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From Julian Hyde <jh...@apache.org>
Subject Re: Avatica's Meta.Frame appears to be unable to serialize float and char column values
Date Wed, 04 Nov 2020 21:35:21 GMT
Thanks for the clarification. Yes, open a PR.

Please don't assume that it will be me that reviews the PR.

Julian

On Wed, Nov 4, 2020 at 7:14 AM Dmitri Bourlatchkov
<dmitri.bourlatchkov@gmail.com> wrote:
>
> Hi Julian,
>
> Apologies for pinging directly. Does the information below answer your
> previous question about this or would you like me to go into more details?
>
> Does it sound worth a Jira ticket (and PR)?
>
> Thanks,
> Dmitri.
>
> On Fri, 30 Oct 2020 at 17:25, Dmitri Bourlatchkov <
> dmitri.bourlatchkov@gmail.com> wrote:
>
> > >  [...] I wanted to get a better idea what circumstances cause it.
> >
> > In this particular case I came across this failure while experimenting
> > with SQL support in Stargate [1], which uses Apache Cassandra for storage
> > and Cassandra's float type is actually 32-bit [2], so it naturally maps to
> > java float.
> >
> > In my use case data from storage is wired to Avatica's Frame objects via a
> > custom Meta implementation.
> >
> > [1] https://github.com/stargate/stargate
> > [2] https://cassandra.apache.org/doc/latest/cql/types.html
> >
> > On Fri, 30 Oct 2020 at 14:57, Dmitri Bourlatchkov <
> > dmitri.bourlatchkov@gmail.com> wrote:
> >
> >> Hello,
> >>
> >> I noticed that if the rows passed to
> >> org.apache.calcite.avatica.Meta.Frame contain Float values, the following
> >> exception [1] occurs when the frame is sent to the client with PROTOBUF
> >> serialization.
> >>
> >> Would this be considered a valid use case?
> >>
> >> I can only reproduce it in unit tests or with custom code using the
> >> Avatica server. If Avatica is corrected to a JDBC backend, it appears to
> >> always convert float values to Double and this failure mode does not
> >> manifest.
> >>
> >> A similar class cast problem occurs with char values.
> >>
> >> What do you think?
> >>
> >> If you think it is worth fixing, I should be able to submit a pull
> >> request quickly. I believe the fix is fairly small.
> >>
> >> Thanks,
> >> Dmitri.
> >>
> >> [1] Exception snippet:
> >> java.lang.ClassCastException: java.lang.Long cannot be cast to
> >> java.lang.Float
> >> at
> >> org.apache.calcite.avatica.remote.TypedValue.writeToProtoWithType(TypedValue.java:600)
> >> at
> >> org.apache.calcite.avatica.remote.TypedValue.toProto(TypedValue.java:805)
> >> at org.apache.calcite.avatica.Meta$Frame.serializeScalar(Meta.java:991)
> >> at org.apache.calcite.avatica.Meta$Frame.parseColumn(Meta.java:977)
> >> at org.apache.calcite.avatica.Meta$Frame.toProto(Meta.java:942)
> >> at
> >> org.apache.calcite.avatica.remote.Service$FetchResponse.serialize(Service.java:1468)
> >> [...snip...]
> >>
> >

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