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 <[EMAIL PROTECTED]> wrote: