Creating an index in Elasticsearch - Practice Exercises

Challenge - 5 Problems

❓ query_result

intermediate

What is the output of this index creation request?

Given the following Elasticsearch request to create an index named library with a simple mapping, what will be the response status?

Elasticsearch

{
  "mappings": {
    "properties": {
      "title": { "type": "text" },
      "author": { "type": "keyword" },
      "year": { "type": "integer" }
    }
  }
}

A {"acknowledged":true,"shards_acknowledged":true,"index":"library"}

B {"error":"index_already_exists_exception","status":400}

C {"acknowledged":false,"shards_acknowledged":false,"index":"library"}

D {"error":"illegal_argument_exception","status":400}

💡 Hint

Successful index creation returns acknowledged: true.

When an index is created successfully, Elasticsearch returns a JSON with acknowledged and shards_acknowledged set to true, and the index name.

🧠 Conceptual

intermediate

Which setting controls the number of primary shards when creating an index?

When creating an Elasticsearch index, which setting defines how many primary shards the index will have?

A "number_of_replicas"

B "refresh_interval"

C "index_buffer_size"

D "number_of_shards"

💡 Hint

Think about how data is split across the cluster.

The number_of_shards setting controls how many primary shards an index has. This determines how the data is divided.

📝 Syntax

advanced

Which JSON snippet correctly creates an index with 3 replicas?

Select the correct JSON body to create an Elasticsearch index named products with 1 primary shard and 3 replicas.

A

{
  "settings": {
    "number_of_shards": 1,
    "number_of_replicas": 3
  }
}

B

{
  "settings": {
    "shards": 1,
    "replicas": 3
  }
}

C

{
  "settings": {
    "number_of_shards": "1",
    "number_of_replicas": "3"
  }
}

D

{
  "settings": {
    "number_of_shards": 3,
    "number_of_replicas": 1
  }
}

💡 Hint

Settings keys must be exact and values numeric, not strings.

The correct keys are number_of_shards and number_of_replicas. Values should be numbers, not strings. Option A matches this exactly.

🔧 Debug

advanced

Why does this index creation fail?

Consider this request to create an index named users with a mapping:

{
  "mappings": {
    "properties": {
      "name": { "type": "text" },
      "age": { "type": "integer" },
      "email": { "type": "keyword" }
    }
  },
  "settings": {
    "number_of_shards": 0
  }
}

Why will this request fail?

A Because <code>mappings</code> must be inside <code>settings</code>

B Because <code>integer</code> type is not allowed in mappings

C Because <code>number_of_shards</code> cannot be zero; it must be at least 1

D Because <code>keyword</code> type is invalid for <code>email</code>

💡 Hint

Think about shard count limits.

Elasticsearch requires at least one primary shard. Setting number_of_shards to zero is invalid and causes the request to fail.

❓ optimization

expert

Which index setting improves search speed by disabling _source storage?

You want to optimize an Elasticsearch index for search speed and reduce storage size. Which setting disables storing the original JSON document and can improve performance?

A "store": { "enabled": false }

B "_source": { "enabled": false }

C "index.store.type": "none"

D "refresh_interval": "-1"

💡 Hint

The original JSON document is stored in a special field called _source.

Disabling _source storage with "_source": { "enabled": false } stops Elasticsearch from storing the original JSON, reducing storage and improving search speed, but you lose the ability to retrieve the original document.