tikv: cleanup outdate regions's memory from region-cache in 2.1 (#11931)

go.mod

@@ -24,7 +24,7 @@ require (
 	github.com/golang/groupcache v0.0.0-20181024230925-c65c006176ff // indirect
 	github.com/golang/protobuf v1.1.0
 	github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db // indirect
-	github.com/google/btree v0.0.0-20161217183710-316fb6d3f031
+	github.com/google/btree v1.0.0
 	github.com/google/uuid v1.1.1
 	github.com/gorilla/context v0.0.0-20160226214623-1ea25387ff6f // indirect
 	github.com/gorilla/mux v0.0.0-20170228224354-599cba5e7b61

go.sum

@@ -49,8 +49,8 @@ github.com/golang/protobuf v1.1.0 h1:0iH4Ffd/meGoXqF2lSAhZHt8X+cPgkfn/cb6Cce5Vpc
 github.com/golang/protobuf v1.1.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db h1:woRePGFeVFfLKN/pOkfl+p/TAqKOfFu+7KPlMVpok/w=
 github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
-github.com/google/btree v0.0.0-20161217183710-316fb6d3f031 h1:yAx4v8FikdsGCBPzIaT2F+0WH0J+wcL7cQD9n3UbyOk=
-github.com/google/btree v0.0.0-20161217183710-316fb6d3f031/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
+github.com/google/btree v1.0.0 h1:0udJVsspx3VBr5FwtLhQQtuAsVc79tTq0ocGIPAU6qo=
+github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/shlex v0.0.0-20181106134648-c34317bd91bf/go.mod h1:RpwtwJQFrIEPstU94h88MWPXP2ektJZ8cZ0YntAmXiE=
 github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=

store/tikv/region_cache.go

@@ -546,7 +546,7 @@ func (c *RegionCache) DropStoreOnSendRequestFail(ctx *RPCContext, err error) {
 		return
 	}
 	for id, r := range c.mu.regions {
-		if r.region.peer.GetStoreId() == failedStoreID {
+		if !r.isValid() || r.region.peer.GetStoreId() == failedStoreID {
 			c.dropRegionFromCache(id)
 		}
 	}