Persistent Flow and DAG Implementation

[ShivamNagpal]

Principles

Persistent Flow

• One Checkpoint can trigger only one action. Only one action can subscribe to a certain checkpoint.
• Multiple Checkpoints can trigger same action. Same action can subscribe to more than one checkpoints.
• Looping back to a previous checkpoint is allowed. This may result in an infinite loop.

DAG

• DAG maintains the dependency of different nodes and allow execution in a co-ordinated way.
• DAG under execution is a persistent flow with the DAG dependency graph as the state.
• DAG itself doesn't execute any node actions. Every node in a DAG translates to another Persistent Flow or DAG.