Completion suggester in Elasticsearch - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this completion suggester query?

Given the following Elasticsearch completion suggester query, what will be the returned suggestion text?

Elasticsearch

{
  "suggest": {
    "song-suggest": {
      "prefix": "lov",
      "completion": {
        "field": "suggest",
        "size": 1
      }
    }
  }
}

A ["love story"]

B ["lovely day"]

C []

D ["lover boy"]

💡 Hint

Check the indexed suggestions that start with the prefix "lov".

The completion suggester returns suggestions starting with the prefix "lov". Assuming the indexed data contains "love story" as a suggestion, it will be returned as the top suggestion.

🧠 Conceptual

intermediate

Which field type is required for using completion suggester?

To use the completion suggester in Elasticsearch, which field mapping type must be used?

A "keyword"

B "text"

C "completion"

D "nested"

💡 Hint

Look for the specialized field type designed for fast prefix suggestions.

The completion suggester requires the field to be mapped as type "completion" to enable fast prefix-based suggestions.

🔧 Debug

advanced

Why does this completion suggester query return no suggestions?

Consider this query that returns no suggestions despite data being indexed:

{
  "suggest": {
    "user-suggest": {
      "prefix": "jo",
      "completion": {
        "field": "user_suggest",
        "skip_duplicates": true
      }
    }
  }
}

What is the most likely cause?

A The prefix "jo" is too short for suggestions.

B The "skip_duplicates" parameter disables all suggestions.

C The query syntax is invalid and causes an error.

D The field "user_suggest" is not mapped as "completion" type.

💡 Hint

Check the field mapping type for "user_suggest".

If the field is not mapped as "completion" type, the completion suggester will not work and return no suggestions.

📝 Syntax

advanced

Which option correctly uses the completion suggester with contexts?

Which of the following JSON queries correctly uses a context filter in a completion suggester?

A

{
  "suggest": {
    "product-suggest": {
      "prefix": "iph",
      "completion": {
        "field": "product_suggest",
        "contexts": {
          "category": "smartphones"
        }
      }
    }
  }
}

B

{
  "suggest": {
    "product-suggest": {
      "prefix": "iph",
      "completion": {
        "field": "product_suggest",
        "contexts": {
          "category": ["smartphones"]
        }
      }
    }
  }
}

C

{
  "suggest": {
    "product-suggest": {
      "prefix": "iph",
      "completion": {
        "field": "product_suggest",
        "contexts": [
          {"category": "smartphones"}
        ]
      }
    }
  }
}

D

{
  "suggest": {
    "product-suggest": {
      "prefix": "iph",
      "completion": {
        "field": "product_suggest",
        "context": {
          "category": ["smartphones"]
        }
      }
    }
  }
}

💡 Hint

Check the correct key name and value type for contexts in completion suggester.

The "contexts" key expects an object where each context name maps to an array of context values.

🚀 Application

expert

How many suggestions will this completion suggester return?

Given this query:

{
  "suggest": {
    "city-suggest": {
      "prefix": "new",
      "completion": {
        "field": "city_suggest",
        "size": 3
      }
    }
  }
}

And the indexed suggestions are: "new york", "newark", "new orleans", "newcastle", "newport". How many suggestions will be returned?

A 3

B 5

C 1

D 0

💡 Hint

Look at the "size" parameter in the query.

The "size" parameter limits the number of suggestions returned to 3, even if more matches exist.