Hello,
Why do we need «immediate»?
Is there real-world scenarios for it?
Can we do graceful or «save all possible data» shutdown always?
> 18 окт. 2022 г., в 10:59, Aleksandr Polovtsev <alexpolovt...@gmail.com>
> написал(а):
>
> Hello, dear Igniters!
>
> I'd like to propose a refactoring of the current Shutdown Policy mechanism.
> Currently, node shutdown is controlled by a bunch of flags and enums (I may
> be missing some of them):
>
> 1. ShutdownPolicy enum has only two entries and is basically a flag that
> dictates if we need to wait for the data to be backed up, so that we will
> not lose any data when the node goes offline.
> 2. "cancel" flag is passed to the stop method and indicates that all long
> running jobs should be interrupted. For example, it prevents the node
> performing a checkpoint on shutdown. I'm pretty sure this flag is nearly
> always set to "true", because it is used by the Shutdown Hook.
> 3. There are also a bunch of system properties that affect the shutdown:
> * IGNITE_PDS_SKIP_CHECKPOINT_ON_NODE_STOP - disables checkpoints on
> node stop, which heavily correlates with the "cancel" flag.
> * IGNITE_WAIT_FOR_BACKUPS_ON_SHUTDOWN - deprecated and duplicates the
> ShutdownPolicy enum
> * IGNITE_NO_SHUTDOWN_HOOK - disables the shutdown hook. I don't know if
> it is really useful.
>
> I think that this approach is counter intuitive and would like to
> incorporate all aforementioned flags into the ShutdownPolicy enum. For
> example, it can look as follows:
>
> public enum ShutdownPolicy {
> IMMEDIATE // Stops the node and cancels all running jobs
> GRACEFUL // Stops the node, does not cancel running jobs and waits for
> backups
> GRACEFUL_NO_BACKUPS // Stops the node, does not cancel running jobs,
> does not wait for backups
> }
>
> After that, the "cancel" flag and all corresponding properties can be
> removed (apart from the IGNITE_NO_SHUTDOWN_HOOK, if it is still needed).
>
> Does this make sense? What do you think?
>
> --
> With regards,
> Aleksandr Polovtsev
