MySQL server client architecture
The Client Layer in the MySQL architecture acts as the interface between users or applications and the MySQL Server. It allows users to communicate with the server by sending valid MySQL commands and queries through various means, such as the Command Prompt or Graphical User Interfaces (GUIs). This layer plays a crucial role in initiating and managing interactions with the database server.
Services of the Client Layer:
Connection Handling: The Client Layer handles the process of establishing connections between client applications and the MySQL Server. This involves creating network connections and managing communication channels. Clients can connect to the server using IP addresses, domain names, or "localhost" as the hostname. Once the connection is established, data can be exchanged between the client and the server.
Authentication: The Client Layer also manages the authentication process, ensuring that clients provide valid credentials before accessing the server. This is a critical security measure that prevents unauthorized access to the database. Clients provide their username and password, and the authentication mechanism validates this information against the server's user accounts.
Security: Security measures are implemented in the Client Layer to ensure data privacy and prevent unauthorized access. These measures include encryption of data transmission between client and server, preventing SQL injection attacks, and ensuring that clients only have access to the data and operations for which they are authorized.
Subcomponents of the MySQL Server Layer:
Connection Handler: The Connection Handler establishes and manages client connections. It authenticates clients, assigns dedicated threads to each connection, and tracks active connections.
Parser: The Parser interprets incoming SQL statements and checks their syntax and semantics for correctness. It converts queries into a format that the server can process.
Optimizer: The Optimizer analyzes parsed queries and determines the most efficient way to execute them. It considers available indexes, statistics, and other factors to create an optimized execution plan.
- Query Cache –
Query Cache stores the complete result set for inputted query statement. Even before Parsing , MySQL Server consult query cache . When client write a query , if the query written by client is identical in the cache then the server simply skip the parsing, optimization and even execution, it just simply display the output from the cache. - Buffer and Cache –
Cache and will buffer store the previous query or problem asked by user. When User write a query then it firstly goes to Query Cache then query cache will check that the same query or problem is available in the cache. If the same query is available then it will provide output without interfering Parser, Optimizer. - Table Metadata Cache –
The metadata cache is a reserved area of memory used for tracking information on databases, indexes, or objects. The greater the number of open databases, indexes, or objects, the larger the metadata cache size. - Key Cache –
A key cache is an index entry that uniquely identifies an object in a cache. By default, edge servers cache content based on the entire resource path and a query string.
Storage Layer:
This Storage Engine Layer of MySQL Architecture make it’s unique and most preferable for developer’s. Due to this Layer, MySQL layer is counted as the mostly used RDBMS and is widely used. In MySQL server, for different situations and requirement’s different types of storage engines are used which are InnoDB ,MyISAM , NDB ,Memory etc. These storage engines are used as pluggable storage engineer where tables created by user are plugged with them.- Query Cache –