Thanks for taking a look!

> On 27 Apr 2021, at 19:25, Rui Wang <[email protected]> wrote:
> 
> Not every query can be supported by BeamSQL easily. For example, support non 
> equi-join(BEAM-2194).

Could you point me out why "non equi-join” can’t be supported? Either it can 
and this is just a question of implementation?

> We had discussions for cause 2 to add the limitation that BeamSQL only 
> supports ORDER BY LIMIT (LIMIT is required).

I’m curious what is a current implementation of "ORDER BY LIMIT” and can it be 
applied, at least, to only Bounded collection/Global window in the same way for 
"ORDER BY" without limits?

> Cause 3 needs a case by case investigation, some might be able to be fixed.
> Cause 4 looks like no such function found in the catalog. 

I guess it should be "SUBSTRING(<CHARACTER> FROM <NUMERIC> FOR <NUMERIC>)” 
instead of "substr(<CHARACTER>, <NUMERIC>, <NUMERIC>)” ?

—
Alexey

> 
> I’m not very familiar with a current status of ongoing work for Beam SQL, so 
> I’m sorry in advance if my questions will sound naive. 
> 
> Please, guide me on this:
> 
> 1. Are there any chances that we can resolve, at least, partly the current 
> limitations of the query parsing/planning, mentioned above? Are there any 
> principal blockers among them?
> 2. Are there any plans or ongoing work related to this?
> 3. Are there any plans to upgrade vendored Calcite version to more recent 
> one? Should it reduce the number of current limitations or not?
> 4. Do you think it could be valuable for Beam SQL to run TPC-DS benchmark on 
> a regular basis (as we do for Nexmark, for example) even if not all queries 
> can pass with Beam SQL?
>  
> This is definitely valuable for BeamSQL if we have enough resources to run 
> such queries regularly.
> 
> I’d appreciate any additional information/docs/details/opinions on this topic.
> 
> —
> Alexey
> 
> [1] https://github.com/apache/beam/tree/master/sdks/java/testing/tpcds 
> <https://github.com/apache/beam/tree/master/sdks/java/testing/tpcds>
> [2] http://www.tpc.org/tpcds/ <http://www.tpc.org/tpcds/>
> [3] 
> https://docs.google.com/spreadsheets/d/1Gya9Xoa6uWwORHSrRqpkfSII4ajYvDpUTt0cNJCRHjE/edit?usp=sharing
>  
> <https://docs.google.com/spreadsheets/d/1Gya9Xoa6uWwORHSrRqpkfSII4ajYvDpUTt0cNJCRHjE/edit?usp=sharing>
> [4] 
> https://github.com/apache/beam/tree/master/sdks/java/testing/tpcds/src/main/resources/queries
>  
> <https://github.com/apache/beam/tree/master/sdks/java/testing/tpcds/src/main/resources/queries>

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