mysqld

Start the MySQL database server

$ mysqld

$ mysqld --console

$ mysqld --log=[path/to/file.log]

$ mysqld --print-defaults

$ mysqld --defaults-file=[path/to/file]

$ mysqld --port=[port]

$ mysqld --verbose --help

mysqld [options]

--help
    Display help message and exit.

--basedir=path
    The base directory for the MySQL installation.

--datadir=path
    The path to the database root directory.

--port=port_number
    The TCP/IP port to listen on.

--socket=file_name
    The socket file to use for local connections.

--user=user_name
    The user account to run mysqld as.

--default-authentication-plugin=plugin_name
    The default authentication plugin used by the server.

--defaults-file=file_name
    Read options from the given file only.

--log-error=file_name
    File to log errors to.

--pid-file=file_name
    File for saving server process ID.

--bind-address=ip_address
    IP address for server to listen on.

The mysqld command starts the MySQL server. It is the core process that handles all database requests and manages the MySQL data directory.
mysqld is a multi-threaded server designed to handle multiple client connections concurrently. It uses various storage engines like InnoDB and MyISAM to manage data. Configuration is primarily controlled through the /etc/mysql/my.cnf file or command line options. Proper configuration is critical for performance, security, and data integrity. mysqld handles authentication, authorization, query processing, and data storage. It also manages backups, replication, and other administrative tasks. Without mysqld, the MySQL database system is non-functional. Correct operation is dependent on adequate memory and disk space resources. Monitoring mysqld's performance using tools like mysqladmin or monitoring solutions is important to proactively address performance issues and ensure stability.

Running mysqld as root is generally discouraged for security reasons. Using a dedicated MySQL user account is recommended. The MySQL server must have write access to the data directory and log files. Ensure proper resource allocation, like memory and file descriptors, for optimal performance. Check the log file for any errors after starting the server.

The MySQL server reads configuration options from several files in a specific order. The primary configuration file is typically /etc/mysql/my.cnf, but other files might be read depending on the system and user configuration.
Options specified later in the reading order override those specified earlier.

Securing the MySQL server is critical. Important security measures include setting strong passwords for all user accounts, restricting network access to the server, regularly applying security patches, and properly configuring firewall rules. Always keep your installation up-to-date to mitigate risk.

If mysqld fails to start, check the error log for details. Common causes include configuration errors, port conflicts, insufficient permissions, or a corrupted data directory. Restarting can also resolve many issues.

mysqld is the core component of the MySQL database system. Its development began in the mid-1990s by Michael 'Monty' Widenius and David Axmark. Originally designed for speed and reliability, it has evolved significantly over the years to incorporate features like transaction support, stored procedures, and replication. Different versions have introduced various performance optimizations, security enhancements, and new features. mysqld remains a popular choice for web applications and other database-driven systems.

mysql(1), mysqladmin(1), mysqldump(1)