fix checkSegmentSize overflows int64 (#15858)

Signed-off-by: Nguyan <632722781@qq.com>

internal/querynode/segment_loader.go

@@ -623,7 +623,7 @@ func (loader *segmentLoader) checkSegmentSize(collectionID UniqueID, segmentLoad
 	}
 
 	// when load segment, data will be copied from go memory to c++ memory
-	if usedMemAfterLoad+maxSegmentSize > int64(float64(totalMem)*Params.QueryNodeCfg.OverloadedMemoryThresholdPercentage) {
+	if uint64(usedMemAfterLoad+maxSegmentSize) > uint64(float64(totalMem)*Params.QueryNodeCfg.OverloadedMemoryThresholdPercentage) {
 		return fmt.Errorf("load segment failed, OOM if load, collectionID = %d, maxSegmentSize = %d, usedMemAfterLoad = %d, totalMem = %d, thresholdFactor = %f",
 			collectionID, maxSegmentSize, usedMemAfterLoad, totalMem, Params.QueryNodeCfg.OverloadedMemoryThresholdPercentage)
 	}