diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
index 0f04033166588adc157d18f5d50ce1c1f07ddb30..53d8fdd6e5bb28c34b3867580c6f037b818c548c 100644
--- a/src/backend/optimizer/path/joinpath.c
+++ b/src/backend/optimizer/path/joinpath.c
@@ -254,54 +254,6 @@ allow_star_schema_join(PlannerInfo *root,
bms_nonempty_difference(innerparams, outerrelids));
}
-/*
- * There's a pitfall for creating parameterized nestloops: suppose the inner
- * rel (call it A) has a parameter that is a PlaceHolderVar, and that PHV's
- * minimum eval_at set includes the outer rel (B) and some third rel (C).
- * We might think we could create a B/A nestloop join that's parameterized by
- * C. But we would end up with a plan in which the PHV's expression has to be
- * evaluated as a nestloop parameter at the B/A join; and the executor is only
- * set up to handle simple Vars as NestLoopParams. Rather than add complexity
- * and overhead to the executor for such corner cases, it seems better to
- * forbid the join. (Note that existence of such a PHV probably means there
- * is a join order constraint that will cause us to consider joining B and C
- * directly; so we can still make use of A's parameterized path with B+C.)
- * So we check whether any PHVs used in the query could pose such a hazard.
- * We don't have any simple way of checking whether a risky PHV would actually
- * be used in the inner plan, and the case is so unusual that it doesn't seem
- * worth working very hard on it.
- *
- * This case can occur whether or not the join's remaining parameterization
- * overlaps param_source_rels, so we have to check for it separately from
- * allow_star_schema_join, even though it looks much like a star-schema case.
- */
-static inline bool
-check_hazardous_phv(PlannerInfo *root,
- Path *outer_path,
- Path *inner_path)
-{
- Relids innerparams = PATH_REQ_OUTER(inner_path);
- Relids outerrelids = outer_path->parent->relids;
- ListCell *lc;
-
- foreach(lc, root->placeholder_list)
- {
- PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
-
- if (!bms_is_subset(phinfo->ph_eval_at, innerparams))
- continue; /* ignore, could not be a nestloop param */
- if (!bms_overlap(phinfo->ph_eval_at, outerrelids))
- continue; /* ignore, not relevant to this join */
- if (bms_is_subset(phinfo->ph_eval_at, outerrelids))
- continue; /* safe, it can be eval'd within outerrel */
- /* Otherwise, it's potentially unsafe, so reject the join */
- return false;
- }
-
- /* OK to perform the join */
- return true;
-}
-
/*
* try_nestloop_path
* Consider a nestloop join path; if it appears useful, push it into
@@ -322,31 +274,24 @@ try_nestloop_path(PlannerInfo *root,
/*
* Check to see if proposed path is still parameterized, and reject if the
* parameterization wouldn't be sensible --- unless allow_star_schema_join
- * says to allow it anyway. Also, we must reject if check_hazardous_phv
- * doesn't like the look of it.
+ * says to allow it anyway. Also, we must reject if have_dangerous_phv
+ * doesn't like the look of it, which could only happen if the nestloop is
+ * still parameterized.
*/
required_outer = calc_nestloop_required_outer(outer_path,
inner_path);
if (required_outer &&
((!bms_overlap(required_outer, extra->param_source_rels) &&
!allow_star_schema_join(root, outer_path, inner_path)) ||
- !check_hazardous_phv(root, outer_path, inner_path)))
+ have_dangerous_phv(root,
+ outer_path->parent->relids,
+ PATH_REQ_OUTER(inner_path))))
{
/* Waste no memory when we reject a path here */
bms_free(required_outer);
return;
}
- /*
- * Independently of that, add parameterization needed for any
- * PlaceHolderVars that need to be computed at the join. We can handle
- * that just by adding joinrel->lateral_relids; that might include some
- * rels that are already in required_outer, but no harm done. (Note that
- * lateral_relids is exactly NULL if empty, so this will not break the
- * property that required_outer is too.)
- */
- required_outer = bms_add_members(required_outer, joinrel->lateral_relids);
-
/*
* Do a precheck to quickly eliminate obviously-inferior paths. We
* calculate a cheap lower bound on the path's cost and then use
@@ -418,12 +363,6 @@ try_mergejoin_path(PlannerInfo *root,
return;
}
- /*
- * Independently of that, add parameterization needed for any
- * PlaceHolderVars that need to be computed at the join.
