In my Rails application I have a Question model, setup with sunspot solr, with a field "text" and I'd like to search in that field doing a logical OR between words. I've found that setting minimum_match to 1 solves my problem, however I'd like also to order the results by boosting questions that have more than 1 word matching. Is there a way to do this with Solr? The documentation isn't really helpful about ranking functions.
Edit: this is the full query I'm performing in the controller
#questions = Question.solr_search do
fulltext params[:query], :minimum_match => 1
end.results
According to http://wiki.apache.org/solr/SchemaXml,
The default operator used by Solr's query parser (SolrQueryParser) can
be configured with
<solrQueryParser defaultOperator="AND|OR"/>.
The default operator is "OR" if unspecified. It is preferable to not use
or rely on this setting; instead the request handler or query
LocalParams should specify the default operator. This setting here can
be omitted and it is being considered for deprecation.
You can change your defaultOperator in solr/conf/schema.xml or you could use LocalParams to specify OR via syntax like https://github.com/sunspot/sunspot/wiki/Building-queries-by-hand
It is true Sunspot's default operator is "AND", as referenced in https://github.com/sunspot/sunspot/blob/master/sunspot_solr/solr/solr/conf/schema.xml
Logical OR is the default behavior of the Dismax request handler used in Sunspot.
Plus, the more words match, the higher the document's score (which sounds like what you want)
Question.search do
fulltext 'best pizza'
end
...should return results that match one or both words (returning the ones that match both first):
"Joe's has the best pizza by the slice in NYC"
"It's hard to say which pizza place is the best"
"Pizza isn't the best food for you"
"I don't care whether pizza is bad for you!"
"What do you think the best type of fast food is?"
minimum_match is useful only if you want to filter out low relevance results (where only a certain low number or percentage of terms were actually matched). This doesn't affect scoring or logical OR/AND behavior.
Related
I'm attempting to query solr for documents, given a basic schema with the following field names, data types irrelevant:
I'm attempting to match documents that match at least one of the following:
occupation, name, age, gender but i want to OR them together
How do you OR together many terms, and enforce the document to match at least one?
This seems to be failing: +(name:Sarah age:24 occupation:doctor gender:male)
How do you convert a boolean expression into solr query syntax? I can't figure out the syntax with + and - and the default operator for OR.
Still I don't get your requirement but you just need to query like:
+(age:24 OR gender:male)
Or if you want data for multiple value in same field with OR condition like.
i.e. You get data of age:24 and age:25 both.
+(age:24 OR age:25 OR gender:male)
Then you can:
+(age:(24 25) OR gender:male)
If it is't your requirement, then let me know.
If you want to make it as simple as possible for the client, just go for the dismax[1] or edismax[2] query parser.
Specifically you can configure a request parameter called "qf" :
"The qf parameter introduces a list of fields, each of which is assigned a boost factor to increase or decrease that particular field’s importance in the query. For example, the query below:
qf=fieldOne^2.3 fieldTwo fieldThree^0.4
assigns fieldOne a boost of 2.3, leaves fieldTwo with the default boost (because no boost factor is specified), and fieldThree a boost of 0.4.
These boost factors make matches in fieldOne much more significant than matches in fieldTwo, which in turn are much more significant than matches in fieldThree." from the wiki
Then you can just pass a free text query, and it will be searched in the fields you specified, giving also different importance to each one, if necessary.
[1] https://lucene.apache.org/solr/guide/6_6/the-dismax-query-parser.html
[2] https://lucene.apache.org/solr/guide/6_6/the-extended-dismax-query-parser.html
I'm looking into the possibility of de-boosting a set of documents during
query time. In my application, when I search for e.g. "preferences", I want
to de-boost content tagged with ContentGroup:"Developer" or in other words,
push those content back in the order. Here's the catch. I've the following
weights on query fields and boost query on source
qf=text^6 title^15 IndexTerm^8
As you can see, title has a higher weight.
Now, a bunch of content tagged with ContentGroup:"Developer" consists of a
title like "Preferences.material" or "Preferences Property" or
"Preferences.graphics". The boost on title pushes these documents at the
top.
What I'm looking is to see if there's a way to deboost all documents that are
tagged with ContentGroup:"Developer" irrespective of the term occurrence is
text or title. I tried something like, but didn't make any difference.
Source:simplecontent^10 Source:Help^20 (-ContentGroup-local:("Developer"))^99
I'm using edismax query parser.
Any pointers will be appreciated.
Thanks,
Shamik
You're onto something with your last attempt, but you have to start with *:*, so that you actually have something to subtract the documents from. The resulting set of documents (those not matching your query) can then be boosted.
From the Solr Relevancy FAQ
How do I give a negative (or very low) boost to documents that match a query?
