small improve

pingcap · Mar 9, 2023 · c45f116 · c45f116
1 parent d72bab7
commit c45f116
Show file tree

Hide file tree

Showing 5 changed files with 15 additions and 10 deletions.
diff --git a/distsql/select_result.go b/distsql/select_result.go
@@ -153,16 +153,16 @@ func (ssr *sortedSelectResults) Next(ctx context.Context, c *chunk.Chunk) (err e
 	for c.NumRows() < c.RequiredRows() {
 		minSelectResultIdx := -1
 		for i := range ssr.cachedChunks {
-			if ssr.cachedChunkIdx[i] >= ssr.cachedChunks[i].NumRows() {
+			if ssr.cachedChunkIdx[i] == ssr.cachedChunks[i].NumRows() {
 				prevMemUsage := ssr.cachedChunks[i].MemoryUsage()
 				if err = ssr.selectResult[i].Next(ctx, ssr.cachedChunks[i]); err != nil {
 					return err
 				}
+				ssr.cachedChunkIdx[i] = 0
+				ssr.memTracker.Consume(ssr.cachedChunks[i].MemoryUsage() - prevMemUsage)
 				if ssr.cachedChunks[i].NumRows() == 0 {
 					continue
 				}
-				ssr.cachedChunkIdx[i] = 0
-				ssr.memTracker.Consume(ssr.cachedChunks[i].MemoryUsage() - prevMemUsage)
 			}
 			idx := ssr.cachedChunkIdx[i]
 			row := ssr.cachedChunks[i].GetRow(idx)

diff --git a/executor/distsql.go b/executor/distsql.go
@@ -194,7 +194,8 @@ type IndexReaderExecutor struct {
 
 	keepOrder bool
 	desc      bool
-	byItems   []*plannerutil.ByItems
+	// byItems only for partition table with orderBy + pushedLimit
+	byItems []*plannerutil.ByItems
 
 	corColInFilter bool
 	corColInAccess bool

diff --git a/executor/table_reader.go b/executor/table_reader.go
@@ -106,6 +106,7 @@ type TableReaderExecutor struct {
 
 	keepOrder bool
 	desc      bool
+	// byItems only for partition table with orderBy + pushedLimit
 	byItems   []*util.ByItems
 	paging    bool
 	storeType kv.StoreType

diff --git a/planner/core/physical_plans.go b/planner/core/physical_plans.go
@@ -670,7 +670,9 @@ type PhysicalIndexScan struct {
 	isPartition bool
 	Desc        bool
 	KeepOrder   bool
-	ByItems     []*util.ByItems
+	// ByItems only for partition table with orderBy + pushedLimit
+	ByItems []*util.ByItems
+
 	// DoubleRead means if the index executor will read kv two times.
 	// If the query requires the columns that don't belong to index, DoubleRead will be true.
 	DoubleRead bool
@@ -826,7 +828,7 @@ type PhysicalTableScan struct {
 	// KeepOrder is true, if sort data by scanning pkcol,
 	KeepOrder bool
 	Desc      bool
-	// ByItems only for partition table with pushed limit
+	// ByItems only for partition table with orderBy + pushedLimit
 	ByItems []*util.ByItems
 
 	isChildOfIndexLookUp bool

diff --git a/planner/core/task.go b/planner/core/task.go
@@ -1233,13 +1233,14 @@ func (p *PhysicalTopN) pushPartialTopNDownToCop(copTsk *copTask) (task, bool) {
 			}
 
 			rootTask := copTsk.convertToRootTask(p.ctx)
-			if _, ok := rootTask.p.(*PhysicalIndexLookUpReader); !ok {
+			// only support IndexReader now.
+			if _, ok := rootTask.p.(*PhysicalIndexReader); ok {
 				rootLimit := PhysicalLimit{
 					Count:       p.Count,
 					Offset:      p.Offset,
 					PartitionBy: newPartitionBy,
 				}.Init(p.SCtx(), stats, p.SelectBlockOffset())
-				rootLimit.SetSchema(copTsk.indexPlan.Schema())
+				rootLimit.SetSchema(rootTask.plan().Schema())
 				return attachPlan2Task(rootLimit, rootTask), true
 			}
 		}
@@ -1285,13 +1286,13 @@ func (p *PhysicalTopN) pushPartialTopNDownToCop(copTsk *copTask) (task, bool) {
 			tblScan.SetStats(tblScan.Stats().ScaleByExpectCnt(scaledRowCount))
 		}
 
+		rootTask := copTsk.convertToRootTask(p.ctx)
 		rootLimit := PhysicalLimit{
 			Count:       p.Count,
 			Offset:      p.Offset,
 			PartitionBy: newPartitionBy,
 		}.Init(p.SCtx(), stats, p.SelectBlockOffset())
-		rootLimit.SetSchema(copTsk.tablePlan.Schema())
-		rootTask := copTsk.convertToRootTask(p.ctx)
+		rootLimit.SetSchema(rootTask.plan().Schema())
 		return attachPlan2Task(rootLimit, rootTask), true
 	} else {
 		return nil, false