Thanks for bringing this up. I'm +1 on enabling the incremental checkpoint by default on RocksDB. But I also agree with Yuan about not enabling this on newly implemented incremental checkpoint for hashmap statebackend. I am wondering can we make it behave differently for different state backends when ```state.backend.incremental``` is not set? Although it may bring some confusion in the default behaviour.
On Thu, Jun 16, 2022 at 10:18 PM Lihe Ma <ma_l...@163.com> wrote: > Thanks for the suggestion, Yuan. > > > How about naming the newly in-memory state-backend, which supports > incremental checkpoint, as HeapStateBackend . And let the default > state-backend still stay as HashMapStateBackend. > By doing so, we can: > 1) the default value of parameter state.backend.incremental could be set > as true safely, which is so widely accepted according to the replies in > this thread. > 2) your newly in-memory state-backend could also be merged and users who > want to try in-memory incremental checkpoints could also have a solution. > We can also set the newly HeapStateBackend as default state-backend in the > future if the feature of incremental checkpoint is stable. What do you > think? > > > Best, > Lihe Ma > > > > > > > > > > > > > > > > 在 2022-06-15 21:03:31，"Feifan Wang" <zoltar9...@163.com> 写道： > >Thanks for bringing this up. > >Strongly +1 > > > > > > > > > >—————————————— > >Name: Feifan Wang > >Email: zoltar9...@163.com > > > > > >---- Replied Message ---- > >| From | Yuan Mei<yuanmei.w...@gmail.com> | > >| Date | 06/15/2022 11:41 | > >| To | dev<dev@flink.apache.org> , > ><ro...@ververica.com> | > >| Subject | Re: [DISCUSS ] Make state.backend.incremental as true by > default | > >Thanks for bringing this up. > > > >I am +1 on making incremental checkpoints by default for RocksDB, but not > >universally for all state backends. > > > >Besides being widely used in prod, enabling incremental checkpoint for > >RocksDB by default is also a pre-requisite when enabling task-local by > >default FLINK-15507 <https://issues.apache.org/jira/browse/FLINK-15507> > > > >The incremental checkpoint for the hashmap statebackend is under review > >right now. CC @ro...@ververica.com <ro...@ververica.com> , which is not a > >good idea being enabled by default in the first version. > > > >Best, > > > >Yuan > > > >On Tue, Jun 14, 2022 at 7:33 PM Jiangang Liu <liujiangangp...@gmail.com> > >wrote: > > > >+1 for the suggestion. We have use the incremental checkpoint in our > >production for a long time. > > > >Hangxiang Yu <master...@gmail.com> 于2022年6月14日周二 15:41写道： > > > >+1 > >It's basically enabled in most scenarios in production environments. > >For HashMapStateBackend, it will adopt a full checkpoint even if we > >enable > >incremental checkpoint. It will also support incremental checkpoint after > >[1]. It's compatible. > >BTW, I think we may also need to improve the documentation of incremental > >checkpoints which users usually ask. There are some tickets like [2][3]. > > > >Best, > >Hangxiang. > > > >[1] https://issues.apache.org/jira/browse/FLINK-21648 > >[2] https://issues.apache.org/jira/browse/FLINK-22797 > >[3] https://issues.apache.org/jira/browse/FLINK-7449 > > > >On Mon, Jun 13, 2022 at 7:48 PM Rui Fan <1996fan...@gmail.com> wrote: > > > >Strongly +1 > > > >Best, > >Rui Fan > > > >On Mon, Jun 13, 2022 at 7:35 PM Martijn Visser < > >martijnvis...@apache.org > > > >wrote: > > > >BTW, from my knowledge, nothing would happen for > >HashMapStateBackend, > >which does not support incremental checkpoint yet, when enabling > >incremental checkpoints. > > > >Thanks Yun, if no errors would occur then definitely +1 to enable it > >by > >default > > > >Op ma 13 jun. 2022 om 12:42 schreef Alexander Fedulov < > >alexan...@ververica.com>: > > > >+1 > > > >From my experience, it is actually hard to come up with use cases > >where > >incremental checkpoints should explicitly not be enabled with the > >RocksDB > >state backend. If the state is so small that the full snapshots do > >not > >have any negative impact, one should consider using > >HashMapStateBackend > >anyway. > > > >Best, > >Alexander Fedulov > > > > > >On Mon, Jun 13, 2022 at 12:26 PM Jing Ge <j...@ververica.com> > >wrote: > > > >+1 > > > >Glad to see the kickoff of this discussion. Thanks Lihe for > >driving > >this! > > > >We have actually already discussed it internally a few months > >ago. > >After > >considering some corner cases, all agreed on enabling the > >incremental > >checkpoint as default. > > > >Best regards, > >Jing > > > >On Mon, Jun 13, 2022 at 12:17 PM Yun Tang <myas...@live.com> > >wrote: > > > >Strongly +1 for making incremental checkpoints as default. Many > >users > >have > >ever been asking why this configuration is not enabled by > >default. > > > >BTW, from my knowledge, nothing would happen for > >HashMapStateBackend, > >which does not support incremental checkpoint yet, when > >enabling > >incremental checkpoints. > > > > > >Best > >Yun Tang > >________________________________ > >From: Martijn Visser <martijnvis...@apache.org> > >Sent: Monday, June 13, 2022 18:05 > >To: dev@flink.apache.org <dev@flink.apache.org> > >Subject: Re: [DISCUSS ] Make state.backend.incremental as true > >by > >default > > > >Hi Lihe, > > > >What happens if we enable incremental checkpoints by default > >while > >the > >used > >memory backend is HashMapStateBackend, which doesn't support > >incremental > >checkpoints? > > > >Best regards, > > > >Martijn > > > >Op ma 13 jun. 2022 om 11:59 schreef Lihe Ma <ma_l...@163.com>: > > > >Hi, Everyone, > > > >I would like to open a discussion on setting incremental > >checkpoint > >as > >default behavior. > > > >Currently, the configuration of state.backend.incremental is > >set > >as > >false > >by default. Incremental checkpoint has been adopted widely in > >industry > >community for many years , and it is also well-tested from > >the > >feedback > >in > >the community discussion. Incremental checkpointing is more > >light-weighted: > >shorter checkpoint duration, less uploaded data and less > >resource > >consumption. > > > >In terms of backward compatibility, enable incremental > >checkpointing > >would > >not make any data loss no matter restoring from a full > >checkpoint/savepoint > >or an incremental checkpoint. > > > >FLIP-193 (Snapshot ownership)[1] has been released in 1.15, > >incremental > >checkpoint no longer depends on a previous restored > >checkpoint > >in > >default > >NO_CLAIM mode, which makes the checkpoint lineage much > >cleaner, > >it > >is a > >good chance to change the configuration > >state.backend.incremental > >to > >true > >as default. > > > >Thus, based on the above discussion, I suggest to make > >state.backend.incremental as true by default. What do you > >think > >of > >this > >proposal? > > > >[1] > > > > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-193%3A+Snapshots+ownership > > > >Best regards, > >Lihe Ma > > > > > > > > > > > > > > > > >