True negative boosts are not supported, but you can use a very "low" numeric boost value on query clauses. In general the problem that confuses people is that a "low" boost is still a boost, it can only improve the score of documents that match. For example, if you want to find all docs matching "foo" or "bar" but penalize the scores of documents matching "xxx" you might be tempted to try...
q = foo^100 bar^100 xxx^0.00001 # NOT WHAT YOU WANT
...but this will still help a document matching all three clauses score higher then a document matching only the first two. One way to fake a "negative boost" is to give a large boost to everything that does not match. For example...
q = foo^100 bar^100 (*:* -xxx)^999
NOTE: When using (e)dismax, people sometimes expect that specifying a pure negative query with a large boost in the "bq" param will work (since Solr automatically makes top level purely negative positive queries by adding an implicit ":" -- but this doesn't work with "bq", because of how queries specified via "bq" are added directly to the main query. You need to be explicit...
?defType=dismax&q=foo bar&bq=(*:* -xxx)^999
I implementing Solr search using an API. When I call it using the parameters as, "Chillout Lounge", it returns me the collection which are same/similar to the string "Chillout Lounge".
But when I search for "Chillout Lounge Box", it returns me results which don't have any of these three words.(in the DB there are values which have these 3 values, but they are not returned.)
According to me, Solr uses Fuzzy search, but when it is done it should return me some values, which will have at least one these value.
Or what could be the possible changes I should to my schema.XML, such that is would give me proper values.
First of all - "Fuzzy search" is a feature you'll have to ask for (by using ~ in standard Lucene query syntax).
If you're talking about regular searches, you can use q.op to select which operator to use. q.op=AND will make sure that all the terms match, while q.op=OR will make any document that contain at least one of the terms be returned. As long as you aren't using fq for this, the documents that match more terms should be scored higher (as the score will add up across multiple terms), and thus, be shown higher in the result set.
You can use the debug query feature in the web interface to see scores for each term for a document, and find out why the document was returned at all. If the document doesn't match any terms, it shouldn't be returned, unless you're asking for all documents to be returned.
Be aware that the analyzer chain defined for the field you're searching might affect what's considered a match and not.
You'll have to add a proper example to get a more detailed answer.
I am trying to set up Solr but encountered the problem mentioned in the title. I just downloaded Solr and used the built-in example. When I used a query with words occurred in the example documents, such as "ipod". Solr worked properly. However, when I added some words that are not in these documents, such as "what". Solr does not return anything. For me, it is weird since the relevance scores should be computed to query terms separately and added up. Non-existing query term should not affect the ranking (even though the coord norm is affected, thus the scores of documents will change).
Could anyone tell me what might be the issue? Thanks.
There are several ways of configuring how you want this behavior. I'll assume that you're using the edismax query handler for these examples, although some of these also apply to the standard lucene query parser.
The reason for not always wanting "ipod what" to retrieve the same subset sa "ipod" is that you'll get a poor result set and user experience for terms that are more general than "ipod" (i.e. searching for "microsoft windows" will not be perceived as a good search result if you're showing only general hits for anything about windows - it's usually better to say "we didn't find anything" in those cases). It all depends on your use case.
First, you can do it yourself, by applying either AND or OR between terms to get the exact kind of matching you're looking for.
You can use q.op to configure wether each term should be AND-ed together (all required) or OR-ed together (any one is sufficient). This overrides the (now deprecated) value from <solrQueryParser defaultOperator=".."/> in schema.xml.
For (e)dismax, there's the mm parameter, which allows you do more specific, but in a general way, handling of how you want matches to be performed. mm allows you to say "at least 50% of the terms should match" or "if there's only two terms, both should match, but any over that should be optional" or "match everything up to four, and 75% after that".
Is there a way to specify a set of terms that are more important when performing a search?
For example, in the following question:
"This morning my printer ran out of paper"
Terms such as "printer" or "paper" are far more important than the rest, and I don't know if there is a way to list these terms to indicate that, in the global knowledge, they'd have more weight than the rest of words.
For specific documents you can use QueryElevationComponent, which uses special XML file in which you place your specific terms for which you want specific doc ids.
Not exactly what you need, I know.
And regarding your comment about users not caring what's underneath, you control the final query. Or, in the worst case, you can modify it after you receive it at Solr server side.
Similar: Lucene term boosting with sunspot-rails
When you build the query you can define what are the values and how much these fields have weight on the search.
This can be done in many ways:
Setting the boost
The boost can be set by using "^ "
Using plus operator
If you define + operator in your query, if there is a exact result for that filed value it is shown in the result.
For a better understanding of solr, it is best to get familiar with lucene query syntax. Refer to this link to get more info.