- */
- required_outer = bms_add_members(required_outer, joinrel->lateral_relids);
-
/*
* If the given paths are already well enough ordered, we can skip doing
* an explicit sort.
@@ -500,12 +439,6 @@ try_hashjoin_path(PlannerInfo *root,
return;
}
- /*
- * Independently of that, add parameterization needed for any
- * PlaceHolderVars that need to be computed at the join.
- */
- required_outer = bms_add_members(required_outer, joinrel->lateral_relids);
-
/*
* See comments in try_nestloop_path(). Also note that hashjoin paths
* never have any output pathkeys, per comments in create_hashjoin_path.
diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c
index 9f0212fad23b0cefc05ee7a8c8d5a038206defe4..47837e1eda8762635166a290aa38b975af6920f0 100644
--- a/src/backend/optimizer/path/joinrels.c
+++ b/src/backend/optimizer/path/joinrels.c
@@ -332,9 +332,6 @@ join_is_legal(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
bool reversed;
bool unique_ified;
bool must_be_leftjoin;
- bool lateral_fwd;
- bool lateral_rev;
- Relids join_lateral_rels;
ListCell *l;
/*
@@ -527,75 +524,126 @@ join_is_legal(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
/*
* We also have to check for constraints imposed by LATERAL references.
- * The proposed rels could each contain lateral references to the other,
- * in which case the join is impossible. If there are lateral references
- * in just one direction, then the join has to be done with a nestloop
- * with the lateral referencer on the inside. If the join matches an SJ
- * that cannot be implemented by such a nestloop, the join is impossible.
*/
- lateral_fwd = lateral_rev = false;
- foreach(l, root->lateral_info_list)
+ if (root->hasLateralRTEs)
{
- LateralJoinInfo *ljinfo = (LateralJoinInfo *) lfirst(l);
+ bool lateral_fwd;
+ bool lateral_rev;
+ Relids join_lateral_rels;
- if (bms_is_subset(ljinfo->lateral_rhs, rel2->relids) &&
- bms_overlap(ljinfo->lateral_lhs, rel1->relids))
+ /*
+ * The proposed rels could each contain lateral references to the
+ * other, in which case the join is impossible. If there are lateral
+ * references in just one direction, then the join has to be done with
+ * a nestloop with the lateral referencer on the inside. If the join
+ * matches an SJ that cannot be implemented by such a nestloop, the
+ * join is impossible.
+ *
+ * Also, if the lateral reference is only indirect, we should reject
+ * the join; whatever rel(s) the reference chain goes through must be
+ * joined to first.
+ *
+ * Another case that might keep us from building a valid plan is the
+ * implementation restriction described by have_dangerous_phv().
+ */
+ lateral_fwd = bms_overlap(rel1->relids, rel2->lateral_relids);
+ lateral_rev = bms_overlap(rel2->relids, rel1->lateral_relids);
+ if (lateral_fwd && lateral_rev)
+ return false; /* have lateral refs in both directions */
+ if (lateral_fwd)
{
/* has to be implemented as nestloop with rel1 on left */
- if (lateral_rev)
- return false; /* have lateral refs in both directions */
- lateral_fwd = true;
- if (!bms_is_subset(ljinfo->lateral_lhs, rel1->relids))
- return false; /* rel1 can't compute the required parameter */
if (match_sjinfo &&
(reversed ||
unique_ified ||
match_sjinfo->jointype == JOIN_FULL))
return false; /* not implementable as nestloop */
+ /* check there is a direct reference from rel2 to rel1 */
+ foreach(l, root->lateral_info_list)
+ {
+ LateralJoinInfo *ljinfo = (LateralJoinInfo *) lfirst(l);
+
+ if (bms_is_subset(ljinfo->lateral_rhs, rel2->relids) &&
+ bms_is_subset(ljinfo->lateral_lhs, rel1->relids))
+ break;
+ }
+ if (l == NULL)
+ return false; /* only indirect refs, so reject */
+ /* check we won't have a dangerous PHV */
+ if (have_dangerous_phv(root, rel1->relids, rel2->lateral_relids))
+ return false; /* might be unable to handle required PHV */
}
- if (bms_is_subset(ljinfo->lateral_rhs, rel1->relids) &&
- bms_overlap(ljinfo->lateral_lhs, rel2->relids))
+ else if (lateral_rev)
{
/* has to be implemented as nestloop with rel2 on left */
- if (lateral_fwd)
- return false; /* have lateral refs in both directions */
- lateral_rev = true;
- if (!bms_is_subset(ljinfo->lateral_lhs, rel2->relids))
