+1, I think this can make the grammar more clear. Please remember to add a release note once the issue is finished.
Best, Jark On Thu, 1 Jun 2023 at 11:28, yuxia <luoyu...@alumni.sjtu.edu.cn> wrote: > Hi, Jingsong. It's hard to provide an option regarding to the fact that we > also want to decouple Hive with flink planner. > If we still need this fall back behavior, we will still depend on > `ParserImpl` provided by flink-table-planner on HiveParser. > But to try best to minimize the impact to users and more user-friendly, > I'll remind users may use set table.sql-dialect = default to switch to > Flink's default dialect in error message when fail to parse the sql in > HiveParser. > > Best regards, > Yuxia > > Best regards, > Yuxia > > ----- 原始邮件 ----- > 发件人: "Jingsong Li" <jingsongl...@gmail.com> > 收件人: "Rui Li" <lirui.fu...@gmail.com> > 抄送: "dev" <d...@flink.apache.org>, "yuxia" <luoyu...@alumni.sjtu.edu.cn>, > "User" <user@flink.apache.org> > 发送时间: 星期二, 2023年 5 月 30日 下午 3:21:56 > 主题: Re: [DISCUSS] Hive dialect shouldn't fall back to Flink's default > dialect > > +1, the fallback looks weird now, it is outdated. > > But, it is good to provide an option. I don't know if there are some > users who depend on this fallback. > > Best, > Jingsong > > On Tue, May 30, 2023 at 1:47 PM Rui Li <lirui.fu...@gmail.com> wrote: > > > > +1, the fallback was just intended as a temporary workaround to run > catalog/module related statements with hive dialect. > > > > On Mon, May 29, 2023 at 3:59 PM Benchao Li <libenc...@apache.org> wrote: > >> > >> Big +1 on this, thanks yuxia for driving this! > >> > >> yuxia <luoyu...@alumni.sjtu.edu.cn> 于2023年5月29日周一 14:55写道： > >> > >> > Hi, community. > >> > > >> > I want to start the discussion about Hive dialect shouldn't fall back > to > >> > Flink's default dialect. > >> > > >> > Currently, when the HiveParser fail to parse the sql in Hive dialect, > >> > it'll fall back to Flink's default parser[1] to handle flink-specific > >> > statements like "CREATE CATALOG xx with (xx);". > >> > > >> > As I‘m involving with Hive dialect and have some communication with > >> > community users who use Hive dialectrecently, I'm thinking throw > exception > >> > directly instead of falling back to Flink's default dialect when fail > to > >> > parse the sql in Hive dialect > >> > > >> > Here're some reasons: > >> > > >> > First of all, it'll hide some error with Hive dialect. For example, we > >> > found we can't use Hive dialect any more with Flink sql client in > release > >> > validation phase[2], finally we find a modification in Flink sql > client > >> > cause it, but our test case can't find it earlier for although > HiveParser > >> > faill to parse it but then it'll fall back to default parser and pass > test > >> > case successfully. > >> > > >> > Second, conceptually, Hive dialect should be do nothing with Flink's > >> > default dialect. They are two totally different dialect. If we do > need a > >> > dialect mixing Hive dialect and default dialect , may be we need to > propose > >> > a new hybrid dialect and announce the hybrid behavior to users. > >> > Also, It made some users confused for the fallback behavior. The fact > >> > comes from I had been ask by community users. Throw an excpetioin > directly > >> > when fail to parse the sql statement in Hive dialect will be more > intuitive. > >> > > >> > Last but not least, it's import to decouple Hive with Flink planner[3] > >> > before we can externalize Hive connector[4]. If we still fall back to > Flink > >> > default dialct, then we will need depend on `ParserImpl` in Flink > planner, > >> > which will block us removing the provided dependency of Hive dialect > as > >> > well as externalizing Hive connector. > >> > > >> > Although we hadn't announced the fall back behavior ever, but some > users > >> > may implicitly depend on this behavior in theirs sql jobs. So, I > hereby > >> > open the dicussion about abandoning the fall back behavior to make > Hive > >> > dialect clear and isoloted. > >> > Please remember it won't break the Hive synatax but the syntax > specified > >> > to Flink may fail after then. But for the failed sql, you can use `SET > >> > table.sql-dialect=default;` to switch to Flink dialect. > >> > If there's some flink-specific statements we found should be included > in > >> > Hive dialect to be easy to use, I think we can still add them as > specific > >> > cases to Hive dialect. > >> > > >> > Look forwards to your feedback. I'd love to listen the feedback from > >> > community to take the next steps. > >> > > >> > [1]: > >> > > https://github.com/apache/flink/blob/678370b18e1b6c4a23e5ce08f8efd05675a0cc17/flink-connectors/flink-connector-hive/src/main/java/org/apache/flink/table/planner/delegation/hive/HiveParser.java#L348 > >> > [2]:https://issues.apache.org/jira/browse/FLINK-26681 > >> > [3]:https://issues.apache.org/jira/browse/FLINK-31413 > >> > [4]:https://issues.apache.org/jira/browse/FLINK-30064 > >> > > >> > > >> > > >> > Best regards, > >> > Yuxia > >> > > >> > >> > >> -- > >> > >> Best, > >> Benchao Li > > > > > > > > -- > > Best regards! > > Rui Li >
