dwsmith1983 opened a new issue, #5948: URL: https://github.com/apache/datafusion-comet/issues/5948
### What is the problem the feature request solves? Deletion-vector preparation in `native/core/src/execution/delta_dv.rs` fetches the data file's footer through `DFParquetMetadata` directly. It fills the shared metadata cache correctly, but it runs before the scan creates its instrumented reader, so the preparation footer and page-index I/O bypass the final scan's `scan_io_*` counters while the later open reports a cache hit. ### Describe the potential solution A preparation hook in the shared scan builder, or a shared metadata helper with the same metrics owner, so preparation and normal reads share one place for metadata policy and instrumentation. The preparation accounting must land in the final scan's counters; a separate factory whose counters are discarded keeps the gap. Cold-cache and warm-cache tests verify that preparation I/O is counted, the footer is reused, and warm opens avoid storage reads, while keeping the INT96 stamping on cached metadata. ### Additional context Raised in the #5365 review (item 7); filed as a follow-up. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
