Hi, Could someone who is familiar with JDBC explain the behavior of cancel/close for UPDATE/INSERT case?
If we can't find any useful use-case for providing both of cancel and close, we'll provide only cancel in this proposal. If we find an useful use-case for it, we can add close later. Thanks, -- kou In <d2aa40f7-ce43-3121-0946-f33ee0d30...@python.org> "Re: [DISCUSS][Format][Flight] Result set expiration support" on Wed, 21 Jun 2023 15:53:54 +0200, Antoine Pitrou <anto...@python.org> wrote: > > Ah... in JDBC, if the statement is something like an UPDATE or INSERT, > than cancelling the statement is not the same thing as closing the > result set? The latter would probably just discard the result set but > still commit the results? > > The problem is that Flight RPC doesn't have separate notions of > queries and results sets... > > > Le 21/06/2023 à 15:49, David Li a écrit : >> There is a PR linked in the original message, but here it is again: >> https://github.com/apache/arrow/pull/36009 >> Cancel and Close are close semantically, but Cancel is meant for when >> the (client thinks that) computation is still ongoing, while Close is >> meant to free server resources after reading a result set. (For >> example, JDBC has Statement#cancel [1] and ResultSet#close [2].) >> That said, I think it's reasonable to only have Cancel at the protocol >> level. >> [1]: >> https://docs.oracle.com/javase/8/docs/api/java/sql/Statement.html#cancel-- >> [2]: >> https://docs.oracle.com/javase/8/docs/api/java/sql/ResultSet.html#close-- >> On Wed, Jun 21, 2023, at 09:35, Antoine Pitrou wrote: >>> Hi Kou, >>> >>> Can we have an actual PR with the proposed gRPC field, method and >>> docstring additions? >>> >>> Regardless, I have some comments and questions: >>> >>> * "RefreshFlightEndpoint" suggests the server will recompute (refresh) >>> the results; instead I would suggest "PersistFlightEndpoint" >>> >>> * Perhaps "PersistFlightEndpoint" can take an optional >>> "suggested_expiration" timestamp, which the server is free to ignore >>> (some clients may only need to extend the expiration by two minutes, >>> others by two days...) >>> >>> * Does the client potentially have to call "PersistFlightEndpoint" on >>> each returned endpoint? Can it pass several endpoints at once? >>> >>> * What is the expected difference between "CancelFlightInfo" and >>> "CloseFlightInfo"? Both seem to have a similar effect, and the exact >>> behaviour will probably be server-dependent anyway ("cancel" and >>> "close" >>> may have meaningful differences when putting/uploading data, not so >>> much >>> when getting/downloading data, IMHO?). >>> >>> Regards >>> >>> Antoine. >>> >>> >>> >>> Le 21/06/2023 à 02:28, Sutou Kouhei a écrit : >>>> Hi, >>>> >>>> David provided the Java implementation. Thanks! >>>> >>>> If anyone has any comments about this proposal, please share >>>> them. >>>> >>>> >>>> Thanks,
