Here are some common elaborate on the meaning of words among ES:
Clusters
Cluster consists of one or more nodes, provide services, indexing and search capabilities. In all nodes in a cluster have a unique name defaults to "ElasticSearch", this name is important because each node can only be part of a cluster, when the node is set to the same cluster name, it will automatically join the cluster. When you need multiple clusters, each cluster to ensure that the name can not be repeated, otherwise, the node may join the wrong cluster.
node
A node is a server in your cluster, as part of a cluster, it stores your data, indexing and search capabilities to participate in the cluster. And similar clustering, a node is identified by the name of
index
An index is a collection has somewhat similar features of the document. For example, you can have an index of customer data, another index catalog, there is an index order data. An index consists of a name is identified (must be all lowercase letters), and when we want to index, search for the index corresponding to this document, update, and delete, to have to use that name. In a cluster, you can define any number of indexes.
Types of
In the index, one or more types may be defined, the type of logical partitioned index, corresponding to the database table.
File
JSON string is a document stored in the ES, corresponding to line tables in the database, ES is an unstructured database, each document can have a different field, and has a unique identifier
Field
Similarly a column of a relational database, which is the smallest unit of data storage ES
Fragmentation
Each index has a plurality of tiles, each tile is a luncene, index fragmentation benefits: share index search pressure, fragmentation level of development and also supports split and distributed operation, can improve search and other processing efficiency
Backup
Copy of a slice backup is complete fragment benefits backup: when the primary slice fails or hang up, the backup can replace slicing operation, thereby improving the usability es, the backup fragment can also search operation, to share search pressures. ES when creating an index is created by default 5 slices, a backup, you can modify the number of slices can only be specified when creating the index, after the index creation can not change the number of fragments, while the backup is dynamic Modified
FIG ES database comparison:
Note: In ES6.0.0 and later versions, index creation can contain only one type of mapping. An index map multiple types of indexes created in the following versions 6.0.0 continue to play a role in the 6.0.0 version, but will be completely removed in 7.0.0 .
ES properties
Fast, easy to expand, elastic, flexible, simple, multi-lingual client, X-Pack, hadoop / spark Together, out of the box.
Distributed: Scale is very flexible
Full Text Search: Powerful full-text search capabilities based on the lucene;
Near real-time search and analysis: data into the ES, can achieve near real-time search, analysis can be polymerized
High Availability: fault tolerance, or failure to automatically discover new nodes, restructuring and rebalancing data
Free mode: ES dynamic mapping mechanism can automatically detect the structure and type of data, create indexes and searchable data.
RESTful API：JSON + HTTP
reference:
官网：
https://www.elastic.co/cn/products/elasticsearch
https://www.elastic.co