diff --git a/core/src/main/scala/kafka/log/Log.scala b/core/src/main/scala/kafka/log/Log.scala
index b2a7170..b7e3826 100644
--- a/core/src/main/scala/kafka/log/Log.scala
+++ b/core/src/main/scala/kafka/log/Log.scala
@@ -260,7 +260,8 @@ private[kafka] class Log(val dir: File,
    */
   def append(messages: ByteBufferMessageSet, assignOffsets: Boolean = true): (Long, Long) = {
     val messageSetInfo = analyzeAndValidateMessageSet(messages)
-    
+    val firstOffset = nextOffset.get
+
     // if we have any valid messages, append them to the log
     if(messageSetInfo.count == 0) {
       (-1L, -1L)
@@ -318,7 +319,8 @@ private[kafka] class Log(val dir: File,
         }
         
         // maybe flush the log and index
-        maybeFlush(messageSetInfo.count)
+        val numAppendedMessages = (nextOffset.get - firstOffset).toInt
+        maybeFlush(numAppendedMessages)
         
         // return the first and last offset
         offsets
diff --git a/core/src/main/scala/kafka/server/KafkaConfig.scala b/core/src/main/scala/kafka/server/KafkaConfig.scala
index b8970c8..549b4b0 100644
--- a/core/src/main/scala/kafka/server/KafkaConfig.scala
+++ b/core/src/main/scala/kafka/server/KafkaConfig.scala
@@ -110,7 +110,7 @@ class KafkaConfig private (val props: VerifiableProperties) extends ZKConfig(pro
   val logIndexIntervalBytes = props.getIntInRange("log.index.interval.bytes", 4096, (0, Int.MaxValue))
 
   /* the number of messages accumulated on a log partition before messages are flushed to disk */
-  val logFlushIntervalMessages = props.getIntInRange("log.flush.interval.messages", 500, (1, Int.MaxValue))
+  val logFlushIntervalMessages = props.getIntInRange("log.flush.interval.messages", 10000, (1, Int.MaxValue))
 
   /* the maximum time in ms that a message in selected topics is kept in memory before flushed to disk, e.g., topic1:3000,topic2: 6000  */
   val logFlushIntervalMsPerTopicMap = props.getMap("log.flush.interval.ms.per.topic", _.toInt > 0).mapValues(_.toInt)