feat(io): add io_uring backend

[LHT129]

What

This PR adds an optional io_uring IO backend for Linux systems with liburing available.

Changes include:

• Add UringIO, UringIOContext, and UringIOParameter.
• Add CMake detection for liburing via ENABLE_LIBURING, HAVE_LIBURING, and NO_LIBURING.
• Wire uring_io into IO parameter parsing, IO headers, flatten/bucket/graph datacell factories, and RabitQ split IO type validation.
• Fall back from uring_io to buffer_io with a one-time warning when liburing is unavailable.
• Add UringIO and UringIOParameter unit tests.

Both filtered test runs passed with 4 test cases and 16805 assertions.

Closes #1533

[mergify]

Merge Protections

🟢 All 3 merge protections satisfied — ready to merge.

Show 3 satisfied protections

🟢 Require kind label

• label~=^kind/

🟢 Require version label

• label~=^version/

🟢 Require linked issue for feature/bug PRs

• body~=(?im)(?:^|[\s\-\*])(?:close[sd]?|fix(?:e[sd])?|resolve[sd]?)\s*:?\s+(?:#\d+|[\w.\-]+/[\w.\-]+#\d+|https?://github\.com/[\w.\-]+/[\w.\-]+/issues/\d+)

[gemini-code-assist]

Code Review

This pull request introduces support for the io_uring asynchronous I/O framework (uring_io) as an alternative I/O backend. It adds CMake configuration options to detect and link liburing, integrates the new I/O type into various datacell factories, and implements the UringIO class along with its parameters and unit tests. The feedback highlights several critical areas for improvement: a potential file descriptor and file leak in the UringIO constructor if initialization fails, a performance bottleneck caused by mixing O_DIRECT reads with buffered writes (requiring frequent fsync calls), error-prone manual resource management in MultiReadImpl that should leverage RAII, and the use of preprocessor macros for fallback types which should be replaced with clean C++ type aliases.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[Copilot]

Pull request overview

Adds an optional io_uring-based I/O backend for Linux builds, integrating it into IO parameter parsing and the major datacell factories, with CMake-based detection/linking of liburing and fallback behavior when unavailable.

Changes:

• Introduces UringIO, UringIOContext, and UringIOParameter (plus unit tests) under HAVE_LIBURING.
• Extends IO type parsing/dispatch and datacell factories to recognize "uring_io", with fallback-to-buffer behavior when liburing is missing.
• Adds a build option (ENABLE_LIBURING) and CMake detection/linking for liburing.

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/io/uring_io.h	Declares UringIO and provides a no-liburing alias fallback.
src/io/uring_io.cpp	Implements UringIO operations including multi-read using io_uring.
src/io/uring_io_test.cpp	Adds unit tests for UringIO behavior.
src/io/uring_io_parameter.h	Defines UringIOParameter with fallback behavior when liburing is absent.
src/io/uring_io_parameter.cpp	Implements JSON (de)serialization for UringIOParameter.
src/io/uring_io_parameter_test.cpp	Adds a unit test for UringIOParameter JSON round-tripping.
src/io/uring_io_context.h	Adds an io_uring context wrapper and pool type.
src/io/io_parameter.cpp	Adds "uring_io" parsing with one-time fallback warning when liburing is unavailable.
src/io/io_headers.h	Wires uring_io.h into the common IO header set.
src/io/CMakeLists.txt	Adds new sources and links liburing when available.
src/inner_string_params.h	Adds the "uring_io" IO type string constant.
src/datacell/rabitq_split_datacell.h	Allows "uring_io" as a known IO type for validation.
src/datacell/graph_interface.cpp	Enables graph datacell instantiation with UringIO.
src/datacell/flatten_interface.cpp	Enables flatten datacell instantiation with UringIO.
src/datacell/bucket_interface.cpp	Enables bucket datacell instantiation with UringIO.
cmake/VSAGSystemDeps.cmake	Detects liburing and defines HAVE_LIBURING/NO_LIBURING.
cmake/VSAGOptions.cmake	Adds ENABLE_LIBURING option.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 17 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 17 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 17 changed files in this pull request and generated 2 comments.

[vsag-bot]

/label S-waiting-on-review
/waiting-on reviewer
/request-review @jiaweizone
/request-review @wxyucs
/request-review @inabao

[Copilot]

Pull request overview

Copilot reviewed 17 out of 17 changed files in this pull request and generated 5 comments.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 17 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 3 comments.