Fix SeekToLatest memory leakage and remove redundant logic (#11057)

Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>

internal/util/rocksmq/server/rocksmq/rocksmq_impl.go

@@ -12,7 +12,6 @@
 package rocksmq
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"strconv"
@@ -723,30 +722,28 @@ func (rmq *rocksmq) SeekToLatest(topicName, groupName string) error {
 
 	fixChanName, _ := fixChannelName(topicName)
 	iter.Seek([]byte(fixChanName + "/"))
-	var last []byte
+	iKey := iter.Key()
 	// iter.SeekToLast bypass prefix limitation
-	// use for range until find next prefix for now
+	// use for range until iterator invalid for now
 	if iter.Valid() {
-		last = iter.Key().Data()
-		current := last
-		for bytes.HasPrefix(current, []byte(topicName)) {
+		iter.Next()
+		for iter.Valid() {
+			iKey.Free()
+			iKey = iter.Key()
 			iter.Next()
-			if iter.Valid() {
-				current = last
-				last = iter.Key().Data()
-			} else {
-				break
-			}
 		}
 	} else {
 		// In this case there are no messages, so shouldn't return error
 		return nil
 	}
-
-	if len(last) <= FixedChannelNameLen {
+	if iKey == nil {
 		return nil
 	}
-	msgID, err := strconv.ParseInt(string(last)[FixedChannelNameLen+1:], 10, 64)
+
+	seekMsgID := string(iKey.Data()) // bytes to string, copy
+	iKey.Free()
+
+	msgID, err := strconv.ParseInt(seekMsgID[FixedChannelNameLen+1:], 10, 64)
 	if err != nil {
 		return err
 	}