It's academic. Set timing on in psql and run a bunch of tests. The variation
from test to test is large enough to mask any difference between select 0 or
select '' or select null.
It would, however, be nice to know the reason for this query. I suspect it is
to "ping" the server and making sure it is up by connecting and running a
simple query with a known result. (Many colos have all sorts of setups for
monitoring web servers but fewer for other services - setting up a "test"
page on the web server that makes a request from the app server which, in
turn, does a simple db query, all of which ultimately returns a standard
string, say "system up", to the http request works quite well to set off
alarm bells at the colo or even to allow a load balancer to take action).
But I am surmising. What is the real reason for the query?
Cheers,
Steve
On Thursday 20 February 2003 11:52 am, Jonathan Bartlett wrote:
> Might select NULL; be faster, since the number doesn't have to be parsed,
> and null is probably a keyword?
>
> Jon
>
> On Thu, 20 Feb 2003, Tino Wildenhain wrote:
> > Hi P G,
> >
> > On Thu, 20 Feb 2003 09:52:07 -0800 (PST)
> >
> > P G <pg_dba@yahoo.com> wrote:
> > > What is the quickest and least intrusive query in the
> > > database that will always succeed?
> >
> > select 1;
> >
> > :o)
> >
> > Regards
> > Tino
> >
> > > select current_user;
> > >
> > > -- OR --
> > >
> > > select datname from pg_database where datname =
> > > 'some_database';
> > >
> > > Or would it be something else?
> > >
> > > TIA.
> > >
> > > __________________________________________________
> > > Do you Yahoo!?
> > > Yahoo! Tax Center - forms, calculators, tips, more
> > > http://taxes.yahoo.com/
> > >
> > > ---------------------------(end of
> > > broadcast)--------------------------- TIP 3: if posting/reading through
> > > Usenet, please send an appropriate subscribe-nomail command to
> > > majordomo@postgresql.org so that your message can get through to the
> > > mailing list cleanly
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 5: Have you checked our extensive FAQ?
> >
> > http://www.postgresql.org/users-lounge/docs/faq.html
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly
