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Re: [DISCUSS] Flink SQL DDL Design


Hi all,

It's great to see we have an agreement on MVP.

4.b) Ingesting and writing timestamps to systems.
I would treat the field as a physical column not a virtual column. If we
treat it as computed column, it will be confused that the behavior is
different when it is a source or sink.
When it is a physical column, the behavior could be unified. Then the
problem is how to mapping from the field to kafka message timestamp?
One is Lin proposed above and is also used in KSQL[1]. Another idea is
introducing a HEADER column which strictly map by name to the fields in
message header.
For example,

CREATE TABLE output_kafka_t1(
  id bigint,
  ts timestamp HEADER,
  msg varchar
) WITH (
  type=kafka
  ,...
);

This is used in Alibaba but not included in the DDL draft. It will further
extend the SQL syntax, which is we should be cautious about. What do you
think about this two solutions?

4.d) Custom watermark strategies:
@Timo,  I don't have a strong opinion on this.

3) SOURCE/SINK/BOTH
Agree with Lin, GRANT/INVOKE [SELECT|UPDATE] ON TABLE is a clean and
standard way to manage the permission, which is also adopted by HIVE[2] and
many databases.

[1]: https://docs.confluent.io/current/ksql/docs/tutorials/examples.html
[2]:
https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=45876173#Hivedeprecatedauthorizationmode/LegacyMode-Grant/RevokePrivileges

@Timo, it's great if someone can conclude the discussion and summarize into
a FLIP.
@Shuyi, Thanks a lot for putting it all together. The google doc looks good
to me, and I left some minor comments there.

Regarding to the FLIP, I have some suggestions:
1. The FLIP can contain MILESTONE1 and FUTURE WORKS.
2. The MILESTONE1 is the MVP. It describes the MVP DDL syntax.
3. Separate FUTURE WORKS into two parts: UNDER DISCUSSION and ADOPTED. We
can derive MILESTONE2 from this easily when it is ready.

I summarized the Future Works based on Shuyi's work:

Adopted: (Should detailed described here...)
1. support data type nullability and precision.
2. comment on table and columns.

Under Discussion: (Should briefly describe some options...)
1. Ingesting and writing timestamps to systems.
2. support custom watermark strategy.
3. support table update mode
4. support row/map/array data type
5. support schema derivation
6. support system versioned temporal table
7. support table index

We can continue the further discussion here, also can separate to an other
DISCUSS topic if it is a sophisticated problem such as Table Update Mode,
Temporal Table.

Best,
Jark

On Mon, 10 Dec 2018 at 11:54, Lin Li <lincoln.86xy@xxxxxxxxx> wrote:

> hi all,
> Thanks for your valuable input!
>
> 4) Event-Time Attributes and Watermarks:
> 4.b) @Fabian As you mentioned using a computed columns `ts AS
> SYSTEMROWTIME()`
> for writing out to kafka table sink will violate the rule that computed
> fields are not emitted.
> Since the timestamp column in kafka's header area is a specific
> materialization protocol,
> why don't we treat it as an connector property? For an example:
> ```
> CREATE TABLE output_kafka_t1(
>   id bigint,
>   ts timestamp,
>   msg varchar
> ) WITH (
>   type=kafka,
>   header.timestamp=ts
>   ,...
> );
> ```
>
> 4d) For custom watermark strategies
> @Fabian Agree with you that opening another topic about this feature later.
>
> 3) SOURCE / SINK / BOTH
> I think the permissions and availabilities are two separately things,
> permissions
> can be managed well by using GRANT/INVOKE(you can call it DCL) solutions
> which
> commonly used in different DBs. The permission part can be an new topic for
> later discussion, what do you think?
>
> For the availabilities, @Fabian @Timo  I've another question,
> does instantiate a TableSource/Sink cost much or has some other downsides?
> IMO, create a new source/sink object via the construct seems not costly.
> When receiving a DDL we should associate it with the catalog object
> (reusing an existence or create a new one).
> Am I lost something important?
>
> 5. Schema declaration:
> @Timo  yes, your concern about the user convenience is very important. But
> I haven't seen a clear way to solve this so far.
> Do we put it later and wait for more inputs from the community?
>
> Shuyi Chen <suez1224@xxxxxxxxx> 于2018年12月8日周六 下午4:27写道:
>
> > Hi all,
> >
> > Thanks a lot for the great discussion. I think we can continue the
> > discussion here while carving out a MVP so that the community can start
> > working on. Based on the discussion so far, I try to summarize what we
> will
> > do for the MVP:
> >
> > MVP
> >
> >    1. support CREATE TABLE
> >    2. support exisiting data type in Flink SQL, ignore nullability and
> >    precision
> >    3. support table comments and column comments
> >    4. support table constraint PRIMARY KEY and UNIQUE
> >    5. support table properties using key-value pairs
> >    6. support partitioned by
> >    7. support computed column
> >    8. support from-field and from-source timestamp extractors
> >    9. support PERIODIC-ASCENDING, PERIODIC-BOUNDED, FROM-SOURCE watermark
> >    strategies.
> >    10. support a table property to allow explicit enforcement of
> >    read/write(source/sink) permission of a table
> >
> > I try to put up the DDL grammar (
> >
> >
> https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit?usp=sharing
> > )
> > based on the MVP features above and the previous design docs. Please
> take a
> > look and comment on it.
> >
> >
> > Also, I summarize the future Improvement on CREATE TABLE as the
> followings:
> >
> >    1. support table update mode
> >    2. support data type nullability and precision
> >    3. support row/map/array data type
> >    4. support custom timestamp extractor and watermark strategy
> >    5. support schema derivation
> >    6. support system versioned temporal table
> >    7. support table index
> >
> > I suggest we first agree on the MVP feature list and the MVP grammar. And
> > then we can either continue the discussion of the future improvements
> here,
> > or create separate JIRAs for each item and discuss further in the JIRA.
> > What do you guys think?
> >
> > Shuyi
> >
> > On Fri, Dec 7, 2018 at 7:54 AM Timo Walther <twalthr@xxxxxxxxxx> wrote:
> >
> > > Hi all,
> > >
> > > I think we are making good progress. Thanks for all the feedback so
> far.
> > >
> > > 3. Sources/Sinks:
> > > It seems that I can not find supporters for explicit SOURCE/SINK
> > > declaration so I'm fine with not using those keywords.
> > > @Fabian: Maybe we don't haven have to change the TableFactory interface
> > > but just provide some helper functions in the TableFactoryService. This
> > > would solve the availability problem, but the permission problem would
> > > still not be solved. If you are fine with it, we could introduce a
> > > property instead?
> > >
> > > 5. Schema declaration:
> > > @Lin: We should find an agreement on this as it requires changes to the
> > > TableFactory interface. We should minimize changes to this interface
> > > because it is user-facing. Especially, if format schema and table
> schema
> > > differ, the need for such a functionality is very important. Our goal
> is
> > > to connect to existing infrastructure. For example, if we are using
> Avro
> > > and the existing Avro format has enums but Flink SQL does not support
> > > enums, it would be helpful to let the Avro format derive a table
> schema.
> > > Otherwise your need to declare both schemas which leads to CREATE TABLE
> > > statements of 400 lines+.
> > > I think the mentioned query:
> > > CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > format.schema-file = "/my/avrofile.avsc")
> > > is fine and should only be valid if the schema contains no non-computed
> > > columns.
> > >
> > > 7. Table Update Mode:
> > > After thinking about it again, I agree. The mode of the sinks can be
> > > derived from the query and the existence of a PRIMARY KEY declaration.
> > > But Fabian raised a very good point. How do we deal with sources? Shall
> > > we introduce a new keywords similar to WATERMARKS such that a
> > > upsert/retract flag is not part of the visible schema?
> > >
> > > 4a. How to mark a field as attribute?
> > > @Jark: Thanks for the explanation of the WATERMARK clause semantics.
> > > This is a nice way of marking existing fields. This sounds good to me.
> > >
> > > 4c) WATERMARK as constraint
> > > I'm fine with leaving the WATERMARK clause in the schema definition.
> > >
> > > 4d) Custom watermark strategies:
> > > I would already think about custom watermark strategies as the current
> > > descriptor design already supports this. ScalarFunction's don't work as
> > > a PeriodicWatermarkAssigner has different semantics. Why not simply
> > > entering the a full class name here as it is done in the current
> design?
> > >
> > > 4.b) Ingesting and writing timestamps to systems (like Kafka)
> > > @Fabian: Yes, your suggestion sounds good to me. This behavior would be
> > > similar to our current `timestamps: from-source` design.
> > >
> > > Once our discussion has found a conclusion, I would like to volunteer
> > > and summarize the outcome of this mailing thread. It nicely aligns with
> > > the update work on the connector improvements document (that I wanted
> to
> > > do anyway) and the ongoing external catalog discussion. Furthermore, I
> > > would also want to propose how to change existing interfaces by keeping
> > > the DDL, connector improvements, and external catalog support in mind.
> > > Would that be ok for you?
> > >
> > > Thanks,
> > > Timo
> > >
> > >
> > >
> > > Am 07.12.18 um 14:48 schrieb Fabian Hueske:
> > > > Hi all,
> > > >
> > > > Thanks for the discussion.
> > > > I'd like to share my point of view as well.
> > > >
> > > > 4) Event-Time Attributes and Watermarks:
> > > > 4.a) I agree with Lin and Jark's proposal. Declaring a watermark on
> an
> > > > attribute declares it as an event-time attribute.
> > > > 4.b) Ingesting and writing timestamps to systems (like Kafka). We
> could
> > > use
> > > > a special function like (ts AS SYSTEMROWTIME()). This function will
> > > > indicate that we read the timestamp directly from the system (and not
> > the
> > > > data). We can also write the field back to the system when emitting
> the
> > > > table (violating the rule that computed fields are not emitted).
> > > > 4c) I would treat WATERMARK similar to a PRIMARY KEY or UNIQUE KEY
> > > > constraint and therefore keep it in the schema definition.
> > > > 4d) For custom watermark strategies, a simple expressions or
> > > > ScalarFunctions won't be sufficient. Sophisticated approaches could
> > > collect
> > > > histograms, etc. But I think we can leave that out for later.
> > > >
> > > > 3) SOURCE / SINK / BOTH
> > > > As you said, there are two things to consider here: permission and
> > > > availability of a TableSource/TableSink.
> > > > I think that neither should be a reason to add a keyword at such a
> > > > sensitive position.
> > > > However, I also see Timo's point that it would be good to know
> up-front
> > > how
> > > > a table can be used without trying to instantiate a TableSource/Sink
> > for
> > > a
> > > > query.
> > > > Maybe we can extend the TableFactory such that it provides
> information
> > > > about which sources/sinks it can provide.
> > > >
> > > > 7. Table Update Mode
> > > > Something that we definitely need to consider is how tables are
> > ingested,
> > > > i.e., append, retract or upsert.
> > > > Especially, since upsert and retraction need a meta-data column that
> > > > indicates whether an event is an insert (or upsert) or a delete
> change.
> > > > This column needs to be identified somehow, most likely as part of
> the
> > > > input format. Ideally, this column should not be part of the table
> > schema
> > > > (as it would be always true).
> > > > Emitting tables is not so much of an issue as the properties of the
> > table
> > > > tell use what to do (append-only/update, unique key y/n).
> > > >
> > > > Best,
> > > > Fabian
> > > >
> > > >
> > > > Am Fr., 7. Dez. 2018 um 10:39 Uhr schrieb Jark Wu <imjark@xxxxxxxxx
> >:
> > > >
> > > >> Hi Timo,
> > > >>
> > > >> Thanks for your quickly feedback! Here are some of my thoughts:
> > > >>
> > > >> Append, upserts, retract mode on sinks is also a very complex
> > problem. I
> > > >> think append/upserts/retract is the ability of a table, user do not
> > > need to
> > > >> specify a table is used for append or retraction or upsert. The
> query
> > > can
> > > >> choose which mode the sink is. If an unbounded groupby is inserted
> > into
> > > an
> > > >> append sink (the sink only implements/supports append), an exception
> > > can be
> > > >> thrown. A more complex problem is, if we want to write
> > > retractions/upserts
> > > >> to Kafka, how to encode the change flag (add or retract/delete) on
> the
> > > >> table? Maybe we should propose some protocal for the change flag
> > > encoding,
> > > >> but I don't have a clear idea about this right now.
> > > >>
> > > >> 3. Sources/Sinks: The source/sink tag is similar to the
> > > >> append/upsert/retract problem. Besides source/sink, actully we have
> > > stream
> > > >> source, stream sink, batch source, batch sink, and the stream sink
> > also
> > > >> include append/upsert/retract three modes. Should we put all the
> tags
> > on
> > > >> the CREATE TABLE? IMO, the table's ability is defined by the table
> > > itself,
> > > >> user do not need to specify it. If it is only a readable table, an
> > > >> exception can be thrown when write to it. As the source/sink tag can
> > be
> > > >> omitted in CREATE TABLE, could we skip it and only support CREATE
> > TABLE
> > > in
> > > >> the first version, and add it back in the future when we really need
> > > it? It
> > > >> keeps API compatible and make sure the MVP is what we consider
> > clearly.
> > > >>
> > > >> 4a. How to mark a field as attribute?
