Lower transaction size limit to 1.5MiB #11379
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The size limit for a single single transaction used to be 4MiB, this PR reduces it to 1.5MiB. Transactions larger than 1.5MiB will be rejected. This is done to help with near#11103. It's hard to limit the size of `ChunkStateWitness` when a single transaction can be as large as 4MiB. Having 1.5MiB transactions makes things much more manageable. This will break some transactions. On current mainnet there is approximately one transaction larger than 1.5MiB per day (~420 large txs per year). We've decided that it's okay to break those transactions. The new limit is introduced in protocol version `68`. This protocol version could be released before the full stateless validation launch, to see if anyone complains. Note that this change doesn't limit the size of receipts, only transactions. It's still possible to create a receipt with a 4MiB contract or function call, but that's out of scope for the transaction size limit. Zulip discussion about lowering the limit: https://near.zulipchat.com/#narrow/stream/295306-contract-runtime/topic/.E2.9C.94.20Lowering.20the.20limit.20for.20contract.20code.20size
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I guess #11368 would help with that... |
wacban
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May 23, 2024
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Does setting lower max_transaction_size implicitly limit the contract size as well?
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Not necessarily, as the size limit for receipts is still 4MiB, so I think that a contract could potentially deploy another 4MiB contract.
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But still it will make it impossible to deploy a large contract using the most common case of deploy action in a single transaction right? Just to be clear I'm not against it, just making sure that you considered this consequence.
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But still it will make it impossible to deploy a large contract using the most common case of deploy action in a single transaction right?
Yes, it's a breaking change :/
I'm currently focused on limiting transactions, so this PR only adds a limit for transactions, but in the future that might be extended to receipts as well. (possibly for #11295)
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Closing in favor of #11406 |
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…1406) Fixes: #11103 This PR adds 3 new limitations to control total size of transactions included in ChunkStateWitness 1) Reduce `max_transaction_size` from 4MiB to 1.5MiB. Transactions larger than 1.5MiB will be rejected. 2) Limit size of transactions included in the last two chunks to 2MiB. `ChunkStateWitness` contains transactions from both the current and the previous chunk, so we have to limit the sum of transactions from both of those chunks. 3) Limit size of storage proof generated during transaction validation to 500kiB (soft limit). In total that limits the size transaction related fields to 2.5MiB. About 1): Having 4MiB transactions is troublesome, because it means that we have to allow at least 4MiB of transactions to be included in `ChunkStateWitness`. Having so much space taken up by the transactions could cause problems with witness size. See #11379 for more information. About 2): `ChunkStateWitness` contains both transactions from the previous chunk (`transactions`) and the new chunk (`new_transactions`). This is annoying because it halves the space that we can reserve for transactions. To make sure that the size stays reasonable we limit the sum of both those fields to 2MiB. On current mainnet traffic the sum of these fields stays under 400kiB, so 2MiB should be more than enough. This limit has to be slightly higher than the limit for a single transaction, so we can't make it 1MiB, it has to be at least 1.5MiB. About 3): On mainnet traffic the size of transactions storage proof is under 500kiB on most chunks, so adding this limit shouldn't affect the throughput. I assume that every transactions generates a limited amount of storage proof during validation, so we can have a soft limit for the total size of storage proof. Implementing a hard limit would be difficult because it's hard to predict how much storage proof will be generated by validating a transaction. Transactions are validated by running `prepare_transactions` on the validator, so there's no need for separate validation code.
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Lower transaction size limit to 1.5MiB
The size limit for a single transaction used to be 4MiB, this PR reduces it to 1.5MiB. Transactions larger than 1.5MiB will be rejected.
This is done to help with #11103. It's hard to limit the size of
ChunkStateWitnesswhen a single transaction can be as large as 4MiB. Having 1.5MiB transactions makes things much more manageable.This will break some transactions.
On current mainnet there is approximately one transaction larger than 1.5MiB per day (~420 large txs per year).
We've decided that it's okay to break those transactions.
List of transactions larger than 1.5MiB from the last year of mainnet traffic: broken-transactions.txt
The new limit is introduced in protocol version
68.This protocol version could be released before the full stateless validation launch, to see if anyone complains.
Note that this change doesn't limit the size of receipts, only transactions. It's still possible to create a receipt with a 4MiB contract or function call, but that's out of scope for the transaction size limit.
Zulip discussion about lowering the limit: https://near.zulipchat.com/#narrow/stream/295306-contract-runtime/topic/.E2.9C.94.20Lowering.20the.20limit.20for.20contract.20code.20size