KAFKA-1147 Consumer socket timeout should be greater than fetch max w…

…ait; reviewed by Neha Narkhede and Jun Rao

core/src/main/scala/kafka/consumer/ConsumerConfig.scala

@@ -102,8 +102,10 @@ class ConsumerConfig private (val props: VerifiableProperties) extends ZKConfig(
    *  Set this explicitly for only testing purpose. */
   val consumerId: Option[String] = Option(props.getString("consumer.id", null))
 
-  /** the socket timeout for network requests. The actual timeout set will be max.fetch.wait + socket.timeout.ms. */
+  /** the socket timeout for network requests. Its value should be at least fetch.wait.max.ms. */
   val socketTimeoutMs = props.getInt("socket.timeout.ms", SocketTimeout)
+  require(fetchWaitMaxMs <= socketTimeoutMs, "socket.timeout.ms should always be at least fetch.wait.max.ms" +
+    " to prevent unnecessary socket timeouts")
 
   /** the socket receive buffer for network requests */
   val socketReceiveBufferBytes = props.getInt("socket.receive.buffer.bytes", SocketBufferSize)

core/src/main/scala/kafka/server/KafkaConfig.scala

@@ -213,8 +213,10 @@ class KafkaConfig private (val props: VerifiableProperties) extends ZKConfig(pro
   /* If the lag in messages between a leader and a follower exceeds this number, the leader will remove the follower from isr */
   val replicaLagMaxMessages = props.getLong("replica.lag.max.messages", 4000)
 
-  /* the socket timeout for network requests */
+  /* the socket timeout for network requests. Its value should be at least replica.fetch.wait.max.ms. */
   val replicaSocketTimeoutMs = props.getInt("replica.socket.timeout.ms", ConsumerConfig.SocketTimeout)
+  require(replicaFetchWaitMaxMs <= replicaSocketTimeoutMs, "replica.socket.timeout.ms should always be at least replica.fetch.wait.max.ms" +
+    " to prevent unnecessary socket timeouts")
 
   /* the socket receive buffer for network requests */
   val replicaSocketReceiveBufferBytes = props.getInt("replica.socket.receive.buffer.bytes", ConsumerConfig.SocketBufferSize)