Hi Aitozi, Thanks for your updates!
By the design of hints, the hints after select clause belong to the query hints category, and this new hint is also a kind of join hints[1]. Join table function is one of the join type defined by flink sql joins[2], all existing join hints[1] omit the 'join' keyword, so I would prefer the 'ASYNC_TABLE_FUNC' (which is actually the one for 'ASYNC_TABLE_FUNC_JOIN'). Since a short Chinese holiday is coming, I suggest waiting for other people's responses before continuing to vote (next monday?) Btw, I discussed with @fudian offline about pyflink support, there should be no known issues, so you can create a subtask with pyflink support after the vote passed. [1] https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/sql/queries/hints/#join-hints [2] https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/sql/queries/joins/ Best, Lincoln Lee Aitozi <gjying1...@gmail.com> 于2023年6月18日周日 21:18写道： > Hi all, > Sorry for the late reply, I have a discussion with Lincoln offline, > mainly about > the naming of the hints option. Thanks Lincoln for the valuable > suggestions. > > Let me answer the last email inline. > > >For `JavaAsyncTableFunc0` in flip, can you use a scenario like RPC call as > an example? > > Sure, will give an example when adding the doc of async udtf and will > update the FLIP simultaneously > > >For the name of this query hint, 'LATERAL' (include its internal options) > don't show any relevance to async, but I haven't thought of a suitable name > at the moment, > > After some discussion with Lincoln, We prefer to choose one of the > `ASYNC_TABLE_FUNC` and `ASYNC_LATERAL`. > Besides, In my opinion the keyword `lateral`'s use scenario is wider than > the table function join, but in this case we only want to config > the async table function, So I'm a bit more lean to the `ASYNC_TABLE_FUNC`. > Looking forward to some inputs if you guys have > some better suggestion on the naming. > > For the usage of the hints config option, I have updated the section > of ConfigOption, you can refer to the FLIP > for more details. > > >Also, the terms 'correlate join' and 'lateral join' are not the same as in > the current joins page[1], so maybe it would be better if we unified them > into 'join table function' > > Yes, we should unified to the 'join table function', updated. > > Best, > Aitozi > > Lincoln Lee <lincoln.8...@gmail.com> 于2023年6月15日周四 09:15写道： > > > Hi Aitozi, > > > > Thanks for your reply! Gives sql users more flexibility to get > > asynchronous processing capabilities via lateral join table function +1 > for > > this > > > > For `JavaAsyncTableFunc0` in flip, can you use a scenario like RPC call > as > > an example? > > > > For the name of this query hint, 'LATERAL' (include its internal options) > > don't show any relevance to async, but I haven't thought of a suitable > name > > at the moment, > > maybe we need to highlight the async keyword directly, we can also see if > > others have better candidates > > > > For the hint option "timeout = '180s'" should be "'timeout' = '180s'", > > seems a typo in the flip. And use upper case for all keywords in sql > > examples. > > Also, the terms 'correlate join' and 'lateral join' are not the same as > in > > the current joins page[1], so maybe it would be better if we unified them > > into 'join table function' > > > > [1] > > > > > https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/sql/queries/joins/#table-function > > > > Best, > > Lincoln Lee > > > > > > Aitozi <gjying1...@gmail.com> 于2023年6月14日周三 16:11写道： > > > > > Hi Lincoln > > > > > > Very thanks for your valuable question. I will try to answer your > > > questions inline. > > > > > > >Does the async udtf bring any additional benefits besides a > > > lighter implementation？ > > > > > > IMO, async udtf is more than a lighter implementation. It can act as a > > > general way for sql users to use the async operator. And they don't > have > > to > > > bind the async function with a table (a LookupTable), and they are not > > > forced to join on an equality join condition, and they can use it to do > > > more than enrich data. > > > > > > The async lookup join is more like a subset/specific usage of async > udtf. > > > The specific version has more opportunity to be optimized (like push > > down) > > > is acceptable. Async table function should be categorized to > used-defined > > > function. > > > > > > >Should users > > > > > > migrate to the lookup source when they encounter similar requirements > or > > > > > > problems, or should we develop an additional set of similar mechanisms？ > > > > > > As I clarified above, the lookup join is a specific usage of async > udtf. > > So > > > it deserves more refined optimization like caching / retryable. But it > > may > > > not all > > > > > > suitable for the async udtf. As function, it can be deterministic/or > > > non-deterministic. So caching is not suitable, and we also do not have > a > > > common cache for the udf now. So I think optimization like > caching/retry > > > should be handed over to the function implementor. > > > > > > > the newly added query hint need a different name that > > > can be easier related to the lateral operation as the current join > > hints[5] > > > do. > > > > > > > > > What about using LATERAL? > > > > > > as below > > > > > > SELECT /*+ LATERAL('output-mode' = 'ordered', 'capacity' = '200', > > timeout = > > > '180s') */ a, c1, c2 > > > > > > FROM T1 > > > > > > LEFT JOIN lateral TABLE (async_split(b)) AS T(c1, c2) ON true > > > > > > >For the async func example, since the target scenario is an external > io > > > operation, it's better to add the `close` method to actively release > > > resources as a good example for users > > > > > > > > > Make sense to me, will update the FLIP > > > > > > Best, > > > > > > Aitozi. > > > > > > Lincoln Lee <lincoln.8...@gmail.com> 于2023年6月14日周三 14:24写道： > > > > > > > Hi Aitozi, > > > > > > > > Sorry for the lately reply here! Supports async > > > udtf(`AsyncTableFunction`) > > > > directly in sql seems like an attractive feature, but there're two > > issues > > > > that need to be addressed before we can be sure to add it: > > > > 1. As mentioned in the flip[1], the current lookup function can > already > > > > implement the requirements, but it requires implementing an extra > > > > `LookupTableSource` and explicitly declaring the table schema (which > > can > > > > help implementers the various push-down optimizations supported by > the > > > > planner). Does the async udtf bring any additional benefits besides a > > > > lighter implementation? > > > > 2. FLIP-221[2] abstracts a reusable cache and metric infrastructure > for > > > > lookup sources, which are important to improve performance and > > > > observability for high overhead external io scenarios, how do we > > > integrate > > > > and reuse these capabilities after introducing async udtf? Should > users > > > > migrate to the lookup source when they encounter similar requirements > > or > > > > problems, or should we develop an additional set of similar > mechanisms? > > > (a > > > > similarly case: FLIP-234[3] introduced the retryable capability for > > > lookup > > > > join) > > > > > > > > For the flip itself, > > > > 1. Considering