diff --git a/build/nogo_config.json b/build/nogo_config.json
index 50806eef4fe08..06d746067620f 100644
--- a/build/nogo_config.json
+++ b/build/nogo_config.json
@@ -491,27 +491,18 @@
       ".*_test\\.go$": "ignore generated code",
       ".*_generated\\.go$": "ignore generated code",
       "planner/core/resolve_indices.go": "planner/core/resolve_indices.go",
-      "planner/core/rule_result_reorder.go": "planner/core/rule_result_reorder.go", 
-      "planner/core/rule_join_reorder_dp.go": "planner/core/rule_join_reorder_dp.go", 
-      "planner/core/plan_cache_param.go": "planner/core/plan_cache_param.go",
-      "planner/core/rule_predicate_push_down.go": "planner/core/rule_predicate_push_down.go", 
       "planner/core/rule_aggregation_push_down.go": "planner/core/rule_aggregation_push_down.go", 
-      "planner/core/rule_max_min_eliminate.go": "planner/core/rule_max_min_eliminate.go", 
-      "planner/core/rule_predicate_simplification.go": "planner/core/rule_predicate_simplification.go", 
+      "planner/core/rule_max_min_eliminate.go": "planner/core/rule_max_min_eliminate.go",
       "planner/core/indexmerge_path.go": "planner/core/indexmerge_path.go", 
       "planner/core/rule_join_reorder.go": "planner/core/rule_join_reorder.go", 
       "planner/core/plan_cacheable_checker.go": "planner/core/plan_cacheable_checker.go", 
       "planner/core/rule_decorrelate.go": "planner/core/rule_decorrelate.go", 
       "planner/core/plan_cache_utils.go": "planner/core/plan_cache_utils.go", 
       "planner/core/rule_aggregation_skew_rewrite.go": "planner/core/rule_aggregation_skew_rewrite.go", 
-      "planner/core/rule_topn_push_down.go": "planner/core/rule_topn_push_down.go", 
-      "planner/core/plan_cost_ver1.go": "planner/core/plan_cost_ver1.go", 
-      "planner/core/expression_rewriter.go": "planner/core/expression_rewriter.go", 
-      "planner/core/find_best_task.go": "planner/core/find_best_task.go", 
+      "planner/core/rule_topn_push_down.go": "planner/core/rule_topn_push_down.go",
+      "planner/core/expression_rewriter.go": "planner/core/expression_rewriter.go",
       "planner/core/task.go": "planner/core/task.go", 
-      "planner/core/preprocess.go": "planner/core/preprocess.go", 
-      "planner/core/rule_partition_processor.go": "planner/core/rule_partition_processor.go", 
-      "planner/core/exhaust_physical_plans.go": "planner/core/exhaust_physical_plans.go",
+      "planner/core/preprocess.go": "planner/core/preprocess.go",
       "planner/core/plan_cache_lru.go": "planner/core/plan_cache_lru.go", 
       "planner/core/common_plans.go": "planner/core/common_plans.go",
       "plugin/conn_ip_example/": "plugin/conn_ip_example/"
diff --git a/planner/core/exhaust_physical_plans.go b/planner/core/exhaust_physical_plans.go
index 6a59daa6af892..119c6497ac8e2 100644
--- a/planner/core/exhaust_physical_plans.go
+++ b/planner/core/exhaust_physical_plans.go
@@ -139,7 +139,7 @@ func (p *PhysicalMergeJoin) tryToGetChildReqProp(prop *property.PhysicalProperty
 	return []*property.PhysicalProperty{lProp, rProp}, true
 }
 
-func (p *LogicalJoin) checkJoinKeyCollation(leftKeys, rightKeys []*expression.Column) bool {
+func (*LogicalJoin) checkJoinKeyCollation(leftKeys, rightKeys []*expression.Column) bool {
 	// if a left key and its corresponding right key have different collation, don't use MergeJoin since
 	// the their children may sort their records in different ways
 	for i := range leftKeys {
@@ -1022,7 +1022,7 @@ func (ijHelper *indexJoinBuildHelper) buildRangeDecidedByInformation(idxCols []*
 func (p *LogicalJoin) constructInnerTableScanTask(
 	wrapper *indexJoinInnerChildWrapper,
 	ranges ranger.Ranges,
-	outerJoinKeys []*expression.Column,
+	_ []*expression.Column,
 	rangeInfo string,
 	keepOrder bool,
 	desc bool,
@@ -1115,7 +1115,7 @@ func (p *LogicalJoin) constructInnerByWrapper(wrapper *indexJoinInnerChildWrappe
 	return child
 }
 
-func (p *LogicalJoin) constructInnerSel(sel *LogicalSelection, child PhysicalPlan) PhysicalPlan {
+func (*LogicalJoin) constructInnerSel(sel *LogicalSelection, child PhysicalPlan) PhysicalPlan {
 	if sel == nil {
 		return child
 	}
@@ -1126,7 +1126,7 @@ func (p *LogicalJoin) constructInnerSel(sel *LogicalSelection, child PhysicalPla
 	return physicalSel
 }
 
-func (p *LogicalJoin) constructInnerProj(proj *LogicalProjection, child PhysicalPlan) PhysicalPlan {
+func (*LogicalJoin) constructInnerProj(proj *LogicalProjection, child PhysicalPlan) PhysicalPlan {
 	if proj == nil {
 		return child
 	}
@@ -1139,7 +1139,7 @@ func (p *LogicalJoin) constructInnerProj(proj *LogicalProjection, child Physical
 	return physicalProj
 }
 
-func (p *LogicalJoin) constructInnerUnionScan(us *LogicalUnionScan, reader PhysicalPlan) PhysicalPlan {
+func (*LogicalJoin) constructInnerUnionScan(us *LogicalUnionScan, reader PhysicalPlan) PhysicalPlan {
 	if us == nil {
 		return reader
 	}
@@ -1153,76 +1153,13 @@ func (p *LogicalJoin) constructInnerUnionScan(us *LogicalUnionScan, reader Physi
 	return physicalUnionScan
 }
 
