I want to retrieve some documents from SOLR and pass boosts to the field's so that they are returned in the order I request them (respectively the web request requests them). Therefore I add boosts to the desired ids:
q=myfield:"9125129"^10 OR
myfield:"9125417"^9 OR
myfield:"9124611"^8 OR
myfield:"9126980"^7 ...
fl=myfield
wt=csv
Unfortunately, this does not return the documents in the desired order:
myfield
9125129
9125417
9126980
9124611
If I change the query to
q=myfield:"9125129"^9 OR
myfield:"9125417"^8 OR
myfield:"9124611"^7 OR
myfield:"9126980"^6 ...
fl=myfield
wt=csv
(just for testing), the correct order is returned:
myfield
9125129
9125417
9124611
9126980
So it seems like SOLR does not like the double-digit boost value? But according to the spec this shouldn't be a problem. So what is actually the problem here and how can i request boosted fields with more than 10 documents?
Used SOLR version: 4.10.4
I found a documentation stating: "If absolute ordering is desired, a very high boost may be used."
And indeed, if I assign very highly spread boost values (e.g. 1000, 900, 80, 7), the sort order is correct.
But I guess it's open for discussion, whether this is a good practice and should be done like this. Seems a bit like guessing and using SOLR for something it was not designed for.
https://cwiki.apache.org/confluence/display/solr/SolrRelevancyCookbook#SolrRelevancyCookbook-BoostingRankingTerms
Related
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 would like to implement relevance feedback in Solr. Solr already has a More Like This feature: Given a single document, return a set of similar documents ranked by similarity to the single input document. Is it possible to configure Solr's More Like This feature to behave like More Like Those? In other words: Given a set of documents, return a list of documents similar to the input set (ranked by similarity).
According to the answer to this question turning Solr's More Like This into More Like Those can be done in the following way:
Take the url of the result set of the query returning the specified documents. For example, the url http://solrServer:8983/solr/select?q=id:1%20id:2%20id:3 returns the response to the query id:1 id:2 id:3 which is practically the concatenation of documents 1, 2, 3.
Put the above url (concatenation of the specified documents) in the url.stream GET parameter of the More Like This handler: http://solrServer:8983/solr/mlt?mlt.fl=text&mlt.mintf=0&stream.url=http://solrServer:8983/solr/select%3Fq=id:1%20id:2%20id:3. Now the More Like This handler treats the concatenation of documents 1, 2 and 3 as a single input document and returns a ranked set of documents similar to the concatenation.
This is a pretty bad implementation: Treating the set of input documents like one big document discriminates against short documents because short documents occupy a small portion of the entire big document.
Solr's More Like This feature is implemented by a variation of The Rocchio Algorithm: It takes the top 20 terms of the (single) input document (the terms with the highest TF-IDF values) and uses those terms as the modified query, boosted according to their TF-IDF. I am looking for a way to configure Solr's More Like This feature to take multiple documents as its input, extract the top n terms from each input document and query the index with those terms boosted according to their TF-IDF.
Is it possible to configure More Like This to behave that way? If not, what is the best way to implement relevance feedback in Solr?
Unfortunately, it is not possible to configure the MLT handler that way.
One way to do it would be to implement a custom SearchComponent and register it to a (dedicated) SearchHadler.
I've already done something similar and it is quite easy if you look a the original implementation of MLT component.
The most difficult part is the synchronization of the results from different shard servers, but it can be skipped if you do not use shards.
I would also strongly recommend to use your own parameters in your implementation to prevent collisions with other components.
I am trying to query Solr with following requirement:
_ I would like to get all documents which not have a particular field
-exclusivity:[* TO *]
I would like to get all document which have this field and got the specific value
exclusivity:(None)
so when I am trying to query Solr 4 with:
fq=(-exclusivity:[* TO *]) OR exclusivity:(None)
I have only got results if the field exists in document and the value is None but results not contain results from first query !!
I cannot understand why it is not working
To explain your results, the query (-exclusivity:[* TO *]) will always get no results, because you haven't specified any result to retrieve. By default, Lucene doesn't retrieve any results, unless you tell it to get them. exclusivity:(None) isn't a limitation placed on the full result set, it is the key used to find the documents to retrieve. This differs from a database, which by default returns all records in a table, and allows you to limit the set.
(-exclusivity:[* TO *]) only specifies what NOT to get, but doesn't tell it to GET anything at all.
Solr has logic to handle Pure negative queries (I believe, in much the same way as below, by implicitly retrieving all documents first), but from what I gather, only as the top level query, and it does not handle queries like term1 OR -term2 documented here.
I believe with solr you should be able to use the query *:* to get all docs (though that would not be available in raw lucene), so you could use the query:
(*:* -exclusivity:[* TO *]) exclusivity:(None)
which would mean, get (all docs except those with a value in exclusivity) or docs where exclusivity = "None"
I have founded answer to this problem. I have made bad assumption how "-" works in solr.I though that
-exclusivity:[* TO *]
add everything without exclusivity field to the data set but it is not the case. The '-' could only exclude things from data set. BTW femtoRgon you are right but I am using it as fq (filter query) not as a master query I have forgotten to mention that.
So the solution is like
-exclusivity:([* TO *] AND -(None))
and full query looks like
/?q=*:*&fq=-exclusivity:([* TO *] AND -(None))
so that means I will get everything does not have field exclusivity or has this field and it is populated with value None.
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'm using SolrNet to access a Solr index where I have a multivalue field called "tags". I want to perform the following pseudo-code query:
(tags:stack)^10 OR (tags:over)^5 OR (tags:flow)^2
where the term "stack" is being boosted by 10, "over" is being boosted by 5 and "flow" is being boosted by 2. The result I'm after is that results with "stack" will appear higher than those with "flow", etc.
The problem I'm having is that say "flow" only appears in a couple of documents, but "stack" appears in loads, then due to a high idf value, documents with "flow" appear above those with "stack".
When this was project was implemented straight in Lucene, I used ConstantScoreQuery and these eliminated the idf based the score solely on the boost value.
How can this be achieved with Solr and SolrNet, where I'm effectivly just passing Solr a query string? If it can't, is there an alternative way I can approach this problem?
Thanks in advance!
Solr 5.1 and later has this built into the query parser syntax via the ^= operator.
So just take your original query:
(tags:stack)^10 OR (tags:over)^5 OR (tags:flow)^2
And replace the ^ with ^= to change from boosted to constant:
(tags:stack)^=10 OR (tags:over)^=5 OR (tags:flow)^=2
I don't think there any way to directly express a ConstantScoreQuery in Solr, but it seems that range and prefix queries use ConstantScoreQuery under the hood, so you could try faking a range query, e.g. tags:[flow TO flow]
Alternatively, you could implement your own Solr QueryParser.