**Problem**: Currently, we error out if we detect recurring tuples in
one side without checking the other side of the join.
**Solution**: When one side of the full join consists recurring tuples
and the other side consists nonrecurring tuples, we should not pushdown
to prevent duplicate results. Otherwise, safe to pushdown.
This commit is inspired by a commit
dc9c3b0ff21465fa89d71eecf5e6cc956d647eca from PostgreSQL 15 that shares
the same header.
I also removed some gitignore rules so that I can add some files to git
worktree. We used to ignore the generated files, that are no longer
generated after this commit.
--------------------
Below is the commit message from PostgreSQL 15 commit
dc9c3b0ff21465fa89d71eecf5e6cc956d647eca :
"git mv" all the input/*.source and output/*.source files into
the corresponding sql/ and expected/ directories. Then remove
the pg_regress and Makefile infrastructure associated with
dynamic translation.
Discussion: https://postgr.es/m/1655733.1639871614@sss.pgh.pa.us
Onur Tirtir
aykut-bozkurt
Hanefi Onaldi