[QUESTION] - Polygon CDK Upgrade - Fork9 to Fork12 Migration

[okalenyk]

Our team has built an isolated chain based on polygon cdk a while ago. Right now it is running Fork9(Elderberry) and we're trying to upgrade it to Fork12. We've been using the original doc as a guide.

The issue is that when we run a fork12 sequencer which is connected to the current fork9 sequencer - it syncs blocks from scratch(we've provided the genesis root hash from the current fork9 chain) up to the latest one from sequencer datastream. Then the cdk erigon node is building the SMT2 - finishes it but throws an error - Root mismatch with SMT v2 expected=... got=....

Does it mean that our node is incompatible for fork12 migration?

[okalenyk]

@IvanBelyakoff @revitteth @elliothllm @hexoscott Can you help with this?

[obynonwane]

Hey @okalenyk

This issue might occur because Fork 12 likely introduces updates to the Sparse Merkle Tree (SMT v2), which change how state roots are computed and verified.
The state structure used in Fork 9 may therefore not be directly compatible with the Fork 12 SMT implementation.

As a result, a Fork 12 compatible node may not be able to continue syncing from a Fork 9 sequencer, even if the genesis hash is the same, since the computed state roots will not match.

Possible resolution:
• Upgrade both the sequencer and the node to Fork 12, and resync from scratch so all components use the same SMT version and state model.

documentation
Using kurtosis Steps

cc @hexoscott

[okalenyk]

Thank you @obynonwane! I'll have a look at the kurtosis steps document however I'm a bit worried about this - The process here isn’t exactly suitable for production environments (c), but I will try the upgrade locally and let you know if it works. We have also a staging(testnet) chain running so we could try the upgrade there if it works locally.