Hi everyone, I started a vote for this FLIP [1], please vote there or ask additional questions here. [2]
[1] https://lists.apache.org/thread/bb0kqjs8co3hhmtklmwptws4fc4rz810 [2] https://lists.apache.org/thread/9k1sl2519kh2n3yttwqc00p07xdfns3h Best, Lincoln Lee Lincoln Lee <lincoln.8...@gmail.com> 于2022年6月2日周四 15:51写道： > Hi everyone, > > When reviewing the name of the hint option 'miss-retry'='true|false', I > feel the current name is not precise enough, it might be easier to > understand by using the retry-predicate directly from flip-232, > e.g. 'retry-predicate'='lookup-miss', which has the additional benefit of > extensibility(maybe more retry condition in the future). > > Jark & Jingsong, do you have any suggestions? If we agree with the name > 'retry-predicate' or other better candidate, I'll update the FLIP. > > Best, > Lincoln Lee > > > Lincoln Lee <lincoln.8...@gmail.com> 于2022年6月2日周四 11:23写道： > >> Hi everyone, >> >> I've updated the FLIP[1] based on this discussion thread that we agree to >> have a single unified 'LOOKUP' hint and also a related part in FLIP-221[2] >> which is mainly for the necessity of the common table option >> 'lookup.async'. >> >> The main updates are: >> 1. the new unified 'LOOKUP' hint, make retry support both on sync and >> async lookup >> 2. clarify the default choice of the planner for those connectors which >> have both sync and async lookup capabilities, and how to deal with the >> query hint >> 3. will add a followup issue to discuss whether to remove the >> 'lookup.async' option in HBase connector. >> >> [1] >> https://cwiki.apache.org/confluence/display/FLINK/FLIP-234%3A+Support+Retryable+Lookup+Join+To+Solve+Delayed+Updates+Issue+In+External+Systems >> [2] https://lists.apache.org/thread/1vokqdnnt01yycl7y1p74g556cc8yvtq >> >> Best, >> Lincoln Lee >> >> >> Lincoln Lee <lincoln.8...@gmail.com> 于2022年6月1日周三 16:03写道： >> >>> Hi Jingsong, >>> >>> There will be no change for connectors with only one capability (sync or >>> async). >>> >>> Query hint works in a best effort manner, so if users specifies a hint >>> with invalid option, the query plan keeps unchanged, e.g., use >>> LOOKUP('table'='customer', 'async'='true'), but backend lookup source only >>> implemented the sync lookup function, then the async lookup hint takes no >>> effect. >>> >>> For these connectors which can have both capabilities of async and sync >>> lookup, our advice for the connector developer is implementing both sync >>> and async interfaces if both capabilities have suitable use cases, and the >>> planner can decide which capability is the preferable one based on cost >>> model or maybe other mechanism (another use case is exactly what we're >>> discussing here, users can give the query hint), otherwise choose one >>> interface to implement. >>> >>> Also, this should be clarified for the lookup function related APIs. >>> >>> Best, >>> Lincoln Lee >>> >>> >>> Jingsong Li <jingsongl...@gmail.com> 于2022年6月1日周三 15:18写道： >>> >>>> Hi Lincoln, >>>> >>>> > It's better making decisions at the query level when a connector has >>>> both >>>> capabilities. >>>> >>>> Can you clarify the mechanism? >>>> - only sync connector: What connector developers should do >>>> - only async connector: What connector developers should do >>>> - both async and sync connector: What connector developers should do >>>> >>>> Best, >>>> Jingsong >>>> >>>> On Wed, Jun 1, 2022 at 2:29 PM Lincoln Lee <lincoln.8...