Elasticsearch Interview Questions and Answers

Ques 1. Describe the 'Scripting' feature in Elasticsearch.

Scripting allows users to write custom scripts for advanced calculations, filtering, and scoring in Elasticsearch queries.

Ques 2. How does the 'Fuzzy' query work in Elasticsearch?

The 'Fuzzy' query in Elasticsearch is used to find approximate matches for a given query term. It is useful for handling typos or variations in spelling.

Example:

GET /my_index/_search
{
  "query": {
    "fuzzy": {
      "field": "value",
      "fuzziness": 2
    }
  }
}

Ques 3. How does Elasticsearch handle conflicts during index updates?

Elasticsearch uses a versioning mechanism to handle conflicts during index updates and ensure consistency.

Ques 4. Explain the purpose of the 'Reindex' API in Elasticsearch.

The 'Reindex' API is used to copy documents from one index to another. It is useful for reorganizing data, changing mappings, or upgrading Elasticsearch versions.

Example:

POST _reindex
{
  "source": {
    "index": "old_index"
  },
  "dest": {
    "index": "new_index"
  }
}

Ques 5. What is the 'Wildcards' query in Elasticsearch used for?

The 'Wildcards' query allows you to perform wildcard-based searches on string fields. It supports '*' for any number of characters and '?' for a single character.

Example:

GET /my_index/_search
{
  "query": {
    "wildcard": {
      "field": "va*lue"
    }
  }
}