Is match query case sensitive in elasticsearch?

Question

I have followed an example from here

The mapping for the index is

{
  "mappings": {
    "my_type": {
      "properties": {
        "full_text": {
          "type":  "string" 
        },
        "exact_value": {
          "type":  "string",
          "index": "not_analyzed" 
        }
      }
    }
  }
}

And the document indexed is

{
  "full_text":   "Quick Foxes!", 
  "exact_value": "Quick Foxes!"  
}

I have noticed while using a simple match query on the "full_text" field like below

{
  "query": {
    "match": {
      "full_text": "quick"
    }
  }
}

I get to see the document is matching. Also if I use uppercase, that is "QUICK" , as the search term, it shows the document is matching.

Why is it so?. By default the tokenizer would have splitted the text in "full_text" field in to "quick","foxes". So how is match query matching the document for upper cased values?

Answer 1

Because you haven't specified which analyzer to use for "full_text" field into your index mapping then the default analyzer is used. The default will be "Standard Analyzer".

Quote from ElasticSearch docs:

An analyzer of type standard is built using the Standard Tokenizer with the Standard Token Filter, Lower Case Token Filter, and Stop Token Filter.

Before executing the query in your index, ElasticSearch will apply the same analyzer configured for your field to your query values. Because the default analyzer uses Lower Case Token Filter in its processing then using "Quick" or "QUICK" or "quick" will give you to the same query because the analyzer will lower case them by using the Lower Case Token Filter and result to just "quick".