@gmail.com> >>>> wrote: >>>> >>>> > Hi Jingsong, >>>> > >>>> > Thanks for your feedback! >>>> > >>>> > Yes, the existing HBase connector use an option 'lookup.async' to >>>> control >>>> > its lookup source implementations that exposed to the planner, >>>> however it's >>>> > a private option for the HBase connector only, so it will not affect >>>> the >>>> > common API. >>>> > >>>> > And as discussed in the mailing thread of FLIP-221[1], we got a >>>> consensus >>>> > that do not make it as a common option. It's better making decisions >>>> at the >>>> > query level when a connector has both capabilities. >>>> > >>>> > So if everything goes well, we should discuss it whether to deprecate >>>> > the 'lookup.async' >>>> > or not for HBase connector after the hint been done. >>>> > >>>> > This will be mentioned in the Compatibility part of this FLIP[2]. >>>> > >>>> > WDYT? >>>> > >>>> > [1]: https://lists.apache.org/thread/v76g8v1o9sjdho9kbzlgjyv38l2oynox >>>> > [2]: >>>> > >>>> > >>>> https://cwiki.apache.org/confluence/display/FLINK/FLIP-234%3A+Support+Retryable+Lookup+Join+To+Solve+Delayed+Updates+Issue+In+External+Systems?src=contextnavpagetreemode >>>> > >>>> > Best, >>>> > Lincoln Lee >>>> > >>>> > >>>> > Jingsong Li <jingsongl...@gmail.com> 于2022年6月1日周三 14:11写道： >>>> > >>>> > > Hi Lincoln, >>>> > > >>>> > > The unified lookup hint is what I want. >>>> > > >>>> > > And I like 'async'='true|false' option. >>>> > > >>>> > > But there is a compatibility issue, as I remember if async is >>>> currently >>>> > > controlled by connector, and this may also require some API changes? >>>> > > >>>> > > We need to have a clear story for the connector combined with this >>>> > option: >>>> > > - only sync connector >>>> > > - only async connector >>>> > > - both async and sync connector >>>> > > >>>> > > Best, >>>> > > Jingsong >>>> > > >>>> > > On Mon, May 30, 2022 at 3:55 PM Lincoln Lee <lincoln.8...@gmail.com >>>> > >>>> > > wrote: >>>> > > >>>> > > > Thanks Jark for your quick response and the consensus! >>>> > > > >>>> > > > And I will update the FLIP after Jingsong or other developers >>>> confirm >>>> > > that >>>> > > > there is no problem. >>>> > > > >>>> > > > Best, >>>> > > > Lincoln Lee >>>> > > > >>>> > > > >>>> > > > Jark Wu <imj...@gmail.com> 于2022年5月30日周一 15:49写道： >>>> > > > >>>> > > > > Thanks for the update. >>>> > > > > >>>> > > > > The unified lookup hint looks good to me. >>>> > > > > And thanks for explaining ALLOW_UNORDERED. >>>> > > > > >>>> > > > > Best, >>>> > > > > Jark >>>> > > > > >>>> > > > > On Mon, 30 May 2022 at 15:31, Lincoln Lee < >>>> lincoln.8...@gmail.com> >>>> > > > wrote: >>>> > > > > >>>> > > > > > Hi Jark & Jingsong, >>>> > > > > > >>>> > > > > > Thanks for your feedback! >>>> > > > > > >>>> > > > > > 1.) support retry on sync lookup >>>> > > > > > I also agree with supporting it, this will be useful for >>>> connectors >>>> > > > that >>>> > > > > > don't have asynchronous lookup implementations and can also >>>> solve >>>> > the >>>> > > > > ASYNC >>>> > > > > > non-target problem to some extent(because the retrying is >>>> blocking >>>> > > for >>>> > > > > sync >>>> > > > > > lookup, and may accumulate delay, but it maybe acceptable for >>>> the >>>> > > case >>>> > > > > that >>>> > > > > > most or all data want to do a delayed lookup). >>>> > > > > > >>>> > > > > > For the api perspective, we can do some unification. Let's >>>> think of >>>> > > the >>>> > > > > > whole user story for lookup join: >>>> > > > > > >>>> > > > > > ASYNC_LOOKUP vs SYNC_LOOKUP can share a common one: LOOKUP by >>>> > > > different >>>> > > > > > hint option values: 'async'='true|false' >>>> > > > > > >>>> > > > > > ASYNC_LOOKUP_MISS_RETRY vs SYNC_LOOKUP_MISS_RETRY can share >>>> the >>>> > > > > > LOOKUP_MISS_RETRY with hint option: 'miss-retry'='true|false' >>>> > > > > > >>>> > > > > > we can use one single hint LOOKUP with different hint options >>>> > > > > > ('async'='true|false', 'miss-retry'='true|false') to cover all >>>> > > related >>>> > > > > > functionalities. >>>> > > > > > Compared to multiple hints with different subsets of >>>> > functionality, a >>>> > > > > > single hint may be easier for users to understand and use, and >>>> > > specific >>>> > > > > > parameters can be quickly found through documentation >>>> > > > > > >>>> > > > > > the support matrix will be: >>>> > > > > > lookup support async retry >>>> > > > > > sync w/o retry N N >>>> > > > > > sync w/ retry N Y >>>> > > > > > async w/o retry Y N >>>> > > > > > async w/ retry Y Y >>>> > > > > > >>>> > > > > > and the available hint options for each mode: >>>> > > > > > mode support hint options >>>> > > > > > async async'='true' >>>> > > > > > 'output-mode'='ordere|allow-unordered' >>>> > > > > > 'capacity'='100' >>>> > > > > > 'timeout'='180s' >>>> > > > > > retry miss-retry'='true' >>>> > > > > > 'retry-strategy'='fixed-delay' >>>> > > > > > 'delay'='10s' >>>> > > > > > 'max-attempts'='3' >>>> > > > > > >>>> > > > > > >>>> > > > > > 2.) 'allow-unordered' vs 'unordered' for >>>> > > > > > 'table.exec.async-lookup.output-mode' >>>> > > > > > Yes, make it align with DataStream Api maybe more intuitive, >>>> but >>>> > > > there's >>>> > > > > > some difference in table layer that makes the >>>> 'allow-unordered' >>>> > > > > meaningful: >>>> > > > > > updates in the pipeline need to be processed in order, >>>> > > ALLOW_UNORDERED >>>> > > > > > means if users allow unordered result, it will attempt to use >>>> > > > > > AsyncDataStream.OutputMode.UNORDERED when it does not affect >>>> the >>>> > > > > > correctness of the result, otherwise ORDERED will be still >>>> used. >>>> > > > > > >>>> > > > > > Another choice is that when the user specifies unordered mode, >>>> > > planner >>>> > > > > > throws an error when it finds that it may affect correctness. >>>> But >>>> > > this >>>> > > > is >>>> > > > > > not user-friendly and is not consistent with the customary >>>> > treatment >>>> > > of >>>> > > > > > invalid query hints(best effort). >>>> > > > > > >>>> > > > > > I opened a pr https://github.com/apache/flink/pull/19759 for >>>> the >>>> > new >>>> > > > > > option >>>> > > > > > 'table.exec.async-lookup.output-mode' and also a discussion on >>>> > > > > FLINK-27625: >>>> > > > > > add query hint 'ASYNC_LOOKUP' for async lookup join(Since the >>>> > changes >>>> > > > > were >>>> > > > > > relatively minor, no new flip was created) >>>> > > > > > >>>> > > > > > If we can reach a consensus on the single unified hint, e.g., >>>> > LOOKUP, >>>> > > > > then >>>> > > > > > FLINK-27625 can be covered. >>>> > > > > > >>>> > > > > > WDYT? >>>> > > > > > >>>> > > > > > Best, >>>> > > > > > Lincoln Lee >>>> > > > > > >>>> > > > > > >>>> > > > > > Jark Wu <imj...