felipecrv commented on code in PR #48002: URL: https://github.com/apache/arrow/pull/48002#discussion_r2550422505
########## docs/source/format/CanonicalExtensions.rst: ########## @@ -544,6 +544,33 @@ Primitive Type Mappings | UUID extension type | UUID | +----------------------+------------------------+ +.. _timestamp_with_offset_extension: + +Timestamp With Offset +============= +This type represents a timestamp column that stores potentially different timezone offsets per value. The timestamp is stored in UTC alongside the original timezone offset in minutes. +This extension type is intended to be compatible with ANSI SQL's ``TIMESTAMP WITH TIME ZONE``, which is supported by multiple database engines. + +* Extension name: ``arrow.timestamp_with_offset``. + +* The storage type of the extension is a ``Struct`` with 2 fields, in order: + + * ``timestamp``: a non-nullable ``Timestamp(time_unit, "UTC")``, where ``time_unit`` is any Arrow ``TimeUnit`` (s, ms, us or ns). + + * ``offset_minutes``: a non-nullable signed 16-bit integer (``Int16``) representing the offset in minutes from the UTC timezone. Negative offsets represent time zones west of UTC, while positive offsets represent east. Offsets range from -779 (-12:59) to +780 (+13:00). + +* Extension type parameters: + + This type does not have any parameters. + +* Description of the serialization: + + Extension metadata is an empty string. + +.. note:: + + It is also *permissible* for the ``offset_minutes`` field to be dictionary-encoded or run-end-encoded. Review Comment: In the interest of brevity of the spec, I advised @serramatutu to not have recommendations here. I would assume anyone deciding to dictionary-encode an int16 array is considering the gains (or not) that they would have from that encoding. We are allowing but not recommending complicated encoding of an already compact 16-bit-valued array. -- 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]
