danielcweeks commented on code in PR #17918: URL: https://github.com/apache/iceberg/pull/17918#discussion_r3908757195
########## format/spec.md: ########## @@ -321,6 +323,32 @@ For `geography` types, an additional parameter A specifies an algorithm for inte * `andoyer`: Thomas, Paul D. Mathematical models for navigation systems. US Naval Oceanographic Office, 1965. * `karney`: [Karney, Charles FF. "Algorithms for geodesics." Journal of Geodesy 87 (2013): 43-55](https://link.springer.com/content/pdf/10.1007/s00190-012-0578-z.pdf), and [GeographicLib](https://geographiclib.sourceforge.io/) +#### File Type + +A **`file`** represents a range of bytes that may be stored inline in the value or in an external file. The `file` type and its value semantics are defined by the `FILE` logical type in the [Parquet project](https://github.com/apache/parquet-format/pull/585). + +A `file` value has a fixed set of sub-fields. The sub-fields are implicit: they are not represented in the Iceberg schema and cannot be added, removed, reordered, or promoted. Their names, types, and field-ID offsets are: + +| Sub-field | ID offset | Type | +|----------------|-----------|----------| +| `uri` | +1 | `string` | +| `offset` | +2 | `long` | +| `size` | +3 | `long` | +| `content_type` | +4 | `string` | +| `checksum` | +5 | `string` | +| `inline` | +6 | `binary` | + +Adding a `file` field reserves the root field's ID plus six consecutive IDs for its sub-fields, assigned by the offsets above. Writers must advance `last-column-id` past all seven IDs and must not assign these IDs to any other field. + +A `file` value has no whole-value statistics. Each sub-field's statistics are tracked in `content_stats` under the sub-field's reserved ID, as for any field of the sub-field's type. Writers should produce statistics for `uri`, `content_type`, and `inline` fields; other fields may be omitted. Review Comment: The inline value is truncated per the `bytes` type. We felt it was useful to determine if there are inline or out-of-line values. You could omit the lower/upper bounds, but the value counts/nulls are meaningful. Size and offset may be less important overall (offset is largely useless). -- 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]