-func getColsNDVLowerBoundFromHistColl(cols []*expression.Column, histColl *statistics.HistColl) int64 {
-	if len(cols) == 0 || histColl == nil {
-		return -1
-	}
-	colUIDs := make([]int64, len(cols))
-	for i, col := range cols {
-		colUIDs[i] = col.UniqueID
-	}
-
-	// Note that we don't need to specially handle prefix index in this function, because the NDV of a prefix index is
-	// equal or less than the corresponding normal index, and that's safe here since we want a lower bound.
-
-	// 1. Try to get NDV from column stats if it's a single column.
-	if len(colUIDs) == 1 && histColl.Columns != nil {
-		uid := colUIDs[0]
-		if colStats, ok := histColl.Columns[uid]; ok && colStats != nil {
-			return colStats.NDV
-		}
-	}
-
-	slices.Sort(colUIDs)
-	if histColl.Indices == nil || histColl.Idx2ColumnIDs == nil {
-		return -1
-	}
-
-	// 2. Try to get NDV from index stats.
-	for idxID, idxCols := range histColl.Idx2ColumnIDs {
-		if len(idxCols) != len(colUIDs) {
-			continue
-		}
-		orderedIdxCols := make([]int64, len(idxCols))
-		copy(orderedIdxCols, idxCols)
-		slices.Sort(orderedIdxCols)
-		if !slices.Equal(orderedIdxCols, colUIDs) {
-			continue
-		}
-		if idxStats, ok := histColl.Indices[idxID]; ok && idxStats != nil {
-			return idxStats.NDV
-		}
-	}
-
-	// TODO: if there's an index that contains the expected columns, we can also make use of its NDV.
-	// For example, NDV(a,b,c) / NDV(c) is a safe lower bound of NDV(a,b).
-
-	// 3. If we still haven't got an NDV, we use the minimal NDV in the column stats as a lower bound.
-	// This would happen when len(cols) > 1 and no proper index stats are available.
-	minNDV := int64(-1)
-	for _, colStats := range histColl.Columns {
-		if colStats == nil || colStats.Info == nil {
-			continue
-		}
-		col := colStats.Info
-		if col.IsGenerated() && !col.GeneratedStored {
-			continue
-		}
-		if (colStats.NDV > 0 && minNDV <= 0) ||
-			colStats.NDV < minNDV {
-			minNDV = colStats.NDV
-		}
-	}
-	return minNDV
-}
-
 // constructInnerIndexScanTask is specially used to construct the inner plan for PhysicalIndexJoin.
 func (p *LogicalJoin) constructInnerIndexScanTask(
 	wrapper *indexJoinInnerChildWrapper,
 	path *util.AccessPath,
 	ranges ranger.Ranges,
 	filterConds []expression.Expression,
-	innerJoinKeys []*expression.Column,
+	_ []*expression.Column,
 	rangeInfo string,
 	keepOrder bool,
 	desc bool,
@@ -2092,18 +2029,18 @@ func checkChildFitBC(p Plan) bool {
 	return p.SCtx().GetSessionVars().BroadcastJoinThresholdSize == -1 || sz < float64(p.SCtx().GetSessionVars().BroadcastJoinThresholdSize)
 }
 
-func calcBroadcastExchangeSize(p Plan, mppStoreCnt int) (float64, float64, bool) {
+func calcBroadcastExchangeSize(p Plan, mppStoreCnt int) (row float64, size float64, hasSize bool) {
 	s := p.statsInfo()
-	row := float64(s.Count()) * float64(mppStoreCnt-1)
+	row = float64(s.Count()) * float64(mppStoreCnt-1)
 	if s.HistColl == nil {
 		return row, 0, false
 	}
 	avg := s.HistColl.GetAvgRowSize(p.SCtx(), p.Schema().Columns, false, false)
-	size := avg * row
+	size = avg * row
 	return row, size, true
 }
 
-func calcBroadcastExchangeSizeByChild(p1 Plan, p2 Plan, mppStoreCnt int) (float64, float64, bool) {
+func calcBroadcastExchangeSizeByChild(p1 Plan, p2 Plan, mppStoreCnt int) (row float64, size float64, hasSize bool) {
 	row1, size1, hasSize1 := calcBroadcastExchangeSize(p1, mppStoreCnt)
 	row2, size2, hasSize2 := calcBroadcastExchangeSize(p2, mppStoreCnt)
 
@@ -2119,18 +2056,18 @@ func calcBroadcastExchangeSizeByChild(p1 Plan, p2 Plan, mppStoreCnt int) (float6
 	return math.Min(row1, row2), 0, false
 }
 
-func calcHashExchangeSize(p Plan, mppStoreCnt int) (float64, float64, bool) {
+func calcHashExchangeSize(p Plan, mppStoreCnt int) (row float64, sz float64, hasSize bool) {
 	s := p.statsInfo()
-	row := float64(s.Count()) * float64(mppStoreCnt-1) / float64(mppStoreCnt)
+	row = float64(s.Count()) * float64(mppStoreCnt-1) / float64(mppStoreCnt)
 	if s.HistColl == nil {
 		return row, 0, false
 	}
 	avg := s.HistColl.GetAvgRowSize(p.SCtx(), p.Schema().Columns, false, false)
-	sz := avg * row
+	sz = avg * row
 	return row, sz, true
 }
 
-func calcHashExchangeSizeByChild(p1 Plan, p2 Plan, mppStoreCnt int) (float64, float64, bool) {
+func calcHashExchangeSizeByChild(p1 Plan, p2 Plan, mppStoreCnt int) (row float64, size float64, hasSize bool) {
 	row1, size1, hasSize1 := calcHashExchangeSize(p1, mppStoreCnt)
 	row2, size2, hasSize2 := calcHashExchangeSize(p2, mppStoreCnt)
 
@@ -2867,7 +2804,7 @@ func (lw *LogicalWindow) exhaustPhysicalPlans(prop *property.PhysicalProperty) (
 }
 
