buffer pool instance
Any of the multiple regions into which the buffer pool can be divided, controlled by the innodb-buffer-pool-instances configuration option. The total memory size specified by the innodb_buffer_pool_size is divided among all the instances. Typically, multiple buffer pool instances are appropriate for systems devoting multiple gigabytes to the InnoDB buffer pool, with each instance 1 gigabyte or larger. On systems loading or looking up large amounts of data in the buffer pool from many concurrent sessions, having multiple instances reduces the contention for exclusive access to the data structures that manage the buffer pool.
See also buffer pool.