fixup

pingcap · Jul 15, 2022 · 1bf3b3a · 1bf3b3a
1 parent 911e7cc
commit 1bf3b3a
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diff --git a/planner/core/physical_plans.go b/planner/core/physical_plans.go
@@ -1295,6 +1295,11 @@ type PhysicalSelection struct {
 	basePhysicalPlan
 
 	Conditions []expression.Expression
+
+	// The flag indicates whether this Selection is from a DataSource.
+	// The flag is only used by cost model for compatibility and will be removed later.
+	// Please see https://github.com/pingcap/tidb/issues/36243 for more details.
+	fromDataSource bool
 }
 
 // Clone implements PhysicalPlan interface.

diff --git a/planner/core/plan_cost.go b/planner/core/plan_cost.go
@@ -81,6 +81,9 @@ func (p *PhysicalSelection) GetPlanCost(taskType property.TaskType, costFlag uin
 			return 0, errors.Errorf("unknown task type %v", taskType)
 		}
 		selfCost = getCardinality(p.children[0], costFlag) * cpuFactor
+		if p.fromDataSource {
+			selfCost = 0 // for compatibility, see https://github.com/pingcap/tidb/issues/36243
+		}
 	case modelVer2: // selection cost: rows * num-filters * cpu-factor
 		var cpuFactor float64
 		switch taskType {

diff --git a/planner/core/task.go b/planner/core/task.go
@@ -809,6 +809,7 @@ func (t *copTask) handleRootTaskConds(ctx sessionctx.Context, newTask *rootTask)
 			selectivity = SelectionFactor
 		}
 		sel := PhysicalSelection{Conditions: t.rootTaskConds}.Init(ctx, newTask.p.statsInfo().Scale(selectivity), newTask.p.SelectBlockOffset())
+		sel.fromDataSource = true
 		sel.SetChildren(newTask.p)
 		newTask.p = sel
 		sel.cost = newTask.cost()