feldera · blp · Mar 27, 2026 · Mar 30, 2026
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/crates/adapters/src/controller.rs b/crates/adapters/src/controller.rs
@@ -58,7 +58,7 @@ use dbsp::circuit::metrics::{
     DBSP_STEP_LATENCY_MICROSECONDS, FILES_CREATED, FILES_DELETED, TOTAL_LATE_RECORDS,
 };
 use dbsp::circuit::tokio::TOKIO;
-use dbsp::circuit::{CheckpointCommitter, CircuitStorageConfig, DevTweaks, Mode};
+use dbsp::circuit::{CheckpointCommitter, CircuitStorageConfig, Mode};
 use dbsp::samply::{MARKER_BYTES, Markers, SamplySpan};
 use dbsp::storage::backend::{StorageBackend, StoragePath};
 use dbsp::utils::process_rss_bytes;
@@ -159,8 +159,8 @@ pub use feldera_types::config::{
     RuntimeConfig, TransportConfig,
 };
 use feldera_types::config::{
-    DEFAULT_MAX_WORKER_BATCH_SIZE, FileBackendConfig, FtConfig, FtModel, OutputBufferConfig,
-    StorageBackendConfig, SyncConfig,
+    DEFAULT_MAX_WORKER_BATCH_SIZE, DevTweaks, FileBackendConfig, FtConfig, FtModel,
+    OutputBufferConfig, StorageBackendConfig, SyncConfig,
 };
 use feldera_types::constants::{STATE_FILE, STEPS_FILE};
 use feldera_types::format::json::{JsonFlavor, JsonParserConfig, JsonUpdateFormat};
@@ -4390,7 +4390,10 @@ impl ControllerInit {
         pipeline_config: &PipelineConfig,
         storage: Option<CircuitStorageConfig>,
     ) -> Result<CircuitConfig, ControllerError> {
-        let dev_tweaks = DevTweaks::from_config(&pipeline_config.global.dev_tweaks);
+        let dev_tweaks = pipeline_config.global.dev_tweaks.clone();
+        if dev_tweaks != DevTweaks::default() {
+            info!("using non-default `dev_tweaks`: {dev_tweaks:#?}")
+        }
 
         let mut max_rss_mb = pipeline_config.global.max_rss_mb;
 

diff --git a/crates/adapters/src/server.rs b/crates/adapters/src/server.rs
@@ -625,13 +625,7 @@ pub fn run_server(
 
     // Install stack overflow handler early, before creating the controller and parsing DevTweaks.
     #[cfg(target_family = "unix")]
-    if config
-        .global
-        .dev_tweaks
-        .get("stack_overflow_backtrace")
-        .cloned()
-        == Some(serde_json::Value::Bool(true))
-    {
+    if config.global.dev_tweaks.stack_overflow_backtrace() {
         unsafe {
             use crate::server::stack_overflow_backtrace::enable_stack_overflow_backtrace_with_limit;
 

diff --git a/crates/adapters/src/util.rs b/crates/adapters/src/util.rs
@@ -718,7 +718,7 @@ pub(crate) fn run_in_posix_runtime<F>(
     F: FnOnce() + Send + 'static,
 {
     use dbsp::Runtime;
-    use dbsp::circuit::{CircuitConfig, CircuitStorageConfig, DevTweaks, Layout, Mode};
+    use dbsp::circuit::{CircuitConfig, CircuitStorageConfig, Layout, Mode};
     use feldera_types::config::{StorageCacheConfig, StorageConfig, StorageOptions};
     use std::sync::{Arc, Mutex};
 