- return false; /* rel2 can't compute the required parameter */
if (match_sjinfo &&
(!reversed ||
unique_ified ||
match_sjinfo->jointype == JOIN_FULL))
return false; /* not implementable as nestloop */
+ /* check there is a direct reference from rel1 to rel2 */
+ foreach(l, root->lateral_info_list)
+ {
+ LateralJoinInfo *ljinfo = (LateralJoinInfo *) lfirst(l);
+
+ if (bms_is_subset(ljinfo->lateral_rhs, rel1->relids) &&
+ bms_is_subset(ljinfo->lateral_lhs, rel2->relids))
+ break;
+ }
+ if (l == NULL)
+ return false; /* only indirect refs, so reject */
+ /* check we won't have a dangerous PHV */
+ if (have_dangerous_phv(root, rel2->relids, rel1->lateral_relids))
+ return false; /* might be unable to handle required PHV */
}
- }
- /*
- * LATERAL references could also cause problems later on if we accept this
- * join: if the join's minimum parameterization includes any rels that
- * would have to be on the inside of an outer join with this join rel,
- * then it's never going to be possible to build the complete query using
- * this join. We should reject this join not only because it'll save
- * work, but because if we don't, the clauseless-join heuristics might
- * think that legality of this join means that some other join rel need
- * not be formed, and that could lead to failure to find any plan at all.
- * It seems best not to merge this check into the main loop above, because
- * it is concerned with SJs that are not otherwise relevant to this join.
- */
- join_lateral_rels = min_join_parameterization(root, joinrelids);
- if (join_lateral_rels)
- {
- foreach(l, root->join_info_list)
+ /*
+ * LATERAL references could also cause problems later on if we accept
+ * this join: if the join's minimum parameterization includes any rels
+ * that would have to be on the inside of an outer join with this join
+ * rel, then it's never going to be possible to build the complete
+ * query using this join. We should reject this join not only because
+ * it'll save work, but because if we don't, the clauseless-join
+ * heuristics might think that legality of this join means that some
+ * other join rel need not be formed, and that could lead to failure
+ * to find any plan at all. We have to consider not only rels that
+ * are directly on the inner side of an OJ with the joinrel, but also
+ * ones that are indirectly so, so search to find all such rels.
+ */
+ join_lateral_rels = min_join_parameterization(root, joinrelids,
+ rel1, rel2);
+ if (join_lateral_rels)
{
- SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
-
- if (bms_overlap(sjinfo->min_righthand, join_lateral_rels) &&
- bms_overlap(sjinfo->min_lefthand, joinrelids))
- return false; /* will not be able to join to min_righthand */
- if (sjinfo->jointype == JOIN_FULL &&
- bms_overlap(sjinfo->min_lefthand, join_lateral_rels) &&
- bms_overlap(sjinfo->min_righthand, joinrelids))
- return false; /* will not be able to join to min_lefthand */
+ Relids join_plus_rhs = bms_copy(joinrelids);
+ bool more;
+
+ do
+ {
+ more = false;
+ foreach(l, root->join_info_list)
+ {
+ SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
+
+ if (bms_overlap(sjinfo->min_lefthand, join_plus_rhs) &&
+ !bms_is_subset(sjinfo->min_righthand, join_plus_rhs))
+ {
+ join_plus_rhs = bms_add_members(join_plus_rhs,
+ sjinfo->min_righthand);
+ more = true;
+ }
+ /* full joins constrain both sides symmetrically */
+ if (sjinfo->jointype == JOIN_FULL &&
+ bms_overlap(sjinfo->min_righthand, join_plus_rhs) &&
+ !bms_is_subset(sjinfo->min_lefthand, join_plus_rhs))
+ {
+ join_plus_rhs = bms_add_members(join_plus_rhs,
+ sjinfo->min_lefthand);
+ more = true;
+ }
+ }
+ } while (more);
+ if (bms_overlap(join_plus_rhs, join_lateral_rels))
+ return false; /* will not be able to join to some RHS rel */
}
}
@@ -852,8 +900,9 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
* could be merged with that function, but it seems clearer to separate the
* two concerns. We need this test because there are degenerate cases where
* a clauseless join must be performed to satisfy join-order restrictions.
- * Also, if one rel has a lateral reference to the other, we should consider
- * joining them even if the join would be clauseless.
