staking overview.md revisions, moving files

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rigelrozanski 2018-05-18 14:26:32 -04:00
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commit c66ded7646
10 changed files with 346 additions and 288 deletions

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@ -37,7 +37,7 @@ distribution occurs, withdrawal of fees must also occur.
- when bonding, unbonding, or re-delegating tokens to an existing account a
full withdrawal of the fees must occur (as the rules for lazy accounting
change),
- when a candidate chooses to change the commission on fees, all accumulated
- when a validator chooses to change the commission on fees, all accumulated
commission fees must be simultaneously withdrawn.
When the validator is the proposer of the round, that validator (and their
@ -52,7 +52,7 @@ that `BondedShares` represents the sum of all voting power saved in the
```
proposerReward = feesCollected * (0.01 + 0.04
* sumOfVotingPowerOfPrecommitValidators / gs.BondedShares)
candidate.ProposerRewardPool += proposerReward
validator.ProposerRewardPool += proposerReward
reserveTaxed = feesCollected * params.ReserveTax
gs.ReservePool += reserveTaxed
@ -64,13 +64,13 @@ gs.RecentFee = distributedReward
```
The entitlement to the fee pool held by the each validator can be accounted for
lazily. First we must account for a candidate's `count` and `adjustment`. The
`count` represents a lazy accounting of what that candidates entitlement to the
lazily. First we must account for a validator's `count` and `adjustment`. The
`count` represents a lazy accounting of what that validators entitlement to the
fee pool would be if there `VotingPower` was to never change and they were to
never withdraw fees.
```
candidate.count = candidate.VotingPower * BlockHeight
validator.count = validator.VotingPower * BlockHeight
```
Similarly the GlobalState count can be passively calculated whenever needed,
@ -81,9 +81,9 @@ gs.count = gs.BondedShares * BlockHeight
```
The `adjustment` term accounts for changes in voting power and withdrawals of
fees. The adjustment factor must be persisted with the candidate and modified
whenever fees are withdrawn from the candidate or the voting power of the
candidate changes. When the voting power of the candidate changes the
fees. The adjustment factor must be persisted with the validator and modified
whenever fees are withdrawn from the validator or the voting power of the
validator changes. When the voting power of the validator changes the
`Adjustment` factor is increased/decreased by the cumulative difference in the
voting power if the voting power has been the new voting power as opposed to
the old voting power for the entire duration of the blockchain up the previous
@ -91,13 +91,13 @@ block. Each time there is an adjustment change the GlobalState (denoted `gs`)
`Adjustment` must also be updated.
```
simplePool = candidate.count / gs.count * gs.SumFeesReceived
projectedPool = candidate.PrevPower * (height-1)
simplePool = validator.count / gs.count * gs.SumFeesReceived
projectedPool = validator.PrevPower * (height-1)
/ (gs.PrevPower * (height-1)) * gs.PrevFeesReceived
+ candidate.Power / gs.Power * gs.RecentFee
+ validator.Power / gs.Power * gs.RecentFee
AdjustmentChange = simplePool - projectedPool
candidate.AdjustmentRewardPool += AdjustmentChange
validator.AdjustmentRewardPool += AdjustmentChange
gs.Adjustment += AdjustmentChange
```
@ -122,55 +122,55 @@ type powerChange struct {
```
Note that the adjustment factor may result as negative if the voting power of a
different candidate has decreased.
different validator has decreased.
```
candidate.AdjustmentRewardPool += withdrawn
validator.AdjustmentRewardPool += withdrawn
gs.Adjustment += withdrawn
```
Now the entitled fee pool of each candidate can be lazily accounted for at
Now the entitled fee pool of each validator can be lazily accounted for at
any given block:
```
candidate.feePool = candidate.simplePool - candidate.Adjustment
validator.feePool = validator.simplePool - validator.Adjustment
```
So far we have covered two sources fees which can be withdrawn from: Fees from
proposer rewards (`candidate.ProposerRewardPool`), and fees from the fee pool
(`candidate.feePool`). However we should note that all fees from fee pool are
subject to commission rate from the owner of the candidate. These next
proposer rewards (`validator.ProposerRewardPool`), and fees from the fee pool
(`validator.feePool`). However we should note that all fees from fee pool are
subject to commission rate from the owner of the validator. These next
calculations outline the math behind withdrawing fee rewards as either a
delegator to a candidate providing commission, or as the owner of a candidate
delegator to a validator providing commission, or as the owner of a validator
who is receiving commission.
### Calculations For Delegators and Candidates
### Calculations For Delegators and Validators
The same mechanism described to calculate the fees which an entire validator is
entitled to is be applied to delegator level to determine the entitled fees for
each delegator and the candidates entitled commission from `gs.FeesPool` and
`candidate.ProposerRewardPool`.
each delegator and the validators entitled commission from `gs.FeesPool` and
`validator.ProposerRewardPool`.
The calculations are identical with a few modifications to the parameters:
- Delegator's entitlement to `gs.FeePool`:
- entitled party voting power should be taken as the effective voting power
after commission is retrieved,
`bond.Shares/candidate.TotalDelegatorShares * candidate.VotingPower * (1 - candidate.Commission)`
- Delegator's entitlement to `candidate.ProposerFeePool`
`bond.Shares/validator.TotalDelegatorShares * validator.VotingPower * (1 - validator.Commission)`
- Delegator's entitlement to `validator.ProposerFeePool`
- global power in this context is actually shares
`candidate.TotalDelegatorShares`
`validator.TotalDelegatorShares`
- entitled party voting power should be taken as the effective shares after
commission is retrieved, `bond.Shares * (1 - candidate.Commission)`
- Candidate's commission entitlement to `gs.FeePool`
commission is retrieved, `bond.Shares * (1 - validator.Commission)`
- Validator's commission entitlement to `gs.FeePool`
- entitled party voting power should be taken as the effective voting power
of commission portion of total voting power,
`candidate.VotingPower * candidate.Commission`
- Candidate's commission entitlement to `candidate.ProposerFeePool`
`validator.VotingPower * validator.Commission`
- Validator's commission entitlement to `validator.ProposerFeePool`
- global power in this context is actually shares
`candidate.TotalDelegatorShares`
`validator.TotalDelegatorShares`
- entitled party voting power should be taken as the of commission portion
of total delegators shares,
`candidate.TotalDelegatorShares * candidate.Commission`
`validator.TotalDelegatorShares * validator.Commission`
For more implementation ideas see spreadsheet `spec/AbsoluteFeeDistrModel.xlsx`
@ -186,9 +186,45 @@ rate, all commission on fees must be simultaneously withdrawn.
reaches maturity and shares are re-delegated all available fees are
simultaneously withdrawn.
