This Elasticsearch Interview Questions blog can assist in getting you prepared. Here we have provided you with a selection of frequently askedElastic Search Interview Questions, an open source analytics and search engine platform built upon Apache Lucene.

Elasticsearch is often employed for log analytics, application monitoring and real-time search purposes. Due to its scalability and robust feature set, Elasticsearch is highly esteemed in the tech sector.

These questions aim to assess your knowledge of Elasticsearch’s architecture, data modeling capabilities, indexing features and search capabilities, no matter your level of experience with its platform.

So let’s get cracking and find out more about its applications!

1. What is Elasticsearch?

Elasticsearch is based on Apache Lucene, which allows for various types of searching. It supports full-text search and different search mechanisms.

2. What are the benefits of using Elasticsearch?

Elasticsearch offers benefits such as query capabilities, which combine structured and unstructured searches, working on data based on geography and metrics.

It also supports significant volumes of data and provides aggregation, allowing users to zoom out and explore trends and patterns in their data.

3. Is Elasticsearch scalable?

Yes, Elasticsearch is scalable and allows for scaling across multiple nodes.

4. What is the role of Apache Lucene in Elasticsearch?

Elasticsearch is based on Apache Lucene, which underpins its search and indexing capabilities.

5. What does Elasticsearch use the document-oriented approach?

Elasticsearch follows a document-oriented approach, storing data in documents rather than schemas and tables.

6. How is Elasticsearch installed on a Windows platform?

Java must be installed to install Elasticsearch on a Windows platform, and environment variables must be set appropriately. The Elasticsearch zip file should be downloaded from the website and unzipped.

7. How is Elasticsearch accessed?

Elasticsearch can be accessed using JSON over HTTP, a RESTful API.

8. What is the difference between bulk operations and re-indexing in database management?

Bulk operations allow for multiple operations simultaneously, while re-indexing involves creating a test index to perform operations on a specific part of an index.

Re-indexing is particularly useful when there are numerous records in an index, and adding new fields may impact the deletion of all documents.

9. In which programming language is Elasticsearch developed?

Elasticsearch is developed in Java.

10. What is a cluster in Elasticsearch?

A cluster is a collection of one or more nodes holding all the data and providing federated indexing and search capabilities.

11. What is an index in Elasticsearch?

An index is a collection of documents with similar characteristics and is identified by a name.

12. What are the APIs used in Elasticsearch?

Elasticsearch uses variousAPIs to perform multiple operations, including indexing, searching, updating, and deleting.

13. What is a document in Elasticsearch?

Documents are basic units of information expressed in JSON format, which is an internet-friendly format.

14. What is URL-based access control in Elasticsearch?

URL-based access control allows users to secure the access of Elasticsearch indexes by using proxies.

15. How is a single record deleted in Elasticsearch?

To delete a single record in Elasticsearch, you can update the database by query and then delete the index name, document, and ID where the data will be read.

16. What is the difference between an update operation with a query and scripting languages?

The update operation with a query is used to update a document based on the query provided. Scripting languages, however, are used to write custom scripts for editing and deleting documents.

17. What are the different types of APIs in Elasticsearch?

Elasticsearch offers several APIs, including document, search, aggregation, cluster, and index APIs.

18. What is the difference between multi-get API, bulk API, and Elasticsearch?

Multi-get API is a multi-document search and operation that allows for multiple search conditions and documents from which results can be obtained.

Bulk API is a batch update operation that allows various updates to be performed simultaneously.

19. What are the two types of document APIs in Elasticsearch?

The two types of document APIs in Elasticsearch are single API documents and multiple API notes.

20. How can you check if Elasticsearch runs on your local machine?

You can check if Elasticsearch is running by opening the browser on the same machine and typing ‘localhost: 9200’ to see if it displays the tagline for the search.

21. What is the difference between a single API document and multiple API recordsin Elasticsearch?

A singleAPI document performs operations at the index level, while multiple document API records, such as multi-gearedAPI and bulk API, perform operations across various documents.

22. How is a document created in Elasticsearch?

To create a document in Elasticsearch, the query involves using the get method to import the document into the index, which contains information like title, artist, and album.

23. How is a document updated in Elasticsearch?

The put method is used to update a document in Elasticsearch, and parameters can be added based on the index name and document ID.

24. How is a document deleted in Elasticsearch?

The delete method is used to delete a document in Elasticsearch, and the successful one means the document has been deleted.

25. What is search API in Elasticsearch?

Search API allows users to extend a search query and retrieve results from a data set.

26. What is aggregation in Elasticsearch?

Aggregation is a framework that collects data from multiple data sets selected by a search query.

27. What are the building blocks of aggregation in Elasticsearch?

The building blocks of aggregation in Elasticsearch are bucket, metric, matrix, and pipeline.

28. Can you explain how to use aggregation on a bank data set?

You can run queries that retrieve documents with specific criteria to use aggregation on a bank data set in Elasticsearch.

29. What are the different types of queries that can be executed using aggregation in Elasticsearch?

Several queries can be executed using Elasticsearch aggregation, including range and filter queries.

30. What are index APIs used for in Elasticsearch?

Index APIs manage all aspects of indexes, including settings, aliases, mapping, and index templates.

31. What is the difference between cluster APIs and index APIs in Elasticsearch?

Cluster APIs are used to get information about the cluster and its nodes and make changes in them.

On the other hand, Index APIs manage all aspects of indexes.

32. What is Query DSL used for in Elasticsearch?

Query DSL defines queries in Elasticsearch, a domain-specific language based on JSON.

33. What is the difference between various scripting languages used in SQL?

Painless, Bandwidth, Expressions, and Groovy are different scripting languages used in SQL.

Painless is a simple scripting language; bandwidth is used for parallel processing, expressions are used for mathematical operations, and Groovy is used for complex scripting operations.

34. What are the two types of clauses in Query DSL?

The two types of clauses in Query DSL are the leaf query clause and the compound query clause.

35. How is Elasticsearch stored?

Elasticsearch stores documents and fields using a combination of leaf and branch structures.

36. What is mapping in Elasticsearch?

Mapping is a process in Elasticsearch that defines how a document and its fields are stored and indexed.

37. What are the different mapping types in Elasticsearch?

There are several mapping types in Elasticsearch, including document, nested, parent-child, and object.

38. What are the different field types in Elasticsearch?

Several field types in Elasticsearch include text, integer, date, double, boolean, keyword, and parent-child.

39. What is analysis in Elasticsearch?

Analysis is a process in Elasticsearch that converts fields into tokens and performs operations.

40. What are the different types of modules in Elasticsearch?

There are two types of modules in Elasticsearch: static and dynamic.

41. What is the difference between static and dynamic modules in Elasticsearch?

Static settings must be configured in the YML file before starting Elasticsearch, while dynamic modules are default.

42. What is Elasticsearch API?

Elasticsearch API is the document API, search API, indices, CAD, and cluster API.

43. What can be done with a single document API in Elasticsearch?

Single document API allows you to add or update a type of JSON document in the specific index and make it searchable.

44. How is data posted in JSON in an index in Elasticsearch?

To post data in JSON in an index, you must write a post command with the index name, such as “insert a row in one table.”

This will insert a record in the specified field, which is nested and can have address numbers, location names, state names, city names, etc.

45. What is the use of the post command in Elasticsearch?

The post command in Elasticsearch is used to insert data into a specified field in an index.

46. Can the nested field be edited in Elasticsearch?

Yes, the nested field can be edited in Elasticsearch.

47. What is the difference between the index API and the search API in Elasticsearch?

The index API adds operations on a table in JSON format, while the search API retrieves data from the index.

48. What is the use of the GET API in Elasticsearch?

The GET API in Elasticsearch fetches all records by specifying the table name and the search query size.

49. What is the use of the count number in mapping in Elasticsearch?

The count number in mapping in Elasticsearch helps determine the total number of records in an index.

50. What is the underscore search dot operator in SQL?

SQL’s underscore search dot operator assigns values to the underscore source, resulting in the record update with the specified value.

51. What is the difference between simple SQL and query updates?

Simple update is used to update a single record, while query update is used to update multiple records based on the query provided.

52. What is the use of script suggestions in SQL?

Script suggestions are provided to help users write scripts with proper syntax.

53. What is the syntax of GUID in SQL?

The syntax of GUID in SQL includes specifying the script, source, and path.

54. How is the updatebyquery operation used for multi-document operations in Elasticsearch?

The update bya query operation in Elasticsearch is used for multi-document operations by performing a match operation on all documents where the specified condition matches.

55. What is the use of multi-get API in Elasticsearch?

Multi-get API is a multi-document search and operation that requires the index name, types, and ID to get search values.

56. What is the use of bulk API in Elasticsearch?

Bulk API allows for bulk operations such as update, delete, and creation while maintaining a fast response rate.

57. What is the use of re-index API in Elasticsearch?

The re-indexAPI updates the index based on the changes made to the data source. It is beneficial when adding fields or changing data formats, as it may impact the deletion of all records.

58. Can you name a tool used with Elasticsearch for making queries through its UI?

The Kibana dashboard makes queries through its user interface with Elasticsearch.

Check out our selected MCQ area for a wide selection of frequent interview questions and ace your interview.

1. What programming language is Elasticsearch developed in?

a) JavaScript

b) C++

c) Python

d) Java

2.Which type of interface does Elasticsearch provide for interaction?

a) SOAP interfaces

b) GraphQL interfaces

c) RPC interfaces

d) RESTful interfaces
3. Does Elasticsearch store data in the form of?

a) nodes

b) Documents

c) Relations

d) Tables

4. What kind of system is Elasticsearch considered?

a) Localised

b) Isolated

c) Centralised

d) Distributed

5. What does Elasticsearch allow users to do with their data?

a) Query and Analyse

b) Model and Simulate

c) Compile and Execute

d) Encrypt and Decrypt

6. To install Elasticsearch on Windows, what prerequisite software must be installed?

a) Java

b) Node.js

c) .NET Framework

d) Python

7. What does the ‘cluster’ in Elasticsearch define?

a) Collection of one or more nodes

b) Type of search operation

c) Aggregation framework

d) Single data record

8. In Elasticsearch, what constitutes a ‘document’?

a) SQL data entry

b) binary log file

c)Basic unit of information expressed in JSON format

d) An XML configuration file

9. Which API provided by Elasticsearch performs operations at the document level?

a) Cluster APIs

b) Document APIs

c) Aggregation APIs

d) Index APIs

10. Where do you go to check if your local Elasticsearch instance is running?

a) localhost:5432

b) localhost:8080

c) localhost:3306

d) localhost:9200

We hope these Interview Questions on Elasticsearch have provided the essential knowledge to ace any forthcoming interviews by providing you with an in-depth knowledge of its advanced features and principles.

Hope all your future efforts go successfully! I hope this blog can assist in your preparations for an Elasticsearch interview – best wishes!