Re: Relationship between MySQL variable open_files_limit and table_open_cache

[Rick James]

open_files_limit comes from an OS setting. (Which OS are you using?) table_open_cache needs to be less than that.

Two things come to mind that could cause that error:

* Failure to `DEALLOCATE PREPARE` in a stored procedure.

* PARTITIONed table(s) with a large number of partitions and innodb_file_per_table = ON. Recommend not having more than 50 partitions in a given table (for various reasons). (When "Native Partitions" become available, this advice may change.)

The obvious workaround is to set increase the OS limit:
To allow more files, change ulimit or /etc/security/limits.conf or in sysctl.conf (kern.maxfiles & kern.maxfilesperproc) or something else (OS dependent).
Then increase `open_files_limit` and `table_open_cache`.

As of 5.6.8, open_files_limit is auto-sized based on `max_connections`, but it is OK to change it from the default.