is-pushed-down-followup.patch

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 30e5726..a46160d 100644
*** a/contrib/postgres_fdw/postgres_fdw.c
--- b/contrib/postgres_fdw/postgres_fdw.c
*************** foreign_join_ok(PlannerInfo *root, RelOp
*** 4705,4711 ****
  		bool		is_remote_clause = is_foreign_expr(root, joinrel,
  													   rinfo->clause);
  
! 		if (IS_OUTER_JOIN(jointype) && !rinfo->is_pushed_down)
  		{
  			if (!is_remote_clause)
  				return false;
--- 4705,4712 ----
  		bool		is_remote_clause = is_foreign_expr(root, joinrel,
  													   rinfo->clause);
  
! 		if (IS_OUTER_JOIN(jointype) &&
! 			!RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
  		{
  			if (!is_remote_clause)
  				return false;
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 47729de..10d4114 100644
*** a/src/backend/optimizer/path/costsize.c
--- b/src/backend/optimizer/path/costsize.c
*************** static bool has_indexed_join_quals(NestP
*** 159,164 ****
--- 159,165 ----
  static double approx_tuple_count(PlannerInfo *root, JoinPath *path,
  				   List *quals);
  static double calc_joinrel_size_estimate(PlannerInfo *root,
+ 						   RelOptInfo *joinrel,
  						   RelOptInfo *outer_rel,
  						   RelOptInfo *inner_rel,
  						   double outer_rows,
*************** compute_semi_anti_join_factors(PlannerIn
*** 4055,4066 ****
  	 */
  	if (IS_OUTER_JOIN(jointype))
  	{
  		joinquals = NIL;
  		foreach(l, restrictlist)
  		{
  			RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
  
! 			if (!rinfo->is_pushed_down)
  				joinquals = lappend(joinquals, rinfo);
  		}
  	}
--- 4056,4069 ----
  	 */
  	if (IS_OUTER_JOIN(jointype))
  	{
+ 		Relids		joinrelids = bms_union(outerrel->relids, innerrel->relids);
+ 
  		joinquals = NIL;
  		foreach(l, restrictlist)
  		{
  			RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
  
! 			if (!RINFO_IS_PUSHED_DOWN(rinfo, joinrelids))
  				joinquals = lappend(joinquals, rinfo);
  		}
  	}
*************** set_joinrel_size_estimates(PlannerInfo *
*** 4375,4380 ****
--- 4378,4384 ----
  						   List *restrictlist)
  {
  	rel->rows = calc_joinrel_size_estimate(root,
+ 										   rel,
  										   outer_rel,
  										   inner_rel,
  										   outer_rel->rows,
*************** get_parameterized_joinrel_size(PlannerIn
*** 4417,4422 ****
--- 4421,4427 ----
  	 * estimate for any pair with the same parameterization.
  	 */
  	nrows = calc_joinrel_size_estimate(root,
+ 									   rel,
  									   outer_path->parent,
  									   inner_path->parent,
  									   outer_path->rows,
*************** get_parameterized_joinrel_size(PlannerIn
*** 4440,4445 ****
--- 4445,4451 ----
   */
  static double
  calc_joinrel_size_estimate(PlannerInfo *root,
+ 						   RelOptInfo *joinrel,
  						   RelOptInfo *outer_rel,
  						   RelOptInfo *inner_rel,
  						   double outer_rows,
*************** calc_joinrel_size_estimate(PlannerInfo *
*** 4492,4498 ****
  		{
  			RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
  
! 			if (rinfo->is_pushed_down)
  				pushedquals = lappend(pushedquals, rinfo);
  			else
  				joinquals = lappend(joinquals, rinfo);
--- 4498,4504 ----
  		{
  			RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
  
! 			if (RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
  				pushedquals = lappend(pushedquals, rinfo);
  			else
  				joinquals = lappend(joinquals, rinfo);
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
index 3fd3cc7..f47dd81 100644
*** a/src/backend/optimizer/path/joinpath.c
--- b/src/backend/optimizer/path/joinpath.c
*************** hash_inner_and_outer(PlannerInfo *root,
*** 1700,1706 ****
  		 * If processing an outer join, only use its own join clauses for
  		 * hashing.  For inner joins we need not be so picky.
  		 */
! 		if (isouterjoin && restrictinfo->is_pushed_down)
  			continue;
  
  		if (!restrictinfo->can_join ||
--- 1700,1706 ----
  		 * If processing an outer join, only use its own join clauses for
  		 * hashing.  For inner joins we need not be so picky.
  		 */
! 		if (isouterjoin && RINFO_IS_PUSHED_DOWN(restrictinfo, joinrel->relids))
  			continue;
  
  		if (!restrictinfo->can_join ||
*************** select_mergejoin_clauses(PlannerInfo *ro
*** 1947,1953 ****
  		 * we don't set have_nonmergeable_joinclause here because pushed-down
  		 * clauses will become otherquals not joinquals.)
  		 */
! 		if (isouterjoin && restrictinfo->is_pushed_down)
  			continue;
  
