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From Michael Pearce <Michael.Pea...@ig.com>
Subject Re: s/gettimeofday/clock_gettime/ in hawq?
Date Mon, 24 Apr 2017 07:40:41 GMT
Hi,

clock_gettime i believe was made native available in macOS Sierra (10.12).

prior versions though don't afaik. Though with the aggressive upgrade of OSX on apple devices
that apple push, to end users is this really a concern?

As per posix guidance also, what you suggest is also recommended as gettimeofday is obsolescent.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/gettimeofday.html

Regards
Mike

________________________________________
From: Paul Guo <paulguo@gmail.com>
Sent: Monday, April 24, 2017 6:36 AM
To: dev@hawq.incubator.apache.org
Subject: s/gettimeofday/clock_gettime/ in hawq?

Hi,

HAWQ sometimes use gettimeofday() syscall for some timeout check in various
module, however it could be affected by ntp, so the timeout checking logic
could be wrong sometimes. I would propose to use clock_gettime() to replace
it on Linux (I have not investigated the alternative on other platforms
e.g. mac). Both gettimeofday() and clock_gettime() are fast vdso sys call
so I do not expect there is performance loss in some case where there are
frequent calls of gettimeofday(). By the way, I found some gettimeofday()
calls on postgresql and gpdb, so they might have this issue also.

Regards,

Paul
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