- Whenever a totally new validator is added to the validator set, the `accum`
of the entire candidate must be 0, meaning that the initial value for
`candidate.Adjustment` must be set to the value of `canidate.Count` for the
height which the candidate is added on the validator set.
of the entire validator must be 0, meaning that the initial value for
`validator.Adjustment` must be set to the value of `canidate.Count` for the
height which the validator is added on the validator set.
- The feePool of a new delegator bond will be 0 for the height at which the bond
was added. This is achieved by setting `DelegatorBond.FeeWithdrawalHeight` to
the height which the bond was added.
### Atom provisions
Validator provisions are minted on an hourly basis (the first block of a new
hour). The annual target of between 7% and 20%. The long-term target ratio of
bonded tokens to unbonded tokens is 67%.
The target annual inflation rate is recalculated for each provisions cycle. The
inflation is also subject to a rate change (positive or negative) depending on
the distance from the desired ratio (67%). The maximum rate change possible is
defined to be 13% per year, however the annual inflation is capped as between
7% and 20%.
```go
inflationRateChange(0) = 0
Inflation(0) = 0.07
bondedRatio = Pool.BondedTokens / Pool.TotalSupplyTokens
AnnualInflationRateChange = (1 - bondedRatio / 0.67) * 0.13
annualInflation += AnnualInflationRateChange
if annualInflation > 0.20 then Inflation = 0.20
if annualInflation < 0.07 then Inflation = 0.07
provisionTokensHourly = Pool.TotalSupplyTokens * Inflation / (365.25*24)
```
Because the validators hold a relative bonded share (`GlobalStakeShares`), when
more bonded tokens are added proportionally to all validators, the only term
which needs to be updated is the `GlobalState.BondedPool`. So for each
provisions cycle:
```go
Pool.BondedPool += provisionTokensHourly
```

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@ -0,0 +1,19 @@
### TxProveLive
If a validator was automatically unbonded due to liveness issues and wishes to
assert it is still online, it can send `TxProveLive`:
```golang
type TxProveLive struct {
PubKey crypto.PubKey
}
```
All delegators in the temporary unbonding pool which have not
transacted to move will be bonded back to the now-live validator and begin to
once again collect provisions and rewards.
```
TODO: pseudo-code
```

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@ -2,30 +2,38 @@
## Abstract
This paper specifies the Staking module of the Cosmos-SDK, which was first described in the [Cosmos Whitepaper](https://cosmos.network/about/whitepaper) in June 2016.
This paper specifies the Staking module of the Cosmos-SDK, which was first
described in the [Cosmos Whitepaper](https://cosmos.network/about/whitepaper)
in June 2016.
The module enables Cosmos-SDK based blockchain to support an advanced Proof-of-Stake system. In this system, holders of the native staking token of the chain can become candidate validators and can delegate tokens to candidate validators, ultimately determining the effective validator set for the system.
The module enables Cosmos-SDK based blockchain to support an advanced
Proof-of-Stake system. In this system, holders of the native staking token of
the chain can become validators and can delegate tokens to validator
validators, ultimately determining the effective validator set for the system.
This module will be used in the Cosmos Hub, the first Hub in the Cosmos network.
This module will be used in the Cosmos Hub, the first Hub in the Cosmos
network.
## Contents
The following specification uses *Atom* as the native staking token. The module can be adapted to any Proof-Of-Stake blockchain by replacing *Atom* with the native staking token of the chain.
The following specification uses *Atom* as the native staking token. The module
can be adapted to any Proof-Of-Stake blockchain by replacing *Atom* with the
native staking token of the chain.
1. **[Design overview](overview.md)**
2. **Implementation**
1. **[State](state.md)**
1. Global State
2. Validator Candidates
3. Delegator Bonds
4. Unbond and Rebond Queue
1. Params
1. Pool
2. Validators
3. Delegations
2. **[Transactions](transactions.md)**
1. Declare Candidacy
2. Edit Candidacy
3. Delegate
4. Unbond
5. Redelegate
6. ProveLive
1. Create-Validator
2. Edit-Validator
3. Repeal-Revocation
4. Delegate
5. Unbond
6. Redelegate
3. **[Validator Set Changes](valset-changes.md)**
1. Validator set updates
2. Slashing

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@ -2,100 +2,125 @@
## Overview
The Cosmos Hub is a Tendermint-based Proof of Stake blockchain system that
serves as a backbone of the Cosmos ecosystem. It is operated and secured by an
open and globally decentralized set of validators. Tendermint consensus is a
Byzantine fault-tolerant distributed protocol that involves all validators in
the process of exchanging protocol messages in the production of each block. To
avoid Nothing-at-Stake problem, a validator in Tendermint needs to lock up
coins in a bond deposit. Tendermint protocol messages are signed by the
validator's private key, and this is a basis for Tendermint strict
accountability that allows punishing misbehaving validators by slashing
(burning) their bonded Atoms. On the other hand, validators are rewarded for
The Cosmos Hub is a Tendermint-based Delegated Proof of Stake (DPos) blockchain
system that serves as a backbone of the Cosmos ecosystem. It is operated and
secured by an open and globally decentralized set of validators. Tendermint
consensus is a Byzantine fault-tolerant distributed protocol that involves all
validators in the process of exchanging protocol messages in the production of
each block. To avoid Nothing-at-Stake problem, a validator in Tendermint needs
to lock up coins in a bond deposit. Tendermint protocol messages are signed by
the validator's private key, and this is a basis for Tendermint strict
accountability that allows punishing misbehaving validators by slashing
(burning) their bonded Atoms. On the other hand, validators are rewarded for
their service of securing blockchain network by the inflationary provisions and
transactions fees. This incentives correct behavior of the validators and
transactions fees. This incentives correct behavior of the validators and
provides the economic security of the network.
The native token of the Cosmos Hub is called Atom; becoming a validator of the
The native token of the Cosmos Hub is called Atom; becoming a validator of the
Cosmos Hub requires holding Atoms. However, not all Atom holders are validators
of the Cosmos Hub. More precisely, there is a selection process that determines
the validator set as a subset of all validator candidates (Atom holders that
wants to become a validator). The other option for Atom holder is to delegate
their atoms to validators, i.e., being a delegator. A delegator is an Atom
holder that has bonded its Atoms by delegating it to a validator (or validator
candidate). By bonding Atoms to secure the network (and taking a risk of being
slashed in case of misbehaviour), a user is rewarded with inflationary
provisions and transaction fees proportional to the amount of its bonded Atoms.
The Cosmos Hub is designed to efficiently facilitate a small numbers of
validators (hundreds), and large numbers of delegators (tens of thousands).
More precisely, it is the role of the Staking module of the Cosmos Hub to
support various staking functionality including validator set selection,
delegating, bonding and withdrawing Atoms, and the distribution of inflationary
provisions and transaction fees.
the validator set as a subset of all validators (Atom holders that
wants to become a validator). The other option for Atom holder is to delegate
their atoms to validators, i.e., being a delegator. A delegator is an Atom
holder that has bonded its Atoms by delegating it to a validator. By bonding
Atoms to secure the network (and taking a risk of being slashed in case of
misbehaviour), a user is rewarded with inflationary provisions and transaction
fees proportional to the amount of its bonded Atoms. The Cosmos Hub is
designed to efficiently facilitate a small numbers of validators (hundreds),
and large numbers of delegators (tens of thousands). More precisely, it is the
role of the Staking module of the Cosmos Hub to support various staking
functionality including validator set selection, delegating, bonding and
withdrawing Atoms, and the distribution of inflationary provisions and
transaction fees.
## Basic Terms and Definitions
* Cosmsos Hub - a Tendermint-based Proof of Stake blockchain system
* Cosmsos Hub - a Tendermint-based Delegated Proof of Stake (DPos)
blockchain system
* Atom - native token of the Cosmsos Hub
* Atom holder - an entity that holds some amount of Atoms
* Candidate - an Atom holder that is actively involved in the Tendermint
blockchain protocol (running Tendermint Full Node (TODO: add link to Full
Node definition) and is competing with other candidates to be elected as a
validator (TODO: add link to Validator definition))
* Validator - a candidate that is currently selected among a set of candidates
to be able to sign protocol messages in the Tendermint consensus protocol
* Delegator - an Atom holder that has bonded some of its Atoms by delegating
them to a validator (or a candidate)
* Bonding Atoms - a process of locking Atoms in a bond deposit (putting Atoms
under protocol control). Atoms are always bonded through a validator (or
candidate) process. Bonded atoms can be slashed (burned) in case a validator
process misbehaves (does not behave according to the protocol specification).
Atom holders can regain access to their bonded Atoms if they have not been
slashed by waiting an Unbonding period.
* Unbonding period - a period of time after which Atom holder gains access to
its bonded Atoms (they can be withdrawn to a user account) or they can be
re-delegated.
* Inflationary provisions - inflation is the process of increasing the Atom supply.
Atoms are periodically created on the Cosmos Hub and issued to bonded Atom holders.
The goal of inflation is to incentize most of the Atoms in existence to be bonded.
* Pool - Global object within the Cosmos Hub which accounts global state
including the total amount of bonded, unbonding, and unbonded atoms
* Validator Share - Share which a validator holds to represent its portion of
bonded, unbonding or unbonded atoms in the pool
* Delegation Share - Shares which a delegation bond holds to represent its
portion of bonded, unbonding or unbonded shares in a validator
* Bond Atoms - a process of locking Atoms in a delegation share which holds them
under protocol control.
* Slash Atoms - the process of burning atoms in the pool and assoiated
validator shares of a misbehaving validator, (not behaving according to the
protocol specification). This process devalues the worth of delegation shares
of the given validator
* Unbond Shares - Process of retrieving atoms from shares. If the shares are
bonded the shares must first remain in an inbetween unbonding state for the
duration of the unbonding period
* Redelegating Shares - Process of redelegating atoms from one validator to
another. This process is instantanious, the redelegated delegation is
slashible to the old validator for all blocks before the redelegation and to
the new validator for all new blocks.
* Validator - entity with atoms which is either actively validating the Tendermint
protocol (bonded validator) or vying to validate .
* Bonded Validator - a validator whose atoms are currently bonded and liable to
be slashed. These validators are to be able to sign protocol messages in the
Tendermint consensus protocol. There are limited number of bonded validators
at Cosmos Hub genesis there is a maximum of 100 bonded validators. Only Bonded
Validators receive atom provisions and fee rewards.
* Delegator - an Atom holder that has bonded Atoms to a validator
* Unbonding period - time required in the unbonding state when unbonding
shares. Time slashable to old validator after a redelegation. Time for which
validators can be slashed after an infraction
* Atom provisions - The process of increasing the Atom supply. Atoms are
periodically created on the Cosmos Hub and issued to bonded Atom holders.