the 'options' is already used as the dynamic table > > > > options[4] in flink, the newly added query hint need a different name > > > that > > > > can be easier related to the lateral operation as the current join > > > hints[5] > > > > do. > > > > 2. For the async func example, since the target scenario is an > external > > > io > > > > operation, it's better to add the `close` method to actively release > > > > resources as a good example for users. Also in terms of the > determinism > > > of > > > > a function, it is important to remind users that unless the behavior > of > > > the > > > > function is deterministic, it needs to be explicitly declared as > > > > non-deterministic. > > > > > > > > [1]. > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-313%3A+Add+support+of+User+Defined+AsyncTableFunction?src=contextnavpagetreemode > > > > [2]. > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-221%3A+Abstraction+for+lookup+source+cache+and+metric?src=contextnavpagetreemode > > > > [3]. > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-234%3A+Support+Retryable+Lookup+Join+To+Solve+Delayed+Updates+Issue+In+External+Systems?src=contextnavpagetreemode > > > > [4]. > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-113%3A+Supports+Dynamic+Table+Options+for+Flink+SQL?src=contextnavpagetreemode > > > > [5]. > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-229%3A+Introduces+Join+Hint+for+Flink+SQL+Batch+Job?src=contextnavpagetreemode > > > > > > > > Best, > > > > Lincoln Lee > > > > > > > > > > > > Aitozi <gjying1...@gmail.com> 于2023年6月13日周二 11:30写道： > > > > > > > > > Get your meaning now, thanks :) > > > > > > > > > > Best, > > > > > Aitozi. > > > > > > > > > > Feng Jin <jinfeng1...@gmail.com> 于2023年6月13日周二 11:16写道： > > > > > > > > > > > Hi Aitozi, > > > > > > > > > > > > Sorry for the confusing description. > > > > > > > > > > > > What I meant was that if we need to remind users about tire > safety > > > > > issues, > > > > > > we should introduce the new UDTF interface instead of executing > the > > > > > > original UDTF asynchronously. Therefore, I agree with introducing > > the > > > > > > AsyncTableFunction. > > > > > > > > > > > > Best, > > > > > > Feng > > > > > > > > > > > > On Tue, Jun 13, 2023 at 10:42 AM Aitozi <gjying1...@gmail.com> > > > wrote: > > > > > > > > > > > > > Hi Feng, > > > > > > > Thanks for your question. We do not provide a way to switch > > the > > > > > UDTF > > > > > > > between sync and async way, > > > > > > > So there should be no thread safety problem here. > > > > > > > > > > > > > > Best, > > > > > > > Aitozi > > > > > > > > > > > > > > Feng Jin <jinfeng1...@gmail.com> 于2023年6月13日周二 10:31写道： > > > > > > > > > > > > > > > Hi Aitozi, We do need to remind users about thread safety > > issues. > > > > > Thank > > > > > > > you > > > > > > > > for your efforts on this FLIP. I have no further questions. > > > > > > > > Best, Feng > > > > > > > > > > > > > > > > > > > > > > > > On Tue, Jun 13, 2023 at 6:05 AM Jing Ge > > > <j...@ververica.com.invalid > > > > > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > Hi Aitozi, > > > > > > > > > > > > > > > > > > Thanks for taking care of that part. I have no other > concern. > > > > > > > > > > > > > > > > > > Best regards, > > > > > > > > > Jing > > > > > > > > > > > > > > > > > > > > > > > > > > > On Mon, Jun 12, 2023 at 5:38 PM Aitozi < > gjying1...@gmail.com > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > BTW, If there are no other more blocking issue / > comments, > > I > > > > > would > > > > > > > like > > > > > > > > > to > > > > > > > > > > start a VOTE in another thread this wednesday 6.14 > > > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > Aitozi. > > > > > > > > > > > > > > > > > > > > Aitozi <gjying1...@gmail.com> 于2023年6月12日周一 23:34写道： > > > > > > > > > > > > > > > > > > > > > Hi, Jing, > > > > > > > > > > > Thanks for your explanation. I get your point now. > > > > > > > > > > > > > > > > > > > > > > For the performance part, I think it's a good idea to > run > > > > with > > > > > > > > > returning > > > > > > > > > > a > > > > > > > > > > > big table case, the memory consumption > > > > > > > > > > > should be a point to be taken care about. Because in > the > > > > > ordered > > > > > > > > mode, > > > > > > > > > > the > > > > > > > > > > > head element in buffer may affect the > > > > > > > > > > > total memory consumption. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > > Aitozi. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Jing Ge <j...@ververica.com.invalid> 于2023年6月12日周一 > > > 20:28写道： > > > > > > > > > > > > > > > > > > > > > >> Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > > >> Which key will be used for lookup is not an issue, > only > > > one > > > > > row > > > > > > > will > > > > > > > > > be > > > > > > > > > > >> required for each key in order to enrich it. True, it > > > > depends > > > > > on > > > > > > > the > > > > > > > > > > >> implementation whether multiple rows or single row for > > > each > > > > > key > > > > > > > will > > > > > > > > > be > > > > > > > > > > >> returned. However, for the lookup & enrichment > scenario, > > > one > > > > > > > row/key > > > > > > > > > is > > > > > > > > > > >> recommended, otherwise, like I mentioned previously, > > > > > enrichment > > > > > > > > won't > > > > > > > > > > >> work. > > > > > > > > > > >> > > > > > > > > > > >> I am a little bit concerned about returning a big > table > > > for > > > > > each > > > > > > > > key, > > > > > > > > > > >> since > > > > > > > > > > >> it will take the async call longer to return and need > > more > > > > > > memory. > > > > > > > > The > > > > > > > > > > >> performance tests should cover this scenario. This is > > not > > > a > > > > > > > blocking > > > > > > > > > > issue > > > > > > > > > > >> for this FLIP. > > > > > > > > > > >> > > > > > > > > > > >> Best regards, > > > > > > > > > > >> Jing > > > > > > > > > > >> > > > > > > > > > > >> On Sat, Jun 10, 2023 at 4:11 AM Aitozi < > > > > gjying1...@gmail.com> > > > > > > > > wrote: > > > > > > > > > > >> > > > > > > > > > > >> > Hi Jing, > > > > > > > > > > >> > I means the join key is not necessary to be the > > > > primary > > > > > > key > > > > > > > or > > > > > > > > > > >> unique > > > > > > > > > > >> > index of the database. > > > > > > > > > > >> > In this situation, we may queried out multi rows for > > one > > > > > join > > > > > > > > key. I > > > > > > > > > > >> think > > > > > > > > > > >> > that's why the > > > > > > > > > > >> > LookupFunction#lookup will return a collection of > > > RowData. > > > > > > > > > > >> > > > > > > > > > > > >> > BTW, I think the behavior of lookup join will not > > affect > > > > the > > > > > > > > > semantic > > > > > > > > > > of > > > > > > > > > > >> > the async udtf. > > > > > > > > > > >> > We use the Async TableFunction here and the table > > > function > > > > > can > > > > > > > > > collect > > > > > > > > > > >> > multiple rows. > > > > > > > > > > >> > > > > > > > > > > > >> > Thanks, > > > > > > > > > > >> > Atiozi. > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > Jing Ge <j...