Stephane,

> > It is logical for me, since before inserting, it needs to know if
> > similar record already exists (to be update). Sso, more operations are
> > being done (more disk I/O) compared to a single insert.
> >
>
> i was thinging than during an update or insert, the engine try first to "insert
> the record" ... and if no error then OK (so exactly like an
> insert) and
> if an error then at this time try to update the record (and the engine already
> know with page to update thank to the previous failed update)

If the command was "INSERT OR UPDATE" instead of "UPDATE OR INSERT" you would be correct.


Sean