Every once in a while, mysql appears to hang and then some self-monitoring process crashes the server.
Here's a snippet of the log
InnoDB: ###### Diagnostic info printed to the standard error stream
2021-09-30T08:46:41.703931Z 0 [ERROR] [MY-012872] [InnoDB] [FATAL] Semaphore wait has lasted > 600 seconds. We intentionally crash the server because it appe
ars to be hung.
2021-09-30T08:46:41.705066Z 0 [ERROR] [MY-013183] [InnoDB] Assertion failure: ut0ut.cc:552 thread 140013884413696
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: about forcing recovery.
08:46:41 UTC - mysqld got signal 6 ;
Most likely, you have hit a bug, but this error can also be caused by malfunctioning hardware.
Thread pointer: 0x0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
stack_bottom = 0 thread_stack 0x46000
/usr/sbin/mysqld(my_print_stacktrace(unsigned char const*, unsigned long)+0x3c) [0x556631e3bf4c]
/usr/sbin/mysqld(std::thread::_State_impl<std::thread::_Invoker<std::tuple<Runnable, void (*)()> > >::_M_run()+0xb5) [0x556631fc1b75]
This is version 8.0.20 on 64-bit Gentoo Linux with kernel 4.19.118.
We aren't presently changing any data on the databases, only users reading from them.