br: enable follower handler again

br/pkg/restore/split/client.go

@@ -87,7 +87,7 @@ type SplitClient interface {
 	GetOperator(ctx context.Context, regionID uint64) (*pdpb.GetOperatorResponse, error)
 	// ScanRegions gets a list of regions, starts from the region that contains key.
 	// Limit limits the maximum number of regions returned.
-	ScanRegions(ctx context.Context, key, endKey []byte, limit int) ([]*RegionInfo, error)
+	ScanRegions(ctx context.Context, key, endKey []byte, limit int, opts ...opt.GetRegionOption) ([]*RegionInfo, error)
 	// GetPlacementRule loads a placement rule from PD.
 	GetPlacementRule(ctx context.Context, groupID, ruleID string) (*pdhttp.Rule, error)
 	// SetPlacementRule insert or update a placement rule to PD.
@@ -741,14 +741,14 @@ func (c *pdClient) GetOperator(ctx context.Context, regionID uint64) (*pdpb.GetO
 	return c.client.GetOperator(ctx, regionID)
 }
 
-func (c *pdClient) ScanRegions(ctx context.Context, key, endKey []byte, limit int) ([]*RegionInfo, error) {
+func (c *pdClient) ScanRegions(ctx context.Context, key, endKey []byte, limit int, opts ...opt.GetRegionOption) ([]*RegionInfo, error) {
 	failpoint.Inject("no-leader-error", func(_ failpoint.Value) {
 		logutil.CL(ctx).Debug("failpoint no-leader-error injected.")
 		failpoint.Return(nil, status.Error(codes.Unavailable, "not leader"))
 	})
 
 	//nolint:staticcheck
-	regions, err := c.client.ScanRegions(ctx, key, endKey, limit, opt.WithAllowFollowerHandle())
+	regions, err := c.client.ScanRegions(ctx, key, endKey, limit, opts...)
 	if err != nil {
 		return nil, errors.Trace(err)
 	}

br/pkg/restore/split/mock_pd_client.go

@@ -146,7 +146,7 @@ func (c *TestClient) GetOperator(context.Context, uint64) (*pdpb.GetOperatorResp
 	}, nil
 }
 
-func (c *TestClient) ScanRegions(ctx context.Context, key, endKey []byte, limit int) ([]*RegionInfo, error) {
+func (c *TestClient) ScanRegions(ctx context.Context, key, endKey []byte, limit int, _ ...opt.GetRegionOption) ([]*RegionInfo, error) {
 	if c.InjectErr && c.InjectTimes > 0 {
 		c.InjectTimes -= 1
 		return nil, status.Error(codes.Unavailable, "not leader")
@@ -646,6 +646,7 @@ func (f *FakeSplitClient) ScanRegions(
 	ctx context.Context,
 	startKey, endKey []byte,
 	limit int,
+	_ ...opt.GetRegionOption,
 ) ([]*RegionInfo, error) {
 	result := make([]*RegionInfo, 0)
 	count := 0

br/pkg/restore/split/split.go

@@ -18,6 +18,7 @@ import (
 	"github.com/pingcap/tidb/pkg/lightning/config"
 	"github.com/pingcap/tidb/pkg/util/codec"
 	"github.com/pingcap/tidb/pkg/util/redact"
+	"github.com/tikv/pd/client/opt"
 	"go.uber.org/zap"
 )
 
@@ -225,7 +226,12 @@ func PaginateScanRegion(
 		scanStartKey := startKey
 		for {
 			var batch []*RegionInfo
-			batch, err = client.ScanRegions(ctx, scanStartKey, endKey, limit)
+			if err != nil {
+				batch, err = client.ScanRegions(ctx, scanStartKey, endKey, limit)
+			} else {
+				batch, err = client.ScanRegions(ctx, scanStartKey, endKey, limit, opt.WithAllowFollowerHandle())
+			}
+
 			if err != nil {
 				err = errors.Annotatef(berrors.ErrPDBatchScanRegion.Wrap(err), "scan regions from start-key:%s, err: %s",
 					redact.Key(scanStartKey), err.Error())
@@ -306,7 +312,11 @@ func ScanRegionsWithRetry(
 	// because it's not easy to check multierr equals normal error.
 	// see https://github.com/pingcap/tidb/issues/33419.
 	_ = utils.WithRetry(ctx, func() error {
-		regions, err = client.ScanRegions(ctx, startKey, endKey, limit)
+		if err != nil {
+			regions, err = client.ScanRegions(ctx, startKey, endKey, limit)
+		} else {
+			regions, err = client.ScanRegions(ctx, startKey, endKey, limit, opt.WithAllowFollowerHandle())
+		}
 		if err != nil {
 			err = errors.Annotatef(berrors.ErrPDBatchScanRegion, "scan regions from start-key:%s, err: %s",
 				redact.Key(startKey), err.Error())

