ElasticSearch Interview Questions

ElasticSearch is a Search Engine based on Apache Lucene that supports FullText Search.

ElasticSearch can be used to search different kinds of documents that provide scalable search, multi-tenancy, and real-time search.

ElasticSearch is developed in Java (Developed By - Shay Banon) and is released as open source under the terms of the Apache License.

curl -L -O https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.3.1-linux-x86_64.tar.gz
tar -xzvf elasticsearch-7.3.1-linux-x86_64.tar.gz
cd elasticsearch-7.3.1
./bin/elasticsearch

Steps to Install ElasticSearch on Windows:

1. Download the Elasticsearch 7.3.1 Windows zip file from the ElasticSearch Download page.
2. Extract the contents of the zip file to a directory on your computer.(e.g. - C:\ElasticSearch.)
3. Open Command Prompt as an Administrator and navigate to the directory that contains the extracted files

   cd C:\ElasticSearch\elasticsearch-7.3.1
   

4. Start Elasticsearch:

bin\elasticsearch.bat

For other OS you may follow ElasticSearch Official Guide

To test that the Elasticsearch is up and running, try sending an HTTP GET request on port 9200.

curl http://127.0.0.1:9200

ElasticSearch uses apache lucene query language, which is called Query DSL.

ElasticSearch uses a structure called an inverted index, which is designed to allow very fast full-text searches. An inverted index consists of a list of all the unique words that appear in any document, and for each word, a list of the documents in which it appears.

You may also like - Solr Search Interview Questions

In simple word - Tokenizers break down a string into stream of tokens.

Yes, ElasticSearch can have a schema.

Following are the advantages of ElasticSearch:

1. ElasticSearch is compatible on any platform.
2. ElasticSearch cluster is distributed, scalable and most important easy to integrate.
3. ElasticSearch REST uses JSON objects, works perfectly with different programming languages.

You may also like - Node.js Interview Questions