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Elasticsearch Objective Questions and Answers
This Elasticsearch quiz contains carefully curated objective questions with correct answers and clear explanations. It is designed for developers, backend engineers, and interview preparation, covering indexing, querying, aggregation, scaling, and performance optimization techniques.
Practice Elasticsearch MCQs with Detailed Explanations
Answer at least 12 questions to submit and verify answers.
1 What is Elasticsearch primarily used for? Easy
Correct answer:
Full-text search and analytics
Elasticsearch is a distributed search and analytics engine optimized for full-text search and real-time data analysis.
2 Which data structure is used internally by Elasticsearch for efficient search? Medium
Correct answer:
Inverted Index
Elasticsearch uses an inverted index to map terms to documents, enabling fast full-text search queries.
3 What is a shard in Elasticsearch? Medium
Correct answer:
A partition of an index
A shard is a subset of an index, allowing Elasticsearch to distribute and scale data across nodes.
4 What is the default number of primary shards in Elasticsearch 7.x+? Medium
Correct answer:
1
Elasticsearch 7.x sets the default number of primary shards to 1 for better resource utilization.
5 Which API is used to insert a document into Elasticsearch? Medium
Correct answer:
PUT /index/_doc/id
The PUT API is used to index (insert/update) a document with a specific ID.
6 What is a replica shard? Medium
Correct answer:
A duplicate of a primary shard
Replica shards provide redundancy and improve search performance by duplicating primary shards.
7 Which query is used for exact matches? Medium
Correct answer:
term query
Term query does not analyze input and is used for exact matches, typically on keyword fields.
8 What does the match query do? Medium
Correct answer:
Full-text search
Match query analyzes input text and performs full-text search.
9 Which field type is best for sorting and aggregations? Medium
Correct answer:
keyword
Keyword fields are not analyzed and are optimized for sorting and aggregations.
10 What is the purpose of analyzers in Elasticsearch? Medium
Correct answer:
Transform text during indexing/search
Analyzers process text into tokens for indexing and searching.
11 Which aggregation is used to group data? Medium
Correct answer:
terms aggregation
Terms aggregation groups documents based on field values.
12 What does the bool query 'must' clause represent? Medium
Correct answer:
Mandatory condition
The must clause defines conditions that documents must satisfy.
13 Which clause excludes documents? Medium
Correct answer:
must_not
must_not excludes documents matching the condition.
14 What is the purpose of the filter clause? Medium
Correct answer:
Caching and filtering without scoring
Filter clause is used for fast filtering without affecting score and is cacheable.
15 Which API is used for bulk operations? Medium
Correct answer:
/_bulk
Bulk API allows multiple indexing or delete operations in a single request.