17.8.12 Enabling Automatic Configuration for a Dedicated MySQL Server

When innodb_dedicated_server is enabled, InnoDB automatically configures the following variables:

• innodb_buffer_pool_size

• innodb_redo_log_capacity

  Note

  innodb_log_file_size and innodb_log_files_in_group are deprecated, and are superseded by innodb_redo_log_capacity.

Only consider enabling innodb_dedicated_server if the MySQL instance resides on a dedicated server where it can use all available system resources. For example, consider enabling innodb_dedicated_server if you run MySQL Server in a Docker container or dedicated VM that only runs MySQL. Enabling innodb_dedicated_server is not recommended if the MySQL instance shares system resources with other applications.

The information that follows describes how each variable is automatically configured.

• innodb_buffer_pool_size

  Buffer pool size is configured according to the amount of memory detected on the server.

  Table 17.8 Automatically Configured Buffer Pool Size

  Detected Server Memory	Buffer Pool Size
  Less than 1GB	128MB (the default value)
  1GB to 4GB	detected server memory * 0.5
  Greater than 4GB	detected server memory * 0.75

  
  

• innodb_redo_log_capacity

  Redo log capacity is configured according to the amount of logical processors available on the server. The formula is (number of available logical processors / 2) GB, with a maximum dynamic default value of 16 GB.

  Note

  Before MySQL 8.4, this value was based on available memory instead of available logical processors.

• innodb_log_file_size (deprecated)

  Log file size is configured according to the automatically configured buffer pool size.

  Table 17.9 Automatically Configured Log File Size

  Buffer Pool Size	Log File Size
  Less than 8GB	512MB
  8GB to 128GB	1024MB
  Greater than 128GB	2048MB

  
  

• innodb_log_files_in_group (deprecated)

  The number of log files is configured according to the automatically configured buffer pool size.

  Table 17.10 Automatically Configured Number of Log Files

  Buffer Pool Size	Number of Log Files
  Less than 8GB	round(buffer pool size)
  8GB to 128GB	round(buffer pool size * 0.75)
  Greater than 128GB	64

  
  
  Note

  The minimum innodb_log_files_in_group value of 2 is enforced if the rounded buffer pool size value is less than 2GB.

If an automatically configured option is configured explicitly in an option file or elsewhere, the explicitly specified setting is used, and a startup warning similar to this is printed to stderr:

[Warning] [000000] InnoDB: Option innodb_dedicated_server is ignored for innodb_buffer_pool_size because innodb_buffer_pool_size=134217728 is specified explicitly.

Explicit configuration of one option does not prevent the automatic configuration of other options.

If innodb_dedicated_server is enabled and innodb_buffer_pool_size is configured explicitly, variables configured based on buffer pool size use the buffer pool size value calculated according to the amount of memory detected on the server rather than the explicitly defined buffer pool size value.

Automatically configured settings are evaluated and reconfigured if necessary each time the MySQL server is started.