+1 for Matei's as well. On Sun, 22 Sep 2019, 14:59 Marco Gaido, <marcogaid...@gmail.com> wrote:
> I agree with Matei too. > > Thanks, > Marco > > Il giorno dom 22 set 2019 alle ore 03:44 Dongjoon Hyun < > dongjoon.h...@gmail.com> ha scritto: > >> +1 for Matei's suggestion! >> >> Bests, >> Dongjoon. >> >> On Sat, Sep 21, 2019 at 5:44 PM Matei Zaharia <matei.zaha...@gmail.com> >> wrote: >> >>> If the goal is to get people to try the DSv2 API and build DSv2 data >>> sources, can we recommend the 3.0-preview release for this? That would get >>> people shifting to 3.0 faster, which is probably better overall compared to >>> maintaining two major versions. There’s not that much else changing in 3.0 >>> if you already want to update your Java version. >>> >>> On Sep 21, 2019, at 2:45 PM, Ryan Blue <rb...@netflix.com.INVALID> >>> wrote: >>> >>> > If you insist we shouldn't change the unstable temporary API in 3.x . >>> . . >>> >>> Not what I'm saying at all. I said we should carefully consider whether >>> a breaking change is the right decision in the 3.x line. >>> >>> All I'm suggesting is that we can make a 2.5 release with the feature >>> and an API that is the same as the one in 3.0. >>> >>> > I also don't get this backporting a giant feature to 2.x line >>> >>> I am planning to do this so we can use DSv2 before 3.0 is released. Then >>> we can have a source implementation that works in both 2.x and 3.0 to make >>> the transition easier. Since I'm already doing the work, I'm offering to >>> share it with the community. >>> >>> >>> On Sat, Sep 21, 2019 at 2:36 PM Reynold Xin <r...@databricks.com> wrote: >>> >>>> Because for example we'd need to move the location of InternalRow, >>>> breaking the package name. If you insist we shouldn't change the unstable >>>> temporary API in 3.x to maintain compatibility with 3.0, which is totally >>>> different from my understanding of the situation when you exposed it, then >>>> I'd say we should gate 3.0 on having a stable row interface. >>>> >>>> I also don't get this backporting a giant feature to 2.x line ... as >>>> suggested by others in the thread, DSv2 would be one of the main reasons >>>> people upgrade to 3.0. What's so special about DSv2 that we are doing this? >>>> Why not abandoning 3.0 entirely and backport all the features to 2.x? >>>> >>>> >>>> >>>> On Sat, Sep 21, 2019 at 2:31 PM, Ryan Blue <rb...@netflix.com> wrote: >>>> >>>>> Why would that require an incompatible change? >>>>> >>>>> We *could* make an incompatible change and remove support for >>>>> InternalRow, but I think we would want to carefully consider whether that >>>>> is the right decision. And in any case, we would be able to keep 2.5 and >>>>> 3.0 compatible, which is the main goal. >>>>> >>>>> On Sat, Sep 21, 2019 at 2:28 PM Reynold Xin <r...@databricks.com> >>>>> wrote: >>>>> >>>>> How would you not make incompatible changes in 3.x? As discussed the >>>>> InternalRow API is not stable and needs to change. >>>>> >>>>> On Sat, Sep 21, 2019 at 2:27 PM Ryan Blue <rb...@netflix.com> wrote: >>>>> >>>>> > Making downstream to diverge their implementation heavily between >>>>> minor versions (say, 2.4 vs 2.5) wouldn't be a good experience >>>>> >>>>> You're right that the API has been evolving in the 2.x line. But, it >>>>> is now reasonably stable with respect to the current feature set and we >>>>> should not need to break compatibility in the 3.x line. Because we have >>>>> reached our goals for the 3.0 release, we can backport at least those >>>>> features to 2.x and confidently have an API that works in both a 2.x >>>>> release and is compatible with 3.0, if not 3.1 and later releases as well. >>>>> >>>>> > I'd rather say preparation of Spark 2.5 should be started after >>>>> Spark 3.0 is officially released >>>>> >>>>> The reason I'm suggesting this is that I'm already going to do the >>>>> work to backport the 3.0 release features to 2.4. I've been asked by >>>>> several people when DSv2 will be released, so I know there is a lot of >>>>> interest in making this available sooner than 3.0. If I'm already doing >>>>> the >>>>> work, then I'd be happy to share that with the community. >>>>> >>>>> I don't see why 2.5 and 3.0 are mutually exclusive. We can work on 2.5 >>>>> while preparing the 3.0 preview and fixing bugs. For DSv2, the work is >>>>> about complete so we can easily release the same set of features and API >>>>> in >>>>> 2.5 and 3.0. >>>>> >>>>> If we decide for some reason to wait until after 3.0 is released, I >>>>> don't know that there is much value in a 2.5. The purpose is to be a step >>>>> toward 3.0, and releasing that step after 3.0 doesn't seem helpful to me. >>>>> It also wouldn't get these features out any sooner than 3.0, as a 2.5 >>>>> release probably would, given the work needed to validate the incompatible >>>>> changes in 3.0. >>>>> >>>>> > DSv2 change would be the major backward incompatibility which Spark >>>>> 2.x users may hesitate to upgrade >>>>> >>>>> As I pointed out, DSv2 has been changing in the 2.x line, so this is >>>>> expected. I don't think it will need incompatible changes in the 3.x line. >>>>> >>>>> On Fri, Sep 20, 2019 at 9:25 PM Jungtaek Lim <kabh...@gmail.com> >>>>> wrote: >>>>> >>>>> Just 2 cents, I haven't tracked the change of DSv2 (though I needed to >>>>> deal with this as the change made confusion on my PRs...), but my bet is >>>>> that DSv2 would be already changed in incompatible way, at least who works >>>>> for custom DataSource. Making downstream to diverge their implementation >>>>> heavily between minor versions (say, 2.4 vs 2.5) wouldn't be a good >>>>> experience - especially we are not completely closed the chance to further >>>>> modify DSv2, and the change could be backward incompatible. >>>>> >>>>> If we really want to bring the DSv2 change to 2.x version line to let >>>>> end users avoid forcing to upgrade Spark 3.x to enjoy new DSv2, I'd rather >>>>> say preparation of Spark 2.5 should be started after Spark 3.0 is >>>>> officially released, honestly even later than that, say, getting some >>>>> reports from Spark 3.0 about DSv2 so that we feel DSv2 is OK. I hope we >>>>> don't make Spark 2.5 be a kind of "tech-preview" which Spark 2.4 users may >>>>> be frustrated to upgrade to next minor version. >>>>> >>>>> Btw, do we have any specific target users for this? Personally DSv2 >>>>> change would be the major backward incompatibility which Spark 2.x users >>>>> may hesitate to upgrade, so they might be already prepared to migrate to >>>>> Spark 3.0 if they are prepared to migrate to new DSv2. >>>>> >>>>> On Sat, Sep 21, 2019 at 12:46 PM Dongjoon Hyun < >>>>> dongjoon.h...@gmail.com> wrote: >>>>> >>>>> Do you mean you want to have a breaking API change between 3.0 and 3.1? >>>>> I believe we follow Semantic Versioning ( >>>>> https://spark.apache.org/versioning-policy.html ). >>>>> >>>>> > We just won’t add any breaking changes before 3.1. >>>>> >>>>> Bests, >>>>> Dongjoon. >>>>> >>>>> >>>>> On Fri, Sep 20, 2019 at 11:48 AM Ryan Blue <rb...@netflix.com.invalid> >>>>> wrote: >>>>> >>>>> I don’t think we need to gate a 3.0 release on making a more stable >>>>> version of InternalRow >>>>> >>>>> Sounds like we agree, then. We will use it for 3.0, but there are >>>>> known problems with it. >>>>> >>>>> Thinking we’d have dsv2 working in both 3.x (which will change and >>>>> progress towards more stable, but will have to break certain APIs) and 2.x >>>>> seems like a false premise. >>>>> >>>>> Why do you think we will need to break certain APIs before 3.0? >>>>> >>>>> I’m only suggesting that we release the same support in a 2.5 release >>>>> that we do in 3.0. Since we are nearly finished with the 3.0 goals, it >>>>> seems like we can certainly do that. We just won’t add any breaking >>>>> changes >>>>> before 3.1. >>>>> >>>>> On Fri, Sep 20, 2019 at 11:39 AM Reynold Xin <r...