Hi everybody, Thanks a lot for your detailed feedback on this topic. It looks like we can already do some preliminary wrap-up for this discussion.
As far as I see we have the following trends: *Last access timestamp: **Event timestamp of currently being processed record* *Current timestamp to check expiration, *two options: - *Last emitted watermark* *- **Current processing time* >From the implementation perspective, it does not seem to be a big deal to make it configurable as we already have processing time provider. Although, it looks like our TtlTimeProvider would need two methods from now on: getAccessTimestamp and getCurrentTimestamp. The biggest concern is out-of-orderness problem. In general, from Flink side it does not look that we can do a lot about it except putting again a caveat into the user docs about it. It depends on the use case whether the out-of-orderness can be tolerated or not and whether an additional stream ordering operator needs to be put before TTL state access. I would still consider TTL event time feature to be implemented as we have some user requests for it. Any further feedback is appreciated. Best, Andrey On Tue, Apr 9, 2019 at 5:26 PM aitozi <gjying1...@gmail.com> wrote: > Hi, Andrey > > I think ttl state has another scenario to simulate the slide window with > the > process function. User can define a state to store the data with the latest > 1 day. And trigger calculate on the state every 5min. It is a operator > similar to slidewindow. But i think it is more efficient than the > slidewindow because it dont have to store the redundant data and the expire > data can be delete automatic. > > However with the support of ttl state based on processing time we can just > implement the processing slide window. If we can support ttl based on event > time I think we can expand this capacity. > > So in this scenario, the event-time-accesstime/watermark-expiration-check > will be the proper combination. > > I think if can add the interface to allow user to custom will be flexible. > > Thanks, > Aitozi > > > > -- > Sent from: > http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/ >
