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raft: move progress to progress.go

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This commit is contained in:
Xiang Li 2015-03-19 10:04:48 -07:00
parent a475e90c9c
commit 2adb58f9de
2 changed files with 151 additions and 132 deletions
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151
raft/progress.go Normal file
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@ -0,0 +1,151 @@
// Copyright 2015 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package raft
import "fmt"
const (
ProgressStateProbe ProgressStateType = iota
ProgressStateReplicate
ProgressStateSnapshot
)
type ProgressStateType uint64
var prstmap = [...]string{
"ProgressStateProbe",
"ProgressStateReplicate",
"ProgressStateSnapshot",
}
func (st ProgressStateType) String() string { return prstmap[uint64(st)] }
// Progress represents a follower’s progress in the view of the leader. Leader maintains
// progresses of all followers, and sends entries to the follower based on its progress.
type Progress struct {
Match, Next uint64
// When in ProgressStateProbe, leader sends at most one replication message
// per heartbeat interval. It also probes actual progress of the follower.
//
// When in ProgressStateReplicate, leader optimistically increases next
// to the latest entry sent after sending replication message. This is
// an optimized state for fast replicating log entries to the follower.
//
// When in ProgressStateSnapshot, leader should have sent out snapshot
// before and stops sending any replication message.
State ProgressStateType
// Paused is used in ProgressStateProbe.
// When Paused is true, raft should pause sending replication message to this peer.
Paused bool
// PendingSnapshot is used in ProgressStateSnapshot.
// If there is a pending snapshot, the pendingSnapshot will be set to the
// index of the snapshot. If pendingSnapshot is set, the replication process of
// this Progress will be paused. raft will not resend snapshot until the pending one
// is reported to be failed.
PendingSnapshot uint64
}
func (pr *Progress) resetState(state ProgressStateType) {
pr.Paused = false
pr.PendingSnapshot = 0
pr.State = state
}
func (pr *Progress) becomeProbe() {
// If the original state is ProgressStateSnapshot, progress knows that
// the pending snapshot has been sent to this peer successfully, then
// probes from pendingSnapshot + 1.
if pr.State == ProgressStateSnapshot {
pendingSnapshot := pr.PendingSnapshot
pr.resetState(ProgressStateProbe)
pr.Next = max(pr.Match+1, pendingSnapshot+1)
} else {
pr.resetState(ProgressStateProbe)
pr.Next = pr.Match + 1
}
}
func (pr *Progress) becomeReplicate() {
pr.resetState(ProgressStateReplicate)
pr.Next = pr.Match + 1
}
func (pr *Progress) becomeSnapshot(snapshoti uint64) {
pr.resetState(ProgressStateSnapshot)
pr.PendingSnapshot = snapshoti
}
// maybeUpdate returns false if the given n index comes from an outdated message.
// Otherwise it updates the progress and returns true.
func (pr *Progress) maybeUpdate(n uint64) bool {
var updated bool
if pr.Match < n {
pr.Match = n
updated = true
pr.resume()
}
if pr.Next < n+1 {
pr.Next = n + 1
}
return updated
}
func (pr *Progress) optimisticUpdate(n uint64) { pr.Next = n + 1 }
// maybeDecrTo returns false if the given to index comes from an out of order message.
// Otherwise it decreases the progress next index to min(rejected, last) and returns true.
func (pr *Progress) maybeDecrTo(rejected, last uint64) bool {
if pr.State == ProgressStateReplicate {
// the rejection must be stale if the progress has matched and "rejected"
// is smaller than "match".
if rejected <= pr.Match {
return false
}
// directly decrease next to match + 1
pr.Next = pr.Match + 1
return true
}
// the rejection must be stale if "rejected" does not match next - 1
if pr.Next-1 != rejected {
return false
}
if pr.Next = min(rejected, last+1); pr.Next < 1 {
pr.Next = 1
}
pr.resume()
return true
}
func (pr *Progress) pause() { pr.Paused = true }
func (pr *Progress) resume() { pr.Paused = false }
// isPaused returns whether progress stops sending message.
