State
Pool
Pool is used for tracking bonded and not-bonded token supply of the bond denomination.
LastTotalPower
LastTotalPower tracks the total amounts of bonded tokens recorded during the previous end block. Store entries prefixed with "Last" must remain unchanged until EndBlock.
- LastTotalPower:
0x12 -> ProtocolBuffer(sdkmath.Int)
Params
Params is a module-wide configuration structure that stores system parameters and defines overall functioning of the staking module.
- Params:
Paramsspace("staking") -> legacy_amino(params)
Validator
Validators can have one of three statuses
Unbonded: The validator is not in the active set. They cannot sign blocks and do not earn rewards. They can receive delegations.Bonded: Once the validator receives sufficient bonded tokens they automtically join the active set duringEndBlockand their status is updated toBonded. They are signing blocks and receiving rewards. They can receive further delegations. They can be slashed for misbehavior. Delegators to this validator who unbond their delegation must wait the duration of the UnbondingTime, a chain-specific param, during which time they are still slashable for offences of the source validator if those offences were committed during the period of time that the tokens were bonded.Unbonding: When a validator leaves the active set, either by choice or due to slashing, jailing or tombstoning, an unbonding of all their delegations begins. All delegations must then wait the UnbondingTime before their tokens are moved to their accounts from theBondedPool.
Validators objects should be primarily stored and accessed by the
OperatorAddr, an SDK validator address for the operator of the validator. Two
additional indices are maintained per validator object in order to fulfill
required lookups for slashing and validator-set updates. A third special index
(LastValidatorPower) is also maintained which however remains constant
throughout each block, unlike the first two indices which mirror the validator
records within a block.
- Validators:
0x21 | OperatorAddrLen (1 byte) | OperatorAddr -> ProtocolBuffer(validator) - ValidatorsByConsAddr:
0x22 | ConsAddrLen (1 byte) | ConsAddr -> OperatorAddr - ValidatorsByPower:
0x23 | BigEndian(ConsensusPower) | OperatorAddrLen (1 byte) | OperatorAddr -> OperatorAddr - LastValidatorsPower:
0x11 | OperatorAddrLen (1 byte) | OperatorAddr -> ProtocolBuffer(ConsensusPower)
Validators is the primary index - it ensures that each operator can have only one
associated validator, where the public key of that validator can change in the
future. Delegators can refer to the immutable operator of the validator, without
concern for the changing public key.
ValidatorByConsAddr is an additional index that enables lookups for slashing.
When Tendermint reports evidence, it provides the validator address, so this
map is needed to find the operator. Note that the ConsAddr corresponds to the
address which can be derived from the validator's ConsPubKey.
ValidatorsByPower is an additional index that provides a sorted list of
potential validators to quickly determine the current active set. Here
ConsensusPower is validator.Tokens/10^6 by default. Note that all validators
where Jailed is true are not stored within this index.
LastValidatorsPower is a special index that provides a historical list of the
last-block's bonded validators. This index remains constant during a block but
is updated during the validator set update process which takes place in EndBlock.
Each validator's state is stored in a Validator struct:
+++ https://github.com/cosmos/cosmos-sdk/blob/v0.40.0/proto/cosmos/staking/v1beta1/staking.proto#L65-L99
+++ https://github.com/cosmos/cosmos-sdk/blob/v0.40.0/proto/cosmos/staking/v1beta1/staking.proto#L24-L63
Delegation
Delegations are identified by combining DelegatorAddr (the address of the delegator)
with the ValidatorAddr Delegators are indexed in the store as follows:
- Delegation:
0x31 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValidatorAddrLen (1 byte) | ValidatorAddr -> ProtocolBuffer(delegation)
Stake holders may delegate coins to validators; under this circumstance their
funds are held in a Delegation data structure. It is owned by one
delegator, and is associated with the shares for one validator. The sender of
the transaction is the owner of the bond.
Delegator Shares
When one Delegates tokens to a Validator they are issued a number of delegator shares based on a dynamic exchange rate, calculated as follows from the total number of tokens delegated to the validator and the number of shares issued so far:
Shares per Token = validator.TotalShares() / validator.Tokens()
Only the number of shares received is stored on the DelegationEntry. When a delegator then Undelegates, the token amount they receive is calculated from the number of shares they currently hold and the inverse exchange rate:
Tokens per Share = validator.Tokens() / validatorShares()
These Shares are simply an accounting mechanism. They are not a fungible asset. The reason for
this mechanism is to simplify the accounting around slashing. Rather than iteratively slashing the
tokens of every delegation entry, instead the Validators total bonded tokens can be slashed,
effectively reducing the value of each issued delegator share.
