delete unnecessary var

Signed-off-by: guo-shaoge <[email protected]>

planner/core/find_best_task.go

@@ -1988,8 +1988,7 @@ func (ds *DataSource) convertToTableScan(prop *property.PhysicalProperty, candid
 	}
 	// In disaggregated tiflash mode, only MPP is allowed, cop and batchCop is deprecated.
 	// So if prop.TaskTp is RootTaskType, have to use mppTask then convert to rootTask.
-	isDisaggregatedTiFlash := config.GetGlobalConfig().DisaggregatedTiFlash
-	isDisaggregatedTiFlashPath := isDisaggregatedTiFlash && ts.StoreType == kv.TiFlash
+	isDisaggregatedTiFlashPath := config.GetGlobalConfig().DisaggregatedTiFlash && ts.StoreType == kv.TiFlash
 	canMppConvertToRootForDisaggregatedTiFlash := isDisaggregatedTiFlashPath && prop.TaskTp == property.RootTaskType && ds.SCtx().GetSessionVars().IsMPPAllowed()
 	if prop.TaskTp == property.MppTaskType || canMppConvertToRootForDisaggregatedTiFlash {
 		if ts.KeepOrder {

planner/core/task.go

@@ -2068,7 +2068,6 @@ type mppTask struct {
 	partTp   property.MPPPartitionType
 	hashCols []*property.MPPPartitionColumn
 
-	tblColHists *statistics.HistColl
 	// rootTaskConds record filters of TableScan that cannot be pushed down to TiFlash.
 
 	// For logical plan like: HashAgg -> Selection -> TableScan, if filters in Selection cannot be pushed to TiFlash.
@@ -2080,6 +2079,7 @@ type mppTask struct {
 	// and filters in rootTaskConds will be added in a Selection which will be executed in TiDB.
 	// So physical plan be like: PhysicalHashAgg -> PhysicalSelection -> TableReader -> ExchangeSender -> PhysicalTableScan(mpp tiflash)
 	rootTaskConds []expression.Expression
+	tblColHists   *statistics.HistColl
 }
 
 func (t *mppTask) count() float64 {