What is a Run Id?
A Run Id is a globally unique, platform-level identifier for a Workflow Execution.
Temporal guarantees that only one Workflow Execution with a given Workflow Id can be in an Open state at any given time. But when a Workflow Execution reaches a Closed state, it is possible to have another Workflow Execution in an Open state with the same Workflow Id. For example, a Temporal Cron Job is a chain of Workflow Executions that all have the same Workflow Id. Each Workflow Execution within the chain is considered a Run.
A Run Id uniquely identifies a Workflow Execution even if it shares a Workflow Id with other Workflow Executions.
Don't rely on storing the current Run Id or using it for any logical choices. A Workflow Retry changes the Run Id. Because the current Run Id is mutable, relying on it might produce non-determinism issues.
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