> > > >> The watermark definition includes two parts: use which field as time
> > > >> attribute and use what generate strategy.
> > > >> When we want to mark `ts` field as attribute: WATERMARK FOR `ts` AS
> > > OFFSET
> > > >> '5' SECOND.
> > > >> If we have a POJO{id, user, ts} field named "pojo", we can mark it
> > like
> > > >> this: WATERMARK FOR pojo.ts AS OFFSET '5' SECOND
> > > >>
> > > >> 4b. timestamp write to Kafka message header
> > > >> Even though we can define multiple time attribute on a table, only
> one
> > > time
> > > >> attribute can be actived/used in a query (in a stream). When we
> enable
> > > >> `writeTiemstamp`, the only attribute actived in the stream will be
> > > write to
> > > >> Kafka message header. What I mean the timestmap in StreamRecord is
> the
> > > time
> > > >> attribute in the stream.
> > > >>
> > > >> 4c. Yes. We introduced the WATERMARK keyword similar to the INDEX,
> > > PRIMARY
> > > >> KEY keywords.
> > > >>
> > > >> @Timo, Do you have any other advice or questions on the watermark
> > > syntax ?
> > > >> For example, the builtin strategy name: "BOUNDED WITH OFFSET" VS
> > > "OFFSET"
> > > >> VS ...
> > > >>
> > > >>
> > > >> Cheers,
> > > >> Jark
> > > >>
> > > >> On Fri, 7 Dec 2018 at 17:13, Lin Li <lincoln.86xy@xxxxxxxxx> wrote:
> > > >>
> > > >>> Hi Timo,
> > > >>> Thanks for your feedback, here's some thoughts of mine:
> > > >>>
> > > >>> 3. Sources/Sinks:
> > > >>> "Let's assume an interactive CLI session, people should be able to
> > list
> > > >> all
> > > >>> source table and sink tables to know upfront if they can use an
> > INSERT
> > > >> INTO
> > > >>> here or not."
> > > >>> This requirement can be simply resolved by a document that list all
> > > >>> supported source/sink/both connectors and the sql-client can
> perform
> > a
> > > >>> quick check. It's only an implementation choice, not necessary for
> > the
> > > >>> syntax.
> > > >>> For connector implementation, a connector may implement one or some
> > or
> > > >> all
> > > >>> of the [Stream|Batch]Source/[Stream|Batch]Sink traits, we can
> derive
> > > the
> > > >>> availability for any give query without the SOURCE/SINk keywords or
> > > >>> specific table properties in WITH clause.
> > > >>> Since there's still indeterminacy, shall we skip these two keywords
> > for
> > > >> the
> > > >>> MVP DDL? We can make further discussion after users' feedback.
> > > >>>
> > > >>> 6. Partitioning and keys
> > > >>> Agree with you that raise the priority of table constraint and
> > > >> partitioned
> > > >>> table support for better connectivity to Hive and Kafka. I'll add
> > > >>> partitioned table syntax(compatible to hive) into the DDL Draft doc
> > > >>> later[1].
> > > >>>
> > > >>> 5. Schema declaration
> > > >>> "if users want to declare computed columns they have a "schema"
> > > >> constraints
> > > >>> but without columns
> > > >>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > >>> format.schema-file = "/my/avrofile.avsc") "
> > > >>>
> > > >>>  From the point of my view, this ddl is invalid because the primary
> > key
> > > >>> constraint already references two columns but types unseen.
> > > >>> And Xuefu pointed a important matching problem, so let's put schema
> > > >>> derivation as a follow-up extension ?
> > > >>>
> > > >>>
> > > >>>
> > > >>>
> > > >>> Timo Walther <twalthr@xxxxxxxxxx> 于2018年12月6日周四 下午6:05写道:
> > > >>>
> > > >>>> Hi everyone,
> > > >>>>
> > > >>>> great to have such a lively discussion. My next batch of feedback:
> > > >>>>
> > > >>>> @Jark: We don't need to align the descriptor approach with SQL.
> I'm
> > > >> open
> > > >>>> for different approaches as long as we can serve a broad set of
> use
> > > >>>> cases and systems. The descriptor approach was a first attempt to
> > > cover
> > > >>>> all aspects and connector/format characteristics. Just another
> > > example,
> > > >>>> that is missing in the DDL design: How can a user decide if
> append,
> > > >>>> retraction, or upserts should be used to sink data into the target
> > > >>>> system? Do we want to define all these improtant properties in the
> > big
> > > >>>> WITH property map? If yes, we are already close to the descriptor
> > > >>>> approach. Regarding the "standard way", most DDL languages have
> very
> > > >>>> custom syntax so there is not a real "standard".
> > > >>>>
> > > >>>> 3. Sources/Sinks: @Lin: If a table has both read/write access it
> can
> > > be
> > > >>>> created using a regular CREATE TABLE (omitting a specific
> > source/sink)
> > > >>>> declaration. Regarding the transition from source/sink to both,
> yes
> > we
> > > >>>> would need to update the a DDL and catalogs. But is this a
> problem?
> > > One
> > > >>>> also needs to add new queries that use the tables. @Xuefu: It is
> not
> > > >>>> only about security aspects. Especially for streaming use cases,
> not
> > > >>>> every connector can be used as a source easily. For example, a
> JDBC
> > > >> sink
> > > >>>> is easier than a JDBC source. Let's assume an interactive CLI
> > session,
> > > >>>> people should be able to list all source table and sink tables to
> > know
> > > >>>> upfront if they can use an INSERT INTO here or not.
> > > >>>>
> > > >>>> 6. Partitioning and keys: @Lin: I would like to include this in
> the
> > > >>>> design given that Hive integration and Kafka key support are in
> the
> > > >>>> making/are on our roadmap for this release.
> > > >>>>
> > > >>>> 5. Schema declaration: @Lin: You are right it is not conflicting.
> I
> > > >> just
> > > >>>> wanted to raise the point because if users want to declare
> computed
> > > >>>> columns they have a "schema" constraints but without columns. Are
> we
> > > ok
> > > >>>> with a syntax like ...
> > > >>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > >>>> format.schema-file = "/my/avrofile.avsc") ?
> > > >>>> @Xuefu: Yes, you are right that an external schema might not
> excatly
> > > >>>> match but this is true for both directions:
> > > >>>> table schema "derives" format schema and format schema "derives"
> > table
> > > >>>> schema.
> > > >>>>
> > > >>>> 7. Hive compatibility: @Xuefu: I agree that Hive is popular but we
> > > >>>> should not just adopt everything from Hive as there syntax is very
> > > >>>> batch-specific. We should come up with a superset of historical
> and
> > > >>>> future requirements. Supporting Hive queries can be an
> intermediate
> > > >>>> layer on top of Flink's DDL.
> > > >>>>
> > > >>>> 4. Time attributes: @Lin: I'm fine with changing the
> > > TimestampExtractor
> > > >>>> interface as this is also important for better separation of
> > connector
> > > >>>> and table module [1]. However, I'm wondering about watermark
> > > >> generation.
> > > >>>> 4a. timestamps are in the schema twice:
> > > >>>> @Jark: "existing field is Long/Timestamp, we can just use it as
> > > >>>> rowtime": yes, but we need to mark a field as such an attribute.
> How
> > > >>>> does the syntax for marking look like? Also in case of timestamps
> > that
> > > >>>> are nested in the schema?
> > > >>>>
> > > >>>> 4b. how can we write out a timestamp into the message header?:
> > > >>>> I agree to simply ignore computed columns when writing out. This
> is
> > > >> like
> > > >>>> 'field-change: add' that I mentioned in the improvements document.
> > > >>>> @Jark: "then the timestmap in StreamRecord will be write to Kafka
> > > >>>> message header": Unfortunately, there is no timestamp in the
> stream
> > > >>>> record. Additionally, multiple time attributes can be in a schema.
> > So
> > > >> we
> > > >>>> need a constraint that tells the sink which column to use
> (possibly
> > > >>>> computed as well)?
> > > >>>>
> > > >>>> 4c. separate all time attribute concerns into a special clause
> next
> > to
> > > >>>> the regular schema?
> > > >>>> @Jark: I don't have a strong opinion on this. I just have the
> > feeling
> > > >>>> that the "schema part" becomes quite messy because the actual
> schema
> > > >>>> with types and fields is accompanied by so much metadata about
> > > >>>> timestamps, watermarks, keys,... and we would need to introduce a
> > new
> > > >>>> WATERMARK keyword within a schema that was close to standard up to
> > > this
> > > >>>> point.
> > > >>>>
> > > >>>> Thanks everyone,
> > > >>>> Timo
> > > >>>>
> > > >>>> [1] https://issues.apache.org/jira/browse/FLINK-9461
> > > >>>>
> > > >>>>
> > > >>>>
> > > >>>> Am 06.12.18 um 07:08 schrieb Jark Wu:
> > > >>>>> Hi Timo,
> > > >>>>>
> > > >>>>> Thank you for the valuable feedbacks.
> > > >>>>>
> > > >>>>> First of all, I think we don't need to align the SQL
> functionality
> > to
> > > >>>>> Descriptor. Because SQL is a more standard API, we should be as
> > > >>> cautious
> > > >>>> as
> > > >>>>> possible to extend the SQL syntax. If something can be done in a
> > > >>> standard
> > > >>>>> way, we shouldn't introduce something new.
> > > >>>>>
> > > >>>>> Here are some of my thoughts:
> > > >>>>>
> > > >>>>> 1. Scope: Agree.
> > > >>>>> 2. Constraints: Agree.
> > > >>>>> 4. Time attributes:
> > > >>>>>     4a. timestamps are in the schema twice.
> > > >>>>>      If an existing field is Long/Timestamp, we can just use it
> as
> > > >>>> rowtime,
> > > >>>>> no twice defined. If it is not a Long/Timestamp, we use computed
> > > >> column
> > > >>>> to
> > > >>>>> get an expected timestamp column to be rowtime, is this what you
> > mean
> > > >>>>> defined twice?  But I don't think it is a problem, but an
> > advantages,
> > > >>>>> because it is easy to use, user do not need to consider whether
> to
> > > >>>> "replace
> > > >>>>> the existing column" or "add a new column", he will not be
> confused
> > > >>>> what's
> > > >>>>> the real schema is, what's the index of rowtime in the schema?
> > > >>> Regarding
> > > >>>> to
> > > >>>>> the optimization, even if timestamps are in schema twice, when
> the
> > > >>>> original
> > > >>>>> timestamp is never used in query, then the projection pushdown
> > > >>>> optimization
> > > >>>>> can cut this field as early as possible, which is exactly the
> same
> > as
> > > >>>>> "replacing the existing column" in runtime.
> > > >>>>>
> > > >>>>>      4b. how can we write out a timestamp into the message
> header?
> > > >>>>>       That's a good point. I think computed column is just a
> > virtual
> > > >>>> column
> > > >>>>> on table which is only relative to reading. If we want to write
> to
> > a
> > > >>>> table
> > > >>>>> with computed column defined, we only need to provide the columns
> > > >>> except
> > > >>>>> computed columns (see SQL Server [1]). The computed column is
> > ignored
> > > >>> in
> > > >>>>> the insert statement. Get back to the question, how can we write
> > out
> > > >> a
> > > >>>>> timestamp into the message header? IMO, we can provide a
> > > >> configuration
> > > >>> to
> > > >>>>> support this, such as `kafka.writeTimestamp=true`, then the
> > timestmap
> > > >>> in
> > > >>>>> StreamRecord will be write to Kafka message header. What do you
> > > >> think?
> > > >>>>>       4c. separate all time attribute concerns into a special
> > clause
> > > >>> next
> > > >>>> to
> > > >>>>> the regular schema?
> > > >>>>>       Separating watermark into a special clause similar to
> > > >> PARTITIONED
> > > >>>> BY is
