On Tue, Sep 20, 2022 at 4:53 PM David Rowley <dgrowle...@gmail.com> wrote: > Thank you for having a look at the patch. > > On Tue, 20 Sept 2022 at 18:41, Amit Langote <amitlangot...@gmail.com> wrote: > > Agreed, though the patch's changes to tests does not seem to have to > > do with join removal? I don't really understand what the test changes > > are all about. I wonder why the patch doesn't instead add the test > > case that Arne showed in the file he attached with [1]. > > [1] > > https://www.postgresql.org/message-id/2641568c18de40e8b1528fc9d4d80127%40index.de > > I adjusted a test in partition_join.sql to add an additional column to > the fract_t table. Before the change that table only had a single > column and due to the query's join condition being USING(id), none of > the columns from the left joined table were being used. That resulted > in the updated code performing a left join removal as it was passing > the checks for no columns being used in the left joined table in > analyzejoins.c. The test in partition_join.sql claims to be testing > "partitionwise join with fractional paths", so I thought we'd better > not have a query that the planner removes the join when we're meant to > be testing joins.
Ah, got it, thanks for the explanation. > It probably wouldn't hurt to have a new test to ensure left join > removals work with a partitioned table. That should go in join.sql > along with the other join removal tests. Makes sense. > I didn't study Arne's patch > to see what test he added. I was only interested in writing enough > code so I could check there was no good reason not to add the > partitioned index into RelOptInfo.indexlist. Arne sent me an off-list > message to say he's planning on working on the patch that uses the > existing field instead of the new one he originally added. Let's hold > off for that patch. Ok, sure. -- Thanks, Amit Langote EDB: http://www.enterprisedb.com
