Phrase suggestions (did you mean) in Elasticsearch - Mini Project: Build & Apply

Elasticsearch Phrase Suggestions (Did You Mean)

📖 Scenario: You are building a search feature for an online bookstore. Users often mistype book titles or author names. To improve user experience, you want to add a 'Did you mean?' phrase suggestion feature that helps correct their search queries.

🎯 Goal: Create an Elasticsearch phrase suggestion query that suggests corrections for misspelled search terms entered by users.

📋 What You'll Learn

Create an Elasticsearch index named books with a title field of type text.

Add a phrase suggestion query to suggest corrections for the title field.

Set the phrase suggestion to use the title field and provide a sample misspelled input.

Configure the phrase suggestion with max_errors set to 2 and size set to 1.

💡 Why This Matters

🌍 Real World

Phrase suggestions improve search experience by helping users find correct results even when they mistype queries.

💼 Career

Understanding phrase suggestions is useful for roles in search engineering, data engineering, and backend development working with Elasticsearch.

1

Create the Elasticsearch index books with a title field

Create an Elasticsearch index called books with a mapping that defines a title field of type text.

Elasticsearch

# Create the index with mapping for title field

Hint

Use the PUT /books API with a JSON body defining the mappings and properties.

2

Add a phrase suggestion query with misspelled input

Write a phrase suggestion query that suggests corrections for the title field using the misspelled text "harry poter".

Elasticsearch

{
  "mappings": {
    "properties": {
      "title": {
        "type": "text"
      }
    }
  }
}

{
  "suggest": {
    "text": "harry poter",
    "phrase_suggestion": {
      "phrase": {
        "field": "title"
      }
    }
  }
}
# Your code here

Hint

Use the suggest object with text and a named suggestion containing phrase and field.

3

Configure phrase suggestion with max_errors and size

Add max_errors set to 2 and size set to 1 inside the phrase object of the phrase suggestion query.

Elasticsearch

{
  "mappings": {
    "properties": {
      "title": {
        "type": "text"
      }
    }
  }
}

{
  "suggest": {
    "text": "harry poter",
    "phrase_suggestion": {
      "phrase": {
        "field": "title",
        "max_errors": 2,
        "size": 1
      }
    }
  }
}
# Your code here

Hint

Add max_errors and size inside the phrase object to control suggestion behavior.

4

Complete the phrase suggestion query for Elasticsearch

Ensure the full Elasticsearch phrase suggestion query includes the suggest object with text set to "harry poter", the phrase suggestion named phrase_suggestion, and the phrase object with field set to "title", max_errors set to 2, and size set to 1.

Elasticsearch

{
  "mappings": {
    "properties": {
      "title": {
        "type": "text"
      }
    }
  }
}

{
  "suggest": {
    "text": "harry poter",
    "phrase_suggestion": {
      "phrase": {
        "field": "title",
        "max_errors": 2,
        "size": 1
      }
    }
  }
}
# Your code here

Hint

Double-check the full phrase suggestion query structure matches the requirements.

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