[GitHub] [servicecomb-service-center] DFSOrange commented on a change in pull request #1070: cache use concurrentmap

[GitBox <gi...@apache.org>]

DFSOrange commented on a change in pull request #1070:
URL: https://github.com/apache/servicecomb-service-center/pull/1070#discussion_r658425986



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File path: datasource/mongo/sd/dep_cache.go
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@@ -23,25 +23,31 @@ import (
 
 	"github.com/apache/servicecomb-service-center/datasource/mongo/client/model"
 	"github.com/apache/servicecomb-service-center/datasource/sdcommon"
+	cmap "github.com/orcaman/concurrent-map"
 	"go.mongodb.org/mongo-driver/bson"
 )
 
 type depStore struct {
-	dirty      bool
-	d          *DocStore
-	indexCache *IndexCache
+	dirty bool
+	// the key is documentID, is value is mongo document.
+	concurrentMap cmap.ConcurrentMap

Review comment:
       > 为何不用sync.Map
   
   主要有两个原因:
   1. [官方文档](https://golang.org/pkg/sync/#Map)介绍sync.map主要适用于两个场景1.key写入一次而读多次2.多个goroutine读写不相交的键值对，在实例服务变化频繁场景下不满足以上两个约束
   2. concurrentmap使用分片hash，sync.mapz是两层map（read+dirty），理论性能前者更好




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