puller/sorter: remove manual GC setttings

Signed-off-by: Neil Shen <overvenus@gmail.com>

cdc/puller/sorter/backend_pool.go

@@ -19,8 +19,6 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
-	"runtime"
-	"runtime/debug"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -133,18 +131,6 @@ func newBackEndPool(dir string, captureAddr string) (*backEndPool, error) {
 				atomic.StoreInt32(&ret.memPressure, int32(memPressure))
 			}
 
-			if memPressure := ret.memoryPressure(); memPressure > 50 {
-				log.Debug("unified sorter: high memory pressure", zap.Int32("memPressure", memPressure),
-					zap.Int64("usedBySorter", ret.sorterMemoryUsage()))
-				// Increase GC frequency to avoid unnecessary OOMs
-				debug.SetGCPercent(10)
-				if memPressure > 80 {
-					runtime.GC()
-				}
-			} else {
-				debug.SetGCPercent(50)
-			}
-
 			// garbage collect temporary files in batches
 			freedCount := 0
 			for i := range ret.cache {