diff --git a/pkg/ddl/index.go b/pkg/ddl/index.go
index 0f27f7604c..1e55ce4eb9 100644
--- a/pkg/ddl/index.go
+++ b/pkg/ddl/index.go
@@ -2937,10 +2937,8 @@ func checkDuplicateForUniqueIndex(ctx context.Context, t table.Table, reorgInfo
 
 // TaskKeyBuilder is used to build task key for the backfill job.
 type TaskKeyBuilder struct {
-	keyspace       string
 	multiSchemaSeq int32
 	mergeTempIdx   bool
-	jobID          int64
 }
 
 // NewTaskKeyBuilder creates a new TaskKeyBuilder.
diff --git a/pkg/executor/importer/precheck.go b/pkg/executor/importer/precheck.go
index 4476c9f8fe..3a6bcf22b4 100644
--- a/pkg/executor/importer/precheck.go
+++ b/pkg/executor/importer/precheck.go
@@ -17,7 +17,6 @@ package importer
 import (
 	"context"
 	"fmt"
-	"time"
 
 	"github.com/pingcap/errors"
 	"github.com/pingcap/tidb/br/pkg/storage"
@@ -32,10 +31,6 @@ import (
 	"github.com/pingcap/tidb/pkg/util/sqlexec"
 )
 
-const (
-	etcdDialTimeout = 5 * time.Second
-)
-
 // GetEtcdClient returns an etcd client.
 // exported for testing.
 var GetEtcdClient = store.NewEtcdCli
diff --git a/pkg/planner/core/logical_plan_builder.go b/pkg/planner/core/logical_plan_builder.go
index 01d67c1988..ca50b5beed 100644
--- a/pkg/planner/core/logical_plan_builder.go
+++ b/pkg/planner/core/logical_plan_builder.go
@@ -3669,16 +3669,6 @@ func (b *PlanBuilder) addAliasName(ctx context.Context, selectStmt *ast.SelectSt
 	return resultList, nil
 }
 
-func (b *PlanBuilder) pushHintWithoutTableWarning(hint *ast.TableOptimizerHint) {
-	var sb strings.Builder
-	ctx := format.NewRestoreCtx(0, &sb)
-	if err := hint.Restore(ctx); err != nil {
-		return
-	}
-	b.ctx.GetSessionVars().StmtCtx.SetHintWarning(
-		fmt.Sprintf("Hint %s is inapplicable. Please specify the table names in the arguments.", sb.String()))
-}
-
 func (b *PlanBuilder) pushTableHints(hints []*ast.TableOptimizerHint, currentLevel int) {
 	hints = b.hintProcessor.GetCurrentStmtHints(hints, currentLevel)
 	sessionVars := b.ctx.GetSessionVars()
diff --git a/pkg/planner/core/scalar_subq_expression.go b/pkg/planner/core/scalar_subq_expression.go
index 129e887c0d..e690613480 100644
--- a/pkg/planner/core/scalar_subq_expression.go
+++ b/pkg/planner/core/scalar_subq_expression.go
@@ -190,11 +190,6 @@ func (s *ScalarSubQueryExpr) Decorrelate(*expression.Schema) expression.Expressi
 	return s
 }
 
-// resolveIndices implements the Expression interface.
-func (*ScalarSubQueryExpr) resolveIndices(*expression.Schema) error {
-	return nil
-}
-
 // ResolveIndices implements the Expression interface.
 func (s *ScalarSubQueryExpr) ResolveIndices(_ *expression.Schema) (expression.Expression, error) {
 	return s, nil
@@ -205,11 +200,6 @@ func (s *ScalarSubQueryExpr) ResolveIndicesByVirtualExpr(_ expression.EvalContex
 	return s, false
 }
 
-// resolveIndicesByVirtualExpr implements the Expression interface.
-func (*ScalarSubQueryExpr) resolveIndicesByVirtualExpr(_ expression.EvalContext, _ *expression.Schema) bool {
-	return false
-}
-
 // RemapColumn implements the Expression interface.
 func (s *ScalarSubQueryExpr) RemapColumn(_ map[int64]*expression.Column) (expression.Expression, error) {
 	return s, nil
diff --git a/pkg/store/gcworker/gc_worker.go b/pkg/store/gcworker/gc_worker.go
index 9bf67448a4..27ef1b2b22 100644
--- a/pkg/store/gcworker/gc_worker.go
+++ b/pkg/store/gcworker/gc_worker.go
@@ -15,7 +15,6 @@
 package gcworker
 
 import (
-	"bytes"
 	"context"
 	"encoding/hex"
 	"fmt"
@@ -1143,20 +1142,6 @@ func (w *GCWorker) getStoresForGC(ctx context.Context) ([]*metapb.Store, error)
 	return upStores, nil
 }
 
-func (w *GCWorker) getStoresMapForGC(ctx context.Context) (map[uint64]*metapb.Store, error) {
-	stores, err := w.getStoresForGC(ctx)
-	if err != nil {
-		return nil, err
-	}
-
-	storesMap := make(map[uint64]*metapb.Store, len(stores))
-	for _, store := range stores {
-		storesMap[store.Id] = store
-	}
-
-	return storesMap, nil
-}
-
 func (w *GCWorker) loadGCConcurrencyWithDefault() (int, error) {
 	str, err := w.loadValueFromSysTable(gcConcurrencyKey)
 	if err != nil {
@@ -1409,52 +1394,6 @@ func (w *GCWorker) broadcastGCSafePoint(ctx context.Context, gcSafePoint uint64)
 	return nil
 }
 
-func (w *GCWorker) doGCForRange(ctx context.Context, startKey []byte, endKey []byte, safePoint uint64) (rangetask.TaskStat, error) {
-	var stat rangetask.TaskStat
-	defer func() {
-		metrics.GCActionRegionResultCounter.WithLabelValues("success").Add(float64(stat.CompletedRegions))
-		metrics.GCActionRegionResultCounter.WithLabelValues("fail").Add(float64(stat.FailedRegions))
-	}()
-	key := startKey
-	for {
-		bo := tikv.NewBackofferWithVars(ctx, gcOneRegionMaxBackoff, nil)
-		loc, err := w.tikvStore.GetRegionCache().LocateKey(bo, key)
-		if err != nil {
-			return stat, errors.Trace(err)
-		}
-
-		var regionErr *errorpb.Error
-		regionErr, err = w.doGCForRegion(bo, safePoint, loc.Region)
-
-		// we check regionErr here first, because we know 'regionErr' and 'err' should not return together, to keep it to
-		// make the process correct.
-		if regionErr != nil {
-			err = bo.Backoff(tikv.BoRegionMiss(), errors.New(regionErr.String()))
-			if err == nil {
-				continue
-			}
-		}
-
-		if err != nil {
-			logutil.BgLogger().Warn("[gc worker]",
-				zap.String("uuid", w.uuid),
-				zap.String("gc for range", fmt.Sprintf("[%d, %d)", startKey, endKey)),
-				zap.Uint64("safePoint", safePoint),
-				zap.Error(err))
-			stat.FailedRegions++
-		} else {
-			stat.CompletedRegions++
-		}
-
-		key = loc.EndKey
-		if len(key) == 0 || bytes.Compare(key, endKey) >= 0 {
-			break
-		}
-	}
-
-	return stat, nil
-}
-
 // doGCForRegion used for gc for region.
 // these two errors should not return together, for more, see the func 'doGC'
 func (w *GCWorker) doGCForRegion(bo *tikv.Backoffer, safePoint uint64, region tikv.RegionVerID) (*errorpb.Error, error) {