 // exhaustPhysicalPlans is only for implementing interface. DataSource and Dual generate task in `findBestTask` directly.
-func (p *baseLogicalPlan) exhaustPhysicalPlans(_ *property.PhysicalProperty) ([]PhysicalPlan, bool, error) {
+func (*baseLogicalPlan) exhaustPhysicalPlans(*property.PhysicalProperty) ([]PhysicalPlan, bool, error) {
 	panic("baseLogicalPlan.exhaustPhysicalPlans() should never be called.")
 }
 
diff --git a/planner/core/find_best_task.go b/planner/core/find_best_task.go
index edd0f4a094daa..aefe19864fc2a 100644
--- a/planner/core/find_best_task.go
+++ b/planner/core/find_best_task.go
@@ -783,7 +783,7 @@ func (ds *DataSource) getIndexCandidate(path *util.AccessPath, prop *property.Ph
 	return candidate
 }
 
-func (ds *DataSource) getIndexMergeCandidate(path *util.AccessPath) *candidatePath {
+func (*DataSource) getIndexMergeCandidate(path *util.AccessPath) *candidatePath {
 	candidate := &candidatePath{path: path}
 	return candidate
 }
@@ -1123,9 +1123,9 @@ func (ds *DataSource) findBestTask(prop *property.PhysicalProperty, planCounter
 			if allRangeIsPoint {
 				var pointGetTask task
 				if len(path.Ranges) == 1 {
-					pointGetTask = ds.convertToPointGet(prop, candidate, opt)
+					pointGetTask = ds.convertToPointGet(prop, candidate)
 				} else {
-					pointGetTask = ds.convertToBatchPointGet(prop, candidate, hashPartColName, opt)
+					pointGetTask = ds.convertToBatchPointGet(prop, candidate, hashPartColName)
 				}
 
 				// Batch/PointGet plans may be over-optimized, like `a>=1(?) and a<=1(?)` --> `a=1` --> PointGet(a=1).
@@ -1213,7 +1213,7 @@ func (ds *DataSource) findBestTask(prop *property.PhysicalProperty, planCounter
 	return
 }
 
-func (ds *DataSource) isSafePointGetPlan4PlanCache(path *util.AccessPath) bool {
+func (*DataSource) isSafePointGetPlan4PlanCache(path *util.AccessPath) bool {
 	// PointGet might contain some over-optimized assumptions, like `a>=1 and a<=1` --> `a=1`, but
 	// these assumptions may be broken after parameters change.
 
@@ -2307,7 +2307,7 @@ func (ds *DataSource) convertToSampleTable(prop *property.PhysicalProperty,
 	}, nil
 }
 
-func (ds *DataSource) convertToPointGet(prop *property.PhysicalProperty, candidate *candidatePath, opt *physicalOptimizeOp) (task task) {
+func (ds *DataSource) convertToPointGet(prop *property.PhysicalProperty, candidate *candidatePath) (task task) {
 	if !prop.IsSortItemEmpty() && !candidate.isMatchProp {
 		return invalidTask
 	}
@@ -2384,8 +2384,7 @@ func (ds *DataSource) convertToPointGet(prop *property.PhysicalProperty, candida
 	return rTsk
 }
 
-func (ds *DataSource) convertToBatchPointGet(prop *property.PhysicalProperty,
-	candidate *candidatePath, hashPartColName *model.CIStr, opt *physicalOptimizeOp) (task task) {
+func (ds *DataSource) convertToBatchPointGet(prop *property.PhysicalProperty, candidate *candidatePath, hashPartColName *model.CIStr) (task task) {
 	if !prop.IsSortItemEmpty() && !candidate.isMatchProp {
 		return invalidTask
 	}
diff --git a/planner/core/plan_cache_param.go b/planner/core/plan_cache_param.go
index 9beae0a88e457..ca66199aa3c43 100644
--- a/planner/core/plan_cache_param.go
+++ b/planner/core/plan_cache_param.go
@@ -16,7 +16,6 @@ package core
 
 import (
 	"bytes"
-	"context"
 	"errors"
 	"sync"
 
@@ -83,7 +82,7 @@ func (pr *paramReplacer) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
 	return in, false
 }
 
-func (pr *paramReplacer) Leave(in ast.Node) (out ast.Node, ok bool) {
+func (*paramReplacer) Leave(in ast.Node) (out ast.Node, ok bool) {
 	return in, true
 }
 
@@ -94,9 +93,9 @@ func (pr *paramReplacer) Reset() {
 // GetParamSQLFromAST returns the parameterized SQL of this AST.
 // NOTICE: this function does not modify the original AST.
 // paramVals are copied from this AST.
-func GetParamSQLFromAST(ctx context.Context, sctx sessionctx.Context, stmt ast.StmtNode) (paramSQL string, paramVals []types.Datum, err error) {
+func GetParamSQLFromAST(sctx sessionctx.Context, stmt ast.StmtNode) (paramSQL string, paramVals []types.Datum, err error) {
 	var params []*driver.ValueExpr
-	paramSQL, params, err = ParameterizeAST(ctx, sctx, stmt)
+	paramSQL, params, err = ParameterizeAST(stmt)
 	if err != nil {
 		return "", nil, err
 	}
@@ -105,14 +104,14 @@ func GetParamSQLFromAST(ctx context.Context, sctx sessionctx.Context, stmt ast.S
 		p.Datum.Copy(&paramVals[i])
 	}
 
-	err = RestoreASTWithParams(ctx, sctx, stmt, params)
+	err = RestoreASTWithParams(sctx, stmt, params)
 	return
 }
 
