Hey Bruno thanks for the feedback. 1) I will add this to the kip, but stream time only advances as the when the buffer receives a new record.
2) You are correct, I will add a failure section on to the kip. Since the records wont change in the buffer from when they are read from the topic they are replicated already. 3) I see that I'm out voted on the dropping of records thing. We will pass them on and try to join them if possible. This might cause some null results, but increasing the table history retention should help that. 4) I can add some on the kip. But its pretty directly adding whatever the grace period is to the latency. I don't see a way around it. Walker On Thu, Jun 1, 2023 at 5:23 AM Bruno Cadonna <cado...@apache.org> wrote: > Hi Walker, > > thanks for the KIP! > > Here my feedback: > > 1. > It is still not clear to me when stream time for the buffer advances. > What is the event that let the stream time advance? In the discussion, I > do not understand what you mean by "The segment store already has an > observed stream time, we advance based on that. That should only advance > based on records that enter the store." Where does this segment store > come from? Anyways, I think it would be great to also state how stream > time advances in the KIP. > > 2. > How does the buffer behave in case of a failure? I think I understand > that the buffer will use an implementation of TimeOrderedKeyValueBuffer > and therefore the records in the buffer will be replicated to a topic in > Kafka, but I am not completely sure. Could you elaborate on this in the > KIP? > > 3. > I agree with Matthias about dropping late records. We use grace periods > in scenarios where we records are grouped like in windowed aggregations > and windowed joins. The stream buffer you propose does not really group > any records. It rather delays records and reorders them. I am not sure > if grace period is the right naming/concept to apply here. Instead of > dropping records that fall outside of the buffer's time interval the > join should skip the buffer and try to join the record immediately. In > the end, a stream-table join is a unwindowed join, i.e., no grouping is > applied to the records. > What do you and other folks think about this proposal? > > 4. > How does the proposed buffer, affects processing latency? Could you > please add some words about this to the KIP? > > > Best, > Bruno > > > > > On 31.05.23 01:49, Walker Carlson wrote: > > Thanks for all the additional comments. I will either address them here > or > > update the kip accordingly. > > > > > > I mentioned a follow kip to add extra features before and in the > responses. > > I will try to briefly summarize what options and optimizations I plan to > > include. If a concern is not covered in this list I for sure talk about > it > > below. > > > > * Allowing non versioned tables to still use the stream buffer > > * Automatically materializing tables instead of forcing the user to do it > > * Configurable for in memory buffer > > * Order the records in offset order or in time order > > * Non memory use buffer (offset order, delayed pull from stream.) > > * Time synced between stream and table side (maybe) > > * Do not drop late records and process them as they come in instead. > > > > > > First, Victoria. > > > > 1) (One of your nits covers this, but you are correct it doesn't make > > sense. so I removed that part of the example.) > > For those examples with the "bad" join results I said without buffering > the > > stream it would look like that, but that was incomplete. If the look up > was > > simply looking at the latest version of the table when the stream records > > came in then the results were possible. If we are using the point in time > > lookup that versioned tables let us then you are correct the future > results > > are not possible. > > > > 2) I'll get to this later as Matthias brought up something related. > > > > To your additional thoughts, I agree that we need to call those things > out > > in the documentation. I'm writing up a follow up kip with a lot of the > > ideas we have discussed so that we can improve this feature beyond the > base > > implementation if it's needed. > > > > I addressed the nits in the kip. I somehow missed the table stream table > > join processor improvement, it makes your first question make a