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
}

// FeePool is the global fee pool for distribution.
message FeePool {
  repeated cosmos.base.v1beta1.DecCoin community_pool = 1
      [(gogoproto.nullable) = false, (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins"];
}

Validator Distribution

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

1. delegation amount to a validator is updated,

2. any delegator withdraws from a validator, or

3. 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
}

Params

The distribution module stores it's params in state with the prefix of 0x09, it can be updated with governance or the address with authority.

• Params: 0x09 | ProtocolBuffer(Params)

// Params defines the set of params for the distribution module.
message Params {
  option (gogoproto.goproto_stringer) = false;
  string community_tax                = 1 [
    (cosmos_proto.scalar)  = "cosmos.Dec",
    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
    (gogoproto.nullable)   = false
  ];
  string base_proposer_reward = 2 [
    (cosmos_proto.scalar)  = "cosmos.Dec",
    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
    (gogoproto.nullable)   = false
  ];
  string bonus_proposer_reward = 3 [
    (cosmos_proto.scalar)  = "cosmos.Dec",
    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
    (gogoproto.nullable)   = false
  ];
  bool withdraw_addr_enabled = 4;
}