Enum int_compute::Event

pub enum Event {
    FlowStarted(FlowTags),
    FlowTerminated(FlowTags),
    FlowUpdated {
        flow: FlowTags,
        columns: HashSet<Ident>,
    },
    CorkRequest(Cork),
}

Some event the internal computation might want to react to.

All the variants that are caused by a concrete flow carry the FlowTags handle. It can be both used to examine the flow (it contains the current headers of the flow) and to reference the flow in a newly created update.

Variants

FlowStarted(FlowTags)

A flow has started.

FlowTerminated(FlowTags)

A flow has been dropped.

This isn't the same as the flow being closed. This is triggered when the flow is destroyed in the in-memory representation. Therefore, generating new updates for this flow is useless (there will be no flow to apply them to) and the purpose is mainly to trigger clearing of computations' internal caches.

FlowUpdated

Something changed on a flow.

Fields of FlowUpdated

flow: FlowTags	Handle to the changed flow.
columns: HashSet<Ident>	Identities of the columns that changed. This contains both the newly added columns and columns with updated values. Note that the value might have been replaced by the same value.

CorkRequest(Cork)

There's a request to cork (flush) previous updates.

If the computation produced any updates since the last CorkRequest, a clone of the provided Cork must be pushed through the sender channel. This ensures all the updates are applied before the corresponding time slice is closed.

It is recommended to simply push the clone into the stream every time the event comes, without keeping track if any updates happened.

Trait Implementations

impl Debug for Event

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.