Yes. I think it makes sense to move to "Future Work" section. Best, Jark
On Thu, 24 Oct 2019 at 17:11, Kurt Young <ykt...@gmail.com> wrote: > +1 to move to a future section. By deleting it I mean remove from > the content describing the current processing procedure. > > Best, > Kurt > > > On Thu, Oct 24, 2019 at 5:01 PM Timo Walther <twal...@apache.org> wrote: > > > Having an MVP and a limited scope sounds good to me. But I would not > > remove the STORED keyword entirely from the document. > > > > It shows that we have a long-term vision. Instead of deleting this > > content, I would move it to a Outlook/Future Work section. > > > > Regards, > > Timo > > > > > > On 24.10.19 10:55, Jark Wu wrote: > > > +1 to remove “STORED” related content. We can add them when user > > requires. > > > Others looks good to me in general. > > > > > > Thanks, > > > Jark > > > > > > > > >> 在 2019年10月24日，14:58，Kurt Young <ykt...@gmail.com> 写道： > > >> > > >> Hi Danny, > > >> > > >> Thanks for preparing this design document. IMO It's a very useful > > >> feature, especially combined with time attribute support to specify > > >> watermark in DDL. > > >> > > >> The design doc looks quite good, but I would suggest to reduce the > > >> scope of the first version. Like we don't have to support "STORED" > > >> in the first MVP version, and you can also delete related content in > > >> document to make it more clean and easier to understand. > > >> > > >> Best, > > >> Kurt > > >> > > >> > > >> On Tue, Sep 17, 2019 at 9:18 PM Qi Luo <luoqi...@gmail.com> wrote: > > >> > > >>> Fantastic! We're also very interested in this feature. > > >>> > > >>> +Boxiu > > >>> > > >>> On Tue, Sep 17, 2019 at 11:31 AM Danny Chan <yuzhao....@gmail.com> > > wrote: > > >>> > > >>>> In umbrella task FLINK-10232 we have introduced CREATE TABLE grammar > > in > > >>>> our new module flink-sql-parser. And we proposed to use computed > > column > > >>> to > > >>>> describe the time attribute of process time in the design doc FLINK > > SQL > > >>>> DDL, so user may create a table with process time attribute as > > follows: > > >>>> create table T1( > > >>>> a int, > > >>>> b bigint, > > >>>> c varchar, > > >>>> d as PROCTIME, > > >>>> ) with ( > > >>>> 'k1' = 'v1', > > >>>> 'k2' = 'v2' > > >>>> ); > > >>>> > > >>>> The column d would be a process time attribute for table T1. > > >>>> > > >>>> Besides that, computed columns have several other use cases, such > as > > >>>> these [2]: > > >>>> > > >>>> > > >>>> • Virtual generated columns can be used as a way to simplify and > unify > > >>>> queries. A complicated condition can be defined as a generated > column > > and > > >>>> referred to from multiple queries on the table to ensure that all of > > them > > >>>> use exactly the same condition. > > >>>> • Stored generated columns can be used as a materialized cache for > > >>>> complicated conditions that are costly to calculate on the fly. > > >>>> • Generated columns can simulate functional indexes: Use a generated > > >>>> column to define a functional expression and index it. This can be > > useful > > >>>> for working with columns of types that cannot be indexed directly, > > such > > >>> as > > >>>> JSON columns. > > >>>> • For stored generated columns, the disadvantage of this approach is > > that > > >>>> values are stored twice; once as the value of the generated column > and > > >>> once > > >>>> in the index. > > >>>> • If a generated column is indexed, the optimizer recognizes query > > >>>> expressions that match the column definition and uses indexes from > the > > >>>> column as appropriate during query execution(Not supported yet). > > >>>> > > >>>> > > >>>> > > >>>> Computed columns are introduced in SQL-SERVER-2016 [1], MYSQL-5.6 > [2] > > and > > >>>> ORACLE-11g [3]. > > >>>> > > >>>> This is the design doc: > > >>>> > > >>>> > > >>> > > > https://docs.google.com/document/d/110TseRtTCphxETPY7uhiHpu-dph3NEesh3mYKtJ7QOY/edit?usp=sharing > > >>>> > > >>>> Any suggestions are appreciated, thanks. > > >>>> > > >>>> [1] > > >>>> > > >>> > > > https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table?view=sql-server-2016 > > >>>> [2] > > >>>> > > >>> > > > https://dev.mysql.com/doc/refman/5.7/en/create-table-generated-columns.html > > >>>> [3] https://oracle-base.com/articles/11g/virtual-columns-11gr1 > > >>>> > > >>>> Best, > > >>>> Danny Chan > > >>>> > > >>> > > > > >
