At 4:40 PM +0100 6/6/07, galo wrote:
>1. I want to use solr for some sort of live search, querying with incomplete
>terms + wildcard and getting any similar results. Radioh* would return
>anything containing that string. The DisMax req. hander doesn't accept
>wildcards in the q param so i'm trying the simple one and still have problems
>as all my results are coming back with score = 1 and I need them sorted by
>relevance.. Is there a way of doing this? Why doesn't * work in dismax (nor ~
>by the way)??
DisMax was written with the intent of supporting a simple search box in which
one could type or paste some text, e.g. a title like
Santa Clause: Is he Real (and if so, what is "real")?
and get meaningful results. To do that it pre-processes the query string by
removing unbalanced quotation marks and escaping characters that would
otherwise be treated by the query parser as operators:
\ ! ( ) : ^ [ ] { } ~ * ?
I have a local version of DisMax which parameterizes the escaping so certain
operators can be allowed through, which I'd be happy to contribute to you or
the codebase, but I expect SimpleRH may be a better tool for your application
than DisMaxRH, as long as you get it to score as you wish.
Both Standard and DisMax request handlers use SolrQueryParser, an extension of
the Lucene query parser which introduces a small number of changes, one of
which is that prefix queries e.g. Radioh* are evaluated with
ConstantScorePrefixQuery rather than the standard PrefixQuery.
In issue SOLR-218 developers have been discussing per-field control of query
parser options (some of it Solr's, some of it Lucene's). When that is
implemented there should additionally be a property useConstantScorePrefixQuery
analogous to the unfortunately-named QueryParser useOldRangeQuery, but handled
by SolrQueryParser (until CSPQs are implemented as an option in Lucene QP).
Until that time, well, Chris H. posted a clever and rather timely workaround on
the solr-dev list:
>one work arround people may want to consider ... is to force the use of a
>WildCardQuery in what would otherwise be interpreted as a PrefixQuery by
>putting a "?" before the "*"
>
>ie: auto?* instead of auto*
>
>(yes, this does require that at least one character follow the prefix)
Perhaps that would help in your case?
- J.J.
