Hi, For now, There are only two types of IntervalUnit inside Arrow:
- YearMonth - month stored as int32 - DayTime - days as int32 and time in milliseconds as in32. Total (64 bites) Since DF is using Arrow, It’s not possible to store “Complex” intervals such 1 MONTH 1 DAY 1 HOUR. I think, the best way to understand the problem will be to read a comment from DF codebase: https://github.com/apache/arrow/blob/bca7d2fe84ccd8fc1129cb4d85448eb0779c52c3/rust/datafusion/src/sql/planner.rs#L1148 // Interval is tricky thing // 1 day is not 24 hours because timezones, 1 year != 365/364! 30 days != 1 month // The true way to store and calculate intervals is to store it as it defined // Due the fact that Arrow supports only two types YearMonth (month) and DayTime (day, time) // It's not possible to store complex intervals // It's possible to do select (NOW() + INTERVAL '1 year') + INTERVAL '1 day'; as workaround if result_month != 0 && (result_days != 0 || result_millis != 0) { return Err(DataFusionError::NotImplemented(format!( "DF does not support intervals that have both a Year/Month part as well as Days/Hours/Mins/Seconds: {:?}. Hint: try breaking the interval into two parts, one with Year/Month and the other with Days/Hours/Mins/Seconds - e.g. (NOW() + INTERVAL '1 year') + INTERVAL '1 day'", value ))); } I prepared a PR https://github.com/apache/arrow/pull/9516/files <https://github.com/apache/arrow/pull/9516/files> that introduce a new type for IntervalUnit called Complex, that store both YearMonth and DayTime to support complex interval. I didn’t find any page/documentation on how to do RFC in Arrow protocol, so can anyone point me to it or PR with email will be enough? Thanks.