lot more > > sense. Table history retention is a much cleaner way to describe it. > > > > As to your mention of the syncing the time for the table and stream. > > Matthias mentioned that as well. I will address both here. I plan to > bring > > that up in the future, but for now we will leave it out. I suppose it > will > > be more useful after the table history retention is separable from the > > table grace period. > > > > > > To address Matthias comments. > > > > You are correct by saying the in memory store shouldn't cause any > semantic > > concerns. My concern would be more with if we limited the number of > records > > on the buffer and what we would do if we hit said limits, (emitting those > > records might be an issue, throwing an error and halting would not). I > > think we can leave this discussion to the follow up kip along with a few > > other options. > > > > I will go through your proposals now. > > > > - don't support non-versioned KTables > > > > Sure, we can always expand this later on. Will include as part of the of > > the improvement kip > > > > - if grace period is added, users need to explicitly materialize the > > table as version (either directly, or upstream. Upstream only works if > > downstream tables "inherit" versioned semantics -- cf KIP-914) > > > > again, that works for me for now, if we find a use we can always add > later. > > > > - the table's history retention time must be larger than the grace > > period (should be easy to check at runtime, when we build the topology) > > > > agreed > > > > - because switching from non-versioned to version stores is not > > backward compatibly (cf KIP-914), users need to take care of this > > themselves, and this also implies that adding grace period is not a > > backward compatible change (even only if via indirect means) > > > > sure, this works > > > > As to the dropping of late records, I'm not sure. One one hand I like not > > dropping things. But on the other I struggle to see how a user can filter > > out late records that might have incomplete join results. The point in > time > > look up will aggressively expire old data and if new data has been > replaced > > it will return null if outside of the retention. This seems like it could > > corrupt the integrity of the join output. Seeing that we drop late > records > > on the table side as well I would think it makes sense to drop late > records > > on the stream buffer. I could be convinced otherwise I suppose, I could > see > > adding this as an option in a follow up kip. It would be very easy to > > implement either way. For now unless no one else objects I'm going to > stick > > with dropping the records for the sake of getting this kip passed. It is > > functionally a small change to make and we can update later if you feel > > strongly about it. > > > > For the ordering. I have to say that it would be more complicated to > > implement it to be in offset order, if the goal it to get as many of the > > records validly joined as possible. Because we would process as things > left > > the buffer a sufficiency early enough record could hold up records that > > would otherwise be valid past the table history retention. To fix this we > > could process by timestamp then store in a second queue and emit by > offset, > > but that would be a lot more complicated. If we didn't care about not > > missing some valid joins we could just have no store and pull from the > > topic at a delay only caring about the timestamp of the next offset. For > > now I want to stick with the timestamp ordering as it makes much more > sense > > to me, but would propose we add both of the other options I have laid out > > here in the follow up kip. > > > > Lastly, I think having an empty store with zero grace period would be > super > > simple and not costly, so we might as well make it even if nothing gets > > entered. > > > > I hope that address all your concerns, > > > > Walker > > > > On Thu, May 25, 2023 at 9:50 AM Matthias J. Sax <mj...