add retries + sqlite pragmas for light client database

Author: ss-es

hotshot-query-service/Cargo.toml

@@ -23,7 +23,12 @@ default = ["file-system-data-source", "metrics-data-source", "sql-data-source"]
 # Enables support for an embedded SQLite database instead of PostgreSQL.
 # Ideal for lightweight nodes that benefit from pruning and merklized state storage,
 # offering advantages over file system storage.
-embedded-db = ["sqlx/sqlite"]
+embedded-db = ["sqlx/sqlite", "sqlite-options"]
+
+# Exposes shared SQLite connection helpers (e.g. `sqlite_options`) for callers that build their
+# own pool. Separate from `embedded-db` so clients can opt in to the helpers without flipping the
+# workspace into SQLite mode.
+sqlite-options = ["sqlx/sqlite"]
 
 # Enable the availability data source backed by the local file system.
 file-system-data-source = ["atomic_store"]

hotshot-query-service/src/data_source/storage/sql.rs

@@ -247,12 +247,7 @@ impl Default for Config {
 #[cfg(feature = "embedded-db")]
 impl Default for Config {
     fn default() -> Self {
-        SqliteConnectOptions::default()
-            .journal_mode(sqlx::sqlite::SqliteJournalMode::Wal)
-            .busy_timeout(Duration::from_secs(30))
-            .auto_vacuum(sqlx::sqlite::SqliteAutoVacuum::Incremental)
-            .create_if_missing(true)
-            .into()
+        crate::sqlite_options::sqlite_options().into()
     }
 }
 

hotshot-query-service/src/lib.rs

@@ -424,6 +424,8 @@ pub mod metrics;
 pub mod migration;
 pub mod node;
 mod resolvable;
+#[cfg(feature = "sqlite-options")]
+pub mod sqlite_options;
 pub mod status;
 pub mod task;
 pub mod testing;

hotshot-query-service/src/sqlite_options.rs

@@ -0,0 +1,25 @@
+//! Shared SQLite connection defaults.
+//!
+//! Used by both the embedded-db variant of this crate and by external clients (e.g. the light
+//! client) that build their own pool. Keeping the pragma choices in one place ensures every
+//! SQLite database in the workspace runs with the same journaling, locking, and vacuum settings.
+
+use std::time::Duration;
+
+use sqlx::sqlite::{SqliteAutoVacuum, SqliteConnectOptions, SqliteJournalMode};
+
+/// Default [`SqliteConnectOptions`] for SQLite databases in this workspace.
+///
+/// WAL journaling is the load-bearing choice: under the default rollback journal, any writer
+/// holds an exclusive lock that blocks readers on other connections, which produces spurious
+/// `SQLITE_BUSY` ("database is locked") errors under concurrent access. WAL lets readers and
+/// the single writer proceed in parallel.
+///
+/// Callers add `.filename(...)` (or use `:memory:`) on top.
+pub fn sqlite_options() -> SqliteConnectOptions {
+    SqliteConnectOptions::default()
+        .journal_mode(SqliteJournalMode::Wal)
+        .busy_timeout(Duration::from_secs(30))
+        .auto_vacuum(SqliteAutoVacuum::Incremental)
+        .create_if_missing(true)
+}

light-client/Cargo.toml

@@ -21,7 +21,7 @@ derive_builder = { workspace = true }
 derive_more = { workspace = true }
 espresso-types = { workspace = true }
 futures = { workspace = true }
-hotshot-query-service = { workspace = true }
+hotshot-query-service = { workspace = true, features = ["sqlite-options"] }
 hotshot-query-service-types = { workspace = true }
 hotshot-types = { workspace = true }
 jf-advz = { workspace = true }