(mysql.info.gz) Key cache restructuring

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(mysql.info.gz) Key cache block size

(mysql.info.gz) MyISAM key cache

 
 7.4.6.6 Restructuring a Key Cache
 .................................
 
 A key cache can be restructured at any time by updating its parameter
 values.  For example:
 
      mysql> SET GLOBAL cold_cache.key_buffer_size=4*1024*1024;
 
 If you assign to either the `key_buffer_size' or `key_cache_block_size'
 key cache component a value that differs from the component's current
 value, the server destroys the cache's old structure and creates a new
 one based on the new values.  If the cache contains any dirty blocks,
 the server saves them to disk before destroying and re-creating the
 cache. Restructuring does not occur if you set other key cache
 parameters.
 
 When restructuring a key cache, the server first flushes the contents
 of any dirty buffers to disk. After that, the cache contents become
 unavailable.  However, restructuring does not block queries that need
 to use indexes assigned to the cache.  Instead, the server directly
 accesses the table indexes using native filesystem caching.  Filesystem
 caching is not as efficient as using a key cache, so although queries
 will execute, a slowdown can be anticipated.  Once the cache has been
 restructured, it becomes available again for caching indexes assigned
 to it, and the use of filesystem caching for the indexes ceases.
 

Info Catalog

(mysql.info.gz) Key cache block size

(mysql.info.gz) MyISAM key cache