Install_code from canister limited to 2mb as well?

Developers
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It’s probably a stupid question but, out of nowhere, I have a doubt for no reason.

Can a canister that holds some wasm code as a blob (e.g. Vec<u8>) and calls install_code targeting another canister install more than 2 MB?

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It’s possible, but some work would need to be done, in comparison to DFX, which will handle the chunked upload for you. You need to use install_chunked_code after upload_chunk.

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Thanks Nathan so, to answer concretlly my question: if a canister holds e.g. 5mb of wasm it cannot call install_code targeting another canister because as for any install_code it will hit the 2mb message limitation. Correct?

In other words, regardless where you call install_code, the 2mb limit absolutely always apply.

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Yes there is still the 2mb message limit on install_code. The same is also true for upload_chunk and install_chunked_code.

A 5mb WASM would need to be uploaded with 3 separate calls (each less than 2mb) to the target canister’s blob storage using upload_chunk and then installed using install_chunked_code.

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Thanks for the confirmation. I don’t know why I had some doubt but, “there is no such thing as stupid question” isn’t :wink: .

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IIRC the 2mb limit is only there for ingress messages and cross-net calls, if a canister calls another canister in the same subnet then the limit is 10mb (source).

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Nice, I didn’t know about that. Thanks!

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Thanks Kepler, that’s good to know!

Btw. install_chunked_code is also limited to 10mb right? Looks like it is not documented on the website. MAX_CHUNKS_IN_LARGE_WASM and CHUNK_STORE_SIZE are referenced but their effective values is not displayed unless I missed an information :man_shrugging:.

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Each chunk must be at most 1MiB. That is documented here. But ideally this would be added to the resource limits table as well.

Additionally, not mentioned in the spec: The resulting wasm must be at most 100 chunks / MiB, with the additional restriction that the code section must be no larger than 10MiB. But this leaves room to bundle in assets and metadata larger than 10MiB.

@bogwar: Could you please confirm the above numbers?

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Thanks @frederikrothenberger; the limits are indeed as you stated them. I’ll see it to add the limits to the resource limit table.