fix: [HUDI-8371] Fix Column Stats Record Key using full partition path

[linliu-code]

Describe the issue this Pull Request addresses

When column stats index is enabled on a table that already has the FILES metadata partition initialized listAllPartitionsFromMDT is used to bootstrap the column stats partition. The method was passing the absolute partition path (e.g., hdfs://host/table/partition1) as the first argument to DirectoryInfo instead of the relative path (e.g., partition1). This caused the column stats index to be keyed on wrong paths, resulting in empty or incorrect column stats lookups during data skipping.

Summary and Changelog

Fix: In HoodieBackedTableMetadataWriter.listAllPartitionsFromMDT, compute the relative partition path using FSUtils.getRelativePartitionPath(basePath, absolutePath) before constructing each DirectoryInfo, instead of passing the absolute map key directly.

Changes:

HoodieBackedTableMetadataWriter.java: Fixed listAllPartitionsFromMDT to use relative partition paths when constructing DirectoryInfo entries.

Impact

No public API or config changes. Users who enable column stats on an existing table (i.e., FILES partition already initialized but column stats was not) will now get a correctly populated column stats index, enabling data skipping to work as expected instead of silently returning no stats.

Risk Level

Low

Documentation Update

Contributor's checklist

• Read through contributor's guide
• Enough context is provided in the sections above
• Adequate tests were added if applicable

[hudi-bot]

CI report:

• 53838d4 Azure: SUCCESS

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