diff --git a/af/tmq/consumer.go b/af/tmq/consumer.go
index aab447c..ddc2e0a 100644
--- a/af/tmq/consumer.go
+++ b/af/tmq/consumer.go
@@ -65,12 +65,12 @@ func (c *Consumer) SubscribeTopics(topics []string, rebalanceCb RebalanceCb) err
 	for _, topic := range topics {
 		errCode := wrapper.TMQListAppend(topicList, topic)
 		if errCode != 0 {
-			return c.tmqError(errCode)
+			return tmqError(errCode)
 		}
 	}
 	errCode := wrapper.TMQSubscribe(c.cConsumer, topicList)
 	if errCode != 0 {
-		return c.tmqError(errCode)
+		return tmqError(errCode)
 	}
 	return nil
 }
@@ -79,7 +79,7 @@ func (c *Consumer) SubscribeTopics(topics []string, rebalanceCb RebalanceCb) err
 func (c *Consumer) Unsubscribe() error {
 	errCode := wrapper.TMQUnsubscribe(c.cConsumer)
 	if errCode != taosError.SUCCESS {
-		return c.tmqError(errCode)
+		return tmqError(errCode)
 	}
 	return nil
 }
@@ -199,7 +199,7 @@ func (c *Consumer) getData(message unsafe.Pointer) ([]*tmq.Data, error) {
 func (c *Consumer) Commit() ([]tmq.TopicPartition, error) {
 	errCode := wrapper.TMQCommitSync(c.cConsumer, nil)
 	if errCode != taosError.SUCCESS {
-		return nil, c.tmqError(errCode)
+		return nil, tmqError(errCode)
 	}
 	partitions, err := c.Assignment()
 	if err != nil {
@@ -208,18 +208,10 @@ func (c *Consumer) Commit() ([]tmq.TopicPartition, error) {
 	return c.Committed(partitions, 0)
 }
 
-func (c *Consumer) doCommit(message unsafe.Pointer) ([]tmq.TopicPartition, error) {
-	errCode := wrapper.TMQCommitSync(c.cConsumer, message)
-	if errCode != taosError.SUCCESS {
-		return nil, c.tmqError(errCode)
-	}
-	return nil, nil
-}
-
 func (c *Consumer) Assignment() (partitions []tmq.TopicPartition, err error) {
 	errCode, list := wrapper.TMQSubscription(c.cConsumer)
 	if errCode != taosError.SUCCESS {
-		return nil, c.tmqError(errCode)
+		return nil, tmqError(errCode)
 	}
 	defer wrapper.TMQListDestroy(list)
 	size := wrapper.TMQListGetSize(list)
@@ -227,7 +219,7 @@ func (c *Consumer) Assignment() (partitions []tmq.TopicPartition, err error) {
 	for _, topic := range topics {
 		errCode, assignment := wrapper.TMQGetTopicAssignment(c.cConsumer, topic)
 		if errCode != taosError.SUCCESS {
-			return nil, c.tmqError(errCode)
+			return nil, tmqError(errCode)
 		}
 		for i := 0; i < len(assignment); i++ {
 			topicName := topic
@@ -244,7 +236,7 @@ func (c *Consumer) Assignment() (partitions []tmq.TopicPartition, err error) {
 func (c *Consumer) Seek(partition tmq.TopicPartition, ignoredTimeoutMs int) error {
 	errCode := wrapper.TMQOffsetSeek(c.cConsumer, *partition.Topic, partition.Partition, int64(partition.Offset))
 	if errCode != taosError.SUCCESS {
-		return c.tmqError(errCode)
+		return tmqError(errCode)
 	}
 	return nil
 }
@@ -255,7 +247,7 @@ func (c *Consumer) Committed(partitions []tmq.TopicPartition, timeoutMs int) (of
 		cOffset := wrapper.TMQCommitted(c.cConsumer, *partitions[i].Topic, partitions[i].Partition)
 		offset := tmq.Offset(cOffset)
 		if !offset.Valid() {
-			return nil, c.tmqError(int32(offset))
+			return nil, tmqError(int32(offset))
 		}
 		offsets[i] = tmq.TopicPartition{
 			Topic:     partitions[i].Topic,
@@ -270,7 +262,7 @@ func (c *Consumer) CommitOffsets(offsets []tmq.TopicPartition) ([]tmq.TopicParti
 	for i := 0; i < len(offsets); i++ {
 		errCode := wrapper.TMQCommitOffsetSync(c.cConsumer, *offsets[i].Topic, offsets[i].Partition, int64(offsets[i].Offset))
 		if errCode != taosError.SUCCESS {
-			return nil, c.tmqError(errCode)
+			return nil, tmqError(errCode)
 		}
 	}
 	return c.Committed(offsets, 0)
@@ -281,7 +273,7 @@ func (c *Consumer) Position(partitions []tmq.TopicPartition) (offsets []tmq.Topi
 	for i := 0; i < len(partitions); i++ {
 		position := wrapper.TMQPosition(c.cConsumer, *partitions[i].Topic, partitions[i].Partition)
 		if position < 0 {
-			return nil, c.tmqError(int32(position))
+			return nil, tmqError(int32(position))
 		}
 		offsets[i] = tmq.TopicPartition{
 			Topic:     partitions[i].Topic,
@@ -296,12 +288,12 @@ func (c *Consumer) Position(partitions []tmq.TopicPartition) (offsets []tmq.Topi
 func (c *Consumer) Close() error {
 	errCode := wrapper.TMQConsumerClose(c.cConsumer)
 	if errCode != 0 {
-		return c.tmqError(errCode)
+		return tmqError(errCode)
 	}
 	return nil
 }
 
-func (c *Consumer) tmqError(errCode int32) error {
+func tmqError(errCode int32) error {
 	errStr := wrapper.TMQErr2Str(errCode)
 	return taosError.NewError(int(errCode), errStr)
 }
diff --git a/af/tmq/consumer_test.go b/af/tmq/consumer_test.go
index 47252b7..ebee650 100644
--- a/af/tmq/consumer_test.go
+++ b/af/tmq/consumer_test.go
@@ -493,3 +493,9 @@ func TestMeta(t *testing.T) {
 		}
 	}
 }
+
+func Test_tmqError(t *testing.T) {
+	err := tmqError(-1)
+	expectError := &errors.TaosError{Code: 65535, ErrStr: "fail"}
+	assert.Equal(t, expectError, err)
+}