  		/* Check that clause is a mergeable operator clause */
--- 1947,1953 ----
  		 * we don't set have_nonmergeable_joinclause here because pushed-down
  		 * clauses will become otherquals not joinquals.)
  		 */
! 		if (isouterjoin && RINFO_IS_PUSHED_DOWN(restrictinfo, joinrel->relids))
  			continue;
  
  		/* Check that clause is a mergeable operator clause */
diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c
index 5d66cfb..6d41d30 100644
*** a/src/backend/optimizer/path/joinrels.c
--- b/src/backend/optimizer/path/joinrels.c
*************** static bool has_join_restriction(Planner
*** 35,40 ****
--- 35,41 ----
  static bool has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel);
  static bool is_dummy_rel(RelOptInfo *rel);
  static bool restriction_is_constant_false(List *restrictlist,
+ 							  RelOptInfo *joinrel,
  							  bool only_pushed_down);
  static void populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
  							RelOptInfo *rel2, RelOptInfo *joinrel,
*************** populate_joinrel_with_paths(PlannerInfo 
*** 780,786 ****
  	{
  		case JOIN_INNER:
  			if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
! 				restriction_is_constant_false(restrictlist, false))
  			{
  				mark_dummy_rel(joinrel);
  				break;
--- 781,787 ----
  	{
  		case JOIN_INNER:
  			if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
! 				restriction_is_constant_false(restrictlist, joinrel, false))
  			{
  				mark_dummy_rel(joinrel);
  				break;
*************** populate_joinrel_with_paths(PlannerInfo 
*** 794,805 ****
  			break;
  		case JOIN_LEFT:
  			if (is_dummy_rel(rel1) ||
! 				restriction_is_constant_false(restrictlist, true))
  			{
  				mark_dummy_rel(joinrel);
  				break;
  			}
! 			if (restriction_is_constant_false(restrictlist, false) &&
  				bms_is_subset(rel2->relids, sjinfo->syn_righthand))
  				mark_dummy_rel(rel2);
  			add_paths_to_joinrel(root, joinrel, rel1, rel2,
--- 795,806 ----
  			break;
  		case JOIN_LEFT:
  			if (is_dummy_rel(rel1) ||
! 				restriction_is_constant_false(restrictlist, joinrel, true))
  			{
  				mark_dummy_rel(joinrel);
  				break;
  			}
! 			if (restriction_is_constant_false(restrictlist, joinrel, false) &&
  				bms_is_subset(rel2->relids, sjinfo->syn_righthand))
  				mark_dummy_rel(rel2);
  			add_paths_to_joinrel(root, joinrel, rel1, rel2,
*************** populate_joinrel_with_paths(PlannerInfo 
*** 811,817 ****
  			break;
  		case JOIN_FULL:
  			if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) ||
! 				restriction_is_constant_false(restrictlist, true))
  			{
  				mark_dummy_rel(joinrel);
  				break;
--- 812,818 ----
  			break;
  		case JOIN_FULL:
  			if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) ||
! 				restriction_is_constant_false(restrictlist, joinrel, true))
  			{
  				mark_dummy_rel(joinrel);
  				break;
*************** populate_joinrel_with_paths(PlannerInfo 
*** 847,853 ****
  				bms_is_subset(sjinfo->min_righthand, rel2->relids))
  			{
  				if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
! 					restriction_is_constant_false(restrictlist, false))
  				{
  					mark_dummy_rel(joinrel);
  					break;
--- 848,854 ----
  				bms_is_subset(sjinfo->min_righthand, rel2->relids))
  			{
  				if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
! 					restriction_is_constant_false(restrictlist, joinrel, false))
  				{
  					mark_dummy_rel(joinrel);
  					break;
*************** populate_joinrel_with_paths(PlannerInfo 
*** 870,876 ****
  								   sjinfo) != NULL)
  			{
  				if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
! 					restriction_is_constant_false(restrictlist, false))
  				{
  					mark_dummy_rel(joinrel);
  					break;
--- 871,877 ----
  								   sjinfo) != NULL)
  			{
  				if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
! 					restriction_is_constant_false(restrictlist, joinrel, false))
  				{
  					mark_dummy_rel(joinrel);
  					break;
*************** populate_joinrel_with_paths(PlannerInfo 
*** 885,896 ****
  			break;
  		case JOIN_ANTI:
  			if (is_dummy_rel(rel1) ||
! 				restriction_is_constant_false(restrictlist, true))
  			{
  				mark_dummy_rel(joinrel);
  				break;
  			}
! 			if (restriction_is_constant_false(restrictlist, false) &&
  				bms_is_subset(rel2->relids, sjinfo->syn_righthand))
  				mark_dummy_rel(rel2);
  			add_paths_to_joinrel(root, joinrel, rel1, rel2,
--- 886,897 ----
  			break;
  		case JOIN_ANTI:
  			if (is_dummy_rel(rel1) ||
! 				restriction_is_constant_false(restrictlist, joinrel, true))
  			{
  				mark_dummy_rel(joinrel);
  				break;
  			}
! 			if (restriction_is_constant_false(restrictlist, joinrel, false) &&
  				bms_is_subset(rel2->relids, sjinfo->syn_righthand))
  				mark_dummy_rel(rel2);
  			add_paths_to_joinrel(root, joinrel, rel1, rel2,
*************** mark_dummy_rel(RelOptInfo *rel)
*** 1249,1258 ****
   * decide there's no match for an outer row, which is pretty stupid.  So,
   * we need to detect the case.
   *
!  * If only_pushed_down is true, then consider only pushed-down quals.
   */
  static bool
! restriction_is_constant_false(List *restrictlist, bool only_pushed_down)
  {
  	ListCell   *lc;
  
