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ARROW-362: Remove redunant reference count #198

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xhochy wants to merge 4 commits into from
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ARROW-362: Remove redunant reference count #198

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ARROW-362: Remove redunant reference count
xhochy Nov 3, 2016
d85228f
Be more careful about reference counts in zero-copy handoff, add pyar…
wesm Nov 6, 2016
99df96b
Force gc to avoid non-deterministic failure
wesm Nov 7, 2016
bd2bf22
Merge pull request #1 from wesm/ARROW-362
xhochy Nov 7, 2016
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1 change: 0 additions & 1 deletion python/src/pyarrow/adapters/pandas.cc
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Expand Up @@ -628,7 +628,6 @@ class ArrowDeserializer {
PyAcquireGIL lock;

// Zero-Copy. We can pass the data pointer directly to NumPy.
Py_INCREF(py_ref_);
OwnedRef py_ref(py_ref_);
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@wesm wesm Nov 6, 2016 •
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I'm surprised by this -- PyArray_SetBaseObject claims to steal a reference (https://docs.scipy.org/doc/numpy-dev/reference/c-api.array.html#c.PyArray_SetBaseObject), so if we are not incrementing the memory owner's reference count, then it could get garbage collected while the NumPy array is still alive. I believe you that it's leaking memory. To really be sure about this, we may wish to expose the ConvertArrayToPandas method in pyarrow.Array.to_pandas and then examine the reference counts before and after the conversion.

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@wesm wesm Nov 6, 2016

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I'm going to dig into this a little myself out of curiosity

npy_intp dims[1] = {col_->length()};
out_ = reinterpret_cast<PyArrayObject*>(PyArray_SimpleNewFromData(1, dims,
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