Re: Additional current timestamp values - Mailing list pgsql-patches

From Neil Conway
Subject Re: Additional current timestamp values
Date
Msg-id 441F3729.5060109@samurai.com
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In response to Re: Additional current timestamp values  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: Additional current timestamp values  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-patches
Bruce Momjian wrote:
> Peter Eisentraut wrote:
>> The most common complaint that I recall is that current_timestamp
>> returns the transaction timestamp rather than the statement timestamp,
>> which is what many expect.  How does your patch address that?
>
> No, we believe the standard requires it.

My copy of SQL 200n has the following to say:

Annex C, paragraph 16:

     "The time of evaluation of the CURRENT_DATE, CURRENT_TIME, and
     CURRENT_TIMESTAMP functions during the execution of an
     SQL-statement is implementation-dependent."

6.31, <datetime value function>:

     (1) The <datetime value function>s CURRENT_DATE, CURRENT_TIME,
     and CURRENT_TIMESTAMP respectively return the current date,
     current time, and current timestamp; the time and timestamp values
     are returned with time zone displacement equal to the current
     default time zone displacement of the SQL-session. [...]

     (2) Let S be an <SQL procedure statement> that is not generally
     contained in a <triggered action>. All <datetime value function>s
     that are contained in <value expression>s that are generally
     contained, without an intervening <routine invocation> whose subject
     routines do not include an SQL function, either in S without an
     intervening <SQL procedure statement> or in an <SQL procedure
     statement> contained in the <triggered action> of a trigger
     activated as a consequence of executing S, are effectively evaluated
     simultaneously. The time of evaluation of a <datetime value
     function> during the execution of S and its activated triggers is
     implementation-dependent.

-Neil


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