@gmail.com> 于2022年5月27日周五 21:04写道： >>>> > > > > > >>>> > > > > > > Hi Lincoln, >>>> > > > > > > >>>> > > > > > > Delayed Dim Join is a frequently requested feature, it's >>>> exciting >>>> > > to >>>> > > > > see >>>> > > > > > > this feature is on the road. >>>> > > > > > > The FLIP looks good to me in general. I only left some minor >>>> > > > comments. >>>> > > > > > > >>>> > > > > > > 1) support retry for sync lookup >>>> > > > > > > I'm also fine with the idea proposed by Jingsong. But this >>>> > doesn't >>>> > > > > > conflict >>>> > > > > > > with the FLIP and can >>>> > > > > > > be future work. It would be great if we can determine the >>>> APIs >>>> > > first. >>>> > > > > > > >>>> > > > > > > 1) "allow-unordered" => "unordered" >>>> > > > > > > I would prefer the "unordered" output mode rather than >>>> > > > > "allow-unordered". >>>> > > > > > > Because this fully aligns with the DataStream behaviors and >>>> > avoids >>>> > > > > > > confusion on the differences. >>>> > > > > > > I understand the purpose that adding a "allow" prefix here, >>>> but I >>>> > > > think >>>> > > > > > the >>>> > > > > > > semantic is fine to just >>>> > > > > > > use "unordered" here. We didn't see any users confused about >>>> > > > > > > OutputMode#UNORDERED. >>>> > > > > > > >>>> > > > > > > Best, >>>> > > > > > > Jark >>>> > > > > > > >>>> > > > > > > >>>> > > > > > > >>>> > > > > > > On Fri, 27 May 2022 at 12:58, Jingsong Li < >>>> > jingsongl...@gmail.com> >>>> > > > > > wrote: >>>> > > > > > > >>>> > > > > > > > Thanks Lincoln for your proposal. >>>> > > > > > > > >>>> > > > > > > > Take a look at `strategy: fixed-delay delay: duration, >>>> e.g., >>>> > 10s >>>> > > > > > > > max-attempts: integer, e.g., 3`. >>>> > > > > > > > >>>> > > > > > > > Are these options only for async? It looks like normal >>>> lookups >>>> > > work >>>> > > > > > too? >>>> > > > > > > > >>>> > > > > > > > One thing is: most of the lookup functions seem to be >>>> > synchronous >>>> > > > > now? >>>> > > > > > > > There are not so many asynchronous ones? >>>> > > > > > > > >>>> > > > > > > > Best, >>>> > > > > > > > Jingsong >>>> > > > > > > > >>>> > > > > > > > On Tue, May 24, 2022 at 11:48 AM Lincoln Lee < >>>> > > > lincoln.8...@gmail.com >>>> > > > > > >>>> > > > > > > > wrote: >>>> > > > > > > > >>>> > > > > > > > > Hi all, >>>> > > > > > > > > >>>> > > > > > > > > Considering the new common table option >>>> 'lookup.max-retries' >>>> > > > > proposed >>>> > > > > > > in >>>> > > > > > > > > FLIP-221[1] which is commonly used for exception >>>> handling in >>>> > > > > > connector >>>> > > > > > > > > implementation, we should clearly distinguish >>>> > > ASYNC_LOOKUP_RETRY >>>> > > > > from >>>> > > > > > > it >>>> > > > > > > > to >>>> > > > > > > > > avoid confusing users. >>>> > > > > > > > > >>>> > > > > > > > > To do so, the name ASYNC_LOOKUP_RETRY can change to >>>> > > > > > > > > ASYNC_LOOKUP_MISS_RETRY, and as the name implies, >>>> restrict >>>> > it >>>> > > to >>>> > > > > > > support >>>> > > > > > > > > retries only for lookup misses and no longer include >>>> > exceptions >>>> > > > > (for >>>> > > > > > > sql >>>> > > > > > > > > connectors, let the connector