What are you specifying for your sort criteria? And what kind of field is it we're talking about here?
Best Erick On Tue, Dec 20, 2011 at 8:45 AM, Qiurun <qiu...@huawei.com> wrote: > Dear all, > > I select some of docs that meet some criteria by using TopDocs search(Query > query, int n). Also It's easy to select the docs that meet some query and > sort by some field by using TopFieldDocs search(Query query, int n, Sort > sort). As known, Lucene use field cache when sorting results by field values. > According to Lucene in action (second editon), "The first time the field > cache is accessed for a given reader and field, the values for all documents > are visited and loaded into memory as a single large array, and recorded into > an internal cache keyed on the reader instance and the field name. This > process can be quite time consuming, for a large index.", "FieldCache does > not clear its entries until you close your reader and remove all references > to that reader from your application." > > Now we have an index with about 200 millions docs in it. However, we can not > find the obvious performance difference between the two ways. And I want to > know why, thanks for your advice. > > (We are using Lucene 3.2.0 and java version 1.6.0_26 on SuSe Linux Enterprise > Server 10 sp2.) > > Best, > Qiu Run > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
