percona-discussion team mailing list archive

[MARK CALLAGHAN <mdcallag@xxxxxxxxx>]

On Thu, Apr 9, 2009 at 12:26 PM, Vadim Tkachenko <vadim@xxxxxxxxxxx> wrote:
> MARK ,
>
>
> This is rw_lock, so no output in SHOW MUTEX STATUS.
>
> But in SHOW INNODB STATUS it fills several screens in output.

I forgot about that. We fixed innodb_mutex_show_status in our branch
to display contention for both. It is an easy change to make. Another
good change is to not return data for mutexes and rw-locks with no
contention.

>
>
>
> MARK CALLAGHAN wrote:
>> On Thu, Apr 9, 2009 at 11:55 AM, Evgeniy Stepchenko
>> <evgeny.stepchenko@xxxxxxxxxxx> wrote:
>>> ** Changed in: percona-xtradb
>>>   Importance: Undecided => Medium
>>>
>>> ** Changed in: percona-patches
>>>   Importance: Undecided => Medium
>>>
>>> --
>>> Adaptive search scalability
>>> https://bugs.launchpad.net/bugs/331659
>>> You received this bug notification because you are a member of Percona
>>> developers, which is the registrant for Percona patches.
>>>
>>> Status in Patches for MySQL by Percona: New
>>> Status in Percona XtraDB Storage Engine for MySQL: New
>>>
>>> Bug description:
>>> During some workloads I see a lot of output
>>> --Thread 1164450128 has waited at btr0sea.c line 1383 for 0.00 seconds the semaphore:
>>> X-lock on RW-latch at 0x2aaaac50e0b8 created in file btr0sea.c line 139
>>> a writer (thread id 1164450128) has reserved it in mode  wait exclusive
>>>  number of readers 1, waiters flag 1
>>>  Last time read locked in file btr0sea.c line 746
>>>  Last time write locked in file btr0sea.c line 1383
>>>  though the waits are very small though -- 0.00
>>>
>>> What we can do there ?
>>
>> Does SHOW MUTEX STATUS report a lot of contention for it?
>>
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>>
>>
>>
>
>
> --
> Vadim Tkachenko, CTO
> Percona Inc.
> ICQ: 369-510-335, Skype: vadimtk153, Phone +1-888-401-3403
> MySQL Performance Blog - http://www.mysqlperformanceblog.com
> MySQL Consulting http://www.percona.com/
>
>  Attend the 2009 Percona Performance Conference
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>



-- 
Mark Callaghan
mdcallag@xxxxxxxxx