Suppose I specify UnloadOnIdle to true and LoadIntervalSeconds to 1 hr when creating the SqlWorkflowPersistenceService.

Consequently, I believe my workflow will be persisted to the db for 1 hr when it hits an HandleExternalEvent activity.

Since SqlWorkflowPersistenceService will not re-load the workflow again in 1 hr, what happens to the events sent to the workflow instance during this time?

Are the events stored in a queue somewhere? Does the workflow runtime store them? Are the stored events sent to the workflow instance one at a time when the instance is rehydrated?

Thanks in advance.

LoadIntervalSeconds does not indicate how long an instance should be left unloaded. LoadIntervalSeconds does not affect message delivery. If you send a message to an instance the instance will be immediately (synchronously) loaded from the persistence store in order to receive the message.

LoadIntervalSeconds is used to specify how often the SqlWorkflowPersistenceService checks the database for unloaded instances with expired timers. If you have an instance that goes idle because it is waiting on a 5 minute timer and the instance is unloaded it will not be reloaded for up to 1 hour and 5 minutes (depending on how long it has been since the last.time the database was checked). Typically you want to set this value to be anywhere from seconds to minutes depending on how much accuracy you need from your durable timers.

Thanks,
Joel West
MSFTE - SDE in WF runtime and hosting

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