--- 1250,1262 ----
   * decide there's no match for an outer row, which is pretty stupid.  So,
   * we need to detect the case.
   *
!  * If only_pushed_down is true, then consider only quals that are pushed-down
!  * from the point of view of the joinrel.
   */
  static bool
! restriction_is_constant_false(List *restrictlist,
! 							  RelOptInfo *joinrel,
! 							  bool only_pushed_down)
  {
  	ListCell   *lc;
  
*************** restriction_is_constant_false(List *rest
*** 1266,1272 ****
  	{
  		RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
  
! 		if (only_pushed_down && !rinfo->is_pushed_down)
  			continue;
  
  		if (rinfo->clause && IsA(rinfo->clause, Const))
--- 1270,1276 ----
  	{
  		RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
  
! 		if (only_pushed_down && !RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
  			continue;
  
  		if (rinfo->clause && IsA(rinfo->clause, Const))
*************** try_partitionwise_join(PlannerInfo *root
*** 1411,1418 ****
   * partition keys from given relations being joined.
   */
  bool
! have_partkey_equi_join(RelOptInfo *rel1, RelOptInfo *rel2, JoinType jointype,
! 					   List *restrictlist)
  {
  	PartitionScheme part_scheme = rel1->part_scheme;
  	ListCell   *lc;
--- 1415,1423 ----
   * partition keys from given relations being joined.
   */
  bool
! have_partkey_equi_join(RelOptInfo *joinrel,
! 					   RelOptInfo *rel1, RelOptInfo *rel2,
! 					   JoinType jointype, List *restrictlist)
  {
  	PartitionScheme part_scheme = rel1->part_scheme;
  	ListCell   *lc;
*************** have_partkey_equi_join(RelOptInfo *rel1,
*** 1438,1444 ****
  		int			ipk2;
  
  		/* If processing an outer join, only use its own join clauses. */
! 		if (IS_OUTER_JOIN(jointype) && rinfo->is_pushed_down)
  			continue;
  
  		/* Skip clauses which can not be used for a join. */
--- 1443,1450 ----
  		int			ipk2;
  
  		/* If processing an outer join, only use its own join clauses. */
! 		if (IS_OUTER_JOIN(jointype) &&
! 			RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
  			continue;
  
  		/* Skip clauses which can not be used for a join. */
diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c
index ef25fef..c5c4362 100644
*** a/src/backend/optimizer/plan/analyzejoins.c
--- b/src/backend/optimizer/plan/analyzejoins.c
*************** join_is_removable(PlannerInfo *root, Spe
*** 253,260 ****
  		 * above the outer join, even if it references no other rels (it might
  		 * be from WHERE, for example).
  		 */
! 		if (restrictinfo->is_pushed_down ||
! 			!bms_equal(restrictinfo->required_relids, joinrelids))
  		{
  			/*
  			 * If such a clause actually references the inner rel then join
--- 253,259 ----
  		 * above the outer join, even if it references no other rels (it might
  		 * be from WHERE, for example).
  		 */
! 		if (RINFO_IS_PUSHED_DOWN(restrictinfo, joinrelids))
  		{
  			/*
  			 * If such a clause actually references the inner rel then join
*************** remove_rel_from_query(PlannerInfo *root,
*** 422,429 ****
  
  		remove_join_clause_from_rels(root, rinfo, rinfo->required_relids);
  