implementer decide how to >>>> > handle >>>> > > > > > > exceptions >>>> > > > > > > > > since there are various kinds of retryable exceptions >>>> and can >>>> > > not >>>> > > > > > retry >>>> > > > > > > > > ones). >>>> > > > > > > > > >>>> > > > > > > > > The FLIP[2] has been updated. >>>> > > > > > > > > >>>> > > > > > > > > [1] >>>> > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > >>>> > > > > > > >>>> > > > > > >>>> > > > > >>>> > > > >>>> > > >>>> > >>>> https://cwiki.apache.org/confluence/display/FLINK/FLIP-221%3A+Abstraction+for+lookup+source+cache+and+metric >>>> > > > > > > > > [2] >>>> > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > >>>> > > > > > > >>>> > > > > > >>>> > > > > >>>> > > > >>>> > > >>>> > >>>> https://cwiki.apache.org/confluence/display/FLINK/FLIP-234%3A+Support+Retryable+Lookup+Join+To+Solve+Delayed+Updates+Issue+In+External+Systems >>>> > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > > Best, >>>> > > > > > > > > Lincoln Lee >>>> > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > > Lincoln Lee <lincoln.8...@gmail.com> 于2022年5月19日周四 >>>> 18:24写道： >>>> > > > > > > > > >>>> > > > > > > > > > Dear Flink developers, >>>> > > > > > > > > > >>>> > > > > > > > > > I would like to open a discussion on FLIP 234 [1] to >>>> > support >>>> > > > > > > retryable >>>> > > > > > > > > > lookup join to solve delayed updates issue, as a >>>> pre-work >>>> > for >>>> > > > > this >>>> > > > > > > > > > solution, we proposed FLIP-232[2] which adds a generic >>>> > retry >>>> > > > > > support >>>> > > > > > > > for >>>> > > > > > > > > > Async I/O. >>>> > > > > > > > > > We prefer to offer this retry capability via query >>>> hints, >>>> > > > similar >>>> > > > > > to >>>> > > > > > > > new >>>> > > > > > > > > > join hints proposed in FLINK-27625[3] & FLIP-204[4]. >>>> > > > > > > > > > >>>> > > > > > > > > > This feature is backwards compatible and >>>> transparently to >>>> > > > > > connectors. >>>> > > > > > > > For >>>> > > > > > > > > > existing connectors which implements >>>> AsyncTableFunction, >>>> > can >>>> > > > > easily >>>> > > > > > > > > enable >>>> > > > > > > > > > async retry via the new join hint. >>>> > > > > > > > > > >>>> > > > > > > > > > [1] >>>> > > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > >>>> > > > > > > >>>> > > > > > >>>> > > > > >>>> > > > >>>> > > >>>> > >>>> https://cwiki.apache.org/confluence/display/FLINK/FLIP-234%3A+Support+Retryable+Lookup+Join+To+Solve+Delayed+Updates+Issue+In+External+Systems >>>> > > > > > > > > > [2] >>>> > > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > >>>> > > > > > > >>>> > > > > > >>>> > > > > >>>> > > > >>>> > > >>>> > >>>> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=211883963 >>>> > > > > > > > > > [3] >>>> > > > > > >>>> https://lists.apache.org/thread/jm9kg33wk9z2bvo2b0g5bp3n5kfj6qv8 >>>> > > > > > > > > > [4] >>>> > > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > >>>> > > > > > > >>>> > > > > > >>>> > > > > >>>> > > > >>>> > > >>>> > >>>> https://cwiki.apache.org/confluence/display/FLINK/FLIP-204:+Introduce+Hash+Lookup+Join >>>> > > > > > > > > > >>>> > > > > > > > > > Best, >>>> > > > > > > > > > Lincoln Lee >>>> > > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > >>>> > > > > > > >>>> > > > > > >>>> > > > > >>>> > > > >>>> > > >>>> > >>>> >>>
