Ensure that foreign scans with lateral refs are planned correctly.
As reported in bug #15613 from Srinivasan S A, file_fdw and postgres_fdw
neglected to mark plain baserel foreign paths as parameterized when the
relation has lateral_relids. Other FDWs have surely copied this mistake,
so rather than just patching those two modules, install a band-aid fix
in create_foreignscan_path to rectify the mistake centrally.
Although the band-aid is enough to fix the visible symptom, correct
the calls in file_fdw and postgres_fdw anyway, so that they are valid
examples for external FDWs.
Also, since the band-aid isn't enough to make this work for parameterized
foreign joins, throw an elog(ERROR) if such a case is passed to
create_foreignscan_path. This shouldn't pose much of a problem for
existing external FDWs, since it's likely they aren't trying to make such
paths anyway (though some of them may need a defense against joins with
lateral_relids, similar to the one this patch installs into postgres_fdw).
Add some assertions in relnode.c to catch future occurrences of the same
error --- in particular, as backstop against core-code mistakes like the
one fixed by commit bdd9a99aa.
Discussion: https://postgr.es/m/15613-092be1be9576c728@postgresql.org
Branch
------
REL9_6_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/d468da0d65905b762dbaa647aaf8ba1ea5bca04d
Modified Files
--------------
contrib/file_fdw/file_fdw.c | 6 ++-
contrib/postgres_fdw/expected/postgres_fdw.out | 56 ++++++++++++++++++++++++++
contrib/postgres_fdw/postgres_fdw.c | 16 ++++++--
contrib/postgres_fdw/sql/postgres_fdw.sql | 26 ++++++++++++
src/backend/optimizer/util/pathnode.c | 23 +++++++++++
src/backend/optimizer/util/relnode.c | 9 +++++
6 files changed, 132 insertions(+), 4 deletions(-)
