17.8.12 Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server

When the server is started with --innodb-dedicated-server, InnoDB automatically calculates values for and sets the following system variables:

• innodb_buffer_pool_size

• innodb_redo_log_capacity

Note

innodb_redo_log_capacity supersedes both innodb_log_file_size and innodb_log_files_in_group, which were set by --innodb-dedicated-server in older versions of MySQL, but which have since been deprecated. You should expect innodb_log_file_size and innodb_log_files_in_group to be removed in a future version of MySQL.

In MySQL 8.0, innodb_flush_method was also set automatically by this option, but in MySQL 8.4, this is no longer the case.

You should consider using --innodb-dedicated-server only if the MySQL instance resides on a dedicated server where it can use all available system resources—for example, if you run MySQL Server in a Docker container or dedicated VM that runs MySQL only. using --innodb-dedicated-server is not recommended if the MySQL instance shares system resources with other applications.

The value for each affected variable is determined and applied by --innodb-dedicated-server as described in the following list:

• innodb_buffer_pool_size

  Buffer pool size is calculated according to the amount of memory detected on the server, as shown in the following table:

  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 calculated according to the number 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.

• innodb_log_file_size (deprecated)

  Log file size is set according to the automatically configured buffer pool size, as shown in the following table:

  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 determined according to the automatically configured buffer pool size, as shown in the following table:

  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 value for innodb_log_files_in_group value is 2; this lower limit is enforced if the rounded buffer pool size value is less than this number.

If one of the variables listed previously is set explicitly in an option file or elsewhere, this explicit value is used, and a startup warning similar to this one 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.

Setting one variable explicitly does not prevent the automatic configuration of other options.

If the server is started with --innodb-dedicated-server and innodb_buffer_pool_size is set explicitly, variable settings 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.

Note

Automatic configuration settings are applied by --innodb-dedicated-server only when the MySQL server is started. If you later set any of the affected variables explicitly, this overrides its predetermined value, and the value that was explicitly set is applied. Setting one of these variables to DEFAULT causes it to be set to the actual default value as shown in the variable's description in the Manual, and does not cause it to revert to the value set by --innodb-dedicated-server. The corresponding system variable innodb_dedicated_server is changed only by starting the server with --innodb-dedicated-server (or with --innodb-dedicated-server=ON or --innodb-dedicated-server=OFF); it is otherwise read-only.