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:"
The performance schema however is less intuitive to use, and, as was
noted in the MySQL announcement of the removal, doesn't yet include
spinning information.
There's a post on Percona's blog that looks at getting similar
information using the Performance Schema:
http://www.percona.com/blog/2015/01/06/getting-mutex-information-from-mysqls-performance_schema/
Much depends on what happens with XtraDB's implementation, but I
wouldn't be in favour of just removing it without notice, as happened in
MySQL 5.7. It should at least be deprecated.
ian
_______________________________________________
Mailing list: https://launchpad.net/~maria-discuss
Post to : maria-discuss@lists.launchpad.net
Unsubscribe : https://launchpad.net/~maria-discuss
More help : https://help.launchpad.net/ListHelp
