Phrase suggestions (did you mean) in Elasticsearch

Introduction

Phrase suggestions help users find the right words when they make typos or spelling mistakes. They show a "Did you mean" message to guide users to the correct search terms.

When users type search queries with spelling errors.

To improve search results by suggesting correct phrases.

When you want to help users find what they mean even if they mistype.

To make search more friendly and reduce frustration.

When you want to suggest alternative phrases based on your data.

Syntax

Elasticsearch

{
  "suggest": {
    "text": "user input phrase",
    "phrase_suggestion_name": {
      "phrase": {
        "field": "field_name",
        "size": 1,
        "gram_size": 2
      }
    }
  }
}

Replace user input phrase with the text you want to check.

field_name is the field in your index to check for phrase suggestions.

Examples

This example suggests corrections for the phrase "quik brown fox" using the content field.

Elasticsearch

{
  "suggest": {
    "text": "quik brown fox",
    "simple_phrase": {
      "phrase": {
        "field": "content"
      }
    }
  }
}

This example suggests up to 2 phrase corrections for "helo wrld" using 3-word groups from the title field.

Elasticsearch

{
  "suggest": {
    "text": "helo wrld",
    "phrase_suggestion": {
      "phrase": {
        "field": "title",
        "size": 2,
        "gram_size": 3
      }
    }
  }
}

Sample Program

This request asks Elasticsearch to suggest corrections for the phrase "appl pie recip" in the recipe_text field of the my_index index.

Elasticsearch

POST /my_index/_search
{
  "suggest": {
    "text": "appl pie recip",
    "phrase_suggestion": {
      "phrase": {
        "field": "recipe_text",
        "size": 1,
        "gram_size": 2
      }
    }
  }
}

Important Notes

Phrase suggestions work best with well-indexed text fields.

You can adjust size to get more or fewer suggestions.

gram_size controls how many words are checked together for better phrase matching.

Summary

Phrase suggestions help fix typos in search queries.

Use the suggest part of the search request with phrase type.

Adjust field, size, and gram_size to control suggestions.

Practice

1. What is the main purpose of phrase suggestions (did you mean) in Elasticsearch?

easy

A. To help fix typos and suggest correct phrases in search queries

B. To sort search results by relevance

C. To filter documents based on date ranges

D. To aggregate numeric data for analytics

Solution

1. Step 1: Understand phrase suggestions purpose

   Phrase suggestions are designed to detect and correct typos or mistakes in user search queries.

2. Step 2: Compare with other features

   Sorting, filtering, and aggregations serve different purposes unrelated to typo correction.

3. Final Answer:

   To help fix typos and suggest correct phrases in search queries -> Option A

4. Quick Check:

   Phrase suggestions = typo correction [OK]

Hint: Phrase suggestions fix typos in queries [OK]

Common Mistakes:

• Confusing phrase suggestions with sorting or filtering
• Thinking phrase suggestions aggregate data
• Assuming phrase suggestions change document content

2. Which of the following is the correct way to specify a phrase suggestion in an Elasticsearch query?

easy

A. "suggest": {"my-suggestion": {"completion": {"field": "content"}}}

B. "suggest": {"my-suggestion": {"term": {"field": "content"}}}

C. "suggest": {"my-suggestion": {"text": "exampl", "phrase": {"field": "content"}}}

D. "suggest": {"my-suggestion": {"match": {"field": "content"}}}

Solution

1. Step 1: Identify phrase suggestion syntax

   Phrase suggestions use the "phrase" type inside the suggest block with a specified field.

2. Step 2: Check other options

   Options A, B, and D use other suggestion types like completion, term, or match, which are not phrase suggestions.

