About pre-apply in JournalSystem

[QueenOfBees]

Alluxio Version: release-310

Describe the bug

Let's say we have a x = 3 in memory

write request: try (JournalContext c = journal.createJournalContext()) { x = 3 c.append(exampleBlockJournalEntry); }

read request: return x

if the leader node lost leadership while flushing pending jounal (network reason/long time gc), the read request will see x = 3 immediately, that means we read a uncommited change, is this correct?

I'd appreciate it if you could give me a hint.

To Reproduce

Expected behavior

Urgency

Are you planning to fix it

Additional context

[QueenOfBees]

my another conflusion is: what's the benefit of pre-apply exactly. "avoid journaling operations which do not result in state modification" (comment of RaftJounalSystem)，which is difficult to understand

[YichuanSun]

Actually now we have no leading node in Alluxio 3.x, Alluxio 3.x is a decentralized architecture.