reverse DNS lookup as
> well. No matter what host name format the DNS system is using, the
> TableInputFormat has the responsibility to keep the consistent host name
> format with the MapReduce framework.
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