try replica read if leader is exhausted

Signed-off-by: rishabh_mittal <[email protected]>
tikv · Dec 20, 2024 · e7babf8 · e7babf8
1 parent ee1cfd2
commit e7babf8
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Showing 3 changed files with 16 additions and 15 deletions.
diff --git a/internal/locate/region_request_state_test.go b/internal/locate/region_request_state_test.go
@@ -324,7 +324,7 @@ func TestRegionCacheStaleRead(t *testing.T) {
 			leaderRegionValid:       true,
 			leaderAsyncReload:       util.Some(true),
 			leaderSuccessReplica:    []string{"z2", "z3"},
-			leaderSuccessReadType:   SuccessStaleRead,
+			leaderSuccessReadType:   SuccessFollowerRead,
 			followerRegionValid:     true,
 			followerAsyncReload:     util.Some(false),
 			followerSuccessReplica:  []string{"z2"},
@@ -346,7 +346,7 @@ func TestRegionCacheStaleRead(t *testing.T) {
 			leaderRegionValid:       true,
 			leaderAsyncReload:       util.Some(true),
 			leaderSuccessReplica:    []string{"z2", "z3"},
-			leaderSuccessReadType:   SuccessStaleRead,
+			leaderSuccessReadType:   SuccessFollowerRead,
 			followerRegionValid:     true,
 			followerAsyncReload:     util.None[bool](),
 			followerSuccessReplica:  []string{"z2"},
@@ -434,11 +434,11 @@ func TestRegionCacheStaleRead(t *testing.T) {
 			leaderRegionValid:       true,
 			leaderAsyncReload:       util.Some(true),
 			leaderSuccessReplica:    []string{"z2", "z3"},
-			leaderSuccessReadType:   SuccessStaleRead,
+			leaderSuccessReadType:   SuccessFollowerRead,
 			followerRegionValid:     true,
 			followerAsyncReload:     util.Some(true),
 			followerSuccessReplica:  []string{"z2", "z3"},
-			followerSuccessReadType: SuccessStaleRead,
+			followerSuccessReadType: SuccessFollowerRead,
 		},
 		{
 			do:                      leaderDown,
@@ -447,11 +447,11 @@ func TestRegionCacheStaleRead(t *testing.T) {
 			leaderRegionValid:       true,
 			leaderAsyncReload:       util.Some(true),
 			leaderSuccessReplica:    []string{"z3"},
-			leaderSuccessReadType:   SuccessStaleRead,
+			leaderSuccessReadType:   SuccessFollowerRead,
 			followerRegionValid:     true,
 			followerAsyncReload:     util.Some(true),
 			followerSuccessReplica:  []string{"z3"},
-			followerSuccessReadType: SuccessStaleRead,
+			followerSuccessReadType: SuccessFollowerRead,
 		},
 		{
 			do:                      leaderDown,
@@ -460,11 +460,11 @@ func TestRegionCacheStaleRead(t *testing.T) {
 			leaderRegionValid:       true,
 			leaderAsyncReload:       util.Some(true),
 			leaderSuccessReplica:    []string{"z3"},
-			leaderSuccessReadType:   SuccessStaleRead,
+			leaderSuccessReadType:   SuccessFollowerRead,
 			followerRegionValid:     true,
 			followerAsyncReload:     util.Some(true),
 			followerSuccessReplica:  []string{"z3"},
-			followerSuccessReadType: SuccessStaleRead,
+			followerSuccessReadType: SuccessFollowerRead,
 		},
 	}
 	tests := []func(*testRegionCacheStaleReadSuite, *RegionCacheTestCase){
@@ -556,6 +556,8 @@ func testStaleRead(s *testRegionCacheStaleReadSuite, r *RegionCacheTestCase, zon
 	_, successZone, successReadType := s.extractResp(resp)
 	find := false
 	if leaderZone {
+		funcName := runtime.FuncForPC(reflect.ValueOf(r.do).Pointer()).Name()
+		fmt.Printf("Function name of r.do(): %s\n", funcName)
 		s.Equal(r.leaderSuccessReadType, successReadType, msg)
 		for _, z := range r.leaderSuccessReplica {
 			if z == successZone {

diff --git a/internal/locate/replica_selector.go b/internal/locate/replica_selector.go
@@ -307,11 +307,10 @@ func (s *ReplicaSelectMixedStrategy) next(selector *replicaSelector) *replica {
 func (s *ReplicaSelectMixedStrategy) canSendReplicaRead(selector *replicaSelector) bool {
 	replicas := selector.replicas
 	replica := replicas[s.leaderIdx]
-	liveness := replica.store.getLivenessState()
-	epochStale := replica.isEpochStale()
 
-	if liveness != reachable || epochStale || replica.hasFlag(deadlineErrUsingConfTimeoutFlag) || replica.hasFlag(serverIsBusyFlag) {
-		// don't overwhelm the leader is busy, timeout, not accessible or stale epoch.
+	maxAttempt := 1
+	if !replica.isExhausted(maxAttempt, 0) || replica.hasFlag(deadlineErrUsingConfTimeoutFlag) || replica.hasFlag(serverIsBusyFlag) {
+		// don't do the replica read if leader is not exhausted or leader has timeout or server busy error.
 		return false
 	}
 	return true

diff --git a/internal/locate/replica_selector_test.go b/internal/locate/replica_selector_test.go
@@ -898,8 +898,8 @@ func TestReplicaReadAccessPathByCase2(t *testing.T) {
 		expect: &accessPathResult{
 			accessPath: []string{
 				"{addr: store1, replica-read: false, stale-read: true}",
-				"{addr: store2, replica-read: false, stale-read: true}",
-				"{addr: store3, replica-read: false, stale-read: true}"},
+				"{addr: store2, replica-read: true, stale-read: false}",
+				"{addr: store3, replica-read: true, stale-read: false}"},
 			respErr:         "",
 			respRegionError: fakeEpochNotMatch,
 			backoffCnt:      3,
@@ -2125,7 +2125,7 @@ func TestReplicaReadAccessPathByStaleReadCase(t *testing.T) {
 				accessPath: []string{
 					"{addr: store2, replica-read: false, stale-read: true}",
 					"{addr: store1, replica-read: false, stale-read: false}",
-					"{addr: store3, replica-read: false, stale-read: true}",
+					"{addr: store3, replica-read: true, stale-read: false}",
 				},
 				respErr:         "",
 				respRegionError: nil,