@apache.org> > wrote: > > > >> Walker, > >> > >> thanks for the updates. The KIP itself reads fine (of course Victoria > >> made good comments about some phrases), but there is a couple of things > >> from your latest reply I don't understand, and that I still think need > >> some more discussions. > >> > >> Lukas, asked about in-memory option and `WindowStoreSupplier` and you > >> mention "semantic concerns". There should not be any semantic difference > >> from the underlying buffer implementation, so I am not sure what you > >> mean here (also the relationship to suppress() is unclear to me)? -- I > >> am ok to not make it configurable for now. We can always do it via a > >> follow up KIP, and keep interface changes limited for now. > >> > >> Does it really make sense to allow a grace period if the table is > >> non-versioned? You also say: "If table is not materialized it will > >> materialize it as versioned." -- What history retention time would we > >> pick for this case (also asked by Victoria)? Or should we rather not > >> support this and force the user to materialize the table explicitly, and > >> thus explicitly picking a history retention time? It's tradeoff between > >> usability and guiding uses that there will be a significant impact on > >> disk usage. There is also compatibility concerns: If the table is not > >> explicitly materialized in the old program, we would already need to > >> materialize it also in the old program (of course, we would use a > >> non-versioned store so far). Thus, if somebody adds a grace period, we > >> cannot just switch the store type, as it would be a breaking change, > >> potentially required an application re-set, or following the upgrade > >> path for versioned state stores, and also changing the program to > >> explicitly materialize using a versioned store. Also note, that we might > >> not materialize the actual join table, but only an upstream table, and > >> use `ValueGetter` to access the upstream data. > >> > >> To this end, as you already mentioned, history retention of the table > >> should be at least grace period. You proposed to include this in a > >> follow up KIP, but I am wondering if it's a fundamental requirement and > >> thus we should put a check in place right away and reject an invalid > >> configuration? (It always easier to lift restriction than to introduce > >> them later.) This would also imply that a non-versioned table cannot be > >> supported, because it does not have a history retention that is larger > >> than grace period, and maybe also answer the requirement about > >> materialization: as we already always materialize something on the > >> tablet side as non-versioned store right now, it seems difficult to > >> migrate the store to a versioned store. Ie, it might be ok to push the > >> burden onto the user and say: if you start using grace period, you also > >> need to manually switch from non-versioned to versioned KTables. Doing > >> stuff automatically under the hood if very complex for this case, we if > >> we push the burden onto the user, it might be ok to not complicate this > >> KIP significantly. > >> > >> To summarize the last two paragraphs, I would propose to: > >> - don't support non-versioned KTables > >> - if grace period is added, users need to explicitly materialize the > >> table as version (either directly, or upstream. Upstream only works if > >> downstream tables "inherit" versioned semantics -- cf KIP-914) > >> - the table's history retention time must be larger than the grace > >> period (should be easy to check at runtime, when we build the topology) > >> - because switching from non-versioned to version stores is not > >> backward compatibly (cf KIP-914), users need to take care of this > >> themselves, and this also implies that adding grace period is not a > >> backward compatible change (even only if via indirect means) > >> > >> About dropping late records: wondering if we should never drop a > >> stream-side record for a left-join, even if it's late? In general, one > >> thing I observed over the years is, that it's easier to keep stuff and > >> let users filter explicitly downstream (or make it configurable), > >> instead of dropping pro-actively, because users have no good way to > >> resurrect record that got already dropped. > >> > >> For ordering, sounds reasonable to me only start with one > >> implementation, and maybe make it configurable as a follow up. However, > >> I am wondering if starting with offset order might be the better option > >> as it seems to align more with what we do so far? So instead of storing > >> record ordered by timestamp, we can just store them ordered by offset, > >> and