planner: Make temporary table calculate right cost for cascades optim…

…izer (#25958)
pingcap · Jul 7, 2021 · 297a90d · 297a90d
1 parent c043d66
commit 297a90d
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Showing 2 changed files with 13 additions and 8 deletions.
diff --git a/planner/cascades/implementation_rules.go b/planner/cascades/implementation_rules.go
@@ -175,10 +175,10 @@ func (r *ImplTiKVSingleReadGather) OnImplement(expr *memo.GroupExpr, reqProp *pr
 	sg := expr.ExprNode.(*plannercore.TiKVSingleGather)
 	if sg.IsIndexGather {
 		reader := sg.GetPhysicalIndexReader(logicProp.Schema, logicProp.Stats.ScaleByExpectCnt(reqProp.ExpectedCnt), reqProp)
-		return []memo.Implementation{impl.NewIndexReaderImpl(reader, sg.Source.TblColHists)}, nil
+		return []memo.Implementation{impl.NewIndexReaderImpl(reader, sg.Source)}, nil
 	}
 	reader := sg.GetPhysicalTableReader(logicProp.Schema, logicProp.Stats.ScaleByExpectCnt(reqProp.ExpectedCnt), reqProp)
-	return []memo.Implementation{impl.NewTableReaderImpl(reader, sg.Source.TblColHists)}, nil
+	return []memo.Implementation{impl.NewTableReaderImpl(reader, sg.Source)}, nil
 }
 
 // ImplTableScan implements TableScan as PhysicalTableScan.

diff --git a/planner/implementation/datasource.go b/planner/implementation/datasource.go
@@ -16,6 +16,7 @@ package implementation
 import (
 	"math"
 
+	"github.com/pingcap/parser/model"
 	"github.com/pingcap/tidb/expression"
 	"github.com/pingcap/tidb/kv"
 	plannercore "github.com/pingcap/tidb/planner/core"
@@ -56,15 +57,17 @@ func (impl *MemTableScanImpl) CalcCost(outCount float64, children ...memo.Implem
 // TableReaderImpl implementation of PhysicalTableReader.
 type TableReaderImpl struct {
 	baseImpl
+	tblInfo     *model.TableInfo
 	tblColHists *statistics.HistColl
 }
 
 // NewTableReaderImpl creates a new table reader Implementation.
-func NewTableReaderImpl(reader *plannercore.PhysicalTableReader, hists *statistics.HistColl) *TableReaderImpl {
+func NewTableReaderImpl(reader *plannercore.PhysicalTableReader, source *plannercore.DataSource) *TableReaderImpl {
 	base := baseImpl{plan: reader}
 	impl := &TableReaderImpl{
 		baseImpl:    base,
-		tblColHists: hists,
+		tblInfo:     source.TableInfo(),
+		tblColHists: source.TblColHists,
 	}
 	return impl
 }
@@ -76,7 +79,7 @@ func (impl *TableReaderImpl) CalcCost(outCount float64, children ...memo.Impleme
 	sessVars := reader.SCtx().GetSessionVars()
 	// TableReaderImpl don't have tableInfo property, so using nil to replace it.
 	// Todo add the tableInfo property for the TableReaderImpl.
-	networkCost := outCount * sessVars.GetNetworkFactor(nil) * width
+	networkCost := outCount * sessVars.GetNetworkFactor(impl.tblInfo) * width
 	// copTasks are run in parallel, to make the estimated cost closer to execution time, we amortize
 	// the cost to cop iterator workers. According to `CopClient::Send`, the concurrency
 	// is Min(DistSQLScanConcurrency, numRegionsInvolvedInScan), since we cannot infer
@@ -130,6 +133,7 @@ func (impl *TableScanImpl) CalcCost(outCount float64, children ...memo.Implement
 // IndexReaderImpl is the implementation of PhysicalIndexReader.
 type IndexReaderImpl struct {
 	baseImpl
+	tblInfo     *model.TableInfo
 	tblColHists *statistics.HistColl
 }
 
@@ -148,17 +152,18 @@ func (impl *IndexReaderImpl) GetCostLimit(costLimit float64, children ...memo.Im
 func (impl *IndexReaderImpl) CalcCost(outCount float64, children ...memo.Implementation) float64 {
 	reader := impl.plan.(*plannercore.PhysicalIndexReader)
 	sessVars := reader.SCtx().GetSessionVars()
-	networkCost := outCount * sessVars.GetNetworkFactor(nil) * impl.tblColHists.GetAvgRowSize(reader.SCtx(), children[0].GetPlan().Schema().Columns, true, false)
+	networkCost := outCount * sessVars.GetNetworkFactor(impl.tblInfo) * impl.tblColHists.GetAvgRowSize(reader.SCtx(), children[0].GetPlan().Schema().Columns, true, false)
 	copIterWorkers := float64(sessVars.DistSQLScanConcurrency())
 	impl.cost = (networkCost + children[0].GetCost()) / copIterWorkers
 	return impl.cost
 }
 
 // NewIndexReaderImpl creates a new IndexReader Implementation.
-func NewIndexReaderImpl(reader *plannercore.PhysicalIndexReader, tblColHists *statistics.HistColl) *IndexReaderImpl {
+func NewIndexReaderImpl(reader *plannercore.PhysicalIndexReader, source *plannercore.DataSource) *IndexReaderImpl {
 	return &IndexReaderImpl{
 		baseImpl:    baseImpl{plan: reader},
-		tblColHists: tblColHists,
+		tblInfo:     source.TableInfo(),
+		tblColHists: source.TblColHists,
 	}
 }