Diego Argueta created ARROW-2026:
------------------------------------
Summary: Timestamps saved as int64 even if
use_deprecated_int96_timestamps=True
Key: ARROW-2026
URL: https://issues.apache.org/jira/browse/ARROW-2026
Project: Apache Arrow
Issue Type: Bug
Components: Python
Affects Versions: 0.8.0
Environment: OS: Mac OS X 10.13.2
Python: 3.6.4
PyArrow: 0.8.0
Reporter: Diego Argueta
When writing to a Parquet file, if `use_deprecated_int96_timestamps` is True,
timestamps are only written as 96-bit integers if the timestamp has nanosecond
resolution. This is a problem because Amazon Redshift timestamps only have
microsecond resolution but requires 96-bit format in Parquet files.
I'd expect the use_deprecated_int96_timestamps flag to cause _all_ timestamps
to be written as 96 bits, regardless of resolution. If this is a deliberate
design decision, it'd be immensely helpful if it were explicitly documented as
part of the argument.
To reproduce:
1. Create a table with a timestamp having microsecond or millisecond
resolution, and save it to a Parquet file. Be sure to set
`use_deprecated_int96_timestamps` to True.
{code:java}
import datetime
import pyarrow
from pyarrow import parquet
schema = pyarrow.schema([
pyarrow.field('last_updated', pyarrow.timestamp('us')),
])
data = [
pyarrow.array([datetime.datetime.now()], pyarrow.timestamp('us')),
]
table = pyarrow.Table.from_arrays(data, ['last_updated'])
with open('test_file.parquet', 'wb') as fdesc:
parquet.write_table(table, fdesc,
use_deprecated_int96_timestamps=True)
{code}
2. Inspect the file. I used parquet-tools:
{noformat}
dak@tux ~ $ parquet-tools meta test_file.parquet
file: file:/Users/dak/test_file.parquet
creator: parquet-cpp version 1.3.2-SNAPSHOT
file schema: schema
--------------------------------------------------------------------------------
last_updated: OPTIONAL INT64 O:TIMESTAMP_MICROS R:0 D:1
row group 1: RC:1 TS:76 OFFSET:4
--------------------------------------------------------------------------------
last_updated: INT64 SNAPPY DO:4 FPO:28 SZ:76/72/0.95 VC:1
ENC:PLAIN,PLAIN_DICTIONARY,RLE{noformat}
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