+ * Also, if one rel has a lateral reference to the other, or both are needed
+ * to compute some PHV, we should consider joining them even if the join would
+ * be clauseless.
*
* Note: this is only a problem if one side of a degenerate outer join
* contains multiple rels, or a clauseless join is required within an
@@ -870,8 +919,8 @@ have_join_order_restriction(PlannerInfo *root,
ListCell *l;
/*
- * If either side has a lateral reference to the other, attempt the join
- * regardless of outer-join considerations.
+ * If either side has a direct lateral reference to the other, attempt the
+ * join regardless of outer-join considerations.
*/
foreach(l, root->lateral_info_list)
{
@@ -885,6 +934,22 @@ have_join_order_restriction(PlannerInfo *root,
return true;
}
+ /*
+ * Likewise, if both rels are needed to compute some PlaceHolderVar,
+ * attempt the join regardless of outer-join considerations. (This is not
+ * very desirable, because a PHV with a large eval_at set will cause a lot
+ * of probably-useless joins to be considered, but failing to do this can
+ * cause us to fail to construct a plan at all.)
+ */
+ foreach(l, root->placeholder_list)
+ {
+ PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
+
+ if (bms_is_subset(rel1->relids, phinfo->ph_eval_at) &&
+ bms_is_subset(rel2->relids, phinfo->ph_eval_at))
+ return true;
+ }
+
/*
* It's possible that the rels correspond to the left and right sides of a
* degenerate outer join, that is, one with no joinclause mentioning the
@@ -960,7 +1025,7 @@ have_join_order_restriction(PlannerInfo *root,
* has_join_restriction
* Detect whether the specified relation has join-order restrictions,
* due to being inside an outer join or an IN (sub-SELECT),
- * or participating in any LATERAL references.
+ * or participating in any LATERAL references or multi-rel PHVs.
*
* Essentially, this tests whether have_join_order_restriction() could
* succeed with this rel and some other one. It's OK if we sometimes
@@ -972,12 +1037,15 @@ has_join_restriction(PlannerInfo *root, RelOptInfo *rel)
{
ListCell *l;
- foreach(l, root->lateral_info_list)
+ if (rel->lateral_relids != NULL || rel->lateral_referencers != NULL)
+ return true;
+
+ foreach(l, root->placeholder_list)
{
- LateralJoinInfo *ljinfo = (LateralJoinInfo *) lfirst(l);
+ PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
- if (bms_is_subset(ljinfo->lateral_rhs, rel->relids) ||
- bms_overlap(ljinfo->lateral_lhs, rel->relids))
+ if (bms_is_subset(rel->relids, phinfo->ph_eval_at) &&
+ !bms_equal(rel->relids, phinfo->ph_eval_at))
return true;
}
@@ -1058,6 +1126,57 @@ has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel)
}
+/*
+ * There's a pitfall for creating parameterized nestloops: suppose the inner
+ * rel (call it A) has a parameter that is a PlaceHolderVar, and that PHV's
+ * minimum eval_at set includes the outer rel (B) and some third rel (C).
+ * We might think we could create a B/A nestloop join that's parameterized by
+ * C. But we would end up with a plan in which the PHV's expression has to be
+ * evaluated as a nestloop parameter at the B/A join; and the executor is only
+ * set up to handle simple Vars as NestLoopParams. Rather than add complexity
+ * and overhead to the executor for such corner cases, it seems better to
+ * forbid the join. (Note that we can still make use of A's parameterized
+ * path with pre-joined B+C as the outer rel. have_join_order_restriction()
+ * ensures that we will consider making such a join even if there are not
+ * other reasons to do so.)
+ *
+ * So we check whether any PHVs used in the query could pose such a hazard.
+ * We don't have any simple way of checking whether a risky PHV would actually
+ * be used in the inner plan, and the case is so unusual that it doesn't seem
+ * worth working very hard on it.
+ *
+ * This needs to be checked in two places. If the inner rel's minimum
+ * parameterization would trigger the restriction, then join_is_legal() should
+ * reject the join altogether, because there will be no workable paths for it.
+ * But joinpath.c has to check again for every proposed nestloop path, because
+ * the inner path might have more than the minimum parameterization, causing
+ * some PHV to be dangerous for it that otherwise wouldn't be.
