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Posted to dev@calcite.apache.org by Dmitri Bourlatchkov <dm...@gmail.com> on 2020/11/04 15:14:11 UTC
Re: Avatica's Meta.Frame appears to be unable to serialize float and
char column values
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...]
>>
>
Re: Avatica's Meta.Frame appears to be unable to serialize float and
char column values
Posted by Julian Hyde <jh...@apache.org>.
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
<dm...@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...]
> >>
> >