Re: start of transaction (was: Re: [PERFORM] Help with count(*)) - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: start of transaction (was: Re: [PERFORM] Help with count(*))
Date
Msg-id 200311180052.hAI0qpw10716@candle.pha.pa.us
Whole thread Raw
In response to Re: start of transaction (was: Re: [PERFORM] Help with  (Hannu Krosing <hannu@tm.ee>)
Responses Re: start of transaction (was: Re: [PERFORM] Help with count(*))  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hannu Krosing wrote:
> Bruce Momjian kirjutas E, 17.11.2003 kell 02:31:
> 
> > Defining now() as the first call seems pretty arbitrary to me.  I can't
> > think of any time-based interface that has that API.  And what if a
> > trigger called now() in an earlier query and you didn't even know about
> > it.
> 
> That would be OK. The whole point of that previous discussion was to
> have now() that returns the same value over the span of the whole
> transaction.

I think my issue is that there isn't any predictable way for a user to
know when the now() time is recorded.  By using start of transaction, at
least we know for sure the point in time it is showing.

> It would be even better to have now() that returns the time current
> transaction is COMMITted as this is the time other backend become aware
> of it ;)

True, but implementing that would be very hard.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


pgsql-hackers by date:

Previous
From: "Marc G. Fournier"
Date:
Subject: Re: Release cycle length
Next
From: Bruce Momjian
Date:
Subject: Re: Release now live ...