@@ -742,7 +742,7 @@ pub(crate) fn run_in_posix_runtime<F>(
             )
             .expect("failed to configure storage"),
         ),
-        dev_tweaks: DevTweaks::default(),
+        dev_tweaks: Default::default(),
     };
 
     let test_fn: Arc<Mutex<Option<F>>> = Arc::new(Mutex::new(Some(test_fn)));

diff --git a/crates/buffer-cache/Cargo.toml b/crates/buffer-cache/Cargo.toml
@@ -13,6 +13,7 @@ description = "Weighted in-memory buffer caches with LRU and S3-FIFO eviction"
 [dependencies]
 crossbeam-utils = { workspace = true }
 enum-map = { workspace = true }
+feldera-types = { workspace = true }
 quick_cache = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 tracing = { workspace = true }

diff --git a/crates/buffer-cache/src/builder.rs b/crates/buffer-cache/src/builder.rs
@@ -1,39 +1,12 @@
 use crate::ThreadType;
 use crate::{CacheEntry, LruCache, S3FifoCache, SharedBufferCache};
 use enum_map::{Enum, EnumMap};
-use serde::{Deserialize, Serialize};
+use feldera_types::config::dev_tweaks::{BufferCacheAllocationStrategy, BufferCacheStrategy};
 use std::fmt::Debug;
 use std::hash::{BuildHasher, Hash, RandomState};
 use std::marker::PhantomData;
 use tracing::warn;
 
-/// Selects which eviction strategy backs a cache instance.
-#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
-#[serde(rename_all = "snake_case")]
-pub enum BufferCacheStrategy {
-    /// Use the sharded S3-FIFO cache backed by `quick_cache`.
-    #[default]
-    S3Fifo,
-
-    /// Use the mutex-protected weighted LRU cache.
-    Lru,
-}
-
-/// Controls how caches are shared across a foreground/background worker pair.
-#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
-#[serde(rename_all = "snake_case")]
-pub enum BufferCacheAllocationStrategy {
-    /// Share one cache across a foreground/background worker pair.
-    #[default]
-    SharedPerWorkerPair,
-
-    /// Create a separate cache for each foreground/background thread.
-    PerThread,
-
-    /// Share one cache across all foreground/background threads.
-    Global,
-}
-
 /// Builds the cache layout used by DBSP runtime worker pairs.
 pub struct BufferCacheBuilder<K, V, S = RandomState> {
     /// Eviction strategy used for newly constructed caches.

diff --git a/crates/buffer-cache/src/lib.rs b/crates/buffer-cache/src/lib.rs
@@ -8,7 +8,8 @@ mod thread_type;
 use std::any::Any;
 use std::sync::Arc;
 
-pub use builder::{BufferCacheAllocationStrategy, BufferCacheBuilder, BufferCacheStrategy};
+pub use builder::BufferCacheBuilder;
+use feldera_types::config::dev_tweaks::BufferCacheStrategy;
 pub use lru::LruCache;
 pub use s3_fifo::S3FifoCache;
 pub use thread_type::ThreadType;

diff --git a/crates/buffer-cache/src/lru.rs b/crates/buffer-cache/src/lru.rs
@@ -1,4 +1,6 @@
-use crate::{BufferCache, BufferCacheStrategy, CacheEntry};
+use feldera_types::config::dev_tweaks::BufferCacheStrategy;
+
+use crate::{BufferCache, CacheEntry};
 use std::any::Any;
 use std::collections::BTreeMap;
 use std::fmt::Debug;

diff --git a/crates/buffer-cache/src/s3_fifo.rs b/crates/buffer-cache/src/s3_fifo.rs
@@ -1,4 +1,5 @@
-use crate::{BufferCache, BufferCacheStrategy, CacheEntry};
+use crate::{BufferCache, CacheEntry};
+use feldera_types::config::dev_tweaks::BufferCacheStrategy;
 use quick_cache::{OptionsBuilder, Weighter, sync::Cache as QuickCache};
 use std::any::Any;
 use std::hash::{BuildHasher, Hash, RandomState};

diff --git a/crates/buffer-cache/src/tests/builder.rs b/crates/buffer-cache/src/tests/builder.rs
@@ -1,6 +1,6 @@
-use crate::{
-    BufferCacheAllocationStrategy, BufferCacheBuilder, BufferCacheStrategy, CacheEntry, ThreadType,
-};
+use feldera_types::config::dev_tweaks::{BufferCacheAllocationStrategy, BufferCacheStrategy};
+
+use crate::{BufferCacheBuilder, CacheEntry, ThreadType};
 use std::sync::Arc;
 