@ververica.com.invalid> 于2023年6月10日周六 > > > > 00:15写道： > > > > > > > > > > >> > > > > > > > > > > > >> > > Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > > > > >> > > The keyRow used in this case contains all keys[1]. > > > > > > > > > > >> > > > > > > > > > > > > >> > > Best regards, > > > > > > > > > > >> > > Jing > > > > > > > > > > >> > > > > > > > > > > > > >> > > [1] > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://github.com/apache/flink/blob/191ec6ca3943d7119f14837efe112e074d815c47/flink-table/flink-table-common/src/main/java/org/apache/flink/table/functions/LookupFunction.java#L49 > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > On Fri, Jun 9, 2023 at 3:42 PM Aitozi < > > > > > gjying1...@gmail.com > > > > > > > > > > > > > > > > wrote: > > > > > > > > > > >> > > > > > > > > > > > > >> > > > Hi Jing, > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > The performance test is added to the FLIP. > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > As I know, The lookup join can return multi > > > rows, > > > > > it > > > > > > > > > depends > > > > > > > > > > on > > > > > > > > > > >> > > > whether the join key > > > > > > > > > > >> > > > is the primary key of the external database or > > not. > > > > The > > > > > > > > `lookup` > > > > > > > > > > [1] > > > > > > > > > > >> > will > > > > > > > > > > >> > > > return a collection of > > > > > > > > > > >> > > > joined result, and each of them will be > collected > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > [1]: > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://github.com/apache/flink/blob/191ec6ca3943d7119f14837efe112e074d815c47/flink-table/flink-table-common/src/main/java/org/apache/flink/table/functions/LookupFunction.java#L52 > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > Thanks, > > > > > > > > > > >> > > > Aitozi. > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > Jing Ge <j...@ververica.com.invalid> > 于2023年6月9日周五 > > > > > > 17:05写道： > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > Thanks for the feedback. Looking forward to > the > > > > > > > performance > > > > > > > > > > tests. > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > Afaik, lookup returns one row for each key [1] > > > [2]. > > > > > > > > > > Conceptually, > > > > > > > > > > >> the > > > > > > > > > > >> > > > > lookup function is used to enrich column(s) > from > > > the > > > > > > > > dimension > > > > > > > > > > >> table. > > > > > > > > > > >> > > If, > > > > > > > > > > >> > > > > for the given key, there will be more than one > > > row, > > > > > > there > > > > > > > > will > > > > > > > > > > be > > > > > > > > > > >> no > > > > > > > > > > >> > > way > > > > > > > > > > >> > > > to > > > > > > > > > > >> > > > > know which row will be used to enrich the key. > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > [1] > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://github.com/apache/flink/blob/191ec6ca3943d7119f14837efe112e074d815c47/flink-table/flink-table-common/src/main/java/org/apache/flink/table/functions/LookupFunction.java#L49 > > > > > > > > > > >> > > > > [2] > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://github.com/apache/flink/blob/191ec6ca3943d7119f14837efe112e074d815c47/flink-table/flink-table-common/src/main/java/org/apache/flink/table/functions/TableFunction.java#L196 > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > Best regards, > > > > > > > > > > >> > > > > Jing > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > On Fri, Jun 9, 2023 at 5:18 AM Aitozi < > > > > > > > gjying1...@gmail.com > > > > > > > > > > > > > > > > > > > >> wrote: > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > Hi Jing > > > > > > > > > > >> > > > > > Thanks for your good questions. I have > > > updated > > > > > the > > > > > > > > > example > > > > > > > > > > >> to > > > > > > > > > > >> > the > > > > > > > > > > >> > > > > FLIP. > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > Only one row for each lookup > > > > > > > > > > >> > > > > > lookup can also return multi rows, based on > > the > > > > > query > > > > > > > > > result. > > > > > > > > > > >> [1] > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > [1]: > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://github.com/apache/flink/blob/191ec6ca3943d7119f14837efe112e074d815c47/flink-table/flink-table-common/src/main/java/org/apache/flink/table/functions/LookupFunction.java#L56 > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > If we use async calls with lateral join, > my > > > gut > > > > > > > feeling > > > > > > > > is > > > > > > > > > > >> > > > > > that we might have many more async calls > than > > > > lookup > > > > > > > > join. I > > > > > > > > > > am > > > > > > > > > > >> not > > > > > > > > > > >> > > > > really > > > > > > > > > > >> > > > > > sure if we will be facing potential issues > in > > > this > > > > > > case > > > > > > > or > > > > > > > > > > not. > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > IMO, the work pattern is similar to the > lookup > > > > > > function, > > > > > > > > for > > > > > > > > > > >> each > > > > > > > > > > >> > row > > > > > > > > > > >> > > > > from > > > > > > > > > > >> > > > > > the left table, > > > > > > > > > > >> > > > > > it will evaluate the eval method once, so > the > > > > async > > > > > > call > > > > > > > > > > numbers > > > > > > > > > > >> > will > > > > > > > > > > >> > > > not > > > > > > > > > > >> > > > > > change. > > > > > > > > > > >> > > > > > and the maximum calls in flight is limited > by > > > the > > > > > > Async > > > > > > > > > > >> operators > > > > > > > > > > >> > > > buffer > > > > > > > > > > >> > > > > > capacity > > > > > > > > > > >> > > > > > which will be controlled by the option. > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > BTW, for the naming of these option, I > updated > > > the > > > > > > FLIP > > > > > > > > > about > > > > > > > > > > >> this > > > > > > > > > > >> > > you > > > > > > > > > > >> > > > > can > > > > > > > > > > >> > > > > > refer to > > > > > > > > > > >> > > > > > the section of "ConfigOption" and "Rejected > > > > > > > Alternatives" > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > In the end, for the performance evaluation, > > I'd > > > > like > > > > > > to > > > > > > > do > > > > > > > > > > some > > > > > > > > > > >> > tests > > > > > > > > > > >> > > > and > > > > > > > > > > >> > > > > > will update it to the FLIP doc > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > Thanks, > > > > > > > > > > >> > > > > > Aitozi. > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > Jing Ge <j...