Optimize to_timestamp (with format) (apache#9090) (apache#9833)

Eliminate duplicate parsing of the input and format strings in some cases

Co-authored-by: Vojtech Toman <[email protected]>

datafusion/functions/src/datetime/common.rs

@@ -22,8 +22,9 @@ use arrow::array::{
 };
 use arrow::compute::kernels::cast_utils::string_to_timestamp_nanos;
 use arrow::datatypes::DataType;
+use chrono::format::{parse, Parsed, StrftimeItems};
 use chrono::LocalResult::Single;
-use chrono::{DateTime, NaiveDateTime, TimeZone, Utc};
+use chrono::{DateTime, TimeZone, Utc};
 use itertools::Either;
 
 use datafusion_common::cast::as_generic_string_array;
@@ -84,12 +85,15 @@ pub(crate) fn string_to_datetime_formatted<T: TimeZone>(
         ))
     };
 
+    let mut parsed = Parsed::new();
+    parse(&mut parsed, s, StrftimeItems::new(format)).map_err(|e| err(&e.to_string()))?;
+
     // attempt to parse the string assuming it has a timezone
-    let dt = DateTime::parse_from_str(s, format);
+    let dt = parsed.to_datetime();
 
     if let Err(e) = &dt {
         // no timezone or other failure, try without a timezone
-        let ndt = NaiveDateTime::parse_from_str(s, format);
+        let ndt = parsed.to_naive_datetime_with_offset(0);
         if let Err(e) = &ndt {
             return Err(err(&e.to_string()));
         }