tlm365 commented on code in PR #14025: URL: https://github.com/apache/datafusion/pull/14025#discussion_r1905501646
########## datafusion/functions/src/unicode/reverse.rs: ########## @@ -116,14 +115,23 @@ pub fn reverse<T: OffsetSizeTrait>(args: &[ArrayRef]) -> Result<ArrayRef> { } } -fn reverse_impl<'a, T: OffsetSizeTrait, V: ArrayAccessor<Item = &'a str>>( +fn reverse_impl<'a, T: OffsetSizeTrait, V: StringArrayType<'a>>( string_array: V, ) -> Result<ArrayRef> { - let result = ArrayIter::new(string_array) - .map(|string| string.map(|string: &str| string.chars().rev().collect::<String>())) - .collect::<GenericStringArray<T>>(); + let mut builder: GenericStringBuilder<T> = + GenericStringBuilder::with_capacity(string_array.len(), 1024); Review Comment: > Yes, I think so Unfortunately, it's a bit slower than the current implementation. It allocates more mem than I expected, `string_array.get_array_memory_size()` = `16632` when `str_len = 1024`, and = `66168` when `str_len = 4096` 🤔 -- 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...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org