[Monetdb-developers] join performance issue!
Stefan.Manegold at cwi.nl
Tue Jul 25 22:24:16 CEST 2006
On Tue, Jul 25, 2006 at 10:02:16PM +0200, Arjen P. de Vries wrote:
> Wasn't the property checking always determined by debug flag 8?
in general: yes.
for join: no, at least not any more since the following checkin:
2003/08/06 - sjoerd: src/gdk/gdk_relop.mx,1.38
This is the big one!
Before tag: BeforeDDImerge, after tag: AfterDDImerge.
The DDI merge is now made the official main branch; the CWI_DDI_merge branch
is not to be used anymore.
Well, Sjoerd just did the checking; the origin is most probabaly Peter.
As I said, there are indeed good reasons to do the BATpropcheck (even with
debug=0) for *arbitrary* joins, where we can hardly predict any result
properties --- maybe, we should consider to not do it in those cases
(especially fetchjoin), where we can predict the join result properties
> On 25/07/06, Martin Kersten <Martin.Kersten at cwi.nl> wrote:
> >Stefan Manegold wrote:
> >> Dear all,
> >> - We should consider making this BATpropcheck in BATjoin and BATleftjoin
> >> configurable from the outside, e.g., by adding an extra optional
> >> to join() to request to skipping the BATpropcheck.
> >Instead of pollution of the calling interface, I think we should inject
> >an explicit request to check/enforce properties. This one might also be
> >focussed on those properties of interest according to the optimizer at
> >that point.
> >In M5:
> > b:= algebra.join(BAT,BAT);
> > bat.setProperties(b);
> > ...
> > bat.checkDenseProperty(b);
> > bat.checkOrderProperty(b);
> > bat.checkKeyProperty(b);
> >But first, assess the use of the join(bat,bat) in our controlled
> >code base. Please report on this.
> >regards, Martin
> CWI, room C1.16 Centre for Mathematics and Computer Science
> Kruislaan 413 Email: Arjen.de.Vries at cwi.nl
> 1098 SJ Amsterdam tel: +31-(0)20-5924306
> The Netherlands fax: +31-(0)20-5924312
> ===================== http://www.cwi.nl/~arjen/ ====================
| Dr. Stefan Manegold | mailto:Stefan.Manegold at cwi.nl |
| CWI, P.O.Box 94079 | http://www.cwi.nl/~manegold/ |
| 1090 GB Amsterdam | Tel.: +31 (20) 592-4212 |
| The Netherlands | Fax : +31 (20) 592-4312 |
More information about the developers-list