forked from tikv/pd
-
Notifications
You must be signed in to change notification settings - Fork 0
/
region_scatterer.go
245 lines (218 loc) · 7.11 KB
/
region_scatterer.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
// Copyright 2017 PingCAP, 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package schedule
import (
"math/rand"
"sync"
"github.com/pingcap/kvproto/pkg/metapb"
"github.com/pingcap/pd/server/core"
"github.com/pingcap/pd/server/namespace"
"github.com/pkg/errors"
)
type selectedStores struct {
mu sync.Mutex
stores map[uint64]struct{}
}
func newSelectedStores() *selectedStores {
return &selectedStores{
stores: make(map[uint64]struct{}),
}
}
func (s *selectedStores) put(id uint64) bool {
s.mu.Lock()
defer s.mu.Unlock()
if _, ok := s.stores[id]; ok {
return false
}
s.stores[id] = struct{}{}
return true
}
func (s *selectedStores) reset() {
s.mu.Lock()
defer s.mu.Unlock()
s.stores = make(map[uint64]struct{})
}
func (s *selectedStores) newFilter() Filter {
s.mu.Lock()
defer s.mu.Unlock()
cloned := make(map[uint64]struct{})
for id := range s.stores {
cloned[id] = struct{}{}
}
return NewExcludedFilter(nil, cloned)
}
// RegionScatterer scatters regions.
type RegionScatterer struct {
cluster Cluster
classifier namespace.Classifier
filters []Filter
selected *selectedStores
}
// NewRegionScatterer creates a region scatterer.
func NewRegionScatterer(cluster Cluster, classifier namespace.Classifier) *RegionScatterer {
return &RegionScatterer{
cluster: cluster,
classifier: classifier,
filters: []Filter{StoreStateFilter{}},
selected: newSelectedStores(),
}
}
// Scatter relocates the region.
func (r *RegionScatterer) Scatter(region *core.RegionInfo) (*Operator, error) {
if r.cluster.IsRegionHot(region.GetID()) {
return nil, errors.Errorf("region %d is a hot region", region.GetID())
}
if len(region.GetPeers()) != r.cluster.GetMaxReplicas() {
return nil, errors.Errorf("the number replicas of region %d is not expected", region.GetID())
}
if region.GetLeader() == nil {
return nil, errors.Errorf("region %d has no leader", region.GetID())
}
return r.scatterRegion(region), nil
}
func (r *RegionScatterer) scatterRegion(region *core.RegionInfo) *Operator {
stores := r.collectAvailableStores(region)
var (
targetPeers []*metapb.Peer
replacedPeers []*metapb.Peer
)
for _, peer := range region.GetPeers() {
if len(stores) == 0 {
// Reset selected stores if we have no available stores.
r.selected.reset()
stores = r.collectAvailableStores(region)
}
if r.selected.put(peer.GetStoreId()) {
delete(stores, peer.GetStoreId())
targetPeers = append(targetPeers, peer)
replacedPeers = append(replacedPeers, peer)
continue
}
newPeer := r.selectPeerToReplace(stores, region, peer)
if newPeer == nil {
targetPeers = append(targetPeers, peer)
replacedPeers = append(replacedPeers, peer)
continue
}
// Remove it from stores and mark it as selected.
delete(stores, newPeer.GetStoreId())
r.selected.put(newPeer.GetStoreId())
targetPeers = append(targetPeers, newPeer)
replacedPeers = append(replacedPeers, peer)
}
return r.createOperator(region, replacedPeers, targetPeers)
}
func (r *RegionScatterer) createOperator(origin *core.RegionInfo, replacedPeers, targetPeers []*metapb.Peer) *Operator {
// Randomly pick a leader
i := rand.Intn(len(targetPeers))
targetLeaderPeer := targetPeers[i]
originLeaderStoreID := origin.GetLeader().GetStoreId()
originStoreIDs := origin.GetStoreIds()
steps := make([]OperatorStep, 0, len(targetPeers)*3+1)
// deferSteps will append to the end of the steps
deferSteps := make([]OperatorStep, 0, 5)
var kind OperatorKind
sameLeader := targetLeaderPeer.GetStoreId() == originLeaderStoreID
// No need to do anything
if sameLeader {
isSame := true
for _, peer := range targetPeers {
if _, ok := originStoreIDs[peer.GetStoreId()]; !ok {
isSame = false
break
}
}
if isSame {
return nil
}
}
// Creates the first step
if _, ok := originStoreIDs[targetLeaderPeer.GetStoreId()]; !ok {
st := CreateAddPeerSteps(targetLeaderPeer.GetStoreId(), targetLeaderPeer.GetId(), r.cluster)
steps = append(steps, st...)
