并发地迭代映射并使用RLock/RUnlock进行映射写入。

huangapple
go评论111阅读模式
英文:

concurrent map iteration and map write with RLock/RUnlock

问题

不确定为什么我的程序会出现concurrent map iteration and map write错误。我在这里使用了RLock()/mv.RUnlock()：

  1. for k := range confirmed_slot {
  2.     keys = append(keys, k)
  3. }

这是我完整的Go程序用于测试：

  1. package main
  3. import (
  4. 	"container/list"
  5. 	"fmt"
  6. 	"math/rand"
  7. 	"sync"
  8. 	"time"
  9. 	"github.com/twotwotwo/sorts/sortutil"
  10. )
  12. var (
  13. 	queue          = list.New()
  14. 	confirmed_slot = map[uint64]string{}
  15. 	mv sync.RWMutex
  16. )
  18. func FetchConfirmedSlots() {
  19. 	ticker := time.NewTicker(1 * time.Second)
  20. 	for {
  21. 		mv.RLock()
  22. 		rand.Seed(time.Now().UnixNano())
  23. 		r := randSeq(10)
  24. 		slot := rand.Uint64()
  25. 		confirmed_slot[slot] = r
  26. 		queue.PushBack(slot)
  27. 		fmt.Println("Slot Added ", slot, "  ", len(confirmed_slot))
  28. 		mv.RUnlock()
  29. 		<-ticker.C
  30. 	}
  31. }
  33. func RemoveItemSlotFull() {
  34. 	ticker := time.NewTicker(1 * time.Millisecond)
  35. 	for {
  36. 		if queue.Len() == 150 {
  37. 			mv.RLock()
  38. 			front := queue.Front()
  39. 			queue.Remove(front)
  40. 			v, ok := front.Value.(uint64)
  41. 			if ok {
  42. 				fmt.Println("Slot deleted ", v)
  43. 				delete(confirmed_slot, v)
  44. 				fmt.Println("Slot deleted ", v, "  ", len(confirmed_slot))
  45. 			}
  46. 			mv.RUnlock()
  48. 		}
  49. 		<-ticker.C
  50. 	}
  51. }
  53. func GetLatestSlot() {
  54. 	ticker := time.NewTicker(1 * time.Second)
  55. 	for {
  56. 		mv.RLock()
  57. 		if queue.Len() > 0 {
  58. 			back := queue.Back()
  59. 			fmt.Println("Slot Fetched ", back.Value, " ", len(confirmed_slot))
  60. 		}
  61. 		mv.RUnlock()
  62. 		<-ticker.C
  63. 	}
  64. }
  66. func GetConfirmedBlockHashes() {
  67. 	ticker := time.NewTicker(1 * time.Second)
  68. 	for {
  69. 		if queue.Len() > 0 {
  70. 			mv.RLock()
  71. 			back := queue.Back()
  72. 			v, _ := back.Value.(uint64)
  73. 			keys := make([]uint64, 0, len(confirmed_slot))
  75. 			for k := range confirmed_slot {
  76. 				keys = append(keys, k)
  77. 			}
  79. 			n := sortutil.SearchUint64s(keys, v)
  80. 			fmt.Println("Found ... ", n, true)
  81. 			mv.RUnlock()
  83. 		}
  84. 		<-ticker.C
  85. 	}
  87. }
  89. func main() {
  91. 	go FetchConfirmedSlots()
  92. 	go RemoveItemSlotFull()
  93. 	go GetLatestSlot()
  95. 	go GetConfirmedBlockHashes()
  96. 	select {}
  98. }
  100. var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
  102. func randSeq(n int) string {
  103. 	b := make([]rune, n)
  104. 	for i := range b {
  105. 		b[i] = letters[rand.Intn(len(letters))]
  106. 	}
  107. 	return string(b)
  108. }
英文:

