-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Guido,
On 12/5/18 10:46, Jäkel, Guido wrote: >> Does it really ? If some tomcat code is at that time processing >> a client POST request, which potentially modifies data on the >> server (or a back-end database), is ditto tomcat code "informed" >> of the JVM shutdown, and does it have time to interrupt the >> processing in some predictable/recoverable way ? > > In no other way than a Tomcat worker get informed about a Tomcat > shutdown if you trigger this event e.g. by the shutdown port > mechanism or JXM. OT a feature of Tomcat is that it will first > stop accepting new requests by the connectors and let the servlet > containers stop the applications afterwards. Therefore, a started > request will be finished. And after all request workers are idle, > the worker pool will terminate. > > If you send a signal to a process, nothing is "interrupted" but > just a consumer in the process get signaled - that's why it's > called this way. And that's the reason why a process might not stop > if you send a SIGTERM to it. It's just a request to please the > process to terminate by itself. Some signals are handled outside > the process, for simplification let's say by the process scheduler. > If one send a SIGKILL, the scheduler will "hard kill" the process > (and it's threads) at any point of execution path and just recover > the reserved resources. This is exactly correct. It's often surprising to people when they find out that a SIGTERM can initiate a "graceful" shutdown of a running JVM. I think most people thing that SIGTERM and SIGKILL are roughly the same thing. It's an instructive thought-experiment to consider that most *NIX-style init systems send SIGTERM signals to all process as they are shutting-down the operating system. This doesn't "terminate" the processes (as the signal name might suggest), but rather "requests that they self-terminate" where the process gets to decide how to shut itself down. It's only SIGKILL (or some of the hardware-generated signals like SIGBUS) that will simply end a process without any notification or anything else. - -chris -----BEGIN PGP SIGNATURE----- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAlwH9KIACgkQHPApP6U8 pFic6Q/9EYOtfxeUnkLX76joeNYShpdlWhmATzHCHeW/jalATsrtZood0xVLzJze Aw9yvYx1mdeOeJ0UyD9puv4/cOnI9dEsKgO4FMu3TjO6S9ern3sgK8bgJlVqI1Tf dI4STGhfRDS0L8E6a6oyWDPpCmRgtLre67KFQFd6aAczSe9YxzSlLEp+eyBv3DXa RjC/TDDHPi+dnJJKB7geOdZgv/Apso+z1c2CpZKGvud1m93S994NY2hQxuRTEXZ5 q6TWd/XarsuvcEOoU+4Jg6WX0ccqNF3AaTz5N0uAMcI+ZKAsc+6nQH65staOYEn3 9OFmBjNTZxXAD+7iJz2u2sk6REgHyvyhueqwwLDqM+FB4e0eQgLoq6dOhR0GegUD IHAAgJ7jcpy5wOGZPHFg6DBONg+eiWHaRIrCQZQmS8OcALK5ZsasRHnWit7HdL4k GJcC1jnXmIiK6ukRCil/GKusYVXvkDAhKkKcJ/Mwq2RqHamM4Gi2zkwKvq8oLnj8 XvW2SStOneVyw2o7e5KxfVOGRw+hmjflKh9XhzN4cmjsFzgK1uCaEU9SidmwC27c 8nXeZVBZYdLWW7Fixcisr5WZWSxYTJYOgQAfV4w4iP+q/kJYlz9af1VOeh584Wrd PMzldJcFQ9sYAWe5IF8g+uO9rlP31fjY806t6oovjlbq7BRSZxE= =pzVr -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
