I'd think that if a user specified a query "cutting lucene", with an implicit AND and the default fields "title" and "author", they'd expect to see a match in which both "cutting" and "lucene" appears. That is,
(title:cutting OR author:cutting) AND (title:lucene OR author:lucene)
Your proposal is certainly an improvement.
It's interesting to note that in Nutch I implemented something different. There, a search for "cutting lucene" expands to something like:
(+url:cutting^4.0 +url:lucene^4.0 +url:"cutting lucene"~2147483647^4.0) (+anchor:cutting^2.0 +anchor:lucene^2.0 +anchor:"cutting lucene"~4^2.0) (+content:cutting +content:lucene +content:"cutting lucene"~2147483647)
So a page with "cutting" in the body and "lucene" in anchor text won't match: the body, anchor or url must contain all query terms. A single authority (content, url or anchor) must vouch for all attributes.
Note that Nutch also boosts matches where the terms are close together. Using "~2147483647" permits them to be anywhere in the document, but boosts more when they're closer and in-order. (The "~4" in anchor matches is to prohibit matches across different anchors. Each anchor is separated by a Token.positionIncrement() of 4.)
But perhaps this is not a feature. Perhaps Nutch should instead expand this to:
+(url:cutting^4.0 anchor:cutting^2.0 content:cutting) +(url:lucene^4.0 anchor:lucene^2.0 content:lucene) url:"cutting lucene"~2147483647^4.0 anchor:"cutting lucene"~4^2.0 content:"cutting lucene"~2147483647
That would, e.g., permit a match with only "lucene" in an anchor and "cutting" in the content, which the earlier formulation would not.
Can anyone tell whether Google has this requirement? I have not been able to construct a two-word query that returns a page without both words in either the content, the title, the url or in a single anchor. Can you?
If you're interested, the Nutch query expansion code in question is:
http://cvs.sourceforge.net/viewcvs.py/nutch/nutch/src/plugin/query-basic/src/java/net/nutch/searcher/basic/BasicQueryFilter.java?view=markup
To play with it you can download Nutch and use the command:
bin/nutch net.nutch.searcher.Query
http://issues.apache.org/eyebrowse/[EMAIL PROTECTED]&msgId=1798116
Yes, the approach there is similar. I attempted to complete the solution and provide a working replacement for MultiFieldQueryParser.
But, inspired by that message, couldn't MultiFieldQueryParser just be a subclass of QueryParser that overrides getFieldQuery()?
Cheers,
Doug
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