Completion suggester in Elasticsearch - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a completion suggester in the search query.

Elasticsearch

{
  "suggest": {
    "song-suggest": {
      "prefix": "nirv",
      "completion": {
        "field": "[1]"
      }
    }
  }
}

Drag options to blanks, or click blank then click option'

Atitle

Btitle_suggest

Csuggest

Dsuggest_field

Attempts:

3 left

💡 Hint

Common Mistakes

Using the suggester name instead of the field name.

Using a field that is not mapped as a completion field.

The completion suggester requires the name of the field that holds the completion data. Here, title is the correct field name.

2fill in blank

medium

Complete the code to add a size limit to the number of suggestions returned.

Elasticsearch

{
  "suggest": {
    "song-suggest": {
      "prefix": "nirv",
      "completion": {
        "field": "title",
        "[1]": 5
      }
    }
  }
}

Drag options to blanks, or click blank then click option'

Asize

Bmax_suggestions

Climit

Dmax_results

Attempts:

3 left

💡 Hint

Common Mistakes

Using limit or max_results which are not valid parameters here.

Using max_suggestions which does not exist.

The size parameter controls how many suggestions are returned by the completion suggester.

3fill in blank

hard

Fix the error in the completion suggester query by completing the missing parameter.

Elasticsearch

{
  "suggest": {
    "song-suggest": {
      "prefix": "nirv",
      "completion": {
        "field": "title",
        "skip_duplicates": [1]
      }
    }
  }
}

Drag options to blanks, or click blank then click option'

A"true"

B"false"

Ctrue

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Putting boolean values in quotes, making them strings.

Using capitalized True which is Python style, not JSON.

The skip_duplicates parameter expects a boolean value without quotes. So true is correct.

4fill in blank

hard

Fill both blanks to create a completion suggester with fuzzy matching enabled and a fuzziness level of 2.

Elasticsearch

{
  "suggest": {
    "song-suggest": {
      "prefix": "nirv",
      "completion": {
        "field": "title",
        "[1]": {
          "fuzziness": [2]
        }
      }
    }
  }
}

Drag options to blanks, or click blank then click option'

Afuzzy

Bfuzziness

C2

D"2"

Attempts:

3 left

💡 Hint

Common Mistakes

Using fuzziness as the first blank instead of fuzzy.

Putting fuzziness level in quotes.

To enable fuzzy matching, set the fuzzy parameter to an object containing fuzziness set to the integer 2.

5fill in blank

hard

Fill all three blanks to create a completion suggester that uses the prefix "nirv", returns 3 suggestions, and skips duplicates.

Elasticsearch

{
  "suggest": {
    "song-suggest": {
      "prefix": "[1]",
      "completion": {
        "field": "title",
        "size": [2],
        "skip_duplicates": [3]
      }
    }
  }
}

Drag options to blanks, or click blank then click option'

Anirv

B3

Ctrue

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using skip_duplicates as a string instead of boolean.

Setting size to a string instead of a number.

The prefix is "nirv", size is 3 to limit suggestions, and skip_duplicates is true to avoid repeated suggestions.

Practice

1. What is the main purpose of the completion suggester in Elasticsearch?

easy

A. To update documents in bulk

B. To perform full-text search on documents

C. To aggregate data based on terms

D. To provide fast autocomplete suggestions as users type

Solution

1. Step 1: Understand the role of completion suggester

   The completion suggester is designed to quickly suggest words or phrases as a user types input.

2. Step 2: Differentiate from other Elasticsearch features

   Full-text search, aggregation, and bulk updates serve different purposes unrelated to autocomplete suggestions.

3. Final Answer:

   To provide fast autocomplete suggestions as users type -> Option D

4. Quick Check:

   Completion suggester = autocomplete suggestions [OK]

Hint: Completion suggester = fast autocomplete feature [OK]

Common Mistakes:

• Confusing completion suggester with full-text search
• Thinking it aggregates data
• Assuming it updates documents

2. Which of the following is the correct way to define a completion field in an Elasticsearch mapping?

easy

A. {
"properties": {
"suggest": { "type": "completion" }
}
}

B. {
"properties": {
"suggest": { "type": "text" }
}
}

C. {
"mappings": {
"suggest": { "type": "completion" }
}
}

D. {
"fields": {
"suggest": { "type": "keyword" }
}
}

Solution

1. Step 1: Identify correct mapping structure

   The completion field must be defined inside properties with type set to completion.

2. Step 2: Compare options

   { "properties": { "suggest": { "type": "completion" } } } correctly uses properties and type: completion. { "properties": { "suggest": { "type": "text" } } } uses text type, which is incorrect. { "mappings": { "suggest": { "type": "completion" } } } wrongly places suggest directly under mappings. { "fields": { "suggest": { "type": "keyword" } } } uses fields and keyword type, which is incorrect.

