Multiple word queries on solr - solr

I am using solr 3.3.0 working out of the box using the example folder
solrQueryParser defaultOperator = "OR"
My problem is that Solr doesn't seem to be returning good results when I search for a multiple word phrase.
The following search return no results.
http://localhost:8080/solr/select/?q=roof+fixing
However, when I search for roof or fixing, they both return a few good results.
http://localhost:8080/solr/select/?q=roof returns 4 results
http://localhost:8080/solr/select/?q=fixing returns 3 results
On the query for "roof fixing", I expect solr to return 7 results. The 4 records for roof and 3 records for fixing.
Is any special configuration necessary for that to happen?

You just expressed your query incorrectly.
Try the following query from the Admin page:
(roof OR fixing)
Or, if you want to find that in a particular field:
fieldname:(roof OR fixing)
When you give SOLR a query like "roof fixing" you are effectively asking for all documents which have "roof" AND "fixing" in the default field (or the default dismax set of fields. The only way to change the meaning is to rewrite the query that your users type in. That's what we do, but on a larger scale. We have a front end interface that provides a whole bunch of options and generate a SOLR query from it. People can enter a search term in a specific field and if there is more than one word and it's not quoted, we add the AND. Then we OR together all of the fields that are filled in. Some fields are special and have a MIN and a MAX version which we turn into a range query :[0 TO 125000]. And there are some dropdowns that support multiple selections which we also turn into an OR, e.g. State:("WA" OR "CA" OR "OR" OR "NV")

Solr won't necessarily return 7 results for "roof OR fixing" as one result could include both "roof" and "fixing". Suppose "roof" has 3 results, "fixing" has 4, but both "roof" and "fixing" appear in 2 results. You will get only 5 results on a search for "roof OR fixing" as Solr will not return duplicate results.
Have you tried using a url-encoded space ("%20") instead of the "+" sign? If the default operator is OR you should not need to include that operator.

Related

Solr query string not working for full text searches

I'm following this tutorial on how to perform indexing on sample documents using Solr. The default collection is "gettingstarted" as shown. Now I'm trying to query it. There are 52 entries as shown:
However, when I replace the q argument with say electronics, it should return 14 results. However, I get nothing.
When I replace the query string q with cat:electronics, then I actually get the 14 results. But why is this the case? isn't q=word supposed to search for word wherever it appears?
No, it's not. Your assumption that:
isn't q=word supposed to search for word wherever it appears?
is wrong. If you're using word as your only query, and nothing more - you're searching for word in the default search field. It does not search all available fields in all available documents.
Also be aware that the default query parser assumes that your query is in the Lucene Query Syntax. To handle more "natural" querying, you can use the edismax query parser. This query parser supports the qf parameter that tells Solr which fields to search, instead of having to use the cat:electronics syntax. Your example would then be q=electronics&qf=cat.
In the example documents you've given, qf=series_t author name cat is probably a decent value to search all these fields for the given query. You can also append ^<weight> to a field name to give hits in the different fields different weights. qf=name^10 cat would give a hit in name ten times the weight of a hit in the cat field.

Solr negative boost

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

Solr - How do I get the number of documents for each field containing the search term within that field in Solr?

