finish full tutorial

Signed-off-by: Alex Chi Z <iskyzh@gmail.com>

mini-lsm/src/lsm_storage.rs

@@ -148,6 +148,11 @@ fn key_within(user_key: &[u8], table_begin: KeySlice, table_end: KeySlice) -> bo
     table_begin.raw_ref() <= user_key && user_key <= table_end.raw_ref()
 }
 
+#[derive(Clone, Debug)]
+pub enum CompactionFilter {
+    Prefix(Bytes),
+}
+
 /// The storage interface of the LSM tree.
 pub(crate) struct LsmStorageInner {
     pub(crate) state: Arc<RwLock<Arc<LsmStorageState>>>,
@@ -160,6 +165,8 @@ pub(crate) struct LsmStorageInner {
     pub(crate) manifest: Option<Manifest>,
     #[allow(dead_code)]
     pub(crate) mvcc: Option<LsmMvccInner>,
+    #[allow(dead_code)]
+    pub(crate) compaction_filters: Arc<Mutex<Vec<CompactionFilter>>>,
 }
 
 /// A thin wrapper for `LsmStorageInner` and the user interface for MiniLSM.
@@ -243,6 +250,10 @@ impl MiniLsm {
         }))
     }
 
+    pub fn add_compaction_filter(&self, compaction_filter: CompactionFilter) {
+        self.inner.add_compaction_filter(compaction_filter)
+    }
+
     pub fn get(&self, key: &[u8]) -> Result<Option<Bytes>> {
         self.inner.get(key)
     }
@@ -418,6 +429,7 @@ impl LsmStorageInner {
             manifest: Some(manifest),
             options: options.into(),
             mvcc: None,
+            compaction_filters: Arc::new(Mutex::new(Vec::new())),
         };
         storage.sync_dir()?;
 
@@ -428,6 +440,11 @@ impl LsmStorageInner {
         self.state.read().memtable.sync_wal()
     }
 
+    pub fn add_compaction_filter(&self, compaction_filter: CompactionFilter) {
+        let mut compaction_filters = self.compaction_filters.lock();
+        compaction_filters.push(compaction_filter);
+    }
+
     /// Get a key from the storage. In day 7, this can be further optimized by using a bloom filter.
     pub fn get(&self, key: &[u8]) -> Result<Option<Bytes>> {
         let snapshot = {

mini-lsm/src/tests/harness.rs

@@ -341,6 +341,9 @@ pub fn check_compaction_ratio(storage: Arc<MiniLsm>) {
             for idx in 1..level_size.len() {
                 let prev_size = level_size[idx - 1];
                 let this_size = level_size[idx];
+                if this_size == 0 {
+                    continue;
+                }
                 assert!(
                     // do not add hard requirement on level size multiplier considering bloom filters...
                     this_size as f64 / prev_size as f64 >= (level_size_multiplier as f64 - 0.5),