remove unnessary drains in eviction (#10559)

Author: luluz66

enterprise/server/backends/pebble_cache/pebble_cache.go

@@ -2625,10 +2625,6 @@ func newPartitionEvictor(ctx context.Context, part disk.Partition, fileStorer fi
 
 func (e *partitionEvictor) startSampleGenerator(quitChan chan struct{}) {
 	e.generateSamplesForEviction(quitChan)
-	// Drain samples chan before exiting
-	for len(e.samples) > 0 {
-		<-e.samples
-	}
 	close(e.samples)
 }
 
@@ -2647,9 +2643,6 @@ func (e *partitionEvictor) processEviction(quitChan chan struct{}) {
 		})
 	}
 	eg.Wait()
-	for len(e.deletes) > 0 {
-		<-e.deletes
-	}
 }
 
 func (e *partitionEvictor) generateSamplesForEviction(quitChan chan struct{}) error {

enterprise/server/raft/usagetracker/usagetracker.go

@@ -264,9 +264,6 @@ func (pu *partitionUsage) processEviction(ctx context.Context) {
 	for {
 		select {
 		case <-ctx.Done():
-			for len(pu.deletes) > 0 {
-				<-pu.deletes
-			}
 			return
 		case sampleToDelete := <-pu.deletes:
 			keys = append(keys, &sender.KeyMeta{
@@ -284,10 +281,6 @@ func (pu *partitionUsage) processEviction(ctx context.Context) {
 
 func (pu *partitionUsage) startSampleGenerator(ctx context.Context) {
 	pu.generateSamplesForEviction(ctx)
-	// Drain samples chan before exiting
-	for len(pu.samples) > 0 {
-		<-pu.samples
-	}
 	close(pu.samples)
 }