[Info-vax] Oracle on VMS

[Jan-Erik Soderholm]

Den 2016-11-20 kl. 07:01, skrev IanD:
> Embedded or Modular ?
>
> Modular separates the SQL component from the language, technically
> meaning you can change languages and not touch the DB side (yeah
> right!!!)
>
> Modular came after embedded and was supposed to be the natural evolution
> on from embedded but there is so much embedded RDB code around that I
> think people who maintained RDB just stuck with embedded versus learning
> another paradigm and/or converting
>
> I think there were some differences around error returns with modular
> being more comprehensive? but I'm trying to remember from 10 years ago
> and I really only did fairly simplistic stuff with it

We have a mix. Someone long ago thought modular language was the thing
so there are a couple of large .SQLMOD files compiled to OBJ. Each
having up to 50 or so different SQL functions. But any new development
is done using embedded SQL. No problem mixing than in the same source
file, of course.


>
> Yes, modern DB's do cache execution plans, RDB I believe was the first
> to come up with the idea of a query optimizer and unlike MySQL (or how
> it used to be) with RDB you can access the query optimiser for free and
> it's cincluded in the price and even make changes to it to force your
> own behavior if you believe the DB got it wrong on it's strategy
> (usually happens when it gets the number of tuples wrong on complex
> joins etc)
>
> I wonder with the push for dynamic languages how much optimisation is
> worth it at compile time versus having a smarter optimiser at run time?

With dynamic SQL (where the SQL is sent in plain text to the DB each time)
the DB has to do syntaxt check each time an SQL is executed. So there is
some overhead. It's like olny using the SQL> interactive prompt in Rdb.

> I guess some information could be supplied to the DB in advance because
> RDB creates a strategy at run time and formulates it's strategy then -
> being forewarned wth inside knowledge from an EXE might help?
>
> This sort of stuff is way beyond my knowledge base. I used to have
> enough fun and games just tuning RDB and playing with optimiser
> strategies yet along designing an optimising engine beast !
>