Don, I think I finally understand your problem -- and mine -- with MultiSearcher. I had tested an implementation of my system using ParallelMultiSearcher to split a huge index over many computers. I was very impressed by the results on my test data, but alarmed after a trial with live data :)
Consider MultiSearcher.search(Query Q). Suppose that Q aggregated over ALL the Searchables in the MultiSearcher would return 1000 documents. But, the Hits object created by search() will only cache the first 100 documents. When Hits.doc(101) is called, Hits will cache 200 documents -- then 400, 800, 1600 and so on. How does Hits get these extra documents? By calling the MultiSearcher again. Now consider a MultiSearcher as described above with 2 Searchables. With respect to Q, Searchable S has 1000 documents, Searchable T has zero. So to fetch the 101st document, not only is S searched, but T is too, even though the result of Q applied to T is still zero and will always be zero. The same thing will happen when fetching the 201st, 401st and 801st document. This accounts for my slow performance, and I think yours too. That your observed degradation is a power of 2 is a clue. My performance is especially vulnerable because "slave" Searchables in the MultiSearcher are Remote -- accessed via RMI. I guess I have to code smarter around MultiSearcher. One problem you highlight is that Hits is final -- so it is not possible even to modify the "100/200/400" cache size logic. Any ideas from anyone would be much appreciated. Mark Florence CTO, AIRS 800-897-7714 x 1703 [EMAIL PROTECTED] -----Original Message----- From: Don Vaillancourt [mailto:[EMAIL PROTECTED] Sent: Monday, July 12, 2004 12:36 pm To: Lucene Users List Subject: Anyone use MultiSearcher class Hello, Has anyone used the Multisearcher class? I have noticed that searching two indexes using this MultiSearcher class takes 8 times longer than searching only one index. I could understand if it took 3 to 4 times longer to search due to sorting the two search results and stuff, but why 8 times longer. Is there some optimization that can be done to hasten the search? Or should I just write my own MultiSearcher. The problem though is that there is no way for me to create my own Hits object (no methods are available and the class is final). Anyone have any clue? Thanks Don Vaillancourt Director of Software Development WEB IMPACT INC. 416-815-2000 ext. 245 email: [EMAIL PROTECTED] web: http://www.web-impact.com This email message is intended only for the addressee(s) and contains information that may be confidential and/or copyright. If you are not the intended recipient please notify the sender by reply email and immediately delete this email. Use, disclosure or reproduction of this email by anyone other than the intended recipient(s) is strictly prohibited. No representation is made that this email or any attachments are free of viruses. Virus scanning is recommended and is the responsibility of the recipient. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
