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From "Huaisi Xu (Code Review)" <>
Subject [Impala-ASF-CR] IMPALA-4740: Add option to use hdfsPread() for HDFS hedged reads
Date Sat, 07 Jan 2017 07:27:13 GMT
Huaisi Xu has posted comments on this change.

Change subject: IMPALA-4740: Add option to use hdfsPread() for HDFS hedged reads

Patch Set 2:

> > The HDFS-5776 JIRA mentions that it's implemented for the pread()
 > > code path, but it's not that clear. If you look at the code it's
 > > very clear that it only kicks in on the pread() code path:
 > >
 > >
 > I may be wrong again (as always), hdfspread is not pread. from
 > you can see hdfspread() invokes read(), and hdfsread() calls read()
 > as well, and in turn read() calls pread() as you can see in the
 > link you just quoted. So this new gflag is essentially ignored?
 > What did I miss here?

I missed. it calls a different signature. hdfspread calls read(long position, byte[] buffer,
int offset, int length). thanks for pointing it out..

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Gerrit-MessageType: comment
Gerrit-Change-Id: Iecc8b12aa20cbfe08f4ef6a08a191e49709d9525
Gerrit-PatchSet: 2
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Matthew Jacobs <>
Gerrit-Reviewer: Dan Hecht <>
Gerrit-Reviewer: Huaisi Xu <>
Gerrit-Reviewer: Internal Jenkins
Gerrit-Reviewer: Matthew Jacobs <>
Gerrit-Reviewer: Tim Armstrong <>
Gerrit-HasComments: No

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