About the consistency of kvstore in raftexample when restarting

[chenyang8094]

Assuming that kvstore has multiple snapshots and multiple wals on disk, when kvstore restarts, it will first execute replayWAL, which will load the snapshot and replay the wal corresponding to the raft instance. Then the latest snapshot (that is, the latest snapshot file in time) will be loaded in newKVStore.

My question is, how can the snapshot loaded in replayWAL be the same as the snapshot loaded by newKVStore? If not, how to ensure that the records in raft are consistent with the data in kvstore?

Because when we create a snapshot, we first create a snapshot and then write wal, so it is possible that the latest snapshot is not recorded by wal.

[chenyang8094]

I found that how to recovery data in newKVStore has undergone many modifications. Maybe the current implementation does not make a consistency guarantee? see PR： #11889

There are still these PRs discussing this issue before： #9262 #9263

[chenyang8094]

I make a PR #16438 to fix that.