maria-discuss team mailing list archive

[Gordan Bobic <gordan.bobic@xxxxxxxxx>]

I'd look at 10.3.28, there seem to be a few locking related fixes in it.

On Tue, Mar 16, 2021 at 2:10 PM Conor Murphy <conor_mark_murphy@xxxxxxxxxxx>
wrote:

> Hi,
>
> I had seen some discussions about this and tried setting
>
> innodb_adaptive_hash_index = OFF
>
> But it didn't resolve the problem.
>
> /Conor
>
> ------------------------------
> *From:* Gordan Bobic <gordan.bobic@xxxxxxxxx>
> *Sent:* Tuesday 16 March 2021 14:06
> *To:* Conor Murphy <conor_mark_murphy@xxxxxxxxxxx>
> *Cc:* maria-discuss@xxxxxxxxxxxxxxxxxxx <maria-discuss@xxxxxxxxxxxxxxxxxxx
> >
> *Subject:* Re: [Maria-discuss] Problem with InnoDB: Semaphore wait after
> upgrading to 10.3.27
>
> Just a hunch, but have you tried disabling AHI?
> innodb_adaptive_hash_index = 0
>
> I vaguely remember having a similar problem a while back and it was AHI
> related.
>
> I hit a number of spurious locking issues in 10.4.17 that seem to have
> been resolved in 10.4.18. It is plausible that some of them also affected
> the 10.3 branch and were similarly resolved recently. Some of them
> manifested similarly until I mitigated them by setting the
> lock_wait_timeout to 30 on the basis that it was better for a query to give
> up and be retried than to be blocking things for longer. I haven't seen it
> come up since the 10.4.18 upgrade. 10.4.18 change log has quite a few fixes
> for various locking issues.
>
>
> On Tue, Mar 16, 2021 at 1:58 PM Conor Murphy <
> conor_mark_murphy@xxxxxxxxxxx> wrote:
>
> Hi,
>
> We have a handful of servers running MariaDB 10.3. We noticed issues on
> two of them where we were getting issues like "InnoDB: A long semaphore
> wait:--Thread 140602802394880 has waited at dict0stats.cc line 1969 for
> 241.00 seconds the semaphore:" and crashes like "ERROR] [FATAL] InnoDB:
> Semaphore wait has lasted > 600 seconds. We intentionally crash the server
> because it appears to be hung.210215  7:14:24 [ERROR] mysqld got signal 6 ;"
>
> Turned out that these two servers were running 10.3.27 whereas the others
> were running 10.3.17. After downgrading the two problem servers to 10.3.17,
> all the issues with InnoDB semaphores stopped.
>
> Any ideas on how to track down what change between 10.3.17 to 10.3.27
> might be causing this problem?
>
> Thanks,
> Conor
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