[BUG] Buffer crashes on extend

[matteobettini]

The buffer hangs on the extend operation and then crashes with Process finished with exit code 137 (interrupted by signal 9:SIGKILL)

To reproduce, check out #2054

from torchrl.data import LazyTensorStorage, RandomSampler, TensorDictReplayBuffer
from torchrl.envs import MeltingpotEnv

if __name__ == "__main__":
    env = MeltingpotEnv(substrate="commons_harvest__open")
    td = env.rollout(max_steps=100, break_when_any_done=False)

    buffer = TensorDictReplayBuffer(
        storage=LazyTensorStorage(1_000_000, device="cpu"),
        sampler=RandomSampler(),
        batch_size=10,
    )

    buffer.extend(td) # Hangs and then -> Process finished with exit code 137 (interrupted by signal 9:SIGKILL)

This is where it hangs (specifically on expand().clone()

rl/torchrl/data/replay_buffers/storages.py

Lines 929 to 942 in cf685b7

	if is_tensor_collection(data):
	out = (
	data.expand(max_size_along_dim0(data.shape))
	.clone()
	.zero_()
	.to(self.device)
	)
	elif is_tensor_collection(data):
	out = (
	data.expand(max_size_along_dim0(data.shape))
	.clone()
	.zero_()
	.to(self.device)
	)

PS these are 2 indentical if branches?

[vmoens]

PS these are 2 indentical if branches?

Yeah it used to be one for tensorclass and one for tensordict but then they became identical and I didn't catch it :)

[vmoens]

I think your buffer is simply too big to fit in memory, using LazyMemmapStorage or a smaller buffer size solved the issue

[matteobettini]

If this is the case I think there should be an error here, it is currently silently crashing

[vmoens]

it actually does

Exit code 137 is a signal that occurs when a container's memory exceeds the memory limit provided in the pod specification.