ElasticSearch ElasticSearch 3

Question 1

Which Elasticsearch component is responsible for routing documents to the correct primary shard?

Accepted Answer

The coordinating node using a hash of the document ID

Answer

By default, Elasticsearch routes documents to shards using a hash of the document ID modulo the number of primary shards.

Question 2

What is a 'near real-time' (NRT) search in Elasticsearch?

Accepted Answer

Search that becomes available within ~1 second after indexing due to refresh intervals

Answer

Elasticsearch is near real-time because indexed documents become searchable only after a refresh (default every 1 second), not immediately.

Question 3

In Elasticsearch, what does the `must_not` clause in a bool query do?

Accepted Answer

Excludes documents that match any of the listed queries

Answer

The must_not clause excludes documents that match any of its queries, and matching documents contribute a score of 0.

Question 4

What is the role of a 'master-eligible' node in an Elasticsearch cluster?

Accepted Answer

To participate in master election and manage cluster state

Answer

Master-eligible nodes can be elected as the cluster master, which manages cluster-wide settings, shard allocation, and node membership.

Question 5

Which Elasticsearch API is used to retrieve the mapping of an index?

Accepted Answer

GET /<index>/_mapping

Answer

The GET `/<index>/_mapping` API returns the field mappings defined for the specified index.

ElasticSearch Practice Test