The logical plan should show you where the cross join is needed. Here is where it is logged: https://github.com/apache/beam/blob/master/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/planner/BeamQueryPlanner.java#L150
(It should probably be put to DEBUG level) If I look at the original template, like https://github.com/gregrahn/tpcds-kit/blob/master/query_templates/query9.tpl I see conditions "[RC.1]". Are those templates expected to be filled with references to the `reason` table, perhaps? How does that change things? I still think it would be good to support CROSS JOIN if we can - the problem of course is huge data size, but when one side is small it would be good for it to work simply. Kenn On Tue, May 15, 2018 at 7:41 AM Kai Jiang <[email protected]> wrote: > Hi everyone, > > To prove the idea of GSoC project, I was working on some simple TPC-DS > queries running with given generated data on direct runner. query example > <https://gist.github.com/vectorijk/7c54f90aeebfd6fd9e9d2ee224bfed50> > > The example is executed with TPC-DS query 9 > <https://gist.github.com/vectorijk/7c54f90aeebfd6fd9e9d2ee224bfed50#file-tpcdssql-java-L176-L222>. > Briefly, Query 9 uses case when clauses to select 5 counting numbers from > store_sales > (table 1). In order to show those result numbers, case when clause inside > one select clause. In short, it looks like: > SELECT > > CASE WHEN ( SELECT count(*) FROM table 1 WHERE..... ) > THEN condition 1 > ELSE condition 2, > ..... > CASE WHEN ..... > > FROM table 2 > > IIUC, this query doesn't need join operation on table 1 and table 2 since > outside select clause doesn't need to interfere with table 1. > But, the program shows it does and throws errors message said > "java.lang.UnsupportedOperationException: CROSS JOIN is not supported". (error > message detail > <https://gist.github.com/vectorijk/5619a20485edc01113a56e348f87b0c3>) > > To make the query work, I am wondering where I can start with: > 1. see logic plan? > Will logic plan explain why the query need CROSS JOIN? > > 2. cross join support? > I checked all queries in TPC-DS benchmark. Almost every query uses cross > join. It is an important feature needs to implement. Unlike other join, it > consumes a lot of computing resource. But, I think we need cross join in > the future. and support both in join-library? I noticed James has open > BEAM-2194 <https://issues.apache.org/jira/browse/BEAM-2194> for > supporting cross join. > > Looking forward to comments! > > Best, > Kai > > ᐧ >
