Wildcard Analysis in simple_query_string Query

Elastic Stack Elasticsearch
1

Hello,

I wonder how ES analyzes wildcard in simple_query_string queries. Specifically, what happens when query string includes a stop word and asterisk (*).

In my case,

My index has a custom analyzer with a bunch of filters including stop word filter and a char filter. And I'm running a simple_query_string query by setting analyze_wildcard option to true and query string to (<a stop word>*). How does analyzer work in this case?

Notes:

  • I get no hits.
  • I get hits when analyze_wildcard is set to false. (i.e There are entries of which queried field value is starting with <a stop word> in query string.)
2

You can run your query with the explain parameter and you will see what the final query looked like, that may help getting down to your issue.

See https://www.elastic.co/guide/en/elasticsearch/reference/7.5/search-request-body.html#request-body-search-explain

3

In documentation, it says:

Enables explanation for each hit on how its score was computed.

It helped for analyze_wildcard = false case, that I get hits. But no good for my main question where analyze_wildcard option is set to true :frowning:

4

You can use the dedicated explain API for this.

5

Thanks for your help @spinscale :slight_smile:

I got what I want here. I just want to report that analysis of wildcard terms looks a little bit problematic, and analyze_wildcard is explained in an uncertain way in the documentation. Even, there is an open issue about it from 2016 :slight_smile:

6

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