lucene - In Elasticsearch, how do I search for an arbitrary substring?

Question

In Elasticsearch, how do I search for an arbitrary substring, perhaps including spaces? (Searching for part of a word isn't quite enough; I want to search any substring of an entire field.)

I imagine it has to be in a keyword field, rather than a text field.

Suppose I have only a few thousand documents in my Elasticsearch index, and I try:

  "query": {
         "wildcard" : { "description" : "*plan*" }
  }

That works as expected--I get every item where "plan" is in the description, even ones like "supplantation".

Now, I'd like to do

  "query": {
         "wildcard" : { "description" : "*plan is*" }
  }   

...so that I might match documents with "Kaplan isn't" among many other possibilities.

It seems this isn't possible with wildcard, match prefix, or any other query type I might see. How do I simply search on any substring? (In SQL, I would just do description LIKE '%plan is%')

(I am aware any such query would be slow or perhaps even impossible for large data sets.)

Answer 1

Have you tried the regxp query in elasticsearch? It sure does sound like something you might be interested in.