// Do not transfer leader to the newly added peer
// Ref: https://github.com/tikv/tikv/issues/3819
deferSteps = append(deferSteps, TransferLeader{FromStore: originLeaderStoreID, ToStore: targetLeaderPeer.GetStoreId()})
deferSteps = append(deferSteps, RemovePeer{FromStore: replacedPeers[i].GetStoreId()})
kind |= OpLeader
kind |= OpRegion
} else {
if !sameLeader {
steps = append(steps, TransferLeader{FromStore: originLeaderStoreID, ToStore: targetLeaderPeer.GetStoreId()})
kind |= OpLeader
}
}
// For the other steps
for j, peer := range targetPeers {
if peer.GetId() == targetLeaderPeer.GetId() {
continue
}
if _, ok := originStoreIDs[peer.GetStoreId()]; ok {
continue
}
if replacedPeers[j].GetStoreId() == originLeaderStoreID {
st := CreateAddPeerSteps(peer.GetStoreId(), peer.GetId(), r.cluster)
st = append(st, RemovePeer{FromStore: replacedPeers[j].GetStoreId()})
deferSteps = append(deferSteps, st...)
kind |= OpRegion | OpLeader
continue
}
st := CreateAddPeerSteps(peer.GetStoreId(), peer.GetId(), r.cluster)
steps = append(steps, st...)
steps = append(steps, RemovePeer{FromStore: replacedPeers[j].GetStoreId()})
kind |= OpRegion
}
steps = append(steps, deferSteps...)
op := NewOperator("scatter-region", origin.GetID(), origin.GetRegionEpoch(), kind, steps...)
op.SetPriorityLevel(core.HighPriority)
return op
}
func (r *RegionScatterer) selectPeerToReplace(stores map[uint64]*core.StoreInfo, region *core.RegionInfo, oldPeer *metapb.Peer) *metapb.Peer {
// scoreGuard guarantees that the distinct score will not decrease.
regionStores := r.cluster.GetRegionStores(region)
sourceStore := r.cluster.GetStore(oldPeer.GetStoreId())
scoreGuard := NewDistinctScoreFilter(r.cluster.GetLocationLabels(), regionStores, sourceStore)
candidates := make([]*core.StoreInfo, 0, len(stores))
for _, store := range stores {
if scoreGuard.FilterTarget(r.cluster, store) {
continue
}
candidates = append(candidates, store)
}
if len(candidates) == 0 {
return nil
}
target := candidates[rand.Intn(len(candidates))]
newPeer, err := r.cluster.AllocPeer(target.GetId())
if err != nil {
return nil
}
return newPeer
}
func (r *RegionScatterer) collectAvailableStores(region *core.RegionInfo) map[uint64]*core.StoreInfo {
namespace := r.classifier.GetRegionNamespace(region)
filters := []Filter{
r.selected.newFilter(),
NewExcludedFilter(nil, region.GetStoreIds()),
NewNamespaceFilter(r.classifier, namespace),
}
filters = append(filters, r.filters...)
stores := r.cluster.GetStores()
targets := make(map[uint64]*core.StoreInfo, len(stores))
for _, store := range stores {
if !FilterTarget(r.cluster, store, filters) && !store.Stats.GetIsBusy() {
targets[store.GetId()] = store
}
}
return targets
}