MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
It is possible to specify the size of the block buffers for an
individual key cache using the
key_cache_block_size
variable. This permits tuning of the performance of I/O
operations for index files.
The best performance for I/O operations is achieved when the size of read buffers is equal to the size of the native operating system I/O buffers. But setting the size of key nodes equal to the size of the I/O buffer does not always ensure the best overall performance. When reading the big leaf nodes, the server pulls in a lot of unnecessary data, effectively preventing reading other leaf nodes.
To control the size of blocks in the .MYI
index file of MyISAM
tables, use the
--myisam-block-size
option at
server startup.