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From: "Marshall" <marshall.spight@gmail.com>
Newsgroups: comp.databases.theory
Subject: Re: Navigation question
Date: 16 Feb 2007 17:19:37 -0800
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On Feb 16, 3:04 pm, "Tony D" <tonyisyour...@netscape.net> wrote:
> On Feb 16, 8:08 pm, "dawn" <dawnwolth...@gmail.com> wrote:
>
> > I think Marshall is telling me that both of his queries could
> > together go to the DBMS at the same time and the DBMS might execute
> > them together in some different order.
>
> That would be quite an optimisation, and I don't know of a DBMS that
> does that. References, anyone ?

'Tis a theory newsgroup. It's enough that the optimization I describe
be implementable; it doesn't need to be actually implemented.

I wrote an ODBC driver circa 1995 that would do API coalescing
and reordering to minimize network roundtrips. It couldn't do the
optimization specifically on those two queries; ODBC provides
few opportunities for such reordering. However one could imagine,
say, an asynchronous JDBC tag library that would permit this
optimization.


Marshall