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From Xiao Li <gatorsm...@gmail.com>
Subject Re: Why Apache Spark doesn't use Calcite?
Date Wed, 15 Jan 2020 17:39:27 GMT
In the upcoming Spark 3.0, we introduced a new framework for Adaptive Query
Execution in Catalyst. This can adjust the plans based on the runtime
statistics. This is missing in Calcite based on my understanding.

Catalyst is also very easy to enhance. We also use the dynamic programming
approach in our cost-based join reordering. If needed, in the future, we
also can improve the existing CBO and make it more general. The paper of
Spark SQL was published 5 years ago. A lot of great contributions were made
in the past 5 years.

Cheers,

Xiao

Debajyoti Roy <newroyker@gmail.com> 于2020年1月15日周三 上午9:23写道:

> Thanks all, and Matei.
>
> TL;DR of the conclusion for my particular case:
> Qualitatively, while Catalyst[1] tries to mitigate learning curve and
> maintenance burden, it lacks the dynamic programming approach used by
> Calcite[2] and risks falling into local minima.
> Quantitatively, there is no reproducible benchmark, that fairly compares
> Optimizer frameworks, apples to apples (excluding execution).
>
> References:
> [1] -
> https://amplab.cs.berkeley.edu/wp-content/uploads/2015/03/SparkSQLSigmod2015.pdf
> [2] - https://arxiv.org/pdf/1802.10233.pdf
>
> On Mon, Jan 13, 2020 at 5:37 PM Matei Zaharia <matei.zaharia@gmail.com>
> wrote:
>
>> I’m pretty sure that Catalyst was built before Calcite, or at least in
>> parallel. Calcite 1.0 was only released in 2015. From a technical
>> standpoint, building Catalyst in Scala also made it more concise and easier
>> to extend than an optimizer written in Java (you can find various
>> presentations about how Catalyst works).
>>
>> Matei
>>
>> > On Jan 13, 2020, at 8:41 AM, Michael Mior <mmior@apache.org> wrote:
>> >
>> > It's fairly common for adapters (Calcite's abstraction of a data
>> > source) to push down predicates. However, the API certainly looks a
>> > lot different than Catalyst's.
>> > --
>> > Michael Mior
>> > mmior@apache.org
>> >
>> > Le lun. 13 janv. 2020 à 09:45, Jason Nerothin
>> > <jasonnerothin@gmail.com> a écrit :
>> >>
>> >> The implementation they chose supports push down predicates, Datasets
>> and other features that are not available in Calcite:
>> >>
>> >> https://databricks.com/glossary/catalyst-optimizer
>> >>
>> >> On Mon, Jan 13, 2020 at 8:24 AM newroyker <newroyker@gmail.com> wrote:
>> >>>
>> >>> Was there a qualitative or quantitative benchmark done before a design
>> >>> decision was made not to use Calcite?
>> >>>
>> >>> Are there limitations (for heuristic based, cost based, * aware
>> optimizer)
>> >>> in Calcite, and frameworks built on top of Calcite? In the context of
>> big
>> >>> data / TCPH benchmarks.
>> >>>
>> >>> I was unable to dig up anything concrete from user group / Jira.
>> Appreciate
>> >>> if any Catalyst veteran here can give me pointers. Trying to defend
>> >>> Spark/Catalyst.
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> --
>> >>> Sent from: http://apache-spark-user-list.1001560.n3.nabble.com/
>> >>>
>> >>> ---------------------------------------------------------------------
>> >>> To unsubscribe e-mail: user-unsubscribe@spark.apache.org
>> >>>
>> >>
>> >>
>> >> --
>> >> Thanks,
>> >> Jason
>> >
>> > ---------------------------------------------------------------------
>> > To unsubscribe e-mail: user-unsubscribe@spark.apache.org
>> >
>>
>>

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