# Ray 2.39.0 — Ray-2.39.0

- Product: Ray (https://whatsnew.fyi/product/ray)
- Vendor: Anyscale
- Date: 2024-11-13
- Version: 2.39.0
- Original notes: https://github.com/ray-project/ray/releases/tag/ray-2.39.0
- Permalink: https://whatsnew.fyi/product/ray/releases/2.39.0

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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- **fixed** — Fixed InvalidObjectError edge case with Dataset.split()
- **fixed** — Made Concatenator preserve order of concatenated columns
- **changed** — Marked num_rows_per_file parameter of write APIs as experimental
- **fixed** — transform_batch no longer fails on missing columns
- **changed** — Dataset.count() now uses a Count logical operator
- **removed** — Removed long-deprecated set_progress_bars
- **fixed** — Safely check if the storage filesystem is pyarrow.fs.S3FileSystem
- **added** — Cancelled requests now return a serve.RequestCancelledError
- **added** — Exposed application source in app details model
- **fixed** — Basic HTTP deployments will now return "Internal Server Error" instead of a traceback to match FastAPI behavior
- **fixed** — Fixed an issue where high values of max_ongoing_requests couldn't be reached due to an interaction with core's max_concurrency
- **fixed** — Fixed an edge case where pending requests were not canceled properly
- **removed** — Removed deprecated API to set route_prefix per-deployment
- **changed** — Upgrade to gymnasium==1.0.0 with support for new API for vector env resets
- **added** — Add off-policy'ness metric to new API stack
- **added** — Validate episodes before adding them to the buffer
- **added** — Support all reduce collective in aDAG
- **added** — Add visualization of compiled graphs
- **changed** — The distributed debugger can now be used without having to set RAY_DEBUG=1
- **added** — Support asyncio.gather on multiple CompiledDAGFutures

#### Ray Libraries

##### Ray Data

🔨 Fixes:
- Fixed InvalidObjectError edge case with Dataset.split() (https://github.com/ray-project/ray/pull/48130)
- Made Concatenator preserve order of concatenated columns (https://github.com/ray-project/ray/pull/47997)

📖 Documentation:
- Improved documentation around Parquet column and predicate pushdown (https://github.com/ray-project/ray/pull/48095)
- Marked num_rows_per_file parameter of write APIs as experimental (https://github.com/ray-project/ray/pull/48208)
- One hot encoder now returns an encoded vector (https://github.com/ray-project/ray/pull/48173)
- transform_batch no longer fails on missing columns (https://github.com/ray-project/ray/pull/48137)

🏗 Architecture refactoring:
- Dataset.count() now uses a Count logical operator (https://github.com/ray-project/ray/pull/48126)

🗑 Deprecations:
- Removed long-deprecated set_progress_bars (https://github.com/ray-project/ray/pull/48203)

##### Ray Train

🔨 Fixes:
- Safely check if the storage filesystem is `pyarrow.fs.S3FileSystem` (#48216)

##### Ray Tune

🔨 Fixes:
- Safely check if the storage filesystem is `pyarrow.fs.S3FileSystem` (#48216)

##### Ray Serve

💫 Enhancements:
- Cancelled requests now return a serve.RequestCancelledError (https://github.com/ray-project/ray/pull/48444)
- Exposed application source in app details model (https://github.com/ray-project/ray/pull/45522)

🔨 Fixes:
- Basic HTTP deployments will now return “Internal Server Error” instead of a traceback to match FastAPI behavior (https://github.com/ray-project/ray/pull/48491)
- Fixed an issue where high values of max_ongoing_requests couldn’t be reached due to an interaction with core’s max_concurrency (https://github.com/ray-project/ray/pull/48274)
- Fixed an edge case where pending requests were not canceled properly (https://github.com/ray-project/ray/pull/47873)
- Removed deprecated API to set route_prefix per-deployment (https://github.com/ray-project/ray/pull/48223)

📖 Documentation:
- Added ProxyStatus model to reference docs (https://github.com/ray-project/ray/pull/48299)
- Added ApplicationStatus model to reference docs (https://github.com/ray-project/ray/pull/48220)

##### RLlib

💫 Enhancements:
- Upgrade to gymnasium==1.0.0 (support new API for vector env resets). ([#48443](https://github.com/ray-project/ray/pull/48443), [#45328](https://github.com/ray-project/ray/pull/45328))
- Add off-policy'ness metric to new API stack. ([#48227](https://github.com/ray-project/ray/pull/48227))
- Validate episodes before adding them to the buffer. ([#48083](https://github.com/ray-project/ray/pull/48083))

📖 Documentation:
- New example script for custom metrics on `EnvRunners` (using `MetricsLogger` API on the new stack). ([#47969](https://github.com/ray-project/ray/pull/47969))
- Do-over: New RLlib index page. ([#48285](https://github.com/ray-project/ray/pull/48285), [#48442](https://github.com/ray-project/ray/pull/48442))
- Do-over: Example script for AutoregressiveActionsRLM. ([#47972](https://github.com/ray-project/ray/pull/47972))

🏗 Architecture refactoring:
- New API stack on by default for PPO. ([#48284](https://github.com/ray-project/ray/pull/48284))
- Change config.fault_tolerance default behavior (from `recreate_failed_env_runners=False` to `True`). ([#48286](https://github.com/ray-project/ray/pull/48286))

🔨 Fixes:
- Various bug and CI fixes: [#47993](https://github.com/ray-project/ray/pull/47993), [#48450](https://github.com/ray-project/ray/pull/48450), [#48213](https://github.com/ray-project/ray/pull/48213)
- Cleanup `evaluation` folder ([#48493](https://github.com/ray-project/ray/pull/48493))

##### Ray Core

🎉 New Features:
- [CompiledGraphs] Support all reduce collective in aDAG ([#47621](https://github.com/ray-project/ray/pull/47621))
- [CompiledGraphs] Add visualization of compiled graphs ([#47958](https://github.com/ray-project/ray/pull/47958))

💫 Enhancement

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