avantgardnerio commented on code in PR #2984: URL: https://github.com/apache/arrow-datafusion/pull/2984#discussion_r933644641
########## datafusion/sql/src/interval.rs: ########## @@ -0,0 +1,214 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Interval parsing logic +use datafusion_common::{DataFusionError, Result, ScalarValue}; +use std::str::FromStr; + +const SECONDS_PER_HOUR: f32 = 3_600_f32; +const MILLIS_PER_SECOND: f32 = 1_000_f32; + +/// Parses a string with an interval like `'0.5 MONTH'` to an +/// appropriately typed [`ScalarValue`] +pub(crate) fn parse_interval(leading_field: &str, value: &str) -> Result<ScalarValue> { + // We are storing parts as integers, it's why we need to align parts fractional + // INTERVAL '0.5 MONTH' = 15 days, INTERVAL '1.5 MONTH' = 1 month 15 days + // INTERVAL '0.5 DAY' = 12 hours, INTERVAL '1.5 DAY' = 1 day 12 hours + let align_interval_parts = + |month_part: f32, mut day_part: f32, mut milles_part: f32| -> (i32, i32, f32) { + // Convert fractional month to days, It's not supported by Arrow types, but anyway + day_part += (month_part - (month_part as i32) as f32) * 30_f32; + + // Convert fractional days to hours + milles_part += (day_part - ((day_part as i32) as f32)) + * 24_f32 + * SECONDS_PER_HOUR + * MILLIS_PER_SECOND; + + (month_part as i32, day_part as i32, milles_part) + }; + + let calculate_from_part = + |interval_period_str: &str, interval_type: &str| -> Result<(i32, i32, f32)> { + // @todo It's better to use Decimal in order to protect rounding errors + // Wait https://github.com/apache/arrow/pull/9232 + let interval_period = match f32::from_str(interval_period_str) { + Ok(n) => n, + Err(_) => { + return Err(DataFusionError::NotImplemented(format!( + "Unsupported Interval Expression with value {:?}", + value + ))); + } + }; + + if interval_period > (i32::MAX as f32) { + return Err(DataFusionError::NotImplemented(format!( + "Interval field value out of range: {:?}", + value + ))); + } + + match interval_type.to_lowercase().as_str() { + "year" => Ok(align_interval_parts(interval_period * 12_f32, 0.0, 0.0)), + "month" => Ok(align_interval_parts(interval_period, 0.0, 0.0)), + "day" | "days" => Ok(align_interval_parts(0.0, interval_period, 0.0)), + "hour" | "hours" => { + Ok((0, 0, interval_period * SECONDS_PER_HOUR * MILLIS_PER_SECOND)) + } + "minutes" | "minute" => { + Ok((0, 0, interval_period * 60_f32 * MILLIS_PER_SECOND)) + } + "seconds" | "second" => Ok((0, 0, interval_period * MILLIS_PER_SECOND)), + "milliseconds" | "millisecond" => Ok((0, 0, interval_period)), + _ => Err(DataFusionError::NotImplemented(format!( + "Invalid input syntax for type interval: {:?}", + value + ))), + } + }; + + let mut result_month: i64 = 0; + let mut result_days: i64 = 0; + let mut result_millis: i64 = 0; + + let mut parts = value.split_whitespace(); + + loop { + let interval_period_str = parts.next(); + if interval_period_str.is_none() { + break; + } + + let unit = parts.next().unwrap_or(leading_field); + + let (diff_month, diff_days, diff_millis) = + calculate_from_part(interval_period_str.unwrap(), unit)?; + + result_month += diff_month as i64; + + if result_month > (i32::MAX as i64) { + return Err(DataFusionError::NotImplemented(format!( + "Interval field value out of range: {:?}", + value + ))); + } + + result_days += diff_days as i64; + + if result_days > (i32::MAX as i64) { + return Err(DataFusionError::NotImplemented(format!( + "Interval field value out of range: {:?}", + value + ))); + } + + result_millis += diff_millis as i64; + + if result_millis > (i32::MAX as i64) { + return Err(DataFusionError::NotImplemented(format!( + "Interval field value out of range: {:?}", + value + ))); + } + } + + // 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 + // It's why we there are 3 different interval types in Arrow + if result_month != 0 && (result_days != 0 || result_millis != 0) { + let result: i128 = ((result_month as i128) << 96) + | ((result_days as i128) << 64) + // IntervalMonthDayNano uses nanos, but IntervalDayTime uses milles + | ((result_millis * 1_000_000_i64) as i128); + + return Ok(ScalarValue::IntervalMonthDayNano(Some(result))); + } + + // Month interval + if result_month != 0 { + return Ok(ScalarValue::IntervalYearMonth(Some(result_month as i32))); + } + + let result: i64 = (result_days << 32) | result_millis; + Ok(ScalarValue::IntervalDayTime(Some(result))) +} + +#[cfg(test)] +mod test { + use crate::assert_contains; + + use super::*; + + #[test] + fn test_parse_ym() { + assert_eq!( + parse_interval("months", "1 month").unwrap(), + ScalarValue::new_interval_ym(0, 1) + ); + + assert_eq!( + parse_interval("months", "2 month").unwrap(), + ScalarValue::new_interval_ym(0, 2) + ); + + assert_eq!( + parse_interval("months", "3 year 1 month").unwrap(), + ScalarValue::new_interval_ym(3, 1) + ); + + assert_contains!( + parse_interval("months", "1 years 1 month") + .unwrap_err() + .to_string(), + r#"Invalid input syntax for type interval: "1 years 1 month""# + ); + } + + #[test] + fn test_dt() { + assert_eq!( + parse_interval("months", "5 days").unwrap(), + ScalarValue::new_interval_dt(5, 0) + ); + + assert_eq!( + parse_interval("months", "7 days 3 hours").unwrap(), + ScalarValue::new_interval_dt( + 7, + (3.0 * SECONDS_PER_HOUR * MILLIS_PER_SECOND) as i32 + ) + ); + + assert_eq!( + parse_interval("months", "7 days 5 minutes").unwrap(), + ScalarValue::new_interval_dt(7, (5.0 * 60.0 * MILLIS_PER_SECOND) as i32) + ); + } + + #[test] + // TODO file a ticket to track Review Comment: I think I found the C impl, and I think `parse_interval()` looks correct https://github.com/apache/arrow/blob/02c8598d264c839a5b5cf3109bfd406f3b8a6ba5/cpp/src/arrow/type.h#L1475 I can make a PR to fix shortly if we're sure this is the correct format. It would be good to have an integration test between C & Rust. Do we have anything like that now? -- 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: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
