its not just CJK queries, its in general any language not separated on whitespace.
There are a lot of other languages that don't use whitespace the same way english does. On Sun, May 23, 2010 at 12:47 PM, Shai Erera <ser...@gmail.com> wrote: > Robert - I hope hitting the keyboard hard makes you happy :) > > I do get the issue. And I still think that CJK queries are just a small > percentage of all queries that are used in the world today. Or at least by > Lucene. And I'm not sure why we want to change the default for ALL OTHER > LANGUAGES, just so that CJK QUERIES will hAVe A diFFEreNT BeHAvioR > !!?!?!?!?!?!??!?!?! > > > > On Sun, May 23, 2010 at 7:42 PM, Robert Muir <rcm...@gmail.com> wrote: >> >> 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 >> > > -- Robert Muir rcm...@gmail.com --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org