> > > >>>>> also a good idea. Conceptually, it's fine to put watermark in
> > schema
> > > >>> part
> > > >>>>> or out schema part. But if we want to support multiple watermark
> > > >>>>> definition, maybe it would be better to put it in schema part. It
> > is
> > > >>>>> similar to Index Definition that we can define several indexes
> on a
> > > >>> table
> > > >>>>> in schema part.
> > > >>>>>
> > > >>>>>       4d. How can people come up with a custom watermark
> strategy?
> > > >>>>>       In most cases, the built-in strategy can works good. If we
> > need
> > > >> a
> > > >>>>> custom one, we can use a scalar function which restrict to only
> > > >> return
> > > >>> a
> > > >>>>> nullable Long, and use it in SQL like: WATERMARK for rowtime AS
> > > >>>>> watermarkUdf(a, b, c). The `watermarkUdf` is a user-defined
> scalar
> > > >>>> function
> > > >>>>> accepts 3 parameters and return a nullable Long which can be used
> > as
> > > >>>>> punctuated watermark assigner. Another choice is implementing a
> > class
> > > >>>>> extending the
> > > >>>>> `org.apache.flink.table.sources.wmstrategies.WatermarkStrategy`
> and
> > > >> use
> > > >>>> it
> > > >>>>> in SQL: WATERMARK for rowtime AS 'com.my.MyWatermarkStrategy'.
> But
> > if
> > > >>>>> scalar function can cover the requirements here, I would prefer
> it
> > > >>> here,
> > > >>>>> because it keeps standard compliant. BTW, this feature is not in
> > MVP,
> > > >>> we
> > > >>>>> can discuss it more depth in the future when we need it.
> > > >>>>>
> > > >>>>> 5. Schema declaration:
> > > >>>>> I like the proposal to omit the schema if we can get the schema
> > from
> > > >>>>> external storage or something schema file. Actually, we have
> > already
> > > >>>>> encountered this requirement in out company.
> > > >>>>>
> > > >>>>>
> > > >>>>> +1 to @Xuefu that we should be as close as possible to Hive
> syntax
> > > >>> while
> > > >>>>> keeping SQL ANSI standard. This will make it more acceptable and
> > > >> reduce
> > > >>>> the
> > > >>>>> learning cost for user.
> > > >>>>>
> > > >>>>> [1]:
> > > >>>>>
> > > >>
> > >
> >
> https://docs.microsoft.com/en-us/sql/relational-databases/partitions/create-partitioned-tables-and-indexes?view=sql-server-2017
> > > >>>>> Best,
> > > >>>>> Jark
> > > >>>>>
> > > >>>>> On Thu, 6 Dec 2018 at 12:09, Zhang, Xuefu <
> xuefu.z@xxxxxxxxxxxxxxx
> > >
> > > >>>> wrote:
> > > >>>>>> Hi Timo/Shuyi/Lin,
> > > >>>>>>
> > > >>>>>> Thanks for the discussions. It seems that we are converging to
> > > >>> something
> > > >>>>>> meaningful. Here are some of my thoughts:
> > > >>>>>>
> > > >>>>>> 1. +1 on MVP DDL
> > > >>>>>> 3. Markers for source or sink seem more about permissions on
> > tables
> > > >>> that
> > > >>>>>> belong to a security component. Unless the table is created
> > > >>> differently
> > > >>>>>> based on source, sink, or both, it doesn't seem necessary to use
> > > >> these
> > > >>>>>> keywords to enforce permissions.
> > > >>>>>> 5. It might be okay if schema declaration is always needed.
> While
> > > >>> there
> > > >>>>>> might be some duplication sometimes, it's not always true. For
> > > >>> example,
> > > >>>>>> external schema may not be exactly matching Flink schema. For
> > > >>> instance,
> > > >>>>>> data types. Even if so, perfect match is not required. For
> > instance,
> > > >>> the
> > > >>>>>> external schema file may evolve while table schema in Flink may
> > stay
> > > >>>>>> unchanged. A responsible reader should be able to scan the file
> > > >> based
> > > >>> on
> > > >>>>>> file schema and return the data based on table schema.
> > > >>>>>>
> > > >>>>>> Other aspects:
> > > >>>>>>
> > > >>>>>> 7. Hive compatibility. Since Flink SQL will soon be able to
> > operate
> > > >> on
> > > >>>>>> Hive metadata and data, it's an add-on benefit if we can be
> > > >> compatible
> > > >>>> with
> > > >>>>>> Hive syntax/semantics while following ANSI standard. At least we
> > > >>> should
> > > >>>> be
> > > >>>>>> as close as possible. Hive DDL can found at
> > > >>>>>>
> > https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL
> > > >>>>>>
> > > >>>>>> Thanks,
> > > >>>>>> Xuefu
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>
> ------------------------------------------------------------------
> > > >>>>>> Sender:Lin Li <lincoln.86xy@xxxxxxxxx>
> > > >>>>>> Sent at:2018 Dec 6 (Thu) 10:49
> > > >>>>>> Recipient:dev <dev@xxxxxxxxxxxxxxxx>
> > > >>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> > > >>>>>>
> > > >>>>>> Hi Timo and Shuyi,
> > > >>>>>>     thanks for your feedback.
> > > >>>>>>
> > > >>>>>> 1. Scope
> > > >>>>>> agree with you we should focus on the MVP DDL first.
> > > >>>>>>
> > > >>>>>> 2. Constraints
> > > >>>>>> yes, this can be a follow-up issue.
> > > >>>>>>
> > > >>>>>> 3. Sources/Sinks
> > > >>>>>> If a TABLE has both read/write access requirements, should we
> > > >> declare
> > > >>> it
> > > >>>>>> using
> > > >>>>>> `CREATE [SOURCE_SINK|BOTH] TABLE tableName ...` ? A further
> > > >> question,
> > > >>>> if a
> > > >>>>>> TABLE
> > > >>>>>> t1 firstly declared as read only (as a source table), then for
> > some
> > > >>> new
> > > >>>>>> requirements
> > > >>>>>> t1 will change to a sink table,  in this case we need updating
> > both
> > > >>> the
> > > >>>> DDL
> > > >>>>>> and catalogs.
> > > >>>>>> Further more, let's think about the BATCH query, update one
> table
> > > >>>> in-place
> > > >>>>>> can be a common case.
> > > >>>>>> e.g.,
> > > >>>>>> ```
> > > >>>>>> CREATE TABLE t1 (
> > > >>>>>>     col1 varchar,
> > > >>>>>>     col2 int,
> > > >>>>>>     col3 varchar
> > > >>>>>>     ...
> > > >>>>>> );
> > > >>>>>>
> > > >>>>>> INSERT [OVERWRITE] TABLE t1
> > > >>>>>> AS
> > > >>>>>> SELECT
> > > >>>>>>     (some computing ...)
> > > >>>>>> FROM t1;
> > > >>>>>> ```
> > > >>>>>> So, let's forget these SOURCE/SINK keywords in DDL. For the
> > > >> validation
> > > >>>>>> purpose, we can find out other ways.
> > > >>>>>>
> > > >>>>>> 4. Time attributes
> > > >>>>>> As Shuyi mentioned before, there exists an
> > > >>>>>> `org.apache.flink.table.sources.tsextractors.TimestampExtractor`
> > for
> > > >>>> custom
> > > >>>>>> defined time attributes usage, but this expression based class
> is
> > > >> more
> > > >>>>>> friendly for table api not the SQL.
> > > >>>>>> ```
> > > >>>>>> /**
> > > >>>>>>     * Provides the an expression to extract the timestamp for a
> > > >> rowtime
> > > >>>>>> attribute.
> > > >>>>>>     */
> > > >>>>>> abstract class TimestampExtractor extends FieldComputer[Long]
> with
> > > >>>>>> Serializable {
> > > >>>>>>
> > > >>>>>>     /** Timestamp extractors compute the timestamp as Long. */
> > > >>>>>>     override def getReturnType: TypeInformation[Long] =
> > > >>>>>> Types.LONG.asInstanceOf[TypeInformation[Long]]
> > > >>>>>> }
> > > >>>>>> ```
> > > >>>>>> BTW, I think both the Scalar function and the TimestampExtractor
> > are
> > > >>>>>> expressing computing logic, the TimestampExtractor has no more
> > > >>>> advantage in
> > > >>>>>> SQL scenarios.
> > > >>>>>>
> > > >>>>>>
> > > >>>>>> 6. Partitioning and keys
> > > >>>>>> Primary Key is included in Constraint part, and partitioned
> table
> > > >>>> support
> > > >>>>>> can be another topic later.
> > > >>>>>>
> > > >>>>>> 5. Schema declaration
> > > >>>>>> Agree with you that we can do better schema derivation for user
> > > >>>>>> convenience, but this is not conflict with the syntax.
> > > >>>>>> Table properties can carry any useful informations both for the
> > > >> users
> > > >>>> and
> > > >>>>>> the framework, I like your `contract name` proposal,
> > > >>>>>> e.g., `WITH (format.type = avro)`, the framework can recognize
> > some
> > > >>>>>> `contract name` like `format.type`, `connector.type` and etc.
> > > >>>>>> And also derive the table schema from an existing schema file
> can
> > be
> > > >>>> handy
> > > >>>>>> especially one with too many table columns.
> > > >>>>>>
> > > >>>>>> Regards,
> > > >>>>>> Lin
> > > >>>>>>
> > > >>>>>>
> > > >>>>>> Timo Walther <twalthr@xxxxxxxxxx> 于2018年12月5日周三 下午10:40写道:
> > > >>>>>>
> > > >>>>>>> Hi Jark and Shuyi,
> > > >>>>>>>
> > > >>>>>>> thanks for pushing the DDL efforts forward. I agree that we
> > should
> > > >>> aim
> > > >>>>>>> to combine both Shuyi's design and your design.
> > > >>>>>>>
> > > >>>>>>> Here are a couple of concerns that I think we should address in
> > the
> > > >>>>>> design:
> > > >>>>>>> 1. Scope: Let's focuses on a MVP DDL for CREATE TABLE
> statements
> > > >>> first.
> > > >>>>>>> I think this topic has already enough potential for long
> > > >> discussions
> > > >>>> and
> > > >>>>>>> is very helpful for users. We can discuss CREATE VIEW and
> CREATE
> > > >>>>>>> FUNCTION afterwards as they are not related to each other.
> > > >>>>>>>
> > > >>>>>>> 2. Constraints: I think we should consider things like
> > nullability,
> > > >>>>>>> VARCHAR length, and decimal scale and precision in the future
> as
> > > >> they
> > > >>>>>>> allow for nice optimizations. However, since both the
> translation
> > > >> and
> > > >>>>>>> runtime operators do not support those features. I would not
> > > >>> introduce
> > > >>>> a
> > > >>>>>>> arbitrary default value but omit those parameters for now. This
> > can
> > > >>> be
> > > >>>> a
> > > >>>>>>> follow-up issue once the basic DDL has been merged.
> > > >>>>>>>
> > > >>>>>>> 3. Sources/Sinks: We had a discussion about CREATE TABLE vs
> > CREATE
> > > >>>>>>> [SOURCE|SINK|] TABLE before. In my opinion we should allow for
> > > >> these
> > > >>>>>>> explicit declaration because in most production scenarios,
> teams
> > > >> have
> > > >>>>>>> strict read/write access requirements. For example, a data
> > science
> > > >>> team
> > > >>>>>>> should only consume from a event Kafka topic but should not
> > > >>> accidently
> > > >>>>>>> write back to the single source of truth.
> > > >>>>>>>
> > > >>>>>>> 4. Time attributes: In general, I like your computed columns
> > > >> approach
> > > >>>>>>> because it makes defining a rowtime attributes transparent and
> > > >>> simple.
> > > >>>>>>> However, there are downsides that we should discuss.
> > > >>>>>>> 4a. Jarks current design means that timestamps are in the
> schema
> > > >>> twice.
> > > >>>>>>> The design that is mentioned in [1] makes this more flexible as
> > it
> > > >>>>>>> either allows to replace an existing column or add a computed
> > > >> column.
> > > >>>>>>> 4b. We need to consider the zoo of storage systems that is out
> > > >> there
> > > >>>>>>> right now. Take Kafka as an example, how can we write out a
> > > >> timestamp
> > > >>>>>>> into the message header? We need to think of a reverse
> operation
> > > >> to a
> > > >>>>>>> computed column.
> > > >>>>>>> 4c. Does defining a watermark really fit into the schema part
> of
> > a
> > > >>>>>>> table? Shouldn't we separate all time attribute concerns into a
> > > >>> special
> > > >>>>>>> clause next to the regular schema, similar how PARTITIONED BY
> > does
> > > >> it
> > > >>>> in
> > > >>>>>>> Hive?
> > > >>>>>>> 4d. How can people come up with a custom watermark strategy? I
> > > >> guess
> > > >>>>>>> this can not be implemented in a scalar function and would
> > require
> > > >>> some
> > > >>>>>>> new type of UDF?
> > > >>>>>>>
