Re: Alternatives to SQL ... - Mailing list pgsql-general

The SQL interface is bullet-proof because it validates tables, computes
offsets, and stuff like that.  Passing something else into the database
and bypassing the SQL stage would require rewriting all the C logic for
SQL to match your new language --- a lot of work for little gain.

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Gunther Schadow wrote:
> Hi,
>
> I'm wondering about alternative accesses to a PostgreSQL data base
> by means other than SQL. I know one can map many things to SQL, but
> let me think outside the box for just a moment:
>
> - Sending a parse tree in XML for processing by the optimizer.
>    This circumvents the SQL language and avoids the kinds of
>    syntactic ideosyncrasies of SQL (e.g., where you put commas.)
>    This is fairly trivial, but of course the question is, would
>    it be worth it?
>
> - Sending an execution plan in XML directly to the executor.
>    This now circumvents the SQL parser and optimizer. I know this
>    in in a way against the relational doxology and I don't take that
>    light-heartedly. However, isn't it true that most optimizers
>    cannot deal very well with more than 6 joins? I may be wrong,
>    but I find myself spending quite a bit of time fighting with the
>    Oracle or PostgreSQL optimizer to convince it to choose the plan
>    that I want. There is so much magic to it with hints and the
>    way you write SQL (where in relational theory the expressions are
>    equivalent, they make huge difference in what plan is being
>    generated.) So, it appears to me almost easier to just send a
>    plan directly and have the system execute that plan.
>
> - These direct interfaces could be a nice way to experiment with
>    new strategies without having to implement it on all three
>    layers (SQL language, optimizer, and executor.)
>
> You noticed I sneaked in XML as the interface, and that would be
> neat because with XSLT it's so easy to manipulate. But I'm also
> thinking about a Prolog binding or constraint logic programming
> binding, that might be better optimizeable if it goes through a
> more direct path than SQL.
>
> Am I crazy?
> -Gunther
>
> --
> Gunther Schadow, M.D., Ph.D.                    gschadow@regenstrief.org
> Medical Information Scientist      Regenstrief Institute for Health Care
> Adjunct Assistant Professor        Indiana University School of Medicine
> tel:1(317)630-7960                         http://aurora.regenstrief.org
>
>
>
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