ElasticSearch incorrectly indexing and querying on non-alphanumeric characters - string

My ElasticSearch index is not correctly indexing and querying non-alphanumeric characters. Specifically, dots and dashes are causing problems.
If I index a document with the name "O.K. Corral," it should match queries for "OK Corral". Similarly, if I index "Whiskey A Go-Go," I'd like it to match "Whiskey A GoGo" and "Whiskey A Go Go".
Right now, only queries with the correct dots and dashes will return these documents.
I'm hoping the solution will also solve any potential problems with other non-alphanumeric characters, like commas and apostrophes.
It sounds like a job for ElasticSearch token filters, but I haven't been able to find one that does what I'm looking for. Also, I would like to do this within ElasticSearch -- I don't want to write custom string manipulations to normalize data before it gets to my ES index.
Thanks for your help!

You might want to have a look at the Word Delimiter Token Filter. It will at least do what you want with "Whiskey A GoGo" and "Whiskey A Go-Go,". You can check its behaviour in advance using the analyze api.

Related

Using ArangoSearch LIKE to search for a string with space

I created an ArangoSearch view over a collection and am using the SEARCH keyword with wildcards w/ LIKE to search a field with spaces, similarly to how MySQL would. The problem I am running in to is, I keep getting an empty set even though records with the Star Wars title definitely exist.
Note, searching for '%star%' works and returns results... as soon as I add a space and search for '%star wars%' the query returns empty set.
This is the query
FOR d IN imdb_norm
SEARCH ANALYZER(d.name LIKE "%Star Wars%", "text_en")
RETURN d.name
This is the structure, running arango version 3.7.2
The thing is since you're using text_en, it breaks up strings into individual words Since all spaces are considered as break characters, there is not a single term (a word stored in aragnosearch index) containing a whitespace.
If you don't need tokenization, please can consider indexing a word as it is (i.e. without case conversion, accent removal, etc) using identity analyzer, or check out norm analyzer instead.
https://www.arangodb.com/docs/stable/arangosearch-analyzers.html#analyzer-types

Azure Search - regex search

I am trying to configure Azure Search to find some strings that have special characters, for example
ABC*DEF
When I look for a the full term using "ABC*DEF", it works perfectly.
The problem comes if I want to use a regex term:
When I use a partial term, like /(.*)ABC(.*)/, the result has no problem
When I use a partial term, like /(.*)DEF(.*)/, the result has no problem
But when I try to look for something like /(.*)C\*D(.*)/, the result is empty.
I am using a standard analyzer. I tried also the keyword analyzer but that way the regex search doesn't work at all.
Any suggestions?
You won't be able to create a regex expression that matches ABC*DEF using the standard analyzer.
If you run "ABC\*DEF" through the analyzer api using "standard" analyzer, you will see that ABC*DEF gets divided into 2 tokens at indexing time -> "ABC" and "DEF". Regex expression are not analyzed, however, they need to match a token that exist in the index.
Since ABC\*DEF does not exist in the index (only "ABC" and "DEF" exist), you won't be able to find it using the expression you are searching for.
Using the "keyword" analyzer will keep the whole field as a single token, so if the field "only" contained the expression ABC\*DEF, then the regex expression would work on it, however, if ABC\*DEF is part of a larger paragraph of text, then that's probably not what you want to use.
Your best bet is to create a custom analyzer that tokenizes your text in the way that preserves the special characters that are relevant to your use case.
If you're searching for special chars, why don't you discard normal chars?
[^\w]

Can someone help me understand Solr search behaviour in this case?

Query is this :- (Profisee)
Indexed Field has the exact same token as in the above input query. But Solr search is giving zero results.
If Query is this :- (Profisee
Then I am able to find the document in the result.
P.S: I am able to get the document result for (Pro, (Profi, (Profise etc queries also.
Here are the attached images.
Exact Query No Result
Inexact Query Got Result
Here is my schema.xml definition for the fieldtype
First, please include the relevant details in your question next time, as images are hard to search, makes it hard to get the overview of your question and is hard to read for those that doesn't have perfect vision.
For your actual question, the problem is that you have a WhitespaceTokenizer. This will only break words on whitespace, such as . The indexed document contains your term as (foo), which means that only (foo) will match (since the tokenizer only breaks on whitespace, and ( or ) isn't whitespace).
foo (bar) will be indexed as two tokens, foo and (bar). Searching for (bar will match neither.
Use the StandardTokenizer to get the behaviour you want, or use a WordDelimiterGraphFilterFactory to break the word into further tokens.

Required number of characters in azure search

I've made an azure search service and it's up and working. I would like for users to be able to search with 3 characters or more.
I have the following texts in different documents:
Paracet 200mg
Paracet 150mg
Kodein/paracetamol SA
When I search for 'par' I get no results. I have to type 5 characters (parac) and I get 1 & 2 as a result. I want this result for 'par' as well. Is this possible? I can't find anything in the documentation on setting the required number of characters for a search.
For the best performance, you could enable the "fast" prefix analyzer in your index, which will break down every token into a list of prefixes at indexing time. Here's some additional information on how to do that : https://azure.microsoft.com/en-us/blog/custom-analyzers-in-azure-search/
This would require you to re-index your data, so if you are creating a brand new index, this is an option.
If re-indexing is not an option, you can instead use the suffix operation '*' in your query. Here's more information on the suffix operator : https://learn.microsoft.com/en-us/rest/api/searchservice/Simple-query-syntax-in-Azure-Search?redirectedfrom=MSDN
I suspect searching using the suffix operator (or re-indexing while using fast prefix analyzer) will also work with the 3rd document you listed (Kodein/paracetamol SA). If it still does not work, it might be due to you using a tokenizer that does not split on the '/' character. The default analyzer should correctly split on '/', but if you are using a custom analyzer it's possible the whole "Kodein/paracetamol" expression get tokenized into a single term, which would explain why a search for parace* does not return the document, since the prefix of the document is "kodeā€¦".

Solr exact search with a hyphen

I am trying to search for a term in Solr in the Title that contains only the string 1604-04. But the results come back with anything that contains 1604 or 04. What would the syntax be to force solr to search on the exact string of 1604-04?
You can also use Classic Tokenizer.The Classic Tokenizer preserves the same behavior as the Standard Tokenizer with the following exceptions:-
Words are split at hyphens, unless there is a number in the word, in which case the token is not split and
the numbers and hyphen(s) are preserved.
This means if someone searches for 1604-04 then this Tokenizer won't break search string into two tokens.
If you want exact matches only, use a string field or a text field with a KeywordTokenizer as the tokenizer. These will keep your tokens intact as one single entry, and won't break it up into multiple tokens.
The difference is that if you use a Textfield with a KeywordTokenizer, you can still apply other filters, such as a LowercaseFilter, while a string field will store anything verbatim without any further processing possible.
Your analyzer is splitting "1604-04" into two terms, "1604" and "04". You've received answer on how to change your analysis to stop doing that.
Changing your analysis my not be the best solution (can't be entirely sure based on what you've written). Using a phrase query would be the usual way to do this. You can use a phrase query by wrapping it in quotes:
field:"1604-04"
This will still analyze and split it into two terms, but it will look for those terms in sequence. So, that query would match "1604-04" and "1604 04", but not "1604 some other stuff 04".

Resources