Re: 9.5 release notes - Mailing list pgsql-hackers

From David Rowley
Subject Re: 9.5 release notes
Date
Msg-id CAKJS1f9LQ_AT7XFwt3JXgx0iquo=_nt2J=pEir_MZ9Yo2aJ8fg@mail.gmail.com
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In response to Re: 9.5 release notes  (Bruce Momjian <bruce@momjian.us>)
Responses Re: 9.5 release notes
List pgsql-hackers

On 7 August 2015 at 14:24, Bruce Momjian <bruce@momjian.us> wrote:
On Tue, Jun 30, 2015 at 09:00:44PM +0200, Andres Freund wrote:
> * 2014-12-08 [519b075] Simon ..: Use GetSystemTimeAsFileTime directly in win32
>   2014-12-08 [8001fe6] Simon ..: Windows: use GetSystemTimePreciseAsFileTime if ..
>   Timer resolution isn't a unimportant thing for people using explain?

This all seemed very internals-only, e.g.:

    On most Windows systems this change will actually have no significant effect on
    timestamp resolution as the system timer tick is typically between 1ms and 15ms
    depending on what timer resolution currently running applications have
    requested. You can check this with clockres.exe from sysinternals. Despite the
    platform limiation this change still permits capture of finer timestamps where
    the system is capable of producing them and it gets rid of an unnecessary
    syscall.

Was I wrong?


This does have a user visible change. Timestamps are now likely to have 6 digits after the decimal point, if they're on a version of windows which supports GetSystemTimePreciseAsFileTime();

Master:

postgres=# select now();
              now
-------------------------------
 2015-08-09 01:14:01.959645+12
(1 row)

9.4.4
postgres=# select now();
            now
----------------------------
 2015-08-09 01:15:09.783+12
(1 row)

Regards

David Rowley

--
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services
 

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