Re: What is the quickest query in the database? - Mailing list pgsql-general

But, unless there is a timeout on that query, wont the system being down
really hang you up, until your script reaches it's default timeout?

We had this problem with PHP and Perl in the past. Is there a way to get
around this in Java?

- Ericson Smith
eric@did-it.com

On Thu, 2003-02-20 at 15:32, P G wrote:
> You are correct Steve Crawford.  The query is used to
> remotely test the connection to the db using JDBC.  I
> think, though, Jan Wieck provides the most valuable
> solution so far.  Any more thoughts, anyone?
>
> TIA.
>
> --- Steve Crawford <scrawford@pinpointresearch.com>
> wrote:
> > 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.
> > > > >
> > > > >
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--
Ericson Smith <eric@did-it.com>