> > > >>>>>>> 6. Partitioning and keys: Another question that the DDL design
> > > >> should
> > > >>>>>>> answer is how do we express primary keys (for upserts),
> > > >> partitioning
> > > >>>>>>> keys (for Hive, Kafka message keys). All part of the table
> > schema?
> > > >>>>>>>
> > > >>>>>>> 5. Schema declaration: I find it very annoying that we want to
> > > >> force
> > > >>>>>>> people to declare all columns and types again even though this
> is
> > > >>>>>>> usually already defined in some company-wide format. I know
> that
> > > >>>> catalog
> > > >>>>>>> support will greatly improve this. But if no catalog is used,
> > > >> people
> > > >>>>>>> need to manually define a schema with 50+ fields in a Flink
> DDL.
> > > >>> What I
> > > >>>>>>> actually promoted having two ways of reading data:
> > > >>>>>>>
> > > >>>>>>> 1. Either the format derives its schema from the table schema.
> > > >>>>>>> CREATE TABLE (col INT) WITH (format.type = avro)
> > > >>>>>>>
> > > >>>>>>> 2. Or the table schema can be omitted and the format schema
> > defines
> > > >>> the
> > > >>>>>>> table schema (+ time attributes).
> > > >>>>>>> CREATE TABLE WITH (format.type = avro, format.schema-file =
> > > >>>>>>> "/my/avrofile.avsc")
> > > >>>>>>>
> > > >>>>>>> Please let me know what you think about each item. I will try
> to
> > > >>>>>>> incorporate your feedback in [1] this week.
> > > >>>>>>>
> > > >>>>>>> Regards,
> > > >>>>>>> Timo
> > > >>>>>>>
> > > >>>>>>> [1]
> > > >>>>>>>
> > > >>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit#heading=h.41fd6rs7b3cf
> > > >>>>>>> Am 05.12.18 um 13:01 schrieb Jark Wu:
> > > >>>>>>>> Hi Shuyi,
> > > >>>>>>>>
> > > >>>>>>>> It's exciting to see we can make such a great progress here.
> > > >>>>>>>>
> > > >>>>>>>> Regarding to the watermark:
> > > >>>>>>>>
> > > >>>>>>>> Watermarks can be defined on any columns (including
> > > >> computed-column)
> > > >>>> in
> > > >>>>>>>> table schema.
> > > >>>>>>>> The computed column can be computed from existing columns
> using
> > > >>>> builtin
> > > >>>>>>>> functions and *UserDefinedFunctions* (ScalarFunction).
> > > >>>>>>>> So IMO, it can work out for almost all the scenarios not only
> > > >> common
> > > >>>>>>>> scenarios.
> > > >>>>>>>>
> > > >>>>>>>> I don't think using a `TimestampExtractor` to support custom
> > > >>> timestamp
> > > >>>>>>>> extractor in SQL is a good idea. Because `TimestampExtractor`
> > > >>>>>>>> is not a SQL standard function. If we support
> > `TimestampExtractor`
> > > >>> in
> > > >>>>>>> SQL,
> > > >>>>>>>> do we need to support CREATE FUNCTION for
> `TimestampExtractor`?
> > > >>>>>>>> I think `ScalarFunction` can do the same thing with
> > > >>>>>> `TimestampExtractor`
> > > >>>>>>>> but more powerful and standard.
> > > >>>>>>>>
> > > >>>>>>>> The core idea of the watermark definition syntax is that the
> > > >> schema
> > > >>>>>> part
> > > >>>>>>>> defines all the columns of the table, it is exactly what the
> > query
> > > >>>>>> sees.
> > > >>>>>>>> The watermark part is something like a primary key definition
> or
> > > >>>>>>> constraint
> > > >>>>>>>> on SQL Table, it has no side effect on the schema, only
> defines
> > > >> what
> > > >>>>>>>> watermark strategy is and makes which field as the rowtime
> > > >> attribute
> > > >>>>>>> field.
> > > >>>>>>>> If the rowtime field is not in the existing fields, we can use
> > > >>>> computed
> > > >>>>>>>> column
> > > >>>>>>>> to generate it from other existing fields. The Descriptor
> > Pattern
> > > >>> API
> > > >>>>>> [1]
> > > >>>>>>>> is very useful when writing a Table API job, but is not
> > > >>> contradictory
> > > >>>>>> to
> > > >>>>>>>> the
> > > >>>>>>>> Watermark DDL from my perspective.
> > > >>>>>>>>
> > > >>>>>>>> [1]:
> > > >>>>>>>>
> > > >>
> > >
> >
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> > > >>>>>>>> .
> > > >>>>>>>>
> > > >>>>>>>> Best,
> > > >>>>>>>> Jark
> > > >>>>>>>>
> > > >>>>>>>> On Wed, 5 Dec 2018 at 17:58, Shuyi Chen <suez1224@xxxxxxxxx>
> > > >> wrote:
> > > >>>>>>>>> Hi Jark and Shaoxuan,
> > > >>>>>>>>>
> > > >>>>>>>>> Thanks a lot for the summary. I think we are making great
> > > >> progress
> > > >>>>>> here.
> > > >>>>>>>>> Below are my thoughts.
> > > >>>>>>>>>
> > > >>>>>>>>> *(1) watermark definition
> > > >>>>>>>>> IMO, it's better to keep it consistent with the rowtime
> > > >> extractors
> > > >>>> and
> > > >>>>>>>>> watermark strategies defined in
> > > >>>>>>>>>
> > > >>>>>>>>>
> > > >>
> > >
> >
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> > > >>>>>>>>> .
> > > >>>>>>>>> Using built-in functions seems to be too much for most of the
> > > >>> common
> > > >>>>>>>>> scenarios.
> > > >>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> > > >>>>>>>>> Actually, I think we can put the source/sink type info into
> the
> > > >>> table
> > > >>>>>>>>> properties, so we can use CREATE TABLE.
> > > >>>>>>>>> (3) View DDL with properties
> > > >>>>>>>>> We can remove the view properties section now for the MVP and
> > add
> > > >>> it
> > > >>>>>>> back
> > > >>>>>>>>> later if needed.
> > > >>>>>>>>> (4) Type Definition
> > > >>>>>>>>> I agree we can put the type length or precision into future
> > > >>> versions.
> > > >>>>>> As
> > > >>>>>>>>> for the grammar difference, currently, I am using the grammar
> > in
> > > >>>>>> Calcite
> > > >>>>>>>>> type DDL, but since we'll extend the parser in Flink, so we
> can
> > > >>>>>>> definitely
> > > >>>>>>>>> change if needed.
> > > >>>>>>>>>
> > > >>>>>>>>> Shuyi
> > > >>>>>>>>>
> > > >>>>>>>>> On Tue, Dec 4, 2018 at 10:48 PM Jark Wu <imjark@xxxxxxxxx>
> > > >> wrote:
> > > >>>>>>>>>> Hi Shaoxuan,
> > > >>>>>>>>>>
> > > >>>>>>>>>> Thanks for pointing that out. Yes, the source/sink tag on
> > create
> > > >>>>>> table
> > > >>>>>>> is
> > > >>>>>>>>>> the another major difference.
> > > >>>>>>>>>>
> > > >>>>>>>>>> Summarize the main differences again:
> > > >>>>>>>>>>
> > > >>>>>>>>>> *(1) watermark definition
> > > >>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> > > >>>>>>>>>> (3) View DDL with properties
> > > >>>>>>>>>> (4) Type Definition
> > > >>>>>>>>>>
> > > >>>>>>>>>> Best,
> > > >>>>>>>>>> Jark
> > > >>>>>>>>>>
> > > >>>>>>>>>> On Wed, 5 Dec 2018 at 14:08, Shaoxuan Wang <
> > wshaoxuan@xxxxxxxxx
> > > >>>>>>> wrote:
> > > >>>>>>>>>>> Hi Jark,
> > > >>>>>>>>>>> Thanks for the summary. Your plan for the 1st round
> > > >>> implementation
> > > >>>>>> of
> > > >>>>>>>>> DDL
> > > >>>>>>>>>>> looks good to me.
> > > >>>>>>>>>>> Have we reached the agreement on simplifying/unifying
> "create
> > > >>>>>>>>>> [source/sink]
> > > >>>>>>>>>>> table" to "create table"? "Watermark definition" and
> "create
> > > >>> table"
> > > >>>>>>> are
> > > >>>>>>>>>> the
> > > >>>>>>>>>>> major obstacles on the way to merge two design proposals
> > FMPOV.
> > > >>>>>>> @Shuyi,
> > > >>>>>>>>>> It
> > > >>>>>>>>>>> would be great if you can spend time and respond to these
> two
> > > >>> parts
> > > >>>>>>>>>> first.
> > > >>>>>>>>>>> Regards,
> > > >>>>>>>>>>> Shaoxuan
> > > >>>>>>>>>>>
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> On Wed, Dec 5, 2018 at 12:20 PM Jark Wu <imjark@xxxxxxxxx>
> > > >>> wrote:
> > > >>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> It seems that you have reviewed the DDL doc [1] that Lin
> > and I
> > > >>>>>>>>> drafted.
> > > >>>>>>>>>>>> This doc covers all the features running in Alibaba.
> > > >>>>>>>>>>>> But some of features might be not needed in the first
> > version
> > > >> of
> > > >>>>>>>>> Flink
> > > >>>>>>>>>>> SQL
> > > >>>>>>>>>>>> DDL.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> So my suggestion would be to focus on the MVP DDLs and
> reach
> > > >>>>>>>>> agreement
> > > >>>>>>>>>>> ASAP
> > > >>>>>>>>>>>> based on the DDL draft [1] and the DDL design [2] Shuyi
> > > >>> proposed.
> > > >>>>>>>>>>>> And we can discuss on the main differences one by one.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> The following is the MVP DDLs should be included in the
> > first
> > > >>>>>> version
> > > >>>>>>>>>> in
> > > >>>>>>>>>>> my
> > > >>>>>>>>>>>> opinion (feedbacks are welcome):
> > > >>>>>>>>>>>> (1) Table DDL:
> > > >>>>>>>>>>>>        (1.1) Type definition
> > > >>>>>>>>>>>>        (1.2) computed column definition
> > > >>>>>>>>>>>>        (1.3) watermark definition
> > > >>>>>>>>>>>>        (1.4) with properties
> > > >>>>>>>>>>>>        (1.5) table constraint (primary key/unique)
> > > >>>>>>>>>>>>        (1.6) column nullability (nice to have)
> > > >>>>>>>>>>>> (2) View DDL
> > > >>>>>>>>>>>> (3) Function DDL
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> The main differences from two DDL docs (sth maybe missed,
> > > >>> welcome
> > > >>>>>> to
> > > >>>>>>>>>>> point
> > > >>>>>>>>>>>> out):
> > > >>>>>>>>>>>> *(1.3) watermark*: this is the main and the most important
> > > >>>>>>>>> difference,
> > > >>>>>>>>>> it
> > > >>>>>>>>>>>> would be great if @Timo Walther <twalthr@xxxxxxxxxx>
> > @Fabian
> > > >>>>>> Hueske
> > > >>>>>>>>>>>> <fhueske@xxxxxxxxx>  give some feedbacks.
> > > >>>>>>>>>>>>     (1.1) Type definition:
> > > >>>>>>>>>>>>          (a) Should VARCHAR carry a length, e.g.
> > VARCHAR(128)
> > > ?
> > > >>>>>>>>>>>>               In most cases, the varchar length is not
> used
> > > >>> because
> > > >>>>>>> they
> > > >>>>>>>>>> are
> > > >>>>>>>>>>>> stored as String in Flink. But it can be used to optimize
> in
> > > >> the
> > > >>>>>>>>> future
> > > >>>>>>>>>>> if
> > > >>>>>>>>>>>> we know the column is a fixed length VARCHAR.
> > > >>>>>>>>>>>>               So IMO, we can support VARCHAR with length
> in
> > > the
> > > >>>>>> future,
> > > >>>>>>>>>> and
> > > >>>>>>>>>>>> just VARCHAR in this version.
> > > >>>>>>>>>>>>          (b) Should DECIMAL support custom scale and
> > > precision,
> > > >>>> e.g.
> > > >>>>>>>>>>>> DECIMAL(12, 5)?
> > > >>>>>>>>>>>>               If we clearly know the scale and precision
> of
> > > the
> > > >>>>>>> Decimal,
> > > >>>>>>>>>> we
> > > >>>>>>>>>>>> can have some optimization on
> serialization/deserialization.
> > > >>> IMO,
> > > >>>>>> we
> > > >>>>>>>>>> can
> > > >>>>>>>>>>>> support just support DECIMAL in this version,
> > > >>>>>>>>>>>>               which means DECIMAL(38, 18) as default. And
> > > >> support
> > > >>>>>>> custom
> > > >>>>>>>>>>> scale
> > > >>>>>>>>>>>> and precision in the future.
> > > >>>>>>>>>>>>     (2) View DDL: Do we need WITH properties in View DDL
> > > >>> (proposed
> > > >>>> in
> > > >>>>>>>>>>> doc[2])?
> > > >>>>>>>>>>>> What are the properties on the view used for?
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> The features could be supported and discussed in the
> future:
> > > >>>>>>>>>>>> (1) period definition on table
> > > >>>>>>>>>>>> (2) Type DDL
> > > >>>>>>>>>>>> (3) Index DDL
> > > >>>>>>>>>>>> (4) Library DDL
> > > >>>>>>>>>>>> (5) Drop statement
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> [1] Flink DDL draft by Lin and Jark:
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1o16jC-AxnZoxMfHQptkKQkSC6ZDDBRhKg6gm8VGnY-k/edit#
> > > >>>>>>>>>>>> [2] Flink SQL DDL design by Shuyi:
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit#
> > > >>>>>>>>>>>> Cheers,
> > > >>>>>>>>>>>> Jark
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> On Thu, 29 Nov 2018 at 16:13, Shaoxuan Wang <