still "poll" from the buffer based on the head records timestamp. Or > >> would this complicate the implementation significantly? > >> > >> I also think it's ok to not "sync" stream-time between the table and the > >> stream in this KIP, but we should consider doing this as a follow up > >> change (not sure if we would need a KIP or not for a change this this). > >> > >> About increasing/decreasing grace period: what you describe make sense > >> to me. If decreased, the next record would just trigger emitting a lot > >> of records, and for increase, the buffer would just need to "fill up" > >> again. For reprocessing getting a different result with a different > >> grace period is expected, so that's ok IMHO. -- There seems to be one > >> special corner case: grace period zero. For this case, we actually don't > >> need any store, and the stream-side could be stateless. I think it can > >> have the same behavior, but if we want to "add / remove" the store > >> dynamically, we need to add specific code for it. For example, even if > >> we start up with a grace period of zero, we would need to check if there > >> is a local store, and still emit everything in it, before we can ditch > >> the store (not sure if that's even easily done at all). Or: we would > >> need to have a store for _all_ cases, even if grace period is zero (the > >> store would be empty all the time though), to avoid super complex code? > >> > >> > >> -Matthias > >> > >> > >> On 5/25/23 10:53 AM, Lucas Brutschy wrote: > >>> Hi Walker, > >>> > >>> thanks for your responses. That makes sense. I guess there is always > >>> the option to make the implementation more configurable later on, if > >>> users request it. Also thanks for the clarifications. From my side, > >>> the KIP is good to go. > >>> > >>> Cheers, > >>> Lucas > >>> > >>> On Wed, May 24, 2023 at 11:54 PM Victoria Xia > >>> <victoria....@confluent.io.invalid> wrote: > >>>> > >>>> Thanks for the updates, Walker! Looks great, though I do have a couple > >>>> questions about the latest updates: > >>>> > >>>> 1. The new example says that without stream-side buffering, "ex" > and > >>>> "fy" are possible join results. How could those join results > >> happen? The > >>>> example versioned table suggests that table record "x" has > >> timestamp 2, and > >>>> table record "y" has timestamp 3. If stream record "e" has > >> timestamp 1, > >>>> then it can never be joined against record "x", and similarly for > >> stream > >>>> record "f" with timestamp 2 being joined against "y". > >>>> 2. I see in your replies above that "If table is not > materialized it > >>>> will materialize it as versioned" but I don't see this called out > >> in the > >>>> KIP -- seems worth calling out. Also, what will the history > >> retention for > >>>> the versioned table be? Will it be the same as the join grace > >> period, or > >>>> will it be greater? > >>>> > >>>> > >>>> And some additional thoughts: > >>>> > >>>> Sounds like there are a few things users should watch out for when > >> enabling > >>>> the stream-side buffer: > >>>> > >>>> - Records will get "stuck" if there are no newer records to > advance > >>>> stream time. > >>>> - If there are large gaps between the timestamps of stream-side > >> records, > >>>> then it's possible that versioned store history retention will > have > >> expired > >>>> by the time a record is evicted from the join buffer, leading to > a > >> join > >>>> "miss." For example, if the join grace period and table history > >> retention > >>>> are both 10, and records come in the order: > >>>> > >>>> table side t0 with ts=0 > >>>> stream side s1 with ts=1 <-- enters buffer > >>>> table side t10 with ts=10 > >>>> table side t20 with ts=20 > >>>> stream side s21 with ts=21 <-- evicts record s1 from buffer, but > >>>> versioned store no longer contains data for ts=1 due to history > >> retention > >>>> having elapsed > >>>> > >>>> This will result in the join result (s1, null) even though it > >> should've > >>>> been (s1, t0), due to t0 having been expired from the versioned > >> store > >>>> already. > >>>> - Out-of-order records from the stream-side will be reordered, > and > >> late > >>>> records will be dropped. > >>>> > >>>> I don't think any of these are reasons to not go forward with this > KIP, > >> but > >>>> it'd be good to call them out