Re: values from now() in the same transaction

zelvlad(at)yahoo(dot)com (Vladimir Zelinski) writes:
> I tried function now(),current_timestamp() but all of
> them behave similar.
>
> I don't believe that it's bug, probably it's a feature
> of the postgreSql database.

Indeed, that is intentional. CURRENT_TIMESTAMP and NOW() return the
time at which the transaction began.

> Is any way to insert a timestamp within the same transaction that
> would have current system time (not time of the beginning of the
> transaction)?

> With other words, I would like to see different timestamps on first
> and last timestamp.

timeofday() is what you are looking for.

Consider the following series of queries; they demonstrate how the
behaviours of now() and timeofday() differ fairly successfully...

oxrsorg=# begin;
BEGIN
oxrsorg=# select now();
now
-------------------------------
2007-02-16 23:23:23.094817+00
(1 row)

oxrsorg=# select timeofday();
timeofday
-------------------------------------
Fri Feb 16 23:23:31.481780 2007 UTC
(1 row)

oxrsorg=# select timeofday();
timeofday
-------------------------------------
Fri Feb 16 23:23:32.981137 2007 UTC
(1 row)

oxrsorg=# select timeofday();
timeofday
-------------------------------------
Fri Feb 16 23:23:33.988252 2007 UTC
(1 row)

oxrsorg=# select now();
now
-------------------------------
2007-02-16 23:23:23.094817+00
(1 row)

oxrsorg=# select timeofday();
timeofday
-------------------------------------
Fri Feb 16 23:23:38.643998 2007 UTC
(1 row)

oxrsorg=# select now();
now
-------------------------------
2007-02-16 23:23:23.094817+00
(1 row)

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