The goal of inflation is to incentize most of the Atoms in existence to be
bonded. Atoms are distributed unbonded and using the fee_distribution mechanism
* Transaction fees - transaction fee is a fee that is included in a Cosmsos Hub
transaction. The fees are collected by the current validator set and
distributed among validators and delegators in proportion to their bonded
Atom share.
transaction. The fees are collected by the current validator set and
distributed among validators and delegators in proportion to their bonded
Atom share
* Commission fee - a fee taken from the transaction fees by a validator for
their service
their service
## The pool and the share
At the core of the Staking module is the concept of a pool which denotes a
collection of Atoms contributed by different Atom holders. There are two global
pools in the Staking module: the bonded pool and unbonding pool. Bonded Atoms
are part of the global bonded pool. If a candidate or delegator wants to unbond
its Atoms, those Atoms are moved to the the unbonding pool for the duration of
the unbonding period. In the Staking module, a pool is a logical concept, i.e.,
there is no pool data structure that would be responsible for managing pool
resources. Instead, it is managed in a distributed way. More precisely, at the
global level, for each pool, we track only the total amount of bonded or unbonded
Atoms and the current amount of issued shares. A share is a unit of Atom distribution
and the value of the share (share-to-atom exchange rate) changes during
system execution. The share-to-atom exchange rate can be computed as:
collection of Atoms contributed by different Atom holders. There are three
pools in the Staking module: the bonded, unbonding, and unbonded pool. Bonded
Atoms are part of the global bonded pool. If a validator or delegator wants to
unbond its Shares, these Shares are moved to the the unbonding pool for the
duration of the unbonding period. From here normally Atoms will be moved
directly into the delegators wallet, however under the situation thatn an
entire validator gets unbonded, the Atoms of the delegations will remain with
the validator and moved to the unbonded pool. For each pool, the total amount
of bonded, unbonding, or unbonded Atoms are tracked as well as the current
amount of issued pool-shares, the specific holdings of these shares by
validators are tracked in protocol by the validator object.
A share is a unit of Atom distribution and the value of the share
(share-to-atom exchange rate) can change during system execution. The
share-to-atom exchange rate can be computed as:
`share-to-atom-exchange-rate = size of the pool / ammount of issued shares`
Then for each validator candidate (in a per candidate data structure) we keep track of
the amount of shares the candidate owns in a pool. At any point in time,
the exact amount of Atoms a candidate has in the pool can be computed as the
number of shares it owns multiplied with the current share-to-atom exchange rate:
Then for each validator (in a per validator data structure) the protocol keeps
track of the amount of shares the validator owns in a pool. At any point in
time, the exact amount of Atoms a validator has in the pool can be computed as
the number of shares it owns multiplied with the current share-to-atom exchange
rate:
`candidate-coins = candidate.Shares * share-to-atom-exchange-rate`
`validator-coins = validator.Shares * share-to-atom-exchange-rate`
The benefit of such accounting of the pool resources is the fact that a
modification to the pool from bonding/unbonding/slashing/provisioning of
Atoms affects only global data (size of the pool and the number of shares) and
not the related validator/candidate data structure, i.e., the data structure of
other validators do not need to be modified. This has the advantage that
modifying global data is much cheaper computationally than modifying data of
every validator. Let's explain this further with several small examples:
The benefit of such accounting of the pool resources is the fact that a
modification to the pool from bonding/unbonding/slashing of Atoms affects only
global data (size of the pool and the number of shares) and not the related
validator data structure, i.e., the data structure of other validators do not
need to be modified. This has the advantage that modifying global data is much
cheaper computationally than modifying data of every validator. Let's explain
this further with several small examples:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXX TODO make way less verbose lets use bullet points to describe the example
XXX Also need to update to not include bonded atom provisions all atoms are
XXX redistributed with the fee pool now
We consider initially 4 validators p1, p2, p3 and p4, and that each validator
has bonded 10 Atoms to the bonded pool. Furthermore, let's assume that we have
@ -140,33 +165,38 @@ delegators (we will explain this in section X).
#### Delegator shares
A candidate is, depending on it's status, contributing Atoms to either the
bonded or unbonding pool, and in return gets some amount of (global) pool
shares. Note that not all those Atoms (and respective shares) are owned by the
candidate as some Atoms could be delegated to a candidate. The mechanism for
distribution of Atoms (and shares) between a candidate and it's delegators is
based on a notion of delegator shares. More precisely, every candidate is
issuing (local) delegator shares (`Candidate.IssuedDelegatorShares`) that
represents some portion of global shares managed by the candidate
(`Candidate.GlobalStakeShares`). The principle behind managing delegator shares
is the same as described in [Section](#The pool and the share). We now
A validator is, depending on its status, contributing Atoms to either the bond,
unbonding or unbonded pool - the validator in turn holds some amount of pool
shares. Not all of a validators Atoms (and respective shares) are owned by the
validator, some may be owned by delegators to that validator. The mechanism for
distribution of Atoms (and shares) between a validator and its delegators is
based on a notion of delegator shares. More precisely, every validator is
issuing (local) delegator shares (`Validator.IssuedDelegatorShares`) that
represents some portion of global shares managed by the validator
(`Validator.GlobalStakeShares`). The principle behind managing delegator shares
is the same as described in [Section](#The pool and the share). We now
illustrate it with an example.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXX TODO make way less verbose lets use bullet points to describe the example
XXX Also need to update to not include bonded atom provisions all atoms are
XXX redistributed with the fee pool now
Let's consider 4 validators p1, p2, p3 and p4, and assume that each validator
has bonded 10 Atoms to the bonded pool. Furthermore, let's assume that we have
issued initially 40 global shares, i.e., that
`share-to-atom-exchange-rate = 1 atom per share`. So we will set
`GlobalState.BondedPool = 40` and `GlobalState.BondedShares = 40` and in the
Candidate data structure of each validator `Candidate.GlobalStakeShares = 10`.
Validator data structure of each validator `Validator.GlobalStakeShares = 10`.
Furthermore, each validator issued 10 delegator shares which are initially
owned by itself, i.e., `Candidate.IssuedDelegatorShares = 10`, where
owned by itself, i.e., `Validator.IssuedDelegatorShares = 10`, where
`delegator-share-to-global-share-ex-rate = 1 global share per delegator share`.
