wgtmac commented on code in PR #1867: URL: https://github.com/apache/orc/pull/1867#discussion_r1547139402
########## site/_docs/types.md: ########## @@ -69,7 +69,9 @@ create table Foobar ( ORC includes two different forms of timestamps from the SQL world: -* **Timestamp** is a date and time without a time zone, which does not change based on the time zone of the reader. +* **Timestamp** is a date and time without a time zone, where the timestamp value is stored in the writer timezone +encoded at the stripe level, if present. ORC readers will read this value back into the reader's timezone. Usually +both writer and reader timezones default to UTC, however older ORC files may contain non-UTC writer timezones Review Comment: > Usually both writer and reader timezones default to UTC, however older ORC files may contain non-UTC writer timezones` The main purpose of this timestamp type is to restore the wall clock time regardless of the reader time zone. IIRC, the Java implementation uses the writer local time zone instead of UTC. Due to insufficient C++ time zone utility support in earlier days, the C++ code by default uses UTC as the writer time zone to avoid complexity. -- 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]
