Hi Lincoln, Thank you for your feedback.
I guess we already have similar behavior for CTAS, where we could put more columns than we have for query. In this case these extra columns should be filled with nulls, and the query should be rewritten accordingly [1]. This also means that extra columns should have nullable type (there is a dedicated validation for this). It means that for non query columns we have such default values and query is rewritten taking them into account Regarding adding columns with alter, or some other changes like adding/dropping columns, constraints, distribution if I understand correctly MaterializedTableManager looking at table change can decide whether it should recompute materialized table or not Would it make sense? [1] https://github.com/apache/flink/blob/3478ddf08bce49e271f69b922a37ccada6f58688/flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/operations/converters/table/SqlCreateTableAsConverter.java#L66-L74 On Tue, Oct 7, 2025 at 4:14 AM Lincoln Lee <[email protected]> wrote: > > Thanks Sergey for driving this FLIP, it's a great addition to materialized > table! > > Since it coincided with China's National Day holiday and everyone is still > on > vacation, we couldn't reply promptly. > > I haven't fully reviewed all the content in the FLIP yet, but there's an > important issue on the ALTER statement: > > Unlike a regular CREATE TABLE, Materialized Table derives its schema from > the defined query, columns are generated based on the query (and, similar > to a > materialized view, the underlying data for these columns is tightly coupled > to > the query definition). Therefore, we cannot simply interpret the effect of > an > single `ALTER MATERIALIZED TABLE ADD New_Column` statement. Supporting this > likely requires accompanying column default value，and raises compatibility > concerns regarding historical data, that is a complex topic we previously > discussed offline during the design process of FLIP-492. > > Also, once Ron is back in the office, he may give a more detailed comment. > > > Best, > Lincoln Lee > > > Sergey Nuyanzin <[email protected]> 于2025年10月2日周四 20:15写道： > > > Thank you Ramin > > > > In case there is no more feedback/objections > > I would start voting thread next week > > > > On Thu, Sep 25, 2025 at 10:43 AM Ramin Gharib <[email protected]> > > wrote: > > > > > > Hi Sergey, > > > Thanks for driving this! This sounds good to me! +1 > > > > > > Cheers, > > > > > > Ramin > > > > > > On Wed, Sep 24, 2025 at 2:14 PM Sergey Nuyanzin <[email protected]> > > wrote: > > > > > > > Hi everyone, > > > > I'd like to start a discussion of FLIP-550 > > > > Add similar support for CREATE/ALTER operations for MATERIALIZED > > > > TABLEs as for TABLEs [1]. > > > > > > > > This FLIP is another step towards making tables and materialized > > > > tables more consistent. There was already one improvement in that > > > > direction like FLIP-542 [2] to add DISTRIBUTION and SHOW MATERIALIZED > > > > TABLES support. However there were several more things noticed > > > > comparing behavior for CREATE and ALTER operations. For instance right > > > > now for materialized tables it is impossible to set anything but table > > > > constraint while for tables (CREATE TABLE AS) it is possible to > > > > provide schema definition since FLIP-463 [3], also ALTER operations > > > > for TABLE is a way more mature than for MATERIALIZED TABLE. This FLIP > > > > is about to decrease the difference by enabling more similar features > > > > for materialized tables. > > > > > > > > Introducing schema definition support for materialized tables will > > > > provide users with greater control and flexibility and also will unify > > > > usage of tables and materialized tables. > > > > > > > > [1] > > > > > > https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=387648095 > > > > > > > > [2] > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-542%3A+Make+materialized+table+DDL+consistent+with+regular+tables > > > > > > > > [3] > > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-463%3A+Schema+Definition+in+CREATE+TABLE+AS+Statement > > > > > > > > -- > > > > Best regards, > > > > Sergey > > > > > > > > > > > > -- > > Best regards, > > Sergey > > -- Best regards, Sergey
