What does it meant to be a persistent callback?

Question

When hearing phrases such as triggering a persistent callback, what does it mean to be persistent?

Edit: Needed more context. This was the paragraph I was trying to parse:

Actor reminders Reminders are a mechanism to trigger persistent callbacks on an actor at specified times. Their functionality is similar to timers. But unlike timers, reminders are triggered under all circumstances until the actor explicitly unregisters them or the actor is explicitly deleted. Specifically, reminders are triggered across actor deactivations and failovers because the Actors runtime persists information about the actor's reminders.

Source: https://azure.microsoft.com/en-us/documentation/articles/service-fabric-reliable-actors-timers-reminders/

Persistent means it keeps happening or keeps getting triggered. — Blue Eyed Behemoth
So when someone says that a runtime persists information, does that mean the information in the runtime keeps getting triggered as well? — halois
googling persistent callback doesn't turn up anything obvious, and I've never encountered the term otherwise. To me, it doesn't make much sense without some context. — Jonesopolis
I don't think that "persistent callback" is something well defined in programming. It's just a way of saying. Persistence for example in layerd architecture is that part which has the responsability of saving objects. But I don't think it has the same meaning here. — meJustAndrew
@halois No, in that context it just means a runtime holds the information, like it doesn't go away. — Blue Eyed Behemoth

meJustAndrew meJustAndrew · Accepted Answer · 2016-06-30T18:38:13

As I said in the comment, persistence refers to thatnpart in a program specialized in saving or updating the stored data. Such as in layerd architecture the "Repository" which can be a database or just some files.

In your question it is specified that the persistent callback is made on an actor, that is unregistered, or the actor that is deleted. So you can see, this changes made to the data, in this case the actor which is deleted, and this behavior is marked by the word persistence. It just means that it "persist" some data.

To clarify this, persistent callback is just a callback responsable to sotre or delete some data.

What does it meant to be a persistent callback?

1 Answers