I came across an interesting scenario that led to the discovery of this bug:
if a keyspace is created before a snapshot cycle and before termsig/bgsave,
and then the snapshot cycle runs, then the subsequent runs of bgsave/termsig
would fail. The reason behind this interesting bug turns out to be rather
trivial.
Since the `flush_full` routine, regardless of storage targets would untrip
the PRELOAD switch, the snapshot target as expected untrips the switch. Now,
this means that a tree re-init is not run by BGSAVE or save on termsig.
As a consequence, while attempting to run bgsave/save on termsig, the new
keyspace directories are not found, resulting in flush failure. This commit
fixes it my simply checking if the target should untrip the switch or not.
Tests for the same were added
Sayan Nandan