I think the author of this test is long gone, but the code originated inside google. This query is not part of the original Nexmark suite but was designed to exercise corner cases caused by out of order events, so that is what you are probably seeing. Here are relevant bits from the original commit messages:
New query 11 to exercise session windows. Q11 started as a basic session windows test with out-of-order and delayed events. This refines the trigger to limit the number of events in sessions. Andrew On Wed, Jun 10, 2020 at 10:37 AM Sruthi S Kumar <[email protected]> wrote: > Hi, > > We are working on a Flink project and enhancing some state backend > functionality. We are using NEXMark benchmark to compare different state > backends performance of Flink. While running NEXMark queries using Flink > runner of Beam we have noticed that there is quite a lot of non-existent > read from the state-backed. > > For example, when running query 11 with RocksDB state-backed, we had > around 368 successful reads while we had around 527 attempts to read > non-existent reads. We are curious if that is intentional and if so what's > the rationale behind it? > > > -- > Regards, > > Sruthi >
