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[Yasufumi Kinoshita <yasufumi.kinoshita@xxxxxxxxxxx>]

The entry of table_cache is not unique to its table name. And the entry of dictionary is unique to its table name.

The each handler in the table_cache opens the dictionary entry by its table name.
Which opens and uses the dictionary entry are not only handlers.
Internally, InnoDB uses the entries of some system tables.
And recovery process or purge process also uses entries of the tables to use.

We cannot remove entry of the table used.
So sometimes the dictionary size may exceed dict_size_limit.
(like relation between the variable "table_cache" and status "Open_tables")
-- 
https://code.launchpad.net/~percona-dev/percona-patches/dict-size-limit/+merge/3119
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