Best practices for unlinking from stream

[Bertg]

We have been using the event store to keep track of events regarding a tree like structure. This has been working great, but we have started noticing some very weird performance issues.

In our code we noticed that we were doing something like this (pseudo-code)

publish_event(event, stream: "THING-#{event.thing_id}"
link_event(event, stream: "THING-#{event.thing_parent_id}"

Our projection logic handles these case properly (lots of IFs), but you can imagine that we select WAY more events to project a folder than needed.
It is not clear anymore why this was done (maybe we thought this would be useful down the line? or we didn't understand event sourcing exactly)... doesn't matter.

We now want to unlink these events (pseudo code)

get_streams_with_issues.each do |stream_name|
  events_in_stream(stream_name).each do |event|
    unlink_event(event, stream_name) unless "THING-#{event.thing_id}" == stream_name
  end
end

At this time we can not find a way to unlink these events in the docs. Should we just do a direct delete in the database? Any caveats we need to worry about?

[mostlyobvious]

You're right about missing unlink in the API. Direct manipulation or adding project-specific functionality to the event store client adapter are the best options now.

Regarding possible drawbacks — I've summarized my concerns here.

I think it is safer to rewrite the stream, omitting particular events. This way you'll always get continuous positions.