in the eventual documentation to > decrease > >> the > >>>> chance users get tripped up. > >>>> > >>>>> We could maybe do an improvement later to advance stream time from > >> table > >>>> side as well, but that might be debatable as we might get more late > >> records. > >>>> > >>>> Yes, the likelihood of late records increases but also the likelihood > of > >>>> "join misses" due to versioned store history retention having elapsed > >>>> decreases, which feels important for certain use cases. Either way, > >> agreed > >>>> that it can be a discussion for the future as incorporating this would > >>>> substantially complicate the implementation. > >>>> > >>>> Also a couple nits: > >>>> > >>>> - The KIP currently says "We recently added versioned tables > which > >> allow > >>>> the table side of the a join [...] but it is not taken advantage > of > >> in > >>>> joins," but this doesn't seem true? If the table of a > stream-table > >> join is > >>>> versioned, then the DSL's stream-table join processor will > >> automatically > >>>> perform timestamped lookups into the table, in order to take > >> advantage of > >>>> the new timestamp-aware store to provide better join semantics. > >>>> - The KIP mentions "grace period" for versioned stores in a > number > >> of > >>>> places but I think you actually mean "history retention"? The two > >> happen to > >>>> be the same today (it is not an option for users to configure the > >> two > >>>> separately) but this need not be true in the future. "History > >> retention" > >>>> governs how far back in time reads may occur, which is the > relevant > >>>> parameter for performing lookups as part of the stream-table > join. > >> "Grace > >>>> period" in the context of versioned stores refers to how far back > >> in time > >>>> out-of-order writes may occur, which probably isn't directly > >> relevant for > >>>> introducing a stream-side buffer, though it's also possible I've > >> overlooked > >>>> something. (As a bonus, switching from "table grace period" in > the > >> KIP to > >>>> "table history retention" also helps to clarify/distinguish that > >> it's a > >>>> different parameter from the "join grace period," which I could > see > >> being > >>>> confusing to readers. :) ) > >>>> > >>>> > >>>> Cheers, > >>>> Victoria > >>>> > >>>> On Thu, May 18, 2023 at 1:43 PM Walker Carlson > >>>> <wcarl...@confluent.io.invalid> wrote: > >>>> > >>>>> Hey all, > >>>>> > >>>>> Thanks for the comments, they gave me a lot to think about. I'll try > to > >>>>> address them all inorder. I have made some updates to the kip related > >> to > >>>>> them, but I mention where below. > >>>>> > >>>>> Lucas > >>>>> > >>>>> Good idea about the example. I added a simple one. > >>>>> > >>>>> 1) I have thought about including options for the underlying buffer > >>>>> configuration. One of which might be adding an in memory option. My > >> biggest > >>>>> concern is about the semantic guarantees. This isn't like suppress or > >> with > >>>>> windows where producing incomplete results is repetitively harmless. > >> Here > >>>>> we would be possibly producing incorrect results. I also would like > to > >> keep > >>>>> the interface changes as simple as I can. Making more than this > change > >> to > >>>>> Joined I feel could make this more complicated than it needs to be. > If > >> we > >>>>> really want to I could see adding a grace() option with a > BufferConifg > >> in > >>>>> there or something, but I would rather not. > >>>>> > >>>>> 2) The buffer will be independent of if the table is versioned or > not. > >> If > >>>>> table is not materialized it will materialize it as versioned. It > might > >>>>> make sense to do a follow up kip where we force the retention period > >> of > >>>>> the versioned to be greater than whatever the max of the stream > buffer > >> is. > >>>>> > >>>>> Victoria > >>>>> > >>>>> 1) Yes, records will exit in timestamp order not in offset order. > >>>>> 2) Late records will be dropped (Late as out of the grace period). > >> From my > >>>>> understanding that is the point of a grace period, no? Doesn't the > same > >>>>> thing happen with versioned stores? > >>>>> 3) The segment store already has an observed stream time, we advance > >> based > >>>>> on that. That should only advance based on records that enter the > >> store. So > >>>>> yes, only