This statement analyzes and stores the key distribution for a table.
During the analysis, the table is locked with a read lock.  This works on
MyISAM and BDB tables and (as of MySQL 4.0.13) InnoDB
tables. For MyISAM tables, this
statement is equivalent to using myisamchk -a.

MySQL uses the stored key distribution to decide the order in which
tables should be joined when you perform a join on something other than a
constant.
