Comment 4 for bug 576041

Yasufumi,

This is MySQL 5.1.45-rel10

Please run the test case I have suggested altering tables to Innodb. I trust
you can just do it with one table in the loop. If you can't repeat it I
will get more information. I did not bother because It breaks in couple of
different ways and I'd like you to stress test this functionality to ensure
it works well - there may be multiple issues with it.

On Wed, May 5, 2010 at 6:48 PM, Yasufumi Kinoshita <
<email address hidden>> wrote:

> Peter,
> Which version do you use?
>
> And, this information shows "who waits" only.
> I 'd like to know is "who make them wait" rather than above.
>
> So, I need stacktrace at the time.
> I cannot analyze because information is shortage.
>
> --
> innodb_buffer_pool_pages_index performance
> https://bugs.launchpad.net/bugs/576041
> You received this bug notification because you are a direct subscriber
> of the bug.
>
> Status in Percona Server with XtraDB: Triaged
>
> Bug description:
> Accerssing innodb_buffer_pool_pages_index can be very slow under load,
> it also can cause certain mutexes to be locked for long time causing server
> stall and potentially server crash (if locks are held more than allowed by
> Innodb watchdog)
>
> ----------
> SEMAPHORES
> ----------
> OS WAIT ARRAY INFO: reservation count 4112, signal count 4016
> --Thread 1235454272 has waited at buf/buf0lru.c line 2046 for 127.00
> seconds the semaphore:
> Mutex at 0xde2020 '&buf_pool_mutex', lock var 1
> waiters flag 1
> --Thread 1247275328 has waited at buf/buf0lru.c line 698 for 127.00 seconds
> the semaphore:
> Mutex at 0xde2020 '&buf_pool_mutex', lock var 1
> waiters flag 1
> --Thread 1214474560 has waited at buf/buf0flu.c line 1077 for 127.00
> seconds the semaphore:
> Mutex at 0xde2020 '&buf_pool_mutex', lock var 1
> waiters flag 1
> --Thread 1245944128 has waited at row/row0purge.c line 543 for 122.00
> seconds the semaphore:
> Mutex at 0x6812220 '&dict_sys->mutex', lock var 1
> waiters flag 1
> Mutex spin waits 24624, rounds 144847, OS waits 3454
> RW-shared spins 813, OS waits 483; RW-excl spins 48, OS waits 154
> Spin rounds per wait: 5.88 mutex, 22.41 RW-shared, 104.08 RW-excl
>
> To unsubscribe from this bug, go to:
> https://bugs.launchpad.net/percona-server/+bug/576041/+subscribe
>

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