Re: [GENERAL] CURRENT_TIMESTAMP - Mailing list pgsql-sql

From Bruce Momjian
Subject Re: [GENERAL] CURRENT_TIMESTAMP
Date
Msg-id 200209232041.g8NKfix19001@candle.pha.pa.us
Whole thread Raw
In response to Re: [GENERAL] CURRENT_TIMESTAMP  (Josh Berkus <josh@agliodbs.com>)
Responses Re: [GENERAL] CURRENT_TIMESTAMP  (Josh Berkus <josh@agliodbs.com>)
Re: [GENERAL] CURRENT_TIMESTAMP  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-sql
Josh Berkus wrote:
> I, for one, would judge that the start time of the statement is "during the 
> execution"; it would only NOT be "during the execution" if it was a value 
> *before* the start time of the statement.  It's a semantic argument.
> 
> The spec is, IMHO, rather vague on how this would relate to transactions.  I 
> do not find it at all inconsitent that Bruce, Thomas, and co. interpreted a 
> transaction to be an extension of an individual SQL statement for this 
> purpose (at least, that's what I guess they did).
> 
> Thus, if you accept the postulates that:
> 1) "During" a SQL statement includes the start time of the statement, and
> 2) A Transaction is the equivalent of a single SQL statement for many 
> purposes, 
> Then the current behavior is a logical conclusion.
> 
> Further, we could not change that behaviour without breaking many people's 
> applications.

I don't see how we can defend returning the start of the transaction as
the current_timestamp.  In a multi-statement transaction, that doesn't
seem very current to me.  I know there are some advantages to returning
the same value for all queries in a transaction, but is that value worth
returning such stale time information?

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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