A TiKV Node is a physical node in the cluster, which might be a virtual machine, a container, etc. Within each Node, there can be one or more stores.

The Node, Store, and Region regularly report their status to the Placement Driver.

Placement Driver (PD)

A replica of a Region is called a peer. Multiple peers of the same Region replicate data via the Raft consensus algorithm.

Raft

Data is distributed across TiKV instances via the Raft consensus algorithm, which is based on the (“In Search of an Understandable Consensus Algorithm”) from Diego Ongaro and .

Store

A Store is an instance of a TiKV server in which multiple peers are stored.

TiKV provides transactions that allow you to read and write across any keys with Snapshot Isolation regardless of the physical placement of the Region. TiKV also provides the pessimistic transactions that are semantically similar to in SQL.