Event stream deletion

[slashdotdash]

Allow an event stream to be soft or hard deleted.

• Soft deletion will make the stream unreadable, but keep the events in the database.

  :ok = EventStore.delete_stream(stream_uuid, :soft)

• Hard delete will remove the stream and its events from the database.

  :ok = EventStore.delete_stream(stream_uuid, :hard)

Events are included in the global $all stream by default. When a stream is deleted the events should also be removed from this stream.

[Freyskeyd]

Hello,

Some questions related to the soft/hard deletion:

• How do we manage event numbers in case of deleted events on $all ?
• What's about linked event when a stream is deleted ?

What I want to do:

Soft deletion

An event shouldn't be removed from the store. When we want to soft delete a stream we just need to add an event to it like a SoftDeletionEvent (or something else).
The stream metadata must be reflect that the last event is the SoftDeletionEvent and must return a :stream_not_found when consuming a stream which have a SoftDeletionEvent has current event.

Creating and adding new event to the stream will revive the stream but only events added after the latest SoftDeletionEvent will be returned.

Question:

• How to handle $all subscription in that case ?
• Should we update the last_seen subscription to the SoftDeletionEvent ?

Hard Deletion

A hard deletion must produce an event reflecting the action (HardDeletionEvent). Any previous events must be deleted.

When requesting a stream which have an HardDeletionEvent a :stream_not_found must be returned.

An HardDeleted stream can be revive and no events can be pushed to it.

Question:

• How to deal with $all subscription in that case ?