Is the intention to bump the Flink major version and only support Java 17+? If so, can Scala not be upgraded at the same time?
Thanks, Thomas On Thu, Apr 27, 2023 at 4:53 PM Martijn Visser <martijnvis...@apache.org> wrote: > Scala 2.12.7 doesn't compile on Java 17, see > https://issues.apache.org/jira/browse/FLINK-25000. > > On Thu, Apr 27, 2023 at 3:11 PM Jing Ge <j...@ververica.com> wrote: > > > Thanks Tamir for the information. According to the latest comment of the > > task FLINK-24998, this bug should be gone while using the latest JDK 17. > I > > was wondering whether it means that there are no more issues to stop us > > releasing a major Flink version to support Java 17? Did I miss something? > > > > Best regards, > > Jing > > > > On Thu, Apr 27, 2023 at 8:18 AM Tamir Sagi <tamir.s...@niceactimize.com> > > wrote: > > > >> More details about the JDK bug here > >> https://bugs.openjdk.org/browse/JDK-8277529 > >> > >> Related Jira ticket > >> https://issues.apache.org/jira/browse/FLINK-24998 > >> > >> ------------------------------ > >> *From:* Jing Ge via user <user@flink.apache.org> > >> *Sent:* Monday, April 24, 2023 11:15 PM > >> *To:* Chesnay Schepler <ches...@apache.org> > >> *Cc:* Piotr Nowojski <pnowoj...@apache.org>; Alexis Sarda-Espinosa < > >> sarda.espin...@gmail.com>; Martijn Visser <martijnvis...@apache.org>; > >> d...@flink.apache.org <d...@flink.apache.org>; user < > user@flink.apache.org> > >> *Subject:* Re: [Discussion] - Release major Flink version to support JDK > >> 17 (LTS) > >> > >> > >> *EXTERNAL EMAIL* > >> > >> > >> Thanks Chesnay for working on this. Would you like to share more info > >> about the JDK bug? > >> > >> Best regards, > >> Jing > >> > >> On Mon, Apr 24, 2023 at 11:39 AM Chesnay Schepler <ches...@apache.org> > >> wrote: > >> > >> As it turns out Kryo isn't a blocker; we ran into a JDK bug. > >> > >> On 31/03/2023 08:57, Chesnay Schepler wrote: > >> > >> > >> > https://github.com/EsotericSoftware/kryo/wiki/Migration-to-v5#migration-guide > >> > >> Kroy themselves state that v5 likely can't read v2 data. > >> > >> However, both versions can be on the classpath without classpath as v5 > >> offers a versioned artifact that includes the version in the package. > >> > >> It probably wouldn't be difficult to migrate a savepoint to Kryo v5, > >> purely from a read/write perspective. > >> > >> The bigger question is how we expose this new Kryo version in the API. > If > >> we stick to the versioned jar we need to either duplicate all current > >> Kryo-related APIs or find a better way to integrate other serialization > >> stacks. > >> On 30/03/2023 17:50, Piotr Nowojski wrote: > >> > >> Hey, > >> > >> > 1. The Flink community agrees that we upgrade Kryo to a later version, > >> which means breaking all checkpoint/savepoint compatibility and > releasing a > >> Flink 2.0 with Java 17 support added and Java 8 and Flink Scala API > support > >> dropped. This is probably the quickest way, but would still mean that we > >> expose Kryo in the Flink APIs, which is the main reason why we haven't > been > >> able to upgrade Kryo at all. > >> > >> This sounds pretty bad to me. > >> > >> Has anyone looked into what it would take to provide a smooth migration > >> from Kryo2 -> Kryo5? > >> > >> Best, > >> Piotrek > >> > >> czw., 30 mar 2023 o 16:54 Alexis Sarda-Espinosa < > sarda.espin...@gmail.com> > >> napisał(a): > >> > >> Hi Martijn, > >> > >> just to be sure, if all state-related classes use a POJO serializer, > Kryo > >> will never come into play, right? Given FLINK-16686 [1], I wonder how > many > >> users actually have jobs with Kryo and RocksDB, but even if there aren't > >> many, that still leaves those who don't use RocksDB for > >> checkpoints/savepoints. > >> > >> If Kryo were to stay in the Flink APIs in v1.X, is it impossible to let > >> users choose between v2/v5 jars by separating them like log4j2 jars? > >> > >> [1] https://issues.apache.org/jira/browse/FLINK-16686 > >> > >> Regards, > >> Alexis. > >> > >> Am Do., 30. März 2023 um 14:26 Uhr schrieb Martijn Visser < > >> martijnvis...