[ARROW-14231] [C++] Can't cast from timestamp to utf8 when saving CSV

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.0.0
• Component/s: C++
• Labels: kernel pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/29811
• Assignee: David Li
• Reporter: Nicola Crane
• Created: 05/Oct/21 15:54
• Updated: 11/Jan/23 08:38
• Resolved: 09/Nov/21 17:28

Description

The R code below creates a simple data frame containing a datetime (timestamp) object, but when I try to save this to disk I get an "unsupported cast" error.

library(arrow)
df <- tibble::tibble(datetime = as.POSIXct(c("2020-07-20 16:20", NA), tz = "UTC"))
write_csv_arrow(df, "df.csv")
# Error: NotImplemented: Unsupported cast from timestamp[us, tz=UTC] to utf8 using function cast_string
# /home/nic2/arrow/cpp/src/arrow/compute/function.cc:215  DispatchBest(&inputs)
# /home/nic2/arrow/cpp/src/arrow/compute/cast.cc:229  Cast(Datum(value), to_type, options, ctx)
# /home/nic2/arrow/cpp/src/arrow/csv/writer.cc:101  compute::Cast(data, utf8(), compute::CastOptions(), &ctx)
# /home/nic2/arrow/cpp/src/arrow/csv/writer.cc:395  column_populators_[col]->UpdateRowLengths(*batch.column(col), offsets_.data())
# /home/nic2/arrow/cpp/src/arrow/csv/writer.cc:324  TranslateMinimalBatch(*batch)
# /home/nic2/arrow/cpp/src/arrow/csv/writer.cc:434  writer->WriteTable(table)

Issue Links

• is duplicated by: ARROW-15105 [R] unsupported timestamp cast in CSV with tz element
• is related to: ARROW-14643 [C++] Support cast from timestamp[UTC] to string on Windows
• is related to: ARROW-13625 [C++][CSV] Timestamp parsing should accept any valid ISO 8601 without requiring custom parse strings
• relates to: ARROW-12540 [C++] Implement cast from date32[day] to utf8
• links to: GitHub Pull Request #11328