> > > >>> wshaoxuan@xxxxxxxxx>
> > > >>>>>>>>>> wrote:
> > > >>>>>>>>>>>>> Sure Shuyu,
> > > >>>>>>>>>>>>> What I hope is that we can reach an agreement on DDL
> gramma
> > > >> as
> > > >>>>>> soon
> > > >>>>>>>>>> as
> > > >>>>>>>>>>>>> possible. There are a few differences between your
> proposal
> > > >> and
> > > >>>>>>>>> ours.
> > > >>>>>>>>>>>> Once
> > > >>>>>>>>>>>>> Lin and Jark propose our design, we can quickly discuss
> on
> > > >> the
> > > >>>>>>>>> those
> > > >>>>>>>>>>>>> differences, and see how far away towards a unified
> design.
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> WRT the external catalog, I think it is an orthogonal
> > topic,
> > > >> we
> > > >>>>>> can
> > > >>>>>>>>>>>> design
> > > >>>>>>>>>>>>> it in parallel. I believe @Xuefu, @Bowen are already
> > working
> > > >>> on.
> > > >>>>>> We
> > > >>>>>>>>>>>>> should/will definitely involve them to review the final
> > > >> design
> > > >>> of
> > > >>>>>>>>> DDL
> > > >>>>>>>>>>>>> implementation. I would suggest that we should give it a
> > > >> higher
> > > >>>>>>>>>>> priority
> > > >>>>>>>>>>>> on
> > > >>>>>>>>>>>>> the DDL implementation, as it is a crucial component for
> > the
> > > >>> user
> > > >>>>>>>>>>>>> experience of SQL_CLI.
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> Regards,
> > > >>>>>>>>>>>>> Shaoxuan
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> On Thu, Nov 29, 2018 at 6:56 AM Shuyi Chen <
> > > >> suez1224@xxxxxxxxx
> > > >>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>> Thanks a lot, Shaoxuan, Jack and Lin. We should
> definitely
> > > >>>>>>>>>>> collaborate
> > > >>>>>>>>>>>>>> here, we have also our own DDL implementation running in
> > > >>>>>>>>> production
> > > >>>>>>>>>>> for
> > > >>>>>>>>>>>>>> almost 2 years at Uber. With the joint experience from
> > both
> > > >>>>>>>>>>> companies,
> > > >>>>>>>>>>>> we
> > > >>>>>>>>>>>>>> can definitely make the Flink SQL DDL better.
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> As @shaoxuan suggest, Jark can come up with a doc that
> > talks
> > > >>>>>>>>> about
> > > >>>>>>>>>>> the
> > > >>>>>>>>>>>>>> current DDL design in Alibaba, and we can discuss and
> > merge
> > > >>> them
> > > >>>>>>>>>> into
> > > >>>>>>>>>>>>> one,
> > > >>>>>>>>>>>>>> make it as a FLIP, and plan the tasks for
> implementation.
> > > >>> Also,
> > > >>>>>>>>> we
> > > >>>>>>>>>>>> should
> > > >>>>>>>>>>>>>> take into account the new external catalog effort in the
> > > >>> design.
> > > >>>>>>>>>> What
> > > >>>>>>>>>>>> do
> > > >>>>>>>>>>>>>> you guys think?
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> Shuyi
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 6:45 AM Jark Wu <
> imjark@xxxxxxxxx
> > >
> > > >>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>> Hi Shaoxuan,
> > > >>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>> I think summarizing it into a google doc is a good
> idea.
> > We
> > > >>>>>>>>> will
> > > >>>>>>>>>>>>> prepare
> > > >>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>> in the next few days.
> > > >>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>> Thanks,
> > > >>>>>>>>>>>>>>> Jark
> > > >>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>> Shaoxuan Wang <wshaoxuan@xxxxxxxxx> 于2018年11月28日周三
> > > >> 下午9:17写道:
> > > >>>>>>>>>>>>>>>> Hi Lin and Jark,
> > > >>>>>>>>>>>>>>>> Thanks for sharing those details. Can you please
> > consider
> > > >>>>>>>>>>>> summarizing
> > > >>>>>>>>>>>>>>> your
> > > >>>>>>>>>>>>>>>> DDL design into a google doc.
> > > >>>>>>>>>>>>>>>> We can still continue the discussions on Shuyi's
> > proposal.
> > > >>>>>>>>> But
> > > >>>>>>>>>>>>> having a
> > > >>>>>>>>>>>>>>>> separate google doc will be easy for the DEV to
> > > >>>>>>>>>>>>>>> understand/comment/discuss
> > > >>>>>>>>>>>>>>>> on your proposed DDL implementation.
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> Regards,
> > > >>>>>>>>>>>>>>>> Shaoxuan
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 7:39 PM Jark Wu <
> > imjark@xxxxxxxxx
> > > >>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> Thanks for bringing up this discussion and the
> awesome
> > > >>>>>>>>> work!
> > > >>>>>>>>>> I
> > > >>>>>>>>>>>> have
> > > >>>>>>>>>>>>>>> left
> > > >>>>>>>>>>>>>>>>> some comments in the doc.
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> I want to share something more about the watermark
> > > >>>>>>>>> definition
> > > >>>>>>>>>>>>> learned
> > > >>>>>>>>>>>>>>>> from
> > > >>>>>>>>>>>>>>>>> Alibaba.
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>       1.
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>       Table should be able to accept multiple
> watermark
> > > >>>>>>>>>>> definition.
> > > >>>>>>>>>>>>>>>>>       Because a table may have more than one rowtime
> > > >> field.
> > > >>>>>>>>> For
> > > >>>>>>>>>>>>> example,
> > > >>>>>>>>>>>>>>> one
> > > >>>>>>>>>>>>>>>>>       rowtime field is from existing field but
> missing
> > in
> > > >>> some
> > > >>>>>>>>>>>>> records,
> > > >>>>>>>>>>>>>>>>> another
> > > >>>>>>>>>>>>>>>>>       is the ingestion timestamp in Kafka but not
> very
> > > >>>>>>>>> accurate.
> > > >>>>>>>>>>> In
> > > >>>>>>>>>>>>> this
> > > >>>>>>>>>>>>>>>> case,
> > > >>>>>>>>>>>>>>>>>       user may define two rowtime fields with
> > watermarks
> > > >> in
> > > >>>>>>>>> the
> > > >>>>>>>>>>>> Table
> > > >>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>> choose
> > > >>>>>>>>>>>>>>>>>       one in different situation.
> > > >>>>>>>>>>>>>>>>>       2.
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>       Watermark stragety always work with rowtime
> field
> > > >>>>>>>>>> together.
> > > >>>>>>>>>>>>>>>>> Based on the two points metioned above, I think we
> > should
> > > >>>>>>>>>>> combine
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>> watermark strategy and rowtime field selection (i.e.
> > > >> which
> > > >>>>>>>>>>>> existing
> > > >>>>>>>>>>>>>>> field
> > > >>>>>>>>>>>>>>>>> used to generate watermark) in one clause, so that we
> > can
> > > >>>>>>>>>>> define
> > > >>>>>>>>>>>>>>> multiple
> > > >>>>>>>>>>>>>>>>> watermarks in one Table.
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> Here I will share the watermark syntax used in
> Alibaba
> > > >>>>>>>>>> (simply
> > > >>>>>>>>>>>>>>> modified):
> > > >>>>>>>>>>>>>>>>> watermarkDefinition:
> > > >>>>>>>>>>>>>>>>> WATERMARK [watermarkName] FOR <rowtime_field> AS
> > > >>>>>>>>> wm_strategy
> > > >>>>>>>>>>>>>>>>> wm_strategy:
> > > >>>>>>>>>>>>>>>>>      BOUNDED WITH OFFSET 'string' timeUnit
> > > >>>>>>>>>>>>>>>>> |
> > > >>>>>>>>>>>>>>>>>      ASCENDING
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> The “WATERMARK” keyword starts a watermark
> definition.
> > > >> The
> > > >>>>>>>>>>> “FOR”
> > > >>>>>>>>>>>>>>> keyword
> > > >>>>>>>>>>>>>>>>> defines which existing field used to generate
> > watermark,
> > > >>>>>>>>> this
> > > >>>>>>>>>>>> field
> > > >>>>>>>>>>>>>>>> should
> > > >>>>>>>>>>>>>>>>> already exist in the schema (we can use
> computed-column
> > > >> to
> > > >>>>>>>>>>> derive
> > > >>>>>>>>>>>>>> from
> > > >>>>>>>>>>>>>>>>> other fields). The “AS” keyword defines watermark
> > > >> strategy,
> > > >>>>>>>>>>> such
> > > >>>>>>>>>>>> as
> > > >>>>>>>>>>>>>>>> BOUNDED
> > > >>>>>>>>>>>>>>>>> WITH OFFSET (covers almost all the requirements) and
> > > >>>>>>>>>> ASCENDING.
> > > >>>>>>>>>>>>>>>>> When the expected rowtime field does not exist in the
> > > >>>>>>>>> schema,
> > > >>>>>>>>>>> we
> > > >>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>> use
> > > >>>>>>>>>>>>>>>>> computed-column syntax to derive it from other
> existing
> > > >>>>>>>>>> fields
> > > >>>>>>>>>>>>> using
> > > >>>>>>>>>>>>>>>>> built-in functions or user defined functions. So the
> > > >>>>>>>>>>>>>> rowtime/watermark
> > > >>>>>>>>>>>>>>>>> definition doesn’t need to care about “field-change”
> > > >>>>>>>>> strategy
> > > >>>>>>>>>>>>>>>>> (replace/add/from-field). And the proctime field
> > > >> definition
> > > >>>>>>>>>> can
> > > >>>>>>>>>>>>> also
> > > >>>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>>> defined using computed-column. Such as pt as
> PROCTIME()
> > > >>>>>>>>> which
> > > >>>>>>>>>>>>>> defines a
> > > >>>>>>>>>>>>>>>>> proctime field named “pt” in the schema.
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> Looking forward to working with you guys!
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> Best,
> > > >>>>>>>>>>>>>>>>> Jark Wu
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> Lin Li <lincoln.86xy@xxxxxxxxx> 于2018年11月28日周三
> > 下午6:33写道:
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> @Shuyi
> > > >>>>>>>>>>>>>>>>>> Thanks for the proposal!  We have a simple DDL
> > > >>>>>>>>>> implementation
> > > >>>>>>>>>>>>>>> (extends
> > > >>>>>>>>>>>>>>>>>> Calcite's parser) which been running for almost two
> > > >> years
> > > >>>>>>>>>> on
> > > >>>>>>>>>>>>>>> production
> > > >>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>> works well.
> > > >>>>>>>>>>>>>>>>>> I think the most valued things we'd learned is
> keeping
> > > >>>>>>>>>>>> simplicity
> > > >>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>> standard compliance.
> > > >>>>>>>>>>>>>>>>>> Here's the approximate grammar, FYI
> > > >>>>>>>>>>>>>>>>>> CREATE TABLE
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> CREATE TABLE tableName(
> > > >>>>>>>>>>>>>>>>>>            columnDefinition [, columnDefinition]*
> > > >>>>>>>>>>>>>>>>>>            [ computedColumnDefinition [,
> > > >>>>>>>>>>>> computedColumnDefinition]*
> > > >>>>>>>>>>>>> ]
> > > >>>>>>>>>>>>>>>>>>            [ tableConstraint [, tableConstraint]* ]
> > > >>>>>>>>>>>>>>>>>>            [ tableIndex [, tableIndex]* ]
> > > >>>>>>>>>>>>>>>>>>        [ PERIOD FOR SYSTEM_TIME ]
> > > >>>>>>>>>>>>>>>>>>            [ WATERMARK watermarkName FOR
> rowTimeColumn
> > > AS
> > > >>>>>>>>>>>>>>>>>> withOffset(rowTimeColumn, offset) ]     ) [ WITH (
> > > >>>>>>>>>>> tableOption
> > > >>>>>>>>>>>> [
> > > >>>>>>>>>>>>> ,
> > > >>>>>>>>>>>>>>>>>> tableOption]* ) ] [ ; ]
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> columnDefinition ::=
> > > >>>>>>>>>>>>>>>>>>            columnName dataType [ NOT NULL ]
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> dataType  ::=
> > > >>>>>>>>>>>>>>>>>>            {
> > > >>>>>>>>>>>>>>>>>>              [ VARCHAR ]
> > > >>>>>>>>>>>>>>>>>>              | [ BOOLEAN ]
> > > >>>>>>>>>>>>>>>>>>              | [ TINYINT ]
> > > >>>>>>>>>>>>>>>>>>              | [ SMALLINT ]
> > > >>>>>>>>>>>>>>>>>>              | [ INT ]
> > > >>>>>>>>>>>>>>>>>>              | [ BIGINT ]
> > > >>>>>>>>>>>>>>>>>>              | [ FLOAT ]
> > > >>>>>>>>>>>>>>>>>>              | [ DECIMAL ]
> > > >>>>>>>>>>>>>>>>>>              | [ DOUBLE ]
> > > >>>>>>>>>>>>>>>>>>              | [ DATE ]
> > > >>>>>>>>>>>>>>>>>>              | [ TIME ]
> > > >>>>>>>>>>>>>>>>>>              | [ TIMESTAMP ]
> > > >>>>>>>>>>>>>>>>>>              | [ VARBINARY ]
> > > >>>>>>>>>>>>>>>>>>            }
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> computedColumnDefinition ::=
> > > >>>>>>>>>>>>>>>>>>            columnName AS computedColumnExpression