3. Final Answer:

   { "properties": { "suggest": { "type": "completion" } } } -> Option A

4. Quick Check:

   Completion field in properties with type completion = { "properties": { "suggest": { "type": "completion" } } } [OK]

Hint: Completion field must be under properties with type 'completion' [OK]

Common Mistakes:

• Placing completion field outside properties
• Using text or keyword type instead of completion
• Misnaming mapping keys

3. Given the following suggest query, what will be the expected output if the index contains documents with suggest fields 'apple', 'applet', and 'application'?

{
  "suggest": {
    "fruit-suggest": {
      "prefix": "app",
      "completion": {
        "field": "suggest"
      }
    }
  }
}

medium

A. ["apple", "applet", "application"]

B. ["app", "apple", "applet"]

C. ["application"]

D. []

Solution

1. Step 1: Understand the prefix and completion suggester

   The prefix 'app' matches all suggest entries starting with 'app', which includes 'apple', 'applet', and 'application'.

2. Step 2: Predict the output list

   The completion suggester returns all matching suggestions starting with the prefix, so all three words will be suggested.

3. Final Answer:

   ["apple", "applet", "application"] -> Option A

4. Quick Check:

   Prefix 'app' matches all three suggestions [OK]

Hint: Prefix matches all suggestions starting with it [OK]

Common Mistakes:

• Expecting partial matches inside words
• Thinking prefix must be exact full word
• Assuming empty or partial results

4. Identify the error in this suggest query:

{
  "suggest": {
    "my-suggest": {
      "prefix": "ban",
      "completion": {
        "field": "suggestion"
      }
    }
  }
}

Assuming the mapping defines the completion field as suggest (not suggestion).

medium

A. The prefix value 'ban' is invalid

B. The suggest name 'my-suggest' is not allowed

C. The field name in completion should be 'suggest', not 'suggestion'

D. The suggest query must be inside 'query' key

Solution

1. Step 1: Check field name in completion suggester

   The completion suggester must reference the correct field name defined in the mapping. Here, the mapping uses 'suggest', but the query uses 'suggestion'.

2. Step 2: Validate other parts of the query

   The prefix 'ban' is valid, suggest name 'my-suggest' is allowed, and suggest queries do not require a 'query' key.

3. Final Answer:

   The field name in completion should be 'suggest', not 'suggestion' -> Option C

4. Quick Check:

   Field name mismatch causes error [OK]

Hint: Field name in query must match mapping exactly [OK]

Common Mistakes:

• Using wrong field name in completion query
• Thinking prefix value is invalid
• Expecting suggest query inside 'query' key

5. You want to implement a completion suggester that suggests city names but excludes any suggestions that start with the letter 'x'. Which approach correctly applies this filter in the suggest query?

hard

A. {
"suggest": {
"city-suggest": {
"prefix": "",
"completion": {
"field": "city_suggest",
"skip_duplicates": true
}
}
}
}

B. {
"suggest": {
"city-suggest": {
"prefix": "",
"completion": {
"field": "city_suggest",
"contexts": {
"first_letter": ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "y", "z"]
}
}
}
}
}

C. {
"suggest": {
"city-suggest": {
"prefix": "",
"completion": {
"field": "city_suggest",
"contexts": {
"first_letter": ["!x"]
}
}
}
}
}

D. {
"suggest": {
"city-suggest": {
"prefix": "",
"completion": {
"field": "city_suggest",
"filter": {
"term": { "first_letter": "x" }
}
}
}
}
}

Solution

1. Step 1: Understand filtering with contexts in completion suggester

   Completion suggester supports filtering using contexts. To exclude suggestions starting with 'x', you include all allowed first letters except 'x' in the context filter.

2. Step 2: Analyze each option

   { "suggest": { "city-suggest": { "prefix": "", "completion": { "field": "city_suggest", "skip_duplicates": true } } } } has no filtering. { "suggest": { "city-suggest": { "prefix": "", "completion": { "field": "city_suggest", "contexts": { "first_letter": ["!x"] } } } } } tries to exclude 'x' with '!x' which is invalid syntax. { "suggest": { "city-suggest": { "prefix": "", "completion": { "field": "city_suggest", "contexts": { "first_letter": ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "y", "z"] } } } } } explicitly lists all letters except 'x' in contexts, correctly filtering out 'x'. { "suggest": { "city-suggest": { "prefix": "", "completion": { "field": "city_suggest", "filter": { "term": { "first_letter": "x" } } } } } } uses a 'filter' key which is not supported in completion suggester.

3. Final Answer:

   { "suggest": { "city-suggest": { "prefix": "", "completion": { "field": "city_suggest", "contexts": { "first_letter": ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "y", "z"] } } } } } -> Option B

4. Quick Check:

   Use contexts with allowed letters excluding 'x' [OK]

Hint: Use contexts with allowed letters, exclude 'x' by omission [OK]

Common Mistakes:

• Using invalid '!x' syntax in contexts
• Trying to use 'filter' inside completion suggester
• Not applying context filtering at all