@databricks.com> >>>>> wrote: >>>>> >>>>> I don't think we need to gate a 3.0 release on making a more stable >>>>> version of InternalRow, but thinking we'd have dsv2 working in both 3.x >>>>> (which will change and progress towards more stable, but will have to >>>>> break >>>>> certain APIs) and 2.x seems like a false premise. >>>>> >>>>> To point out some problems with InternalRow that you think are already >>>>> pragmatic and stable: >>>>> >>>>> The class is in catalyst, which states: >>>>> https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/package.scala >>>>> >>>>> /** >>>>> * Catalyst is a library for manipulating relational query plans. All >>>>> classes in catalyst are >>>>> * considered an internal API to Spark SQL and are subject to change >>>>> between minor releases. >>>>> */ >>>>> >>>>> There is no even any annotation on the interface. >>>>> >>>>> The entire dependency chain were created to be private, and tightly >>>>> coupled with internal implementations. For example, >>>>> >>>>> >>>>> https://github.com/apache/spark/blob/master/common/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java >>>>> >>>>> /** >>>>> * A UTF-8 String for internal Spark use. >>>>> * <p> >>>>> * A String encoded in UTF-8 as an Array[Byte], which can be used for >>>>> comparison, >>>>> * search, see http://en.wikipedia.org/wiki/UTF-8 for details. >>>>> * <p> >>>>> * Note: This is not designed for general use cases, should not be used >>>>> outside SQL. >>>>> */ >>>>> >>>>> >>>>> >>>>> https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/ArrayData.scala >>>>> >>>>> (which again is in catalyst package) >>>>> >>>>> >>>>> If you want to argue this way, you might as well argue we should make >>>>> the entire catalyst package public to be pragmatic and not allow any >>>>> changes. >>>>> >>>>> >>>>> >>>>> >>>>> On Fri, Sep 20, 2019 at 11:32 AM, Ryan Blue <rb...@netflix.com> wrote: >>>>> >>>>> When you created the PR to make InternalRow public >>>>> >>>>> This isn’t quite accurate. The change I made was to use InternalRow >>>>> instead of UnsafeRow, which is a specific implementation of >>>>> InternalRow. Exposing this API has always been a part of DSv2 and >>>>> while both you and I did some work to avoid this, we are still in the >>>>> phase >>>>> of starting with that API. >>>>> >>>>> Note that any change to InternalRow would be very costly to implement >>>>> because this interface is widely used. That is why I think we can >>>>> certainly >>>>> consider it stable enough to use here, and that’s probably why >>>>> UnsafeRow was part of the original proposal. >>>>> >>>>> In any case, the goal for 3.0 was not to replace the use of >>>>> InternalRow, it was to get the majority of SQL working on top of the >>>>> interface added after 2.4. That’s done and stable, so I think a 2.5 >>>>> release >>>>> with it is also reasonable. >>>>> >>>>> On Fri, Sep 20, 2019 at 11:23 AM Reynold Xin <r...@databricks.com> >>>>> wrote: >>>>> >>>>> To push back, while I agree we should not drastically change >>>>> "InternalRow", there are a lot of changes that need to happen to make it >>>>> stable. For example, none of the publicly exposed interfaces should be in >>>>> the Catalyst package or the unsafe package. External implementations >>>>> should >>>>> be decoupled from the internal implementations, with cheap ways to convert >>>>> back and forth. >>>>> >>>>> When you created the PR to make InternalRow public, the understanding >>>>> was to work towards making it stable in the future, assuming we will start >>>>> with an unstable API temporarily. You can't just make a bunch internal >>>>> APIs >>>>> tightly coupled with other internal pieces public and stable and call it a >>>>> day, just because it happen to satisfy some use cases temporarily assuming >>>>> the rest of Spark doesn't change. >>>>> >>>>> >>>>> >>>>> On Fri, Sep 20, 2019 at 11:19 AM, Ryan Blue <rb...