Hi all, I got one question: How does drools index the objects in memory? Does it use hashing index, based on what? Or drools uses adaptive indexing? Thanks a lot, Senlin

Senlin Liang wrote: One more question: does drools index intermediate results (such as the inserted objects in actions)? Any inserted object used in == constraints is indexed for that constraint. Is there any cost-based optimization for queries? no Thanks On Wed, Oct 15, 2008 at 9:10 AM, Senlin Liang <senlin.liang(a)gmail.com&gt; wrote: Hi all, I got one question: How does drools index the objects in memory? Does it use hashing index, based on what? Or drools uses adaptive indexing? Thanks a lot, Senlin _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

Senlin Liang wrote: Thanks Mark! I got another question: what kind of indexing is used in drools? what field does it index? It wil index the field used in the constraint Person( name == "mark" ) Person( name == $var ) Both of those pattners will be indexed no the name field, the first is what we call alpha node hashing, as it's on a literal and the latter is join node index on the name field. I checked the online manual, it seems that I uses hashing index, but i am not sure the details. The reason that I am asking this question is that: drools runs really faster for one of my program. In this program, there is information about DBLP publications: a(primary key, property, values), where primary key is the primary key of one publication, property can be one of "author, year, ...", and value is the value of the property. I run the query by joining the tables together using the primary key. Drools runs really fast for this program. I am wondering whether there is anything behind to make drools fast. Senlin On Wed, Oct 15, 2008 at 3:41 PM, Mark Proctor <mproctor(a)codehaus.org&gt; wrote: Senlin Liang wrote: One more question: does drools index intermediate results (such as the inserted objects in actions)? Any inserted object used in == constraints is indexed for that constraint. Is there any cost-based optimization for queries? no Thanks On Wed, Oct 15, 2008 at 9:10 AM, Senlin Liang <senlin.liang(a)gmail.com&gt; wrote: Hi all, I got one question: How does drools index the objects in memory? Does it use hashing index, based on what? Or drools uses adaptive indexing? Thanks a lot, Senlin _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

Senlin Liang wrote: My test query is result(Index, PaperName, Author, Year, Month) :- paper(Index, name, PaperName), paper(Index, author, Author), paper(Index, year, Year), paper(Index, month, Month). So drools builds alpha-hashing on the 2nd argument, and name-hashing on the 1st argument. Drools performs much more better than XSB/YAP for this query, and I am trying to figure out what is the reason behind. I don't know the implementation details for XSB or YAP, so not much more I can add other than what I've already said. Can't say it simpler than we hash literal constraints and index variable constraints. Mark Would you share some ideas? Thanks, Senlin On Wed, Oct 15, 2008 at 5:40 PM, Mark Proctor <mproctor(a)codehaus.org&gt; wrote: Senlin Liang wrote: Thanks Mark! I got another question: what kind of indexing is used in drools? what field does it index? It wil index the field used in the constraint Person( name == "mark" ) Person( name == $var ) Both of those pattners will be indexed no the name field, the first is what we call alpha node hashing, as it's on a literal and the latter is join node index on the name field. I checked the online manual, it seems that I uses hashing index, but i am not sure the details. The reason that I am asking this question is that: drools runs really faster for one of my program. In this program, there is information about DBLP publications: a(primary key, property, values), where primary key is the primary key of one publication, property can be one of "author, year, ...", and value is the value of the property. I run the query by joining the tables together using the primary key. Drools runs really fast for this program. I am wondering whether there is anything behind to make drools fast. Senlin On Wed, Oct 15, 2008 at 3:41 PM, Mark Proctor <mproctor(a)codehaus.org&gt; wrote: Senlin Liang wrote: One more question: does drools index intermediate results (such as the inserted objects in actions)? Any inserted object used in == constraints is indexed for that constraint. Is there any cost-based optimization for queries? no Thanks On Wed, Oct 15, 2008 at 9:10 AM, Senlin Liang <senlin.liang(a)gmail.com&gt; wrote: Hi all, I got one question: How does drools index the objects in memory? Does it use hashing index, based on what? Or drools uses adaptive indexing? Thanks a lot, Senlin _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users