diff --git a/docs/config.md b/docs/config.md
index 71ffa8c6..d3a6917c 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -80,17 +80,17 @@ The default configuration file is /etc/vflow/mq.conf, you can be able to change
 ## Configuration Keys
 The Kafka configuration contains the following key
 
-|Key                  | Default     |  Environment variable    | Description                                                                        |
-|---------------------| ------------|--------------------------|------------------------------------------------------------------------------------|
-|brokers              | -           | VFLOW_KAFKA_BROKERS      | kafka broker addresses                                                             |
-|compression          | none        | VFLOW_KAFKA_COMPRESSION  | compression codecs: gzip, snappy, lz4                                              |
-|retry-max            | 2           | VFLOW_KAFKA_RETRY_MAX    | the total number of times to retry                                                 |
-|request-size-max     | 104857600   | NA                       | the maximum size (in bytes) of any request that will be attempted to send to Kafka |
-|retry-backoff        | 10          | VFLOW_KAFKA_RETRY_BACKOFF| wait for leader election to occur before retrying in milliseconds                  |
-|tls-cert             | none        | VFLOW_KAFKA_TLS_CERT     | certificate file for client authentication                                         |
-|tls-key              | none        | VFLOW_KAFKA_TLS_KEY      | key file for client authentication                                                 |
-|ca-file              | none        | VFLOW_KAFKA_CA_FILE      | certificate authority file for TLS client authentication                           |
-|verify-ssl           | true        | VFLOW_KAFKA_VERIFY_SSL   | verify ssl certificates chain                                                      |
+|Key                  | Default     |  Environment variable        | Description                                                                        |
+|---------------------| ------------|------------------------------|------------------------------------------------------------------------------------|
+|brokers              | -           | VFLOW_KAFKA_BROKERS          | kafka broker addresses                                                             |
+|compression          | none        | VFLOW_KAFKA_COMPRESSION      | compression codecs: gzip, snappy, lz4                                              |
+|retry-max            | 2           | VFLOW_KAFKA_RETRY_MAX        | the total number of times to retry                                                 |
+|request-size-max     | 104857600   | VFLOW_KAFKA_REQUEST_SIZE_MAX | the maximum size (in bytes) of any request that will be attempted to send to Kafka |
+|retry-backoff        | 10          | VFLOW_KAFKA_RETRY_BACKOFF    | wait for leader election to occur before retrying in milliseconds                  |
+|tls-cert             | none        | VFLOW_KAFKA_TLS_CERT         | certificate file for client authentication                                         |
+|tls-key              | none        | VFLOW_KAFKA_TLS_KEY          | key file for client authentication                                                 |
+|ca-file              | none        | VFLOW_KAFKA_CA_FILE          | certificate authority file for TLS client authentication                           |
+|verify-ssl           | true        | VFLOW_KAFKA_VERIFY_SSL       | verify ssl certificates chain                                                      |
 
 ## Example
 ```
diff --git a/producer/kafka.go b/producer/kafka.go
index 68992038..ce0dc447 100644
--- a/producer/kafka.go
+++ b/producer/kafka.go
@@ -49,7 +49,7 @@ type KafkaConfig struct {
 	Brokers        []string `yaml:"brokers" env:"BROKERS"`
 	Compression    string   `yaml:"compression" env:"COMPRESSION"`
 	RetryMax       int      `yaml:"retry-max" env:"RETRY_MAX"`
-	RequestSizeMax int32    `yaml:"request-size-max" env:"NA"`
+	RequestSizeMax int32    `yaml:"request-size-max" env:"REQUEST_SIZE_MAX"`
 	RetryBackoff   int      `yaml:"retry-backoff" env:"RETRY_BACKOFF"`
 	TLSCertFile    string   `yaml:"tls-cert" env:"TLS_CERT"`
 	TLSKeyFile     string   `yaml:"tls-key" env:"TLS_KEY"`