Struct ConsensusConstants 

pub struct ConsensusConstants {

    pub block_confirmation_depth: BlockNumber,
    pub shard_confirmation_depth: BlockNumber,
    pub block_authoring_delay: SlotNumber,
    pub pot: PotConsensusConstants,
    pub retarget_interval: BlockNumber,
    pub slot_probability: (u64, u64),
    pub slot_duration: SlotDuration,
    pub recent_segments: HistorySize,
    pub recent_history_fraction: (HistorySize, HistorySize),
    pub min_sector_lifetime: HistorySize,
    pub max_block_timestamp_drift: BlockTimestamp,
    pub shard_rotation_interval: BlockNumber,
    pub shard_rotation_delay: BlockNumber,
}

Consensus constants

Fields

block_confirmation_depth: BlockNumber

Depth at which a block is confirmed and enters the recorded history.

When block n is built, the block at n - block_confirmation_depth is confirmed, so the largest possible reorg is block_confirmation_depth - 1 blocks. Importing the next best block (block number best_number + 1) confirms the block at best_number + 1 - block_confirmation_depth, so fork blocks must be above it, and blocks up to it are the same on every chain that can still be extended. This is why they can be referenced by block number alone.

With block_confirmation_depth = 5 and shard_confirmation_depth = 2:

block number
best_number + 1  next best block
best_number      best block
best_number - 3  deepest fork blocks
best_number - 4  confirmed once the next best block is imported  -+ read by the super
best_number - 5  confirmed                                        | segment derivation of
best_number - 6  confirmed                                       -+ the next best block

The block lifecycle in the database is shown on ClientDatabaseOptions in ab-client-database.

This is from the perspective of the individual shard, with additional confirmation on the beacon chain required for intermediate and leaf shards (see shard_confirmation_depth).

shard_confirmation_depth: BlockNumber

Depth on the beacon chain in addition to block_confirmation_depth after intermediate or leaf shard information on the beacon chain is confirmed and corresponding segment roots become a part of the super segment.

Segment roots included in the beacon chain block at n - block_confirmation_depth - shard_confirmation_depth become a part of the super segment of block n unless later beacon chain blocks up to n - block_confirmation_depth show that their shard reorged them (see the diagram on block_confirmation_depth).

This is separate from the block confirmation on the corresponding shard itself, which happens much sooner (see block_confirmation_depth), but can’t be immediately trusted by the beacon chain.

block_authoring_delay: SlotNumber

Number of slots between slot arrival and when the corresponding block can be produced

pot: PotConsensusConstants

Proof-of-time consensus constants

retarget_interval: BlockNumber

Period of time in blocks after which the solution range is adjusted

slot_probability: (u64, u64)

Slot probability

slot_duration: SlotDuration

The slot duration in milliseconds

recent_segments: HistorySize

Number of latest archived segments that are considered “recent history”

recent_history_fraction: (HistorySize, HistorySize)

Fraction of pieces from the “recent history” (recent_segments) in each sector

min_sector_lifetime: HistorySize

Minimum lifetime of a plotted sector, measured in archived segments

max_block_timestamp_drift: BlockTimestamp

Max block timestamp drift allowed

shard_rotation_interval: BlockNumber

Number of beacon chain blocks between shard rotations.

Every this number of beacon chain blocks PoT entropy is taken to calculate the next shard assignment.

shard_rotation_delay: BlockNumber

Delay in beacon chain blocks for the next shard rotation.

Delay after shard assignment is revealed before it actually takes effect (essentially the amount of time for a node to sync the corresponding shard).

Trait Implementations

impl Clone for ConsensusConstants

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for ConsensusConstants

impl Debug for ConsensusConstants

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for ConsensusConstants

impl PartialEq for ConsensusConstants

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ConsensusConstants