Yeah, if users are using Kryo directly, they should be insulated from a Spark-side change because of shading. However this also entails updating (unshaded) Chill from 0.8.x to 0.9.x. I am not sure if that causes problems for apps.
Normally I'd avoid any major-version change in a minor release. This one looked potentially entirely internal. I think if there are any doubts, we can leave it for Spark 3. There was a bug report that needed a fix from Kryo 4, but it might be minor after all. On Fri, Jan 19, 2018 at 11:05 AM Koert Kuipers <ko...@tresata.com> wrote: > it is mainly a problem because for reasons of sanity one wants to keep > single kryo/chill version, and kryo/chill could be used in other places for > somewhat persistent serialization by the user. > > i know, this is not spark's problem... it is the users problem. but i > would find it odd to change kryo in a minor upgrade in general. not that it > cannot be done. > > > > On Fri, Jan 19, 2018 at 8:55 AM, Sean Owen <so...@cloudera.com> wrote: > >> See: >> >> https://issues.apache.org/jira/browse/SPARK-23131 >> https://github.com/apache/spark/pull/20301#issuecomment-358473199 >> >> I expected a major Kryo upgrade to be problematic, but it worked fine. It >> picks up a number of fixes: >> https://github.com/EsotericSoftware/kryo/releases/tag/kryo-parent-4.0.0 >> >> It might be good for Spark 2.4. >> >> Its serialized format isn't entirely compatible though. I'm trying to >> recall whether this is a problem in practice. We don't guarantee wire >> compatibility across mismatched Spark versions, right? >> >> But does the Kryo serialized form show up in any persistent stored form? >> I don't believe any normal output, even that of saveAsObjectFile, uses it. >> >> I'm wondering if I am not recalling why this would be a problem to update? >> >> Sean >> > >
