diff --git a/diskqueue.go b/diskqueue.go
index 29d15ac..a9be6b7 100644
--- a/diskqueue.go
+++ b/diskqueue.go
@@ -70,6 +70,7 @@ type diskQueue struct {
 	name            string
 	dataPath        string
 	maxBytesPerFile int64 // currently this cannot change once created
+	curReadFileSize int64 // currently read file total filesize
 	minMsgSize      int32
 	maxMsgSize      int32
 	syncEvery       int64         // number of writes per fsync
@@ -293,6 +294,19 @@ func (d *diskQueue) readOne() ([]byte, error) {
 			}
 		}
 
+		if d.readFileNum < d.writeFileNum {
+			stat, err := d.readFile.Stat()
+			if err != nil {
+				// avoid get fileInfo error, use maxBytesPerFile do backup
+				d.curReadFileSize = d.maxBytesPerFile
+			} else {
+				d.curReadFileSize = stat.Size()
+			}
+		} else {
+			// when readFileNum equal writeFileNum before write file sync and close, use maxBytesPerFile instead of exact filesize
+			d.curReadFileSize = d.maxBytesPerFile
+		}
+
 		d.reader = bufio.NewReader(d.readFile)
 	}
 
@@ -326,10 +340,10 @@ func (d *diskQueue) readOne() ([]byte, error) {
 	d.nextReadPos = d.readPos + totalBytes
 	d.nextReadFileNum = d.readFileNum
 
-	// TODO: each data file should embed the maxBytesPerFile
-	// as the first 8 bytes (at creation time) ensuring that
+	// use the read file exact size, ensuring that
 	// the value can change without affecting runtime
-	if d.nextReadPos > d.maxBytesPerFile {
+	// only readFileNum less than writeFileNum need move next file
+	if d.readFileNum < d.writeFileNum && d.nextReadPos >= d.curReadFileSize {
 		if d.readFile != nil {
 			d.readFile.Close()
 			d.readFile = nil
@@ -396,6 +410,11 @@ func (d *diskQueue) writeOne(data []byte) error {
 	d.depth += 1
 
 	if d.writePos >= d.maxBytesPerFile {
+		// when readFileNum equal writeFileNum, before sync and close writefile should update curReadFileSize
+		if d.readFileNum == d.writeFileNum {
+			d.curReadFileSize = d.writePos
+		}
+
 		d.writeFileNum++
 		d.writePos = 0