Cluster_Management.md

graph LR
    domain["domain"]
    br["br"]
    cdc["cdc"]
    tidb_kv["tidb.kv"]
    planner["planner"]
    ddl["ddl"]
    br -- "Queries for a consistent view of the schema" --> domain
    br -- "Reads large volumes of key-value data" --> tidb_kv
    cdc -- "Monitors for schema changes" --> domain
    cdc -- "Reads committed data changes from the storage layer's logs" --> tidb_kv
    planner -- "Consults for schema information" --> domain
    ddl -- "Orchestrate and persist schema changes" --> domain

Loading

Details

The Cluster Management subsystem is composed of operational tools and a central metadata component that enables their function. The following six components are fundamental to its architecture and its interaction with the core database.

domain

Acts as the central authority for cluster-wide metadata. It caches and manages schema information, versions, and coordinates online DDL jobs, serving as the bridge between the database core and management tools.

Related Classes/Methods:

• domain/

br

Manages the creation of consistent, distributed snapshots for backup and restore operations. It coordinates with the underlying storage to capture a transactionally consistent view of the data across the cluster.

Related Classes/Methods:

• br/

cdc

Captures and streams row-level data changes (INSERT, UPDATE, DELETE) in real-time to downstream systems. It enables data integration by tapping into the underlying storage logs.

Related Classes/Methods:

• cdc/

tidb.kv

Provides the primary abstraction layer for accessing the distributed key-value data in the underlying storage engine (TiKV). It is optimized for the high-throughput reads required by br and cdc.

Related Classes/Methods:

• tidb/kv/

planner

Responsible for parsing and optimizing SQL queries. It is a critical consumer of the domain component, relying on it for the schema information necessary to build efficient query execution plans.

Related Classes/Methods:

• planner/

ddl

Manages the execution of Data Definition Language (DDL) statements. It interacts directly with the domain component to apply and track schema changes across the distributed environment.

Related Classes/Methods:

• ddl/

FAQ