I am creating a schema for Vespa mainly for English, but with two fields in Wylie transliteration of Tibetan, which looks like this
'jam dpal smra ba'i seng ge la bstod pa ut+pal dmar po'i do shal
Typically users want to match every token and preserve the word order, and preferably in the beginning of the field.
For example, to find the field above, user might enter "'jam dpal smra ba'i seng ge". They would not appreciate results where these tokens would appear in different order, even if that would rank high with BM25. BM25 would still be needed for fallback.
Could you give me an example of the schema field / ranking expression to rank in this order:
exact match in the beginning of field
exact match anywhere
bm25
Naturally, I'll turn off stemming. Also, apostrophes and, less importantly, plus signs should be preserved.
I have read especially the Schema Reference of Vespa docs, but I did not find a solution.
I got the best results with
field wylie type string {
indexing: index | summary
index: enable-bm25
stemming: none
}
rank-profile native_rank_and_wylie {
first-phase {
expression: nativeRank(title, body) + fieldMatch(wylie).earliness + fieldMatch(wylie).longestSequence * 0.4
}
}
Note that longestSequence is not normalized and can affect scores a lot.
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
Suppose a user enters a two word input for search, since the default boolean applied is OR, all entries containing all or both entries appear.
What I was interested to know, is that if conditions specifically meeting the AND condition could be boosted.
In case of multiple words, can words be specified to imply specific constraints in searching or boost few parameters in case these words are present.For e.g: , if input be "with x and y without z", can i make my solr to interpret it as (x AND y) AND (Not z)? or at least boost those entries which partially or fully meet the requirement?
EDIT:
I have tried using boost with edismax as shown here:
$query = $client->createSelect(); //create search query
$query->setQuery('memberType:'.$searchQuery.' firstName:'.$searchQuery.' gender:'.$searchQuery); //include fields required for searching //meantion fields to be searched and search query/ies
$edismax = $query->getEDisMax();
$edismax->setQueryFields('firstName memberType^3 gender^2'); //boost fields
$query->setStart($start)->setRows($rows); //vary bracketted numbers to vary results staring point and no. of rows to be displayed, use variables instead of constants
$query->setFields(array('id', 'firstName', 'lastName', 'eid', 'gender', 'memberType')); //set return fields
//$query->addSort('id', $query::SORT_ASC); //sort field and customisations
$resultSet = $client->select($query);
When i search for a name with a particular member type, like "sanjay candidate" i expect the order to be entries with sanjay and candidate, and then all users who are candidates and then all users who are sanjay, but instead i get sanjay and candidate then all who are sanjay and then all candidates.
I am not able to figure out what the issue may be or if i can provide a more customized boosting.
If you are using eDismax, you have a whole collection of boosting options for a phrase, bigram, a separate boosting query and so on. Reading through the wiki page and experiment. You should not need to do any custom coding for this scenario.
Hello stackOverflowers
I have a field in a Solr document collection with a field called
names_txt - this is a multiValue="true" field.
This field contains all the names of the associated persons to a document
I want to be able to both do a fuzzy search and at the same time limit the number of terms between the to matching terms.
The query
names_txt:("markus foss"~2)
Will return all documents where you find the terms markus and foss where theres max 2 terms between them.
But when i search in a fuzzy way AND want to also specify the max number of terms between the matches, I cant get the syntax right.
The query:
names_txt:(markus~0.7 foss~0.7)
This does work, but returns false postives, since it will return a document with "markus something" in one value, and "foss somethingElse" in another.
What I would like to write is:
(markus~0.7 foss~0.7)~2
but this syntax is illegal in solr.
Anyone out there have a solution for my problem?
Since in one single query term Solr can either process a word distance restraint or a fuzzy search restraint, we will need two terms for this:
names_txt:("markus foss"~2) AND names_txt:(markus~0.7 foss~0.7)
Note that quantifying fuzzyness by a float number is deprecated. Internally, lucene converts converts the float number to an int between 0 and 2 anyway, so we should use this integer (Damereau Levenshtein) edit distance right from the beginning in our search terms. So my final proposal states:
names_txt:("markus foss"~2) AND names_txt:(markus~1 foss~1)
(For those who are interested: The deprecated, somewhat quirky function that converts the similarity float to an edit distance int can be found at the end of this code file.)
I think you could do that using SpanQuery The issue is that the usual query parsers in Solr dont support them. Look at this article that mentions those that support spans: Surround, Xml-Query-Parser and Qsol. But check the status of each in current solr version.
Problem Description
I'm trying to implement a custom algorithm to match user provided free-text input, a company name such as "Ford Motor", against a reference data source consisting of 1.4 million company names.
The algorithm executes following steps:
Step 1) Performs an "Exact Match", followed by "Begins Match" and finally "Contains Match" of user provided search input. Results from this step are also sorted in the same order.
Step 2) Performs a token by token match of search input with reference company name.
Every token is matched in following order: Exact, Begins, Contains, Levenshtein Distance (< 0.2) and Refined Soundex.
E.g. If user input is "Foord Motur Holding" and it's being matched against "The Ford Motor Holdings Company" then first token "Foord" will match "Ford" based on Soundex match, second token "Motur" will match "Motor" based on Edit Distance Algo and and last token "Holding" will match "Holdings" via Begins match.
Scoring:
Every token match is first scored on a scale that rates the matching technique, with Exact match being the best and Soundex being the worst.
The overall score is calculated, on a scale of 0-100%, by calculating a weighted average of individual token-match scores. Weights are assigned based on index-order of token i.e. the first token has highest weight and last token has lowest.
My Partial Solution
I have implemented a simple schema in solr to store referance company names. A String field (called companyName), a simple text field (called as companyText) copied from string and another text field (called as companySoundex) copied from string and using PhoneticFilterFactory for Refined Soundex based matching.
I have been able to replicate step 1) in a single solr query.
For step 2) I plan to fire 3 parallel queries to solr server. First query performing a simple text search on companyText field, second query performing fuzzy match using ~ operator on companyText field and third query performing soundex match on companySoundex field. I plan to somehow combine the results from these 3 parallel queries to get desired final result.
Questions:
1) Is there a better way to replicate Step 2) of original algorithm?
2) Even if I go with my "three-parallel-queries" approach then how to get the "right" sorting order as I get in the original algorithm ?
I guess the main problem is how to compare the solr scores from these 3 entirely different queries to do the final combining of results
Thanks for reading this long question. Any help/pointers would be greatly appreciated.
Look at the DisMax query parser. http://wiki.apache.org/solr/DisMaxRequestHandler
For each separate query, you'll actually build up separate fields in the index for matching. Then use DisMax to combine the queries in a weighted fashion.
I suggest giving up on your 3 parallel queries approach now. Last time I looked into this it was impossible to relate scores from 2 separate queries. It just doesn't work. If you want a single set of results sorted by score, you have to figure out how to do this in a single query.
IMHO, This functionality can not be achieved in out of the box handlers that Solr provides. You should be better with writing a custom query handler that handles and scores the results in this manner.
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