Struct GlobalProjectionCheckpoint 

pub struct GlobalProjectionCheckpoint {
    pub cursors: BTreeMap<StreamId, u64>,
}

Per-stream sequence number cursors for multi-stream projections.

Returned by ProjectionRunner::run_all_streams and ProjectionRunner::catch_up_all_streams. Pass an existing checkpoint to catch_up_all_streams so only events newer than the last replay are fed to the projection.

Persist this value (e.g. alongside the read model in a snapshot store) to survive process restarts and avoid full replays on restart.

A cursor value of 0 for a stream means “never seen” (equivalent to “replay from the beginning”).

Fields

cursors: BTreeMap<StreamId, u64>

Last-processed sequence number per stream identifier.

Streams not present in this map have an implicit cursor of 0.

Implementations

impl GlobalProjectionCheckpoint

pub fn new() -> Self

Create an empty checkpoint (all streams will be fully replayed).

pub fn cursor_for(&self, stream_id: &StreamId) -> u64

The last-processed sequence number for stream_id.

Returns 0 when the stream has never been processed (signals a full replay is needed for that stream).

pub fn advance(&mut self, stream_id: &StreamId, sequence: u64)

Update the cursor for stream_id to sequence (if sequence is greater than the current cursor).

Trait Implementations

impl Clone for GlobalProjectionCheckpoint

fn clone(&self) -> GlobalProjectionCheckpoint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GlobalProjectionCheckpoint

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

Formats the value using the given formatter.

impl Default for GlobalProjectionCheckpoint

fn default() -> GlobalProjectionCheckpoint

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for GlobalProjectionCheckpoint

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for GlobalProjectionCheckpoint

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

where __S: Serializer,

Serialize this value into the given Serde serializer.