Correction (missing single quotes): (format t "~8,'0X ~8,0'X" slot-a-val slot-b-val)
On Wed, Jan 14, 2009 at 12:07 PM, Yarek Kowalik <yarek.kowa...@gmail.com>wrote: > Out of curiosity, the OIDs in elephant are they 32 bit integers or 64? I'm > running on Ubuntu-64/SBCL-64. > > I'm thinking that my 'query' slot vale would be generated something like > this (for 32 bit values): > > (format t "~8,0X ~8,0X" slot-a-val slot-b-val) > > Yarek > > > On Tue, Jan 13, 2009 at 5:51 PM, Robert Synnott <rsynn...@gmail.com>wrote: > >> I don't believe the Postmodern backend, at least, allows search by conses. >> >> If you want sensible (ordered) results with a and b if a and/or b are >> integers, by the way, you should zero-pad them; otherwise, say, '1 2' >> comes after '1 12', which is probably not what you want >> Rob >> >> 2009/1/14 Yarek Kowalik <yarek.kowa...@gmail.com>: >> > When serializing tuples, is the string representation best: You suggest >> > using (format t "~A ~A" a b) - is that efficient enough? what about >> doing >> > (cons a b) = is there a way to index and search for conses? Any other >> ideas? >> > >> > Yarek >> > >> > On Tue, Jan 6, 2009 at 5:17 AM, Alex Mizrahi <killerst...@newmail.ru> >> wrote: >> >> >> >> YK> Is this a reasonable way of finding an object of type >> >> YK> 'my-class that matches on values val-a and val-b for slots a and b? >> >> >> >> yep, it is reasonable if you have relatively low number of objects >> >> in returned by (get-instances-by-value 'my-class 'slot-b val-b) query. >> >> if number of objects is significant and you get a slowdown because >> >> of this, you might want to optimize this. a trivial thing is to try it >> >> symmertrically with slot-a -- whatever returns less objects is better. >> >> less trivial optimizations would be to work on lower-level -- via >> >> map-inverted-index (to avoid allocating whole list but instead test >> >> objects >> >> one by one) or even cursor API (this way you can retrieve oids rather >> >> than objects, which should be faster, and also iterating both indices >> at >> >> once might be a significant benefit if values are not uniformly >> >> distributed). >> >> >> >> but the most optimal way doing this in case of high number of objects >> >> in both slot-a and slot-b queries would be building and using >> multi-column >> >> index. unfortunately, Elephant does not help you with it -- either >> you'll >> >> have >> >> to serialize slot tuples into a string (e.g (format nil "~a_~a" slot-a >> >> slot-b)), >> >> or reorganize your data to use a custom index structure (like btree of >> >> btrees). >> >> >> >> there are also backend-specific considerations. for postmodern >> >> >> >> (intersection (get-instances-by-value 'my-class 'slot-b val-b) >> >> (get-instances-by-value 'my-class 'slot-a val-a)) >> >> >> >> would be much faster then testing objects one by one, for BDB -- i >> doubt >> >> so. >> >> >> >> LP> Use MAP-CLASS, this will considerably speed up the query. >> >> >> >> how is that? using at least one index is much better than using no >> index >> >> at >> >> all. >> >> >> >> >> >> >> >> >> >> _______________________________________________ >> >> elephant-devel site list >> >> elephant-devel@common-lisp.net >> >> http://common-lisp.net/mailman/listinfo/elephant-devel >> > >> > >> > _______________________________________________ >> > elephant-devel site list >> > elephant-devel@common-lisp.net >> > http://common-lisp.net/mailman/listinfo/elephant-devel >> > >> >> >> >> -- >> Robert Synnott >> http://myblog.rsynnott.com >> MSN: rsynn...@gmail.com >> Jabber: rsynn...@gmail.com >> >> _______________________________________________ >> elephant-devel site list >> elephant-devel@common-lisp.net >> http://common-lisp.net/mailman/listinfo/elephant-devel >> > >
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