Hi kui Thanks for your answer and +1 to yuxia too
> we should not bind the watermark-related options to a connector to ensure semantic clarity. In my opinion, adding watermark-related options to a connector is much more clear. Currently users can define simple watermark strategy in DDL, adding more configuration items in connector options is easy to understand Best, Shammon On Thu, Feb 23, 2023 at 10:52 AM Jingsong Li <jingsongl...@gmail.com> wrote: > Thanks for your proposal. > > +1 to yuxia, consider watermark-related hints as option hints. > > Personally, I am cautious about adding SQL syntax, WATERMARK_PARAMS is > also SQL syntax to some extent. > > We can use OPTIONS to meet this requirement if possible. > > Best, > Jingsong > > On Thu, Feb 23, 2023 at 10:41 AM yuxia <luoyu...@alumni.sjtu.edu.cn> > wrote: > > > > Hi, Yuan Kui. > > Thanks for driving it. > > IMO, the 'OPTIONS' hint may be not only specific to the connector > options. Just as a reference, we also have `sink.parallelism`[1] as a > connector options. It enables > > user to specific the writer's parallelism dynamically per-query. > > > > Personally, I perfer to consider watermark-related hints as option > hints. So, user can define a default watermark strategy for the table, and > if user dosen't needed to changes it, they need to do nothing in their > query instead of specific it ervery time. > > > > [1] > https://nightlies.apache.org/flink/flink-docs-master/zh/docs/connectors/table/filesystem/#sink-parallelism > > > > Best regards, > > Yuxia > > > > Best regards, > > Yuxia > > > > ----- 原始邮件 ----- > > 发件人: "kui yuan" <catye...@gmail.com> > > 收件人: "dev" <dev@flink.apache.org> > > 抄送: "Jark Wu" <imj...@gmail.com> > > 发送时间: 星期三, 2023年 2 月 22日 下午 10:08:11 > > 主题: Re: [DISCUSS] FLIP-296: Watermark options for table API & SQL > > > > Hi all, > > > > Thanks for the lively discussion and I will respond to these questions > one > > by one. However, there are also some common questions and I will answer > > together. > > > > @郑 Thanks for your reply. The features mentioned in this flip are only > for > > those source connectors that implement the SupportsWatermarkPushDown > > interface, generating watermarks in other graph locations is not in the > > scope of this discussion. Perhaps another flip can be proposed later to > > implement this feature. > > > > @Shammon Thanks for your reply. In Flip-296, a rejected alternative is > > adding watermark related options in the connector options，we believe that > > we should not bind the watermark-related options to a connector to ensure > > semantic clarity. > > > > > What will happen if we add watermark related options in `the connector > > > options`? Will the connector ignore these options or throw an > exception? > > > How can we support this? > > > > If user defines different watermark configurations for one table in two > > places, I tend to prefer the first place would prevail, but we can also > > throw exception or just print logs to prompt the user, which are > > implementation details. > > > > > If one table is used by two operators with different watermark params, > > > what will happen? > > > > @Martijn Thanks for your reply. I'm sorry that we are not particularly > > accurate, this hint is mainly for SQL, not table API. > > > > > While the FLIP talks about watermark options for Table API & SQL, I > only > > > see proposed syntax for SQL, not for the Table API. What is your > proposal > > > for the Table API > > > > @Jane Thanks for your reply. For the first question, If the user uses > this > > hint on those sourse that does not implement the > SupportsWatermarkPushDown > > interface, it will be completely invalid. The task will run as normal as > if > > the hint had not been used. > > > > > What's the behavior if there are multiple table sources, among which > > > some do not support `SupportsWatermarkPushDown`? > > > > @Jane feedback that 'WATERMARK_PARAMS' is difficult to remember, perhaps > > the naming issue can be put to the end of the discussion, because more > > people like @Martijn @Shuo are considering whether these configurations > > should be put into the DDL or the 'OPTIONS' hint. Here's what I > > think, Putting these configs into DDL or putting them into 'OPTIONS' hint > > is actually the same thing, because the 'OPTIONS' hint is mainly used to > > configure the properties of conenctor. The reason why I want to use a new > > hint is to make sure the semantics clear, in my opinion the configuration > > of watermark should not be mixed up with connector. However, a new hint > > does make it more difficult to use to some extent, for example, when a > user > > uses both 'OPTIONS' hint and 'WATERMARK_PARAMS' hint. For this point, > maby > > it is more appropriate to use uniform 'OPTIONS' hint. > > On the other hand, if we enrich more watermark option keys in 'OPTIONS' > > hints, The question will be what we treat the definatrions of 'OPTIONS' > > hint, is this only specific to the connector options or could be more? > > Maybe @Jark could share more insights here. In my opion, 'OPTIONS' is > only > > related to the connector options, which is not like the gernal watermark > > options. > > > > > > > > Shuo Cheng <njucs...@gmail.com> 于2023年2月22日周三 19:17写道： > > > > > Hi Kui, > > > > > > Thanks for driving the discussion. It's quite useful to introduce > Watermark > > > options. I have some questions: > > > > > > What kind of hints is "WATERMARK_PARAMS"? > > > Currently, we have two kinds of hints in Flink: Dynamic Table Options & > > > Query Hints. As described in the Flip, "WATERMARK_PARAMS" is more like > > > Dynamic Table Options. So two questions arise here: > > > > > > 1) Are these watermark options to be exposed as connector WITH > options? Aa > > > described in SQL Hints doc[1], "Dynamic Table Options allow to > specify or > > > override table options dynamically", which implies that these options > can > > > also be configured in WITH options. > > > > > > 2) Do we really need a new hint name like 'WATERMARK_PARAMS', table > > > options use "OPTIONS" as hint name, like '/*+ > > > OPTIONS('csv.ignore-parse-errors'='true') */', maybe we can enrich more > > > table option keys for watermark, e.g., /*+ > > > OPTIONS('watermark.emit-strategy'='ON_PERIODIC') */. > > > > > > > > > [1] > > > > > > > https://nightlies.apache.org/flink/flink-docs-release-1.16/docs/dev/table/sql/queries/hints/ > > > > > > On Wed, Feb 22, 2023 at 10:22 AM kui yuan <catye...@gmail.com> wrote: > > > > > > > Hi devs, > > > > > > > > > > > > I'd like to start a discussion thread for FLIP-296[1]. This comes > from an > > > > offline discussion with @Yun Tang, and we hope to enrich table API & > SQL > > > to > > > > support many watermark-related features which were only implemented > at > > > the > > > > datastream API level. > > > > > > > > > > > > Basically, we want to introduce watermark options in table API & SQL > via > > > > SQL hint named 'WATERMARK_PARAMS' to support features: > > > > > > > > 1、Configurable watermark emit strategy > > > > > > > > 2、Dealing with idle sources > > > > > > > > 3、Watermark alignment > > > > > > > > > > > > Last but not least, thanks to Qingsheng and Jing Zhang for the > initial > > > > reviews. > > > > > > > > > > > > Looking forward to your thoughts and any feedback is appreciated! > > > > > > > > > > > > [1] > > > > > > > > https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=240884405 > > > > > > > > > > > > Best > > > > > > > > Yuan Kui > > > > > > > >
