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@kou @bkietz This extra check and release should be the responsibility of the underlying iterator instead of forcing every abstract iterator to behave this way.
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Could you explain the reason? Performance?
For the #41771 case:
This is the underlying iterator:
arrow/cpp/src/arrow/dataset/scanner.cc
Lines 380 to 386 in 7f0c407
We want to release the IPC reader created at:
arrow/cpp/src/arrow/dataset/file_ipc.cc
Line 144 in 7bc2452
It's referred by the underlying iterator indirectly via
Future
/std::function
.It seems that we can't remove a reference from
Future
/std::function
without deletingFuture
/std::function
and we can't deleteFuture
/std::function
without deleting the underlying iterator.There was a problem hiding this comment.
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Performance, binary code size, and overall elegance of the iterator tree.
But I see that it's not possible because these iterators are like C++ in that the iterator itself is the value as well instead of being something that produces the value. So just ignore my comment.