diff --git a/dbms/include/DB/IO/CompressedWriteBuffer.h b/dbms/include/DB/IO/CompressedWriteBuffer.h
index 05fe15a01fa..552ff5e0ce8 100644
--- a/dbms/include/DB/IO/CompressedWriteBuffer.h
+++ b/dbms/include/DB/IO/CompressedWriteBuffer.h
@@ -26,6 +26,9 @@ private:
 
 	void nextImpl()
 	{
+		if (!offset())
+			return;
+
 		size_t uncompressed_size = offset();
 		compressed_buffer.resize(uncompressed_size + QUICKLZ_ADDITIONAL_SPACE);
 
diff --git a/dbms/include/DB/IO/WriteBufferFromOStream.h b/dbms/include/DB/IO/WriteBufferFromOStream.h
index 125149d4aa5..d1a30150b14 100644
--- a/dbms/include/DB/IO/WriteBufferFromOStream.h
+++ b/dbms/include/DB/IO/WriteBufferFromOStream.h
@@ -20,6 +20,9 @@ private:
 
 	void nextImpl()
 	{
+		if (!offset())
+			return;
+		
 		ostr.write(working_buffer.begin(), offset());
 		ostr.flush();