indices in elasticsearch

Question

What are Elasticsearch indices and how are they structured? How do you create, delete, and optimize indices for specific use cases? How do shards and replicas affect indexing and search performance? Can you provide examples of scenarios where the configuration of indices may need to be modified?

Answer 1

An index in Elasticsearch is a collection of documents that have similar characteristics. Indices are created to store, retrieve, and manage data efficiently. They are structured similarly to a database table and can be created using various mapping options to define the fields and data types of the documents they will store. Indices can be optimized for specific use cases, such as search or indexing, by adjusting their configuration, such as the number of shards or replicas.

Elasticsearch also offers the ability to scale indices by dividing them into shards, which can be distributed across multiple nodes in a cluster and replicated for improved performance and reliability. Understanding and properly managing indices is important for optimizing the performance and functionality of an Elasticsearch cluster.

Answer 2

In Elasticsearch, an index is a collection of documents that have similar characteristics. Indices are used to store, retrieve, and manage data efficiently. To list all the indices in an Elasticsearch cluster, you can use the GET _cat/indices API. This will return a list of all the indices in the cluster along with their metadata, such as the index name, number of shards and replicas, and the status of the index.

You can also use the GET _cat/indices/<index_name> API to get information about a specific index. It's important to properly manage your indices in Elasticsearch, as they play a key role in the performance and functionality of your cluster.