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41 lines
2.0 KiB
Go
41 lines
2.0 KiB
Go
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/*
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Migrate handles translating the state of the blockchain between software versions.
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For example, as modules are changed over time the structure of the data they store changes. The data structure must be
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migrated to the new structure of the newer versions.
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There are two types of migration:
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- **genesis migration** a script converts an exported genesis file from the old software to a new genesis file for the new software
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- **live upgrade** a handler in the upgrade module converts data in the database itself from the old version to the new
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Genesis migration starts a whole new blockchain (with new chain-id) for the new software version.
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Live upgrade keeps the blockchain (and chain-id) the same for the new software version.
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We only support migrations between mainnet kava releases.
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We only support migrations from the previous mainnet kava version to the current. We don't support migrating between two old versions, use the old software version for this.
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We only support migrations from old to new versions, not the other way around.
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Genesis Migration
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The process is:
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- unmarshal the current genesis file into the old `GenesisState` type that has been copied into a `legacy` folder (ideally using the old codec version)
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- convert that `GenesisState` to the current `GenesisState` type
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- marshal it to json (using current codec)
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On each release we can delete the previous releases migration and old GenesisState type.
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eg kava-3 migrates `auth.GenesisState` from kava-2 to `auth.GenesisState` from kava-3,
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but for kava-4 we don't need to keep around kava-2's `auth.GenesisState` type.
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This folder contains old types from several sdk modules because they needed custom migrations for kava-3.
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The sdk version for kava-2 was a master commit 18de63.
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Live Upgrade
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The process is:
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- submit upgrade proposal on old chain
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- old chain halts
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- people download new version and restart their validators
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- on start the new upgrade handler runs
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- use copypasted old keeper and types to read from db, convert to current types and write with current keeper
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*/
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package migrate
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