MySQL Bugs: #109074: Question about MySQL5.6/5.7 on ARM.

Bug #109074	Question about MySQL5.6/5.7 on ARM.
Submitted:	14 Nov 2022 3:25	Modified:	14 Nov 2022 13:41
Reporter:	Qingda Hu	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server	Severity:	S3 (Non-critical)
Version:	5.6, 5.7	OS:	Any
Assigned to:		CPU Architecture:	ARM

Description:
As far as we know, the CPUs based on the ARM architecture become more and more popular today. Even in data centers / clouds, some companies begin to provide ARM CPUs for users to save CPU/energy cost, such as AWS graviton. 

From the url page (Supported Platforms: MySQL Database, https://www.mysql.com/support/supportedplatforms/database.html), we see only 8.0 support ARM 64. Therefore, I am confused whether MySQL support MySQL 5.6 and MySQL 5.7 on ARM CPUs or not. 

In other words, what are the problems if we run MySQL 5.6 / 5.7 in ARM CPUs. I have see a bug report from Yibo Cai for 5.7 on ARM (Mysql deadlock and bugcheck on aarch64 under stress test, https://bugs.mysql.com/bug.php?id=94699), and this bug has already been fixed. 

Looking forward to receiving your comments.

How to repeat:
No bug found, just confused on supported platform.

As we known, compared to X86, ARM has a weak memory order. It is dangerous if we do not use the correct memory barrier, especially in some lock-free algorithms and some cases using atomic operations like EventMutex. Besides the bug report from Yibo Cai (https://bugs.mysql.com/bug.php?id=94699), I am worried there is other similar problems in MySQL 5.6 / 5.7. 

Thanks and looking forward to your reply!

Hi Mr. Hu,

Thank you for your bug report.

However, 5.6 is not maintained any more and 5.7 is only in the maintenance mode. That means that we support fully ARM in 8.0-only.

Regarding ARM CPU, although, yes, it has a weak memory model, it has dependency ordering , so we found out that 8.0 did not require too many changes .....

Not a bug ......