What is the main difference between Hits and Collectors? - Mike aka...@gmail.com
On Mon, Nov 30, 2009 at 11:03 AM, Uwe Schindler <u...@thetaphi.de> wrote: > And if you only have a filter and apply it to all documents, make a > ConstantScoreQuery on top of the filter: > > Query q=new ConstantScoreQuery(cluCF); > > Then remove the filter from your search method call and only execute this > query. > > And if you iterate over all results never-ever use Hits! (its already > deprecated). Write a Collector instead (as you are not interested in > scoring). > > And: If you replace a relational database with Lucene, be sure not to think > in a relational sense with foreign keys / primary keys and so on. In > general > you should flatten everything. > > Uwe > > ----- > Uwe Schindler > H.-H.-Meier-Allee 63, D-28213 Bremen > http://www.thetaphi.de > eMail: u...@thetaphi.de > > > > -----Original Message----- > > From: Shai Erera [mailto:ser...@gmail.com] > > Sent: Monday, November 30, 2009 4:56 PM > > To: java-user@lucene.apache.org > > Subject: Re: Performance problems with Lucene 2.9 > > > > Hi > > > > First you can use MatchAllDocsQuery, which matches all documents. It will > > save a HUGE posting list (TAG:TAG), and performs much faster. For example > > TAG:TAG computes a score for each doc, even though you don't need it. > > MatchAllDocsQuery doesn't. > > > > Second, move away from Hits ! :) Use Collectors instead. > > > > If I understand the chain of filters, do you think you can code them with > > a > > BooleanQuery that is added BooleanClauses, each with is Term > > (field:value)? > > You can add clauses w/ OR, AND, NOT etc. > > > > Note that in Lucene 2.9, you can avoid scoring documents very easily, > > which > > is a performance win if you don't need scores (i.e. if you just want to > > match everything, not caring for scores). > > > > Shai > > > > On Mon, Nov 30, 2009 at 5:47 PM, Michel Nadeau <aka...@gmail.com> wrote: > > > > > Hi, > > > > > > we use Lucene to store around 300 millions of records. We use the index > > > both > > > for conventional searching, but also for all the system's data - we > > > replaced > > > MySQL with Lucene because it was simply not working at all with MySQL > > due > > > to > > > the amount or records. Our problem is that we have HUGE performance > > > problems... whenever we search, it takes forever to return results, and > > > Java > > > uses 100% CPU/RAM. > > > > > > Our index fields are like this: > > > > > > TYPE > > > PK > > > FOREIGN_PK > > > TAG > > > ...other information depending on type... > > > > > > * All fields are Field.Index.UN_TOKENIZED > > > * The field "TAG" always contains the value "TAG". > > > > > > Whenever we search in the index, our query is "TAG:TAG" to match all > > > documents, and we do the search like this: > > > > > > // Search > > > Hits h = searcher.search(q, cluCF, cluSort); > > > > > > cluCF is a ChainedFilter containing all the other filters (like > > > FOREIGN_PK=12345, TYPE=a, etc.). > > > > > > I know that the method is probably crazy because "TAG:TAG" is matching > > all > > > 300M documents and then it applies filters; so that's probably why > every > > > little query is taking 100% CPU/RAM.... but I don't know how to do it > > > properly. > > > > > > Help ! Any advice is welcome. > > > > > > - Mike > > > aka...@gmail.com > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > >
