Simon Weiß created ARROW-17138: ---------------------------------- Summary: [Python] Converting data frame to Table with large nested column fails `Invalid Struct child array has length smaller than expected` Key: ARROW-17138 URL: https://issues.apache.org/jira/browse/ARROW-17138 Project: Apache Arrow Issue Type: Bug Components: Python Reporter: Simon Weiß
Hey, I have a data frame for which one column is a nested struct array. Converting it to a `pyarrow.Table` fails if the data frame gets too big. I could reproduce the bug with a minimal example with anonymized data that is roughly similar to mine. When I set, e.g., `N_ROWS=500_000`, or smaller, it is working fine. ```python import pandas as pd import pyarrow as pa N_ROWS = 800_000 item_record = { "someImportantAssets": [ { "square": "https://some.super.loooooooooong.link.com/withmany/lorem/upload/ipsum/stilllooooooooooonger/lorem/\{someparameter}/156fdjjf644984dfdfaera648/specificLink-i15348891" } ], "id": "i15348891", "title": "Some Long Item Title i15348891", } user_record = { "userId": "faa4648-4964drf-64648fafa648-4648falj", "data": [item_record for _ in range(24)], } df = pd.DataFrame([user_record for _ in range(N_ROWS)]) table = pa.Table.from_pandas(df) ``` ```python-traceback Traceback (most recent call last): table = pa.Table.from_pandas(df) File "pyarrow/table.pxi", line 1658, in pyarrow.lib.Table.from_pandas File "pyarrow/table.pxi", line 1702, in pyarrow.lib.Table.from_arrays File "pyarrow/table.pxi", line 1314, in pyarrow.lib.Table.validate File "pyarrow/error.pxi", line 99, in pyarrow.lib.check_status pyarrow.lib.ArrowInvalid: Column 1: In chunk 0: Invalid: List child array invalid: Invalid: Struct child array #1 invalid: Invalid: List child array invalid: Invalid: Struct child array #0 has length smaller than expected for struct array (13256071 < 13256072) ``` The length is always smaller than expected by 1. h2. Expected behavior: Run without errors or fail with a better error message. h2. System Info and Versions: Apple M1 Pro but also happened on amd64 Linux machine on AWS ``` arrow-cpp 7.0.0 py39h8a997f0_8_cpu conda-forge pyarrow 7.0.0 py39h3a11367_8_cpu conda-forge python 3.9.7 h54d631c_3_cpython conda-forge ``` I could also reproduce with `pyarrow 8.0.0` -- This message was sent by Atlassian Jira (v8.20.10#820010)