Force reclamation of memory after loading (#17244)

Signed-off-by: xige-16 <xi.ge@zilliz.com>

internal/querynode/segment_loader.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"path"
 	"runtime"
+	"runtime/debug"
 	"strconv"
 	"sync"
 
@@ -141,6 +142,7 @@ func (loader *segmentLoader) loadSegment(req *querypb.LoadSegmentsRequest, segme
 		for _, s := range newSegments {
 			deleteSegment(s)
 		}
+		debug.FreeOSMemory()
 	}
 
 	for _, info := range req.Infos {
@@ -235,6 +237,10 @@ func (loader *segmentLoader) loadSegmentInternal(segment *Segment,
 		return err
 	}
 
+	// TODO(xige-16): Optimize the data loading process and reduce data copying
+	// for now, there will be multiple copies in the process of data loading into segCore
+	defer debug.FreeOSMemory()
+
 	var fieldBinlogs []*datapb.FieldBinlog
 	if segment.getType() == segmentTypeSealed {
 		fieldID2IndexInfo := make(map[int64]*querypb.FieldIndexInfo)