MySQL Bugs: #69519: InnoDB data dictionary LRU sizing through table_definition

Bug #69519	InnoDB data dictionary LRU sizing through table_definition_cache is undocumented
Submitted:	20 Jun 2013 4:20	Modified:	1 Jul 2013 7:43
Reporter:	Laurynas Biveinis (OCA)	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.6	OS:	Any
Assigned to:	Bugs System	CPU Architecture:	Any
Tags:	data dictionary, table_definition_cache

Description:
According to [1], InnoDB in 5.6 has a new feature where the data dictionary is organized as LRU with a length limit, which is governed by table_definition_cache setting.  But [2] does not document this, it only mentions the FRM cache.

[1] https://blogs.oracle.com/mysqlinnodb/entry/mysql_5_6_data_dictionary
[2] https://dev.mysql.com/doc/refman/5.6/en/server-system-variables.html#sysvar_table_definiti...

How to repeat:
Docs reading

Suggested fix:
Add text to [2] stating that table_definition_cache is used as a soft InnoDB data dictionary LRU length limit. If the limitations mentioned in [1] still exist (i.e. cannot evict tables in a FK relationship), then they should be documented too.

Hello Laurynas,

Thank you for the report.

Thanks,
Umesh

The information for table_definition_cache has been revised. The revised content will appear soon, in the next published documentation build. 

http://dev.mysql.com/doc/refman/5.6/en/server-system-variables.html#sysvar_table_definitio...
http://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_table_definitio...

Thank you for the bug report.

Thanks Daniel.

5.6 docs are pushed and I see extra quotes in https://dev.mysql.com/doc/refman/5.6/en/server-system-variables.html#sysvar_table_definiti...:

"For InnoDB, table_definition_cache is also
...
...
are not subject to eviction." 

These quotes are not me quoting the docs but literal quotes on the page. Should these be removed?

Thanks for the catch, Laurynas. I removed the quotes this morning. The revisions will appear with the next published doc build.