I would like to apply negative boost on the documents which does not have specific fields. But its not working and results the same boost value for the document with and without that field.Any pointers would be of great help.
bf=if(not(exists('image-small_string')),0,-500)
The answer is to boost those documents that do not match your query, instead of trying to apply a negative boost to those that do.
To boost documents that has a specific field, you can use bq=foo:[* TO *]^5 (and adjust the boost factory to match the behaviour you're looking for).
Related
We're working on a plan to identify content tags our users are interested in. So, for instance, we may determine that User X consumes content tagged with "kermit" and "piggy" more often than other tags. These are their "favored tags."
When the users search, we'd like to favor/bias documents that contain these terms.
This means we can't boost the documents at index time, because every user will have different favored tags. Additionally, they may not be searching for the favored tags themselves. They may search for "gonzo," and so we absolutely want to give them documents with "gonzo," but we want to boost documents that also contain "kermit" or "piggy."
These favored tags are not used to actually query the index, but rather are used to bias the result ordering. The favored tags become something of a tie-breaker -- all else being equal, documents containing these terms will rank higher.
This is new/planned development, so we can use whatever version and parser stack is optimal to solve this problem.
Solution in SolrNet
The question was correctly answered below, but here's the code for SolrNet just in case someone else is using it.
var localParams = new LocalParams();
localParams.Add("bq", "kermit^10000); //numeric value is the degree of boost
var solr = ServiceLocator.Current.GetInstance<ISolrOperations<MySolrDocumentClass>>();
solr.Query(new SolrQuery("whatever") + localParams);
You didn't specify which query parser you're using, but if you are using the Dismax or Extended Dismax query parser, the bq argument should do exactly what you're looking for. bq adds search criteria to a search solely for the purpose of affecting the relevancy, but not to limit the result set.
From the Dismax documentation:
The bq (Boost Query) Parameter
The bq parameter specifies an additional, optional, query clause that
will be added to the user's main query to influence the score. For
example, if you wanted to add a relevancy boost for recent documents:
q=cheese
bq=date:[NOW/DAY-1YEAR TO NOW/DAY]
You can specify multiple bq parameters. If you want your query to be
parsed as separate clauses with separate boosts, use multiple bq
parameters.
In this case, you may want to add &bq=kermit&bq=piggy to the end of your Solr query. If you aren't using one of these query parsers, this need may be exactly the motivation you need to switch.
As the title says which one I need to use for boosting in solr. whether its q.alt or bq. I tried the boosting in both however I'm not clear on how the boosting is working. Because in q.alt I got the correct results when I specified boosting value as 1000 at the same time I got the same results in bq with the boosting value as 2
Can someone help me to get the best practices for boosting?
My SOLR version is 3.5.
It depends upon what are you trying to boost.
Use qf (query fields) - to boost the individual search fields which have different weightage.
for e.g. For a document title has a higher weightage then description then you would use title^2 description^1
q.alt is just an alternate query factor in case on q is specified.
Use bq and bf for boosting certain matches, ranges or when the need to apply some functions on them. These usually are the extar boost and not the part of the search boost.
for e.g. for latest documents you would boost by date, or Price range or you want to boost on sum of fields etc ...
use qf parameter for boosting
Dismax Query Parser Wiki
I'm doing a "More Like This" query on 3 text fields, but I'd like to also boost the results based on a numeric "views" field. In a normal query I'd add a boost term like "{!boost b=scale(sqrt(views),1,2)}" or something similar, but this doesn't seem to work if I specify it in the mlt.qf field. Is formula based boosting allowed in MLT queries?
According to the More Like This page on the Solr Wiki, the mlt.qf field allows for boosts.
Query fields and their boosts using the same format as that used in DisMaxQParserPlugin. These fields must also be specified in mlt.fl.
Checkout the syntax for boosting with the DisMaxQParserPlugin and you should be able to get the boosting you desire.
Also, check out the answer to this previous question - Is it possible to boost mlt queries in Solr
I have a more like this query which I would like to update to return newer documents first. According to the documentation, I would need to add recip(ms(NOW,mydatefield),3.16e-11,1,1) to my query.
But when I try to add it to either of mlt.qf or bf parameters. The results stay exactly the same.
This is my query:
/solr/mlt?
q=id:cms.article.137861
&defType=edismax
&rows=3
&indent=on
&mlt.fl=series_id,tags,title,text
&mlt.qf=show_id text^1.1 title^1.1 tags^90
&wt=json
&fl=url,title,tags,django_id,content_type_id
&bf=recip(ms(NOW,pub_date),3.16e-11,1,1)
this is taken from the solr wiki (its down but i have it cached)
i think this is what you are looking for.
How can I boost the score of newer documents
Do an explicit sort by date (relevancy scores are ignored)
Use an index-time boost that is larger for newer documents
Use a FunctionQuery to influence the score based on a date field.
In Solr 1.3, use something of the form recip(rord(myfield),1,1000,1000)
In Solr 1.4, use something of the form recip(ms(NOW,mydatefield),3.16e-11,1,1)
http://lucene.apache.org/solr/api/org/apache/solr/search/function/ReciprocalFloatFunction.html http://lucene.apache.org/solr/api/org/apache/solr/search/BoostQParserPlugin.html
A full example of a query for "ipod" with the score boosted higher the newer the product is:
http://localhost:8983/solr/select?q={!boost b=recip(ms(NOW,manufacturedate_dt),3.16e-11,1,1)}ipod
One can simplify the implementation by decomposing the query into multiple arguments:
http://localhost:8983/solr/select?q={!boost b=$dateboost v=$qq}&dateboost=recip(ms(NOW,manufacturedate_dt),3.16e-11,1,1)&qq=ipod
Now the main "q" argument as well as the "dateboost" argument may be specified as defaults in a search handler in solrconfig.xml, and clients would only need to pass "qq", the user query.
To boost another query type such as a dismax query, the value of the boost query is a full sub-query and hence can use the {!querytype} syntax. Alternately, the defType param can be used in the boost local params to set the default type to dismax. The other dismax parameters may be set as top level parameters.
http://localhost:8983/solr/select?q={!boost b=$dateboost v=$qq defType=dismax}&dateboost=recip(ms(NOW,manufacturedate_dt),3.16e-11,1,1)&qf=text&pf=text&qq=ipod
Consider using reduced precision to prevent excessive memory consumption. You would instead use recip(ms(NOW/HOUR,mydatefield),3.16e-11,1,1). See this thread for more information.
apparently your date field is not a TrieDate
I already have the boost determined before hand. I have a field in the solr index called boost1 . This boost field will have a value from 1 to 10 similar to google PR rank. This is the boost that should be applied to every query ran in solr. here are the fields in my index
Id
Title
Text
Boost1
The boost field should be apply to every query. I am trying to implement functionality similar to Google PR rank. Is there a way to do this using solr?
you can add the boost during query e.g.
q={!boost b=boost1}
How_can_I_boost_the_score_of_newer_documents
However, this may need to be added explicitly by you.
If you are using dismax or edismax with the request handler, The bf (Boost Functions) parameter could be used to boost the documents.
http://wiki.apache.org/solr/DisMaxQParserPlugin#bf_.28Boost_Functions.29
bf=boost1^0.5
This can be added to defaults with the request handler definition, so that they are applied to all the search queries.
you can use function queries to vary the amount of boost FunctionQuery
I think you need to use index time document boosts. See this if you are indexing XML or this if using DataImportHandler.