innodb_buffer_pool_chunk_size

The innodb_buffer_pool_chunk_size variable sets the chunk size for InnoDB buffer pool resizing operations. Tuning this setting may change the buffer pool size.

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innodb_buffer_pool_chunk_size is a variable closely related to innodb_buffer_pool_size and innodb_buffer_pool_instances.

The buffer pool is reduced or enlarged by the chunk size set by innodb_buffer_pool_chunk size. Within the buffer pool, there can be multiple instances set by innodb_buffer_pool_instances. Instances are divided into chunks.

For example, consider these effective values: innodb_buffer_pool_size of 2 GiB, innodb_buffer_pool_instances of 8, and innodb_buffer_pool_chunk_size of 128 MiB. That is 16 chunks in total, or 2 chunks per instance.

Notice how each variable has an impact on the succeeding variable.

In Oracle MySQL 8.0 and 8.4, innodb_buffer_pool_chunk_size is a global, non-dynamic startup setting. Change it in the server startup configuration and restart MySQL; opening a new connection does not apply the change. Before a change, calculate the effect of chunk size and buffer pool instances on the effective buffer pool size, and verify the values after restart. innodb_buffer_pool_size is a separate variable that can be resized online, subject to operational constraints.

The effective innodb_buffer_pool_size is adjusted in increments based on innodb_buffer_pool_instances multiplied by innodb_buffer_pool_chunk_size. Check the effective values and available memory when planning a configuration change.