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From "Robert Muir (JIRA)" <>
Subject [jira] Commented: (LUCENE-2458) queryparser makes all CJK queries phrase queries regardless of analyzer
Date Fri, 28 May 2010 15:21:38 GMT


Robert Muir commented on LUCENE-2458:

i would suggest the following, a combination of mike, mark's, and yonik's ideas:

* in 3.1 we supply a patch that looks like this one, except, there is a toggle too. this toggle
can be per-field.
* 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.

i think we should consider the second separate issue carefully and take more time. I personally
would prefer
if somehow we could "tone down" the flexible queryparser (as far as number of classes, attributes,
etc) and 
use that as a base. There are things about it I like, and things I don't like, but overall
it seems to be a better
starting point for such a thing.

> queryparser makes all CJK queries phrase queries regardless of analyzer
> -----------------------------------------------------------------------
>                 Key: LUCENE-2458
>                 URL:
>             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
> 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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