The changelog is one created by kafka streams, then it is a compacted topic and the retention period is irrelevant. If it is one you have created yourself and isn't compacted, then the data will be retained in the topic for as long as the retention period. If you use a non-compacted topic and the kafka-streams instance crashes then that data may be lost from the state store as it will use the topic to restore its state.
On Wed, 26 Jul 2017 at 10:24 Sameer Kumar <sam.kum.w...@gmail.com> wrote: > ok. Thanks. > > Actually, I had this confusion. Changelog like every Kafka topic would have > its retention period, lets say 2 days. and if the value on day1 for key1 = > 4 and data for key1 doesnt come for next 3 days. Would it still retail the > same value(key1=4) on day4. > > -Sameer. > > On Wed, Jul 26, 2017 at 2:22 PM, Damian Guy <damian....@gmail.com> wrote: > > > Sameer, > > > > For a KeyValue store the changelog topic is a compacted topic so there is > > no retention period. You will always retain the latest value for a key. > > > > Thanks, > > Damian > > > > On Wed, 26 Jul 2017 at 08:36 Sameer Kumar <sam.kum.w...@gmail.com> > wrote: > > > > > Hi, > > > > > > Retention period for state stores are clear(default, otherwise > specified > > by > > > TimeWindows.until). Intrigued to know the retention period for key > > values. > > > > > > The use case is something like I am reading from a windowed store, and > > > using plain reduce() with out any time windows. Would the values be > > > retained foreever. > > > > > > -Sameer. > > > > > >
