Hi,
I'm using Jpype to pass streams between java and python back and forth.
For follow code works fine with its release callback
```python
with child_allocator("test-allocator") as allocator:
r = some_package.InMemoryArrowReader.create(allocator)
c_stream = arrow_c.new("struct ArrowArrayStream*")
c_stream_ptr = int(arrow_c.cast("uintptr_t", c_stream))
s = org.apache.arrow.c.ArrowArrayStream.wrap(c_stream_ptr)
org.apache.arrow.c.Data.exportArrayStream(allocator, r, s)
with pa.RecordBatchReader._import_from_c(c_stream_ptr) as stream:
for rb in stream: # type: pa.RecordBatch
logger.info(rb.num_rows) # yield weakref.proxy(rb)
del rb # release callback directly called in current thread?
```
But if del statment not called, the allocator from java side would
raise exception that memory leaks.
Also, an warning message output to err
```
WARNING: Failed to release Java C Data resource: Failed to attach the
current thread to a Java VM
```
which comes from
https://github.com/apache/arrow/blob/5cc6aa3551c6d0dc1285ea1eb587325ae3491a7f/java/c/src/main/cpp/jni_wrapper.cc#L182
Then, how can I find which thread called the release callback? Or, how
can I make sure release callback is called at the last line
I was trying to wrap the code into a managed RecordBatchReader with
generator (replace with `yield rb` in the loop), but the object is
still referenced by downstream users.
Is yielding a weakref-ed `rb` a good idea? Will the weakref-ed
RecordBatchReader works with other pyarrow api (dataset)?
--
---------------------
Best Regards,
Wenbo Hu,