Not sure why my program is hitting the error of

concurrent map iteration and map write

I have put the RLock()/mv.RUnlock() here

  1. for k := range confirmed_slot {
  2. keys = append(keys, k)
  3. }

Here is my complete go program for test

  1. package main
  3. import (
  4. 	&quot;container/list&quot;
  5. 	&quot;fmt&quot;
  6. 	&quot;math/rand&quot;
  7. 	&quot;sync&quot;
  8. 	&quot;time&quot;
  9. 	&quot;github.com/twotwotwo/sorts/sortutil&quot;
  10. )
  12. var (
  13. 	queue          = list.New()
  14. 	confirmed_slot = map[uint64]string{}
  15. 	mv sync.RWMutex
  16. )
  18. func FetchConfirmedSlots() {
  19. 	ticker := time.NewTicker(1 * time.Second)
  20. 	for {
  21. 		mv.RLock()
  22. 		rand.Seed(time.Now().UnixNano())
  23. 		r := randSeq(10)
  24. 		slot := rand.Uint64()
  25. 		confirmed_slot[slot] = r
  26. 		queue.PushBack(slot)
  27. 		fmt.Println(&quot;Slot Added &quot; , slot , &quot;  &quot;, len(confirmed_slot))
  28. 		mv.RUnlock()
  29. 		&lt;-ticker.C
  30. 	}
  31. }
  33. func RemoveItemSlotFull() {
  34. 	ticker := time.NewTicker(1 * time.Millisecond)
  35. 	for {
  36. 		if queue.Len() == 150 {
  37. 			mv.RLock()
  38. 			front := queue.Front()
  39. 			queue.Remove(front)
  40. 			v, ok := front.Value.(uint64)
  41. 			if ok {
  42. 				fmt.Println(&quot;Slot deleted &quot; , v)
  43. 				delete(confirmed_slot, v)
  44. 				fmt.Println(&quot;Slot deleted &quot; , v , &quot;  &quot;, len(confirmed_slot))
  45. 			}
  46. 			mv.RUnlock()
  48. 		}
  49. 		&lt;-ticker.C
  50. 	}
  51. }
  53. func GetLatestSlot() {
  54. 	ticker := time.NewTicker(1 * time.Second)
  55. 	for {
  56. 		mv.RLock()
  57. 		if queue.Len() &gt;0  {
  58. 			back := queue.Back()
  59. 			fmt.Println(&quot;Slot Fetched &quot;, back.Value , &quot; &quot;,len(confirmed_slot))
  60. 		}
  61. 		mv.RUnlock()
  62. 		&lt;-ticker.C
  63. 	}
  64. }
  66. func GetConfirmedBlockHashes() {
  67. 	ticker := time.NewTicker(1 * time.Second)
  68. 	for {
  69. 		if queue.Len() &gt;0  {
  70. 			mv.RLock()
  71. 			back := queue.Back()
  72. 			v, _ := back.Value.(uint64)
  73. 			keys := make([]uint64, 0, len(confirmed_slot))
  76. 			for k := range confirmed_slot {
  77. 				keys = append(keys, k)
  78. 			}
  81. 			n := sortutil.SearchUint64s(keys,v)
  82. 			fmt.Println(&quot;Found ... &quot; , n, true)
  83. 			mv.RUnlock()
  85. 		}
  86. 		&lt;-ticker.C
  87. 	}
  89. }
  92. func main() {
  94. 	go FetchConfirmedSlots()
  95. 	go RemoveItemSlotFull()
  96. 	go GetLatestSlot()
  98. 	go GetConfirmedBlockHashes()
  99. 	select {}
  101. }
  103. var letters = []rune(&quot;abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ&quot;)
  105. func randSeq(n int) string {
  106. 	b := make([]rune, n)
  107. 	for i := range b {
  108. 		b[i] = letters[rand.Intn(len(letters))]
  109. 	}
  110. 	return string(b)
  111. }

答案1

得分: 2

请尝试使用mv.Lock()和mv.Unlock()代替mv.RLock()和mv.RUnlock()。您正在对confirmed_slot进行写操作。

RLock()和RUnlock()用于读取操作-它们允许多个线程同时读取，只要没有线程在写入。

Lock()和Unlock()将确保只有一个线程同时持有锁，无论是读取还是写入。

英文:

Instead of mv.RLock() and mv.RUnlock() try mv.Lock() and mv.Unlock(). You are writing to the confirmed_slot.

Rlock() and RUnlock() are for reads - they allow many threads to read at once, as long as none are writing.

Lock() and Unlock() will ensure that only one thread holds the lock at a time, regardless of wheather it is reading or writing.

huangapple
  • 本文由 发表于 2022年3月5日 00:25:08
  • 转载请务必保留本文链接：https://go.coder-hub.com/71354301.html
  • go
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定