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> tableConstraint ::=
> > > >>>>>>>>>>>>>>>>>>        { PRIMARY KEY | UNIQUE }
> > > >>>>>>>>>>>>>>>>>>            (columnName [, columnName]* )
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> tableIndex ::=
> > > >>>>>>>>>>>>>>>>>>            [ UNIQUE ] INDEX indexName
> > > >>>>>>>>>>>>>>>>>>             (columnName [, columnName]* )
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> rowTimeColumn ::=
> > > >>>>>>>>>>>>>>>>>>            columnName
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> tableOption ::=
> > > >>>>>>>>>>>>>>>>>>            property=value
> > > >>>>>>>>>>>>>>>>>>            offset ::=
> > > >>>>>>>>>>>>>>>>>>            positive integer (unit: ms)
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> CREATE VIEW
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> CREATE VIEW viewName
> > > >>>>>>>>>>>>>>>>>>      [
> > > >>>>>>>>>>>>>>>>>>            ( columnName [, columnName]* )
> > > >>>>>>>>>>>>>>>>>>      ]
> > > >>>>>>>>>>>>>>>>>>            AS queryStatement;
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> CREATE FUNCTION
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>     CREATE FUNCTION functionName
> > > >>>>>>>>>>>>>>>>>>      AS 'className';
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>     className ::=
> > > >>>>>>>>>>>>>>>>>>            fully qualified name
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> Shuyi Chen <suez1224@xxxxxxxxx> 于2018年11月28日周三
> > > >> 上午3:28写道:
> > > >>>>>>>>>>>>>>>>>>> Thanks a lot, Timo and Xuefu. Yes, I think we can
> > > >>>>>>>>>> finalize
> > > >>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>> design
> > > >>>>>>>>>>>>>>>>> doc
> > > >>>>>>>>>>>>>>>>>>> first and start implementation w/o the unified
> > > >>>>>>>>> connector
> > > >>>>>>>>>>> API
> > > >>>>>>>>>>>>>> ready
> > > >>>>>>>>>>>>>>> by
> > > >>>>>>>>>>>>>>>>>>> skipping some featue.
> > > >>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>> Xuefu, I like the idea of making Flink specific
> > > >>>>>>>>>> properties
> > > >>>>>>>>>>>> into
> > > >>>>>>>>>>>>>>>> generic
> > > >>>>>>>>>>>>>>>>>>> key-value pairs, so that it will make integration
> > with
> > > >>>>>>>>>> Hive
> > > >>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>> (or
> > > >>>>>>>>>>>>>>>>>> others,
> > > >>>>>>>>>>>>>>>>>>> e.g. Beam DDL) easier.
> > > >>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>> I'll run a final pass over the design doc and
> > finalize
> > > >>>>>>>>>> the
> > > >>>>>>>>>>>>> design
> > > >>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>> next few days. And we can start creating tasks and
> > > >>>>>>>>>>>> collaborate
> > > >>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>> implementation. Thanks a lot for all the comments
> and
> > > >>>>>>>>>>> inputs.
> > > >>>>>>>>>>>>>>>>>>> Cheers!
> > > >>>>>>>>>>>>>>>>>>> Shuyi
> > > >>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>> On Tue, Nov 27, 2018 at 7:02 AM Zhang, Xuefu <
> > > >>>>>>>>>>>>>>>> xuefu.z@xxxxxxxxxxxxxxx>
> > > >>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> Yeah! I agree with Timo that DDL can actually
> > proceed
> > > >>>>>>>>>> w/o
> > > >>>>>>>>>>>>> being
> > > >>>>>>>>>>>>>>>>> blocked
> > > >>>>>>>>>>>>>>>>>>> by
> > > >>>>>>>>>>>>>>>>>>>> connector API. We can leave the unknown out while
> > > >>>>>>>>>>> defining
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>> basic
> > > >>>>>>>>>>>>>>>>>>> syntax.
> > > >>>>>>>>>>>>>>>>>>>> @Shuyi
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> As commented in the doc, I think we can probably
> > > >>>>>>>>> stick
> > > >>>>>>>>>>> with
> > > >>>>>>>>>>>>>>> simple
> > > >>>>>>>>>>>>>>>>>> syntax
> > > >>>>>>>>>>>>>>>>>>>> with general properties, without extending the
> > syntax
> > > >>>>>>>>>> too
> > > >>>>>>>>>>>>> much
> > > >>>>>>>>>>>>>>> that
> > > >>>>>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>>>>>>> mimics the descriptor API.
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> Part of our effort on Flink-Hive integration is
> also
> > > >>>>>>>>> to
> > > >>>>>>>>>>>> make
> > > >>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>> syntax
> > > >>>>>>>>>>>>>>>>>>>> compatible with Hive's. The one in the current
> > > >>>>>>>>> proposal
> > > >>>>>>>>>>>> seems
> > > >>>>>>>>>>>>>>>> making
> > > >>>>>>>>>>>>>>>>>> our
> > > >>>>>>>>>>>>>>>>>>>> effort more challenging.
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> We can help and collaborate. At this moment, I
> think
> > > >>>>>>>>> we
> > > >>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>> finalize
> > > >>>>>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>>>>> the proposal and then we can divide the tasks for
> > > >>>>>>>>>> better
> > > >>>>>>>>>>>>>>>>> collaboration.
> > > >>>>>>>>>>>>>>>>>>>> Please let me know if there are  any questions or
> > > >>>>>>>>>>>>> suggestions.
> > > >>>>>>>>>>>>>>>>>>>> Thanks,
> > > >>>>>>>>>>>>>>>>>>>> Xuefu
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>
> > > >> ------------------------------------------------------------------
> > > >>>>>>>>>>>>>>>>>>>> Sender:Timo Walther <twalthr@xxxxxxxxxx>
> > > >>>>>>>>>>>>>>>>>>>> Sent at:2018 Nov 27 (Tue) 16:21
> > > >>>>>>>>>>>>>>>>>>>> Recipient:dev <dev@xxxxxxxxxxxxxxxx>
> > > >>>>>>>>>>>>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> Thanks for offering your help here, Xuefu. It
> would
> > > >>>>>>>>> be
> > > >>>>>>>>>>>> great
> > > >>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>> move
> > > >>>>>>>>>>>>>>>>>>>> these efforts forward. I agree that the DDL is
> > > >>>>>>>>> somehow
> > > >>>>>>>>>>>>> releated
> > > >>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>> unified connector API design but we can also start
> > > >>>>>>>>> with
> > > >>>>>>>>>>> the
> > > >>>>>>>>>>>>>> basic
> > > >>>>>>>>>>>>>>>>>>>> functionality now and evolve the DDL during this
> > > >>>>>>>>>> release
> > > >>>>>>>>>>>> and
> > > >>>>>>>>>>>>>> next
> > > >>>>>>>>>>>>>>>>>>> releases.
> > > >>>>>>>>>>>>>>>>>>>> For example, we could identify the MVP DDL syntax
> > > >>>>>>>>> that
> > > >>>>>>>>>>>> skips
> > > >>>>>>>>>>>>>>>> defining
> > > >>>>>>>>>>>>>>>>>>>> key constraints and maybe even time attributes.
> This
> > > >>>>>>>>>> DDL
> > > >>>>>>>>>>>>> could
> > > >>>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>>> used
> > > >>>>>>>>>>>>>>>>>>>> for batch usecases, ETL, and materializing SQL
> > > >>>>>>>>> queries
> > > >>>>>>>>>>> (no
> > > >>>>>>>>>>>>> time
> > > >>>>>>>>>>>>>>>>>>>> operations like windows).
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> The unified connector API is high on our priority
> > > >>>>>>>>> list
> > > >>>>>>>>>>> for
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>> 1.8
> > > >>>>>>>>>>>>>>>>>>>> release. I will try to update the document until
> mid
> > > >>>>>>>>> of
> > > >>>>>>>>>>>> next
> > > >>>>>>>>>>>>>>> week.
> > > >>>>>>>>>>>>>>>>>>>> Regards,
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> Timo
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> Am 27.11.18 um 08:08 schrieb Shuyi Chen:
> > > >>>>>>>>>>>>>>>>>>>>> Thanks a lot, Xuefu. I was busy for some other
> > > >>>>>>>>> stuff
> > > >>>>>>>>>>> for
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>> last 2
> > > >>>>>>>>>>>>>>>>>>>> weeks,
> > > >>>>>>>>>>>>>>>>>>>>> but we are definitely interested in moving this
> > > >>>>>>>>>>> forward.
> > > >>>>>>>>>>>> I
> > > >>>>>>>>>>>>>>> think
> > > >>>>>>>>>>>>>>>>> once
> > > >>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>> unified connector API design [1] is done, we can
> > > >>>>>>>>>>> finalize
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>>>> design
> > > >>>>>>>>>>>>>>>>>>>> as
> > > >>>>>>>>>>>>>>>>>>>>> well and start creating concrete subtasks to
> > > >>>>>>>>>>> collaborate
> > > >>>>>>>>>>>> on
> > > >>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>> implementation with the community.
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> Shuyi
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> [1]
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
> > > >>>>>>>>>>>>>>>>>>>>> On Mon, Nov 26, 2018 at 7:01 PM Zhang, Xuefu <
> > > >>>>>>>>>>>>>>>>>> xuefu.z@xxxxxxxxxxxxxxx>
> > > >>>>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> I'm wondering if you folks still have the
> > > >>>>>>>>> bandwidth
> > > >>>>>>>>>>>>> working
> > > >>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>> this.
> > > >>>>>>>>>>>>>>>>>>>>>> We have some dedicated resource and like to move
> > > >>>>>>>>>> this
> > > >>>>>>>>>>>>>> forward.
> > > >>>>>>>>>>>>>>>> We
> > > >>>>>>>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>>>>>>>> collaborate.
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> Thanks,
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> Xuefu
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>> ------------------------------------------------------------------
> > > >>>>>>>>>>>>>>>>>>>>>> 发件人:wenlong.lwl<wenlong88.lwl@xxxxxxxxx>
> > > >>>>>>>>>>>>>>>>>>>>>> 日 期:2018年11月05日 11:15:35
> > > >>>>>>>>>>>>>>>>>>>>>> 收件人:<dev@xxxxxxxxxxxxxxxx>
> > > >>>>>>>>>>>>>>>>>>>>>> 主 题:Re: [DISCUSS] Flink SQL DDL Design
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> Hi, Shuyi, thanks for the proposal.
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> I have two concerns about the table ddl:
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> 1. how about remove the source/sink mark from
> the
> > > >>>>>>>>>> ddl,
> > > >>>>>>>>>>>>>> because
> > > >>>>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>>>> is
> > > >>>>>>>>>>>>>>>>>>> not
> > > >>>>>>>>>>>>>>>>>>>>>> necessary, the framework determine the table
> > > >>>>>>>>>> referred
> > > >>>>>>>>>>>> is a
> > > >>>>>>>>>>>>>>>> source
> > > >>>>>>>>>>>>>>>>>> or a
> > > >>>>>>>>>>>>>>>>>>>> sink
> > > >>>>>>>>>>>>>>>>>>>>>> according to the context of the query using the
> > > >>>>>>>>>> table.
> > > >>>>>>>>>>>> it
> > > >>>>>>>>>>>>>> will
> > > >>>>>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>>>> more
> > > >>>>>>>>>>>>>>>>>>>>>> convenient for use defining a table which can be
> > > >>>>>>>>>> both
> > > >>>>>>>>>>> a
> > > >>>>>>>>>>>>>> source
> > > >>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>> sink,
> > > >>>>>>>>>>>>>>>>>>>>>> and more convenient for catalog to persistent
> and
> > > >>>>>>>>>>> manage
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>> meta
> > > >>>>>>>>>>>>>>>>>>> infos.
> > > >>>>>>>>>>>>>>>>>>>>>> 2. how about just keeping one pure string map as
> > > >>>>>>>>>>>>> parameters
> > > >>>>>>>>>>>>>>> for
> > > >>>>>>>>>>>>>>>>>> table,
> > > >>>>>>>>>>>>>>>>>>>> like
> > > >>>>>>>>>>>>>>>>>>>>>> create tabe Kafka10SourceTable (
> > > >>>>>>>>>>>>>>>>>>>>>> intField INTEGER,
> > > >>>>>>>>>>>>>>>>>>>>>> stringField VARCHAR(128),
> > > >>>>>>>>>>>>>>>>>>>>>> longField BIGINT,
> > > >>>>>>>>>>>>>>>>>>>>>> rowTimeField TIMESTAMP
> > > >>>>>>>>>>>>>>>>>>>>>> ) with (
> > > >>>>>>>>>>>>>>>>>>>>>> connector.type = ’kafka’,
> > > >>>>>>>>>>>>>>>>>>>>>> connector.property-version = ’1’,
> > > >>>>>>>>>>>>>>>>>>>>>> connector.version = ’0.10’,
