Tim Armstrong has posted comments on this change.

Change subject: IMPALA-5511: Add process start time to debug web page
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Patch Set 1:

(2 comments)

The overall approach seems good, but I had some concerns about the 
ReadProcStartTime() implementation.

http://gerrit.cloudera.org:8080/#/c/7363/1/be/src/util/process-state-info.cc
File be/src/util/process-state-info.cc:

Line 175:   const string& command = Substitute(
We're adding a runtime dependence on some additional command-line utilities, 
which seems brittle. I'm not really sure which versions of these utilities 
support which arguments, etc. We really want to avoid forking processes after 
start, since it can cause big spikes in virtual memory usage, e.g. see 
IMPALA-2294

It seems like we can get the same info directly from stat(): 
http://pubs.opengroup.org/onlinepubs/009695399/functions/stat.html then format 
it with strftime() or similar.


PS1, Line 176:  /proc/$0/
Is the ctime of this directory documented to be the process start time?

It looks like it matches on my system but if there's some official 
documentation it would be good to reference.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I05ae2f80835b1b0e4bc3b38731778ba0871338a4
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Gabor Kaszab <[email protected]>
Gerrit-Reviewer: Attila Jeges <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Henry Robinson <[email protected]>
Gerrit-Reviewer: Laszlo Gaal <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-HasComments: Yes

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