[ https://issues.apache.org/jira/browse/KAFKA-4726?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Matthias J. Sax reassigned KAFKA-4726: -------------------------------------- Assignee: Jeyhun Karimov > ValueMapper should have (read) access to key > -------------------------------------------- > > Key: KAFKA-4726 > URL: https://issues.apache.org/jira/browse/KAFKA-4726 > Project: Kafka > Issue Type: Improvement > Components: streams > Affects Versions: 0.10.1.1 > Reporter: Steven Schlansker > Assignee: Jeyhun Karimov > Labels: kip > > {{ValueMapper}} should have read-only access to the key for the value it is > mapping. Sometimes the value transformation will depend on the key. > It is possible to do this with a full blown {{KeyValueMapper}} but that loses > the promise that you won't change the key -- so you might introduce a > re-keying phase that is totally unnecessary. It also requires you to return > an identity KeyValue object which costs something to construct (unless we are > lucky and the optimizer elides it). > [ If mapValues() is guaranteed to be no less efficient than map() the issue > may be moot, but I presume there are some optimizations that are valid with > the former but not latter. ] -- This message was sent by Atlassian JIRA (v6.4.14#64029)