[IcebergIO] Groups rows by partition before writing

[ahmedabu98]

Adding a new sink code path that groups rows by partition before writing, making partitioned writes a lot more efficient and scalable.

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the IcebergIO sink by adding an optional feature to group rows by partition before writing them to the destination. This change is designed to optimize performance and reduce the creation of small files in partitioned Iceberg tables. The implementation introduces new transforms and utility classes to handle the grouping and writing logic, while also updating the existing API and test suites to support this new configuration.

Highlights

• Partitioned Write Optimization: Introduced a new sink code path that groups rows by partition before writing, which significantly improves efficiency and scalability for partitioned tables by reducing the number of small files.
• New Components: Added 'AssignDestinationsAndPartitions', 'WritePartitionedRowsToFiles', 'WriteToPartitions', and 'BeamRowWrapper' to support the new grouping logic.
• API Updates: Updated 'IcebergIO.WriteRows' and 'IcebergWriteSchemaTransformProvider' to include a 'groupByPartitions' configuration option.
• Test Coverage: Updated 'IcebergIOWriteTest' and 'IcebergWriteSchemaTransformProviderTest' to use parameterized tests, ensuring both grouped and non-grouped write paths are verified.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for GitHub and other Google products, sign up here.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