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https://issues.apache.org/jira/browse/LUCENE-3130?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13094554#comment-13094554
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Robert Muir commented on LUCENE-3130:
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Jan, not sure that most people only use single-term synonyms... if this is the
case maybe we should rethink our synonyms implementation because multi-word
adds a ton of complexity!
Another reason I suggested avoiding adding this to the core queryparser is
because its going to be challenging to allow this optional boosting in a
flexible way (just look at the getFieldQuery... its very hairy). I think in the
ideal case, we somehow restructure all this code so that subclasses have more
control over how the query is created... however I think this might be
challenging just given how the code is structured now.
The reason I think it would be best exposed as a 'hook' to subclasses (versus
adding a "deboost synonyms" option directly to the core QP), is that I think
people are going to want to customize how this works, e.g. control it per-field
and things like that.
At the end of the day, a queryparser could always subclass getFieldQuery
completely and do this now, but thats not great either because the code is so
hairy :(
This kind of feature might be easier to implement with the new queryparser in
contrib, but I'm not sure.
> Use BoostAttribute in in TokenFilters to denote Terms that QueryParser should
> give lower boosts
> -----------------------------------------------------------------------------------------------
>
> Key: LUCENE-3130
> URL: https://issues.apache.org/jira/browse/LUCENE-3130
> Project: Lucene - Java
> Issue Type: Improvement
> Reporter: Hoss Man
>
> A recent thread asked if there was anyway to use QueryTime synonyms such that
> matches on the original term specified by the user would score higher then
> matches on the synonym. It occurred to me later that a float Attribute could
> be set by the SynonymFilter in such situations, and QueryParser could use
> that float as a boost in the resulting Query. IThis would be fairly
> straightforward for the simple "synonyms => BooleamQuery" case, but we'd have
> to decide how to handle the case of synonyms with multiple terms that produce
> MTPQ, possibly just punt for now)
> Likewise, there may be other TokenFilters that "inject" artificial tokens at
> query time where it also might make sense to have a reduced "boost" factor...
> * SynonymFilter
> * CommonGramsFilter
> * WordDelimiterFilter
> * etc...
> In all of these cases, the amount of the "boost" could me configured, and for
> back compact could default to "1.0" (or null to not set a boost at all)
> Furthermore: if we add a new BoostAttrToPayloadAttrFilter that just copied
> the boost attribute into the payload attribute, these same filters could give
> "penalizing" payloads to terms when used at index time) could give
> "penalizing" payloads to terms.
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