Thanks Konstantin, Regarding your questions, hope my comments has address your questions and I also add a few explanation in the FLIP.
Thank you all for the feedback, It seems everyone involved in this thread has reached a consensus. I will start a vote thread later. Best, Leonard > 在 2020年8月3日，19:35，godfrey he <godfre...@gmail.com> 写道： > > Thanks Lennard for driving this FLIP. > Looks good to me. > > Best, > Godfrey > > Jark Wu <imj...@gmail.com> 于2020年8月3日周一 下午12:04写道： > >> Thanks Leonard for the great FLIP. I think it is in very good shape. >> +1 to start a vote. >> >> Best, >> Jark >> >> On Fri, 31 Jul 2020 at 17:56, Fabian Hueske <fhue...@gmail.com> wrote: >> >>> Hi Leonard, >>> >>> Thanks for this FLIP! >>> Looks good from my side. >>> >>> Cheers, Fabian >>> >>> Am Do., 30. Juli 2020 um 22:15 Uhr schrieb Seth Wiesman < >>> sjwies...@gmail.com >>>> : >>> >>>> Hi Leondard, >>>> >>>> Thank you for pushing this, I think the updated syntax looks really >> good >>>> and the semantics make sense to me. >>>> >>>> +1 >>>> >>>> Seth >>>> >>>> On Wed, Jul 29, 2020 at 11:36 AM Leonard Xu <xbjt...@gmail.com> wrote: >>>> >>>>> Hi, Konstantin >>>>> >>>>>> >>>>>> 1) A "Versioned Temporal Table DDL on source" can only be joined >> on >>>> the >>>>>> PRIMARY KEY attribute, correct? >>>>> Yes, the PRIMARY KEY would be join key. >>>>> >>>>>> >>>>>> 2) Isn't it the time attribute in the ORDER BY clause of the VIEW >>>>> definition that defines >>>>>> whether a event-time or processing time temporal table join is >> used? >>>>> >>>>> I think event-time or processing-time temporal table join depends on >>> fact >>>>> table’s time attribute in temporal join rather than from temporal >> table >>>>> side, the event-time or processing time in temporal table is just >> used >>> to >>>>> split the validity period of versioned snapshot of temporal table. >> The >>>>> processing time attribute is not necessary for temporal table >> without >>>>> version, only the primary key is required, the following VIEW is also >>>> valid >>>>> for temporal table without version. >>>>> CREATE VIEW latest_rates AS >>>>> SELECT currency, LAST_VALUE(rate) -- only keep the latest >>>>> version >>>>> FROM rates >>>>> GROUP BY currency; -- inferred primary key >>>>> >>>>> >>>>>> >>>>>> 3) A "Versioned Temporal Table DDL on source" is always versioned >> on >>>>>> operation_time regardless of the lookup table attribute (event-time >>> or >>>>>> processing time attribute), correct? >>>>> >>>>> >>>>> Yes, the semantics of `FOR SYSTEM_TIME AS OF o.time` is using the >>> o.time >>>>> value to lookup the version of the temporal table. >>>>> For fact table has the processing time attribute, it means only >> lookup >>>> the >>>>> latest version of temporal table and we can do some optimization in >>>>> implementation like only keep the latest version. >>>>> >>>>> >>>>> Best >>>>> Leonard >>>> >>> >>