+ */
+bool
+have_dangerous_phv(PlannerInfo *root,
+ Relids outer_relids, Relids inner_params)
+{
+ ListCell *lc;
+
+ foreach(lc, root->placeholder_list)
+ {
+ PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
+
+ if (!bms_is_subset(phinfo->ph_eval_at, inner_params))
+ continue; /* ignore, could not be a nestloop param */
+ if (!bms_overlap(phinfo->ph_eval_at, outer_relids))
+ continue; /* ignore, not relevant to this join */
+ if (bms_is_subset(phinfo->ph_eval_at, outer_relids))
+ continue; /* safe, it can be eval'd within outerrel */
+ /* Otherwise, it's potentially unsafe, so reject the join */
+ return true;
+ }
+
+ /* OK to perform the join */
+ return false;
+}
+
+
/*
* is_dummy_rel --- has relation been proven empty?
*/
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 2f4e8181eb5a70bc4183ec9270c2215acf9f8d4e..dded896064d05667832cbf353527b4a51ab95703 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -449,9 +449,7 @@ create_lateral_join_info(PlannerInfo *root)
Assert(false);
}
- /* We now know all the relids needed for lateral refs in this rel */
- if (bms_is_empty(lateral_relids))
- continue; /* ensure lateral_relids is NULL if empty */
+ /* We now have all the direct lateral refs from this rel */
brel->lateral_relids = lateral_relids;
}
@@ -459,6 +457,14 @@ create_lateral_join_info(PlannerInfo *root)
* Now check for lateral references within PlaceHolderVars, and make
* LateralJoinInfos describing each such reference. Unlike references in
* unflattened LATERAL RTEs, the referencing location could be a join.
+ *
+ * For a PHV that is due to be evaluated at a join, we mark each of the
+ * join's member baserels as having the PHV's lateral references too. Even
+ * though the baserels could be scanned without considering those lateral
+ * refs, we will never be able to form the join except as a path
+ * parameterized by the lateral refs, so there is no point in considering
+ * unparameterized paths for the baserels; and we mustn't try to join any
+ * of those baserels to the lateral refs too soon, either.
*/
foreach(lc, root->placeholder_list)
{
@@ -471,6 +477,7 @@ create_lateral_join_info(PlannerInfo *root)
PVC_RECURSE_AGGREGATES,
PVC_INCLUDE_PLACEHOLDERS);
ListCell *lc2;
+ int ev_at;
foreach(lc2, vars)
{
@@ -500,6 +507,15 @@ create_lateral_join_info(PlannerInfo *root)
}
list_free(vars);
+
+ ev_at = -1;
+ while ((ev_at = bms_next_member(eval_at, ev_at)) >= 0)
+ {
+ RelOptInfo *brel = find_base_rel(root, ev_at);
+
+ brel->lateral_relids = bms_add_members(brel->lateral_relids,
+ phinfo->ph_lateral);
+ }
}
}
@@ -508,46 +524,103 @@ create_lateral_join_info(PlannerInfo *root)
return;
/*
- * Now that we've identified all lateral references, make a second pass in
- * which we mark each baserel with the set of relids of rels that
- * reference it laterally (essentially, the inverse mapping of
- * lateral_relids). We'll need this for join_clause_is_movable_to().
+ * At this point the lateral_relids sets represent only direct lateral
+ * references. Replace them by their transitive closure, so that they
+ * describe both direct and indirect lateral references. If relation X
+ * references Y laterally, and Y references Z laterally, then we will have
+ * to scan X on the inside of a nestloop with Z, so for all intents and
+ * purposes X is laterally dependent on Z too.
*
- * Also, propagate lateral_relids and lateral_referencers from appendrel
- * parent rels to their child rels. We intentionally give each child rel
- * the same minimum parameterization, even though it's quite possible that
- * some don't reference all the lateral rels. This is because any append
- * path for the parent will have to have the same parameterization for
- * every child anyway, and there's no value in forcing extra
- * reparameterize_path() calls. Similarly, a lateral reference to the
- * parent prevents use of otherwise-movable join rels for each child.
+ * This code is essentially Warshall's algorithm for transitive closure.
+ * The outer loop considers each baserel, and propagates its lateral
+ * dependencies to those baserels that have a lateral dependency on it.
