What is escape property in query_string in elasticsearch

Question

I have a problem using wildcard in query_string in elasticsearch.I can not find documentation for the "escape" property in query_string when the value is "true" I got some results but when it is "false" the result is zero.

{
                    "query_string": {
                        "query": "*Serial\\+*",
                        "fields": [
                            "info.name^1.0"
                        ],
                        "type": "best_fields",
                        "allow_leading_wildcard": true,
                        "analyze_wildcard": true,
                        "escape": true,
                        "auto_generate_synonyms_phrase_query": true,
                        "fuzzy_transpositions": true,
                        "boost": 1.0
                    }
                }

can anybody explain the "escape" property?

Answer 1

Weird that its not documented, but looking at the source code we can see:

Es query string source code

If "escape" is "true", the code calls org.apache.lucene.queryparser.classic.QueryParser.escape

On the query string, the function itself is documented as

Returns a String where those characters that QueryParser expects to be escaped are escaped by a preceding \.

So looks like this flag is just used to automatically escape characters for you, so you don't have to manually escape them