These comments lead me to believe you don't understand the issue. Do you understand that *ALL* CJK queries are made into phrase queries, regardless of tokenizer?!!?!?!
On Sun, May 23, 2010 at 12:38 PM, Uwe Schindler <u...@thetaphi.de> wrote: > Same here, as already noted in the issue. > > > > Uwe > > > > ----- > > Uwe Schindler > > H.-H.-Meier-Allee 63, D-28213 Bremen > > http://www.thetaphi.de > > eMail: u...@thetaphi.de > > > > From: Shai Erera [mailto:ser...@gmail.com] > Sent: Sunday, May 23, 2010 6:34 PM > > To: dev@lucene.apache.org > Subject: Re: [jira] Commented: (LUCENE-2458) queryparser shouldn't generate > phrasequeries based on term count > > > > Robert - is the effect on scoring also on English and other European > languages? Or is it mostly for ngram-based languages, and especially CJK? > > I want to stress that not all ngram-based languages are affected by this > behavior, especially those for which we do ngram just because of a lack of > good tokenizer. > > That's why I'm not sure the default should be changed and I'm all for a > getter/setter. If however it turns out the default MUST be changed, then I > support the Version + getter/setter approach. > > Shai > > On Sun, May 23, 2010 at 6:00 PM, Uwe Schindler (JIRA) <j...@apache.org> > wrote: > > [ > https://issues.apache.org/jira/browse/LUCENE-2458?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12870410#action_12870410 > ] > > Uwe Schindler commented on LUCENE-2458: > --------------------------------------- > > Hi Robert, > > I also agree with Mark (as you know). We can have both: > - Version for a good default (3.1 will get the new non-phrase-query > behavior) > - A separate getsetter for this option > (set/getCreatePhraseQueryOnConcenattedTerms or whatever) > > This would give you the best from both worlds. > >> queryparser shouldn't generate phrasequeries based on term count >> ---------------------------------------------------------------- >> >> Key: LUCENE-2458 >> URL: https://issues.apache.org/jira/browse/LUCENE-2458 >> Project: Lucene - Java >> Issue Type: Bug >> Components: QueryParser >> Reporter: Robert Muir >> Assignee: Robert Muir >> Priority: Blocker >> Fix For: 3.1, 4.0 >> >> Attachments: LUCENE-2458.patch, LUCENE-2458.patch >> >> >> The current method in the queryparser to generate phrasequeries is wrong: >> The Query Syntax documentation >> (http://lucene.apache.org/java/3_0_1/queryparsersyntax.html) states: >> {noformat} >> A Phrase is a group of words surrounded by double quotes such as "hello >> dolly". >> {noformat} >> But as we know, this isn't actually true. >> Instead the terms are first divided on whitespace, then the analyzer term >> count is used as some sort of "heuristic" to determine if its a phrase query >> or not. >> This assumption is a disaster for languages that don't use whitespace >> separation: CJK, compounding European languages like German, Finnish, etc. >> It also >> makes it difficult for people to use n-gram analysis techniques. In these >> cases you get bad relevance (MAP improves nearly *10x* if you use a >> PositionFilter at query-time to "turn this off" for chinese). >> For even english, this undocumented behavior is bad. Perhaps in some cases >> its being abused as some heuristic to "second guess" the tokenizer and piece >> back things it shouldn't have split, but for large collections, doing things >> like generating phrasequeries because StandardTokenizer split a compound on >> a dash can cause serious performance problems. Instead people should analyze >> their text with the appropriate methods, and QueryParser should only >> generate phrase queries when the syntax asks for one. >> The PositionFilter in contrib can be seen as a workaround, but its pretty >> obscure and people are not familiar with it. The result is we have bad >> out-of-box behavior for many languages, and bad performance for others on >> some inputs. >> I propose instead that we change the grammar to actually look for double >> quotes to determine when to generate a phrase query, consistent with the >> documentation. > > -- > This message is automatically generated by JIRA. > - > You can reply to this email to add a comment to the issue online. > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org > > For additional commands, e-mail: dev-h...@lucene.apache.org > > -- Robert Muir rcm...@gmail.com --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org
