fpmmm Triggers and Rules

<p>InnoDB plugin is enabled.</p>

MySQL (InnoDB, PBXT, NDB, TokuDB) support Foreign Keys to show relatations between tables. Those relations can be enforced through Foreign Key Constraints.

Foreign Key Constraint Errors are always either a bug in your application (which should be fixed) or inconsistencies in your data (which should be fixed) or both (first fix the bug in the application, then clean-up your data).

Foreign Key Constraint Errors can be found with the following command:

The number of table definitions (SHOW CREATE TABLE\G) that can be stored in the table definition cache (table_definition_cache). If you have a large number of tables (> 400) in your database instance, you should consider a larger table definition cache to increase your database throughput and decrease your query latency.

The Table Open Cache (table_open_cache or old name table_cache) is a cache to store file handles for all threads. The actual value of cache entries can be seen with the global status of open tables (Open_tables).
Increasing table_open_cache increases the number of file descriptors (open_files_limit) that MySQL requires.