stream side records. We could maybe do an improvement later > >> to > >>>>> advance stream time from table side as well, but that might be > >> debatable as > >>>>> we might get more late records. Anyways I would rather have that as a > >>>>> separate discussion. > >>>>> > >>>>> in memory option? We can do that, for the buffer I plan to use the > >>>>> TimeOrderedKeyValueBuffer interface which already has an in memory > >>>>> implantation, so it would be simple. > >>>>> > >>>>> I said more in my answer to Lucas's question. The concern I have with > >>>>> buffer configs or in memory is complicating the interface. Also > >> semantic > >>>>> guarantees but in memory shouldn't effect that > >>>>> > >>>>> Matthias > >>>>> > >>>>> 1) fixed out of order vs late terminology in the kip. > >>>>> > >>>>> 2) I was referring to having a stream. So after this kip we can have > a > >>>>> buffered stream or a normal one. For the table we can use a versioned > >> table > >>>>> or a normal table. > >>>>> > >>>>> 3 Good call out. I clarified this as "If the table side uses a > >> materialized > >>>>> version store, it can store multiple versions of each record within > its > >>>>> defined grace period." and modified the rest of the paragraph a bit. > >>>>> > >>>>> 4) I get the preserving off offset ordering, but if the stream is > >> buffered > >>>>> to join on timestamp instead of offset doesn't it already seem like > we > >> care > >>>>> more about time in this case? > >>>>> > >>>>> If we end up adding more options it might make sense to do this. > Maybe > >>>>> offset order processing can be a follow up? > >>>>> > >>>>> I'll add a section for this in Rejected Alternatives. I think it > makes > >>>>> sense to do something like this but maybe in a follow up. > >>>>> > >>>>> 5) I hadn't thought about this. I suppose if they changed this in an > >>>>> upgrade the next record would either evict a lot of records (if the > >> grace > >>>>> period decreased) or there would be a pause until the new grace > period > >>>>> reached. Increasing is a bit more problematic, especially if the > table > >>>>> grace period and retention time stays the same. If the data is > >> reprocessed > >>>>> after a change like that then there would be different results, but I > >> feel > >>>>> like that would be expected after such a change. > >>>>> > >>>>> What do you think should happen? > >>>>> > >>>>> Hopefully this answers your questions! > >>>>> > >>>>> Walker > >>>>> > >>>>> On Mon, May 8, 2023 at 11:32 AM Matthias J. Sax <mj...@apache.org> > >> wrote: > >>>>> > >>>>>> Thanks for the KIP! Also some question/comments from my side: > >>>>>> > >>>>>> 10) Notation: you use the term "late data" but I think you mean > >>>>>> out-of-order. We reserve the term "late" to records that arrive > after > >>>>>> grace period passed, and thus, "late == out-of-order data that is > >>>>> dropped". > >>>>>> > >>>>>> > >>>>>> 20) "There is only one option from the stream side and only recently > >> is > >>>>>> there a second option on the table side." > >>>>>> > >>>>>> What are those options? Victoria already asked about the table side, > >> but > >>>>>> I am also not sure what option you mean for the stream side? > >>>>>> > >>>>>> > >>>>>> 30) "If the table side uses a materialized version store the value > is > >>>>>> the latest by stream time rather than by offset within its defined > >> grace > >>>>>> period." > >>>>>> > >>>>>> The phrase "the value is the latest by stream time" is confusing -- > in > >>>>>> the end, a versioned stores multiple versions, not just one. > >>>>>> > >>>>>> > >>>>>> 40) I am also wondering about ordering. In general, KS tries to > >> preserve > >>>>>> offset-order during processing (with some exception, when offset > order > >>>>>> preservation is not clearly defined). Given that the stream-side > >> buffer > >>>>>> is really just a "linear buffer", we could easily preserve > >> offset-order. > >>>>>> But I also see a benefit of re-ordering and emitting out-of-order > data > >>>>>> right away when read (instead of blocking them behind in-order > records > >>>>>> that are not ready yet). -- It might even be a possibility, to let > >> users > >>>>>> pick a emit strategy eg "EmitStrategy.preserveOffsets" (name just a > >>>>>> placeholder). > >>>>>> > >>>>>> The KIP should explain this in more detail