Imagine an index like the following:
id partno name description
1 1000.001 Apple iPod iPod by Apple
2 1000.123 Apple iPhone The iPhone
When the user searches for "Apple" both documents would be returned. Now I'd like to give the user the possibility to narrow down the results by limiting the search to one or more fields that have documents containing the term "Apple" within those fields.
So, ideally, the user would see something like this in the filter section of the ui after his first query:
Filter by field
name (2)
description (1)
When the user applies the filter for field "description", only documents which contain the term "Apple" within the field "description" would be returned. So the result set of that second request would be the iPod document only. For that I'd use a query like ?q=Apple&qf=description (I'm using the Extended DisMax Query Parser)
How can I accomplish that with Solr?
I already experimented with faceting, grouping and highlighting components, but did not really come to a decent solution to this.
[Update]
Just to make that clear again: The main problem here is to get the information needed for displaying the "Filter by field" section. This includes the names of the fields and the hits per field. Sending a second request with one of those filters applied already works.
Solr just plain Doesn't Do This. If you absolutely need it, I'd try it the multiple requests solution and benchmark it -- solr tends to be a lot faster than what people put in front of it, so an couple few requests might not be that big of a deal.
you could achieve this with two different search requests/queries:
name:apple -> 2 hits
description:apple -> 1 hit
EDIT:
You also could implement your own SearchComponent that executes multiple queries in the background and put it in the SearchHandler processing chain so you only will need a single query in the frontend.
if you want the term to be searched over the same fields every time, you have 2 options not breaking the "single query" requirement:
1) copyField: you group at index time all the fields that should match togheter. With just one copyfield your problem doesn't exist, if you need more than one, you're at the same spot.
2) you could filter the query each time dynamically adding the "fq" parameter at the end
http://<your_url_and_stuff>/?q=Apple&fq=name:Apple ...
this works if you'll be searching always on the same two fields (or you can setup them before querying) otherwise you'll always need at least a second query
Since i said "you have 2 options" but you actually have 3 (and i rushed my answer), here's the third:
3) the dismax plugin described by them like this:
The DisMaxQParserPlugin is designed to process simple user entered phrases
(without heavy syntax) and search for the individual words across several fields
using different weighting (boosts) based on the significance of each field.
so, if you can use it, you may want to give it a look and start from the qf parameters (that is what the option number 2 wanted to be about, but i changed it in favor of fq... don't ask me why...)
SolrFaceting should solve your problem.
Have a look at the Examples.
This can be achieved with Solr faceting, but it's not neat. For example, I can issue this query:
/select?q=*:*&rows=0&facet=true&facet.query=title:donkey&facet.query=text:donkey&wt=json
to find the number of documents containing donkey in the title and text fields. I may get this response:
{
"responseHeader":{"status":0,"QTime":1,"params":{"facet":"true","facet.query":["title:donkey","text:donkey"],"q":"*:*","wt":"json","rows":"0"}},
"response":{"numFound":3365840,"start":0,"docs":[]},
"facet_counts":{
"facet_queries":{
"title:donkey":127,
"text:donkey":4108
},
"facet_fields":{},
"facet_dates":{},
"facet_ranges":{}
}
}
Since you also want the documents back for the field-disjunctive query, something like the following works:
/select?q=donkey&defType=edismax&qf=text+titlle&rows=10&facet=true&facet.query=title:donkey&facet.query=text:donkey&wt=json

Solr Index appears to be valid - but returns no results

Solr newbie here.
I have created a Solr index and write a whole bunch of docs into it. I can see
from the Solr admin page that the docs exist and the schema is fine as well.
But when I perform a search using a test keyword I do not get any results back.
On entering * : *
into the query (in Solr admin page) I get all the results.
However, when I enter any other query (e.g. a term or phrase) I get no results.
I have verified that the field being queried is Indexed and contains the values I am searching for.
So I am confused what I am doing wrong.
Probably you don't have a <defaultSearchField> correctly set up. See this question.
Another possibility: your field is of type string instead of text. String fields, in contrast to text fields, are not analyzed, but stored and indexed verbatim.
I had the same issue with a new setup of Solr 8. The accepted answer is not valid anymore, because the <defaultSearchField> configuration will be deprecated.
As I found no answer to why Solr does not return results from any fields despite being indexed, I consulted the query documentation. What I found is the DisMax query parser:
The DisMax query parser is designed to process simple phrases (without complex syntax) entered by users and to search for individual terms across several fields using different weighting (boosts) based on the significance of each field. Additional options enable users to influence the score based on rules specific to each use case (independent of user input).
In contrast, the default Lucene parser only speaks about searching one field. So I gave DisMax a try and it worked very well!
Query example:
http://localhost:8983/solr/techproducts/select?defType=dismax&q=video
You can also specify which fields to search exactly to prevent unwanted side effects. Multiple fields are separated by spaces which translate to + in URLs:
http://localhost:8983/solr/techproducts/select?defType=dismax&q=video&qf=features+text
Last but not least, give the fields a weight:
http://localhost:8983/solr/techproducts/select?defType=dismax&q=video&qf=features^20.0+text^0.3
If you are using pysolr like I do, you can add those parameters to your search request like this:
results = solr.search('search term', **{
'defType': 'dismax',
'qf': 'features text'
})
In my case the problem was the format of the query. It seems that my setup, by default, was looking and an exact match to the entire value of the field. So, in order to get results if I was searching for the sit I had to query *sit*, i.e. use wildcards to get the expected result.
With solr 4, I had to solve this as per Mauricio's answer by defining type="text_en" to the field.
With solr 6, use text_general.