 #[derive(Clone)]

diff --git a/crates/dbsp/benches/cursor_list.rs b/crates/dbsp/benches/cursor_list.rs
@@ -7,7 +7,7 @@
 //!
 //! Run with: cargo bench -p dbsp --bench cursor_list
 
-use dbsp::circuit::{CircuitConfig, CircuitStorageConfig, DevTweaks, Layout, Mode};
+use dbsp::circuit::{CircuitConfig, CircuitStorageConfig, Layout, Mode};
 use dbsp::{
     OrdIndexedZSet, Runtime, ZWeight,
     trace::cursor::CursorList,
@@ -102,7 +102,7 @@ fn bench(storage: bool) {
             )
             .expect("failed to configure POSIX storage"),
         ),
-        dev_tweaks: DevTweaks::default(),
+        dev_tweaks: Default::default(),
     };
 
     let results: Arc<Mutex<Vec<BenchResult>>> = Arc::new(Mutex::new(Vec::new()));

diff --git a/crates/dbsp/benches/input_map_ingest.rs b/crates/dbsp/benches/input_map_ingest.rs
@@ -1,6 +1,6 @@
 use anyhow::{Context, Result, anyhow};
 use crossbeam::channel::{Sender, bounded};
-use dbsp::circuit::{CircuitConfig, CircuitStorageConfig, DevTweaks, Layout, Mode};
+use dbsp::circuit::{CircuitConfig, CircuitStorageConfig, Layout, Mode};
 use dbsp::{
     Runtime,
     mimalloc::MiMalloc,
@@ -54,7 +54,7 @@ fn main() -> Result<()> {
             )
             .context("failed to configure POSIX storage backend")?,
         ),
-        dev_tweaks: DevTweaks::default(),
+        dev_tweaks: Default::default(),
     };
 
     let total_batches = (TOTAL_RECORDS / BATCH_SIZE as u64) as usize;

diff --git a/crates/dbsp/benches/list_merger.rs b/crates/dbsp/benches/list_merger.rs
@@ -7,7 +7,7 @@
 //!
 //! Run with: `cargo bench -p dbsp --bench list_merger`
 
-use dbsp::circuit::{CircuitConfig, CircuitStorageConfig, DevTweaks, Layout, Mode};
+use dbsp::circuit::{CircuitConfig, CircuitStorageConfig, Layout, Mode};
 use dbsp::{
     OrdIndexedZSet, Runtime, ZWeight,
     trace::{Batch as DynBatch, BatchLocation, BatchReader as DynBatchReader, Builder, ListMerger},
@@ -125,7 +125,7 @@ fn bench(generate_on_storage: bool) {
             )
             .expect("failed to configure POSIX storage"),
         ),
-        dev_tweaks: DevTweaks::default(),
+        dev_tweaks: Default::default(),
     };
 
     let results: Arc<Mutex<Vec<BenchResult>>> = Arc::new(Mutex::new(Vec::new()));

diff --git a/crates/dbsp/src/circuit.rs b/crates/dbsp/src/circuit.rs
@@ -38,7 +38,7 @@ pub use circuit_builder::{
     NestedCircuit, NodeId, OwnershipPreference, RootCircuit, Scope, Stream, WithClock,
 };
 pub use dbsp_handle::{
-    CheckpointCommitter, CircuitConfig, CircuitStorageConfig, DBSPHandle, DevTweaks, Host, Layout,
+    CheckpointCommitter, CircuitConfig, CircuitStorageConfig, DBSPHandle, Host, Layout,
     LayoutError, Mode, StorageCacheConfig, StorageConfig, StorageOptions, adaptive_joins_enabled,
     balancer_balance_tax, balancer_key_distribution_refresh_threshold,
     balancer_min_absolute_improvement_threshold, balancer_min_relative_improvement_threshold,