@ververica.com.invalid> > > > 于2023年6月9日周五 > > > > > > > > 07:23写道： > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > Thanks for the clarification. The code > > example > > > > > looks > > > > > > > > > > >> > interesting. I > > > > > > > > > > >> > > > > would > > > > > > > > > > >> > > > > > > suggest adding them into the FLIP. The > > > > description > > > > > > > with > > > > > > > > > code > > > > > > > > > > >> > > examples > > > > > > > > > > >> > > > > > will > > > > > > > > > > >> > > > > > > help readers understand the motivation and > > how > > > > to > > > > > > use > > > > > > > > it. > > > > > > > > > > >> Afaiac, > > > > > > > > > > >> > > it > > > > > > > > > > >> > > > > is a > > > > > > > > > > >> > > > > > > valid feature for Flink users. > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > As we knew, lookup join is based on > temporal > > > > join, > > > > > > > i.e. > > > > > > > > > FOR > > > > > > > > > > >> > > > SYSTEM_TIME > > > > > > > > > > >> > > > > > AS > > > > > > > > > > >> > > > > > > OF which is also used in your code > example. > > > > > Temporal > > > > > > > > join > > > > > > > > > > >> > performs > > > > > > > > > > >> > > > the > > > > > > > > > > >> > > > > > > lookup based on the processing time match. > > > Only > > > > > one > > > > > > > row > > > > > > > > > for > > > > > > > > > > >> each > > > > > > > > > > >> > > > > > > lookup(afaiu, I need to check the source > > code > > > to > > > > > > > double > > > > > > > > > > >> confirm) > > > > > > > > > > >> > > will > > > > > > > > > > >> > > > > > > return for further enrichment. One the > other > > > > hand, > > > > > > > > lateral > > > > > > > > > > >> join > > > > > > > > > > >> > > will > > > > > > > > > > >> > > > > have > > > > > > > > > > >> > > > > > > sub-queries correlated with every > individual > > > > value > > > > > > of > > > > > > > > the > > > > > > > > > > >> > reference > > > > > > > > > > >> > > > > table > > > > > > > > > > >> > > > > > > from the preceding part of the query and > > each > > > > sub > > > > > > > query > > > > > > > > > will > > > > > > > > > > >> > return > > > > > > > > > > >> > > > > > > multiple rows. If we use async calls with > > > > lateral > > > > > > > join, > > > > > > > > my > > > > > > > > > > gut > > > > > > > > > > >> > > > feeling > > > > > > > > > > >> > > > > is > > > > > > > > > > >> > > > > > > that we might have many more async calls > > than > > > > > lookup > > > > > > > > > join. I > > > > > > > > > > >> am > > > > > > > > > > >> > not > > > > > > > > > > >> > > > > > really > > > > > > > > > > >> > > > > > > sure if we will be facing potential issues > > in > > > > this > > > > > > > case > > > > > > > > or > > > > > > > > > > >> not. > > > > > > > > > > >> > > > > Possible > > > > > > > > > > >> > > > > > > issues I can think of now e.g. too many > PRC > > > > calls, > > > > > > too > > > > > > > > > many > > > > > > > > > > >> async > > > > > > > > > > >> > > > calls > > > > > > > > > > >> > > > > > > processing, the sub query will return a > > table > > > > > which > > > > > > > > might > > > > > > > > > be > > > > > > > > > > >> > (too) > > > > > > > > > > >> > > > big, > > > > > > > > > > >> > > > > > and > > > > > > > > > > >> > > > > > > might cause performance issues. I would > > > suggest > > > > > > > > preparing > > > > > > > > > > some > > > > > > > > > > >> > use > > > > > > > > > > >> > > > > cases > > > > > > > > > > >> > > > > > > and running some performance tests to > check > > > it. > > > > > > These > > > > > > > > are > > > > > > > > > my > > > > > > > > > > >> > > concerns > > > > > > > > > > >> > > > > > about > > > > > > > > > > >> > > > > > > using async calls with lateral join and > I'd > > > like > > > > > to > > > > > > > > share > > > > > > > > > > with > > > > > > > > > > >> > you, > > > > > > > > > > >> > > > > happy > > > > > > > > > > >> > > > > > > to discuss with you and hear different > > > opinions, > > > > > > > > hopefully > > > > > > > > > > the > > > > > > > > > > >> > > > > > > discussion could help me understand it > more > > > > > deeply. > > > > > > > > Please > > > > > > > > > > >> > correct > > > > > > > > > > >> > > me > > > > > > > > > > >> > > > > if > > > > > > > > > > >> > > > > > I > > > > > > > > > > >> > > > > > > am wrong. > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > Best regards, > > > > > > > > > > >> > > > > > > Jing > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > On Thu, Jun 8, 2023 at 7:22 AM Aitozi < > > > > > > > > > gjying1...@gmail.com > > > > > > > > > > > > > > > > > > > > > >> > > wrote: > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > Hi Mason, > > > > > > > > > > >> > > > > > > > Thanks for your input. I think if we > > > > support > > > > > > the > > > > > > > > > user > > > > > > > > > > >> > defined > > > > > > > > > > >> > > > > async > > > > > > > > > > >> > > > > > > > table function, > > > > > > > > > > >> > > > > > > > user will be able to use it to hold a > > batch > > > > data > > > > > > > then > > > > > > > > > > >> handle it > > > > > > > > > > >> > > at > > > > > > > > > > >> > > > > one > > > > > > > > > > >> > > > > > > time > > > > > > > > > > >> > > > > > > > in the customized function. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > AsyncSink is meant for the sink > operator. > > I > > > > have > > > > > > not > > > > > > > > > > figure > > > > > > > > > > >> out > > > > > > > > > > >> > > how > > > > > > > > > > >> > > > > to > > > > > > > > > > >> > > > > > > > integrate in this case. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > Thanks, > > > > > > > > > > >> > > > > > > > Atiozi. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > Mason Chen <mas.chen6...@gmail.com> > > > > > 于2023年6月8日周四 > > > > > > > > > 12:40写道： > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > I think it makes sense to make it > easier > > > for > > > > > SQL > > > > > > > > users > > > > > > > > > > to > > > > > > > > > > >> > make > > > > > > > > > > >> > > > > RPCs. > > > > > > > > > > >> > > > > > Do > > > > > > > > > > >> > > > > > > > you > > > > > > > > > > >> > > > > > > > > think your proposal can extend to the > > > > ability > > > > > to > > > > > > > > batch > > > > > > > > > > >> data > > > > > > > > > > >> > for > > > > > > > > > > >> > > > the > > > > > > > > > > >> > > > > > > RPC? > > > > > > > > > > >> > > > > > > > > This is also another common strategy > to > > > > > increase > > > > > > > > > > >> throughput. > > > > > > > > > > >> > > > Also, > > > > > > > > > > >> > > > > > have > > > > > > > > > > >> > > > > > > > you > > > > > > > > > > >> > > > > > > > > considered solving this a bit > > differently > > > by > > > > > > > > > leveraging > > > > > > > > > > >> > Flink's > > > > > > > > > > >> > > > > > > > AsyncSink? > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > Best, > > > > > > > > > > >> > > > > > > > > Mason > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > On Mon, Jun 5, 2023 at 1:50 AM Aitozi > < > > > > > > > > > > >> gjying1...@gmail.com> > > > > > > > > > > >> > > > > wrote: > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > One more thing for discussion: > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > In our internal implementation, we > > reuse > > > > the > > > > > > > > option > > > > > > > > > > >> > > > > > > > > > > > > `table.exec.async-lookup.buffer-capacity` > > > > > and > > > > > > > > > > >> > > > > > > > > > `table.exec.async-lookup.timeout` to > > > > config > > > > > > > > > > >> > > > > > > > > > the async udtf. Do you think we > should > > > add > > > > > two > > > > > > > > extra > > > > > > > > > > >> option > > > > > > > > > > >> > > to > > > > > > > > > > >> > > > > > > > > distinguish > > > > > > > > > > >> > > > > > > > > > from the lookup option such as > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > `table.exec.async-udtf.buffer-capacity` > > > > > > > > > > >> > > > > > > > > > `table.exec.async-udtf.timeout` > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > Best, > > > > > > > > > > >> > > > > > > > > > Aitozi. