Profile your application first hand and find out where the bottlenecks really are during indexing.
For me it was clearly the database calls which took most of the time. Due to a very complex SQL Query. I applied the Producer - Consumer pattern and put a blocking queue in between. I have a threadpool running x producers which are sending SQL Queries to the database. Each returned row is put into the blockingQueue and another threadpool running x (currently only 1) consumers is taking Objects from the row, converts them to lucene documents and adds them to the index. If the last row is put into the queue I add a Poison Pill to tell the consumer to break. Using a blockingQueue limited to 10.000 entries together with jdbc fetchSize avoids high memory consumptions if too many producer threads return from the db. This way I could reduce indexing time from around 8h to 30 min. (really). But be careful. Load on the DB Server will surely increase. Hope that helps. Cheers, Thomas Paul Taylor wrote: > I'm building a lucene index from a database, creating 1 about 1 million > documents, unsuprisingly this takes quite a long time. > I do this by sending a query to the db over a range of ids , (10,000) > records > Add these results in Lucene > Then get next 10,0000 and so on. > When completed indexing I then call optimize() > I also set indexWriter.setMaxBufferedDocs(1000) and > indexWriter.setMergeFactor(3000) but don't fully understand these values. > Each document contains about 10 small fields > > I'm looking for some ways to improve performance. > > This index writing is single threaded, is there a way I can multi-thread > writing to the indexing ? > I only call optimize() once at the end, is the best way to do it. > I'm going to run a profiler over the code, but are there any rules of > thumbs on the best values to set for MaxBufferedDocs and Mergefactor() > > thanks Paul > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > -- Thomas Becker Senior JEE Developer net mobile AG Zollhof 17 40221 Düsseldorf GERMANY Phone: +49 211 97020-195 Fax: +49 211 97020-949 Mobile: +49 173 5146567 (private) E-Mail: mailto:thomas.bec...@net-m.de Internet: http://www.net-m.de Registergericht: Amtsgericht Düsseldorf, HRB 48022 Vorstand: Theodor Niehues (Vorsitzender), Frank Hartmann, Kai Markus Kulas, Dieter Plassmann Vorsitzender des Aufsichtsrates: Dr. Michael Briem --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
