diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2019-02-07 13:10:46 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2019-02-07 13:10:46 -0500 |
| commit | 876fd37fc8126c4725c2aca709a6be34c2001258 (patch) | |
| tree | 629c99425ea34cce59dec4b8c5d6a318af64d71e /contrib/postgres_fdw/postgres_fdw.c | |
| parent | b33d5e076eecb5664dc9aaf9dd7e1d792a7cc774 (diff) | |
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
Diffstat (limited to 'contrib/postgres_fdw/postgres_fdw.c')
| -rw-r--r-- | contrib/postgres_fdw/postgres_fdw.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index 5a4a47dbd2b..c5d9ee43dd9 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -547,13 +547,16 @@ postgresGetForeignPaths(PlannerInfo *root, * baserestrict conditions we were able to send to remote, there might * actually be an indexscan happening there). We already did all the work * to estimate cost and size of this path. + * + * Although this path uses no join clauses, it could still have required + * parameterization due to LATERAL refs in its tlist. */ path = create_foreignscan_path(root, baserel, fpinfo->rows, fpinfo->startup_cost, fpinfo->total_cost, NIL, /* no pathkeys */ - NULL, /* no outer rel either */ + baserel->lateral_relids, NIL); /* no fdw_private list */ add_path(baserel, (Path *) path); |