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FOLLOWERINFO(11)

acceptedEpoch

LearnerInfo

FOLLOWERINFO(acceptedEpoch)

The follower has accepted epoch acceptedEpoch.

DIFF(13)

last committed zxid

n/a

DIFF(lastCommittedZxid)

lastCommittedZxid is the last zxid committed by the leader.

TRUNC(14)

truncZxid

n/a

TRUNC(truncZxid)

Truncate the history to truncZxid

SNAP(15)

n/a lastZxid

n/a

SNAP

A state transfer (aka snapshot) will be sent to the follower. this will be a fuzzy state transfer that may include zxids being sent to the follower. The state transfer will immediately follow this packet.

OBSERVERINFO(16)

last zxid learned

LearnerInfo

OBSERVERINFO(lastZxid)

The observer has accepted up to lastZxid.

LEADERINFO(17)

proposed epoch

protocol

LEADERINFO(e)

The new proposed epoch

ACKEPOCH(18)

lastZxid

currentEpoch

ACKEPOCH(lastZxid, currentEpoch)

Acknowledge the acceptance of the new epoch. If the follower has already acknowledged the given epoch, it passes -1 as the currentEpoch to signal that the new epoch is not acknowledged. (We still need to send lastZxid for syncing if necessary)

NEWLEADER(10)

e << 32

n/a

NEWLEADER(e)

Accept this leader as the leader of the epoch e.

UPTODATE(12)

n/a

n/a

UPTODATE

The follower is now uptodate enough to begin serving clients.

PROPOSAL(2)

zxid of proposal

proposed message

PROPOSAL(zxid, data)

Propose a message. (Request that it be accepted into a followers history.)

ACK(3)

zxid of proposal to ack

n/a

ACK(zxid)

Everything sent to the follower by the leader up to zxid has been accepted into its history (logged to disk).

COMMIT(4)

zxid of proposal to commit

n/a

COMMIT(zxid)

Everything in the followers history up to zxid should be committed (aka delivered).

INFORM(8)

zxid of proposal

data of proposal

INFORM(zxid, data)

Deliver the data. (Only used with observers.)