joyhaldar opened a new issue, #18543:
URL: https://github.com/apache/iceberg/issues/18543

   ### Apache Iceberg version
   
   main (development)
   
   ### Query engine
   
   Spark
   
   ### Please describe the bug 🐞
   
   When reading an ORC file with the vectorized Spark reader, the `_row_id` 
metadata column is wrong. Every row gets the file's `first_row_id` instead of 
its own value.
   
   This happens because `VectorizedSparkOrcReaders.StructConverter` checks 
`idToConstant` before it checks for metadata columns, so `_row_id` is treated 
as a plain constant. Values stored in the file are ignored, and for rows with 
no stored value the row position is not added. `_last_updated_sequence_number` 
has the same problem.
   
   Example: a file with `first_row_id` = 100, where row 0 stores `_row_id` 555 
and row 1 stores null. The vectorized reader returns 100 for both. It should 
return 555 and 101.
   
   The row-based ORC reader does this correctly (`OrcValueReaders`, added in 
#15776 and #16534). The Parquet vectorized reader is also correct.
   
   Found while adding vectorized coverage to the format model TCK in #17610. 
#17635 has an earlier attempt at a fix.
   
   ### Willingness to contribute
   
   - [ ] I can contribute a fix for this bug independently
   - [x] I would be willing to contribute a fix for this bug with guidance from 
the Iceberg community
   - [ ] I cannot contribute a fix for this bug at this time


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