[jira] [Created] (ORC-2223) [Java] RecordReaderImpl reads and parses each StripeFooter twice per stripe during scans

["yongzhi.shao (Jira)" <ji...@apache.org>]

yongzhi.shao created ORC-2223:
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             Summary: [Java] RecordReaderImpl reads and parses each StripeFooter twice per stripe during scans
                 Key: ORC-2223
                 URL: https://issues.apache.org/jira/browse/ORC-2223
             Project: ORC
          Issue Type: Improvement
            Reporter: yongzhi.shao


## Description

### Problem

When scanning an ORC file, `RecordReaderImpl.beginReadStripe()` already reads the `OrcProto.StripeFooter` for the current stripe (via `readStripeFooter(stripe)`). Immediately afterwards, `RecordReaderImpl.readStripe()` calls `StripePlanner.parseStripe(stripe, fileIncluded)`, which internally issues a **second, identical** `DataReader.readStripeFooter(stripe)` call for the same stripe.

This means every stripe during a scan performs a duplicate footer read (and protobuf re-parse) from the underlying `DataReader`. For remote/object stores or high-stripe-count files, this is a measurable, avoidable source of extra I/O and CPU — and it scales linearly with the number of stripes read.

### Root cause

`StripePlanner.parseStripe(StripeInformation, boolean[])` has a single entry point that unconditionally reads the footer itself, and `RecordReaderImpl` does not pass along the footer it already obtained in `beginReadStripe()`.

### Proposed fix

- Add an overloaded `StripePlanner.parseStripe(StripeInformation, boolean[], OrcProto.StripeFooter)` that accepts a footer already read by the caller. The existing two-argument `parseStripe` remains as a thin wrapper that reads the footer itself, preserving compatibility for other callers.
- In `RecordReaderImpl.readStripe()`, pass the footer already obtained in `beginReadStripe()` to the new overload, eliminating one `readStripeFooter` call per stripe.

### Scope / compatibility

- No change to the ORC file format or wire behavior.
- Public API is preserved (old `parseStripe` signature retained); no breaking changes.
- No C++ reader changes needed — this duplication is specific to the Java reader implementation.

### Testing

- New regression test `TestRecordReaderImpl.testNoDuplicateStripeFooterRead`: uses a Mockito spy on `DataReader` (with `clone()` stubbed to return the spy, since `RecordReaderImpl` clones the supplied reader) to assert **exactly one** `readStripeFooter` call per stripe, for both a plain scan and an SArg-filtered scan.
- Lowered read-percentage thresholds in `TestMinSeekSize`, `TestRowFilteringComplexTypesNulls`, and `TestRowFilteringIOSkip` to reflect the genuinely reduced bytes read per stripe.



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