func (pr *Progress) isPaused() bool {
return pr.State == ProgressStateProbe && pr.Paused || pr.State == ProgressStateSnapshot
}
func (pr *Progress) snapshotFailure() { pr.PendingSnapshot = 0 }
// maybeSnapshotAbort unsets pendingSnapshot if Match is equal or higher than
// the pendingSnapshot
func (pr *Progress) maybeSnapshotAbort() bool {
return pr.State == ProgressStateSnapshot && pr.Match >= pr.PendingSnapshot
}
func (pr *Progress) String() string {
return fmt.Sprintf("next = %d, match = %d, state = %s, waiting = %v, pendingSnapshot = %d", pr.Next, pr.Match, pr.State, pr.isPaused(), pr.PendingSnapshot)
}

132
raft/raft.go
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@ -51,138 +51,6 @@ func (st StateType) String() string {
return stmap[uint64(st)] return stmap[uint64(st)]
} }
const (
ProgressStateProbe ProgressStateType = iota
ProgressStateReplicate
ProgressStateSnapshot
)
type ProgressStateType uint64
var prstmap = [...]string{
"ProgressStateProbe",
"ProgressStateReplicate",
"ProgressStateSnapshot",
}
func (st ProgressStateType) String() string { return prstmap[uint64(st)] }
type Progress struct {
Match, Next uint64
// When in ProgressStateProbe, leader sends at most one replication message
// per heartbeat interval. It also probes actual progress of the follower.
//
// When in ProgressStateReplicate, leader optimistically increases next
// to the latest entry sent after sending replication message. This is
// an optimized state for fast replicating log entries to the follower.
//
// When in ProgressStateSnapshot, leader should have sent out snapshot
// before and stops sending any replication message.
State ProgressStateType
// Paused is used in ProgressStateProbe.
// When Paused is true, raft should pause sending replication message to this peer.
Paused bool
// PendingSnapshot is used in ProgressStateSnapshot.
// If there is a pending snapshot, the pendingSnapshot will be set to the
// index of the snapshot. If pendingSnapshot is set, the replication process of
// this Progress will be paused. raft will not resend snapshot until the pending one
// is reported to be failed.
PendingSnapshot uint64
}
func (pr *Progress) resetState(state ProgressStateType) {
pr.Paused = false
pr.PendingSnapshot = 0
pr.State = state
}
func (pr *Progress) becomeProbe() {
// If the original state is ProgressStateSnapshot, progress knows that
// the pending snapshot has been sent to this peer successfully, then
// probes from pendingSnapshot + 1.
if pr.State == ProgressStateSnapshot {
pendingSnapshot := pr.PendingSnapshot
pr.resetState(ProgressStateProbe)
pr.Next = max(pr.Match+1, pendingSnapshot+1)
} else {
pr.resetState(ProgressStateProbe)
pr.Next = pr.Match + 1
}
}
func (pr *Progress) becomeReplicate() {
pr.resetState(ProgressStateReplicate)
pr.Next = pr.Match + 1
}
func (pr *Progress) becomeSnapshot(snapshoti uint64) {
pr.resetState(ProgressStateSnapshot)
pr.PendingSnapshot = snapshoti
}
// maybeUpdate returns false if the given n index comes from an outdated message.
// Otherwise it updates the progress and returns true.
func (pr *Progress) maybeUpdate(n uint64) bool {
var updated bool
if pr.Match < n {
pr.Match = n
updated = true
pr.resume()
}
if pr.Next < n+1 {
pr.Next = n + 1
}
return updated
}
func (pr *Progress) optimisticUpdate(n uint64) { pr.Next = n + 1 }
// maybeDecrTo returns false if the given to index comes from an out of order message.
// Otherwise it decreases the progress next index to min(rejected, last) and returns true.
func (pr *Progress) maybeDecrTo(rejected, last uint64) bool {
if pr.State == ProgressStateReplicate {
// the rejection must be stale if the progress has matched and "rejected"
// is smaller than "match".
if rejected <= pr.Match {
return false
}
// directly decrease next to match + 1
pr.Next = pr.Match + 1
return true
}
// the rejection must be stale if "rejected" does not match next - 1
if pr.Next-1 != rejected {
return false
}
if pr.Next = min(rejected, last+1); pr.Next < 1 {
pr.Next = 1
}
pr.resume()
return true
}
func (pr *Progress) pause() { pr.Paused = true }
func (pr *Progress) resume() { pr.Paused = false }
// isPaused returns whether progress stops sending message.
func (pr *Progress) isPaused() bool {
return pr.State == ProgressStateProbe && pr.Paused || pr.State == ProgressStateSnapshot
}
func (pr *Progress) snapshotFailure() { pr.PendingSnapshot = 0 }
// maybeSnapshotAbort unsets pendingSnapshot if Match is equal or higher than
// the pendingSnapshot
func (pr *Progress) maybeSnapshotAbort() bool {
return pr.State == ProgressStateSnapshot && pr.Match >= pr.PendingSnapshot
}
func (pr *Progress) String() string {
return fmt.Sprintf("next = %d, match = %d, state = %s, waiting = %v, pendingSnapshot = %d", pr.Next, pr.Match, pr.State, pr.isPaused(), pr.PendingSnapshot)
}
type raft struct { type raft struct {
pb.HardState pb.HardState