qf boost Versus field boost for Dismax queries

[ashokc <as...@qualcomm.com>]

When 'dismax' queries are use, where is the best place to apply boost
values/factors? While indexing by supplying the 'boost' attribute to the
field, or in solrconfig.xml by specifying the 'qf' parameter with the same
boosts? What are the advantages/disadvantages to each? What happens if both
boosts are present? Do they get multiplied?

Thanks

- ashok
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Re: qf boost Versus field boost for Dismax queries

[Chris Hostetter <ho...@fucit.org>]

On Tue, 9 Jun 2009, ashokc wrote:

: When 'dismax' queries are use, where is the best place to apply boost
: values/factors? While indexing by supplying the 'boost' attribute to the
: field, or in solrconfig.xml by specifying the 'qf' parameter with the same
: boosts? What are the advantages/disadvantages to each? What happens if both

This is discussed in the Lucene-Java FAQ...

http://wiki.apache.org/lucene-java/LuceneFAQ#head-246300129b9d3bf73f597facec54ac2ee54e15d7

What is the difference between field (or document) boosting and query 
boosting?

Index time field boosts (field.setBoost(boost)) are a way to express 
things like "this document's title is worth twice as much as the title of 
most documents". Query time boosts (query.setBoost(boost)) are a way to 
express "I care about matches on this clause of my query twice as much as 
I do about matches on other clauses of my query".

Index time field boosts are worthless if you set them on every document.

Index time document boosts (doc.setBoost(float)) are equivalent to setting 
a field boost on ever field in that document. 




-Hoss

Re: qf boost Versus field boost for Dismax queries

[Otis Gospodnetic <ot...@yahoo.com>]

It's like cooking.  If you put too much salt in your food, it's kind of hard to undo that and you end up with a salty meal.  Boosting at search time makes it easy to change boosts (e.g. when trying to find the best boost values), while boosting at index time "hard-codes" them.  You can use both and they should be multiplied.

 Otis
--
Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch



----- Original Message ----
> From: ashokc <as...@qualcomm.com>
> To: solr-user@lucene.apache.org
> Sent: Tuesday, June 9, 2009 6:17:37 PM
> Subject: qf boost Versus field boost for Dismax queries
> 
> 
> When 'dismax' queries are use, where is the best place to apply boost
> values/factors? While indexing by supplying the 'boost' attribute to the
> field, or in solrconfig.xml by specifying the 'qf' parameter with the same
> boosts? What are the advantages/disadvantages to each? What happens if both
> boosts are present? Do they get multiplied?
> 
> Thanks
> 
> - ashok
> -- 
> View this message in context: 
> http://www.nabble.com/qf-boost-Versus-field-boost-for-Dismax-queries-tp23952323p23952323.html
> Sent from the Solr - User mailing list archive at Nabble.com.