mysqldadmin hangs, making the whole shutdown process hang indefinitely

[stephen-hand-RTR]

Hi! We have an intermittent issue where the mysqladmin process is hanging when trying to shut down the mysql db.

Because there is no timeout waiting for this complete, it hangs indefinitely and won't move on to the other shutdown methods it should attempt in the stopInternal method.

Because the pid is hidden away, there is no alternative way to shut down the process when this happens, short of trying to identify with external processes (we are on Java 8 so no fancy process API) or use reflection hacks to try and get at the internals.

Could a shortish timeout be applied waiting for the mysqladmin process to complete so the shutdown logic can move on?

This is observed on wix-embedded-mysql 2.1.4, using MySQL version 5.6.24 on macOS Catalina 10.15.4

Alternatively, could a way be added to disable the JVM shutdown hook that stops the process? I believe the root cause of the hang is because the mysql shutdown has a race condition with logic in other shutdown hooks. If this shutdown hook could be disabled, I could eliminate the race condition in application logic

[stephen-hand-RTR]

Reproduced in latest version from maven (4.6.1)

[Lincong]

I also experienced this issue in com.wix:wix-embedded-mysql:4.6.1

[stephen-hand-RTR]

PR: #196