! 		if (rinfo->is_pushed_down ||
! 			!bms_equal(rinfo->required_relids, joinrelids))
  		{
  			/* Recheck that qual doesn't actually reference the target rel */
  			Assert(!bms_is_member(relid, rinfo->clause_relids));
--- 421,427 ----
  
  		remove_join_clause_from_rels(root, rinfo, rinfo->required_relids);
  
! 		if (RINFO_IS_PUSHED_DOWN(rinfo, joinrelids))
  		{
  			/* Recheck that qual doesn't actually reference the target rel */
  			Assert(!bms_is_member(relid, rinfo->clause_relids));
*************** is_innerrel_unique_for(PlannerInfo *root
*** 1080,1085 ****
--- 1078,1084 ----
  					   JoinType jointype,
  					   List *restrictlist)
  {
+ 	Relids		joinrelids = bms_union(outerrelids, innerrel->relids);
  	List	   *clause_list = NIL;
  	ListCell   *lc;
  
*************** is_innerrel_unique_for(PlannerInfo *root
*** 1098,1104 ****
  		 * As noted above, if it's a pushed-down clause and we're at an outer
  		 * join, we can't use it.
  		 */
! 		if (restrictinfo->is_pushed_down && IS_OUTER_JOIN(jointype))
  			continue;
  
  		/* Ignore if it's not a mergejoinable clause */
--- 1097,1104 ----
  		 * As noted above, if it's a pushed-down clause and we're at an outer
  		 * join, we can't use it.
  		 */
! 		if (IS_OUTER_JOIN(jointype) &&
! 			RINFO_IS_PUSHED_DOWN(restrictinfo, joinrelids))
  			continue;
  
  		/* Ignore if it's not a mergejoinable clause */
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index a436b53..01335db 100644
*** a/src/backend/optimizer/plan/initsplan.c
--- b/src/backend/optimizer/plan/initsplan.c
*************** distribute_qual_to_rels(PlannerInfo *roo
*** 1775,1780 ****
--- 1775,1785 ----
  	 * attach quals to the lowest level where they can be evaluated.  But
  	 * if we were ever to re-introduce a mechanism for delaying evaluation
  	 * of "expensive" quals, this area would need work.
+ 	 *
+ 	 * Note: generally, use of is_pushed_down has to go through the macro
+ 	 * RINFO_IS_PUSHED_DOWN, because that flag alone is not always sufficient
+ 	 * to tell whether a clause must be treated as pushed-down in context.
+ 	 * This seems like another reason why it should perhaps be rethought.
  	 *----------
  	 */
  	if (is_deduced)
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index fc19f89..82b7842 100644
*** a/src/backend/optimizer/util/relnode.c
--- b/src/backend/optimizer/util/relnode.c
*************** build_joinrel_partition_info(RelOptInfo 
*** 1629,1635 ****
  	 */
  	if (!IS_PARTITIONED_REL(outer_rel) || !IS_PARTITIONED_REL(inner_rel) ||
  		outer_rel->part_scheme != inner_rel->part_scheme ||
! 		!have_partkey_equi_join(outer_rel, inner_rel, jointype, restrictlist))
  	{
  		Assert(!IS_PARTITIONED_REL(joinrel));
  		return;
--- 1629,1636 ----
  	 */
  	if (!IS_PARTITIONED_REL(outer_rel) || !IS_PARTITIONED_REL(inner_rel) ||
  		outer_rel->part_scheme != inner_rel->part_scheme ||
! 		!have_partkey_equi_join(joinrel, outer_rel, inner_rel,
! 								jointype, restrictlist))
  	{
  		Assert(!IS_PARTITIONED_REL(joinrel));
  		return;
diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c
index 65c1abc..edf5a48 100644
*** a/src/backend/optimizer/util/restrictinfo.c
--- b/src/backend/optimizer/util/restrictinfo.c
*************** extract_actual_clauses(List *restrictinf
*** 373,379 ****
   * extract_actual_join_clauses
   *
   * Extract bare clauses from 'restrictinfo_list', separating those that
!  * syntactically match the join level from those that were pushed down.
   * Pseudoconstant clauses are excluded from the results.
   *
   * This is only used at outer joins, since for plain joins we don't care
--- 373,379 ----
   * extract_actual_join_clauses
   *
   * Extract bare clauses from 'restrictinfo_list', separating those that
!  * semantically match the join level from those that were pushed down.
   * Pseudoconstant clauses are excluded from the results.
   *
   * This is only used at outer joins, since for plain joins we don't care
*************** extract_actual_join_clauses(List *restri
*** 394,408 ****
  	{
  		RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
  