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > Aitozi <gjying1...@gmail.com> > > > > 于2023年6月5日周一 > > > > > > > > 12:20写道： > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > Hi Jing, > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > what is the difference > between > > > the > > > > > RPC > > > > > > > > call > > > > > > > > > or > > > > > > > > > > >> > query > > > > > > > > > > >> > > > you > > > > > > > > > > >> > > > > > > > > mentioned > > > > > > > > > > >> > > > > > > > > > > and the lookup in a very > > > > > > > > > > >> > > > > > > > > > > general way > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > I think the RPC call or query > > service > > > is > > > > > > quite > > > > > > > > > > >> similar to > > > > > > > > > > >> > > the > > > > > > > > > > >> > > > > > > lookup > > > > > > > > > > >> > > > > > > > > > join. > > > > > > > > > > >> > > > > > > > > > > But lookup join should work > > > > > > > > > > >> > > > > > > > > > > with `LookupTableSource`. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > Let's see how we can perform an > > async > > > > RPC > > > > > > call > > > > > > > > > with > > > > > > > > > > >> > lookup > > > > > > > > > > >> > > > > join: > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > (1) Implement an > AsyncTableFunction > > > with > > > > > RPC > > > > > > > > call > > > > > > > > > > >> logic. > > > > > > > > > > >> > > > > > > > > > > (2) Implement a > `LookupTableSource` > > > > > > connector > > > > > > > > run > > > > > > > > > > with > > > > > > > > > > >> > the > > > > > > > > > > >> > > > > async > > > > > > > > > > >> > > > > > > udtf > > > > > > > > > > >> > > > > > > > > > > defined in (1). > > > > > > > > > > >> > > > > > > > > > > (3) Then define a DDL of this look > > up > > > > > table > > > > > > in > > > > > > > > SQL > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > CREATE TEMPORARY TABLE Customers ( > > > > > > > > > > >> > > > > > > > > > > id INT, > > > > > > > > > > >> > > > > > > > > > > name STRING, > > > > > > > > > > >> > > > > > > > > > > country STRING, > > > > > > > > > > >> > > > > > > > > > > zip STRING > > > > > > > > > > >> > > > > > > > > > > ) WITH ( > > > > > > > > > > >> > > > > > > > > > > 'connector' = 'custom' > > > > > > > > > > >> > > > > > > > > > > ); > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > (4) Run with the query as below: > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > SELECT o.order_id, o.total, > > c.country, > > > > > c.zip > > > > > > > > > > >> > > > > > > > > > > FROM Orders AS o > > > > > > > > > > >> > > > > > > > > > > JOIN Customers FOR SYSTEM_TIME > AS > > OF > > > > > > > > o.proc_time > > > > > > > > > > AS > > > > > > > > > > >> c > > > > > > > > > > >> > > > > > > > > > > ON o.customer_id = c.id; > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > This example is from doc > > > > > > > > > > >> > > > > > > > > > > < > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://nightlies.apache.org/flink/flink-docs-release-1.17/docs/dev/table/sql/queries/joins/#lookup-join > > > > > > > > > > >> > > > > > > > > > >.You > > > > > > > > > > >> > > > > > > > > > > can image the look up process as > an > > > > async > > > > > > RPC > > > > > > > > call > > > > > > > > > > >> > process. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > Let's see how we can perform an > > async > > > > RPC > > > > > > call > > > > > > > > > with > > > > > > > > > > >> > lateral > > > > > > > > > > >> > > > > join: > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > (1) Implement an > AsyncTableFunction > > > with > > > > > RPC > > > > > > > > call > > > > > > > > > > >> logic. > > > > > > > > > > >> > > > > > > > > > > (2) Run query with > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > Create function f1 as '...' ; > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > SELECT o.order_id, o.total, > > c.country, > > > > > c.zip > > > > > > > > FROM > > > > > > > > > > >> Orders > > > > > > > > > > >> > > > > lateral > > > > > > > > > > >> > > > > > > > table > > > > > > > > > > >> > > > > > > > > > > (f1(order_id)) as T(...); > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > As you can see, the lateral join > > > version > > > > > is > > > > > > > more > > > > > > > > > > >> simple > > > > > > > > > > >> > and > > > > > > > > > > >> > > > > > > intuitive > > > > > > > > > > >> > > > > > > > > to > > > > > > > > > > >> > > > > > > > > > > users. Users do not have to wrap a > > > > > > > > > > >> > > > > > > > > > > LookupTableSource for the purpose > of > > > > using > > > > > > > async > > > > > > > > > > udtf. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > In the end, We can also see the > user > > > > > defined > > > > > > > > async > > > > > > > > > > >> table > > > > > > > > > > >> > > > > function > > > > > > > > > > >> > > > > > > is > > > > > > > > > > >> > > > > > > > an > > > > > > > > > > >> > > > > > > > > > > enhancement of the current lateral > > > table > > > > > > join > > > > > > > > > > >> > > > > > > > > > > which only supports sync lateral > > join > > > > now. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > Best, > > > > > > > > > > >> > > > > > > > > > > Aitozi. > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > Jing Ge > <j...@ververica.com.invalid > > > > > > > > > > > 于2023年6月2日周五 > > > > > > > > > > >> > 19:37写道： > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > >> Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> Thanks for the update. Just out > of > > > > > > curiosity, > > > > > > > > > what > > > > > > > > > > is > > > > > > > > > > >> > the > > > > > > > > > > >> > > > > > > difference > > > > > > > > > > >> > > > > > > > > > >> between the RPC call or query you > > > > > mentioned > > > > > > > and > > > > > > > > > the > > > > > > > > > > >> > lookup > > > > > > > > > > >> > > > in > > > > > > > > > > >> > > > > a > > > > > > > > > > >> > > > > > > very > > > > > > > > > > >> > > > > > > > > > >> general way? Since Lateral join > is > > > used > > > > > in > > > > > > > the > > > > > > > > > > FLIP. > > > > > > > > > > >> Is > > > > > > > > > > >> > > > there > > > > > > > > > > >> > > > > > any > > > > > > > > > > >> > > > > > > > > > special > > > > > > > > > > >> > > > > > > > > > >> thought for that? Sorry for > asking > > so > > > > > many > > > > > > > > > > questions. > > > > > > > > > > >> > The > > > > > > > > > > >> > > > FLIP > > > > > > > > > > >> > > > > > > > > contains > > > > > > > > > > >> > > > > > > > > > >> limited information to understand > > the > > > > > > > > motivation. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> Best regards, > > > > > > > > > > >> > > > > > > > > > >> Jing > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> On Fri, Jun 2, 2023 at 3:48 AM > > > Aitozi < > > > > > > > > > > >> > > gjying1...