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:
http://dev.mysql.com/doc/refman/8.0/en/forcing-innodb-recovery.html
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
terribly wrong...
stack_bottom = 0 thread_stack 0x46000
/usr/sbin/mysqld(my_print_stacktrace(unsigned char const*, unsigned long)+0x3c) [0x556631e3bf4c]
/usr/sbin/mysqld(handle_fatal_signal+0x303) [0x556630d81fe3]
/lib/libpthread.so.0(+0x14570) [0x7f5905ba4570]
/lib/libc.so.6(gsignal+0x141) [0x7f590528edf1]
/lib/libc.so.6(abort+0x121) [0x7f5905278535]
/usr/sbin/mysqld(+0xe11787) [0x556630aef787]
/usr/sbin/mysqld(ib::fatal::~fatal()+0xcd) [0x55663211faad]
/usr/sbin/mysqld(srv_error_monitor_thread()+0xa45) [0x5566320b3b75]
/usr/sbin/mysqld(std::thread::_State_impl<std::thread::_Invoker<std::tuple<Runnable, void (*)()> > >::_M_run()+0xb5) [0x556631fc1b75]
/usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/libstdc++.so.6(+0xd0690) [0x7f5905654690]
/lib/libpthread.so.0(+0x83a7) [0x7f5905b983a7]
/lib/libc.so.6(clone+0x3f) [0x7f590535afaf]
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.