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Elasticsearch Objective Questions and Answers - Set 3
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. This is part 3 of the series.
Practice Elasticsearch MCQs with Detailed Explanations
Answer at least 12 questions to submit and verify answers.
31 Which query allows optional clauses? Medium
Correct answer:
should
Should clauses are optional but improve scoring if matched.
32 What is the default scoring algorithm? High
Correct answer:
BM25
Elasticsearch uses BM25 as the default similarity algorithm.
33 What is snapshot used for? Medium
Correct answer:
Backup and restore
Snapshots are used for backups and restoring indices.
34 Which API checks cluster health? Medium
Correct answer:
/_cluster/health
Cluster health API provides cluster status information.
35 What does 'green' cluster status mean? Medium
Correct answer:
All shards allocated
Green status means all primary and replica shards are allocated.
36 Which query supports fuzziness? Medium
Correct answer:
match
Match query supports fuzziness for approximate matches.
37 What is the purpose of index templates? High
Correct answer:
Define default mappings/settings
Index templates apply predefined settings and mappings to new indices.
38 Which API deletes an index? Easy
Correct answer:
DELETE /index
DELETE API removes an index and its data.
39 What is fielddata used for? High
Correct answer:
Sorting on text fields
Fielddata enables sorting/aggregation on text fields but is memory intensive.
40 What is a nested field? High
Correct answer:
Array of objects with independent indexing
Nested fields allow querying objects independently within arrays.
41 Which API updates a document partially? Medium
Correct answer:
POST _update
Update API modifies part of a document.
42 What is scroll API used for? High
Correct answer:
Deep pagination
Scroll API is used to retrieve large datasets efficiently.
43 What is the purpose of routing? High
Correct answer:
Control shard placement
Routing determines which shard a document is stored in.
44 Which feature improves indexing performance? Medium
Correct answer:
Bulk API
Bulk API reduces overhead and improves indexing performance.
45 What happens when a node fails? Medium
Correct answer:
Replica shards are promoted
Replica shards are promoted to primary to maintain availability.