wip2

config/toydb.yaml

@@ -12,17 +12,10 @@ listen_raft: 0.0.0.0:9705
 data_dir: data
 compact_threshold: 0.2
 
-# Whether to fsync writes. Fsyncing guarantees that committed data is persisted
-# to disk, but has a high performance penalty. Disabling fsync and relying on
-# cluster redundancy for data durability may be a reasonable trade-off, although
-# this can compromise Raft linearizability guarantees in rare edge cases where
-# committed entries lose majority.
-sync: true
-
 # Raft log storage engine
-# - hybrid: (default) stores committed entries in an indexed append-only file, the rest in memory.
-# - memory: stores all entries in memory.
-storage_raft: hybrid
+# - bitcask (default): an append-only log-structured store.
+# - memory: an in-memory store using the Rust standard library's BTreeMap.
+storage_raft: bitcask
 
 # SQL key-value storage engine
 # - bitcask (default): an append-only log-structured store.

src/bin/toydb.rs

@@ -35,11 +35,6 @@ async fn main() -> Result<()> {
     simplelog::SimpleLogger::init(loglevel, logconfig.build())?;
 
     let path = std::path::Path::new(&cfg.data_dir);
-    let raft_store: Box<dyn storage::log::Store> = match cfg.storage_raft.as_str() {
-        "hybrid" | "" => Box::new(storage::log::Hybrid::new(path, cfg.sync)?),
-        "memory" => Box::new(storage::log::Memory::new()),
-        name => return Err(Error::Config(format!("Unknown Raft storage engine {}", name))),
-    };
     let raft_state: Box<dyn raft::State> = match cfg.storage_sql.as_str() {
         "bitcask" | "" => {
             let engine =
@@ -52,13 +47,22 @@ async fn main() -> Result<()> {
         }
         name => return Err(Error::Config(format!("Unknown SQL storage engine {}", name))),
     };
+    let raft_server = match cfg.storage_raft.as_str() {
+        "bitcask" | "" => {
+            let raft_log = raft::Log::new(storage::engine::BitCask::new_compact(
+                path.join("log"),
+                cfg.compact_threshold,
+            )?)?;
+            raft::Server::new(&cfg.id, cfg.peers, raft_log, raft_state).await?
+        }
+        "memory" => {
+            let raft_log = raft::Log::new(storage::engine::Memory::new())?;
+            raft::Server::new(&cfg.id, cfg.peers, raft_log, raft_state).await?
+        }
+        name => return Err(Error::Config(format!("Unknown Raft storage engine {}", name))),
+    };
 
-    Server::new(&cfg.id, cfg.peers, raft_store, raft_state)
-        .await?
-        .listen(&cfg.listen_sql, &cfg.listen_raft)
-        .await?
-        .serve()
-        .await
+    Server::new(raft_server).listen(&cfg.listen_sql, &cfg.listen_raft).await?.serve().await
 }
 
 #[derive(Debug, Deserialize)]
@@ -70,7 +74,6 @@ struct Config {
     log_level: String,
     data_dir: String,
     compact_threshold: f64,
-    sync: bool,
     storage_raft: String,
     storage_sql: String,
 }
@@ -86,7 +89,7 @@ impl Config {
             .set_default("data_dir", "data")?
             .set_default("compact_threshold", 0.2)?
             .set_default("sync", true)?
-            .set_default("storage_raft", "hybrid")?
+            .set_default("storage_raft", "bitcask")?
             .set_default("storage_sql", "bitcask")?
             .add_source(config::File::with_name(file))
             .add_source(config::Environment::with_prefix("TOYDB"))