/
resolvedts_heap.go
141 lines (123 loc) · 3.5 KB
/
resolvedts_heap.go
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// Copyright 2021 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 kv
import (
"container/heap"
"time"
)
type tsItem struct {
sortByEvTime bool
resolvedTs uint64
eventTime time.Time
penalty int
}
func newResolvedTsItem(ts uint64) tsItem {
return tsItem{resolvedTs: ts, eventTime: time.Now()}
}
func newEventTimeItem() tsItem {
return tsItem{sortByEvTime: true, eventTime: time.Now()}
}
// regionTsInfo contains region resolvedTs information
type regionTsInfo struct {
regionID uint64
index int
ts tsItem
}
type regionTsHeap []*regionTsInfo
func (rh regionTsHeap) Len() int { return len(rh) }
func (rh regionTsHeap) Less(i, j int) bool {
if rh[i].ts.sortByEvTime {
return rh[i].ts.eventTime.Before(rh[j].ts.eventTime)
}
return rh[i].ts.resolvedTs < rh[j].ts.resolvedTs
}
func (rh regionTsHeap) Swap(i, j int) {
rh[i], rh[j] = rh[j], rh[i]
rh[i].index = i
rh[j].index = j
}
func (rh *regionTsHeap) Push(x interface{}) {
n := len(*rh)
item := x.(*regionTsInfo)
item.index = n
*rh = append(*rh, item)
}
func (rh *regionTsHeap) Pop() interface{} {
old := *rh
n := len(old)
item := old[n-1]
item.index = -1 // for safety
*rh = old[0 : n-1]
return item
}
// regionTsManager is a used to maintain resolved ts information for N regions.
// This struct is not thread safe
type regionTsManager struct {
// mapping from regionID to regionTsInfo object
m map[uint64]*regionTsInfo
h regionTsHeap
}
func newRegionTsManager() *regionTsManager {
return ®ionTsManager{
m: make(map[uint64]*regionTsInfo),
h: make(regionTsHeap, 0),
}
}
// Upsert implements insert and update on duplicated key
func (rm *regionTsManager) Upsert(item *regionTsInfo) {
if old, ok := rm.m[item.regionID]; ok {
// in a single resolved ts manager, we should not expect a fallback resolved event
// but it's ok that we use fallback resolved event to increase penalty
if !item.ts.sortByEvTime {
if item.ts.resolvedTs <= old.ts.resolvedTs && item.ts.eventTime.After(old.ts.eventTime) {
old.ts.penalty++
old.ts.eventTime = item.ts.eventTime
heap.Fix(&rm.h, old.index)
} else if item.ts.resolvedTs > old.ts.resolvedTs {
old.ts.resolvedTs = item.ts.resolvedTs
old.ts.eventTime = item.ts.eventTime
old.ts.penalty = 0
heap.Fix(&rm.h, old.index)
}
} else {
if item.ts.eventTime.After(old.ts.eventTime) {
old.ts.eventTime = item.ts.eventTime
heap.Fix(&rm.h, old.index)
}
}
} else {
heap.Push(&rm.h, item)
rm.m[item.regionID] = item
}
}
// Pop pops a regionTsInfo from rts heap, delete it from region rts map
func (rm *regionTsManager) Pop() *regionTsInfo {
if rm.Len() == 0 {
return nil
}
item := heap.Pop(&rm.h).(*regionTsInfo)
delete(rm.m, item.regionID)
return item
}
// Remove removes item from regionTsManager
func (rm *regionTsManager) Remove(regionID uint64) *regionTsInfo {
if item, ok := rm.m[regionID]; ok {
delete(rm.m, item.regionID)
return heap.Remove(&rm.h, item.index).(*regionTsInfo)
}
return nil
}
// Len returns the item count in regionTsManager
func (rm *regionTsManager) Len() int {
return len(rm.m)
}