[Discuss][Search Sessions] Synchronizing async_search keepslive updates

[lizozom]

In order to avoid having "abandoned" searches that keep running, after a user has closed Kibana, In #73712, we started extending the keep_alive of async_search requests by 1m every time we poll them.

However, with the release of Search Sessions coming upon us, this workaround creates a problem. When a Search Session is being stored, we need to extend the expiration of the searches it contains, creating a potential race condition. When the race condition happens, we would save a Search Session and then some of the searches in it will expire, and show errors when restoring.

@jimczi and I have discussed a couple of solutions:

• Allowing the expiration to have a script in it, that will apply the keepalive update only if the current expiration time is near
• Supporting separate parameters for the actual keep alive and for the polling behavior.

And now the Elasticsearch need to decide how they prefer to work around this problem.

[dnhatn]

I've merged elastic/elasticsearch#67877 that will always extend the keep_alive; hence, it never goes backward. I think we are good here.

[lizozom]

Resolved by #89570