Re: now() does not change within a transaction

On Thu, Apr 18, 2002 at 02:04:35PM +0000, Christoph Haller wrote:
> Hi pgsql-sql list,
> I did some testing around tables using a column
> timestamp with time zone not null default now().
> I have noticed a valuable feature:
> As long as being inside a transaction initiated by
> begin;
> the return value of the now() function does not change.
> Is this intended - as written in the documentation?

Sure. See (for example):

http://docs.linux.cz/PostgreSQL/functions-datetime.html#FUNCTIONS-DATETIME-CURRENT

It is quite important to realize that CURRENT_TIMESTAMP and related
functions all return the time as of the start of the current transaction;
their values do not increment while a transaction is running. But
timeofday() returns the actual current time.

test=# select timeofday()::timestamp;
timeofday
-------------------------------
2002-04-18 14:39:36.459162+02

Karel

--
Karel Zak <zakkr(at)zf(dot)jcu(dot)cz>
http://home.zf.jcu.cz/~zakkr/

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