Fokko commented on issue #6647:
URL: https://github.com/apache/iceberg/issues/6647#issuecomment-1436091339
@rdblue that's correct.
I took a shortcut and get the schema from the metadata. That should still be
the preferred way because it is probably faster (Pydantic without any GIL just
going through the JSON document).
However, the fields in Parquet also have metadata, and those contain the
`field_id`:
```python
➜ Desktop python3
Python 3.10.10 (main, Feb 8 2023, 05:34:50) [Clang 14.0.0
(clang-1400.0.29.202)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from pyarrow.fs import LocalFileSystem
>>> import pyarrow.parquet as pq
>>>
>>> fs = LocalFileSystem()
>>>
>>> path =
"/Users/fokkodriesprong/Desktop/00003-4-5e18fe8b-532b-42ec-bdb9-0c7ba7078155-00001.parquet"
>>>
>>> with fs.open_input_file(path) as fout:
... parquet_schema = pq.read_schema(fout)
...
>>>
>>> parquet_schema
VendorID: int64
-- field metadata --
PARQUET:field_id: '1'
tpep_pickup_datetime: timestamp[us, tz=UTC]
-- field metadata --
PARQUET:field_id: '2'
tpep_dropoff_datetime: timestamp[us, tz=UTC]
-- field metadata --
PARQUET:field_id: '3'
passenger_count: double
-- field metadata --
PARQUET:field_id: '4'
trip_distance: double
-- field metadata --
PARQUET:field_id: '5'
RatecodeID: double
-- field metadata --
PARQUET:field_id: '6'
store_and_fwd_flag: string
-- field metadata --
PARQUET:field_id: '7'
PULocationID: int64
-- field metadata --
PARQUET:field_id: '8'
DOLocationID: int64
-- field metadata --
PARQUET:field_id: '9'
payment_type: int64
-- field metadata --
PARQUET:field_id: '10'
fare_amount: double
-- field metadata --
PARQUET:field_id: '11'
extra: double
-- field metadata --
PARQUET:field_id: '12'
mta_tax: double
-- field metadata --
PARQUET:field_id: '13'
tip_amount: double
-- field metadata --
PARQUET:field_id: '14'
tolls_amount: double
-- field metadata --
PARQUET:field_id: '15'
improvement_surcharge: double
-- field metadata --
PARQUET:field_id: '16'
total_amount: double
-- field metadata --
PARQUET:field_id: '17'
congestion_surcharge: double
-- field metadata --
PARQUET:field_id: '18'
airport_fee: double
-- field metadata --
PARQUET:field_id: '19'
-- schema metadata --
iceberg.schema: '{"type":"struct","schema-id":0,"fields":[{"id":1,"name":' +
1236
```
@amogh-jahagirdar We could implement a visitor to convert this Arrow schema
back to an Iceberg one with the correct IDs.
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