Thread: AW: Performance (was: The New Slashdot Setup (includes MySqlserver))

> > > 3. automatic_rowid = no
> > > 
> > > The description simply says Automatic rowid. Does this apply to
> > > query result sets or to the underlying relation? If the latter,
> > > PostgreSQL has, of course, an OID for every tuple in the
> > > database.
> > > 
> > I'll have them fix that. MySQL calls them "_rowid" and 
> apparently tests
> > only for these.
> 
> Well, I don't see _rowid in the SQL spec either, so we are both
> non-standard here, though I believe our OID is SQL3.

Which is imho not what the test is for. I think they mean ctid,
which again I think we should have a rowid alias for (as in Informix,
Oracle).

Andreas

Zeugswetter Andreas SB writes:

> Which is imho not what the test is for. I think they mean ctid,
> which again I think we should have a rowid alias for (as in Informix,
> Oracle).

Let's step back and ask: How is the behaviour of rowid (or whatever)
defined in various existing DBMS. Then we can see if we have anything that
matches.

-- 
Peter Eisentraut                  Sernanders väg 10:115
peter_e@gmx.net                   75262 Uppsala
http://yi.org/peter-e/            Sweden

On Fri, 26 May 2000, Peter Eisentraut wrote:
> Zeugswetter Andreas SB writes:
> 
> > Which is imho not what the test is for. I think they mean ctid,
> > which again I think we should have a rowid alias for (as in Informix,
> > Oracle).
> 
> Let's step back and ask: How is the behaviour of rowid (or whatever)
> defined in various existing DBMS. Then we can see if we have anything that
> matches.

This has been discussed. The outcome is, that you are only safe using rowid
if nobody else changes the row inbetween you reading it and accessing it by rowid.

This is essentially the same in all db's only the risk of rowid changing is lower
in other db's since they do inplace update, but the risk is there nevertheless.

Andreas