⚡ Bolt: Zero-allocation BlockId references in batch storage fetch

.jules/bolt.md

@@ -36,3 +36,9 @@
 ## 2024-05-14 - Remove hot-path BlockId cloning in scheduler tick
 **Learning:** In the fast path of the scheduler (`process_instance`), `BlockId` was being cloned and looked up in a HashMap for every incomplete step on every tick, regardless of whether a deadline was configured. The fix avoids this allocation using zero-allocation references and an early return.
 **Action:** Always verify if nested loops are lazily evaluating or bypassing unnecessary object clones/lookups on hot execution paths. Utilize Rust's HashMap with custom Borrow implementations or locally constructed reference maps to query without allocating strings.
+## 2025-10-28 - [Zero-Allocation Reference Tuples in Hot Path Iterators]
+**Learning:** In the fast path of the scheduler (), passing  by reference into  avoids allocating and copying s for every step that requires a deadline check. Prior to this,  was cloned on every iteration inside a loop processing active steps, introducing significant memory overhead across the cluster.
+**Action:** Always prefer accepting references within collections () for database batch operations if the caller only holds references, preventing O(N) string clones on execution hot paths.
+## 2025-10-28 - [Zero-Allocation Reference Tuples in Hot Path Iterators]
+**Learning:** In the fast path of the scheduler (scheduler.rs:1026), passing &BlockId by reference into get_block_outputs_batch avoids allocating and copying Strings for every step that requires a deadline check. Prior to this, BlockId was cloned on every iteration inside a loop processing active steps, introducing significant memory overhead across the cluster.
+**Action:** Always prefer accepting references within collections (&[(InstanceId, &BlockId)]) for database batch operations if the caller only holds references, preventing O(N) string clones on execution hot paths.

orch8-engine/src/scheduler.rs

@@ -686,7 +686,7 @@ async fn process_waiting_deadlines(
         for block in &seq.blocks {
             if let orch8_types::sequence::BlockDefinition::Step(step_def) = block {
                 if step_def.deadline.is_some() {
-                    deadline_keys.push((instance.id, step_def.id.clone()));
+                    deadline_keys.push((instance.id, &step_def.id));
                 }
             }
         }
@@ -1025,11 +1025,14 @@ async fn process_instance(
 
     // Fast path SLA deadline check for all steps BEFORE concurrency checks.
     // Batch-fetch any previous block outputs so the loop is N queries -> 1 query.
-    let deadline_keys: Vec<(InstanceId, BlockId)> = blocks
+    // ⚡ Bolt: By passing &s.id as a reference to get_block_outputs_batch, we avoid
+    // an unnecessary `.clone()` on the `BlockId` (String allocation) for every deadline step
+    // inside this hot scheduler tick loop.
+    let deadline_keys: Vec<(InstanceId, &BlockId)> = blocks
         .iter()
         .filter_map(|b| match b {
             orch8_types::sequence::BlockDefinition::Step(s) if s.deadline.is_some() => {
-                Some((instance.id, s.id.clone()))
+                Some((instance.id, &s.id))
             }
             _ => None,
         })

orch8-engine/tests/feature_gaps.rs

@@ -498,7 +498,8 @@ async fn sqlite_get_batch_chunking_does_not_drop_keys() {
         keys.push((instance, block_id));
     }
 
-    let batch = storage.get_block_outputs_batch(&keys).await.unwrap();
+    let ref_keys: Vec<(InstanceId, &BlockId)> = keys.iter().map(|(i, b)| (*i, b)).collect();
+    let batch = storage.get_block_outputs_batch(&ref_keys).await.unwrap();
     assert_eq!(batch.len(), 450, "batch must return all 450 outputs");
 
     // Spot-check a few keys.

orch8-storage/src/encrypting.rs

@@ -673,7 +673,7 @@ impl crate::OutputStore for EncryptingStorage {
     }
     async fn get_block_outputs_batch(
         &self,
-        keys: &[(InstanceId, orch8_types::ids::BlockId)],
+        keys: &[(InstanceId, &orch8_types::ids::BlockId)],
     ) -> Result<
         std::collections::HashMap<
             (InstanceId, orch8_types::ids::BlockId),

orch8-storage/src/lib.rs

@@ -664,9 +664,12 @@ pub trait OutputStore: Send + Sync + 'static {
     ///
     /// Returns a map from `(InstanceId, BlockId)` to the latest output
     /// (ordered by `created_at DESC`). Missing pairs are omitted.
+    ///
+    /// Performance Note: `keys` accepts `&BlockId` by reference inside the tuple
+    /// to avoid expensive allocations/clones in hot paths like the scheduler loop.
     async fn get_block_outputs_batch(
         &self,
-        keys: &[(InstanceId, BlockId)],
+        keys: &[(InstanceId, &BlockId)],
     ) -> Result<HashMap<(InstanceId, BlockId), BlockOutput>, StorageError>;
 
     async fn get_all_outputs(

orch8-storage/src/postgres/mod.rs

@@ -545,7 +545,7 @@ impl crate::OutputStore for PostgresStorage {
 
     async fn get_block_outputs_batch(
         &self,
-        keys: &[(InstanceId, BlockId)],
+        keys: &[(InstanceId, &BlockId)],
     ) -> Result<std::collections::HashMap<(InstanceId, BlockId), BlockOutput>, StorageError> {
         outputs::get_batch(self, keys).await
     }

orch8-storage/src/postgres/outputs.rs

@@ -68,7 +68,7 @@ pub(super) async fn get(
 
 pub(super) async fn get_batch(
     store: &PostgresStorage,
-    keys: &[(InstanceId, BlockId)],
+    keys: &[(InstanceId, &BlockId)],
 ) -> Result<std::collections::HashMap<(InstanceId, BlockId), BlockOutput>, StorageError> {
     if keys.is_empty() {
         return Ok(std::collections::HashMap::new());

orch8-storage/src/sqlite/mod.rs

@@ -641,7 +641,7 @@ impl crate::OutputStore for SqliteStorage {
 
     async fn get_block_outputs_batch(
         &self,
-        keys: &[(InstanceId, BlockId)],
+        keys: &[(InstanceId, &BlockId)],
     ) -> Result<std::collections::HashMap<(InstanceId, BlockId), BlockOutput>, StorageError> {
         outputs::get_batch(self, keys).await
     }

orch8-storage/src/sqlite/outputs.rs

@@ -45,7 +45,7 @@ const GET_BATCH_CHUNK_SIZE: usize = 400;
 
 pub(super) async fn get_batch(
     storage: &SqliteStorage,
-    keys: &[(InstanceId, BlockId)],
+    keys: &[(InstanceId, &BlockId)],
 ) -> Result<std::collections::HashMap<(InstanceId, BlockId), BlockOutput>, StorageError> {
     if keys.is_empty() {
         return Ok(std::collections::HashMap::new());