neon_local: enable configuring split_threshold

control_plane/src/local_env.rs

@@ -152,6 +152,9 @@ pub struct NeonStorageControllerConf {
     /// Heartbeat timeout before marking a node offline
     #[serde(with = "humantime_serde")]
     pub max_unavailable: Duration,
+
+    /// Threshold for auto-splitting a tenant into shards
+    pub split_threshold: Option<u64>,
 }
 
 impl NeonStorageControllerConf {
@@ -164,6 +167,7 @@ impl Default for NeonStorageControllerConf {
     fn default() -> Self {
         Self {
             max_unavailable: Self::DEFAULT_MAX_UNAVAILABLE_INTERVAL,
+            split_threshold: None,
         }
     }
 }

control_plane/src/storage_controller.rs

@@ -305,6 +305,10 @@ impl StorageController {
             ));
         }
 
+        if let Some(split_threshold) = self.config.split_threshold.as_ref() {
+            args.push(format!("--split-threshold={split_threshold}"))
+        }
+
         background_process::start_process(
             COMMAND,
             &self.env.base_data_dir,