br/pkg/task/BUILD.bazel

@@ -63,6 +63,7 @@ go_library(
         "//pkg/parser/mysql",
         "//pkg/sessionctx/stmtctx",
         "//pkg/sessionctx/vardef",
+        "//pkg/sessionctx/variable",
         "//pkg/statistics/handle",
         "//pkg/tablecodec",
         "//pkg/types",

br/pkg/task/restore.go

@@ -45,6 +45,8 @@ import (
 	"github.com/pingcap/tidb/pkg/meta/model"
 	"github.com/pingcap/tidb/pkg/metrics"
 	"github.com/pingcap/tidb/pkg/parser/ast"
+	"github.com/pingcap/tidb/pkg/sessionctx/vardef"
+	"github.com/pingcap/tidb/pkg/sessionctx/variable"
 	"github.com/pingcap/tidb/pkg/tablecodec"
 	"github.com/pingcap/tidb/pkg/util"
 	"github.com/pingcap/tidb/pkg/util/codec"
@@ -808,6 +810,16 @@ func RunRestore(c context.Context, g glue.Glue, cmdName string, cfg *RestoreConf
 	defer mgr.Close()
 	defer cfg.CloseCheckpointMetaManager()
 
+	if err = g.UseOneShotSession(mgr.GetStorage(), false, func(se glue.Session) error {
+		enableFollowerHandleRegion, err := se.GetGlobalSysVar(vardef.PDEnableFollowerHandleRegion)
+		if err != nil {
+			return err
+		}
+		return mgr.SetFollowerHandle(variable.TiDBOptOn(enableFollowerHandleRegion))
+	}); err != nil {
+		return errors.Trace(err)
+	}
+
 	defer printRestoreMetrics()
 
 	var restoreError error

br/tests/br_incremental_ddl/run.sh

@@ -40,7 +40,7 @@ echo "full backup start..."
 run_br --pd $PD_ADDR backup table -s "local://$TEST_DIR/$DB/full" --db $DB -t $TABLE --log-file $LOG
 
 # when we backup, we should close domain in one shot session.
-# so we can check the log count of `one shot domain closed` to be 2.
+# so we can check the log count of `one shot domain closed` to be 1.
 # we will call UseOneShotSession once to get the value global variable.
 one_shot_session_count=$(cat $LOG | grep "one shot session closed" | wc -l | xargs)
 one_shot_domain_count=$(cat $LOG | grep "one shot domain closed" | wc -l | xargs)

pkg/lightning/backend/local/localhelper_test.go

@@ -30,6 +30,7 @@ import (
 	"github.com/pingcap/tidb/pkg/store/pdtypes"
 	"github.com/pingcap/tidb/pkg/util/codec"
 	"github.com/stretchr/testify/require"
+	"github.com/tikv/pd/client/opt"
 	"go.uber.org/atomic"
 )
 
@@ -167,7 +168,7 @@ func (c *testSplitClient) SplitWaitAndScatter(ctx context.Context, region *split
 	return newRegions, err
 }
 
-func (c *testSplitClient) ScanRegions(ctx context.Context, key, endKey []byte, limit int) ([]*split.RegionInfo, error) {
+func (c *testSplitClient) ScanRegions(ctx context.Context, key, endKey []byte, limit int, _ ...opt.GetRegionOption) ([]*split.RegionInfo, error) {
 	c.mu.Lock()
 	defer c.mu.Unlock()