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queue.SimpleQueue.__sizeof__() ignores the underlying data structure #140025
Description
Bug report
Bug description:
queue.SimpleQueue (C level) uses a list on Python < 3.13[1][2][3][4], a ring buffer on Python >= 3.13[5][6]. However, it does not implement its own __sizeof__() method, and as a result, only the size of the simplequeueobject structure itself (basicsize) is taken as the size of the object, while the size of the underlying structure is ignored.
>>> from queue import SimpleQueue
>>> q = SimpleQueue()
>>> q.__sizeof__()
72 # 56 on Python < 3.13
>>> for _ in range(1_000):
... q.put(object())
...
>>> q.__sizeof__()
72 # 56 on Python < 3.13Expected (should be, on Python >= 3.13):
>>> from queue import SimpleQueue
>>> q = SimpleQueue()
>>> q.__sizeof__()
136 # == 72 + 8*8 == sizeof(simplequeueobject) + sizeof(PyObject *)*INITIAL_RING_BUF_CAPACITY
>>> for _ in range(1_000):
... q.put(object())
...
>>> q.__sizeof__()
8264 # == 72 + 8*1024 == sizeof(simplequeueobject) + sizeof(PyObject *)*pow(2, ceil(log2(1000)))CPython versions tested on:
3.9, 3.10, 3.11, 3.12, 3.13, 3.14
Operating systems tested on:
Linux
Activity
pitrou commentedon Oct 14, 2025
I'm going to unassign myself as I'm not really active anymore.
pitrou commentedon Oct 14, 2025
cc @mpage
fix: pythongh-140025 queue.SimpleQueue.__sizeof__() ignores the under…
fix: pythongh-140025 queue.SimpleQueue.__sizeof__() ignores the under…
fix: pythongh-140025 queue.SimpleQueue.__sizeof__() ignores the under…
Fix queue.SimpleQueue.__sizeof__() to account for buffer
picnixz commentedon Dec 30, 2025
Removing the easy label because we already have a PR for that. For newcomers, don't create a PR if one already exists.
gh-140025: Fix `queue.SimpleQueue.__sizeof__()` to return correct size (
pythongh-140025: Fix `queue.SimpleQueue.__sizeof__()` to return corre…
pythongh-140025: Fix `queue.SimpleQueue.__sizeof__()` to return corre…