Hi here, Sorry for digging up this old email.
May I consult one question about what's the final behavior we expected after we enabled retryable mechanism. I viewed the FLIP-232 & FLIP-234, but I didn't get a clear answer as lacking of some knowledge. Let me take a example there, let's assume we have a dim table(id, price), the record(id1) existed in dim table before 10:00, and then it was updated in business system at 10:01, but delay updated in dim table at 10:02. the record timeline as follow: 10:00 -> (id1, 10) 10:00 -> the id1 records was been updated, but delayed persistency or sync to dim table. 10:02 -> (id1, 12) And a Flink application processes an order record that will join the dim table at 10:01, so it will output an event +[order1, id1, 10]. And if we enable retry mechanism no matter it's sync or async, does it mean there will be two events sink to downstream: 1. retract event: -[order1, id1, 10] 2. new event: +[order1, id1, 12] does the above all behavior is what we expected to solve the delay update for dimension table? Lincoln Lee <lincoln.8...@gmail.com> 于2022年6月7日周二 12:19写道： > 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 > >>>> > > > > > > > > > > >>>> > > > > > > > > > >>>> > > > > > > > > >>>> > > > > > > > >>>> > > > > > > >>>> > > > > > >>>> > > > > >>>> > > > >>>> > > >>>> > >>> >