@netflix.com> wrote: >>>>> >>>>> > DSv2 is far from stable right? >>>>> >>>>> No, I think it is reasonably stable and very close to being ready for >>>>> a release. >>>>> >>>>> > All the actual data types are unstable and you guys have completely >>>>> ignored that. >>>>> >>>>> I think what you're referring to is the use of `InternalRow`. That's a >>>>> stable API and there has been no work to avoid using it. In any case, I >>>>> don't think that anyone is suggesting that we delay 3.0 until a >>>>> replacement >>>>> for `InternalRow` is added, right? >>>>> >>>>> While I understand the motivation for a better solution here, I think >>>>> the pragmatic solution is to continue using `InternalRow`. >>>>> >>>>> > If the goal is to make DSv2 work across 3.x and 2.x, that seems too >>>>> invasive of a change to backport once you consider the parts needed to >>>>> make >>>>> dsv2 stable. >>>>> >>>>> I believe that those of us working on DSv2 are confident about the >>>>> current stability. We set goals for what to get into the 3.0 release >>>>> months >>>>> ago and have very nearly reached the point where we are ready for that >>>>> release. >>>>> >>>>> I don't think instability would be a problem in maintaining >>>>> compatibility between the 2.5 version and the 3.0 version. If we find that >>>>> we need to make API changes (other than additions) then we can make those >>>>> in the 3.1 release. Because the goals we set for the 3.0 release have been >>>>> reached with the current API and if we are ready to release 3.0, we can >>>>> release a 2.5 with the same API. >>>>> >>>>> On Fri, Sep 20, 2019 at 11:05 AM Reynold Xin <r...@databricks.com> >>>>> wrote: >>>>> >>>>> DSv2 is far from stable right? All the actual data types are unstable >>>>> and you guys have completely ignored that. We'd need to work on that and >>>>> that will be a breaking change. If the goal is to make DSv2 work across >>>>> 3.x >>>>> and 2.x, that seems too invasive of a change to backport once you consider >>>>> the parts needed to make dsv2 stable. >>>>> >>>>> >>>>> >>>>> On Fri, Sep 20, 2019 at 10:47 AM, Ryan Blue <rb...@netflix.com.invalid >>>>> > wrote: >>>>> >>>>> Hi everyone, >>>>> >>>>> In the DSv2 sync this week, we talked about a possible Spark 2.5 >>>>> release based on the latest Spark 2.4, but with DSv2 and Java 11 support >>>>> added. >>>>> >>>>> A Spark 2.5 release with these two additions will help people migrate >>>>> to Spark 3.0 when it is released because they will be able to use a single >>>>> implementation for DSv2 sources that works in both 2.5 and 3.0. Similarly, >>>>> upgrading to 3.0 won't also require also updating to Java 11 because users >>>>> could update to Java 11 with the 2.5 release and have fewer major changes. >>>>> >>>>> Another reason to consider a 2.5 release is that many people are >>>>> interested in a release with the latest DSv2 API and support for DSv2 SQL. >>>>> I'm already going to be backporting DSv2 support to the Spark 2.4 line, so >>>>> it makes sense to share this work with the community. >>>>> >>>>> This release line would just consist of backports like DSv2 and Java >>>>> 11 that assist compatibility, to keep the scope of the release small. The >>>>> purpose is to assist people moving to 3.0 and not distract from the 3.0 >>>>> release. >>>>> >>>>> Would a Spark 2.5 release help anyone else? Are there any concerns >>>>> about this plan? >>>>> >>>>> >>>>> rb >>>>> >>>>> >>>>> -- >>>>> Ryan Blue >>>>> Software Engineer >>>>> Netflix >>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Ryan Blue >>>>> Software Engineer >>>>> Netflix >>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Ryan Blue >>>>> Software Engineer >>>>> Netflix >>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Ryan Blue >>>>> Software Engineer >>>>> Netflix >>>>> >>>>> >>>>> >>>>> -- >>>>> Name : Jungtaek Lim >>>>> Blog : http://medium.com/@heartsavior >>>>> Twitter : http://twitter.com/heartsavior >>>>> LinkedIn : http://www.linkedin.com/in/heartsavior >>>>> >>>>> >>>>> >>>>> -- >>>>> Ryan Blue >>>>> Software Engineer >>>>> Netflix >>>>> >>>>> >>>>> >>>>> -- >>>>> Ryan Blue >>>>> Software Engineer >>>>> Netflix >>>>> >>>> >>>> >>> >>> -- >>> Ryan Blue >>> Software Engineer >>> Netflix >>> >>> >>>
