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From "Sailesh Mukil (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-4764: Add Hedged read metrics
Date Mon, 15 May 2017 18:36:14 GMT
Sailesh Mukil has posted comments on this change.

Change subject: IMPALA-4764: Add Hedged read metrics
......................................................................


Patch Set 3:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/6886/3/be/src/runtime/disk-io-mgr-scan-range.cc
File be/src/runtime/disk-io-mgr-scan-range.cc:

PS3, Line 349: FLAGS_use_hdfs_pread
> Why not just always get/update the metrics? It still seems valid to me. I a
I agree, however, I did this for perf reasons. The "hdfsGetHedgedReadMetrics" function calls
a malloc every time it's invoked.

I didn't see any reason why we should have it allocate memory and then free it just to get
the same result every time.

What do you think?


http://gerrit.cloudera.org:8080/#/c/6886/3/common/thrift/metrics.json
File common/thrift/metrics.json:

Line 563:     "description": "The total number of hedged reads won over the life of the process",
> , i.e. the number of times hedged reads were faster than the original read 
Done


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Gerrit-MessageType: comment
Gerrit-Change-Id: Id4a5d396abb3373d352ad2df8c2272db018114da
Gerrit-PatchSet: 3
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Sailesh Mukil <sailesh@cloudera.com>
Gerrit-Reviewer: Lars Volker <lv@cloudera.com>
Gerrit-Reviewer: Matthew Jacobs <mj@cloudera.com>
Gerrit-Reviewer: Sailesh Mukil <sailesh@cloudera.com>
Gerrit-HasComments: Yes

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