@apache.org>: > >> > >> Hi all, > >> > >> I also saw a thread on this topic from Clayton Wohl [1] on this topic, > >> which I'm including in this discussion thread to avoid that it gets > lost. > >> > >> From my perspective, there's two main ways to get to Java 17: > >> > >> 1. The Flink community agrees that we upgrade Kryo to a later version, > >> which means breaking all checkpoint/savepoint compatibility and > releasing a > >> Flink 2.0 with Java 17 support added and Java 8 and Flink Scala API > support > >> dropped. This is probably the quickest way, but would still mean that we > >> expose Kryo in the Flink APIs, which is the main reason why we haven't > been > >> able to upgrade Kryo at all. > >> 2. There's a contributor who makes a contribution that bumps Kryo, but > >> either a) automagically reads in all old checkpoints/savepoints in using > >> Kryo v2 and writes them to new snapshots using Kryo v5 (like is > mentioned > >> in the Kryo migration guide [2][3] or b) provides an offline tool that > >> allows users that are interested in migrating their snapshots manually > >> before starting from a newer version. That potentially could prevent the > >> need to introduce a new Flink major version. In both scenarios, ideally > the > >> contributor would also help with avoiding the exposure of Kryo so that > we > >> will be in a better shape in the future. > >> > >> It would be good to get the opinion of the community for either of these > >> two options, or potentially for another one that I haven't mentioned. > If it > >> appears that there's an overall agreement on the direction, I would > propose > >> that a FLIP gets created which describes the entire process. > >> > >> Looking forward to the thoughts of others, including the Users > (therefore > >> including the User ML). > >> > >> Best regards, > >> > >> Martijn > >> > >> [1] https://lists.apache.org/thread/qcw8wy9dv8szxx9bh49nz7jnth22p1v2 > >> [2] https://lists.apache.org/thread/gv49jfkhmbshxdvzzozh017ntkst3sgq > >> [3] https://github.com/EsotericSoftware/kryo/wiki/Migration-to-v5 > >> > >> On Sun, Mar 19, 2023 at 8:16 AM Tamir Sagi <tamir.s...@niceactimize.com > > > >> wrote: > >> > >> I agree, there are several options to mitigate the migration from v2 to > >> v5. > >> yet, Oracle roadmap is to end JDK 11 support in September this year. > >> > >> > >> > >> ________________________________ > >> From: ConradJam <jam.gz...@gmail.com> > >> Sent: Thursday, March 16, 2023 4:36 AM > >> To: d...@flink.apache.org <d...@flink.apache.org> > >> Subject: Re: [Discussion] - Release major Flink version to support JDK > 17 > >> (LTS) > >> > >> EXTERNAL EMAIL > >> > >> > >> > >> Thanks for your start this discuss > >> > >> > >> I have been tracking this problem for a long time, until I saw a > >> conversation in ISSUSE a few days ago and learned that the Kryo version > >> problem will affect the JDK17 compilation of snapshots [1] FLINK-24998 , > >> > >> As @cherry said it ruined our whole effort towards JDK17 > >> > >> I am in favor of providing an external tool to migrate from Kryo old > >> version checkpoint to the new Kryo new checkpoint at one time (Maybe > this > >> tool start in flink 2.0 ?), does this tool currently have any plans or > >> ideas worth discuss > >> > >> > >> I think it should not be difficult to be compatible with JDK11 and > JDK17. > >> We should indeed abandon JDK8 in 2.0.0. It is also mentioned in the doc > >> that it is marked as Deprecated [2] > >> > >> > >> Here I add that we need to pay attention to the version of Scala and the > >> version of JDK17 > >> > >> > >> [1] FLINK-24998 IGSEGV in Kryo / C2 CompilerThread on Java 17 > >> https://issues.apache.org/jira/browse/FLINK-24998 > >> > >> [2] FLINK-30501 Update Flink build instruction to deprecate Java 8 > instead > >> of requiring Java 11 https://issues.apache.org/jira/browse/FLINK-30501 > >> > >> Tamir Sagi <tamir.s...