Cool, thx a lot! Best, Botong
On Fri, Sep 23, 2022 at 11:46 PM Mingyu Chen <morning...@163.com> wrote: > Currently, Doris does not support multi-table materialized view. > So the mv with join is not supported yet. > > > Doris only support mv for single table, with some certain aggregation such > as sum, min, max, count, count(dinstinct) > For example, there is a base table A with column (k1, k2, v1, v2), you can > create a mv B like: > select k1, sum(v1) from A group by k1. > And now, you got a base table A and a mv B. > When data is loading into table A, it will generate a copy of data to B. > For table A, the loading data is with column (k1, k2,v1,v2), and for mv B, > the loading data will be (k1, v1). > The aggregation is done on BE side, the BE will receive data (k1, v1) and > do the aggregation (k1, sum(v1)). > > > You can see StreamLoadPlanner.java in FE for the query plan, and > DeltaWriter.h/cpp in BE for doing the aggregation. > > > > > -- > > 此致！Best Regards > 陈明雨 Mingyu Chen > > Email: > morning...@apache.org > > > > > > At 2022-09-23 23:29:44, "Botong Huang" <pku...@gmail.com> wrote: > >Thanks for the reply! > > > >I do understand from doc that the incremental update of MV is triggered > >upon base table change. > > > >But I cannot find the actual code in Doris code base that does the update, > >specifically the actual incremental plan (tree of operator generated by > the > >optimizer) to update the view result. > > > >For example, if the view is "Select * from A inner join B". Then for each > >new line in A, it needs to join all rows in B to get the correct updates > to > >the view. > > > > Or if the view is "Select avg(score) from A", then I assume the plan for > >the update should be something like "Select sum(score), count(score) from > >\delta A". > > > >Thanks, > >Botong > > > >On Fri, Sep 23, 2022 at 9:46 PM Mingyu Chen <morning...@163.com> wrote: > > > >> It controls by load process. > >> After a mv is built, all following load task will generate many copies > of > >> import data to base table and all materialized views. > >> So the incremental update happens on every load task. > >> > >> > >> > >> > >> -- > >> > >> 此致！Best Regards > >> 陈明雨 Mingyu Chen > >> > >> Email: > >> morning...@apache.org > >> > >> > >> > >> > >> > >> 在 2022-09-21 15:59:17，"Botong Huang" <pku...@gmail.com> 写道： > >> >Hi all, > >> > > >> >Does anyone know where the code is for generating the incremental plan > for > >> >updating the materialized view when the base table receives new data? > Many > >> >thanks! > >> > > >> >想知道物化视图的增量维护的plan生成的代码在哪里，谢谢！ > >> > > >> >Best, > >> >Botong > >> >
