Struct TabletDescriptor 

pub struct TabletDescriptor {
    pub tablet_id: TabletId,
    pub table_id: TableId,
    pub database_id: DatabaseId,
    pub raft_group_id: RaftGroupId,
    pub partition: PartitionBounds,
    pub replicas: Vec<ReplicaDescriptor>,
    pub leader_hint: Option<NodeId>,
    pub generation: u64,
    pub state: TabletState,
}

One independently replicated data partition (spec section 12.1).

generation advances at every atomic descriptor publication (split, merge, move); every request carries the generation it was routed with, and a mismatch is classified by check_generation.

Publication generation rules (spec sections 12.5-12.6; the protocols live in crate::split and crate::merge):

• Split: the source is marked TabletState::Splitting at g + 1 (g = the pre-split generation); the children are created Creating at g + 1 and are never routed to; the atomic routing publication assigns one new generation p = (source generation at publication) + 1, taking the children Creating -> Active and the source Splitting -> Retiring together. A request holding g against the splitting source is classified RoutingError::TabletSplit; after publication any generation below p against the retiring source is RoutingError::TabletMoved.
• Merge: each source is marked TabletState::Merging at its own g + 1; the publication generation is p = max(sources' generations at publication) + 1, assigned to the replacement (Creating -> Active) and to both sources (Merging -> Retiring) in one atomic command.
• Source removal publishes Retiring -> Retired at p + 1 before the descriptor is deleted.

Fields

tablet_id: TabletId

The tablet’s identity.

table_id: TableId

Table the tablet belongs to.

database_id: DatabaseId

Logical database owning the table (meta-resolved). When zero on a legacy descriptor, the runtime resolves via meta table_id → database_id before falling back to a deterministic raft-group-derived id for pre-metadata tablets only.

raft_group_id: RaftGroupId

Raft group replicating the tablet.

partition: PartitionBounds

Key range the tablet covers.

replicas: Vec<ReplicaDescriptor>

All replicas (voters and learners), on distinct nodes.

leader_hint: Option<NodeId>

Last known leader, when the meta plane has observed one.

generation: u64

Descriptor generation; bumped by every atomic publication.

state: TabletState

Lifecycle state; transitions go through Self::try_transition.

Implementations

impl TabletDescriptor

pub fn validate(&self) -> Result<(), TabletError>

Structural validation: reserved identifiers, well-formed bounds, distinct replica nodes and Raft ids, a leader hint that names a replica, and at least one voter outside TabletState::Creating.

pub fn voters(&self) -> impl Iterator<Item = &ReplicaDescriptor>

The voter replicas.

pub fn learners(&self) -> impl Iterator<Item = &ReplicaDescriptor>

The learner replicas.

pub fn voter_count(&self) -> usize

Number of voting replicas.

pub fn replica_on(&self, node: NodeId) -> Option<&ReplicaDescriptor>

The replica on node, if any.

pub fn try_transition(&mut self, next: TabletState) -> Result<(), TabletError>

Transitions to next, enforcing the TabletState graph. Generation bumps are the meta group’s business — this changes only the state.

pub fn published_transition( &self, next: TabletState, ) -> Result<Self, TabletError>

A copy of the descriptor transitioned to next with the generation bumped by one: the shape of one atomic descriptor publication (see the publication generation rules on TabletDescriptor). The descriptor itself is unchanged, so the caller stages the published form and the meta plane applies it last-writer-wins.

Trait Implementations

impl Clone for TabletDescriptor

fn clone(&self) -> TabletDescriptor

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TabletDescriptor

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TabletDescriptor

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for TabletDescriptor

impl PartialEq for TabletDescriptor

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for TabletDescriptor

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for TabletDescriptor