! 		/*
! 		 * We must check both is_pushed_down and required_relids, since an
! 		 * outer-join clause that's been pushed down to some lower join level
! 		 * via path parameterization will not be marked is_pushed_down;
! 		 * nonetheless, it must be treated as a filter clause not a join
! 		 * clause so far as the lower join level is concerned.
! 		 */
! 		if (rinfo->is_pushed_down ||
! 			!bms_is_subset(rinfo->required_relids, joinrelids))
  		{
  			if (!rinfo->pseudoconstant)
  				*otherquals = lappend(*otherquals, rinfo->clause);
--- 394,400 ----
  	{
  		RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
  
! 		if (RINFO_IS_PUSHED_DOWN(rinfo, joinrelids))
  		{
  			if (!rinfo->pseudoconstant)
  				*otherquals = lappend(*otherquals, rinfo->clause);
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index d6dbf15..2108b6a 100644
*** a/src/include/nodes/relation.h
--- b/src/include/nodes/relation.h
*************** typedef struct LimitPath
*** 1789,1795 ****
   * if we decide that it can be pushed down into the nullable side of the join.
   * In that case it acts as a plain filter qual for wherever it gets evaluated.
   * (In short, is_pushed_down is only false for non-degenerate outer join
!  * conditions.  Possibly we should rename it to reflect that meaning?)
   *
   * RestrictInfo nodes also contain an outerjoin_delayed flag, which is true
   * if the clause's applicability must be delayed due to any outer joins
--- 1789,1796 ----
   * if we decide that it can be pushed down into the nullable side of the join.
   * In that case it acts as a plain filter qual for wherever it gets evaluated.
   * (In short, is_pushed_down is only false for non-degenerate outer join
!  * conditions.  Possibly we should rename it to reflect that meaning?  But
!  * see also the comments for RINFO_IS_PUSHED_DOWN, below.)
   *
   * RestrictInfo nodes also contain an outerjoin_delayed flag, which is true
   * if the clause's applicability must be delayed due to any outer joins
*************** typedef struct RestrictInfo
*** 1932,1937 ****
--- 1933,1952 ----
  } RestrictInfo;
  
  /*
+  * This macro embodies the correct way to test whether a RestrictInfo is
+  * "pushed down" to a given outer join, that is, should be treated as a filter
+  * clause rather than a join clause at that outer join.  This is certainly so
+  * if is_pushed_down is true; but examining that is not sufficient anymore,
+  * because outer-join clauses will get pushed down to lower outer joins when
+  * we generate a path for the lower outer join that is parameterized by the
+  * LHS of the upper one.  We can detect such a clause by noting that its
+  * required_relids exceed the scope of the join.
+  */
+ #define RINFO_IS_PUSHED_DOWN(rinfo, joinrelids) \
+ 	((rinfo)->is_pushed_down || \
+ 	 !bms_is_subset((rinfo)->required_relids, joinrelids))
+ 
+ /*
   * Since mergejoinscansel() is a relatively expensive function, and would
   * otherwise be invoked many times while planning a large join tree,
   * we go out of our way to cache its results.  Each mergejoinable
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 50e180c..f181586 100644
*** a/src/include/optimizer/paths.h
--- b/src/include/optimizer/paths.h
*************** extern bool have_join_order_restriction(
*** 115,121 ****
  extern bool have_dangerous_phv(PlannerInfo *root,
  				   Relids outer_relids, Relids inner_params);
  extern void mark_dummy_rel(RelOptInfo *rel);
! extern bool have_partkey_equi_join(RelOptInfo *rel1, RelOptInfo *rel2,
  					   JoinType jointype, List *restrictlist);
  
  /*
--- 115,122 ----
  extern bool have_dangerous_phv(PlannerInfo *root,
  				   Relids outer_relids, Relids inner_params);
  extern void mark_dummy_rel(RelOptInfo *rel);
! extern bool have_partkey_equi_join(RelOptInfo *joinrel,
! 					   RelOptInfo *rel1, RelOptInfo *rel2,
  					   JoinType jointype, List *restrictlist);
  
  /*