You use kryo encoder for the whole thing? Or just the subtree that we don't have specific encoders for?
Also, I'm saying I like the idea of having a kryo fallback. I don't see the point of narrowing the the definition of the implicit. On Wed, Oct 26, 2016 at 1:07 PM, Koert Kuipers <ko...@tresata.com> wrote: > for example (the log shows when it creates a kryo encoder): > > scala> implicitly[EncoderEvidence[Option[Seq[String]]]].encoder > res5: org.apache.spark.sql.Encoder[Option[Seq[String]]] = class[value[0]: > array<string>] > > scala> implicitly[EncoderEvidence[Option[Set[String]]]].encoder > dataframe.EncoderEvidence$: using kryo encoder for > scala.Option[Set[String]] > res6: org.apache.spark.sql.Encoder[Option[Set[String]]] = class[value[0]: > binary] > > > > > On Wed, Oct 26, 2016 at 4:00 PM, Koert Kuipers <ko...@tresata.com> wrote: > >> why would generating implicits for ProductN where you also require the >> elements in the Product to have an expression encoder not work? >> >> we do this. and then we have a generic fallback where it produces a kryo >> encoder. >> >> for us the result is that say an implicit for Seq[(Int, Seq[(String, >> Int)])] will create a new ExpressionEncoder(), while an implicit for >> Seq[(Int, Set[(String, Int)])] produces a Encoders.kryoEncoder() >> >> On Wed, Oct 26, 2016 at 3:50 PM, Michael Armbrust <mich...@databricks.com >> > wrote: >> >>> Sorry, I realize that set is only one example here, but I don't think >>> that making the type of the implicit more narrow to include only ProductN >>> or something eliminates the issue. Even with that change, we will fail to >>> generate an encoder with the same error if you, for example, have a field >>> of your case class that is an unsupported type. >>> >>> Short of changing this to compile-time macros, I think we are stuck with >>> this class of errors at runtime. The simplest solution seems to be to >>> expand the set of thing we can handle as much as possible and allow users >>> to turn on a kryo fallback for expression encoders. I'd be hesitant to >>> make this the default though, as behavior would change with each release >>> that adds support for more types. I would be very supportive of making >>> this fallback a built-in option though. >>> >>> On Wed, Oct 26, 2016 at 11:47 AM, Koert Kuipers <ko...@tresata.com> >>> wrote: >>> >>>> yup, it doesnt really solve the underlying issue. >>>> >>>> we fixed it internally by having our own typeclass that produces >>>> encoders and that does check the contents of the products, but we did this >>>> by simply supporting Tuple1 - Tuple22 and Option explicitly, and not >>>> supporting Product, since we dont have a need for case classes >>>> >>>> if case classes extended ProductN (which they will i think in scala >>>> 2.12?) then we could drop Product and support Product1 - Product22 and >>>> Option explicitly while checking the classes they contain. that would be >>>> the cleanest. >>>> >>>> >>>> On Wed, Oct 26, 2016 at 2:33 PM, Ryan Blue <rb...@netflix.com> wrote: >>>> >>>>> Isn't the problem that Option is a Product and the class it contains >>>>> isn't checked? Adding support for Set fixes the example, but the problem >>>>> would happen with any class there isn't an encoder for, right? >>>>> >>>>> On Wed, Oct 26, 2016 at 11:18 AM, Michael Armbrust < >>>>> mich...@databricks.com> wrote: >>>>> >>>>>> Hmm, that is unfortunate. Maybe the best solution is to add support >>>>>> for sets? I don't think that would be super hard. >>>>>> >>>>>> On Tue, Oct 25, 2016 at 8:52 PM, Koert Kuipers <ko...@tresata.com> >>>>>> wrote: >>>>>> >>>>>>> i am trying to use encoders as a typeclass where if it fails to find >>>>>>> an ExpressionEncoder it falls back to KryoEncoder. >>>>>>> >>>>>>> the issue seems to be that ExpressionEncoder claims a little more >>>>>>> than it can handle here: >>>>>>> implicit def newProductEncoder[T <: Product : TypeTag]: Encoder[T] >>>>>>> = Encoders.product[T] >>>>>>> >>>>>>> this "claims" to handle for example Option[Set[Int]], but it really >>>>>>> cannot handle Set so it leads to a runtime exception. >>>>>>> >>>>>>> would it be useful to make this a little more specific? i guess the >>>>>>> challenge is going to be case classes which unfortunately dont extend >>>>>>> Product1, Product2, etc. >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> Ryan Blue >>>>> Software Engineer >>>>> Netflix >>>>> >>>> >>>> >>> >> >
