Phrase suggestions (did you mean) in Elasticsearch - Step-by-Step Execution

Concept Flow - Phrase suggestions (did you mean)

User types query

↓

Elasticsearch receives query

↓

Check for spelling errors

↓

Generate phrase suggestions

↓

Return suggestions to user

↓

User selects suggestion or original query

The flow shows how Elasticsearch takes a user query, checks for possible spelling mistakes, generates phrase suggestions, and returns them for user selection.

Execution Sample

Elasticsearch

POST /_search
{
  "suggest": {
    "text": "quik brown fox",
    "phrase_suggest": {
      "phrase": {"field": "content"}
    }
  }
}

This query asks Elasticsearch to suggest corrections for the phrase 'quik brown fox' based on the 'content' field.

Execution Table

Step	Action	Input	Output	Notes
1	Receive query	"quik brown fox"	Query accepted	User input received
2	Analyze phrase	"quik brown fox"	Tokens: [quik, brown, fox]	Split phrase into words
3	Check spelling	quik	Suggest: quick	Detected possible typo
4	Check spelling	brown	No suggestion	Word is correct
5	Check spelling	fox	No suggestion	Word is correct
6	Generate phrase suggestion	[quick, brown, fox]	Suggested phrase: quick brown fox	Phrase suggestion created
7	Return suggestions	Suggested phrase	Response with suggestion	Sent back to user

💡 All tokens checked; suggestions generated and returned

Variable Tracker

Variable	Start	After Step 2	After Step 6	Final
query_text	"quik brown fox"	"quik brown fox"	"quick brown fox"	"quick brown fox"
tokens	[]	[quik, brown, fox]	[quick, brown, fox]	[quick, brown, fox]
suggestions	[]	[]	[quick]	[quick]

Key Moments - 2 Insights

Why does Elasticsearch suggest 'quick' instead of 'quik'?

Because in step 3 of the execution_table, Elasticsearch detects 'quik' as a misspelled word and suggests 'quick' based on its dictionary and frequency.

Why are 'brown' and 'fox' not changed in the suggestion?

As shown in steps 4 and 5, these words are recognized as correct, so no suggestions are made for them.

Visual Quiz - 3 Questions

Look at the execution_table, what is the suggested correction for 'quik'?

A quit

B quik

C quick

D quiz

💡 Hint

See step 3 in the execution_table where spelling is checked for 'quik'.

At which step does Elasticsearch split the phrase into tokens?

A Step 1

B Step 2

C Step 4

D Step 6

💡 Hint

Check the action column in the execution_table for tokenization.

If the input phrase was 'quik brwn fox', what would change in the variable_tracker?

A Suggestions would include corrections for both 'quik' and 'brwn'.

B Only 'quik' would have a suggestion.

C No suggestions would be made.

D The tokens would not change.

💡 Hint

Consider how multiple misspelled words are handled as shown in the variable_tracker and execution_table.

Concept Snapshot

Phrase suggestions help fix typos in user queries.
Elasticsearch splits the phrase into words.
Each word is checked for spelling errors.
Suggestions are generated for misspelled words.
The corrected phrase is returned to the user.
Use the 'phrase' suggester in the query.

Full Transcript

This visual execution shows how Elasticsearch processes a phrase suggestion query. The user inputs a phrase with a typo, 'quik brown fox'. Elasticsearch receives the query and splits it into tokens: 'quik', 'brown', and 'fox'. It checks each word for spelling errors. It finds 'quik' is misspelled and suggests 'quick'. The other words are correct. Elasticsearch then generates the phrase suggestion 'quick brown fox' and returns it to the user. Variables like query_text, tokens, and suggestions update step-by-step. Key moments include understanding why only 'quik' is corrected and how tokenization works. The quiz tests knowledge of these steps. This helps beginners see how phrase suggestions work internally.

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