Hello,
I know this is a perennial question here because I've spent a lot of time
searching for an answer. I've seen the discussions about the TooManyClauses
exception and I understand generally why you get the it. I see lots of
discussion about using filters to avoid it but I still can't get it to work. I
think I'm just missing something fundamental.
I'm using Lucene 3.0.
I'm trying to do prefix queries on an index. I figured there might be times
where I might run into the TooManyClauses exception so from reading discussions
on the issue I figured I should use a filter. I found the PrefixFilter class
and began experimenting with it. E.g. this works:
QueryParser queryParser = new QueryParser(Version.LUCENE_30, "my_field", new
StandardAnalyzer(Version.LUCENE_30));
Query prefixQuery = queryParser.parse("t*");
PrefixFilter prefixFilter = new PrefixFilter(new Term("my_field", "t"));
indexSearcher.search(prefixQuery, prefixFilter, collector);
This returns about 5000 hits on my index.
But then I discovered that it works just as well without the filter:
QueryParser queryParser = new QueryParser(Version.LUCENE_30, "my_field", new
StandardAnalyzer(Version.LUCENE_30));
Query prefixQuery = queryParser.parse("t*");
indexSearcher.search(prefixQuery, collector);
Why, I don't know. Seems like this would get expanded out into 5000
BooleanQueries and since my max clause count is still set to the default 1024 I
should get the exception. But I didn't. So maybe I don't need the filter
after all?
Next, I need scoring to work. I read that with wildcard queries all scores are
set to 1.0 by default. But I read you can use the
QueryParser.setMultiTermRewriteMethod() method to take scoring into account
again. So I tried:
QueryParser queryParser = new QueryParser(Version.LUCENE_30, "my_field", new
StandardAnalyzer(Version.LUCENE_30));
queryParser.setMultiTermRewriteMethod(MultiTermQuery.SCORING_BOOLEAN_QUERY_REWRITE);
Query prefixQuery = queryParser.parse("t*");
indexSearcher.search(prefixQuery, collector);
Now, I get the TooManyClauses exception.
I tried adding the PrefixFilter back in but with no luck. Still get the
exception.
Again, sorry if this has been discussed before. Just not seeing an answer to
this after much searching and I just don't understand what is going on here.
Any help appreciated. Links welcome.
Bill
