diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out index 852b5b4707..f6d3b8ec08 100644 --- a/contrib/postgres_fdw/expected/postgres_fdw.out +++ b/contrib/postgres_fdw/expected/postgres_fdw.out @@ -2316,6 +2316,32 @@ SELECT t1."C 1" FROM "S 1"."T 1" t1, LATERAL (SELECT DISTINCT t2.c1, t3.c1 FROM 1 (10 rows) +-- join with pseudoconstant quals, not pushed down. +EXPLAIN (VERBOSE, COSTS OFF) +SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1 AND CURRENT_USER = SESSION_USER) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10; + QUERY PLAN +------------------------------------------------------------------------------- + Limit + Output: t1.c1, t2.c1, t1.c3 + -> Sort + Output: t1.c1, t2.c1, t1.c3 + Sort Key: t1.c3, t1.c1 + -> Result + Output: t1.c1, t2.c1, t1.c3 + One-Time Filter: (CURRENT_USER = SESSION_USER) + -> Hash Join + Output: t1.c1, t1.c3, t2.c1 + Hash Cond: (t2.c1 = t1.c1) + -> Foreign Scan on public.ft2 t2 + Output: t2.c1 + Remote SQL: SELECT "C 1" FROM "S 1"."T 1" + -> Hash + Output: t1.c1, t1.c3 + -> Foreign Scan on public.ft1 t1 + Output: t1.c1, t1.c3 + Remote SQL: SELECT "C 1", c3 FROM "S 1"."T 1" +(19 rows) + -- non-Var items in targetlist of the nullable rel of a join preventing -- push-down in some cases -- unable to push {ft1, ft2} diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql index 2fe8abc7af..436feee396 100644 --- a/contrib/postgres_fdw/sql/postgres_fdw.sql +++ b/contrib/postgres_fdw/sql/postgres_fdw.sql @@ -640,6 +640,9 @@ SELECT t1c1, avg(t1c1 + t2c1) FROM (SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 EXPLAIN (VERBOSE, COSTS OFF) SELECT t1."C 1" FROM "S 1"."T 1" t1, LATERAL (SELECT DISTINCT t2.c1, t3.c1 FROM ft1 t2, ft2 t3 WHERE t2.c1 = t3.c1 AND t2.c2 = t1.c2) q ORDER BY t1."C 1" OFFSET 10 LIMIT 10; SELECT t1."C 1" FROM "S 1"."T 1" t1, LATERAL (SELECT DISTINCT t2.c1, t3.c1 FROM ft1 t2, ft2 t3 WHERE t2.c1 = t3.c1 AND t2.c2 = t1.c2) q ORDER BY t1."C 1" OFFSET 10 LIMIT 10; +-- join with pseudoconstant quals, not pushed down. +EXPLAIN (VERBOSE, COSTS OFF) +SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1 AND CURRENT_USER = SESSION_USER) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10; -- non-Var items in targetlist of the nullable rel of a join preventing -- push-down in some cases diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index f047ad9ba4..4b58936fa4 100644 --- a/src/backend/optimizer/path/joinpath.c +++ b/src/backend/optimizer/path/joinpath.c @@ -24,6 +24,7 @@ #include "optimizer/pathnode.h" #include "optimizer/paths.h" #include "optimizer/planmain.h" +#include "optimizer/restrictinfo.h" #include "utils/typcache.h" /* Hook for plugins to get control in add_paths_to_joinrel() */ @@ -130,6 +131,7 @@ add_paths_to_joinrel(PlannerInfo *root, { JoinPathExtraData extra; bool mergejoin_allowed = true; + bool consider_join_pushdown = false; ListCell *lc; Relids joinrelids; @@ -321,13 +323,25 @@ add_paths_to_joinrel(PlannerInfo *root, hash_inner_and_outer(root, joinrel, outerrel, innerrel, jointype, &extra); + /* + * createplan.c does not currently support handling of pseudoconstant + * clauses assigned to joins pushed down by extensions; check if the + * restrictlist has such clauses, and if so, disallow pushing down joins. + */ + if ((joinrel->fdwroutine && + joinrel->fdwroutine->GetForeignJoinPaths) || + set_join_pathlist_hook) + consider_join_pushdown = !has_pseudoconstant_clauses(root, + restrictlist); + /* * 5. If inner and outer relations are foreign tables (or joins) belonging * to the same server and assigned to the same user to check access * permissions as, give the FDW a chance to push down joins. */ if (joinrel->fdwroutine && - joinrel->fdwroutine->GetForeignJoinPaths) + joinrel->fdwroutine->GetForeignJoinPaths && + consider_join_pushdown) joinrel->fdwroutine->GetForeignJoinPaths(root, joinrel, outerrel, innerrel, jointype, &extra); @@ -335,7 +349,8 @@ add_paths_to_joinrel(PlannerInfo *root, /* * 6. Finally, give extensions a chance to manipulate the path list. */ - if (set_join_pathlist_hook) + if (set_join_pathlist_hook && + consider_join_pushdown) set_join_pathlist_hook(root, joinrel, outerrel, innerrel, jointype, &extra); } diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c index d6d26a2b51..c1fbbb6bfe 100644 --- a/src/backend/optimizer/util/restrictinfo.c +++ b/src/backend/optimizer/util/restrictinfo.c @@ -549,6 +549,36 @@ extract_actual_join_clauses(List *restrictinfo_list, } } +/* + * has_pseudoconstant_clauses + * + * Returns true if 'restrictinfo_list' includes pseudoconstant clauses. + * + * This is used when we determine whether to allow extensions to consider + * pushing down joins in add_paths_to_joinrel(). + */ +bool +has_pseudoconstant_clauses(PlannerInfo *root, + List *restrictinfo_list) +{ + ListCell *l; + + /* No need to look if we know there are no pseudoconstants */ + if (!root->hasPseudoConstantQuals) + return false; + + /* See if there are pseudoconstants in the RestrictInfo list */ + foreach(l, restrictinfo_list) + { + RestrictInfo *rinfo = lfirst_node(RestrictInfo, l); + + if (rinfo->pseudoconstant && + !rinfo_is_constant_true(rinfo)) + return true; + } + return false; +} + /* * join_clause_is_movable_to * Test whether a join clause is a safe candidate for parameterization diff --git a/src/include/optimizer/restrictinfo.h b/src/include/optimizer/restrictinfo.h index e140e619ac..14cdce750c 100644 --- a/src/include/optimizer/restrictinfo.h +++ b/src/include/optimizer/restrictinfo.h @@ -43,6 +43,8 @@ extern void extract_actual_join_clauses(List *restrictinfo_list, Relids joinrelids, List **joinquals, List **otherquals); +extern bool has_pseudoconstant_clauses(PlannerInfo *root, + List *restrictinfo_list); extern bool join_clause_is_movable_to(RestrictInfo *rinfo, RelOptInfo *baserel); extern bool join_clause_is_movable_into(RestrictInfo *rinfo, Relids currentrelids,