3. Final Answer:

   "suggest": {"my-suggestion": {"text": "exampl", "phrase": {"field": "content"}}} -> Option C

4. Quick Check:

   Phrase suggestion uses "phrase" type [OK]

Hint: Phrase suggestions use "phrase" type in suggest [OK]

Common Mistakes:

• Using term or completion instead of phrase
• Omitting the "field" inside phrase
• Misplacing the "text" parameter

3. Given this Elasticsearch phrase suggestion snippet, what will be the size of suggestions returned?

{
  "suggest": {
    "text": "quik brown",
    "phrase": {
      "field": "body",
      "size": 3
    }
  }
}

medium

A. 1 suggestion

B. Unlimited suggestions

C. 5 suggestions

D. 3 suggestions

Solution

1. Step 1: Identify the size parameter

   The "size" parameter inside the phrase suggestion controls how many suggestions are returned.

2. Step 2: Check the value of size

   Here, "size" is set to 3, so Elasticsearch will return up to 3 suggestions.

3. Final Answer:

   3 suggestions -> Option D

4. Quick Check:

   Size = 3 means 3 suggestions [OK]

Hint: Check "size" to know number of suggestions [OK]

Common Mistakes:

• Assuming default size without checking parameter
• Confusing size with gram_size
• Thinking size limits characters, not suggestions

4. Identify the error in this phrase suggestion query:

{
  "suggest": {
    "my-suggest": {
      "text": "helo world",
      "phrase": {
        "field": "content",
        "gram_size": "two"
      }
    }
  }
}

medium

A. "gram_size" should be an integer, not a string

B. "text" parameter is missing

C. "field" should be an array, not a string

D. Phrase suggestions don't support 'gram_size' parameter

Solution

1. Step 1: Check the "gram_size" parameter type

   "gram_size" expects an integer value, but here it is given as a string "two".

2. Step 2: Verify other parameters

   "text" and "field" are correctly specified; phrase suggestions do support "gram_size".

3. Final Answer:

   "gram_size" should be an integer, not a string -> Option A

4. Quick Check:

   gram_size = integer, not string [OK]

Hint: Use numbers, not words, for gram_size [OK]

Common Mistakes:

• Passing gram_size as a string
• Removing the text parameter
• Changing field to an array unnecessarily

5. You want to suggest corrections for a user query with multiple words and control the phrase suggestion to consider 2-gram phrases. Which of the following is the correct way to configure the phrase suggestion in Elasticsearch?

hard

A. { "suggest": { "text": "spel cheker", "phrase": { "field": "text", "gram_size": 2, "size": 2 } } }

B. { "suggest": { "my-suggest": { "text": "spel cheker", "phrase": { "field": "text", "gram_size": 2, "size": 2 } } } }

C. { "suggest": { "my-suggest": { "text": "spel cheker", "term": { "field": "text", "gram_size": 2 } } } }

D. { "suggest": { "my-suggest": { "text": "spel cheker", "phrase": { "field": "text", "gram_size": "2", "size": 2 } } } }

Solution

1. Step 1: Check the suggest block structure

   The suggest block must have a named suggestion (e.g., "my-suggest") containing "text" and "phrase" parameters.

2. Step 2: Verify phrase suggestion parameters

   "gram_size" should be an integer (2), and "size" controls number of suggestions. { "suggest": { "my-suggest": { "text": "spel cheker", "phrase": { "field": "text", "gram_size": 2, "size": 2 } } } } correctly uses these.

3. Step 3: Eliminate incorrect options

   { "suggest": { "text": "spel cheker", "phrase": { "field": "text", "gram_size": 2, "size": 2 } } } misses the named suggestion key. { "suggest": { "my-suggest": { "text": "spel cheker", "term": { "field": "text", "gram_size": 2 } } } } uses "term" instead of "phrase". { "suggest": { "my-suggest": { "text": "spel cheker", "phrase": { "field": "text", "gram_size": "2", "size": 2 } } } } passes "gram_size" as a string, which is invalid.

4. Final Answer:

   { "suggest": { "my-suggest": { "text": "spel cheker", "phrase": { "field": "text", "gram_size": 2, "size": 2 } } } } -> Option B

5. Quick Check:

   Named suggest + phrase + integer gram_size = correct [OK]

Hint: Use named suggest with phrase and integer gram_size [OK]

Common Mistakes:

• Omitting the named suggestion key
• Using term instead of phrase
• Passing gram_size as a string