You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@arrow.apache.org by "Wes McKinney (JIRA)" <ji...@apache.org> on 2019/08/01 22:34:00 UTC
[jira] [Updated] (ARROW-5878) [Python][C++] Parquet reader not
forward compatible for timestamps without timezone
[ https://issues.apache.org/jira/browse/ARROW-5878?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Wes McKinney updated ARROW-5878:
--------------------------------
Fix Version/s: (was: 1.0.0)
0.15.0
> [Python][C++] Parquet reader not forward compatible for timestamps without timezone
> -----------------------------------------------------------------------------------
>
> Key: ARROW-5878
> URL: https://issues.apache.org/jira/browse/ARROW-5878
> Project: Apache Arrow
> Issue Type: Bug
> Components: C++, Python
> Affects Versions: 0.14.0
> Reporter: Florian Jetter
> Assignee: Benjamin Kietzman
> Priority: Major
> Labels: parquet, pull-request-available
> Fix For: 0.14.1, 0.15.0
>
> Attachments: timezones_pyarrow_14.paquet
>
> Time Spent: 5h 20m
> Remaining Estimate: 0h
>
> Timestamps without timezone which are written by pyarrow 0.14.0 cannot be read anymore as timestamps by earlier versions. The timestamp is read as an integer when reading in with pyarrow 0.13.0
> Looking at the parquet schemas, it seems that the logical type cannot be understood by the older versions, see below.
> h4. File generation with pyarrow 0.14.0
> {code:java}
> import datetime
> import pyarrow.parquet as pq
> import pandas as pd
> df = pd.DataFrame(
> {
> "datetime64": pd.Series(["2018-01-01"], dtype="datetime64[ns]"),
> "datetime64_ts": pd.Series(
> [pd.Timestamp(datetime.datetime(2018, 1, 1), tz="Europe/Berlin")],
> dtype="datetime64[ns]",
> ),
> }
> )
> pq.write_table(pa.Table.from_pandas(df), "timezones_pyarrow_14.paquet")
> {code}
> h4. Reading with pyarrow 0.13.0
> {code:java}
> In [1]: import pyarrow.parquet as pq
> In [2]: import pyarrow as pa
> In [3]: with open("timezones_pyarrow_14.paquet", "rb") as fd:
> ...: table = pq.read_pandas(fd)
> ...:
> In [4]: table.to_pandas()
> Out[4]:
> datetime64 datetime64_ts
> 0 1514764800000000 2018-01-01 00:00:00+01:00
> In [5]: table.to_pandas().dtypes
> Out[5]:
> datetime64 int64
> datetime64_ts datetime64[ns, Europe/Berlin]
> dtype: object
> {code}
> h3. Parquet schema as seen by pyarrow versions:
> pyarrow 0.13.0 parquet schema
> {code:java}
> datetime64: INT64
> datetime64_ts: INT64 TIMESTAMP_MICROS
> {code}
> pyarrow 0.14.0 parquet schema
> {code:java}
> datetime64: INT64 Timestamp(isAdjustedToUTC=false, timeUnit=microseconds)
> datetime64_ts: INT64 Timestamp(isAdjustedToUTC=true, timeUnit=microseconds)
> {code}
--
This message was sent by Atlassian JIRA
(v7.6.14#76016)