Hints destined for some other node can only be drained after the other
node is no longer a replica of any vnode or tablet. In case when tablets
are present, a node might still technically be a replica of some tablets
after it moved to left state. When it no longer is a replica of any
tablet, it becomes "released" and storage service generates a
notification about it. Hinted handoff listens to this notification and
kicks off draining hints after getting it.
The current implementation of the "released" notification would trigger
every time raft topology state is reloaded and a left node without any
tokens is present in the raft topology. Although draining hints is
idempotent, generating duplicate notifications is wasteful and recently
became very noisy after in 44de563 verbosity of the draining-related log
messages have been increased. The verbosity increase itself makes sense
as draining is supposed to be a rare operation, but the duplicate
notification bug now needs to be addressed.
Fix the duplicate notification problem by passing the list of previously
released nodes to the `storage_service::raft_topology_update_ip`
function and filtering based on it. If this function processes the
topology state for the first time, it will not produce any
notifications. This is fine as hinted handoff is prepared to detect
"released" nodes during the startup sequence in main.cc and start
draining the hints there, if needed.
Fixes: #28301
Refs: #25031
d28c841fa9