Extend string parsing support for Date32 #5282
Conversation
gruuya
force-pushed
the
parse-timestamp-as-date
branch
from
fdfddd1
to
81ea97a
Compare
| "2020-9-8 01:02:03", | ||
| "2020-09-08 1:2:3", |
There was a problem hiding this comment.
It may make sense to support these two as well, though that isn't doable with the current TimestampParser.
There was a problem hiding this comment.
Something like this could be used to be more flexible with the date(time) support format, while also adhering to some form of input validation:
fn parse_date(string: &str) -> Option<NaiveDate> {
if string.len() > 10 {
let mut parts = string.splitn(2, ' ');
return match (parts.next(), parts.next()) {
(Some(date), Some(time)) if string_to_time(time).is_some() => parse_date(date),
_ => None,
};
};
There was a problem hiding this comment.
This would likely represent a major performance regression as formulated, but so long as we don't regress performance I have no major objections
There was a problem hiding this comment.
Yeah, let's go with the current approach, since it handles the majority of use cases anyway.
arrow-cast/src/cast.rs
Outdated
| @@ -7500,17 +7500,19 @@ mod tests { | |||
| assert!(c.is_valid(0)); // "2000-01-01" | |||
| assert_eq!(date_value, c.value(0)); | |||
|
|
|||
| assert!(c.is_valid(1)); // "2000-01-01" | |||
There was a problem hiding this comment.
This comment is incorrect
There was a problem hiding this comment.
Actually, since we trim away the time part, I think it's correct (I see 10957 as the value for both)?
There was a problem hiding this comment.
The value being parsed is still 2000-01-01T12:00:00 which is what this should read I think
There was a problem hiding this comment.
Oh I see; fixed now, thanks!
gruuya
force-pushed
the
parse-timestamp-as-date
branch
from
81ea97a
to
35c761b
Compare
This now includes the timestamp format besides the plain date format.
Which issue does this PR close?
Closes #5280.
Rationale for this change
PG supports casting a valid timestamp string into a date (by throwing away the time part).
What changes are included in this PR?
Fallback to parsing a datetime if the string length is too long for just a date.
Are there any user-facing changes?
None, except additional format support when casting to Date32.