libsql-server: use LRU cache to store active namespaces

This is a port of Marin's libsql/sqld#689 This PR replaces the namespace store dumb hashmap with an LRU cache to bound the maximum number of namespaces loaded into memory while unbounding the number of namespaces allocated on a sqld instance. Additionally, this enables fully concurrent access to namespaces by removing the global lock on the namespace store. Co-authored-by: Piotr Sarna <[email protected]>
tursodatabase · Dec 1, 2023 · 5f0be83 · 5f0be83
1 parent b3145d8
commit 5f0be83
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Showing 3 changed files with 205 additions and 95 deletions.
diff --git a/libsql-server/Cargo.toml b/libsql-server/Cargo.toml
@@ -76,6 +76,7 @@ tracing-subscriber = { version = "0.3.16", features = ["env-filter"] }
 http-body = "0.4"
 url = { version = "2.3", features = ["serde"] }
 uuid = { version = "1.3", features = ["v4", "serde"] }
+moka = { version = "0.12.1", features = ["future"] }
 
 [dev-dependencies]
 arbitrary = { version = "1.3.0", features = ["derive_arbitrary"] }

diff --git a/libsql-server/src/error.rs b/libsql-server/src/error.rs
@@ -92,6 +92,9 @@ pub enum Error {
     UrlParseError(#[from] url::ParseError),
     #[error("Namespace store has shutdown")]
     NamespaceStoreShutdown,
+    // This is for errors returned by moka
+    #[error(transparent)]
+    Ref(#[from] std::sync::Arc<Self>),
 }
 
 trait ResponseError: std::error::Error {
@@ -105,6 +108,12 @@ trait ResponseError: std::error::Error {
 impl ResponseError for Error {}
 
 impl IntoResponse for Error {
+    fn into_response(self) -> axum::response::Response {
+        (&self).into_response()
+    }
+}
+
+impl IntoResponse for &Error {
     fn into_response(self) -> axum::response::Response {
         use Error::*;
 
@@ -150,6 +159,7 @@ impl IntoResponse for Error {
             PrimaryStreamInterupted => self.format_err(StatusCode::INTERNAL_SERVER_ERROR),
             UrlParseError(_) => self.format_err(StatusCode::BAD_REQUEST),
             NamespaceStoreShutdown => self.format_err(StatusCode::SERVICE_UNAVAILABLE),
+            Ref(this) => this.as_ref().into_response(),
         }
     }
 }
@@ -224,7 +234,7 @@ pub enum LoadDumpError {
 
 impl ResponseError for LoadDumpError {}
 
-impl IntoResponse for LoadDumpError {
+impl IntoResponse for &LoadDumpError {
     fn into_response(self) -> axum::response::Response {
         use LoadDumpError::*;
 
@@ -244,7 +254,7 @@ impl IntoResponse for LoadDumpError {
 
 impl ResponseError for ForkError {}
 
-impl IntoResponse for ForkError {
+impl IntoResponse for &ForkError {
     fn into_response(self) -> axum::response::Response {
         match self {
             ForkError::Internal(_)