Now lets assume that a delegator d1 delegates 5 atoms to a validator p1 and
consider what are the updates we need to make to the data structures. First,
`GlobalState.BondedPool = 45` and `GlobalState.BondedShares = 45`. Then, for
validator p1 we have `Candidate.GlobalStakeShares = 15`, but we also need to
validator p1 we have `Validator.GlobalStakeShares = 15`, but we also need to
issue also additional delegator shares, i.e.,
`Candidate.IssuedDelegatorShares = 15` as the delegator d1 now owns 5 delegator
`Validator.IssuedDelegatorShares = 15` as the delegator d1 now owns 5 delegator
shares of validator p1, where each delegator share is worth 1 global shares,
i.e, 1 Atom. Lets see now what happens after 5 new Atoms are created due to
inflation. In that case, we only need to update `GlobalState.BondedPool` which
@ -177,38 +207,3 @@ Therefore, a delegator d1 now owns:
`delegatorCoins = 5 (delegator shares) * 1 (delegator-share-to-global-share-ex-rate) * 50/45 (share-to-atom-ex-rate) = 5.55 Atoms`
### Inflation provisions
Validator provisions are minted on an hourly basis (the first block of a new
hour). The annual target of between 7% and 20%. The long-term target ratio of
bonded tokens to unbonded tokens is 67%.
The target annual inflation rate is recalculated for each provisions cycle. The
inflation is also subject to a rate change (positive or negative) depending on
the distance from the desired ratio (67%). The maximum rate change possible is
defined to be 13% per year, however the annual inflation is capped as between
7% and 20%.
```go
inflationRateChange(0) = 0
GlobalState.Inflation(0) = 0.07
bondedRatio = GlobalState.BondedPool / GlobalState.TotalSupply
AnnualInflationRateChange = (1 - bondedRatio / 0.67) * 0.13
annualInflation += AnnualInflationRateChange
if annualInflation > 0.20 then GlobalState.Inflation = 0.20
if annualInflation < 0.07 then GlobalState.Inflation = 0.07
provisionTokensHourly = GlobalState.TotalSupply * GlobalState.Inflation / (365.25*24)
```
Because the validators hold a relative bonded share (`GlobalStakeShares`), when
more bonded tokens are added proportionally to all validators, the only term
which needs to be updated is the `GlobalState.BondedPool`. So for each
provisions cycle:
```go
GlobalState.BondedPool += provisionTokensHourly
```

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@ -4,10 +4,10 @@
The staking module persists the following information to the store:
* `GlobalState`, a struct describing the global pools, inflation, and
fees
* `ValidatorCandidates: <pubkey | shares> => <candidate>`, a map of all candidates (including current validators) in the store,
* `ValidatorValidators: <pubkey | shares> => <validator>`, a map of all validators (including current validators) in the store,
indexed by their public key and shares in the global pool.
* `DelegatorBonds: < delegator-address | candidate-pubkey > => <delegator-bond>`. a map of all delegations by a delegator to a candidate,
indexed by delegator address and candidate pubkey.
* `DelegatorBonds: < delegator-address | validator-pubkey > => <delegator-bond>`. a map of all delegations by a delegator to a validator,
indexed by delegator address and validator pubkey.
public key
* `UnbondQueue`, the queue of unbonding delegations
* `RedelegateQueue`, the queue of re-delegations
@ -25,7 +25,7 @@ type GlobalState struct {
TotalSupply int64 // total supply of Atoms
BondedPool int64 // reserve of bonded tokens
BondedShares rational.Rat // sum of all shares distributed for the BondedPool
UnbondedPool int64 // reserve of unbonding tokens held with candidates
UnbondedPool int64 // reserve of unbonding tokens held with validators
UnbondedShares rational.Rat // sum of all shares distributed for the UnbondedPool
InflationLastTime int64 // timestamp of last processing of inflation
Inflation rational.Rat // current annual inflation rate
@ -57,22 +57,22 @@ type Params struct {
}
```
### Candidate
### Validator
The `Candidate` holds the current state and some historical
actions of validators or candidate-validators.
The `Validator` holds the current state and some historical
actions of validators.
``` go
type CandidateStatus byte
type ValidatorStatus byte
const (
Bonded CandidateStatus = 0x01
Unbonded CandidateStatus = 0x02
Revoked CandidateStatus = 0x03
Bonded ValidatorStatus = 0x01
Unbonded ValidatorStatus = 0x02
Revoked ValidatorStatus = 0x03
)
type Candidate struct {
Status CandidateStatus
type Validator struct {
Status ValidatorStatus
ConsensusPubKey crypto.PubKey
GovernancePubKey crypto.PubKey
Owner crypto.Address
@ -98,30 +98,30 @@ type Description struct {
}
```
Candidate parameters are described:
* Status: it can be Bonded (active validator), Unbonding (validator candidate)
Validator parameters are described:
* Status: it can be Bonded (active validator), Unbonding (validator)
or Revoked
* ConsensusPubKey: candidate public key that is used strictly for participating in
* ConsensusPubKey: validator public key that is used strictly for participating in
consensus
* GovernancePubKey: public key used by the validator for governance voting
* Owner: Address that is allowed to unbond coins.
