diff --git a/Cargo.toml b/Cargo.toml
index e3b97b3..bab01a3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kip_db"
-version = "0.1.2-alpha.14"
+version = "0.1.2-alpha.15"
 edition = "2021"
 authors = ["Kould <kould2333@gmail.com>"]
 description = "轻量级、异步 基于LSM Leveled Compaction K-V数据库"
diff --git a/src/kernel/lsm/mvcc.rs b/src/kernel/lsm/mvcc.rs
index 9dbe584..dd8a40e 100644
--- a/src/kernel/lsm/mvcc.rs
+++ b/src/kernel/lsm/mvcc.rs
@@ -19,8 +19,10 @@ use std::sync::Arc;
 use tokio::sync::mpsc::error::TrySendError;
 use tokio::sync::mpsc::Sender;
 
-type MapIter<'a> =
-    Map<skiplist::skipmap::Iter<'a, Bytes, KeyValue>, fn((&Bytes, &KeyValue)) -> KeyValue>;
+type MapIter<'a> = Map<
+    skiplist::skipmap::Iter<'a, Bytes, Option<Bytes>>,
+    fn((&Bytes, &Option<Bytes>)) -> KeyValue,
+>;
 
 unsafe impl Send for BufPtr {}
 unsafe impl Sync for BufPtr {}
@@ -32,7 +34,7 @@ pub struct Transaction {
     pub(crate) compactor_tx: Sender<CompactTask>,
 
     pub(crate) version: Arc<Version>,
-    pub(crate) writer_buf: SkipMap<Bytes, KeyValue>,
+    pub(crate) writer_buf: SkipMap<Bytes, Option<Bytes>>,
     pub(crate) seq_id: i64,
 }
 
@@ -42,7 +44,7 @@ impl Transaction {
     /// 此处不需要等待压缩，因为在Transaction存活时不会触发Compaction
     #[inline]
     pub fn get(&self, key: &[u8]) -> Result<Option<Bytes>> {
-        if let Some((_, value)) = self.writer_buf.get(key) {
+        if let Some(value) = self.writer_buf.get(key) {
             return Ok(value.clone());
         }
 
@@ -58,18 +60,15 @@ impl Transaction {
     }
 
     #[inline]
-    pub fn set(&mut self, key: &[u8], value: Bytes) {
-        let bytes = Bytes::copy_from_slice(key);
-
-        let _ignore = self.writer_buf.insert(bytes.clone(), (bytes, Some(value)));
+    pub fn set(&mut self, key: Bytes, value: Bytes) {
+        let _ignore = self.writer_buf.insert(key, Some(value));
     }
 
     #[inline]
     pub fn remove(&mut self, key: &[u8]) -> Result<()> {
         let _ = self.get(key)?.ok_or(KernelError::KeyNotFound)?;
-
         let bytes = Bytes::copy_from_slice(key);
-        let _ignore = self.writer_buf.insert(bytes.clone(), (bytes, None));
+        let _ignore = self.writer_buf.insert(bytes, None);
 
         Ok(())
     }
@@ -80,7 +79,7 @@ impl Transaction {
         let batch_data = self
             .writer_buf
             .iter()
-            .map(|(_, item)| item.clone())
+            .map(|(key, value)| (key.clone(), value.clone()))
             .collect_vec();
 
         if mem_table.insert_batch_data(batch_data, Sequence::create())? {
@@ -111,7 +110,7 @@ impl Transaction {
                 min.map(Bytes::copy_from_slice).as_ref(),
                 max.map(Bytes::copy_from_slice).as_ref(),
             )
-            .map(|(_, value)| (value.clone()))
+            .map(|(key, value)| (key.clone(), value.clone()))
     }
 
     fn mem_table(&self) -> &MemTable {