Hi John, I’ve not dug into this yet, but IMO, it shouldn’t be the case. I just wonder how do you judge that the data in the first five seconds are not processed by the system?
Best, Xingcan > On Sep 17, 2018, at 11:21 PM, John Stone <elliotst...@gmail.com> wrote: > > Hello, > > I'm checking if this is intentional or a bug in Apache Flink SQL (Flink > 1.6.0). > > I am using processing time with a RocksDB backend. I have not checked if > this issue is also occurring in the Table API. I have not checked if this > issue also exists for event time (although I suspect it does). > > Consider the following two queries: > > "SELECT foo, COUNT(bar) > FROM MyTable > WHERE faz = 'xyz' > GROUP BY HOP(myTime, INTERVAL '1' SECOND, INTERVAL '5' SECOND), foo" > > and > > "SELECT foo, COUNT(bar) > FROM MyTable > WHERE faz = 'xyz' > GROUP BY TUMBLE(myTime, INTERVAL '5' SECOND), foo" > > I have found in my testing for both of the above that events received in the > first 5 seconds are ignored. In other words, the first window interval is > effectively a black hole, and only events which are received starting after > the first 5 seconds of the stream being "up" are processed. > > Is this ignoring of events during the first interval a bug or intentional? > > Many thanks, > > John