and also discuss > different > >>>>>> options and mention them in "Rejected alternatives" in case we don't > >>>>>> want to include them. > >>>>>> > >>>>>> > >>>>>> 50) What happens when users change the grace period? Especially, > when > >>>>>> they turn it on/off (but also increasing/decreasing is an > interesting > >>>>>> point)? I think we should try to support this if possible; the > >>>>>> "Compatibility" section needs to cover switching on/off in more > >> detail. > >>>>>> > >>>>>> > >>>>>> -Matthias > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> On 5/2/23 2:06 PM, Victoria Xia wrote: > >>>>>>> Cool KIP, Walker! Thanks for sharing this proposal. > >>>>>>> > >>>>>>> A few clarifications: > >>>>>>> > >>>>>>> 1. Is the order that records exit the buffer in necessarily the > same > >> as > >>>>>> the > >>>>>>> order that records enter the buffer in, or no? Based on the > >> description > >>>>>> in > >>>>>>> the KIP, it sounds like the answer is no, i.e., records will exit > the > >>>>>>> buffer in increasing timestamp order, which means that they may be > >>>>>> ordered > >>>>>>> (even for the same key) compared to the input order. > >>>>>>> > >>>>>>> 2. What happens if the join grace period is nonzero, and a > >> stream-side > >>>>>>> record arrives with a timestamp that is older than the current > stream > >>>>>> time > >>>>>>> minus the grace period? Will this record trigger a join result, or > >> will > >>>>>> it > >>>>>>> be dropped? Based on the description for what happens when the join > >>>>> grace > >>>>>>> period is set to zero, it sounds like the late record will be > >> dropped, > >>>>>> even > >>>>>>> if the join grace period is nonzero. Is that true? > >>>>>>> > >>>>>>> 3. What could cause stream time to advance, for purposes of > removing > >>>>>>> records from the join buffer? For example, will new records > arriving > >> on > >>>>>> the > >>>>>>> table side of the join cause stream time to advance? From the KIP > it > >>>>>> sounds > >>>>>>> like only stream-side records will advance stream time -- does that > >>>>> mean > >>>>>>> that the join processor itself will have to track this stream time? > >>>>>>> > >>>>>>> Also +1 to Lucas's question about what options will be available > for > >>>>>>> configuring the join buffer. Will users have the option to choose > >>>>> whether > >>>>>>> they want the buffer to be in-memory vs persistent? > >>>>>>> > >>>>>>> - Victoria > >>>>>>> > >>>>>>> On Fri, Apr 28, 2023 at 11:54 AM Lucas Brutschy > >>>>>>> <lbruts...@confluent.io.invalid> wrote: > >>>>>>> > >>>>>>>> HI Walker, > >>>>>>>> > >>>>>>>> thanks for the KIP! We definitely need this. I have two questions: > >>>>>>>> > >>>>>>>> - Have you considered allowing the customization of the > >> underlying > >>>>>>>> buffer implementation? As I can see, `StreamJoined` lets you > >> customize > >>>>>>>> the underlying store via a `WindowStoreSupplier`. Would it make > >> sense > >>>>>>>> for `Joined` to have this as well? I can imagine one may want to > >> limit > >>>>>>>> the number of records in the buffer, for example. If we hit the > >>>>>>>> maximum, the only option would be to drop semantic guarantees, but > >>>>>>>> users may still want to do this. > >>>>>>>> - With "second option on the table side" you are referring to > >>>>>>>> versioned tables, right? Will the buffer on the stream side behave > >> any > >>>>>>>> different whether the table side is versioned or not? > >>>>>>>> > >>>>>>>> Finally, I think a simple example in the motivation section could > >> help > >>>>>>>> non-experts understand the KIP. > >>>>>>>> > >>>>>>>> Best, > >>>>>>>> Lucas > >>>>>>>> > >>>>>>>> On Tue, Apr 25, 2023 at 9:13 PM Walker Carlson > >>>>>>>> <wcarl...@confluent.io.invalid> wrote: > >>>>>>>>> > >>>>>>>>> Hello everybody, > >>>>>>>>> > >>>>>>>>> I have a stream proposal to improve the stream table join by > >> adding a > >>>>>>>> grace > >>>>>>>>> period and buffer to the stream side of the join to allow > >> processing > >>>>> in > >>>>>>>>> timestamp order matching the recent improvements of the versioned > >>>>>> tables. > >>>>>>>>> > >>>>>>>>> Please take a look here < > >>>>> https://cwiki.apache.org/confluence/x/lAs0Dw> > >>>>>>>> and > >>>>>>>>> share your thoughts. > >>>>>>>>> > >>>>>>>>> best, > >>>>>>>>> Walker > >>>>>>>> > >>>>>>> > >>>>>> > >>>>> > >> > > >
