From d468da0d65905b762dbaa647aaf8ba1ea5bca04d Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 7 Feb 2019 13:10:46 -0500 Subject: 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 --- src/backend/optimizer/util/relnode.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'src/backend/optimizer/util/relnode.c') diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index 23615f22e30..c8e94ab9fe1 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -1002,6 +1002,9 @@ get_baserel_parampathinfo(PlannerInfo *root, RelOptInfo *baserel, double rows; ListCell *lc; + /* If rel has LATERAL refs, every path for it should account for them */ + Assert(bms_is_subset(baserel->lateral_relids, required_outer)); + /* Unparameterized paths have no ParamPathInfo */ if (bms_is_empty(required_outer)) return NULL; @@ -1101,6 +1104,9 @@ get_joinrel_parampathinfo(PlannerInfo *root, RelOptInfo *joinrel, double rows; ListCell *lc; + /* If rel has LATERAL refs, every path for it should account for them */ + Assert(bms_is_subset(joinrel->lateral_relids, required_outer)); + /* Unparameterized paths have no ParamPathInfo or extra join clauses */ if (bms_is_empty(required_outer)) return NULL; @@ -1297,6 +1303,9 @@ get_appendrel_parampathinfo(RelOptInfo *appendrel, Relids required_outer) ParamPathInfo *ppi; ListCell *lc; + /* If rel has LATERAL refs, every path for it should account for them */ + Assert(bms_is_subset(appendrel->lateral_relids, required_outer)); + /* Unparameterized paths have no ParamPathInfo */ if (bms_is_empty(required_outer)) return NULL; -- cgit v1.2.3