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Abhilash S.L3b494632019-07-16 15:51:09 +05301// Copyright 2019 The etcd Authors
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
15package tracker
17// StateType is the state of a tracked follower.
18type StateType uint64
20const (
21 // StateProbe indicates a follower whose last index isn't known. Such a
22 // follower is "probed" (i.e. an append sent periodically) to narrow down
23 // its last index. In the ideal (and common) case, only one round of probing
24 // is necessary as the follower will react with a hint. Followers that are
25 // probed over extended periods of time are often offline.
26 StateProbe StateType = iota
27 // StateReplicate is the state steady in which a follower eagerly receives
28 // log entries to append to its log.
29 StateReplicate
30 // StateSnapshot indicates a follower that needs log entries not available
31 // from the leader's Raft log. Such a follower needs a full snapshot to
32 // return to StateReplicate.
33 StateSnapshot
36var prstmap = [...]string{
37 "StateProbe",
38 "StateReplicate",
39 "StateSnapshot",
42func (st StateType) String() string { return prstmap[uint64(st)] }