planner: show operator cost formulas under 'explain format=true_card_cost'

planner/core/common_plans.go

@@ -562,12 +562,14 @@ func (e *Explain) prepareSchema() error {
 	switch {
 	case (format == types.ExplainFormatROW || format == types.ExplainFormatBrief) && (!e.Analyze && e.RuntimeStatsColl == nil):
 		fieldNames = []string{"id", "estRows", "task", "access object", "operator info"}
-	case format == types.ExplainFormatVerbose || format == types.ExplainFormatTrueCardCost:
+	case format == types.ExplainFormatVerbose:
 		if e.Analyze || e.RuntimeStatsColl != nil {
 			fieldNames = []string{"id", "estRows", "estCost", "actRows", "task", "access object", "execution info", "operator info", "memory", "disk"}
 		} else {
 			fieldNames = []string{"id", "estRows", "estCost", "task", "access object", "operator info"}
 		}
+	case format == types.ExplainFormatTrueCardCost:
+		fieldNames = []string{"id", "estRows", "estCost", "costFormula", "actRows", "task", "access object", "execution info", "operator info", "memory", "disk"}
 	case (format == types.ExplainFormatROW || format == types.ExplainFormatBrief) && (e.Analyze || e.RuntimeStatsColl != nil):
 		fieldNames = []string{"id", "estRows", "actRows", "task", "access object", "execution info", "operator info", "memory", "disk"}
 	case format == types.ExplainFormatDOT:
@@ -746,14 +748,17 @@ func (e *Explain) prepareOperatorInfo(p Plan, taskType, id string) {
 		return
 	}
 
-	estRows, estCost, accessObject, operatorInfo := e.getOperatorInfo(p, id)
+	estRows, estCost, costFormula, accessObject, operatorInfo := e.getOperatorInfo(p, id)
 
 	var row []string
 	if e.Analyze || e.RuntimeStatsColl != nil {
 		row = []string{id, estRows}
 		if strings.ToLower(e.Format) == types.ExplainFormatVerbose || strings.ToLower(e.Format) == types.ExplainFormatTrueCardCost {
 			row = append(row, estCost)
 		}
+		if strings.ToLower(e.Format) == types.ExplainFormatTrueCardCost {
+			row = append(row, costFormula)
+		}
 		actRows, analyzeInfo, memoryInfo, diskInfo := getRuntimeInfoStr(e.ctx, p, e.RuntimeStatsColl)
 		row = append(row, actRows, taskType, accessObject, analyzeInfo, operatorInfo, memoryInfo, diskInfo)
 	} else {
@@ -766,24 +771,31 @@ func (e *Explain) prepareOperatorInfo(p Plan, taskType, id string) {
 	e.Rows = append(e.Rows, row)
 }
 
-func (e *Explain) getOperatorInfo(p Plan, id string) (string, string, string, string) {
+func (e *Explain) getOperatorInfo(p Plan, id string) (string, string, string, string, string) {
 	// For `explain for connection` statement, `e.ExplainRows` will be set.
 	for _, row := range e.ExplainRows {
 		if len(row) < 5 {
 			panic("should never happen")
 		}
 		if row[0] == id {
-			return row[1], "N/A", row[3], row[4]
+			return row[1], "N/A", "N/A", row[3], row[4]
 		}
 	}
 	estRows := "N/A"
 	if si := p.statsInfo(); si != nil {
 		estRows = strconv.FormatFloat(si.RowCount, 'f', 2, 64)
 	}
 	estCost := "N/A"
+	costFormula := "N/A"
 	if pp, ok := p.(PhysicalPlan); ok {
-		planCost, _ := getPlanCost(pp, property.RootTaskType, NewDefaultPlanCostOption())
-		estCost = strconv.FormatFloat(planCost, 'f', 2, 64)
+		if e.ctx != nil && e.ctx.GetSessionVars().CostModelVersion == modelVer2 {
+			costVer2, _ := pp.getPlanCostVer2(property.RootTaskType, NewDefaultPlanCostOption())
+			estCost = strconv.FormatFloat(costVer2.cost, 'f', 2, 64)
+			costFormula = costVer2.formula
+		} else {
+			planCost, _ := getPlanCost(pp, property.RootTaskType, NewDefaultPlanCostOption())
+			estCost = strconv.FormatFloat(planCost, 'f', 2, 64)
+		}
 	}
 	var accessObject, operatorInfo string
 	if plan, ok := p.(dataAccesser); ok {
@@ -795,7 +807,7 @@ func (e *Explain) getOperatorInfo(p Plan, id string) (string, string, string, st
 		}
 		operatorInfo = p.ExplainInfo()
 	}
-	return estRows, estCost, accessObject, operatorInfo
+	return estRows, estCost, costFormula, accessObject, operatorInfo
 }
 
