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https://issues.apache.org/jira/browse/ARROW-809?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15965731#comment-15965731
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Itai Incze commented on ARROW-809:
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The reason for the bug seems to be that sliced arrays are tested with the
condition {{(array.offset() != 0)}} throughout {{arrow/ipc/writer.cc}}, which
doesn't account for a {{\[0:x\]}} slice.
To test for 0-based slices there's a need to know the number of elements in the
original array, which is easily computed in cases like fixed-width array types
but could be harder in others.
Another approach could be adding a class member to mark the slices. This could
be either by a simple boolean, the original dimensions or a reference to the
original array.
> C++: Writing sliced record batch to IPC writes the entire array
> ---------------------------------------------------------------
>
> Key: ARROW-809
> URL: https://issues.apache.org/jira/browse/ARROW-809
> Project: Apache Arrow
> Issue Type: Bug
> Components: C++
> Reporter: Itai Incze
> Priority: Minor
>
> The bug can be triggered through python:
> {code}
> import pyarrow.parquet
> array = pyarrow.array.from_pylist([1] * 1000000)
> rb = pyarrow.RecordBatch.from_arrays([array], ['a'])
> rb2 = rb.slice(0,2)
> with open('/tmp/t.arrow', 'wb') as f:
> w = pyarrow.ipc.FileWriter(f, rb.schema)
> w.write_batch(rb2)
> w.close()
> {code}
> which will result in a big file:
> {code}
> $ ll /tmp/t2.arrow
> -rw-rw-r-- 1 itai itai 800618 Apr 12 13:22 /tmp/t.arrow
> {code}
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