Enum CheckpointPolicy 

pub enum CheckpointPolicy {
    PersistAfterAdvance,
    AdvanceOnly,
    IntervalWhenDrained {
        interval: Duration,
    },
}

When to call SourceDriver::persist_checkpoint.

Persistence is always sink-safe only: the runtime never asks a driver to persist a position past unsunk transform/apply work. Drivers that map the persist argument to a read-ahead cursor must only do so when the apply window is drained (see IntervalWhenDrained).

Variants

PersistAfterAdvance

After each successful sink + advance_watermark, also call SourceDriver::persist_checkpoint with that position.

AdvanceOnly

Do not call persist_checkpoint (driver folds durability into advance_watermark).

IntervalWhenDrained

Persist sink-safe positions when the apply window is fully drained (no buffer / in-flight / completed-waiting):

• After an advance_watermark, if the window is already drained, persist that sink-safe watermark promptly (same durability cadence as persisting last-sunk on sink success).
• Otherwise arm a pending watermark and flush once the window drains and at least interval has elapsed since the last persist.
• When drained with no pending advance (filtered-only / idle read progress), call SourceDriver::read_progress_for_persist on the same interval so drivers can advance a store cursor through noise without reintroducing unsunk read-ahead.

interval = Duration::ZERO persists whenever the window is drained (still never advances past unsunk work). On stop flush, any pending sink-safe position is force-persisted.

Fields

interval: Duration

Minimum time between deferred / filtered-only persist_checkpoint calls.

Trait Implementations

impl Clone for CheckpointPolicy

fn clone(&self) -> CheckpointPolicy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CheckpointPolicy

impl Debug for CheckpointPolicy

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

Formats the value using the given formatter.

impl Default for CheckpointPolicy

fn default() -> CheckpointPolicy

Returns the “default value” for a type.

impl Eq for CheckpointPolicy

impl PartialEq for CheckpointPolicy

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for CheckpointPolicy