@gmail.com > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > wrote: > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > Hi Jing, > > > > > > > > > > >> > > > > > > > > > >> > I have updated the proposed > > > > changes > > > > > > to > > > > > > > > the > > > > > > > > > > >> FLIP. > > > > > > > > > > >> > > IMO, > > > > > > > > > > >> > > > > > lookup > > > > > > > > > > >> > > > > > > > has > > > > > > > > > > >> > > > > > > > > > its > > > > > > > > > > >> > > > > > > > > > >> > clear > > > > > > > > > > >> > > > > > > > > > >> > async call requirement is due > to > > > its > > > > IO > > > > > > > heavy > > > > > > > > > > >> > operator. > > > > > > > > > > >> > > In > > > > > > > > > > >> > > > > our > > > > > > > > > > >> > > > > > > > > usage, > > > > > > > > > > >> > > > > > > > > > >> sql > > > > > > > > > > >> > > > > > > > > > >> > users have > > > > > > > > > > >> > > > > > > > > > >> > logic to do some RPC call or > > query > > > > the > > > > > > > > > > third-party > > > > > > > > > > >> > > service > > > > > > > > > > >> > > > > > which > > > > > > > > > > >> > > > > > > > is > > > > > > > > > > >> > > > > > > > > > >> also IO > > > > > > > > > > >> > > > > > > > > > >> > intensive. > > > > > > > > > > >> > > > > > > > > > >> > In these case, we'd like to > > > leverage > > > > > the > > > > > > > > async > > > > > > > > > > >> > function > > > > > > > > > > >> > > to > > > > > > > > > > >> > > > > > > improve > > > > > > > > > > >> > > > > > > > > the > > > > > > > > > > >> > > > > > > > > > >> > throughput. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > Thanks, > > > > > > > > > > >> > > > > > > > > > >> > Aitozi. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > Jing Ge > > <j...@ververica.com.invalid > > > > > > > > > > > > > > 于2023年6月1日周四 > > > > > > > > > > >> > > > 22:55写道： > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > Sorry for the late reply. > Would > > > you > > > > > > like > > > > > > > to > > > > > > > > > > >> update > > > > > > > > > > >> > the > > > > > > > > > > >> > > > > > > proposed > > > > > > > > > > >> > > > > > > > > > >> changes > > > > > > > > > > >> > > > > > > > > > >> > > with more details into the > FLIP > > > > too? > > > > > > > > > > >> > > > > > > > > > >> > > I got your point. It looks > > like a > > > > > > > rational > > > > > > > > > > idea. > > > > > > > > > > >> > > > However, > > > > > > > > > > >> > > > > > > since > > > > > > > > > > >> > > > > > > > > > lookup > > > > > > > > > > >> > > > > > > > > > >> > has > > > > > > > > > > >> > > > > > > > > > >> > > its clear async call > > requirement, > > > > are > > > > > > > there > > > > > > > > > any > > > > > > > > > > >> real > > > > > > > > > > >> > > use > > > > > > > > > > >> > > > > > cases > > > > > > > > > > >> > > > > > > > > that > > > > > > > > > > >> > > > > > > > > > >> > > need this change? This will > > help > > > us > > > > > > > > > understand > > > > > > > > > > >> the > > > > > > > > > > >> > > > > > motivation. > > > > > > > > > > >> > > > > > > > > After > > > > > > > > > > >> > > > > > > > > > >> all, > > > > > > > > > > >> > > > > > > > > > >> > > lateral join and temporal > > lookup > > > > > > join[1] > > > > > > > > are > > > > > > > > > > >> quite > > > > > > > > > > >> > > > > > different. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > Best regards, > > > > > > > > > > >> > > > > > > > > > >> > > Jing > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > [1] > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://github.com/apache/flink/blob/d90a72da2fd601ca4e2a46700e91ec5b348de2ad/flink-table/flink-table-common/src/main/java/org/apache/flink/table/functions/AsyncTableFunction.java#L54 > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > On Wed, May 31, 2023 at > 8:53 AM > > > > > Aitozi > > > > > > < > > > > > > > > > > >> > > > > > gjying1...@gmail.com> > > > > > > > > > > >> > > > > > > > > > wrote: > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > Hi Jing, > > > > > > > > > > >> > > > > > > > > > >> > > > What do you think about > > it? > > > > Can > > > > > > we > > > > > > > > move > > > > > > > > > > >> > forward > > > > > > > > > > >> > > > this > > > > > > > > > > >> > > > > > > > > feature? > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > Thanks, > > > > > > > > > > >> > > > > > > > > > >> > > > Aitozi. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > Aitozi < > gjying1...@gmail.com > > > > > > > > > > > > 于2023年5月29日周一 > > > > > > > > > > >> > > 09:56写道： > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > Hi Jing, > > > > > > > > > > >> > > > > > > > > > >> > > > > > "Do you mean to > > support > > > > the > > > > > > > > > > >> > > AyncTableFunction > > > > > > > > > > >> > > > > > beyond > > > > > > > > > > >> > > > > > > > the > > > > > > > > > > >> > > > > > > > > > >> > > > > LookupTableSource?" > > > > > > > > > > >> > > > > > > > > > >> > > > > Yes, I mean to support > the > > > > > > > > > > AyncTableFunction > > > > > > > > > > >> > > beyond > > > > > > > > > > >> > > > > the > > > > > > > > > > >> > > > > > > > > > >> > > > LookupTableSource. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > The "AsyncTableFunction" > is > > > the > > > > > > > > function > > > > > > > > > > with > > > > > > > > > > >> > > > ability > > > > > > > > > > >> > > > > to > > > > > > > > > > >> > > > > > > be > > > > > > > > > > >> > > > > > > > > > >> executed > > > > > > > > > > >> > > > > > > > > > >> > > > async > > > > > > > > > > >> > > > > > > > > > >> > > > > (with AsyncWaitOperator). > > > > > > > > > > >> > > > > > > > > > >> > > > > The async lookup join is > a > > > one > > > > of > > > > > > > usage > > > > > > > > > of > > > > > > > > > > >> this. > > > > > > > > > > >> > > So, > > > > > > > > > > >> > > > > we > > > > > > > > > > >> > > > > > > > don't > > > > > > > > > > >> > > > > > > > > > >> have to > > > > > > > > > > >> > > > > > > > > > >> > > > bind > > > > > > > > > > >> > > > > > > > > > >> > > > > the AyncTableFunction > with > > > > > > > > > > LookupTableSource. > > > > > > > > > > >> > > > > > > > > > >> > > > > If User-defined > > > > > AsyncTableFunction > > > > > > is > > > > > > > > > > >> supported, > > > > > > > > > > >> > > > user > > > > > > > > > > >> > > > > > can > > > > > > > > > > >> > > > > > > > > > directly > > > > > > > > > > >> > > > > > > > > > >> > use > > > > > > > > > > >> > > > > > > > > > >> > > > > lateral table syntax to > > > perform > > > > > > async > > > > > > > > > > >> operation. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > "It would be better if > > you > > > > > could > > > > > > > > > > elaborate > > > > > > > > > > >> the > > > > > > > > > > >> > > > > > proposed > > > > > > > > > > >> > > > > > > > > > changes > > > > > > > > > > >> > > > > > > > > > >> wrt > > > > > > > > > > >> > > > > > > > > > >> > > the > > > > > > > > > > >> > > > > > > > > > >> > > > > CorrelatedCodeGenerator > > with > > > > more > > > > > > > > > details" > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > In the proposal, we use > > > lateral > > > > > > table > > > > > > > > > > syntax > > > > > > > > > > >> to > > > > > > > > > > >> > > > > support > > > > > > > > > > >> > > > > > > the > > > > > > > > > > >> > > > > > > > > > async > > > > > > > > > > >> > > > > > > > > > >> > table > > > > > > > > > > >> > > > > > > > > > >> > > > > function. So the planner > > will > > > > > also > > > > > > > > treat > > > > > > > > > > this > > > > > > > > > > >> > > > > statement > > > > > > > > > > >> > > > > > > to a > > > > > > > > > > >> > > > > > > > > > >> > > > > CommonExecCorrelate node. > > So > > > > the > > > > > > > > runtime > > > > > > > > > > code > > > > > > > > > > >> > > should > > > > > > > > > > >> > > > > be > > > > > > > > > > >> > > > > > > > > > generated > > > > > > > > > > >> > > > > > > > > > >> in > > > > > > > > > > >> > > > > > > > > > >> > > > > CorrelatedCodeGenerator. > > > > > > > > > > >> > > > > > > > > > >> > > > > In > CorrelatedCodeGenerator, > > > we > > > > > will > > > > > > > > know > > > > > > > > > > the > > > > > > > > > > >> > > > > > > TableFunction's > > > > > > > > > > >> > > > > > > > > > Kind > > > > > > > > > > >> > > > > > > > > > >> of > > > > > > > > > > >> > > > > > > > > > >> > > > > `FunctionKind.Table` or > > > > > > > > > > >> > `FunctionKind.ASYNC_TABLE` > > > > > > > > > > >> > > > > > > > > > >> > > > > For > > > `FunctionKind.ASYNC_TABLE` > > > > > we > > > > > > > can > > > > > > > > > > >> generate > > > > > > > > > > >> > a > > > > > > > > > > >> > > > > > > > > > >> AsyncWaitOperator > > > > > > > > > > >> > > > > > > > > > >> > to > > > > > > > > > > >> > > > > > > > > > >> > > > > execute the async table > > > > function. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > Thanks, > > > > > > > > > > >> > > > > > > > > > >> > > > > Aitozi. > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > Jing Ge > > > > > <j...@ververica.com.invalid > > > > > > > > > > > > > > > > > >> > > 于2023年5月29日周一 > > > > > > > > > > >> > > > > > > 03:22写道： > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > >> Thanks for the > > > clarification. > > > > > The > > > > > > > > naming > > > > > > > > > > >> > "Lookup" > > > > > > > > > > >> > > > > might > > > > > > > > > > >> > > > > > > > > suggest > > > > > > > > > > >> > > > > > > > > > >> > using > > > > > > > > > > >> > > > > > > > > > >> > > it > > > > > > > > > > >> > > > > > > > > > >> > > > >> for table look up. But > > > > > > conceptually > > > > > > > > what > > > > > > > > > > the > > > > > > > > > > >> > > eval() > > > > > > > > > > >> > > > > > > method > > > > > > > > > > >> > > > > > > > > will > > > > > > > > > > >> > > > > > > > > > >> do > > > > > > > > > > >> > > > > > > > > > >> > is > > > > > > > > > > >> > > > > > > > > > >> > > to > > > > > > > > > > >> > > > > > > > > > >> > > > >> get a collection of > > > > results(Row, > > > > > > > > > RowData) > > > > > > > > > > >> from > > > > > > > > > > >> > > the > > > > > > > > > > >> > > > > > given > > > > > > > > > > >> > > > > > > > > keys. > > > > > > > > > > >> > > > > > > > > > >> How > > > > > > > > > > >> > > > > > > > > > >> > it > > > > > > > > > > >> > > > > > > > > > >> > > > will > > > > > > > > > > >> > > > > > > > > > >> > > > >> be done depends on the > > > > > > > implementation, > > > > > > > > > > i.e. > > > > > > > > > > >> you > > > > > > > > > > >> > > can > > > > > > > > > > >> > > > > > > > implement > > > > > > > > > > >> > > > > > > > > > >> your > > > > > > > > > > >> > > > > > > > > > >> > own > > > > > > > > > > >> > > > > > > > > > >> > > > >> Source[1][2]. The > example > > in > > > > the > > > > > > > FLIP > > > > > > > > > > >> should be > > > > > > > > > > >> > > > able > > > > > > > > > > >> > > > > to > > > > > > > > > > >> > > > > > > be > > > > > > > > > > >> > > > > > > > > > >> handled > > > > > > > > > > >> > > > > > > > > > >> > in > > > > > > > > > > >> > > > > > > > > > >> > > > this > > > > > > > > > > >> > > > > > > > > > >> > > > >> way. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > >> Do you mean to support > the > > > > > > > > > > AyncTableFunction > > > > > > > > > > >> > > beyond > > > > > > > > > > >> > > > > the > > > > > > > > > > >> > > > > > > > > > >> > > > LookupTableSource? > > > > > > > > > > >> > > > > > > > > > >> > > > >> It would be better if > you > > > > could > > > > > > > > > elaborate > > > > > > > > > > >> the > > > > > > > > > > >> > > > > proposed > > > > > > > > > > >> > > > > > > > > changes > > > > > > > > > > >> > > > > > > > > > >> wrt > > > > > > > > > > >> > > > > > > > > > >> > the > > > > > > > > > > >> > > > > > > > > > >> > > > >> CorrelatedCodeGenerator > > with > > > > > more > > > > > > > > > details. > > > > > > > > > > >> > > Thanks! > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > >> Best regards, > > > > > > > > > > >> > > > > > > > > > >> > > > >> Jing > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > >> [1] > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://github.com/apache/flink/blob/678370b18e1b6c4a23e5ce08f8efd05675a0cc17/flink-table/flink-table-common/src/main/java/org/apache/flink/table/connector/source/LookupTableSource.java#L64 > > > > > > > > > > >> > > > > > > > > > >> > > > >> [2] > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://github.com/apache/flink/blob/678370b18e1b6c4a23e5ce08f8efd05675a0cc17/flink-table/flink-table-common/src/main/java/org/apache/flink/table/connector/source/AsyncTableFunctionProvider.java#L49 > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > >> On Sat, May 27, 2023 at > > > > 9:48 AM > > > > > > > > Aitozi < > > > > > > > > > > >> > > > > > > > gjying1...@gmail.com > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > >> > wrote: > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > >> > Hi Jing, > > > > > > > > > > >> > > > > > > > > > >> > > > >> > Thanks for your > > > > response. > > > > > As > > > > > > > > > stated > > > > > > > > > > in > > > > > > > > > > >> > the > > > > > > > > > > >> > > > > FLIP, > > > > > > > > > > >> > > > > > > the > > > > > > > > > > >> > > > > > > > > > >> purpose > > > > > > > > > > >> > > > > > > > > > >> > of > > > > > > > > > > >> > > > > > > > > > >> > > > this > > > > > > > > > > >> > > > > > > > > > >> > > > >> > FLIP is meant to > support > > > > > > > > > > >> > > > > > > > > > >> > > > >> > user-defined async > table > > > > > > function. > > > > > > > > As > > > > > > > > > > >> > described > > > > > > > > > > >> > > > in > > > > > > > > > > >> > > > > > > flink > > > > > > > > > > >> > > > > > > > > > >> document > > > > > > > > > > >> > > > > > > > > > >> > > [1] > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > Async table functions > > are > > > > > > special > > > > > > > > > > >> functions > > > > > > > > > > >> > for > > > > > > > > > > >> > > > > table > > > > > > > > > > >> > > > > > > > > sources > > > > > > > > > > >> > > > > > > > > > >> that > > > > > > > > > > >> > > > > > > > > > >> > > > >> perform > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > a lookup. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > So end user can not > > > directly > > > > > > > define > > > > > > > > > and > > > > > > > > > > >> use > > > > > > > > > > >> > > async > > > > > > > > > > >> > > > > > table > > > > > > > > > > >> > > > > > > > > > >> function > > > > > > > > > > >> > > > > > > > > > >> > > now. > > > > > > > > > > >> > > > > > > > > > >> > > > An > > > > > > > > > > >> > > > > > > > > > >> > > > >> > user case is reported > in > > > [2] > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > So, in conclusion, no > > new > > > > > > > interface > > > > > > > > is > > > > > > > > > > >> > > > introduced, > > > > > > > > > > >> > > > > > but > > > > > > > > > > >> > > > > > > we > > > > > > > > > > >> > > > > > > > > > >> extend > > > > > > > > > > >> > > > > > > > > > >> > the > > > > > > > > > > >> > > > > > > > > > >> > > > >> > ability to support > > > > > user-defined > > > > > > > > async > > > > > > > > > > >> table > > > > > > > > > > >> > > > > function. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > [1]: > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://nightlies.apache.org/flink/flink-docs-release-1.17/docs/dev/table/functions/udfs/ > > > > > > > > > > >> > > > > > > > > > >> > > > >> > [2]: > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > https://lists.apache.org/thread/qljwd40v5ntz6733cwcdr8s4z97b343b > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > Thanks. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > Aitozi. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > Jing Ge > > > > > > > <j...@ververica.com.invalid > > > > > > > > > > > > > > > > > > > >> > > > 于2023年5月27日周六 > > > > > > > > > > >> > > > > > > > > 06:40写道： > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > Hi Aitozi, > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > Thanks for your > > > proposal. > > > > I > > > > > am > > > > > > > not > > > > > > > > > > quite > > > > > > > > > > >> > sure > > > > > > > > > > >> > > > if > > > > > > > > > > >> > > > > I > > > > > > > > > > >> > > > > > > > > > understood > > > > > > > > > > >> > > > > > > > > > >> > your > > > > > > > > > > >> > > > > > > > > > >> > > > >> > thoughts > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > correctly. You > > > described a > > > > > > > special > > > > > > > > > > case > > > > > > > > > > >> > > > > > > implementation > > > > > > > > > > >> > > > > > > > of > > > > > > > > > > >> > > > > > > > > > the > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > AsyncTableFunction > > with > > > on > > > > > > > public > > > > > > > > > API > > > > > > > > > > >> > > changes. > > > > > > > > > > >> > > > > > Would > > > > > > > > > > >> > > > > > > > you > > > > > > > > > > >> > > > > > > > > > >> please > > > > > > > > > > >> > > > > > > > > > >> > > > >> elaborate > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > your purpose of > > writing > > > a > > > > > FLIP > > > > > > > > > > >> according to > > > > > > > > > > >> > > the > > > > > > > > > > >> > > > > > FLIP > > > > > > > > > > >> > > > > > > > > > >> > > > documentation[1]? > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > Thanks! > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > [1] > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/Flink+Improvement+Proposals > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > Best regards, > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > Jing > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > On Wed, May 24, 2023 > > at > > > > > > 1:07 PM > > > > > > > > > > Aitozi < > > > > > > > > > > >> > > > > > > > > > gjying1...@gmail.com > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > wrote: > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > May I ask for some > > > > > feedback > > > > > > > :D > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > Thanks, > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > Aitozi > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > Aitozi < > > > > > > gjying1...@gmail.com> > > > > > > > > > > >> > > 于2023年5月23日周二 > > > > > > > > > > >> > > > > > > 19:14写道： > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > Just catch an > user > > > > case > > > > > > > report > > > > > > > > > > from > > > > > > > > > > >> > > Giannis > > > > > > > > > > >> > > > > > > Polyzos > > > > > > > > > > >> > > > > > > > > for > > > > > > > > > > >> > > > > > > > > > >> this > > > > > > > > > > >> > > > > > > > > > >> > > > >> usage: > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > https://lists.apache.org/thread/qljwd40v5ntz6733cwcdr8s4z97b343b > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > Aitozi < > > > > > > > gjying1...@gmail.com> > > > > > > > > > > >> > > > 于2023年5月23日周二 > > > > > > > > > > >> > > > > > > > 17:45写道： > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > Hi guys, > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > I want to > > > bring > > > > > up a > > > > > > > > > > >> discussion > > > > > > > > > > >> > > about > > > > > > > > > > >> > > > > > > adding > > > > > > > > > > >> > > > > > > > > > >> support > > > > > > > > > > >> > > > > > > > > > >> > of > > > > > > > > > > >> > > > > > > > > > >> > > > User > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > Defined > > > > > > AsyncTableFunction > > > > > > > > in > > > > > > > > > > >> Flink. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > Currently, > async > > > > table > > > > > > > > > function > > > > > > > > > > >> are > > > > > > > > > > >> > > > special > > > > > > > > > > >> > > > > > > > > functions > > > > > > > > > > >> > > > > > > > > > >> for > > > > > > > > > > >> > > > > > > > > > >> > > > table > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > source > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > to perform > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > async lookup. > > > > However, > > > > > > > it's > > > > > > > > > > worth > > > > > > > > > > >> to > > > > > > > > > > >> > > > > support > > > > > > > > > > >> > > > > > > the > > > > > > > > > > >> > > > > > > > > user > > > > > > > > > > >> > > > > > > > > > >> > > defined > > > > > > > > > > >> > > > > > > > > > >> > > > >> async > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > table > function. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > Because, in > this > > > > way, > > > > > > the > > > > > > > > end > > > > > > > > > > SQL > > > > > > > > > > >> > user > > > > > > > > > > >> > > > can > > > > > > > > > > >> > > > > > > > leverage > > > > > > > > > > >> > > > > > > > > > it > > > > > > > > > > >> > > > > > > > > > >> to > > > > > > > > > > >> > > > > > > > > > >> > > > >> perform > > > > > > > > > > >> > > > > > > > > > >> > > > >> > the > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > async > operation > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > which is > useful > > to > > > > > > maximum > > > > > > > > the > > > > > > > > > > >> system > > > > > > > > > > >> > > > > > > throughput > > > > > > > > > > >> > > > > > > > > > >> > especially > > > > > > > > > > >> > > > > > > > > > >> > > > for > > > > > > > > > > >> > > > > > > > > > >> > > > >> IO > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > bottleneck > case. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > You can find > > some > > > > more > > > > > > > > detail > > > > > > > > > in > > > > > > > > > > >> [1]. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > Looking > forward > > to > > > > > > > feedback > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > [1]: > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/FLINK/%5BFLIP-313%5D+Add+support+of+User+Defined+AsyncTableFunction > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > Thanks, > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > Aitozi. > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
