[KAFKA-3840] OS auto tuning for socket buffer size in clients not allowed through configuration

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.10.1.0
• Flags: Patch
• Assignee: Unassigned
• Reporter: Sébastien Launay
• Created: 14/Jun/16 22:27
• Updated: 16/Jun/16 12:39
• Resolved: 16/Jun/16 12:39

Description

KAFKA-724 added the following documentation for clients in order to provide OS auto tuning of socket buffer sizes:

diff --git a/clients/src/main/java/org/apache/kafka/clients/CommonClientConfigs.java b/clients/src/main/java/org/apache/kafka/clients/CommonClientConfigs.java
index 750b8a1..3327815 100644
--- a/clients/src/main/java/org/apache/kafka/clients/CommonClientConfigs.java
+++ b/clients/src/main/java/org/apache/kafka/clients/CommonClientConfigs.java
@@ -43,10 +43,10 @@
     public static final String METADATA_MAX_AGE_DOC = "The period of time in milliseconds after which we force a refresh of metadata even if we haven't seen any partition leadership changes to proactively discover any new brokers or partitions.";
 
     public static final String SEND_BUFFER_CONFIG = "send.buffer.bytes";
-    public static final String SEND_BUFFER_DOC = "The size of the TCP send buffer (SO_SNDBUF) to use when sending data.";
+    public static final String SEND_BUFFER_DOC = "The size of the TCP send buffer (SO_SNDBUF) to use when sending data. If the value is -1, the OS default will be used.";
 
     public static final String RECEIVE_BUFFER_CONFIG = "receive.buffer.bytes";
-    public static final String RECEIVE_BUFFER_DOC = "The size of the TCP receive buffer (SO_RCVBUF) to use when reading data.";
+    public static final String RECEIVE_BUFFER_DOC = "The size of the TCP receive buffer (SO_RCVBUF) to use when reading data. If the value is -1, the OS default will be used.";
 
     public static final String CLIENT_ID_CONFIG = "client.id";
     public static final String CLIENT_ID_DOC = "An id string to pass to the server when making requests. The purpose of this is to be able to track the source of requests beyond just ip/port by allowing a logical application name to be included in server-side request logging.";

Unfortunately, the value -1 is not allowed for clients configuration and the following exception is thrown:

Exception in thread "main" org.apache.kafka.common.config.ConfigException: Invalid value -1 for configuration receive.buffer.bytes: Value must be at least 0
    at org.apache.kafka.common.config.ConfigDef$Range.ensureValid(ConfigDef.java:308)
    at org.apache.kafka.common.config.ConfigDef.parse(ConfigDef.java:153)
    at org.apache.kafka.common.config.AbstractConfig.<init>(AbstractConfig.java:49)
    at org.apache.kafka.common.config.AbstractConfig.<init>(AbstractConfig.java:56)
    at org.apache.kafka.clients.producer.ProducerConfig.<init>(ProducerConfig.java:315)
    at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:156)
    ...

This is caused by an atLeast(0) validation in ProducerConfig.java and ConsumerConfig.java::

...
  .define(SEND_BUFFER_CONFIG, Type.INT, 128 * 1024, atLeast(0), Importance.MEDIUM, CommonClientConfigs.SEND_BUFFER_DOC)
  .define(RECEIVE_BUFFER_CONFIG, Type.INT, 32 * 1024, atLeast(0), Importance.MEDIUM, CommonClientConfigs.RECEIVE_BUFFER_DOC)
...

Note that the broker configuration for OS auto tuning is fine as there is no such checks in KafkaConfig.scala.

Issue Links

• links to: GitHub Pull Request #1507