面试题与答案

Elasticsearch is a distributed search and analytics engine built on top of Apache Lucene.

An index in Elasticsearch is a collection of documents that share a similar structure and are stored together for efficient searching.

A document is the basic unit of information in Elasticsearch, represented in JSON format.

A cluster is a collection of nodes that work together and share the same cluster name, forming a single logical unit.

A node is a single instance of Elasticsearch running within a cluster, storing data and participating in cluster operations.

Tokenization is the process of breaking a text into individual terms or tokens, which become searchable in Elasticsearch.

Refresh makes changes to the index immediately visible for search, but it comes with a performance cost.

Filters are used to narrow down the search results based on specific criteria without affecting scoring.

The Bulk API allows for the efficient indexing and deletion of multiple documents in a single request.

The CAT API provides concise information about the cluster, indices, and nodes in a human-readable format.

Elasticsearch is a distributed search and analytics engine built on top of Apache Lucene. It provides a scalable and real-time search solution.

Example:

GET /index/_search?q=query

A node is a single instance of Elasticsearch running on a machine. It is part of a cluster and stores data and participates in the indexing and search capabilities of Elasticsearch.

Example:

GET /_cat/nodes?v

The 'Cat' API in Elasticsearch provides concise and human-readable information about the cluster, nodes, indices, and other components. It is useful for monitoring and debugging.

Example:

GET /_cat/indices?v

The 'Cluster Health' API provides information about the overall health of the Elasticsearch cluster, including the status of nodes, indices, and other vital statistics.

Example:

GET /_cluster/health

You can use the 'size' parameter in your query to limit the number of results returned. For example, 'size': 10 will return only 10 documents.

Example:

GET /my_index/_search
{
  "query": {
    "match_all": {}
  },
  "size": 10
}