 // ParameterizeAST parameterizes this StmtNode.
 // e.g. `select * from t where a<10 and b<23` --> `select * from t where a<? and b<?`, [10, 23].
 // NOTICE: this function may modify the input stmt.
-func ParameterizeAST(ctx context.Context, sctx sessionctx.Context, stmt ast.StmtNode) (paramSQL string, params []*driver.ValueExpr, err error) {
+func ParameterizeAST(stmt ast.StmtNode) (paramSQL string, params []*driver.ValueExpr, err error) {
 	pr := paramReplacerPool.Get().(*paramReplacer)
 	pCtx := paramCtxPool.Get().(*format.RestoreCtx)
 	defer func() {
@@ -135,8 +134,7 @@ type paramRestorer struct {
 }
 
 func (pr *paramRestorer) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
-	switch n := in.(type) {
-	case *driver.ParamMarkerExpr:
+	if n, ok := in.(*driver.ParamMarkerExpr); ok {
 		if n.Offset >= len(pr.params) {
 			pr.err = errors.New("failed to restore ast.Node")
 			return nil, true
@@ -152,7 +150,7 @@ func (pr *paramRestorer) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
 	return in, false
 }
 
-func (pr *paramRestorer) Leave(in ast.Node) (out ast.Node, ok bool) {
+func (*paramRestorer) Leave(in ast.Node) (out ast.Node, ok bool) {
 	return in, true
 }
 
@@ -162,7 +160,7 @@ func (pr *paramRestorer) Reset() {
 
 // RestoreASTWithParams restore this parameterized AST with specific parameters.
 // e.g. `select * from t where a<? and b<?`, [10, 23] --> `select * from t where a<10 and b<23`.
-func RestoreASTWithParams(ctx context.Context, _ sessionctx.Context, stmt ast.StmtNode, params []*driver.ValueExpr) error {
+func RestoreASTWithParams(_ sessionctx.Context, stmt ast.StmtNode, params []*driver.ValueExpr) error {
 	pr := paramRestorerPool.Get().(*paramRestorer)
 	defer func() {
 		pr.Reset()
diff --git a/planner/core/plan_cache_param_test.go b/planner/core/plan_cache_param_test.go
index cd98b3ac683d0..4009a9fa2c02a 100644
--- a/planner/core/plan_cache_param_test.go
+++ b/planner/core/plan_cache_param_test.go
@@ -15,7 +15,6 @@
 package core
 
 import (
-	"context"
 	"fmt"
 	"math/rand"
 	"sync"
@@ -28,7 +27,6 @@ import (
 )
 
 func TestParameterize(t *testing.T) {
-	sctx := MockContext()
 	cases := []struct {
 		sql      string
 		paramSQL string
@@ -112,7 +110,7 @@ func TestParameterize(t *testing.T) {
 	for _, c := range cases {
 		stmt, err := parser.New().ParseOneStmt(c.sql, "", "")
 		require.Nil(t, err)
-		paramSQL, params, err := ParameterizeAST(context.Background(), sctx, stmt)
+		paramSQL, params, err := ParameterizeAST(stmt)
 		require.Nil(t, err)
 		require.Equal(t, c.paramSQL, paramSQL)
 		require.Equal(t, len(c.params), len(params))
@@ -140,7 +138,7 @@ func TestGetParamSQLFromASTConcurrently(t *testing.T) {
 		wg.Add(1)
 		go func(id int) {
 			for i := 0; i < 1000; i++ {
-				_, vals, err := GetParamSQLFromAST(context.Background(), MockContext(), stmts[id])
+				_, vals, err := GetParamSQLFromAST(MockContext(), stmts[id])
 				require.Nil(t, err)
 				require.Equal(t, len(vals), 3)
 				require.Equal(t, vals[0].GetValue(), int64(id*3+0))
@@ -159,13 +157,12 @@ func BenchmarkParameterizeSelect(b *testing.B) {
 c_credit, c_credit_lim, c_discount, c_balance, c_since FROM customer WHERE c_w_id = ? AND c_d_id = ?AND c_id = ? FOR UPDATE`
 	stmt, err := parser.New().ParseOneStmt(paymentSelectCustomerForUpdate, "", "")
 	require.Nil(b, err)
-	sctx := MockContext()
-	_, _, err = ParameterizeAST(context.Background(), sctx, stmt)
+	_, _, err = ParameterizeAST(stmt)
 	require.Nil(b, err)
 
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		ParameterizeAST(context.Background(), sctx, stmt)
+		ParameterizeAST(stmt)
 	}
 }
 
@@ -173,13 +170,12 @@ func BenchmarkParameterizeInsert(b *testing.B) {
 	paymentInsertHistory := `INSERT INTO history (h_c_d_id, h_c_w_id, h_c_id, h_d_id, h_w_id, h_date, h_amount, h_data) VALUES (1, 2, 3, 4, 5, 6, 7, 8)`
 	stmt, err := parser.New().ParseOneStmt(paymentInsertHistory, "", "")
 	require.Nil(b, err)
-	sctx := MockContext()
-	_, _, err = ParameterizeAST(context.Background(), sctx, stmt)
+	_, _, err = ParameterizeAST(stmt)
 	require.Nil(b, err)
 
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		ParameterizeAST(context.Background(), sctx, stmt)
+		ParameterizeAST(stmt)
 	}
 }
 
@@ -191,6 +187,6 @@ func BenchmarkGetParamSQL(b *testing.B) {
 
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		GetParamSQLFromAST(context.Background(), sctx, stmt)
+		GetParamSQLFromAST(sctx, stmt)
 	}
 }
diff --git a/planner/core/plan_cost_ver1.go b/planner/core/plan_cost_ver1.go
index 8c5300574116b..156ac820837f9 100644
--- a/planner/core/plan_cost_ver1.go
+++ b/planner/core/plan_cost_ver1.go
@@ -172,7 +172,7 @@ func (p *PhysicalIndexLookUpReader) GetCost(costFlag uint64) (cost float64) {
 }
 
