• tablespace definition cache partition : Stores tablespace definition objects. The tablespace_definition_cache  option sets a limit for the number of tablespace definition objects that can be stored in the dictionary object cache. The default value is 256. 

• schema definition cache partition : Stores schema definition objects. The schema_definition_cache  option sets a limit for the number of schema definition objects that can be stored in the dictionary object cache. The default value is 256. 

• table definition cache partition : Stores table definition objects. The object limit is set to the value of max_connections , which has a default value of 151. 

The table definition cache partition exists in parallel with the table definition cache that is configured using the table_definition_cache  configuration option. Both caches store table definitions but serve different parts of the MySQL server. Objects in one cache have no dependence on the existence of objects in the other. 

• stored program definition cache partition : Stores stored program definition objects. The stored_program_definition_cache  option sets a limit for the number of stored program definition objects that can be stored in the dictionary object cache. The default value is 256. 

The stored program definition cache partition exists in parallel with the stored procedure and stored function caches that are configured using the stored_program_cache  option. 

The stored_program_cache  option sets a soft upper limit for the number of cached stored procedures or functions per connection, and the limit is checked each time a connection executes a stored procedure or function. The stored program definition cache partition, on the other hand, is a shared cache that stores stored program definition objects for other purposes. The existence of objects in the stored program definition cache partition has no dependence on the existence of objects in the stored procedure cache or stored function cache, and vice versa. 

• character set definition cache partition : Stores character set definition objects and has a hardcoded object limit of 256. 

• collation definition cache partition : Stores collation definition objects and has a hardcoded object limit of 256. 

For information about valid values for dictionary object cache configuration options, refer to Section 5.1.8, “Server System Variables” . 

## 14.5 INFORMATION_SCHEMA and Data Dictionary Integration 

With the introduction of the data dictionary, the following INFORMATION_SCHEMA  tables are implemented as views on data dictionary tables: 

• CHARACTER_SETS 

• CHECK_CONSTRAINTS 

• COLLATIONS 

• COLLATION_CHARACTER_SET_APPLICABILITY 

• COLUMNS 

• COLUMN_STATISTICS 

• EVENTS 