* GlobalStakeShares: Represents shares of `GlobalState.BondedPool` if
`Candidate.Status` is `Bonded`; or shares of `GlobalState.Unbondingt Pool`
`Validator.Status` is `Bonded`; or shares of `GlobalState.Unbondingt Pool`
otherwise
* IssuedDelegatorShares: Sum of all shares a candidate issued to delegators
(which includes the candidate's self-bond); a delegator share represents
their stake in the Candidate's `GlobalStakeShares`
* IssuedDelegatorShares: Sum of all shares a validator issued to delegators
(which includes the validator's self-bond); a delegator share represents
their stake in the Validator's `GlobalStakeShares`
* RedelegatingShares: The portion of `IssuedDelegatorShares` which are
currently re-delegating to a new validator
* VotingPower: Proportional to the amount of bonded tokens which the validator
has if `Candidate.Status` is `Bonded`; otherwise it is equal to `0`
has if `Validator.Status` is `Bonded`; otherwise it is equal to `0`
* Commission: The commission rate of fees charged to any delegators
* CommissionMax: The maximum commission rate this candidate can charge each
* CommissionMax: The maximum commission rate this validator can charge each
day from the date `GlobalState.DateLastCommissionReset`
* CommissionChangeRate: The maximum daily increase of the candidate commission
* CommissionChangeRate: The maximum daily increase of the validator commission
* CommissionChangeToday: Counter for the amount of change to commission rate
which has occurred today, reset on the first block of each day (UTC time)
* ProposerRewardPool: reward pool for extra fees collected when this candidate
* ProposerRewardPool: reward pool for extra fees collected when this validator
is the proposer of a block
* Adjustment factor used to passively calculate each validators entitled fees
from `GlobalState.FeePool`
@ -135,14 +135,14 @@ Candidate parameters are described:
### DelegatorBond
Atom holders may delegate coins to candidates; under this circumstance their
Atom holders may delegate coins to validators; under this circumstance their
funds are held in a `DelegatorBond` data structure. It is owned by one
delegator, and is associated with the shares for one candidate. The sender of
delegator, and is associated with the shares for one validator. The sender of
the transaction is the owner of the bond.
``` go
type DelegatorBond struct {
Candidate crypto.PubKey
Validator crypto.PubKey
Shares rational.Rat
AdjustmentFeePool coin.Coins
AdjustmentRewardPool coin.Coins
@ -150,12 +150,12 @@ type DelegatorBond struct {
```
Description:
* Candidate: the public key of the validator candidate: bonding too
* Shares: the number of delegator shares received from the validator candidate
* Validator: the public key of the validator: bonding too
* Shares: the number of delegator shares received from the validator
* AdjustmentFeePool: Adjustment factor used to passively calculate each bonds
entitled fees from `GlobalState.FeePool`
* AdjustmentRewardPool: Adjustment factor used to passively calculate each
bonds entitled fees from `Candidate.ProposerRewardPool`
bonds entitled fees from `Validator.ProposerRewardPool`
### QueueElem
@ -165,7 +165,7 @@ data structure. All queue elements share a common structure:
```golang
type QueueElem struct {
Candidate crypto.PubKey
Validator crypto.PubKey
InitTime int64 // when the element was added to the queue
}
```
@ -185,7 +185,7 @@ type QueueElemUnbondDelegation struct {
QueueElem
Payout Address // account to pay out to
Tokens coin.Coins // the value in Atoms of the amount of delegator shares which are unbonding
StartSlashRatio rational.Rat // candidate slash ratio
StartSlashRatio rational.Rat // validator slash ratio
}
```
@ -198,7 +198,7 @@ type QueueElemReDelegate struct {
QueueElem
Payout Address // account to pay out to
Shares rational.Rat // amount of shares which are unbonding
NewCandidate crypto.PubKey // validator to bond to after unbond
NewValidator crypto.PubKey // validator to bond to after unbond
}
```

View File

@ -18,8 +18,8 @@ reference to the queue of unbond delegations, `reDelegationQueue` is the
reference for the queue of redelegations. We use `tx` to denote a
reference to a transaction that is being processed, and `sender` to denote the
address of the sender of the transaction. We use function
`loadCandidate(store, PubKey)` to obtain a Candidate structure from the store,
and `saveCandidate(store, candidate)` to save it. Similarly, we use
`loadValidator(store, PubKey)` to obtain a Validator structure from the store,
and `saveValidator(store, validator)` to save it. Similarly, we use
`loadDelegatorBond(store, sender, PubKey)` to load a delegator bond with the
key (sender and PubKey) from the store, and
`saveDelegatorBond(store, sender, bond)` to save it.
@ -42,23 +42,23 @@ type TxDeclareCandidacy struct {
}
declareCandidacy(tx TxDeclareCandidacy):
candidate = loadCandidate(store, tx.PubKey)
if candidate != nil return // candidate with that public key already exists
validator = loadValidator(store, tx.PubKey)
if validator != nil return // validator with that public key already exists
candidate = NewCandidate(tx.PubKey)
candidate.Status = Unbonded
candidate.Owner = sender
init candidate VotingPower, GlobalStakeShares, IssuedDelegatorShares, RedelegatingShares and Adjustment to rational.Zero
validator = NewValidator(tx.PubKey)
validator.Status = Unbonded
validator.Owner = sender
init validator VotingPower, GlobalStakeShares, IssuedDelegatorShares, RedelegatingShares and Adjustment to rational.Zero
init commision related fields based on the values from tx
candidate.ProposerRewardPool = Coin(0)
candidate.Description = tx.Description
validator.ProposerRewardPool = Coin(0)
validator.Description = tx.Description
saveCandidate(store, candidate)
saveValidator(store, validator)
txDelegate = TxDelegate(tx.PubKey, tx.Amount)
return delegateWithCandidate(txDelegate, candidate)
return delegateWithValidator(txDelegate, validator)
// see delegateWithCandidate function in [TxDelegate](TxDelegate)
// see delegateWithValidator function in [TxDelegate](TxDelegate)
```
### TxEditCandidacy
@ -75,14 +75,14 @@ type TxEditCandidacy struct {
}
editCandidacy(tx TxEditCandidacy):
candidate = loadCandidate(store, tx.PubKey)
if candidate == nil or candidate.Status == Revoked return
validator = loadValidator(store, tx.PubKey)
if validator == nil or validator.Status == Revoked return
if tx.GovernancePubKey != nil candidate.GovernancePubKey = tx.GovernancePubKey
if tx.Commission >= 0 candidate.Commission = tx.Commission
if tx.Description != nil candidate.Description = tx.Description
if tx.GovernancePubKey != nil validator.GovernancePubKey = tx.GovernancePubKey
if tx.Commission >= 0 validator.Commission = tx.Commission
if tx.Description != nil validator.Description = tx.Description
saveCandidate(store, candidate)
saveValidator(store, validator)
return
```
@ -90,7 +90,7 @@ editCandidacy(tx TxEditCandidacy):
Delegator bonds are created using the `TxDelegate` transaction. Within this
transaction the delegator provides an amount of coins, and in return receives
some amount of candidate's delegator shares that are assigned to
some amount of validator's delegator shares that are assigned to
`DelegatorBond.Shares`.
