Workflow Execution: The Execution Store
The Execution Store is a data structure owned and maintained inside each
WorkflowExecutionActor (see Major Actors).
Its purpose is to hold the current status of what the workflow is doing, what it has done, and what it has left to do. If the WOM graph holds a static representation of the workflow which doesn't change as the workflow is run, the Execution Store holds the dynamic status of each node in the graph at any given moment in time.
The Execution Store is also used to answer questions like "which nodes in the workflow graph are ready to run because their dependencies are satisfied?".
Note: The Execution Store does not hold the values which are generated by running the various nodes in the WOM graph. That is the domain of the Value Store.
The Execution Store is a mapping from WOM nodes (and a shard index, if necessary) to the execution status of those nodes in the actual workflow.
Some worked through examples of how the Execution Store and Value Store change as workflows progress are given on the Execution and Value Store Examples page.