Hi, On 2025-05-20 16:18:57 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > >> I'm tempted to back-patch this: the plan tree damage seems harmless at > >> present, but maybe it'd become less harmless with future fixes. > > > There are *some* cases where this changes the explain output, but but the > > new > > output is more correct, I think: > > ... > > I suspect this is an argument for backpatching, not against - seems that > > deparsing could end up creating bogus output in cases where it could matter? > > Not sure if such cases are reachable via views (and thus pg_dump) or > > postgres_fdw, but it seems possible. > > I don't believe that we guarantee EXPLAIN output to be 100% valid SQL, > so I doubt there's a correctness argument here; certainly it'd not > affect pg_dump.
I wasn't thinking of EXPLAIN itself, but was wondering whether it's possible to create a view, rule or such that is affected by the output change. Would be a weird case, if it existed. > I'm curious though: what was the test case you were looking at? It's a modified query from our regression tests, I had added some debugging to find cases where the targetlists differed. I attached the extracted, somewhat modified, sql script. Greetings, Andres Freund
repro-dml-returning.sql
Description: application/sql
