planner: fix wrong task types when calculating cost in some cases (#4…

…3637) ref #35240
pingcap · May 9, 2023 · a7299d3 · a7299d3
1 parent 03ea3c1
commit a7299d3
Show file tree

Hide file tree

Showing 4 changed files with 34 additions and 14 deletions.
diff --git a/planner/core/casetest/testdata/enforce_mpp_suite_out.json b/planner/core/casetest/testdata/enforce_mpp_suite_out.json
@@ -51,10 +51,11 @@
       {
         "SQL": "explain format='verbose' select /*+ read_from_storage(tiflash[t]) */ count(*) from t where a=1",
         "Plan": [
-          "StreamAgg_10 1.00 64007.91 root  funcs:count(1)->Column#4",
-          "└─TableReader_24 10.00 63508.91 root  data:Selection_23",
-          "  └─Selection_23 10.00 952000.00 cop[tiflash]  eq(test.t.a, 1)",
-          "    └─TableFullScan_22 10000.00 928000.00 cop[tiflash] table:t pushed down filter:empty, keep order:false, stats:pseudo"
+          "StreamAgg_20 1.00 63520.28 root  funcs:count(Column#6)->Column#4",
+          "└─TableReader_21 1.00 63470.38 root  data:StreamAgg_9",
+          "  └─StreamAgg_9 1.00 952024.00 batchCop[tiflash]  funcs:count(1)->Column#6",
+          "    └─Selection_19 10.00 952000.00 batchCop[tiflash]  eq(test.t.a, 1)",
+          "      └─TableFullScan_18 10000.00 928000.00 batchCop[tiflash] table:t pushed down filter:empty, keep order:false, stats:pseudo"
         ],
         "Warn": null
       },
@@ -91,10 +92,11 @@
       {
         "SQL": "explain format='verbose' select /*+ read_from_storage(tiflash[t]) */ count(*) from t where a=1",
         "Plan": [
-          "StreamAgg_12 1.00 64007.91 root  funcs:count(1)->Column#4",
-          "└─TableReader_31 10.00 63508.91 root  data:Selection_30",
-          "  └─Selection_30 10.00 952000.00 cop[tiflash]  eq(test.t.a, 1)",
-          "    └─TableFullScan_29 10000.00 928000.00 cop[tiflash] table:t pushed down filter:empty, keep order:false, stats:pseudo"
+          "StreamAgg_27 1.00 63520.28 root  funcs:count(Column#7)->Column#4",
+          "└─TableReader_28 1.00 63470.38 root  data:StreamAgg_11",
+          "  └─StreamAgg_11 1.00 952024.00 batchCop[tiflash]  funcs:count(1)->Column#7",
+          "    └─Selection_26 10.00 952000.00 batchCop[tiflash]  eq(test.t.a, 1)",
+          "      └─TableFullScan_25 10000.00 928000.00 batchCop[tiflash] table:t pushed down filter:empty, keep order:false, stats:pseudo"
         ],
         "Warn": null
       },
@@ -126,10 +128,11 @@
       {
         "SQL": "explain format='verbose' select /*+ read_from_storage(tiflash[t]) */ count(*) from t where a=1",
         "Plan": [
-          "StreamAgg_12 1.00 64007.91 root  funcs:count(1)->Column#4",
-          "└─TableReader_31 10.00 63508.91 root  data:Selection_30",
-          "  └─Selection_30 10.00 952000.00 cop[tiflash]  eq(test.t.a, 1)",
-          "    └─TableFullScan_29 10000.00 928000.00 cop[tiflash] table:t pushed down filter:empty, keep order:false, stats:pseudo"
+          "StreamAgg_27 1.00 63520.28 root  funcs:count(Column#7)->Column#4",
+          "└─TableReader_28 1.00 63470.38 root  data:StreamAgg_11",
+          "  └─StreamAgg_11 1.00 952024.00 batchCop[tiflash]  funcs:count(1)->Column#7",
+          "    └─Selection_26 10.00 952000.00 batchCop[tiflash]  eq(test.t.a, 1)",
+          "      └─TableFullScan_25 10000.00 928000.00 batchCop[tiflash] table:t pushed down filter:empty, keep order:false, stats:pseudo"
         ],
         "Warn": null
       },
@@ -165,8 +168,8 @@
         "Plan": [
           "StreamAgg_27 1.00 49.90 root  funcs:count(Column#7)->Column#4",
           "└─TableReader_28 1.00 0.00 root  data:StreamAgg_11",
-          "  └─StreamAgg_11 1.00 1427024.00 batchCop[tiflash]  funcs:count(1)->Column#7",
-          "    └─Selection_26 10.00 1427000.00 batchCop[tiflash]  eq(test.t.a, 1)",
+          "  └─StreamAgg_11 1.00 952024.00 batchCop[tiflash]  funcs:count(1)->Column#7",
+          "    └─Selection_26 10.00 952000.00 batchCop[tiflash]  eq(test.t.a, 1)",
           "      └─TableFullScan_25 10000.00 928000.00 batchCop[tiflash] table:t pushed down filter:empty, keep order:false, stats:pseudo"
         ],
         "Warn": null

diff --git a/planner/core/find_best_task.go b/planner/core/find_best_task.go
@@ -323,6 +323,17 @@ func getTaskPlanCost(t task, op *physicalOptimizeOp) (float64, bool, error) {
 		taskType = property.RootTaskType
 	case *copTask: // no need to know whether the task is single-read or double-read, so both CopSingleReadTaskType and CopDoubleReadTaskType are OK
 		taskType = property.CopSingleReadTaskType
+
+		// TiFlash can run cop task as well, check whether this cop task will run on TiKV or TiFlash.
+		if t.(*copTask).tablePlan != nil {
+			leafNode := t.(*copTask).tablePlan
+			for len(leafNode.Children()) > 0 {
+				leafNode = leafNode.Children()[0]
+			}
+			if tblScan, isScan := leafNode.(*PhysicalTableScan); isScan && tblScan.StoreType == kv.TiFlash {
+				taskType = property.MppTaskType
+			}
+		}
 	case *mppTask:
 		taskType = property.MppTaskType
 	default:

diff --git a/planner/core/plan_cost_ver1.go b/planner/core/plan_cost_ver1.go
@@ -1270,6 +1270,9 @@ func getOperatorActRows(operator PhysicalPlan) float64 {
 func getCardinality(operator PhysicalPlan, costFlag uint64) float64 {
 	if hasCostFlag(costFlag, CostFlagUseTrueCardinality) {
 		actualProbeCnt := operator.getActualProbeCnt(operator.SCtx().GetSessionVars().StmtCtx.RuntimeStatsColl)
+		if actualProbeCnt == 0 {
+			return 0
+		}
 		return getOperatorActRows(operator) / float64(actualProbeCnt)
 	}
 	rows := operator.StatsCount()

diff --git a/planner/core/plan_cost_ver2.go b/planner/core/plan_cost_ver2.go
@@ -98,6 +98,9 @@ func (p *PhysicalProjection) getPlanCostVer2(taskType property.TaskType, option
 	inputRows := getCardinality(p.children[0], option.CostFlag)
 	cpuFactor := getTaskCPUFactorVer2(p, taskType)
 	concurrency := float64(p.ctx.GetSessionVars().ProjectionConcurrency())
+	if concurrency == 0 {
+		concurrency = 1 // un-parallel execution
+	}
 
 	projCost := filterCostVer2(option, inputRows, p.Exprs, cpuFactor)