@niceactimize.com> 于2023年3月16日周四 00:54写道： > >> > >> > Hey dev community, > >> > > >> > I'm writing this email to kick off a discussion following this epic: > >> > FLINK-15736<https://issues.apache.org/jira/browse/FLINK-15736>. > >> > > >> > We are moving towards JDK 17 (LTS) , the only blocker now is Flink > which > >> > currently remains on JDK 11 (LTS). Flink does not support JDK 17 yet, > >> with > >> > no timeline, the reason, based on the aforementioned ticket is the > >> > following tickets > >> > > >> > 1. FLINK-24998 - SIGSEGV in Kryo / C2 CompilerThread on Java 17< > >> > https://issues.apache.org/jira/browse/FLINK-24998>. > >> > 2. FLINK-3154 - Update Kryo version from 2.24.0 to latest Kryo LTS > >> > version<https://issues.apache.org/jira/browse/FLINK-3154> > >> > > >> > My question is whether it is possible to release a major version > (Flink > >> > 2.0.0) using the latest Kryo version for those who don't need to > restore > >> > old savepoints/checkpoints in newer format. > >> > > >> > 1. Leverage JDK 17 features within JVM > >> > 2. Moving from the old format to the newer one will be handled only > >> > once - a mitigation can be achieved by a conversion tool or external > >> > serializers, both can be provided later on. > >> > > >> > I'd like to emphasize that the next JDK LTS (21) will be released this > >> > September. furthermore, Flink already supports JDK 12-15, which is > very > >> > close to JDK 17 (LTS) - that was released in September 2021. JDK 11 > >> will > >> > become a legacy soon, as more frameworks moving towards JDK 17 and are > >> less > >> > likely to support JDK 11 in the near future. (For example, Spring > Boot 3 > >> > requires JDK 17 already). > >> > > >> > Thank you for your consideration of my request. > >> > > >> > Tamir. > >> > > >> > > >> > > >> > > >> > Confidentiality: This communication and any attachments are intended > for > >> > the above-named persons only and may be confidential and/or legally > >> > privileged. Any opinions expressed in this communication are not > >> > necessarily those of NICE Actimize. If this communication has come to > >> you > >> > in error you must take no action based on it, nor must you copy or > show > >> it > >> > to anyone; please delete/destroy and inform the sender by e-mail > >> > immediately. > >> > Monitoring: NICE Actimize may monitor incoming and outgoing e-mails. > >> > Viruses: Although we have taken steps toward ensuring that this e-mail > >> and > >> > attachments are free from any virus, we advise that in keeping with > good > >> > computing practice the recipient should ensure they are actually virus > >> free. > >> > > >> > >> > >> -- > >> Best > >> > >> ConradJam > >> > >> Confidentiality: This communication and any attachments are intended for > >> the above-named persons only and may be confidential and/or legally > >> privileged. Any opinions expressed in this communication are not > >> necessarily those of NICE Actimize. If this communication has come to > you > >> in error you must take no action based on it, nor must you copy or show > it > >> to anyone; please delete/destroy and inform the sender by e-mail > >> immediately. > >> Monitoring: NICE Actimize may monitor incoming and outgoing e-mails. > >> Viruses: Although we have taken steps toward ensuring that this e-mail > >> and attachments are free from any virus, we advise that in keeping with > >> good computing practice the recipient should ensure they are actually > virus > >> free. > >> > >> > >> > >> > >> Confidentiality: This communication and any attachments are intended for > >> the above-named persons only and may be confidential and/or legally > >> privileged. Any opinions expressed in this communication are not > >> necessarily those of NICE Actimize. If this communication has come to > you > >> in error you must take no action based on it, nor must you copy or show > it > >> to anyone; please delete/destroy and inform the sender by e-mail > >> immediately. > >> Monitoring: NICE Actimize may monitor incoming and outgoing e-mails. > >> Viruses: Although we have taken steps toward ensuring that this e-mail > >> and attachments are free from any virus, we advise that in keeping with > >> good computing practice the recipient should ensure they are actually > virus > >> free. > >> > > >