> > > >>>>>>>>>>>>>>>>>>>>>> connector.properties.topic = ‘test-kafka-topic’,
> > > >>>>>>>>>>>>>>>>>>>>>> connector.properties.startup-mode =
> > > >>>>>>>>> ‘latest-offset’,
> > > >>>>>>>>>>>>>>>>>>>>>> connector.properties.specific-offset = ‘offset’,
> > > >>>>>>>>>>>>>>>>>>>>>> format.type = 'json'
> > > >>>>>>>>>>>>>>>>>>>>>> format.prperties.version=’1’,
> > > >>>>>>>>>>>>>>>>>>>>>> format.derive-schema = 'true'
> > > >>>>>>>>>>>>>>>>>>>>>> );
> > > >>>>>>>>>>>>>>>>>>>>>> Because:
> > > >>>>>>>>>>>>>>>>>>>>>> 1. in TableFactory, what user use is a string
> map
> > > >>>>>>>>>>>>>> properties,
> > > >>>>>>>>>>>>>>>>>> defining
> > > >>>>>>>>>>>>>>>>>>>>>> parameters by string-map can be the closest way
> to
> > > >>>>>>>>>>>> mapping
> > > >>>>>>>>>>>>>> how
> > > >>>>>>>>>>>>>>>>> user
> > > >>>>>>>>>>>>>>>>>>> use
> > > >>>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>> parameters.
> > > >>>>>>>>>>>>>>>>>>>>>> 2. The table descriptor can be extended by user,
> > > >>>>>>>>>> like
> > > >>>>>>>>>>>> what
> > > >>>>>>>>>>>>>> is
> > > >>>>>>>>>>>>>>>> done
> > > >>>>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>>> Kafka
> > > >>>>>>>>>>>>>>>>>>>>>> and Json, it means that the parameter keys in
> > > >>>>>>>>>>> connector
> > > >>>>>>>>>>>> or
> > > >>>>>>>>>>>>>>>> format
> > > >>>>>>>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>>>>>>>> different in different implementation, we can
> not
> > > >>>>>>>>>>>> restrict
> > > >>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>> key
> > > >>>>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>> a
> > > >>>>>>>>>>>>>>>>>>>>>> specified set, so we need a map in connector
> scope
> > > >>>>>>>>>>> and a
> > > >>>>>>>>>>>>> map
> > > >>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>>>>> connector.properties scope. why not just give
> > > >>>>>>>>> user a
> > > >>>>>>>>>>>>> single
> > > >>>>>>>>>>>>>>> map,
> > > >>>>>>>>>>>>>>>>> let
> > > >>>>>>>>>>>>>>>>>>>> them
> > > >>>>>>>>>>>>>>>>>>>>>> put parameters in a format they like, which is
> > > >>>>>>>>> also
> > > >>>>>>>>>>> the
> > > >>>>>>>>>>>>>>> simplest
> > > >>>>>>>>>>>>>>>>> way
> > > >>>>>>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>>>>>>> implement DDL parser.
> > > >>>>>>>>>>>>>>>>>>>>>> 3. whether we can define a format clause or not,
> > > >>>>>>>>>>> depends
> > > >>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>> implementation of the connector, using different
> > > >>>>>>>>>>> clause
> > > >>>>>>>>>>>> in
> > > >>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>> may
> > > >>>>>>>>>>>>>>>>>>> make
> > > >>>>>>>>>>>>>>>>>>>> a
> > > >>>>>>>>>>>>>>>>>>>>>> misunderstanding that we can combine the
> > > >>>>>>>>> connectors
> > > >>>>>>>>>>> with
> > > >>>>>>>>>>>>>>>> arbitrary
> > > >>>>>>>>>>>>>>>>>>>> formats,
> > > >>>>>>>>>>>>>>>>>>>>>> which may not work actually.
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> On Sun, 4 Nov 2018 at 18:25, Dominik Wosiński <
> > > >>>>>>>>>>>>>>> wossyn@xxxxxxxxx
> > > >>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>>> +1, Thanks for the proposal.
> > > >>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>> I guess this is a long-awaited change. This can
> > > >>>>>>>>>>> vastly
> > > >>>>>>>>>>>>>>> increase
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>> functionalities of the SQL Client as it will be
> > > >>>>>>>>>>>> possible
> > > >>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>> use
> > > >>>>>>>>>>>>>>>>>>> complex
> > > >>>>>>>>>>>>>>>>>>>>>>> extensions like for example those provided by
> > > >>>>>>>>>> Apache
> > > >>>>>>>>>>>>>>> Bahir[1].
> > > >>>>>>>>>>>>>>>>>>>>>>> Best Regards,
> > > >>>>>>>>>>>>>>>>>>>>>>> Dom.
> > > >>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>> [1]
> > > >>>>>>>>>>>>>>>>>>>>>>> https://github.com/apache/bahir-flink
> > > >>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>> sob., 3 lis 2018 o 17:17 Rong Rong <
> > > >>>>>>>>>>>> walterddr@xxxxxxxxx>
> > > >>>>>>>>>>>>>>>>>> napisał(a):
> > > >>>>>>>>>>>>>>>>>>>>>>>> +1. Thanks for putting the proposal together
> > > >>>>>>>>>> Shuyi.
> > > >>>>>>>>>>>>>>>>>>>>>>>> DDL has been brought up in a couple of times
> > > >>>>>>>>>>>> previously
> > > >>>>>>>>>>>>>>> [1,2].
> > > >>>>>>>>>>>>>>>>>>>>>> Utilizing
> > > >>>>>>>>>>>>>>>>>>>>>>>> DDL will definitely be a great extension to
> the
> > > >>>>>>>>>>>> current
> > > >>>>>>>>>>>>>>> Flink
> > > >>>>>>>>>>>>>>>>> SQL
> > > >>>>>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>>>>>>>>> systematically support some of the previously
> > > >>>>>>>>>>> brought
> > > >>>>>>>>>>>> up
> > > >>>>>>>>>>>>>>>>> features
> > > >>>>>>>>>>>>>>>>>>> such
> > > >>>>>>>>>>>>>>>>>>>>>> as
> > > >>>>>>>>>>>>>>>>>>>>>>>> [3]. And it will also be beneficial to see the
> > > >>>>>>>>>>>> document
> > > >>>>>>>>>>>>>>>> closely
> > > >>>>>>>>>>>>>>>>>>>> aligned
> > > >>>>>>>>>>>>>>>>>>>>>>>> with the previous discussion for unified SQL
> > > >>>>>>>>>>> connector
> > > >>>>>>>>>>>>> API
> > > >>>>>>>>>>>>>>>> [4].
> > > >>>>>>>>>>>>>>>>>>>>>>>> I also left a few comments on the doc. Looking
> > > >>>>>>>>>>> forward
> > > >>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>> alignment
> > > >>>>>>>>>>>>>>>>>>>>>>>> with the other couple of efforts and
> > > >>>>>>>>> contributing
> > > >>>>>>>>>> to
> > > >>>>>>>>>>>>> them!
> > > >>>>>>>>>>>>>>>>>>>>>>>> Best,
> > > >>>>>>>>>>>>>>>>>>>>>>>> Rong
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> [1]
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201805.mbox/%3CCAMZk55ZTJA7MkCK1Qu4gLPu1P9neqCfHZtTcgLfrFjfO4Xv5YQ%40mail.gmail.com%3E
> > > >>>>>>>>>>>>>>>>>>>>>>>> [2]
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3CDC070534-0782-4AFD-8A85-8A82B384B8F7%40gmail.com%3E
> > > >>>>>>>>>>>>>>>>>>>>>>>> [3]
> > > >>>>>>>>>>> https://issues.apache.org/jira/browse/FLINK-8003
> > > >>>>>>>>>>>>>>>>>>>>>>>> [4]
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3C6676cb66-6f31-23e1-eff5-2e9c19f88483@xxxxxxxxxx%3E
> > > >>>>>>>>>>>>>>>>>>>>>>>> On Fri, Nov 2, 2018 at 10:22 AM Bowen Li <
> > > >>>>>>>>>>>>>>> bowenli86@xxxxxxxxx
> > > >>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>>>>> Thanks Shuyi!
> > > >>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>> I left some comments there. I think the
> design
> > > >>>>>>>>> of
> > > >>>>>>>>>>> SQL
> > > >>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>>> Flink-Hive
> > > >>>>>>>>>>>>>>>>>>>>>>>>> integration/External catalog enhancements
> will
> > > >>>>>>>>>> work
> > > >>>>>>>>>>>>>> closely
> > > >>>>>>>>>>>>>>>>> with
> > > >>>>>>>>>>>>>>>>>>> each
> > > >>>>>>>>>>>>>>>>>>>>>>>>> other. Hope we are well aligned on the
> > > >>>>>>>>> directions
> > > >>>>>>>>>>> of
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>> two
> > > >>>>>>>>>>>>>>>>>>> designs,
> > > >>>>>>>>>>>>>>>>>>>>>>>> and I
> > > >>>>>>>>>>>>>>>>>>>>>>>>> look forward to working with you guys on
> both!
> > > >>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>> Bowen
> > > >>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>> On Thu, Nov 1, 2018 at 10:57 PM Shuyi Chen <
> > > >>>>>>>>>>>>>>>> suez1224@xxxxxxxxx
> > > >>>>>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Hi everyone,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> SQL DDL support has been a long-time ask
> from
> > > >>>>>>>>>> the
> > > >>>>>>>>>>>>>>> community.
> > > >>>>>>>>>>>>>>>>>>>>>> Current
> > > >>>>>>>>>>>>>>>>>>>>>>>>> Flink
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> SQL support only DML (e.g. SELECT and INSERT
> > > >>>>>>>>>>>>>> statements).
> > > >>>>>>>>>>>>>>> In
> > > >>>>>>>>>>>>>>>>> its
> > > >>>>>>>>>>>>>>>>>>>>>>>> current
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> form, Flink SQL users still need to
> > > >>>>>>>>>> define/create
> > > >>>>>>>>>>>>> table
> > > >>>>>>>>>>>>>>>>> sources
> > > >>>>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>>>> sinks
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> programmatically in Java/Scala. Also, in SQL
> > > >>>>>>>>>>> Client,
> > > >>>>>>>>>>>>>>> without
> > > >>>>>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>>>>>>>>> support,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> the current implementation does not allow
> > > >>>>>>>>>>> dynamical
> > > >>>>>>>>>>>>>>> creation
> > > >>>>>>>>>>>>>>>>> of
> > > >>>>>>>>>>>>>>>>>>>>>>> table,
> > > >>>>>>>>>>>>>>>>>>>>>>>>> type
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> or functions with SQL, this adds friction
> for
> > > >>>>>>>>>> its
> > > >>>>>>>>>>>>>>> adoption.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> I drafted a design doc [1] with a few other
> > > >>>>>>>>>>>> community
> > > >>>>>>>>>>>>>>>> members
> > > >>>>>>>>>>>>>>>>>> that
> > > >>>>>>>>>>>>>>>>>>>>>>>>> proposes
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> the design and implementation for adding DDL
> > > >>>>>>>>>>> support
> > > >>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>> Flink.
> > > >>>>>>>>>>>>>>>>>> The
> > > >>>>>>>>>>>>>>>>>>>>>>>>> initial
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> design considers DDL for table, view, type,
> > > >>>>>>>>>>> library
> > > >>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>> function.
> > > >>>>>>>>>>>>>>>>>>>>>> It
> > > >>>>>>>>>>>>>>>>>>>>>>>> will
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> be great to get feedback on the design from
> > > >>>>>>>>> the
> > > >>>>>>>>>>>>>> community,
> > > >>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>> align
> > > >>>>>>>>>>>>>>>>>>>>>>>> with
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> latest effort in unified SQL connector API
> [2]
> > > >>>>>>>>>> and
> > > >>>>>>>>>>>>> Flink
> > > >>>>>>>>>>>>>>>> Hive
> > > >>>>>>>>>>>>>>>>>>>>>>>>> integration
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> [3].
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Any feedback is highly appreciated.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Thanks
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi Chen
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit?usp=sharing
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> [2]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> [3]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1SkppRD_rE3uOKSN-LuZCqn4f7dz0zW5aa6T_hBZq5_o/edit?usp=sharing
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> --
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will
> > > >>>>>>>>> somehow
> > > >>>>>>>>>>>>> connect
> > > >>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>> your
> > > >>>>>>>>>>>>>>>>>>>>>>>> future."
> > > >>>>>>>>>>>>>>>>>>> --
> > > >>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will somehow
> > > >>>>>>>>> connect
> > > >>>>>>>>>> in
> > > >>>>>>>>>>>>> your
> > > >>>>>>>>>>>>>>>>> future."
> > > >>>>>>>>>>>>>> --
> > > >>>>>>>>>>>>>> "So you have to trust that the dots will somehow connect
> > in
> > > >>> your
> > > >>>>>>>>>>>> future."
> > > >>>>>>>>> --
> > > >>>>>>>>> "So you have to trust that the dots will somehow connect in
> > your
> > > >>>>>>> future."
> > > >>>>>>>
> > > >>>>
> > >
> > >
> >
> > --
> > "So you have to trust that the dots will somehow connect in your future."
> >
>