Description:
If you attempt to disable InnoDB in 5.6 by only specify these 2 settings (i.e., how it used to be done in the past, thus forgetting, or not knowing about the new "default-tmp-storage-engine" variable):
default-storage-engine=MyISAM
innodb=OFF
Then your instance will not start, and will report the following in the error log:
2014-11-08 18:47:28 13524 [Note] Plugin 'FEDERATED' is disabled.
2014-11-08 18:47:28 13524 [Warning] The option innodb (skip-innodb) is deprecated and will be removed in a future release
2014-11-08 18:47:28 13524 [Note] Plugin 'InnoDB' is disabled.
2014-11-08 18:47:28 13524 [ERROR] Unknown/unsupported storage engine: InnoDB
2014-11-08 18:47:28 13524 [ERROR] Aborting
...
You will not really have any idea why this keeps failing. You will search your config file repeatedly for an innodb_* option, but will not find one.
Thus this "Unknown/unsupported storage engine: InnoDB" is all due to the new "default-tmp-storage-engine" variable, which is probably not commonly known.
I propose adding an informational comment about which variable is responsible for the "Unknown/unsupported storage engine: InnoDB" message that is logged to the error log.
Of course, if you want to disable InnoDB in 5.6 successfully, you must specify:
default-storage-engine=MyISAM
default-tmp-storage-engine=MyISAM
innodb=OFF
How to repeat:
N/A
Suggested fix:
I propose adding an informational comment about which variable is responsible for the "Unknown/unsupported storage engine: InnoDB" message that is logged to the error log.
If we're able to add it like this, then every time such error is logged, it would be more informational, not just for this specific innodb_* option, but for any and all innodb_* options, in this case.
