Highlighting matched text in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of highlighting in Elasticsearch search results?

Highlighting shows the parts of the text that match the search query, making it easier to see why a document was found.

beginner

Which Elasticsearch query section is used to add highlighting to search results?

The highlight section is added alongside the query in the search request to specify which fields to highlight.

intermediate

What does the pre_tags and post_tags in Elasticsearch highlighting do?

They define the HTML or text tags that wrap around the matched text to visually mark it, for example, <em> and </em>.

beginner

How do you specify which fields to highlight in an Elasticsearch query?

Inside the highlight section, use the fields object with field names as keys and empty objects or options as values.

intermediate

What is the default behavior if you do not specify pre_tags and post_tags in Elasticsearch highlighting?

Elasticsearch wraps matched text with <em> and </em> tags by default.

In Elasticsearch, where do you add the highlighting instructions in a search request?

A Inside the <code>highlight</code> section alongside the <code>query</code>

B Inside the <code>filter</code> section

C Inside the <code>sort</code> section

D Inside the <code>aggs</code> section

Highlighting is specified in the highlight section, which is part of the search request body.

What tags does Elasticsearch use by default to wrap highlighted text?

A <code>&lt;strong&gt;</code> and <code>&lt;/strong&gt;</code>

B <code>&lt;mark&gt;</code> and <code>&lt;/mark&gt;</code>

C <code>&lt;highlight&gt;</code> and <code>&lt;/highlight&gt;</code>

D <code>&lt;em&gt;</code> and <code>&lt;/em&gt;</code>

By default, Elasticsearch wraps matched text with <em> and </em> tags.

How do you specify multiple fields to highlight in Elasticsearch?

A List them as an array under <code>fields</code>

B Use a comma-separated string in <code>fields</code>

C Add each field as a key inside <code>fields</code> with an empty object as value

D Highlighting only works on one field at a time

You add each field as a key inside the fields object with an empty object or options as the value.

What is the effect of setting number_of_fragments to 0 in highlighting?

A No fragments are returned

B The whole field content is returned as one fragment

C Only the first fragment is returned

D Fragments are returned with default size

Setting number_of_fragments to 0 returns the entire field content as a single highlighted fragment.

Which of these is NOT a valid use of the highlight section in Elasticsearch?

A Sort search results by relevance

B Customize tags wrapping matched text

C Control fragment size and number

D Specify fields to highlight

Sorting is controlled by the sort section, not by highlight.

Explain how to add highlighting to an Elasticsearch search query and customize the tags used to mark matched text.

Think about where you put the highlight instructions and how to change the default <em> tags.

Describe the default behavior of Elasticsearch highlighting and how it helps users understand search results.

Focus on what the user sees and why highlighting is useful.