Solr query results using *

I want to provide for partial matching, so I am tacking on * to the end of search queries. What I've noticed is that a search query of gatorade will return 12 results whereas gatorade* returns 7. So * seems to be 1 or many as opposed to 0 or many ... how can I achieve this? Am I going about partial matching in Solr all wrong? Thanks.
First, I think Solr wildcards are better summarized by "0 or many" than "1 or many". I doubt that's the source of your problem. (For example, see the javadocs for WildcardQuery.)
Second, are you using stemming, because my first guess is that you're dealing with a stemming issue. Solr wildcards can behave kind of oddly with stemming. This is because wildcard expansion is based by searching through the list of terms stored in the inverted index; these terms are going to be in stemmed form (perhaps something like "gatorad"), rather than the words from the original source text (perhaps "gatorade" or "gatorades").
For example, suppose you have a stemmer that maps both "gatorade" and "gatorades" to the stem "gatorad". This means your inverted index will not contain either "gatorade" or "gatorades", only "gatorad". If you then issue the query gatorade*, Solr will walk the term index looking for all the stems beginning with "gatorade". But there are no such stems, so you won't get any matches. Similarly, if you searched gatorades*, Solr will look for all stems beginning with "gatorades". But there are no such stems, so you won't get any matches.
Third, for optimal help, I'd suggest posting some more information, in particular:
Some particular query URLs you are submitting to Solr
An excerpt from your schema.xml file. In particular, include A) the field elements for the fields you are having trouble with, and B) the field type definitions corresponding to those fields
so what I was looking for is to make the search term for 'gatorade' -> 'gatorade OR gatorade*' which will give me all the matches i'm looking for.
If you want a query to return all documents that match either a stemmed form of gatorade or words that begin with gatorade, you'll need to construct the query yourself: +(gatorade gatorade*). You could alternatively extend the SolrParser to do this, but that's more work.
Another alternative is to use NGrams and TokenFilterFactories, specifically the EdgeNGramFilterFactory. .
This will create indexes for ngrams or parts of words. Documents, with a min ngram size of 5 and max ngram size of 8, would index: Docum Docume Document Documents
There is a bit of a tradeoff for index size and time. One of the Solr books quotes as a rough guide: Indexing takes 10 times longer Uses 5 times more disk space Creates 6 times more distinct terms.
However, the EdgeNGram will do better than that.
You do need to make sure that you don't submit wildcard character in your queries. As you aren't doing a wildcard search, you are matching a search term on ngrams(parts of words).
My guess is the missing matches are "Gatorade" (with a capital 'G'), and you have a lowercase filter on your field. The idea is that you have filters in your schema.xml that preprocess the input data, but wildcard queries do not use them;
see this about how Solr deals with wildcard queries:
http://solr.pl/en/2010/12/20/wildcard-queries-and-how-solr-handles-them/
("Solr and wildcard handling").
From what I've read the wildcards only matched words with additional characters after the search term. "Gatorade*" would match Gatorades but not Gatorade itself. It appears there's been an update to Solr in version 3.6 that takes this into account by using the 'multiterm' field type instead of the 'text' field.
A better description is here:
http://bensch.be/the-solr-wildcard-problem-and-multiterm-solution

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