 // getPlanCostVer1 calculates the cost of the plan if it has not been calculated yet and returns the cost.
-func (p *PhysicalIndexLookUpReader) getPlanCostVer1(taskType property.TaskType, option *PlanCostOption) (float64, error) {
+func (p *PhysicalIndexLookUpReader) getPlanCostVer1(_ property.TaskType, option *PlanCostOption) (float64, error) {
 	costFlag := option.CostFlag
 	if p.planCostInit && !hasCostFlag(costFlag, CostFlagRecalculate) {
 		return p.planCost, nil
@@ -190,8 +190,9 @@ func (p *PhysicalIndexLookUpReader) getPlanCostVer1(taskType property.TaskType,
 
 	// to keep compatible with the previous cost implementation, re-calculate table-scan cost by using index stats-count again (see copTask.finishIndexPlan).
 	// TODO: amend table-side cost here later
-	var tmp PhysicalPlan
-	for tmp = p.tablePlan; len(tmp.Children()) > 0; tmp = tmp.Children()[0] {
+	var tmp = p.tablePlan
+	for len(tmp.Children()) > 0 {
+		tmp = tmp.Children()[0]
 	}
 	ts := tmp.(*PhysicalTableScan)
 	tblCost, err := ts.getPlanCostVer1(property.CopMultiReadTaskType, option)
@@ -226,7 +227,7 @@ func (p *PhysicalIndexLookUpReader) getPlanCostVer1(taskType property.TaskType,
 }
 
 // getPlanCostVer1 calculates the cost of the plan if it has not been calculated yet and returns the cost.
-func (p *PhysicalIndexReader) getPlanCostVer1(taskType property.TaskType, option *PlanCostOption) (float64, error) {
+func (p *PhysicalIndexReader) getPlanCostVer1(_ property.TaskType, option *PlanCostOption) (float64, error) {
 	costFlag := option.CostFlag
 	if p.planCostInit && !hasCostFlag(costFlag, CostFlagRecalculate) {
 		return p.planCost, nil
@@ -268,7 +269,7 @@ func (p *PhysicalIndexReader) GetNetDataSize() float64 {
 }
 
 // getPlanCostVer1 calculates the cost of the plan if it has not been calculated yet and returns the cost.
-func (p *PhysicalTableReader) getPlanCostVer1(taskType property.TaskType, option *PlanCostOption) (float64, error) {
+func (p *PhysicalTableReader) getPlanCostVer1(_ property.TaskType, option *PlanCostOption) (float64, error) {
 	costFlag := option.CostFlag
 	if p.planCostInit && !hasCostFlag(costFlag, CostFlagRecalculate) {
 		return p.planCost, nil
@@ -351,7 +352,7 @@ func (p *PhysicalTableReader) GetNetDataSize() float64 {
 }
 
 // getPlanCostVer1 calculates the cost of the plan if it has not been calculated yet and returns the cost.
-func (p *PhysicalIndexMergeReader) getPlanCostVer1(taskType property.TaskType, option *PlanCostOption) (float64, error) {
+func (p *PhysicalIndexMergeReader) getPlanCostVer1(_ property.TaskType, option *PlanCostOption) (float64, error) {
 	costFlag := option.CostFlag
 	if p.planCostInit && !hasCostFlag(costFlag, CostFlagRecalculate) {
 		return p.planCost, nil
@@ -405,7 +406,7 @@ func (p *PhysicalIndexMergeReader) GetPartialReaderNetDataSize(plan PhysicalPlan
 }
 
 // getPlanCostVer1 calculates the cost of the plan if it has not been calculated yet and returns the cost.
-func (p *PhysicalTableScan) getPlanCostVer1(taskType property.TaskType, option *PlanCostOption) (float64, error) {
+func (p *PhysicalTableScan) getPlanCostVer1(_ property.TaskType, option *PlanCostOption) (float64, error) {
 	costFlag := option.CostFlag
 	if p.planCostInit && !hasCostFlag(costFlag, CostFlagRecalculate) {
 		return p.planCost, nil
@@ -430,7 +431,7 @@ func (p *PhysicalTableScan) getPlanCostVer1(taskType property.TaskType, option *
 }
 
 // getPlanCostVer1 calculates the cost of the plan if it has not been calculated yet and returns the cost.
-func (p *PhysicalIndexScan) getPlanCostVer1(taskType property.TaskType, option *PlanCostOption) (float64, error) {
+func (p *PhysicalIndexScan) getPlanCostVer1(_ property.TaskType, option *PlanCostOption) (float64, error) {
 	costFlag := option.CostFlag
 	if p.planCostInit && !hasCostFlag(costFlag, CostFlagRecalculate) {
 		return p.planCost, nil
@@ -816,8 +817,8 @@ func (p *PhysicalMergeJoin) GetCost(lCnt, rCnt float64, costFlag uint64) float64
 	cpuCost += probeCost
 	// For merge join, only one group of rows with same join key(not null) are cached,
 	// we compute average memory cost using estimated group size.
-	NDV, _ := getColsNDVWithMatchedLen(innerKeys, innerSchema, innerStats)
-	memoryCost := (innerCnt / NDV) * sessVars.GetMemoryFactor()
+	ndv, _ := getColsNDVWithMatchedLen(innerKeys, innerSchema, innerStats)
+	memoryCost := (innerCnt / ndv) * sessVars.GetMemoryFactor()
 	return cpuCost + memoryCost
 }
 
@@ -841,7 +842,7 @@ func (p *PhysicalMergeJoin) getPlanCostVer1(taskType property.TaskType, option *
 }
 
 // GetCost computes cost of hash join operator itself.
-func (p *PhysicalHashJoin) GetCost(lCnt, rCnt float64, isMPP bool, costFlag uint64, op *physicalOptimizeOp) float64 {
+func (p *PhysicalHashJoin) GetCost(lCnt, rCnt float64, _ bool, costFlag uint64, op *physicalOptimizeOp) float64 {
 	buildCnt, probeCnt := lCnt, rCnt
 	build := p.children[0]
 	// Taking the right as the inner for right join or using the outer to build a hash table.
@@ -957,7 +958,7 @@ func (p *PhysicalHashJoin) getPlanCostVer1(taskType property.TaskType, option *P
 }
 
