Hi, Rex Fenley ~ If there is stateful operator as the output of the aggregate function. Then each time the function receives an update (or delete) for the key, the agg operator would emit 2 messages, one for retracting the old record, one for the new message. For your case, the new message is the DELETE.
If there is no stateful operator, the aggregate operator would just emit the update after (the new) message which is the delete. Rex Fenley <r...@remind101.com> 于2020年12月9日周三 上午4:30写道： > Hello, > > I'd like to better understand delete behavior of AggregateFunctions. Let's > assume there's an aggregate of `user_id` to a set of `group_ids` for groups > belonging to that user. > `user_id_1 -> [group_id_1, group_id_2, etc.]` > Now let's assume sometime later that deletes arrive for all rows which > produce user_id_1's group_id's. > > Would the aggregate function completely delete the associated state from > RocksDB or would it leave something like `user_id_1 -> []` sitting in > RocksDB forever? > > We have an aggregate similar to this where users could delete themselves > and we want to make sure we're not accumulating data forever for those > users. > > Thanks! > > -- > > Rex Fenley | Software Engineer - Mobile and Backend > > > Remind.com <https://www.remind.com/> | BLOG <http://blog.remind.com/> | > FOLLOW US <https://twitter.com/remindhq> | LIKE US > <https://www.facebook.com/remindhq> >
