pref: optimize the structure of write buf to avoid frequent copying o…

…f keys

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 <[email protected]>"]
 description = "轻量级、异步 基于LSM Leveled Compaction K-V数据库"

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 {