 // GetCost computes cost of stream aggregation considering CPU/memory.
-func (p *PhysicalStreamAgg) GetCost(inputRows float64, isRoot, isMPP bool, costFlag uint64) float64 {
+func (p *PhysicalStreamAgg) GetCost(inputRows float64, isRoot, _ bool, costFlag uint64) float64 {
 	aggFuncFactor := p.getAggFuncCostFactor(false)
 	var cpuCost float64
 	sessVars := p.ctx.GetSessionVars()
@@ -1144,7 +1145,7 @@ func (p *BatchPointGetPlan) GetCost(opt *physicalOptimizeOp) float64 {
 }
 
 // getPlanCostVer1 calculates the cost of the plan if it has not been calculated yet and returns the cost.
-func (p *BatchPointGetPlan) getPlanCostVer1(taskType property.TaskType, option *PlanCostOption) (float64, error) {
+func (p *BatchPointGetPlan) getPlanCostVer1(_ property.TaskType, option *PlanCostOption) (float64, error) {
 	costFlag := option.CostFlag
 	if p.planCostInit && !hasCostFlag(costFlag, CostFlagRecalculate) {
 		return p.planCost, nil
@@ -1192,7 +1193,7 @@ func (p *PointGetPlan) GetCost(opt *physicalOptimizeOp) float64 {
 }
 
 // getPlanCostVer1 calculates the cost of the plan if it has not been calculated yet and returns the cost.
-func (p *PointGetPlan) getPlanCostVer1(taskType property.TaskType, option *PlanCostOption) (float64, error) {
+func (p *PointGetPlan) getPlanCostVer1(_ property.TaskType, option *PlanCostOption) (float64, error) {
 	costFlag := option.CostFlag
 	if p.planCostInit && !hasCostFlag(costFlag, CostFlagRecalculate) {
 		return p.planCost, nil
diff --git a/planner/core/rule_join_reorder_dp.go b/planner/core/rule_join_reorder_dp.go
index dc13c59633146..9e87ced883fe3 100644
--- a/planner/core/rule_join_reorder_dp.go
+++ b/planner/core/rule_join_reorder_dp.go
@@ -138,7 +138,7 @@ func (s *joinReorderDPSolver) solve(joinGroup []LogicalPlan, tracer *joinReorder
 }
 
 // bfsGraph bfs a sub graph starting at startPos. And relabel its label for future use.
-func (s *joinReorderDPSolver) bfsGraph(startNode int, visited []bool, adjacents [][]int, nodeID2VisitID []int) []int {
+func (*joinReorderDPSolver) bfsGraph(startNode int, visited []bool, adjacents [][]int, nodeID2VisitID []int) []int {
 	queue := []int{startNode}
 	visited[startNode] = true
 	var visitID2NodeID []int
@@ -211,7 +211,7 @@ func (s *joinReorderDPSolver) dpGraph(visitID2NodeID, nodeID2VisitID []int, _ []
 	return bestPlan[(1<<nodeCnt)-1].p, nil
 }
 
-func (s *joinReorderDPSolver) nodesAreConnected(leftMask, rightMask uint, oldPos2NewPos []int,
+func (*joinReorderDPSolver) nodesAreConnected(leftMask, rightMask uint, oldPos2NewPos []int,
 	totalEqEdges []joinGroupEqEdge, totalNonEqEdges []joinGroupNonEqEdge) ([]joinGroupEqEdge, []expression.Expression) {
 	//nolint: prealloc
 	var usedEqEdges []joinGroupEqEdge
diff --git a/planner/core/rule_partition_processor.go b/planner/core/rule_partition_processor.go
index 57225e53368af..5c8537ea286a0 100644
--- a/planner/core/rule_partition_processor.go
+++ b/planner/core/rule_partition_processor.go
@@ -125,8 +125,7 @@ func generateHashPartitionExpr(ctx sessionctx.Context, pi *model.PartitionInfo,
 	return exprs[0], nil
 }
 
-func getPartColumnsForHashPartition(ctx sessionctx.Context, hashExpr expression.Expression,
-	columns []*expression.Column, names types.NameSlice) ([]*expression.Column, []int) {
+func getPartColumnsForHashPartition(hashExpr expression.Expression) ([]*expression.Column, []int) {
 	partCols := expression.ExtractColumns(hashExpr)
 	colLen := make([]int, 0, len(partCols))
 	for i := 0; i < len(partCols); i++ {
@@ -144,7 +143,7 @@ func (s *partitionProcessor) getUsedHashPartitions(ctx sessionctx.Context,
 	if err != nil {
 		return nil, nil, err
 	}
-	partCols, colLen := getPartColumnsForHashPartition(ctx, hashExpr, columns, names)
+	partCols, colLen := getPartColumnsForHashPartition(hashExpr)
 	detachedResult, err := ranger.DetachCondAndBuildRangeForPartition(ctx, conds, partCols, colLen, ctx.GetSessionVars().RangeMaxSize)
 	if err != nil {
 		return nil, nil, err
@@ -245,7 +244,7 @@ func (s *partitionProcessor) getUsedHashPartitions(ctx sessionctx.Context,
 
 func (s *partitionProcessor) getUsedKeyPartitions(ctx sessionctx.Context,
 	tbl table.Table, partitionNames []model.CIStr, columns []*expression.Column,
-	conds []expression.Expression, names types.NameSlice) ([]int, []expression.Expression, error) {
+	conds []expression.Expression, _ types.NameSlice) ([]int, []expression.Expression, error) {
 	pi := tbl.Meta().Partition
 	partExpr := tbl.(partitionTable).PartitionExpr()
 	partCols, colLen := partExpr.GetPartColumnsForKeyPartition(columns)
@@ -406,7 +405,7 @@ func (s *partitionProcessor) pruneHashOrKeyPartition(ctx sessionctx.Context, tbl
 // reconstructTableColNames reconstructs FieldsNames according to ds.TblCols.
 // ds.names may not match ds.TblCols since ds.names is pruned while ds.TblCols contains all original columns.
 // please see https://github.com/pingcap/tidb/issues/22635 for more details.
-func (s *partitionProcessor) reconstructTableColNames(ds *DataSource) ([]*types.FieldName, error) {
+func (*partitionProcessor) reconstructTableColNames(ds *DataSource) ([]*types.FieldName, error) {
 	names := make([]*types.FieldName, 0, len(ds.TblCols))
 	// Use DeletableCols to get all the columns.
 	colsInfo := ds.table.DeletableCols()
@@ -486,8 +485,7 @@ type listPartitionPruner struct {
 	listPrune      *tables.ForListPruning
 }
 
