使用`now（）`重新思考DB changefeed过滤

Question

I was hoping to create a sort of 'time tigger' using RethinkDB changefeeds:

        return r.
            Table("Checks").
            Filter(r.Row.Field("ScheduledFor").Le(r.Now())).
            Changes(r.ChangesOpts{
                    IncludeInitial: true,
            }).Run(db)

However, while it picks up things that initially fulfill the Filter predicate, it does not appear to pick up records where ScheduledFor goes from being in the future to being in the past.

i.e. r.Now() appears to be evaluated upon being received by the server and never again.

Is there any way to make the Now() term dynamically evaluated? Or should I just do a table scan?

Answer 1

Currently r.now always evaluates to the time the server received the query. It's probably best to repeatedly do a table scan for any documents scheduled between the last table scan and the current time.