maria-discuss team mailing list archive

[Stewart Smith <stewart@xxxxxxxxxxxxxxxx>]

Ian Gilfillan <ian@xxxxxxxxxxx> 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

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