emkornfield commented on code in PR #461: URL: https://github.com/apache/parquet-format/pull/461#discussion_r1854915859
########## VariantEncoding.md: ########## @@ -39,13 +39,41 @@ Another motivation for the representation is that (aside from metadata) each nes For example, in a Variant containing an Array of Variant values, the representation of an inner Variant value, when paired with the metadata of the full variant, is itself a valid Variant. This document describes the Variant Binary Encoding scheme. -[VariantShredding.md](VariantShredding.md) describes the details of the Variant shredding scheme. +The [Variant Shredding specification](VariantShredding.md) describes the details of shredding Variant values as typed Parquet columns. + +## Variant in Parquet -# Variant in Parquet A Variant value in Parquet is represented by a group with 2 fields, named `value` and `metadata`. -Both fields `value` and `metadata` are of type `binary`, and cannot be `null`. -# Metadata encoding +* The Variant group must be annotated with the `VARIANT` logical type. +* Both fields `value` and `metadata` must be of type `binary` (called `BYTE_ARRAY` in the Parquet thrift definition). +* The `metadata` field is required and must be a valid Variant metadata, as defined below. +* The `value` field is required for unshredded Variant values. Review Comment: ```suggestion * The `value` must be annotated either as required (no shredding) or optional (if shredding might happen) ``` This might address the confusion on @wgtmac comment below (and we eliminate the other bullet points below, if we inline the link. -- 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]