 // BinaryPlanStrFromFlatPlan generates the compressed and encoded binary plan from a FlatPhysicalPlan.

planner/core/plan_cost_ver2.go

@@ -54,7 +54,7 @@ func (p *basePhysicalPlan) getPlanCostVer2(taskType property.TaskType, option *P
 		p.planCostVer2 = sumCostVer2(childCosts...)
 	}
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -76,7 +76,7 @@ func (p *PhysicalSelection) getPlanCostVer2(taskType property.TaskType, option *
 
 	p.planCostVer2 = sumCostVer2(filterCost, childCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -100,7 +100,7 @@ func (p *PhysicalProjection) getPlanCostVer2(taskType property.TaskType, option
 
 	p.planCostVer2 = sumCostVer2(childCost, divCostVer2(projCost, concurrency))
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -117,7 +117,7 @@ func (p *PhysicalIndexScan) getPlanCostVer2(taskType property.TaskType, option *
 
 	p.planCostVer2 = scanCostVer2(option, rows, rowSize, scanFactor)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -140,7 +140,7 @@ func (p *PhysicalTableScan) getPlanCostVer2(taskType property.TaskType, option *
 	}
 
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -168,7 +168,7 @@ func (p *PhysicalIndexReader) getPlanCostVer2(taskType property.TaskType, option
 
 	p.planCostVer2 = divCostVer2(sumCostVer2(childCost, netCost, seekCost), concurrency)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -203,7 +203,7 @@ func (p *PhysicalTableReader) getPlanCostVer2(taskType property.TaskType, option
 		!hasCostFlag(option.CostFlag, CostFlagRecalculate) { // show the real cost in explain-statements
 		p.planCostVer2 = divCostVer2(p.planCostVer2, 1000000000)
 	}
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -259,7 +259,7 @@ func (p *PhysicalIndexLookUpReader) getPlanCostVer2(taskType property.TaskType,
 
 	p.planCostVer2 = sumCostVer2(indexSideCost, divCostVer2(sumCostVer2(tableSideCost, doubleReadCost), doubleReadConcurrency))
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -307,7 +307,7 @@ func (p *PhysicalIndexMergeReader) getPlanCostVer2(taskType property.TaskType, o
 
 	p.planCostVer2 = sumCostVer2(tableSideCost, sumIndexSideCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -362,7 +362,7 @@ func (p *PhysicalSort) getPlanCostVer2(taskType property.TaskType, option *PlanC
 
 	p.planCostVer2 = sumCostVer2(childCost, sortCPUCost, sortMemCost, sortDiskCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -394,7 +394,7 @@ func (p *PhysicalTopN) getPlanCostVer2(taskType property.TaskType, option *PlanC
 
 	p.planCostVer2 = sumCostVer2(childCost, topNCPUCost, topNMemCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -417,7 +417,7 @@ func (p *PhysicalStreamAgg) getPlanCostVer2(taskType property.TaskType, option *
 
 	p.planCostVer2 = sumCostVer2(childCost, aggCost, groupCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -446,7 +446,7 @@ func (p *PhysicalHashAgg) getPlanCostVer2(taskType property.TaskType, option *Pl
 
 	p.planCostVer2 = sumCostVer2(childCost, divCostVer2(sumCostVer2(aggCost, groupCost, hashBuildCost, hashProbeCost), concurrency))
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -476,7 +476,7 @@ func (p *PhysicalMergeJoin) getPlanCostVer2(taskType property.TaskType, option *
 
 	p.planCostVer2 = sumCostVer2(leftChildCost, rightChildCost, filterCost, groupCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -520,7 +520,7 @@ func (p *PhysicalHashJoin) getPlanCostVer2(taskType property.TaskType, option *P
 	p.planCostVer2 = sumCostVer2(buildChildCost, probeChildCost, buildHashCost, buildFilterCost,
 		divCostVer2(sumCostVer2(probeFilterCost, probeHashCost), concurrency))
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -560,7 +560,7 @@ func (p *PhysicalIndexJoin) getPlanCostVer2(taskType property.TaskType, option *
 
