stevenzwu commented on code in PR #16425: URL: https://github.com/apache/iceberg/pull/16425#discussion_r4517802302
########## format/spec.md: ########## @@ -1801,6 +1804,44 @@ If a delete column in an equality delete file is later dropped from the table, i Manifests hold the same statistics for delete files and data files. For delete files, the metrics describe the values that were deleted. +### Column Files + +Starting in v4, a data file or v4 leaf manifest may store fields in column files listed in [`column_files`](#column-file-fields). A column file can use any supported Iceberg file format and must have rows that align with the file it modifies. + +A column file stores the fields listed in its `field_ids`, each as a whole, including all of its nested fields. Each ID must identify a field in the schema of the file it modifies, which is the table schema for a data file and the tracked file schema for a leaf manifest, or a row lineage field required by [Writing Column Files](#writing-column-files). Fields nested within a list or map must not be listed in `field_ids`. + +#### Writing Column Files + +The rules below apply to column files of data files. Rules for writing column files of leaf manifests are not defined here. Review Comment: just `file` seems a little vague to me. I found `base file` reflects our column overlay approach more accurately. there is a special base file that don't have `field_ids` . Let's also see if others have any feedback on this. -- 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]
