Ian Gilfillan <ian@mariadb.org> writes:
On 01/01/2015 06:13 PM, Federico Razzoli wrote:
Morgan Tocker asked the community's opinions about SHOW ENGINE INNODB MUTEX: http://www.tocker.ca/2013/11/28/show-engine-innodb-mutex.html
Despite these opinions, as Valerii Kravchuk notes on Facebook, the command disappeared in the latest 5.7 release. He also notes that the command has never been deprecated (!).
Question is: will MariaDB preserve this command? Frankly, I don't know any other convenient way to obtain the same information... The main reason in favour of its removal in MySQL seems to be this point:
"The InnoDB mutex code was recently refactored as part of our server cleanup. After refactoring, the InnoDB code can now mix several mutex types internally including spin locks, system mutexes (POSIX) and InnoDB home brewed ones. The display output for |SHOW ENGINE INNODB MUTEX| doesn't really account for these differences in its status column. Grouping all mutex types together becomes less intuitive, and would require either some change to the output, or a coarse (inaccurate) mixing of the types:"
/usr/bin/perf works brilliantly for tracking spinlocks with zero overhead when not running. -- Stewart Smith