And even an addendum to this question: Is there (I read something 'akin' to this in the mailing archive) a big performance hit as well?
I like to use beans/shadow facts for a variety of reasons, but have always been under the impression that when i'm going to assert a 'huge' number of a particular fact type, that I should be using a deftemplate/fact API versus just using defclass/definstance of a bean representing the exact same information. Thanks, Roger On 11/22/05, Scott Moss <[EMAIL PROTECTED]> wrote: > > It would be useful to me to extend this discussion a little-- > specifically to the memory requirements of facts and shadow facts. Is > there any way of know whether a shadow fact relating to a Java object > with (say) all fields having getter and setter methods (the latter > having property change support) uses more or less memory than a Fact > with the same number and types of slots? The question is about relative > rather than absolute memory usage. > > thanks. > > [EMAIL PROTECTED] wrote: > > >I think Kristina Marasovic wrote: > >[Charset iso-8859-1 unsupported, filtering to ASCII...] > > > > > >>Hi, > >> > >>can someone tell me if it is possible (and how) to get or to measure the > >>size of an activation record. > >> > >> > > > >You don't really know the size of *any* Java object, as the details of > >object representation are implementation-dependent. Furthermore, it's > >rather tricky to determine "the size of an object" when that object is > >part of a dense interconnected web of objects like Jess's Rete > >network. > > > >That said, in the current implementation, an Activation object has 4 > >members, which at 4 bytes each is 16 bytes. Along with the > >generally-assumed Java memory overhead per object of 16 bytes, that > >means each Activation is 32 bytes. If you have 756,000 of them, that's > >24 MB. If you include the 4 byte array element that holds each > >Activation, then that adds another 3 MB. > > > >Now, each Activation record has a reference to a Defrule (which would > >exist anyway) and a Token in the Rete network. If you want to start > >including those Tokens in the memory count, then it becomes very > >complicated very quickly, as many, many Tokens are shared, and also > >Token is a recursive data structure -- a Token usually contains a > >reference to another "parent" token. The depth of the recursion and > >the amount of sharing is entirely dependent on the nature of your > >rules. > > > > > > > > > >--------------------------------------------------------- > >Ernest Friedman-Hill > >Advanced Software Research Phone: (925) 294-2154 > >Sandia National Labs FAX: (925) 294-2234 > >PO Box 969, MS 9012 [EMAIL PROTECTED] > >Livermore, CA 94550 http://herzberg.ca.sandia.gov > > > >-------------------------------------------------------------------- > >To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' > >in the BODY of a message to [EMAIL PROTECTED], NOT to the list > >(use your own address!) List problems? Notify [EMAIL PROTECTED] > . > >-------------------------------------------------------------------- > > > > > > -- > Professor Scott Moss > Director > Centre for Policy Modelling > Manchester Metropolitan University > Aytoun Building > Manchester M1 3GH > > http://cfpm.org/~scott > > (t) +44 (0)161 247 3886 > (f) +44 (0)161 247 6802 > (m) +44 (0)7740 942564 > > -------------------------------------------------------------------- > To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' > in the BODY of a message to [EMAIL PROTECTED], NOT to the list > (use your own address!) List problems? Notify [EMAIL PROTECTED]