UnbondingDelegation
Shares in a Delegation can be unbonded, but they must for some time exist as
an UnbondingDelegation, where shares can be reduced if Byzantine behavior is
detected.
UnbondingDelegation are indexed in the store as:
- UnbondingDelegation:
0x32 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValidatorAddrLen (1 byte) | ValidatorAddr -> ProtocolBuffer(unbondingDelegation) - UnbondingDelegationsFromValidator:
0x33 | ValidatorAddrLen (1 byte) | ValidatorAddr | DelegatorAddrLen (1 byte) | DelegatorAddr -> nil
The first map here is used in queries, to lookup all unbonding delegations for a given delegator, while the second map is used in slashing, to lookup all unbonding delegations associated with a given validator that need to be slashed.
A UnbondingDelegation object is created every time an unbonding is initiated.
Redelegation
The bonded tokens worth of a Delegation may be instantly redelegated from a
source validator to a different validator (destination validator). However when
this occurs they must be tracked in a Redelegation object, whereby their
shares can be slashed if their tokens have contributed to a Byzantine fault
committed by the source validator.
Redelegation are indexed in the store as:
- Redelegations:
0x34 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValidatorAddrLen (1 byte) | ValidatorSrcAddr | ValidatorDstAddr -> ProtocolBuffer(redelegation) - RedelegationsBySrc:
0x35 | ValidatorSrcAddrLen (1 byte) | ValidatorSrcAddr | ValidatorDstAddrLen (1 byte) | ValidatorDstAddr | DelegatorAddrLen (1 byte) | DelegatorAddr -> nil - RedelegationsByDst:
0x36 | ValidatorDstAddrLen (1 byte) | ValidatorDstAddr | ValidatorSrcAddrLen (1 byte) | ValidatorSrcAddr | DelegatorAddrLen (1 byte) | DelegatorAddr -> nil
The first map here is used for queries, to lookup all redelegations for a given
delegator. The second map is used for slashing based on the ValidatorSrcAddr,
while the third map is for slashing based on the ValidatorDstAddr.
A redelegation object is created every time a redelegation occurs. To prevent "redelegation hopping" redelegations may not occur under the situation that:
- the (re)delegator already has another immature redelegation in progress
with a destination to a validator (let's call it
Validator X) - and, the (re)delegator is attempting to create a new redelegation
where the source validator for this new redelegation is
Validator X.
Queues
All queues objects are sorted by timestamp. The time used within any queue is
first rounded to the nearest nanosecond then sorted. The sortable time format
used is a slight modification of the RFC3339Nano and uses the the format string
"2006-01-02T15:04:05.000000000". Notably this format:
- right pads all zeros
- drops the time zone info (uses UTC)
In all cases, the stored timestamp represents the maturation time of the queue element.
UnbondingDelegationQueue
For the purpose of tracking progress of unbonding delegations the unbonding delegations queue is kept.
- UnbondingDelegation:
0x41 | format(time) -> []DVPair
RedelegationQueue
For the purpose of tracking progress of redelegations the redelegation queue is kept.
- RedelegationQueue:
0x42 | format(time) -> []DVVTriplet
ValidatorQueue
For the purpose of tracking progress of unbonding validators the validator queue is kept.
- ValidatorQueueTime:
0x43 | format(time) -> []sdk.ValAddress
The stored object as each key is an array of validator operator addresses from which the validator object can be accessed. Typically it is expected that only a single validator record will be associated with a given timestamp however it is possible that multiple validators exist in the queue at the same location.
HistoricalInfo
HistoricalInfo objects are stored and pruned at each block such that the staking keeper persists
the n most recent historical info defined by staking module parameter: HistoricalEntries.
+++ https://github.com/cosmos/cosmos-sdk/blob/v0.40.0/proto/cosmos/staking/v1beta1/staking.proto#L15-L22
At each BeginBlock, the staking keeper will persist the current Header and the Validators that committed
the current block in a HistoricalInfo object. The Validators are sorted on their address to ensure that
they are in a determisnistic order.
The oldest HistoricalEntries will be pruned to ensure that there only exist the parameter-defined number of
historical entries.