cosmos-sdk/x/distribution/spec/02_state.md
Julien Robert 58597139fa
docs: Improve markdownlint configuration (#11104)
## Description

Closes: #9404



---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [x] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [x] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [x] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [x] reviewed "Files changed" and left comments if necessary
- [x] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)
2022-02-10 12:07:01 +00:00

2.0 KiB

State

FeePool

All globally tracked parameters for distribution are stored within FeePool. Rewards are collected and added to the reward pool and distributed to validators/delegators from here.

Note that the reward pool holds decimal coins (DecCoins) to allow for fractions of coins to be received from operations like inflation. When coins are distributed from the pool they are truncated back to sdk.Coins which are non-decimal.

  • FeePool: 0x00 -> ProtocolBuffer(FeePool)
// coins with decimal
type DecCoins []DecCoin

type DecCoin struct {
    Amount sdk.Dec
    Denom  string
}

+++ https://github.com/cosmos/cosmos-sdk/blob/v0.40.0/proto/cosmos/distribution/v1beta1/distribution.proto#L94-L101

Validator Distribution

Validator distribution information for the relevant validator is updated each time:

  1. delegation amount to a validator is updated,
  2. a validator successfully proposes a block and receives a reward,
  3. any delegator withdraws from a validator, or
  4. the validator withdraws its commission.
  • ValidatorDistInfo: 0x02 | ValOperatorAddrLen (1 byte) | ValOperatorAddr -> ProtocolBuffer(validatorDistribution)
type ValidatorDistInfo struct {
    OperatorAddress     sdk.AccAddress
    SelfBondRewards     sdk.DecCoins
    ValidatorCommission types.ValidatorAccumulatedCommission
}

Delegation Distribution

Each delegation distribution only needs to record the height at which it last withdrew fees. Because a delegation must withdraw fees each time it's properties change (aka bonded tokens etc.) its properties will remain constant and the delegator's accumulation factor can be calculated passively knowing only the height of the last withdrawal and its current properties.

  • DelegationDistInfo: 0x02 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValOperatorAddrLen (1 byte) | ValOperatorAddr -> ProtocolBuffer(delegatorDist)
type DelegationDistInfo struct {
    WithdrawalHeight int64    // last time this delegation withdrew rewards
}