[MonetDB-users] Profiling queries

Niels Nes Niels.Nes at cwi.nl
Wed Dec 5 09:15:54 CET 2007

On Wed, Dec 05, 2007 at 01:06:07AM -0700, m h wrote:
> > But your old db is block oriented. And your data is somehow organised
> > that that doesn't hurt much too (any sorting or cluster indices?).
> There are indexes on all the columns in the WHERE clause

> > > Primary and unique yes, no foreign.
> > No foreign make the joins expensive afcourse, are these single column
> > joins are are these joins over multiple columns?
> So an optimization is to remove all foreign keys?  I'll need to double
> check if there are FK's after sleep....  Obviously most entries in the
> FACT table could be FKs.
No the other way arround. Having foreign keys will give you 'join-indices'
ie the joins should be (almost) for free.



Niels Nes, Centre for Mathematics and Computer Science (CWI)
Kruislaan 413, 1098 SJ Amsterdam, The Netherlands
room C0.02,  phone ++31 20 592-4098, fax ++31 20 592-4312
url: http://www.cwi.nl/~niels   e-mail: Niels.Nes at cwi.nl

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