Обсуждение: now() gives same time within the session
Hi,
I need to log the start and end time of the procedures in a table. But the start and end time are same. This is how I recreated the issue.
create table test_time (time timestamp);
delete from test_time;
insert into test_time select now();
SELECT pg_sleep(10);
insert into test_time select now();
SELECT pg_sleep(10);
insert into test_time select now();
SELECT pg_sleep(10);
insert into test_time select now();
SELECT pg_sleep(10);
select * from test_time;
"2010-07-12 12:43:40.509746"
"2010-07-12 12:43:40.509746"
"2010-07-12 12:43:40.509746"
"2010-07-12 12:43:40.509746"
Atul Goel
SENIOR DEVELOPER
Global DataPoint
Middlesex House, 34-42 Cleveland Street
London W1T 4LB, UK
T: +44 (0)20 7079 4827
M: +44 (0)7846765098
In response to Atul.Goel@globaldatapoint.com :
> Hi,
>
>
>
> I need to log the start and end time of the procedures in a table. But the
> start and end time are same. This is how I recreated the issue.
>
>
>
> create table test_time (time timestamp);
>
> delete from test_time;
>
> insert into test_time select now();
Use timeofday() instead, now() returns the transaction starting time.
BEGIN
test=*# select now();
now
-------------------------------
2010-07-12 13:13:28.907043+02
(1 row)
test=*# select timeofday();
timeofday
--------------------------------------
Mon Jul 12 13:13:36.187703 2010 CEST
(1 row)
test=*# select now();
now
-------------------------------
2010-07-12 13:13:28.907043+02
(1 row)
test=*#
Regards, Andreas
--
Andreas Kretschmer
Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header)
GnuPG: 0x31720C99, 1006 CCB4 A326 1D42 6431 2EB0 389D 1DC2 3172 0C99
Sure thanks a lot.
Regards,
Atul Goel
-----Original Message-----
From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of A. Kretschmer
Sent: 12 July 2010 12:15
To: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] now() gives same time within the session
In response to Atul.Goel@globaldatapoint.com :
> Hi,
>
>
>
> I need to log the start and end time of the procedures in a table. But the
> start and end time are same. This is how I recreated the issue.
>
>
>
> create table test_time (time timestamp);
>
> delete from test_time;
>
> insert into test_time select now();
Use timeofday() instead, now() returns the transaction starting time.
BEGIN
test=*# select now();
now
-------------------------------
2010-07-12 13:13:28.907043+02
(1 row)
test=*# select timeofday();
timeofday
--------------------------------------
Mon Jul 12 13:13:36.187703 2010 CEST
(1 row)
test=*# select now();
now
-------------------------------
2010-07-12 13:13:28.907043+02
(1 row)
test=*#
Regards, Andreas
--
Andreas Kretschmer
Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header)
GnuPG: 0x31720C99, 1006 CCB4 A326 1D42 6431 2EB0 389D 1DC2 3172 0C99
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On Mon, Jul 12, 2010 at 4:15 AM, A. Kretschmer <andreas.kretschmer@schollglas.com> wrote: > In response to Atul.Goel@globaldatapoint.com : >> Hi, >> >> >> >> I need to log the start and end time of the procedures in a table. But the >> start and end time are same. This is how I recreated the issue. >> >> >> >> create table test_time (time timestamp); >> >> delete from test_time; >> >> insert into test_time select now(); > > > Use timeofday() instead, now() returns the transaction starting time. Is this part of the SQL standard? -- Rob Wultsch wultsch@gmail.com
On 12 July 2010 14:11, Rob Wultsch <wultsch@gmail.com> wrote: > On Mon, Jul 12, 2010 at 4:15 AM, A. Kretschmer > <andreas.kretschmer@schollglas.com> wrote: >> In response to Atul.Goel@globaldatapoint.com : >>> Hi, >>> >>> >>> >>> I need to log the start and end time of the procedures in a table. But the >>> start and end time are same. This is how I recreated the issue. >>> >>> >>> >>> create table test_time (time timestamp); >>> >>> delete from test_time; >>> >>> insert into test_time select now(); >> >> >> Use timeofday() instead, now() returns the transaction starting time. > > > Is this part of the SQL standard? > I don't believe it is. See http://www.postgresql.org/docs/current/static/functions-datetime.html#FUNCTIONS-DATETIME-CURRENT for more info. Thom
In response to Rob Wultsch : > On Mon, Jul 12, 2010 at 4:15 AM, A. Kretschmer > <andreas.kretschmer@schollglas.com> wrote: > > Use timeofday() instead, now() returns the transaction starting time. > > > Is this part of the SQL standard? Don't know, sorry. Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header) GnuPG: 0x31720C99, 1006 CCB4 A326 1D42 6431 2EB0 389D 1DC2 3172 0C99
On Mon, Jul 12, 2010 at 06:11:31AM -0700, Rob Wultsch wrote: > On Mon, Jul 12, 2010 at 4:15 AM, A. Kretschmer > <andreas.kretschmer@schollglas.com> wrote: > > In response to Atul.Goel@globaldatapoint.com : > >> Hi, > >> > >> > >> > >> I need to log the start and end time of the procedures in a table. But the > >> start and end time are same. This is how I recreated the issue. > >> > >> > >> > >> create table test_time (time timestamp); > >> > >> delete from ?test_time; > >> > >> insert into test_time select now(); > > > > > > Use timeofday() instead, now() returns the transaction starting time. > > > Is this part of the SQL standard? > No, see section 9.9.4 of the manual. Cheers, Ken
On 12/07/10 14:15, A. Kretschmer wrote: > Use timeofday() instead, now() returns the transaction starting time. timeofday() is a legacy function kept only for backwards-compatibility. It returns a string, which is quite awkward. Use clock_timestamp() instead. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com