-func newListPartitionPruner(ctx sessionctx.Context, tbl table.Table, partitionNames []model.CIStr,
-	s *partitionProcessor, conds []expression.Expression, pruneList *tables.ForListPruning, columns []*expression.Column) *listPartitionPruner {
+func newListPartitionPruner(ctx sessionctx.Context, tbl table.Table, partitionNames []model.CIStr, s *partitionProcessor, pruneList *tables.ForListPruning, columns []*expression.Column) *listPartitionPruner {
 	pruneList = pruneList.Clone()
 	for i := range pruneList.PruneExprCols {
 		for j := range columns {
@@ -723,7 +721,7 @@ func (s *partitionProcessor) findUsedListPartitions(ctx sessionctx.Context, tbl
 	pi := tbl.Meta().Partition
 	partExpr := tbl.(partitionTable).PartitionExpr()
 
-	listPruner := newListPartitionPruner(ctx, tbl, partitionNames, s, conds, partExpr.ForListPruning, columns)
+	listPruner := newListPartitionPruner(ctx, tbl, partitionNames, s, partExpr.ForListPruning, columns)
 	var used map[int]struct{}
 	var err error
 	if partExpr.ForListPruning.ColPrunes == nil {
@@ -781,7 +779,7 @@ func (s *partitionProcessor) prune(ds *DataSource, opt *logicalOptimizeOp) (Logi
 }
 
 // findByName checks whether object name exists in list.
-func (s *partitionProcessor) findByName(partitionNames []model.CIStr, partitionName string) bool {
+func (*partitionProcessor) findByName(partitionNames []model.CIStr, partitionName string) bool {
 	for _, s := range partitionNames {
 		if s.L == partitionName {
 			return true
@@ -932,8 +930,7 @@ func (or partitionRangeOR) intersection(x partitionRangeOR) partitionRangeOR {
 }
 
 // intersectionRange calculate the intersection of [start, end) and [newStart, newEnd)
-func intersectionRange(start, end, newStart, newEnd int) (int, int) {
-	var s, e int
+func intersectionRange(start, end, newStart, newEnd int) (s int, e int) {
 	if start > newStart {
 		s = start
 	} else {
@@ -1268,7 +1265,7 @@ type rangePruner struct {
 	monotonous monotoneMode
 }
 
-func (p *rangePruner) partitionRangeForExpr(sctx sessionctx.Context, expr expression.Expression) (int, int, bool) {
+func (p *rangePruner) partitionRangeForExpr(sctx sessionctx.Context, expr expression.Expression) (start int, end int, ok bool) {
 	if constExpr, ok := expr.(*expression.Constant); ok {
 		if b, err := constExpr.Value.ToBool(sctx.GetSessionVars().StmtCtx); err == nil && b == 0 {
 			// A constant false expression.
@@ -1282,7 +1279,7 @@ func (p *rangePruner) partitionRangeForExpr(sctx sessionctx.Context, expr expres
 	}
 
 	unsigned := mysql.HasUnsignedFlag(p.col.RetType.GetFlag())
-	start, end := pruneUseBinarySearch(p.lessThan, dataForPrune, unsigned)
+	start, end = pruneUseBinarySearch(p.lessThan, dataForPrune, unsigned)
 	return start, end, true
 }
 
@@ -1586,7 +1583,7 @@ func pruneUseBinarySearch(lessThan lessThanDataInt, data dataForPrune, unsigned
 	return start, end
 }
 
-func (s *partitionProcessor) resolveAccessPaths(ds *DataSource) error {
+func (*partitionProcessor) resolveAccessPaths(ds *DataSource) error {
 	possiblePaths, err := getPossibleAccessPaths(
 		ds.ctx, &tableHintInfo{indexMergeHintList: ds.indexMergeHints, indexHintList: ds.IndexHints},
 		ds.astIndexHints, ds.table, ds.DBName, ds.tableInfo.Name, ds.isForUpdateRead, true)
@@ -1686,7 +1683,7 @@ func appendWarnForUnknownPartitions(ctx sessionctx.Context, hintName string, unk
 	ctx.GetSessionVars().StmtCtx.AppendWarning(warning)
 }
 
-func (s *partitionProcessor) checkHintsApplicable(ds *DataSource, partitionSet set.StringSet) {
+func (*partitionProcessor) checkHintsApplicable(ds *DataSource, partitionSet set.StringSet) {
 	for _, idxHint := range ds.IndexHints {
 		unknownPartitions := checkTableHintsApplicableForPartition(idxHint.partitions, partitionSet)
 		appendWarnForUnknownPartitions(ds.ctx, restore2IndexHint(idxHint.hintTypeString(), idxHint), unknownPartitions)
@@ -1756,7 +1753,7 @@ func (s *partitionProcessor) makeUnionAllChildren(ds *DataSource, pi *model.Part
 	return unionAll, nil
 }
 
-func (s *partitionProcessor) pruneRangeColumnsPartition(ctx sessionctx.Context, conds []expression.Expression, pi *model.PartitionInfo, pe *tables.PartitionExpr, columns []*expression.Column) (partitionRangeOR, error) {
+func (*partitionProcessor) pruneRangeColumnsPartition(ctx sessionctx.Context, conds []expression.Expression, pi *model.PartitionInfo, pe *tables.PartitionExpr, columns []*expression.Column) (partitionRangeOR, error) {
 	result := fullRange(len(pi.Definitions))
 
 	if len(pi.Columns) < 1 {
@@ -1816,7 +1813,7 @@ func (p *rangeColumnsPruner) getPartCol(colID int64) *expression.Column {
 	return nil
 }
 
