diff --git a/pulsar-broker/src/main/java/org/apache/pulsar/client/impl/RawBatchConverter.java b/pulsar-broker/src/main/java/org/apache/pulsar/client/impl/RawBatchConverter.java
index 64ddea3ec6ab1..8ef76f64b0842 100644
--- a/pulsar-broker/src/main/java/org/apache/pulsar/client/impl/RawBatchConverter.java
+++ b/pulsar-broker/src/main/java/org/apache/pulsar/client/impl/RawBatchConverter.java
@@ -142,12 +142,12 @@ public static Optional<RawMessage> rebatchMessage(RawMessage msg,
         } else {
             Commands.skipMessageMetadata(payload);
         }
-        ByteBuf batchBuffer = PulsarByteBufAllocator.DEFAULT.buffer(payload.capacity());
+        int uncompressedSize = metadata.getUncompressedSize();
+        ByteBuf batchBuffer = PulsarByteBufAllocator.DEFAULT.buffer(uncompressedSize);
 
         CompressionType compressionType = metadata.getCompression();
         CompressionCodec codec = CompressionCodecProvider.getCompressionCodec(compressionType);
 
-        int uncompressedSize = metadata.getUncompressedSize();
         ByteBuf uncompressedPayload = codec.decode(payload, uncompressedSize);
         try {
             int batchSize = metadata.getNumMessagesInBatch();