 	p.planCostVer2 = sumCostVer2(buildChildCost, buildFilterCost, divCostVer2(sumCostVer2(probeCost, probeFilterCost), probeConcurrency))
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 func (p *PhysicalIndexHashJoin) getPlanCostVer2(taskType property.TaskType, option *PlanCostOption) (costVer2, error) {
@@ -601,7 +601,7 @@ func (p *PhysicalApply) getPlanCostVer2(taskType property.TaskType, option *Plan
 
 	p.planCostVer2 = sumCostVer2(buildChildCost, buildFilterCost, probeCost, probeFilterCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 calculates the cost of the plan if it has not been calculated yet and returns the cost.
@@ -622,7 +622,7 @@ func (p *PhysicalUnionAll) getPlanCostVer2(taskType property.TaskType, option *P
 	}
 	p.planCostVer2 = divCostVer2(sumCostVer2(childCosts...), concurrency)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -644,7 +644,7 @@ func (p *PhysicalExchangeReceiver) getPlanCostVer2(taskType property.TaskType, o
 
 	p.planCostVer2 = sumCostVer2(childCost, netCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -668,7 +668,7 @@ func (p *PointGetPlan) getPlanCostVer2(taskType property.TaskType, option *PlanC
 
 	p.planCostVer2 = sumCostVer2(netCost, seekCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 // getPlanCostVer2 returns the plan-cost of this sub-plan, which is:
@@ -693,7 +693,7 @@ func (p *BatchPointGetPlan) getPlanCostVer2(taskType property.TaskType, option *
 
 	p.planCostVer2 = sumCostVer2(netCost, seekCost)
 	p.planCostInit = true
-	return p.planCostVer2, nil
+	return p.planCostVer2.label(p), nil
 }
 
 func scanCostVer2(option *PlanCostOption, rows, rowSize float64, scanFactor costVer2Factor) costVer2 {
@@ -929,6 +929,14 @@ type costVer2 struct {
 	formula     string             // It used to trace the cost calculation.
 }
 
+func (c costVer2) label(p PhysicalPlan) costVer2 {
+	if !c.trace {
+		return c
+	}
+	c.formula = p.ExplainID().String()
+	return c
+}
+
 func traceCost(option *PlanCostOption) bool {
 	if option != nil && hasCostFlag(option.CostFlag, CostFlagTrace) {
 		return true

planner/core/plan_cost_ver2_test.go

@@ -129,6 +129,28 @@ func TestCostModelVer2(t *testing.T) {
 	}
 }
 
+func TestCostModelShowFormula(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec(`create table t (a int)`)
+	tk.MustExec("insert into t values (1), (2), (3)")
+	tk.MustExec("set @@tidb_cost_model_version=2")
+
+	tk.MustExecToErr("explain format='true_card_cost' select * from t") // 'true_card_cost' must work with 'explain analyze'
+	plan := tk.MustQuery("explain analyze format='true_card_cost' select * from t where a<3").Rows()
+	actual := make([][]interface{}, 0, len(plan))
+	for _, row := range plan {
+		actual = append(actual, []interface{}{row[0], row[3]}) // id,costFormula
+		fmt.Println(actual)
+	}
+	require.Equal(t, actual, [][]interface{}{
+		{"TableReader_7", "((Selection_6) + (net(2*rowsize(16)*tidb_kv_net_factor(8))) + (seek(tasks(20)*tidb_request_factor(9.5e+06))))/15"},
+		{"└─Selection_6", "(cpu(3*filters(1)*tikv_cpu_factor(30))) + (TableFullScan_5)"},
+		{"  └─TableFullScan_5", "scan(3*logrowsize(29)*tikv_scan_factor(100))"},
+	})
+}
+
 func TestCostModelTraceVer2(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)

planner/core/planbuilder.go

@@ -4641,6 +4641,10 @@ func (b *PlanBuilder) buildTrace(trace *ast.TraceStmt) (Plan, error) {
 }
 
 func (b *PlanBuilder) buildExplainPlan(targetPlan Plan, format string, explainRows [][]string, analyze bool, execStmt ast.StmtNode, runtimeStats *execdetails.RuntimeStatsColl) (Plan, error) {
+	if strings.ToLower(format) == types.ExplainFormatTrueCardCost && !analyze {
+		return nil, errors.Errorf("'explain format=%v' cannot work without 'analyze', please use 'explain analyze format=%v'", format, format)
+	}
+
 	p := &Explain{
 		TargetPlan:       targetPlan,
 		Format:           format,