Related commit: 85d5c3d
When attempting to send a hint, an exception might occur that results in
that hint being discarded (e.g. keyspace or table of the hint was
removed).
When such an exception is thrown, position of the hint will already be
stored in rps_set. We are only allowed to retain positions of hints that
failed to be sent and needed to be retried later. Dropping a hint is not
an error, therefore its position should be removed from rps_set - but
current logic does not do that.
Because of that bug, hint files with many discardable hints might cause
rps_set to grow large when the file is replayed. Furthermore, leaving
positions of such hints in rps_set might cause more hints than necessary
to be re-sent if some non-discarded hints fail to be sent.
This commit fixes the problem by removing positions of discarded hints
from rps_set.
Fixes#6433
0c5ac0da98