# Ray 2.41.0 — Ray-2.41.0

- Product: Ray (https://whatsnew.fyi/product/ray)
- Vendor: Anyscale
- Date: 2025-01-23
- Version: 2.41.0
- Original notes: https://github.com/ray-project/ray/releases/tag/ray-2.41.0
- Permalink: https://whatsnew.fyi/product/ray/releases/2.41.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **added** — Expression support for filters in Ray Data
- **added** — Support partition_cols in write_parquet for Ray Data
- **added** — Multi-directional sort over Ray Data datasets
- **added** — Output JSON structured log files for system and application logs in Ray Train
- **added** — Support for AMD ROCR_VISIBLE_DEVICES in Ray Train
- **added** — Allow users to configure optuna storage in optuna_search
- **added** — Support for external Envs to new API stack in RLlib with custom tcp-capable EnvRunner
- **added** — Sequence sampling to EpisodeReplayBuffer in offline RL
- **added** — ExecutionCallback interface in Ray Data
- **added** — Seed for read files in Ray Data
- **added** — Support for individual lambda-style callbacks in RLlib Callbacks API
- **changed** — Use dask 2022.10.2 in Ray Data
- **changed** — Upgrade Arrow version from 17 to 18 in Ray Data
- **changed** — Update hudi version to 0.2.0 in Ray Data
- **changed** — Make select_columns and rename_columns use Project operator in Ray Data
- **changed** — Improved request_id generation to reduce proxy CPU overhead in Ray Serve
- **changed** — Tune GC threshold by default in proxy in Ray Serve
- **changed** — Use pickle.dumps for faster serialization from proxy to replica in Ray Serve
- **fixed** — Fix groupby hang when value contains np.nan in Ray Data
- **fixed** — Fix bug where file_extensions doesn't work with compound extensions in Ray Data
- **deprecated** — Default behavior for sync methods will change in a future release to run in a threadpool by default in Ray Serve

#### Highlights

- Major update of RLlib docs and example scripts for the new API stack.

#### Ray Libraries

##### Ray Data

🎉 New Features:

- Expression support for filters (#49016) 
- Support `partition_cols` in `write_parquet` (#49411)
- Feature: implement multi-directional sort over Ray Data datasets (#49281)

💫 Enhancements:

- Use dask 2022.10.2 (#48898) 
- Clarify schema validation error (#48882)
- Raise `ValueError` when the data sort key is `None` (#48969) 
- Provide more messages when webdataset format is error (#48643) 
- Upgrade Arrow version from 17 to 18 (#48448)
- Update `hudi` version to 0.2.0 (#48875) 
- `webdataset`: expand JSON objects into individual samples (#48673)
- Support passing kwargs to map tasks. (#49208) 
- Add `ExecutionCallback` interface (#49205) 
- Add seed for read files (#49129)
- Make `select_columns` and `rename_columns` use Project operator (#49393)

🔨 Fixes:

- Fix partial function name parsing in `map_groups` (#48907) 
- Always launch one task for `read_sql` (#48923) 
- Reimplement of fix memory pandas (#48970)
- `webdataset`: flatten return args (#48674) 
- Handle `numpy > 2.0.0` behaviour in `_create_possibly_ragged_ndarray` (#48064)
- Fix `DataContext` sealing for multiple datasets. (#49096) 
- Fix `to_tf` for `List` types (#49139) 
- Fix type mismatch error while mapping nullable column (#49405) 
- Datasink: support passing write results to `on_write_completes` (#49251)
- Fix `groupby` hang when value contains `np.nan` (#49420)
- Fix bug where `file_extensions` doesn't work with compound extensions (#49244)
- Fix map operator fusion when concurrency is set (#49573) 

##### Ray Train

🎉 New Features:

- Output JSON structured log files for system and application logs (#49414)
- Add support for AMD ROCR_VISIBLE_DEVICES (#49346)

💫 Enhancements:

- Implement Train Tune API Revamp REP (#49376, #49467, #49317, #49522)

🏗 Architecture refactoring:

- LightGBM: Rewrite `get_network_params` implementation (#49019)

##### Ray Tune

🎉 New Features:

- Update `optuna_search` to allow users to configure optuna storage (#48547)

🏗 Architecture refactoring:

- Make changes to support Train Tune API Revamp REP (#49308, #49317, #49519)

##### Ray Serve

💫 Enhancements:

- Improved request_id generation to reduce proxy CPU overhead (#49537)
- Tune GC threshold by default in proxy (#49720)
- Use `pickle.dumps` for faster serialization from `proxy` to `replica` (#49539)

🔨 Fixes:

- Handle nested ‘=’ in serve run arguments (#49719)
- Fix bug when `ray.init()` is called multiple times with different `runtime_envs` (#49074)

🗑️ Deprecations:

- Adds a warning that the default behavior for sync methods will change in a future release. They will be run in a threadpool by default. You can opt into this behavior early by setting `RAY_SERVE_RUN_SYNC_IN_THREADPOOL=1`. (#48897)

##### RLlib

🎉 New Features:

- Add support for external Envs to new API stack: New example script and custom tcp-capable EnvRunner. (#49033)

💫 Enhancements:

- Offline RL:
  - Add sequence sampling to `EpisodeReplayBuffer`. (#48116)
  - Allow incomplete `SampleBatch` data and fully compressed observations. (#48699)
  - Add option to customize `OfflineData`. (#49015)
  - Enable offline training without specifying an environment. (#49041)
  - Various fixes: #48309, #49194, #49195
- APPO/IMPALA acceleration (new API stack):
  - Add support for `AggregatorActors` per Learner. (#49284)
  - Auto-sleep time AND thread-safety for MetricsLogger. (#48868)
  - Activate APPO cont. actions release- and CI tests (HalfCheetah-v1 and Pendulum-v1 new in `tuned_examples`). (#49068)
  - Add "burn-in" period setting to the training of stateful RLModules. (#49680)
- Callbacks API: Add support for individual lambda-style callbacks. (#49511)
- Other enhancements: #49687, #49714, #49693, #49497, #49800, #49098

📖 Documentation:

- New

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