i use kryo for the whole thing currently it would be better to use it for the subtree
On Wed, Oct 26, 2016 at 5:06 PM, Michael Armbrust <mich...@databricks.com> wrote: > 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 >>>>>> >>>>> >>>>> >>>> >>> >> >
