+1, thanks yuxia for driving the hive decoupling work! Since the 1.16 release, the compatibility of Hive queries has reached a relatively high level, so it is time to abandon the internal fallback, which will make the behavior of the Hive dialect clearer.
Best, Lincoln Lee Jark Wu <imj...@gmail.com> 于2023年6月1日周四 21:23写道： > +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" <dev@flink.apache.org>, "yuxia" <luoyu...@alumni.sjtu.edu.cn>, > > "User" <u...@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 +1, the fallback looks weird now, it is outdated.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 > > >
