Enum Update 

pub enum Update {
    Hydrated {
        tx_id: TxId,
        changes: Vec<ChangeEvent>,
    },
    Changed {
        tx_id: TxId,
        changes: Vec<ChangeEvent>,
    },
    PartitionHydrated {
        tx_id: TxId,
        binding: Binding,
        changes: Vec<ChangeEvent>,
    },
}

A query baseline or incremental changes. A Hydrated contains the full result as Add events and replaces any previous baseline. Changed contains deltas to apply in order. Delivery depends on the runtime:

• Db calls subscribers with Changed after the SQL commit.
• Cluster can emit several provisional Changed slices for one transaction, before commit. Stage them until the hosting worker’s ClusterEvent::Progressed.

Hydrated can fire AGAIN after a delta-overflow shed (design 306 D4): a transaction whose folded rows outgrow the derivation memory budget still commits, but it cannot be derived incrementally — the engine rebuilds and every query re-hydrates from the committed state. A re-delivered Hydrated REPLACES the subscriber’s entire view state (drop what you hold, apply the Adds); it is the single-thread Db’s analogue of the cluster’s Faulted → re-register → re-hydrate cycle, folded into the existing subscription.

Variants

Hydrated

Fields

tx_id: TxId

changes: Vec<ChangeEvent>

Changed

Fields

tx_id: TxId

changes: Vec<ChangeEvent>

PartitionHydrated

One partition of a parameterized query family hydrated (design 310 §5.2 / impl plan D8): the initial Add set for binding, tagged with the committed watermark it reflects — emitted once per bound partition (at family registration, and again for every later bind) in place of the singleton’s Hydrated. A family’s later Changed events carry every partition’s deltas together; the consumer demuxes them by the root row’s partition key (the drain does this for the daemon).

Fields

tx_id: TxId

binding: Binding

changes: Vec<ChangeEvent>

Trait Implementations

impl Clone for Update

fn clone(&self) -> Update

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Update

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

Formats the value using the given formatter.