State Export/Import

Cosmos EVM can dump the entire application state to a JSON file. This, besides upgrades, can be useful for manual analysis of the state at a given height.

Export State​

Export state with:

evmd export > new_genesis.json

You can also export state from a particular height (at the end of processing the block of that height):

evmd export --height [height] > new_genesis.json

If you plan to start a new network for 0 height (i.e genesis) from the exported state, export with the --for-zero-height flag:

evmd export --height [height] --for-zero-height > new_genesis.json

Manually Migrate State​

If you want to migrate state manually, e.g. for local testing purpose. Note that for regular chain upgrades, a manual state migration is not required.

After exporting your state into a json file, you can replace the old genesis.json with new_genesis.json.

cp -f genesis.json new_genesis.jsonmv new_genesis.json genesis.json

At this point, you might want to run a script to update the exported genesis into a genesis state that is compatible with your new version.

You can use the migrate command to migrate from a given version to the next one (eg: v0.X.X to v1.X.X):

evmd migrate TARGET_VERSION GENESIS_FILE --chain-id=<new_chain_id> --genesis-time=<yyyy-mm-ddThh:mm:ssZ>