Hi,
My experience is that the BQ parameter can be used with any query type.
You can define boosts on the query fields (qf) that are used with the
query terms (q) in your query, AND you can define additional boosts for
fields that are not used with the query terms through the bq or bf
parameters.
I think the relative weight that assigning a particular boost to a field
via BQ has on the overall scoring needs to take into consideration the
other fields in your query. If you're searching on titles, you might
want to consider setting omitNorms=true (means don't generate length
normalization vectors) for title in your schema.xml, and if you're using
Solr 1.4 omitTf=true (means don't generate term frequency vectors), so
that results aren't skewed by short and long titles, or titles that
contain multiple occurrences of the same term (setting these requires
you to reindex). I think this should have the effect of making BQ boosts
like bq=media:DVD^2bq=media:BLU-RAY^1.5 more effective.
-- Dean
-Original Message-
From: Pete Smith [mailto:pete.sm...@lovefilm.com]
Sent: 13/03/2009 7:11 PM
To: solr-user@lucene.apache.org
Subject: Re: How to correctly boost results in Solr Dismax query
Hi,
On Fri, 2009-03-13 at 03:57 -0700, dabboo wrote:
bq works only with q.alt query and not with q queries. So, in your
case you
would be using qf parameter for field boosting, you will have to give
both
the fields in qf parameter i.e. both title and media.
try this
str name=qfmedia^1.0 title^100.0/str
But with that, how will it know to rank media:DVD higher than
media:BLU-RAY?
Cheers,
Pete
Pete Smith-3 wrote:
Hi Amit,
Thanks again for your reply. I am understanding it a bit better but
I
think it would help if I posted an example. Say I have three
records:
doc
long name=id1/long
str name=mediaBLU-RAY/str
str name=titleIndiana Jones and the Kingdom of the Crystal
Skull/str
/doc
doc
long name=id2/long
str name=mediaDVD/str
str name=titleIndiana Jones and the Kingdom of the Crystal
Skull/str
/doc
doc
long name=id3/long
str name=mediaDVD/str
str name=titleCasino Royale/str
/doc
Now, if I search for indiana: select?q=indiana
I want the first two rows to come back (not the third as it does not
contain 'indiana'). I would like record 2 to be scored higher than
record 1 as it's media type is DVD.
At the moment I have in my config:
str name=qftitle/str
And i was trying to boost by media having a specific value by using
'bq'
but from what you told me that is incorrect.
Cheers,
Pete
On Fri, 2009-03-13 at 03:21 -0700, dabboo wrote:
Pete,
Sorry, if wasnt clear. Here is the explanation.
Suppose you have 2 records and they have films and media as 2
columns.
Now first record has values like films=Indiana and media=blue
ray
and 2nd record has values like films=Bond and media=Indiana
Values for qf parameters
str name=qfmedia^2.0 films^1.0/str
Now, search for q=Indiana .. it should display both of the records
but
record #2 will display above than the 1st.
Let me know if you still have questions.
Cheers,
amit
Pete Smith-3 wrote:
Hi Amit,
Thanks very much for your reply. What you said makes things a bit
clearer but I am still a bit confused.
On Thu, 2009-03-12 at 23:14 -0700, dabboo wrote:
If you want to boost the records with their field value then you
must
use
q
query parameter instead of q.alt. 'q' parameter actually uses qf
parameters
from solrConfig for field boosting.
From the documentation for Dismax queries, I thought that q is
simply
a keyword parameter:
From http://wiki.apache.org/solr/DisMaxRequestHandler:
q
The guts of the search defining the main query. This is
designed to
be
support raw input strings provided by users with no special
escaping.
'+' and '-' characters are treated as mandatory and
prohibited
modifiers for the subsequent terms. Text wrapped in balanced
quote
characters '' are treated as phrases, any query containing an
odd
number of quote characters is evaluated as if there were no quote
characters at all. Wildcards in this q parameter are not
supported.
And I thought 'qf' is a list of fields and boost scores:
From http://wiki.apache.org/solr/DisMaxRequestHandler:
qf (Query Fields)
List of fields and the boosts to associate with each of them
when
building DisjunctionMaxQueries from the user's query. The format
supported is fieldOne^2.3 fieldTwo fieldThree^0.4, which
indicates that
fieldOne has a boost of 2.3, fieldTwo has the default boost, and
fieldThree has a boost of 0.4 ... this indicates that matches in
fieldOne are much more significant than matches in fieldTwo,
which are
more significant than matches in fieldThree.
But if I want to, say, search for films with 'indiana' in the
title,
with media=DVD scoring higher than