-func (p *rangeColumnsPruner) partitionRangeForExpr(sctx sessionctx.Context, expr expression.Expression) (int, int, bool) {
+func (p *rangeColumnsPruner) partitionRangeForExpr(sctx sessionctx.Context, expr expression.Expression) (start int, end int, ok bool) {
 	op, ok := expr.(*expression.ScalarFunction)
 	if !ok {
 		return 0, len(p.lessThan), false
@@ -1867,7 +1864,7 @@ func (p *rangeColumnsPruner) partitionRangeForExpr(sctx sessionctx.Context, expr
 	if exprColl != colColl && (opName != ast.EQ || !collate.IsBinCollation(exprColl)) {
 		return 0, len(p.lessThan), true
 	}
-	start, end := p.pruneUseBinarySearch(sctx, opName, con)
+	start, end = p.pruneUseBinarySearch(sctx, opName, con)
 	return start, end, true
 }
 
diff --git a/planner/core/rule_predicate_push_down.go b/planner/core/rule_predicate_push_down.go
index e3df3c6245f18..6e08aa65c91af 100644
--- a/planner/core/rule_predicate_push_down.go
+++ b/planner/core/rule_predicate_push_down.go
@@ -42,7 +42,7 @@ type exprPrefixAdder struct {
 	lengths   []int
 }
 
-func (s *ppdSolver) optimize(_ context.Context, lp LogicalPlan, opt *logicalOptimizeOp) (LogicalPlan, error) {
+func (*ppdSolver) optimize(_ context.Context, lp LogicalPlan, opt *logicalOptimizeOp) (LogicalPlan, error) {
 	_, p := lp.PredicatePushDown(nil, opt)
 	return p, nil
 }
@@ -896,17 +896,17 @@ func (ds *DataSource) AddPrefix4ShardIndexes(sc sessionctx.Context, conds []expr
 
 func (ds *DataSource) addExprPrefixCond(sc sessionctx.Context, path *util.AccessPath,
 	conds []expression.Expression) ([]expression.Expression, error) {
-	IdxCols, IdxColLens :=
+	idxCols, idxColLens :=
 		expression.IndexInfo2PrefixCols(ds.Columns, ds.schema.Columns, path.Index)
-	if len(IdxCols) == 0 {
+	if len(idxCols) == 0 {
 		return conds, nil
 	}
 
 	adder := &exprPrefixAdder{
 		sctx:      sc,
 		OrigConds: conds,
-		cols:      IdxCols,
-		lengths:   IdxColLens,
+		cols:      idxCols,
+		lengths:   idxColLens,
 	}
 
 	return adder.addExprPrefix4ShardIndex()
diff --git a/planner/core/rule_predicate_simplification.go b/planner/core/rule_predicate_simplification.go
index 87231ccd35fa0..403b212885fcc 100644
--- a/planner/core/rule_predicate_simplification.go
+++ b/planner/core/rule_predicate_simplification.go
@@ -65,7 +65,7 @@ func findPredicateType(expr expression.Expression) (*expression.Column, predicat
 	return nil, otherPredicate
 }
 
-func (s *predicateSimplification) optimize(_ context.Context, p LogicalPlan, opt *logicalOptimizeOp) (LogicalPlan, error) {
+func (*predicateSimplification) optimize(_ context.Context, p LogicalPlan, opt *logicalOptimizeOp) (LogicalPlan, error) {
 	return p.predicateSimplification(opt), nil
 }
 
@@ -154,8 +154,8 @@ func applyPredicateSimplification(sctx sessionctx.Context, predicates []expressi
 	return newValues
 }
 
-func (s *DataSource) predicateSimplification(opt *logicalOptimizeOp) LogicalPlan {
-	p := s.self.(*DataSource)
+func (ds *DataSource) predicateSimplification(*logicalOptimizeOp) LogicalPlan {
+	p := ds.self.(*DataSource)
 	p.pushedDownConds = applyPredicateSimplification(p.ctx, p.pushedDownConds)
 	p.allConds = applyPredicateSimplification(p.ctx, p.allConds)
 	return p
diff --git a/planner/core/rule_result_reorder.go b/planner/core/rule_result_reorder.go
index a182501cc05e1..afb17b487d123 100644
--- a/planner/core/rule_result_reorder.go
+++ b/planner/core/rule_result_reorder.go
@@ -93,7 +93,7 @@ func (rs *resultReorder) injectSort(lp LogicalPlan) LogicalPlan {
 	return sort
 }
 
-func (rs *resultReorder) isInputOrderKeeper(lp LogicalPlan) bool {
+func (*resultReorder) isInputOrderKeeper(lp LogicalPlan) bool {
 	switch lp.(type) {
 	case *LogicalSelection, *LogicalProjection, *LogicalLimit:
 		return true
@@ -123,6 +123,6 @@ func (rs *resultReorder) extractHandleCol(lp LogicalPlan) *expression.Column {
 	return nil
 }
 
-func (rs *resultReorder) name() string {
+func (*resultReorder) name() string {
 	return "result_reorder"
 }
diff --git a/planner/optimize.go b/planner/optimize.go
index 6312b3681ed50..26e0b34a31ce3 100644
--- a/planner/optimize.go
+++ b/planner/optimize.go
@@ -97,7 +97,7 @@ func getPlanFromNonPreparedPlanCache(ctx context.Context, sctx sessionctx.Contex
 		return nil, nil, false, nil
 	}
 
-	paramSQL, paramsVals, err := core.GetParamSQLFromAST(ctx, sctx, stmt)
+	paramSQL, paramsVals, err := core.GetParamSQLFromAST(sctx, stmt)
 	if err != nil {
 		return nil, nil, false, err
 	}