ElasticSearch Interview questions and Answers
Q1. What is an index in ElasticSearch ?
Ans: An index is much like a desk in relational databases. The distinction is that relational databases could save actual values, that is elective in ElasticSearch. An index can store actual and/or analyzed values in an index.
Q2. What is a record in ElasticSearch ?
Ans: A record is just like a row in relational databases. The distinction is that each document in an index can have a exclusive shape (fields), but have to have equal information type for not unusual fields.
Each subject can occur multiple times in a document with unique records kinds. Fields can include different documents too.
Q3. Does ElasticSearch have a schema ?
Ans: Yes, ElasticSeach will have mappings which can be used to implement schema on files.
Q4. What is a file kind in ElasticSearch ?
Ans: A document type may be visible because the document schema / mapping definition, which has the mapping of all of the fields in the document along side its records sorts.
Q5.What is indexing in ElasticSearch ?
Ans: The system of storing data in an index is referred to as indexing in ElasticSearch. Data in ElasticSearch may be dividend into write-as soon as and study-many segments. Whenever an replace is tried, a new edition of the record is written to the index.
Q6. What is a node in ElasticSearch ?
Ans: Each instance of ElasticSearch is known as a node. Multiple nodes can paintings in concord to shape an ElasticSearch Cluster.
Q7.What is a shard in ElasticSearch ?
Ans: Due to resource boundaries like RAM, vCPU etc, for scale-out, applications need to appoint more than one times of ElasticSearch on separate machines. Data in an index may be divided into a couple of partitions, every handled by using a separate node (instance) of ElasticSearch. Each such partition is called a shard. By default an ElasticSearch index has five shards.
Q8. What is a replica in ElasticSearch ?
Ans: Each shard in ElasticSearch has 2 copy of the shard. These copies are referred to as replicas. They serve the reason of high-availability and fault-tolerance.
Q9. What is an Analyzer in ElasticSearch ?
Ans: While indexing records in ElasticSearch, records is transformed internally with the aid of the Analyzer defined for the index, and then listed. An analyzer is built of tokenizer and filters. Following varieties of Analyzers are available in ElasticSearch 1.10.
Q10. What is a Tokenizer in ElasticSearch ?
Ans: A Tokenizer breakdown fields values of a document into a circulation, and inverted indexes are created and updates the usage of these values, and those flow of values are saved within the file.
Q11. What is a Filter in ElasticSearch ?
Ans: After information is processed with the aid of Tokenizer, the equal is processed by way of Filter, before indexing. Following styles of Filters are to be had in ElasticSearch 1.10.
GEO BOUNDING BOX FILTER
GEO DISTANCE FILTER
GEO DISTANCE RANGE FILTER
GEO POLYGON FILTER
GEOHASH CELL FILTER
HAS CHILD FILTER
HAS PARENT FILTER
MATCH ALL FILTER
Q12. What is the question language of ElasticSearch ?
Ans: ElasticSearch uses the Apache Lucene question language, that's called Query DSL.
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