planner: optimize performance of IndexUsage utilities

pkg/executor/executor.go

@@ -2036,7 +2036,14 @@ func ResetContextOfStmt(ctx sessionctx.Context, s ast.StmtNode) (err error) {
 		sc.RuntimeStatsColl = execdetails.NewRuntimeStatsColl(reuseObj)
 
 		// also enable index usage collector
-		sc.IndexUsageCollector = ctx.NewStmtIndexUsageCollector()
+		if sc.IndexUsageCollector == nil {
+			sc.IndexUsageCollector = ctx.NewStmtIndexUsageCollector()
+		} else {
+			sc.IndexUsageCollector.Reset()
+		}
+	} else {
+		// turn off the index usage collector
+		sc.IndexUsageCollector = nil
 	}
 
 	sc.SetForcePlanCache(fixcontrol.GetBoolWithDefault(vars.OptimizerFixControl, fixcontrol.Fix49736, false))

pkg/planner/core/stats.go

@@ -1084,7 +1084,16 @@ func loadTableStats(ctx sessionctx.Context, tblInfo *model.TableInfo, pid int64)
 
 	pctx := ctx.GetPlanCtx()
 	tableStats := getStatsTable(pctx, tblInfo, pid)
-	name, _ := getTblInfoForUsedStatsByPhysicalID(pctx, pid)
+
+	name := tblInfo.Name.O
+	partInfo := tblInfo.GetPartitionInfo()
+	if partInfo != nil {
+		for _, p := range partInfo.Definitions {
+			if p.ID == pid {
+				name += " " + p.Name.O
+			}
+		}
+	}
 	usedStats := &stmtctx.UsedStatsInfoForTable{
 		Name:          name,
 		TblInfo:       tblInfo,

pkg/statistics/handle/usage/indexusage/collector.go

@@ -88,6 +88,12 @@ func NewSample(queryTotal uint64, kvReqTotal uint64, rowAccess uint64, tableTota
 
 type indexUsage map[GlobalIndexID]Sample
 
+var indexUsagePool = sync.Pool{
+	New: func() any {
+		return make(indexUsage)
+	},
+}
+
 func (m indexUsage) updateByKey(id GlobalIndexID, sample Sample) {
 	item := m[id]
 	item.QueryTotal += sample.QueryTotal
@@ -127,7 +133,7 @@ type Collector struct {
 // NewCollector create an index usage collector
 func NewCollector() *Collector {
 	iuc := &Collector{
-		indexUsage: make(indexUsage),
+		indexUsage: indexUsagePool.Get().(indexUsage),
 	}
 	iuc.collector = collector.NewGlobalCollector[indexUsage](iuc.merge)
 
@@ -154,12 +160,16 @@ func (c *Collector) merge(delta indexUsage) {
 	defer c.Unlock()
 
 	c.indexUsage.merge(delta)
+
+	// return the `delta` to the pool
+	clear(delta)
+	indexUsagePool.Put(delta)
 }
 
 // SpawnSessionCollector creates a new session collector attached to this global collector
 func (c *Collector) SpawnSessionCollector() *SessionIndexUsageCollector {
 	return &SessionIndexUsageCollector{
-		indexUsage: make(indexUsage),
+		indexUsage: indexUsagePool.Get().(indexUsage),
 		collector:  c.collector.SpawnSession(),
 	}
 }
@@ -219,7 +229,7 @@ func (s *SessionIndexUsageCollector) Report() {
 		return
 	}
 	if s.collector.SendDelta(s.indexUsage) {
-		s.indexUsage = make(indexUsage)
+		s.indexUsage = indexUsagePool.Get().(indexUsage)
 	}
 }
 
@@ -230,7 +240,7 @@ func (s *SessionIndexUsageCollector) Flush() {
 		return
 	}
 	s.collector.SendDeltaSync(s.indexUsage)
-	s.indexUsage = make(indexUsage)
+	s.indexUsage = indexUsagePool.Get().(indexUsage)
 }
 
 // StmtIndexUsageCollector removes the duplicates index for recording `QueryTotal` in session collector
@@ -269,3 +279,11 @@ func (s *StmtIndexUsageCollector) Update(tableID int64, indexID int64, sample Sa
 
 	s.sessionCollector.Update(tableID, indexID, sample)
 }
+
+// Reset resets the recorded index in the collector to avoid re-allocating for each statement.
+func (s *StmtIndexUsageCollector) Reset() {
+	s.Lock()
+	defer s.Unlock()
+
+	clear(s.recordedIndex)
+}