```golang
@ -100,14 +100,14 @@ type TxDelegate struct {
}
delegate(tx TxDelegate):
candidate = loadCandidate(store, tx.PubKey)
if candidate == nil return
return delegateWithCandidate(tx, candidate)
validator = loadValidator(store, tx.PubKey)
if validator == nil return
return delegateWithValidator(tx, validator)
delegateWithCandidate(tx TxDelegate, candidate Candidate):
if candidate.Status == Revoked return
delegateWithValidator(tx TxDelegate, validator Validator):
if validator.Status == Revoked return
if candidate.Status == Bonded
if validator.Status == Bonded
poolAccount = params.HoldBonded
else
poolAccount = params.HoldUnbonded
@ -118,16 +118,16 @@ delegateWithCandidate(tx TxDelegate, candidate Candidate):
bond = loadDelegatorBond(store, sender, tx.PubKey)
if bond == nil then bond = DelegatorBond(tx.PubKey, rational.Zero, Coin(0), Coin(0))
issuedDelegatorShares = addTokens(tx.Amount, candidate)
issuedDelegatorShares = addTokens(tx.Amount, validator)
bond.Shares += issuedDelegatorShares
saveCandidate(store, candidate)
saveValidator(store, validator)
saveDelegatorBond(store, sender, bond)
saveGlobalState(store, gs)
return
addTokens(amount coin.Coin, candidate Candidate):
if candidate.Status == Bonded
addTokens(amount coin.Coin, validator Validator):
if validator.Status == Bonded
gs.BondedPool += amount
issuedShares = amount / exchangeRate(gs.BondedShares, gs.BondedPool)
gs.BondedShares += issuedShares
@ -136,15 +136,15 @@ addTokens(amount coin.Coin, candidate Candidate):
issuedShares = amount / exchangeRate(gs.UnbondedShares, gs.UnbondedPool)
gs.UnbondedShares += issuedShares
candidate.GlobalStakeShares += issuedShares
validator.GlobalStakeShares += issuedShares
if candidate.IssuedDelegatorShares.IsZero()
if validator.IssuedDelegatorShares.IsZero()
exRate = rational.One
else
exRate = candidate.GlobalStakeShares / candidate.IssuedDelegatorShares
exRate = validator.GlobalStakeShares / validator.IssuedDelegatorShares
issuedDelegatorShares = issuedShares / exRate
candidate.IssuedDelegatorShares += issuedDelegatorShares
validator.IssuedDelegatorShares += issuedDelegatorShares
return issuedDelegatorShares
exchangeRate(shares rational.Rat, tokenAmount int64):
@ -170,20 +170,20 @@ unbond(tx TxUnbond):
bond.Shares -= tx.Shares
candidate = loadCandidate(store, tx.PubKey)
validator = loadValidator(store, tx.PubKey)
revokeCandidacy = false
if bond.Shares.IsZero()
if sender == candidate.Owner and candidate.Status != Revoked then revokeCandidacy = true then removeDelegatorBond(store, sender, bond)
if sender == validator.Owner and validator.Status != Revoked then revokeCandidacy = true then removeDelegatorBond(store, sender, bond)
else
saveDelegatorBond(store, sender, bond)
if candidate.Status == Bonded
if validator.Status == Bonded
poolAccount = params.HoldBonded
else
poolAccount = params.HoldUnbonded
returnedCoins = removeShares(candidate, shares)
returnedCoins = removeShares(validator, shares)
unbondDelegationElem = QueueElemUnbondDelegation(tx.PubKey, currentHeight(), sender, returnedCoins, startSlashRatio)
unbondDelegationQueue.add(unbondDelegationElem)
@ -191,21 +191,21 @@ unbond(tx TxUnbond):
transfer(poolAccount, unbondingPoolAddress, returnCoins)
if revokeCandidacy
if candidate.Status == Bonded then bondedToUnbondedPool(candidate)
candidate.Status = Revoked
if validator.Status == Bonded then bondedToUnbondedPool(validator)
validator.Status = Revoked
if candidate.IssuedDelegatorShares.IsZero()
removeCandidate(store, tx.PubKey)
if validator.IssuedDelegatorShares.IsZero()
removeValidator(store, tx.PubKey)
else
saveCandidate(store, candidate)
saveValidator(store, validator)
saveGlobalState(store, gs)
return
removeShares(candidate Candidate, shares rational.Rat):
globalPoolSharesToRemove = delegatorShareExRate(candidate) * shares
removeShares(validator Validator, shares rational.Rat):
globalPoolSharesToRemove = delegatorShareExRate(validator) * shares
if candidate.Status == Bonded
if validator.Status == Bonded
gs.BondedShares -= globalPoolSharesToRemove
removedTokens = exchangeRate(gs.BondedShares, gs.BondedPool) * globalPoolSharesToRemove
gs.BondedPool -= removedTokens
@ -214,25 +214,25 @@ removeShares(candidate Candidate, shares rational.Rat):
removedTokens = exchangeRate(gs.UnbondedShares, gs.UnbondedPool) * globalPoolSharesToRemove
gs.UnbondedPool -= removedTokens
candidate.GlobalStakeShares -= removedTokens
candidate.IssuedDelegatorShares -= shares
validator.GlobalStakeShares -= removedTokens
validator.IssuedDelegatorShares -= shares
return returnedCoins
delegatorShareExRate(candidate Candidate):
if candidate.IssuedDelegatorShares.IsZero() then return rational.One
return candidate.GlobalStakeShares / candidate.IssuedDelegatorShares
delegatorShareExRate(validator Validator):
if validator.IssuedDelegatorShares.IsZero() then return rational.One
return validator.GlobalStakeShares / validator.IssuedDelegatorShares
bondedToUnbondedPool(candidate Candidate):
removedTokens = exchangeRate(gs.BondedShares, gs.BondedPool) * candidate.GlobalStakeShares
gs.BondedShares -= candidate.GlobalStakeShares
bondedToUnbondedPool(validator Validator):
