I am using Lucene.net via Kentico. I am trying to boost results that have a particular value in a field. For example:
myfield:"myvalue"^2
Unfortunately this is treated as a search term and alters the scores (via tf and idf etc) anyway.
Is there a way of boosting a result based on the presence of a value, but not including that value as a search term?
update
So I want to boost the score of records that contain that value in that field only, its not a search value in any way.
Failing that, as I am actually using two indexes, could I apply a boost to a particular index? For example, items from in index-1 have a slightly higher score overall than those from index-2
If you added this field in the "Search Condition" then behind the scenes it adds a "+" to the value, so the lucene is rendering:
+(myfield:"myvalue"^2)
Which then requires the field.
I believe (you will have to test) if you add a Smart Search Filter, set the value to myfield:"myValue"^2 and then set the "Filter is conditional" to false, this should properly add in your field to the lucene to boost, then just wrap the filter with some <div style="display:none"></div> to hide it.
Point that to your Results and see if it does the trick!
Related
I'm using AWS CloudSearch for a search index, and the user can currently search over it for records which match the name field and a few others. However, we have users in different languages and I would like to give a boost to results which match their local language. Every record has a locale field, which could be a facet. However, I don't want to simply exclude results which don't match, and nor do I want to simply sort it so that everything in their language always comes first regardless of 'relevance' - I simply want to give a 'boost' to any result where locale=<my locale>.
In other words, I would like highly relevant matches in a different locale to still beat barely relevant matches in my own language, but relevant matches in my own language should definitely rank higher than matches in a different language.
Is there a way to do this when I query CloudSearch or should I just do the reordering client side once I have fetched all of the results?
So this was painfully convoluted but I did manage to get it to work in the end. If you are doing a structured search (q.parser=structured) then you can perform a query that receives a boost if the locale field matches a given value.
Sadly, where it gets a bit cumbersome, is that it doesn't really seem to be designed for boosting things that match something other than your main query, so by default it filters out anything that doesn't match the locale and excludes them entirely from the results. So you have to combine two versions of the query with an (or) - one with the boost and one without.
So my basic query (which in my case was already (or 'un' (prefix 'un'))) now becomes (or (and <OLD_QUERY> (term field=locale boost=2.5 'en')) <OLD_QUERY>)
In other words: EITHER a match for the original query where locale='en', boosted by 2.5, OR a match for that same query in any locale without a boost.
Painful, but it works!
I am using Solr 4.1.0 and I'm facing a strange issue. If I give a value to search for a field, even be it exact or involving a wildcard, it gives me 0 search results. On the other hand if I just give the field name and a * in place of value, I get all the results.
Also, if I search in the text field, i.e where I have copied values of all my fields, it gives me correct output. text is by default, my catch-all for all fields. feature is a field which has value Butter.
So now, what is happening here is that if I try to find in the actual field with the exact value or even with starting alphabet and a *, it doesn't give me a value while if I search in the text field, which is a catch-all field, I'm able to retrieve the value. Although if I try to find in the feature field using *, it gives me complete result list correctly.
You can view the logs for text:Butter here, logs for feature:Butter here, logs for feature:B* here and logs for feature:* here
I'm facing this issue with this particular field only. Any pointers to what could be the reason behind this strange problem?
If you search without the field name, Solr is going to search in the default search field.
So make sure you are marking the fields you want to search on as default.
If you are using dismax query handler, you can add them to the qf parameter.
Also, for Wildcard Queries check [Analyzers][1]
On wildcard and fuzzy searches, no text analysis is performed on the search word.
As no analysis is done at query time for wilcard searches and hence the lower casing, stemming would not be applied during query time but just the index time.
I have a database which I have indexed in Lucene (using Pylucene) by section (specified by markup in the document) using lucene's fields. This index seems to work fine. I can search it using the default field which is simply the entire document and get reasonable results.
The problem is, when I search it using a specific section (not the default), I expect to get a certain number of results back (as specified by IndexSearcher.search(query, results)), but instead it might simply return nothing. So my question is: how can I get it to return a ranked list with the number of results I specify?
The only place I specify the field is in the QueryParser, by calling:
QueryParser(Version.LUCENE_CURRENT, field, StandardAnalyzer)
I would verify the index using Luke (which is something I do often when modifying my index strategy).
In my case, documents have two fields, for example, "title" and "views". "views" is represented the num of times that people have visited this document. like: "title":"iphone", "views":"10".
I have to develop a strategy that will assign some weights to views, such as the relevance score is calculated by score(title)*0.8+score(views)*0.2. Does lucene can do this? And I want to know whether there are some algorithms related to this question.
If you get here after 2020, in Lucene 8.5.2.
Document.setBoost() doesn't exist anymore.
Field.setBoost() doesn't exist anymore.
Query.setBoost() doesn't exist anymore.
The ways to go:
Wrap your Query (any Query but probably TermQuery in this case) in à BoostQuery
Query boosted = new BoostQuery(query, 2f);
Use the caret ^ symbol in your query parser syntax.
Specify boosts in MultiFiledQueryParser.
Use PerFieldSimilarityWrapper and adjust score per field.
Here is how you can do that:
Query titleQuery, viewsQuery;
titleQuery.setBoost(0.8);
viewsQuery.setBoost(0.2);
BooleanQuery query = new BooleanQuery();
query.add(titleQuery, Occur.MUST); // or Occur.SHOULD if this clause is optional
query.add(viewsQuery, Occur.SHOULD); // or Occur.MUST if this clause is required
// use query to search documents
The score will be proportional to 0.8*score(titleQuery) + 0.2*score(viewsQuery) (to a multiplicative constant).
To leverage your views field, you will probably need to use a ValueSourceQuery.
You can boost in 3 ways. Depending on your needs you might want to employ a combination
Document level boosting - while indexing - by calling
document.setBoost() before a document is added to the index.
Document's Field level boosting - while indexing - by calling
field.setBoost() before adding a field to the document (and before
adding the document to the index).
Query level boosting - during
search, by setting a boost on a query clause, calling
Query.setBoost().
source: http://lucene.apache.org/core/old_versioned_docs/versions/3_0_0/scoring.html
In my Lucene documents I have a field "company" where the company name is tokenized.
I need the tokenization for a certain part of my application.
But for this query, I need to be able to create a PrefixQuery over the whole company field.
Example:
My Brand
my
brand
brahmin farm
brahmin
farm
Regularly querying for "bra" would return both documents because they both have a term starting with bra.
The result I want though, would only return the last entry because the first term starts with bra.
Any suggestions?
Create another indexed field, where the company name is not tokenized. When necessary, search on that field rather than the tokenized company name field.
If you want fast searches, you need to have index entries that point directly at the records of interest. There might be something that you can to with the proximity data to filter records, but it will be slow. I see the problem as: how can a "contains" query over a complete field be performed efficiently?
You might be able to minimize the increase in index size by creating (for each current field) a "first term" field and "remaining terms" field. This would eliminate duplication of the first term in two fields. For "normal" queries, you look for query terms in either of these fields. For "startswith" queries, you search only the "first term" field. But this seems like more trouble than it's worth.
Use a SpanQuery to only search the first term position. A PrefixQuery wrapped by SpanMultiTermQueryWrapper wrapped by SpanPositionRangeQuery:
<SpanPositionRangeQuery: spanPosRange(SpanMultiTermQueryWrapper(company:bra*), 0, 1)>