Bug

I have a use case where I need to query a collection that returns about ~1M object, which when my scripts is running I see memory usage upward of 1G. I thought this shouldn't happen as I am iterating over the cursor and not reading all object to memory at once.

Current Behavior

async for data in ENGINE.find(Data):
    # do something with data

this will loads all object to memory because of __aiter__ method in AIOCursor :

async def __aiter__(self) -> AsyncGenerator[ModelType, None]:
    if self._results is not None:
        for res in self._results:
            yield res
        return
    results = []
    async for raw_doc in self._cursor:
        instance = self._parse_document(raw_doc)
        results.append(instance)
        yield instance
    self._results = results

Expected behavior

shouldn't __aiter__ yield each instance without caching it to memory since I'm iterating over the cursor not reading all object to memory?

ex:

async def __aiter__(self) -> AsyncGenerator[ModelType, None]:
    async for raw_doc in self._cursor:
        instance = self._parse_document(raw_doc)
        yield instance

Environment

• ODMantic version: 1.0.2
• MongoDB version: 7.0.9
• Pydantic infos (output of python -c "import pydantic.utils; print(pydantic.utils.version_info())):

             pydantic version: 2.7.3
        pydantic-core version: 2.18.4
          pydantic-core build: profile=release pgo=true
                 install path: /home/<redacted>/.venv/lib/python3.12/site-packages/pydantic
               python version: 3.12.3 (main, Apr 27 2024, 19:00:26) [GCC 9.4.0]
                     platform: Linux-5.4.0-182-generic-x86_64-with-glibc2.31
             related packages: mypy-1.10.0 typing_extensions-4.12.1 pydantic-settings-2.3.1 fastapi-0.111.0
                       commit: unknown

Additional context

Curios why it needs to cache instance to a private variable when I'm iterating over the cursor.