removedTokens = exchangeRate(gs.BondedShares, gs.BondedPool) * validator.GlobalStakeShares
gs.BondedShares -= validator.GlobalStakeShares
gs.BondedPool -= removedTokens
gs.UnbondedPool += removedTokens
issuedShares = removedTokens / exchangeRate(gs.UnbondedShares, gs.UnbondedPool)
gs.UnbondedShares += issuedShares
candidate.GlobalStakeShares = issuedShares
candidate.Status = Unbonded
validator.GlobalStakeShares = issuedShares
validator.Status = Unbonded
return transfer(address of the bonded pool, address of the unbonded pool, removedTokens)
```
@ -254,10 +254,10 @@ redelegate(tx TxRedelegate):
if bond == nil then return
if bond.Shares < tx.Shares return
candidate = loadCandidate(store, tx.PubKeyFrom)
if candidate == nil return
validator = loadValidator(store, tx.PubKeyFrom)
if validator == nil return
candidate.RedelegatingShares += tx.Shares
validator.RedelegatingShares += tx.Shares
reDelegationElem = QueueElemReDelegate(tx.PubKeyFrom, currentHeight(), sender, tx.Shares, tx.PubKeyTo)
redelegationQueue.add(reDelegationElem)
return

View File

@ -36,10 +36,10 @@ tick(ctx Context):
if time > reDelegationQueue.head().InitTime + UnbondingPeriod
for each element elem in the unbondDelegationQueue where time > elem.InitTime + UnbondingPeriod do
candidate = getCandidate(store, elem.PubKey)
returnedCoins = removeShares(candidate, elem.Shares)
candidate.RedelegatingShares -= elem.Shares
delegateWithCandidate(TxDelegate(elem.NewCandidate, returnedCoins), candidate)
validator = getValidator(store, elem.PubKey)
returnedCoins = removeShares(validator, elem.Shares)
validator.RedelegatingShares -= elem.Shares
delegateWithValidator(TxDelegate(elem.NewValidator, returnedCoins), validator)
reDelegationQueue.remove(elem)
return UpdateValidatorSet()
@ -61,42 +61,42 @@ nextInflation(hrsPerYr rational.Rat):
return inflation
UpdateValidatorSet():
candidates = loadCandidates(store)
validators = loadValidators(store)
v1 = candidates.Validators()
v2 = updateVotingPower(candidates).Validators()
v1 = validators.Validators()
v2 = updateVotingPower(validators).Validators()
change = v1.validatorsUpdated(v2) // determine all updated validators between two validator sets
return change
updateVotingPower(candidates Candidates):
foreach candidate in candidates do
candidate.VotingPower = (candidate.IssuedDelegatorShares - candidate.RedelegatingShares) * delegatorShareExRate(candidate)
updateVotingPower(validators Validators):
foreach validator in validators do
validator.VotingPower = (validator.IssuedDelegatorShares - validator.RedelegatingShares) * delegatorShareExRate(validator)
candidates.Sort()
validators.Sort()
foreach candidate in candidates do
if candidate is not in the first params.MaxVals
candidate.VotingPower = rational.Zero
if candidate.Status == Bonded then bondedToUnbondedPool(candidate Candidate)
foreach validator in validators do
if validator is not in the first params.MaxVals
validator.VotingPower = rational.Zero
if validator.Status == Bonded then bondedToUnbondedPool(validator Validator)
else if candidate.Status == UnBonded then unbondedToBondedPool(candidate)
else if validator.Status == UnBonded then unbondedToBondedPool(validator)
saveCandidate(store, c)
saveValidator(store, c)
return candidates
return validators
unbondedToBondedPool(candidate Candidate):
removedTokens = exchangeRate(gs.UnbondedShares, gs.UnbondedPool) * candidate.GlobalStakeShares
gs.UnbondedShares -= candidate.GlobalStakeShares
unbondedToBondedPool(validator Validator):
removedTokens = exchangeRate(gs.UnbondedShares, gs.UnbondedPool) * validator.GlobalStakeShares
gs.UnbondedShares -= validator.GlobalStakeShares
gs.UnbondedPool -= removedTokens
gs.BondedPool += removedTokens
issuedShares = removedTokens / exchangeRate(gs.BondedShares, gs.BondedPool)
gs.BondedShares += issuedShares
candidate.GlobalStakeShares = issuedShares
candidate.Status = Bonded
validator.GlobalStakeShares = issuedShares
validator.Status = Bonded
return transfer(address of the unbonded pool, address of the bonded pool, removedTokens)
```
@ -151,7 +151,7 @@ LastCommit and +2/3 (see [TODO](https://github.com/cosmos/cosmos-sdk/issues/967)
Validators are penalized for failing to be included in the LastCommit for some
number of blocks by being automatically unbonded.
The following information is stored with each validator candidate, and is only non-zero if the candidate becomes an active validator:
The following information is stored with each validator, and is only non-zero if the validator becomes an active validator:
```go
type ValidatorSigningInfo struct {
@ -161,7 +161,7 @@ type ValidatorSigningInfo struct {
```
Where:
* `StartHeight` is set to the height that the candidate became an active validator (with non-zero voting power).
* `StartHeight` is set to the height that the validator became an active validator (with non-zero voting power).
* `SignedBlocksBitArray` is a bit-array of size `SIGNED_BLOCKS_WINDOW` that records, for each of the last `SIGNED_BLOCKS_WINDOW` blocks,
whether or not this validator was included in the LastCommit. It uses a `0` if the validator was included, and a `1` if it was not.
Note it is initialized with all 0s.