[jira] [Updated] (ARROW-17828) [C++][Python] Large strings cause ArrowInvalid: offset overflow while concatenating arrays

["David Li (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-17828?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

David Li updated ARROW-17828:
-----------------------------
    Summary: [C++][Python] Large strings cause ArrowInvalid: offset overflow while concatenating arrays  (was: Large strings cause ArrowInvalid: offset overflow while concatenating arrays)

> [C++][Python] Large strings cause ArrowInvalid: offset overflow while concatenating arrays
> ------------------------------------------------------------------------------------------
>
>                 Key: ARROW-17828
>                 URL: https://issues.apache.org/jira/browse/ARROW-17828
>             Project: Apache Arrow
>          Issue Type: Bug
>          Components: Python
>    Affects Versions: 9.0.0
>            Reporter: Ben Epstein
>            Priority: Major
>
> When working with medium-sized datasets that have very long strings, arrow fails when trying to operate on the strings. The root is the `combine_chunks` function.
> Here is a minimally reproducible example
> {code:java}
> import numpy as np
> import pyarrow as pa
> # Create a large string
> x = str(np.random.randint(low=0,high=1000, size=(30000,)).tolist())
> t = pa.chunked_array([x]*20_000)
> # Combine the chunks into large string array - fails
> combined = t.combine_chunks(){code}
> I get the following error
> {code:java}
> --------------------------------------------------------------------------- ArrowInvalid Traceback (most recent call last) /var/folders/x6/00594j4s2yv3swcn98bn8gxr0000gn/T/ipykernel_95780/4128956270.py in <module> ----> 1 z=t.combine_chunks()
> ~/.venv/lib/python3.7/site-packages/pyarrow/table.pxi in pyarrow.lib.ChunkedArray.combine_chunks() 
> ~/.venv/lib/python3.7/site-packages/pyarrow/array.pxi in pyarrow.lib.concat_arrays() ~/Documents/Github/dataquality/.venv/lib/python3.7/site-packages/pyarrow/error.pxi in pyarrow.lib.pyarrow_internal_check_status() ~.venv/lib/python3.7/site-packages/pyarrow/error.pxi in pyarrow.lib.check_status() 
> ArrowInvalid: offset overflow while concatenating arrays {code}
> With smaller strings or smaller arrays this works fine.
> {code:java}
> x = str(np.random.randint(low=0,high=1000, size=(10,)).tolist())
> t = pa.chunked_array([x]*1000)
> combined = t.combine_chunks(){code}
> The first example that fails takes a few minutes to run. If you'd like a faster example for experimentation, you can use `vaex` to generate the chunked array much faster. This will throw the identical error and will run about 1 second.
> {code:java}
> import vaex
> import numpy as np
> n = 50_000
> x = str(np.random.randint(low=0,high=1000, size=(30_000,)).tolist())
> df = vaex.from_arrays(
>     id=list(range(n)),
>     y=np.random.randint(low=0,high=1000,size=n)
> )
> df["text"] = vaex.vconstant(x, len(df))
> # text_chunk_array is now a pyarrow.lib.ChunkedArray
> text_chunk_array = df.text.values
> x = text_chunk_array.combine_chunks() {code}
>  
>  
>  



--
This message was sent by Atlassian Jira
(v8.20.10#820010)