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https://issues.apache.org/jira/browse/ARROW-1382?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated ARROW-1382:
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Labels: pull-request-available (was: )
> [Python] Deduplicate non-scalar Python objects when using pyarrow.serialize
> ---------------------------------------------------------------------------
>
> Key: ARROW-1382
> URL: https://issues.apache.org/jira/browse/ARROW-1382
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
> Reporter: Robert Nishihara
> Priority: Major
> Labels: pull-request-available
> Fix For: 0.13.0
>
>
> If a Python object appears multiple times within a list/tuple/dictionary,
> then when pyarrow serializes the object, it will duplicate the object many
> times. This leads to a potentially huge expansion in the size of the object
> (e.g., the serialized version of {{100 * [np.zeros(10 ** 6)]}} will be 100
> times bigger than it needs to be).
> {code}
> import pyarrow as pa
> l = [0]
> original_object = [l, l]
> # Serialize and deserialize the object.
> buf = pa.serialize(original_object).to_buffer()
> new_object = pa.deserialize(buf)
> # This works.
> assert original_object[0] is original_object[1]
> # This fails.
> assert new_object[0] is new_object[1]
> {code}
> One potential way to address this is to use the Arrow dictionary encoding.
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