(mysql.info.gz) Key cache block size
Info Catalog
(mysql.info.gz) Index preloading
(mysql.info.gz) MyISAM key cache
(mysql.info.gz) Key cache restructuring
7.4.6.5 Key Cache Block Size
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MySQL 4.1 introduces a new `key_cache_block_size' variable on a per-key
cache basis. This variable specifies the size of the block buffers for
a key cache. It is intended to allow 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.
Currently, you cannot control the size of the index blocks in a table.
This size is set by the server when the `.MYI' index file is created,
depending on the size of the keys in the indexes present in the table
definition. In most cases, it is set equal to the I/O buffer size. In
the future, this will be changed and then `key_cache_block_size'
variable will be fully employed.
Info Catalog
(mysql.info.gz) Index preloading
(mysql.info.gz) MyISAM key cache
(mysql.info.gz) Key cache restructuring
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