[ARROW-5888] [Python][C++] Add metadata to store Arrow time zones in Parquet file metadata

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.15.0
• Component/s: C++, Python
• Labels: parquet pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/22302
• Assignee: Wes McKinney
• Reporter: Florian Jetter
• Created: 09/Jul/19 15:04
• Updated: 11/Jan/23 07:43
• Resolved: 21/Aug/19 13:39

Description

The timezone is not roundtrip safe for timezones other than UTC when storing to parquet. Expected behavior would be that the timezone is properly reconstructed

schema = pa.schema(
    [
        pa.field("no_tz", pa.timestamp('us')),
        pa.field("no_tz", pa.timestamp('us', tz="UTC")),
        pa.field("no_tz", pa.timestamp('us', tz="Europe/Berlin")),
]
)
buf = pa.BufferOutputStream()
pq.write_metadata(
    schema,
    buf,
    coerce_timestamps="us"
)

pq_bytes = buf.getvalue().to_pybytes()
reader = pa.BufferReader(pq_bytes)
parquet_file = pq.ParquetFile(reader)
parquet_file.schema.to_arrow_schema()
# Output:
# no_tz: timestamp[us]
# utc: timestamp[us, tz=UTC]
# europe: timestamp[us, tz=UTC]

Issue Links

• links to: GitHub Pull Request #5138