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From "Robert Muir (JIRA)" <j...@apache.org>
Subject [jira] Commented: (LUCENE-2458) queryparser makes all CJK queries phrase queries regardless of analyzer
Date Fri, 28 May 2010 16:19:36 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-2458?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12873035#action_12873035
] 

Robert Muir commented on LUCENE-2458:
-------------------------------------

ok i revised the idea here:

in 3.1 we supply a patch that looks like this one, except, there is a simple boolean toggle
too. 
if you want per-field behavior or more explicit customization, you can subclass.
the simple toggle is for non-subclassers.

in 4.0 we do the same thing, for now.

we open a separate issue where we replace the QP with something better (that does not split
on whitespace 
at all and allows multi-word syns, n-gram tokenization, vietnamese, etc to work)

as part of that issue take the existing one (with per-field toggle) and call it classicqueryparser
or whatever.


> queryparser makes all CJK queries phrase queries regardless of analyzer
> -----------------------------------------------------------------------
>
>                 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, LUCENE-2458.patch
>
>
> The queryparser automatically makes *ALL* CJK, Thai, Lao, Myanmar, Tibetan, ... queries
into phrase queries, even though you didn't ask for one, and there isn't a way to turn this
off.
> This completely breaks lucene for these languages, as it treats all queries like 'grep'.
> Example: if you query for f:abcd with standardanalyzer, where a,b,c,d are chinese characters,
you get a phrasequery of "a b c d". if you use cjk analyzer, its no better, its a phrasequery
of  "ab bc cd", and if you use smartchinese analyzer, you get a phrasequery like "ab cd".
But the user didn't ask for one, and they cannot turn it off.
> The reason is that the code to form phrase queries is not internationally appropriate
and assumes whitespace tokenization. If more than one token comes out of whitespace delimited
text, its automatically a phrase query no matter what.
> The proposed patch fixes the core queryparser (with all backwards compat kept) to only
form phrase queries when the double quote operator is used. 
> Implementing subclasses can always extend the QP and auto-generate whatever kind of queries
they want that might completely break search for languages they don't care about, but core
general-purpose QPs should be language independent.

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