--- Erik Hatcher <[EMAIL PROTECTED]> wrote:
> On Thursday, November 13, 2003, at 03:28 PM, Dan
> Quaroni wrote:
> > To my knowledge the answer is No, lucene performs
> each query
> > separately and
> > then performs the joins after it has all the
> results. This is
> > actually a
> > rather serious problem when it comes to searches
> in large indexes
> > where a
> > single field is very important but has a very low
> uniqueness.
> >
> > For example, if you were searching for a telephone
> number for a
> > company in a
> > lucene index of all of the companies in the US and
> you knew the state,
> > city,
> > and name, the query would come up being something
> like:
> >
> > name:Bob's Discount Furniture AND state:California
> AND city:San Diego
> >
> > Now, that query is going to retrieve EVERY Bob's
> discount furniture,
> > EVERY
> > company in California, and EVERY city in San Diego
> and then join them.
> > That
> > makes the memory requirements for this query far
> higher than they
> > really
> > need to be.
>
> If you know ahead of time that queries of this type
> would be made, then
> it could be "optimized" by doing the query that has
> the fewest hits
> first, then using a QueryFilter for successive
> queries to narrow it to
> the precise criteria. Granted this doesn't help
> when the queries can
> be entered free-form via QueryParser.
>
> Erik
Erik, Just to make sure I understand you right, In an
example query: ZipCode:CA10927 AND Gender:Male
Sure I know ZipCode returns fewer results, do you mean
I build a filter
QueryFilter x = new QueryFilter("ZipCode", "CA10927",
..);
Then build the query
Query y = QueryParser.parse("Gender:Male", "Gender",
..);
Then run it
Hit result = searcher.search(y, x);
I tried that, and the performance does not improve.
when I trace down the code, I found searcher object
searches on both ZipCode and Gender for terms
information (expesive) before processing on the
filters.
Am I doing something wrong, or you mean something
else? I would really appriciate if you can post an
example to this list, or send a copy of to my mail
address at [EMAIL PROTECTED]
Kind Regards
>
>
>
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