Constant score query in Elasticsearch - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a constant score query with a filter.

Elasticsearch

{
  "constant_score": {
    "filter": [1]
  }
}

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

A{"match": {"status": "active"}}

B{"range": {"age": {"gte": 30}}}

C{"exists": {"field": "user"}}

D{"term": {"status": "active"}}

Attempts:

3 left

💡 Hint

Common Mistakes

Using a match query instead of a filter inside constant_score.

Forgetting to wrap the filter inside the constant_score object.

The constant score query requires a filter clause. Using a term filter like {"term": {"status": "active"}} is correct.

2fill in blank

medium

Complete the code to set the constant score value to 5.

Elasticsearch

{
  "constant_score": {
    "filter": {"term": {"status": "active"}},
    "[1]": 5
  }
}

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

Ascore

Bvalue

Cboost

Dweight

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'score' or 'value' instead of 'boost'.

Placing the boost parameter outside the constant_score object.

The boost parameter sets the constant score value in a constant_score query.

3fill in blank

hard

Fix the error in the constant score query by completing the missing key.

Elasticsearch

{
  "constant_score": {
    [1]: {"term": {"status": "active"}},
    "boost": 3
  }
}

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

A"filter"

B"query"

C"match"

D"term"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'query' instead of 'filter' inside constant_score.

Omitting the quotes around the key.

The constant_score query requires a 'filter' key to wrap the filter query.

4fill in blank

hard

Fill both blanks to create a constant score query filtering by age greater than 25 and setting boost to 2.

Elasticsearch

{
  "constant_score": {
    [1]: {"range": {"age": {"gt": 25}}},
    [2]: 2
  }
}

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

A"filter"

B"boost"

C"query"

D"score"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'query' instead of 'filter'.

Using 'score' instead of 'boost'.

The filter key holds the range filter, and boost sets the constant score value.

5fill in blank

hard

Fill all three blanks to create a constant score query with a term filter on "category" equal to "books", boost 4, and wrap it correctly.

Elasticsearch

{
  [1]: {
    [2]: {"term": {"category": "books"}},
    [3]: 4
  }
}

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

A"constant_score"

B"filter"

C"boost"

D"query"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'query' instead of 'constant_score' or 'filter'.

Misplacing the boost parameter.

The outer key is 'constant_score', inside it 'filter' holds the term filter, and 'boost' sets the score.

Practice

1. What is the main purpose of a constant_score query in Elasticsearch?

easy

A. To filter documents and assign the same score to all matched documents

B. To sort documents by their relevance score

C. To perform a full-text search with varying scores

D. To aggregate documents by a field value

Solution

1. Step 1: Understand the role of constant_score query

   The constant_score query filters documents and assigns the same score to all matches, ignoring relevance scoring.

2. Step 2: Compare with other query types

   Unlike full-text queries that score by relevance, constant_score keeps scores equal for filtered documents.

3. Final Answer:

   To filter documents and assign the same score to all matched documents -> Option A

4. Quick Check:

   constant_score = equal scoring for filtered docs [OK]

Hint: Constant score means all matched docs get the same score [OK]

Common Mistakes:

• Thinking it sorts by relevance
• Confusing with full-text scoring
• Assuming it aggregates data

2. Which of the following is the correct syntax to create a constant score query with a filter on field status equal to active?

easy

A. {"constant_score": {"filter": {"match": {"status": "active"}}}}

B. {"constant_score": {"query": {"term": {"status": "active"}}}}

C. {"constant_score": {"term": {"status": "active"}}}

D. {"constant_score": {"filter": {"term": {"status": "active"}}}}

Solution

1. Step 1: Identify correct key for filtering

   The constant_score query uses the key "filter" to specify the filter clause, not "query" or direct term.

2. Step 2: Check filter syntax

   The filter should be a term query inside the filter object, correctly written as {"term": {"status": "active"}}.

3. Final Answer:

   {"constant_score": {"filter": {"term": {"status": "active"}}}} -> Option D

4. Quick Check:

   Use "filter" with term inside constant_score [OK]

Hint: Use "filter" key with term query inside constant_score [OK]

Common Mistakes:

• Using "query" instead of "filter"
• Placing term query directly under constant_score
• Using match instead of term for exact filter

3. Given this Elasticsearch query snippet, what will be the score of each matched document?

{
  "constant_score": {
    "filter": { "term": { "category": "books" } },
    "boost": 3
  }
}

medium

A. The score will vary based on relevance

B. The score will be 3 for all matched documents

C. The score will be 1 for all matched documents

D. The score will be 0 because boost is ignored

Solution

1. Step 1: Understand constant_score with boost

   The constant_score query assigns the same score to all matched documents, and the boost multiplies that score.

2. Step 2: Calculate the score

   By default, constant_score gives score 1, multiplied by boost 3, resulting in score 3 for all matches.

3. Final Answer:

   The score will be 3 for all matched documents -> Option B

4. Quick Check:

   constant_score x boost = 3 [OK]

Hint: Boost multiplies constant score, so score = boost value [OK]

Common Mistakes:

• Assuming scores vary by relevance
• Ignoring the boost value
• Thinking boost is ignored in constant_score

4. Identify the error in this constant score query:

{
  "constant_score": {
    "filter": {
      "terms": {
        "tags": ["tech", "science"]
      }
    },
    "boost": "2"
  }
}

medium

A. The boost value should be a number, not a string

B. The filter key should be replaced with query

C. The terms query cannot be used inside constant_score

D. The tags field should be inside a match query

Solution

1. Step 1: Check boost data type

   The boost parameter must be a numeric value, not a string. Here, "2" is a string, which is invalid.

2. Step 2: Validate filter and terms usage

   Using "filter" with a "terms" query is valid syntax, so no error there.

3. Final Answer:

   The boost value should be a number, not a string -> Option A

4. Quick Check:

   boost must be numeric, not string [OK]

Hint: Boost must be a number, not quoted string [OK]

Common Mistakes:

• Using string for boost instead of number
• Replacing filter with query incorrectly
• Misunderstanding terms query usage

5. You want to find all documents where status is published and boost their score by 5, but keep all matched documents scored equally. Which query correctly achieves this?

hard

A. { "match": { "status": "published", "boost": 5 } }

B. { "bool": { "must": { "term": { "status": "published" } }, "boost": 5 } }

C. { "constant_score": { "filter": { "term": { "status": "published" } }, "boost": 5 } }

D. { "constant_score": { "query": { "term": { "status": "published" } }, "boost": 5 } }

Solution

1. Step 1: Use constant_score with filter and boost

   To keep scores equal and apply a boost, use constant_score with a filter clause and boost parameter.

2. Step 2: Validate correct syntax

   { "constant_score": { "filter": { "term": { "status": "published" } }, "boost": 5 } } uses "filter" with a term query and numeric boost, which is the correct syntax.

3. Step 3: Check other options

   { "bool": { "must": { "term": { "status": "published" } }, "boost": 5 } } uses bool query which scores by relevance, not constant. { "match": { "status": "published", "boost": 5 } } is a match query with boost but scores vary. { "constant_score": { "query": { "term": { "status": "published" } }, "boost": 5 } } incorrectly uses "query" instead of "filter" inside constant_score.

4. Final Answer:

   { "constant_score": { "filter": { "term": { "status": "published" } }, "boost": 5 } } -> Option C

5. Quick Check:

   constant_score + filter + boost = equal boosted scores [OK]

Hint: Use constant_score with filter and numeric boost for equal boosted scores [OK]

Common Mistakes:

• Using query instead of filter inside constant_score
• Using bool or match queries that score variably
• Setting boost as string instead of number