Re: [BUGS] BUG #14838: clock_timestamp() returns same values for each row - Mailing list pgsql-bugs

From Jeff Janes
Subject Re: [BUGS] BUG #14838: clock_timestamp() returns same values for each row
Date
Msg-id CAMkU=1wBg8EL3YdeW1tAciCYyFTVBBsYdqznRHG2U1=W4mFXjg@mail.gmail.com
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In response to [BUGS] BUG #14838: clock_timestamp() returns same values for each row  (zam6ak@gmail.com)
Responses Re: [BUGS] BUG #14838: clock_timestamp() returns same values for each row
List pgsql-bugs
On Fri, Sep 29, 2017 at 6:43 AM, <zam6ak@gmail.com> wrote:
The following bug has been logged on the website:

Bug reference:      14838
Logged by:          zam zam
Email address:      zam6ak@gmail.com
PostgreSQL version: 10rc1
Operating system:   Windows 10
Description:

Hello

We use clock_timestamp() function in our code and I have noticed that in PG
10 RC1 it returns same values across rows...

Here is the output from 9.6 compare to 10rc1

select version();
-- "PostgreSQL 9.6.3, compiled by Visual C++ build 1800, 64-bit"

-- "PostgreSQL 10rc1 on x86_64-pc-mingw64, compiled by gcc.exe (Rev5, Built
by MSYS2 project) 4.9.2, 64-bit"


Probably not an issue of the different versions, but rather different compilers (or maybe different hardware?).

I get the same behavior on these two versions:

PostgreSQL 9.6.5, compiled by Visual C++ build 1800, 64-bit
PostgreSQL 10rc1, compiled by Visual C++ build 1800, 64-bit

and that behavior is that the timestamp jumps 500 usec at a time, despite looking as if it might have usec granularity:



 2017-09-29 10:34:50.881312-07
 2017-09-29 10:34:50.881312-07
 2017-09-29 10:34:50.881312-07
 2017-09-29 10:34:50.881312-07
 2017-09-29 10:34:50.881312-07
 2017-09-29 10:34:50.881812-07  <-- see here and above
 2017-09-29 10:34:50.881812-07
 2017-09-29 10:34:50.881812-07
 2017-09-29 10:34:50.881812-07

You probably don't see the jump in your 2nd example because you didn't run enough rows to cross a 500 usec boundary.

Cheers,

Jeff

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