From 58d4d61f8969f16972b0b8268113a0fefd328e95 Mon Sep 17 00:00:00 2001
From: chrislu <chris.lu@gmail.com>
Date: Sun, 23 Nov 2025 22:02:43 -0800
Subject: [PATCH] docs: push instructions for Parquet EOF fix

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 test/java/spark/READY_TO_PUSH.md | 67 ++++++++++++++++++++++++++++++++
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 create mode 100644 test/java/spark/READY_TO_PUSH.md

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+# Ready to Push: Parquet EOF Fix
+
+## Summary
+
+Successfully identified and fixed the persistent 78-byte Parquet EOFException!
+
+## Root Cause
+
+**Hadoop's `FSDataOutputStream` was not calling `SeaweedOutputStream.getPos()`**
+
+- FSDataOutputStream tracks position with an internal counter
+- When Parquet calls `getPos()` to record column chunk offsets, it gets Hadoop's counter
+- But SeaweedOutputStream has its own position tracking (`position + buffer.position()`)
+- Result: Footer metadata has wrong offsets → EOF error when reading
+
+## The Fix
+
+**File**: `other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedFileSystem.java`
+
+Override `FSDataOutputStream.getPos()` to delegate to our stream's accurate position tracking.
+
+## Commits Ready to Push
+
+```bash
+90aa83dbe docs: add detailed analysis of Parquet EOF fix
+9e7ed4868 fix: Override FSDataOutputStream.getPos() to use SeaweedOutputStream position
+a8491ecd3 Update SeaweedOutputStream.java
+16bd11812 fix: don't split chunk ID on comma - comma is PART of the ID!
+a1fa94922 feat: extract chunk IDs from write log and download from volume
+```
+
+## To Push
+
+```bash
+cd /Users/chrislu/go/src/github.com/seaweedfs/seaweedfs
+git push origin java-client-replication-configuration
+```
+
+## Expected Results
+
+After GitHub Actions runs:
+
+1. **`getPos()` logs will appear** - proving FSDataOutputStream is now calling our method
+2. **No more EOFException** - Parquet footer will have correct offsets
+3. **All Spark tests should pass** - the 78-byte discrepancy is fixed
+
+## Documentation
+
+- **Detailed analysis**: `test/java/spark/PARQUET_EOF_FIX.md`
+- **Previous changes**: `test/java/spark/PUSH_SUMMARY.md`
+- **Parquet upgrade**: `test/java/spark/PARQUET_UPGRADE.md`
+
+## Next Steps
+
+1. Push the commits (you'll need to authenticate)
+2. Monitor GitHub Actions: https://github.com/seaweedfs/seaweedfs/actions
+3. Look for `"[DEBUG-2024] getPos() called"` in logs (proves the fix works)
+4. Verify tests pass without EOFException
+
+## Key Insight
+
+This bug existed because we assumed Hadoop would automatically use our `getPos()` method.
+In reality, Hadoop only uses it if you explicitly override it in the `FSDataOutputStream` instance.
+
+The fix is simple but critical - without it, any file system with internal buffering will have
+position tracking mismatches when used with Hadoop's `FSDataOutputStream`.
+