*/
for (rti = 1; rti < root->simple_rel_array_size; rti++)
{
RelOptInfo *brel = root->simple_rel_array[rti];
- Relids lateral_referencers;
+ Relids outer_lateral_relids;
+ Index rti2;
- if (brel == NULL)
+ if (brel == NULL || brel->reloptkind != RELOPT_BASEREL)
continue;
- if (brel->reloptkind != RELOPT_BASEREL)
+
+ /* need not consider baserel further if it has no lateral refs */
+ outer_lateral_relids = brel->lateral_relids;
+ if (outer_lateral_relids == NULL)
continue;
- /* Compute lateral_referencers using the finished lateral_info_list */
- lateral_referencers = NULL;
- foreach(lc, root->lateral_info_list)
+ /* else scan all baserels */
+ for (rti2 = 1; rti2 < root->simple_rel_array_size; rti2++)
{
- LateralJoinInfo *ljinfo = (LateralJoinInfo *) lfirst(lc);
+ RelOptInfo *brel2 = root->simple_rel_array[rti2];
+
+ if (brel2 == NULL || brel2->reloptkind != RELOPT_BASEREL)
+ continue;
- if (bms_is_member(brel->relid, ljinfo->lateral_lhs))
- lateral_referencers = bms_add_members(lateral_referencers,
- ljinfo->lateral_rhs);
+ /* if brel2 has lateral ref to brel, propagate brel's refs */
+ if (bms_is_member(rti, brel2->lateral_relids))
+ brel2->lateral_relids = bms_add_members(brel2->lateral_relids,
+ outer_lateral_relids);
}
- brel->lateral_referencers = lateral_referencers;
+ }
+
+ /*
+ * Now that we've identified all lateral references, mark each baserel
+ * with the set of relids of rels that reference it laterally (possibly
+ * indirectly) --- that is, the inverse mapping of lateral_relids.
+ */
+ for (rti = 1; rti < root->simple_rel_array_size; rti++)
+ {
+ RelOptInfo *brel = root->simple_rel_array[rti];
+ Relids lateral_relids;
+ int rti2;
+
+ if (brel == NULL || brel->reloptkind != RELOPT_BASEREL)
+ continue;
+
+ /* Nothing to do at rels with no lateral refs */
+ lateral_relids = brel->lateral_relids;
+ if (lateral_relids == NULL)
+ continue;
/*
- * If it's an appendrel parent, copy its lateral_relids and
- * lateral_referencers to each child rel.
+ * We should not have broken the invariant that lateral_relids is
+ * exactly NULL if empty.
*/
+ Assert(!bms_is_empty(lateral_relids));
+
+ /* Also, no rel should have a lateral dependency on itself */
+ Assert(!bms_is_member(rti, lateral_relids));
+
+ /* Mark this rel's referencees */
+ rti2 = -1;
+ while ((rti2 = bms_next_member(lateral_relids, rti2)) >= 0)
+ {
+ RelOptInfo *brel2 = root->simple_rel_array[rti2];
+
+ Assert(brel2 != NULL && brel2->reloptkind == RELOPT_BASEREL);
+ brel2->lateral_referencers =
+ bms_add_member(brel2->lateral_referencers, rti);
+ }
+ }
+
+ /*
+ * Lastly, propagate lateral_relids and lateral_referencers from appendrel
+ * parent rels to their child rels. We intentionally give each child rel
+ * the same minimum parameterization, even though it's quite possible that
+ * some don't reference all the lateral rels. This is because any append
+ * path for the parent will have to have the same parameterization for
+ * every child anyway, and there's no value in forcing extra
+ * reparameterize_path() calls. Similarly, a lateral reference to the
+ * parent prevents use of otherwise-movable join rels for each child.
+ */
+ for (rti = 1; rti < root->simple_rel_array_size; rti++)
+ {
+ RelOptInfo *brel = root->simple_rel_array[rti];
+
+ if (brel == NULL || brel->reloptkind != RELOPT_BASEREL)
+ continue;
+
if (root->simple_rte_array[rti]->inh)
{
foreach(lc, root->append_rel_list)
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index b197f144117f3b0e479919f33c203266c55b89b7..a2be2ede85e1dbf6512137bd59156e9a47f33908 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -373,7 +373,8 @@ build_join_rel(PlannerInfo *root,
joinrel->cheapest_total_path = NULL;
joinrel->cheapest_unique_path = NULL;
joinrel->cheapest_parameterized_paths = NIL;
- joinrel->lateral_relids = min_join_parameterization(root, joinrel->relids);
+ joinrel->lateral_relids = min_join_parameterization(root, joinrel->relids,
+ outer_rel, inner_rel);
joinrel->relid = 0; /* indicates not a baserel */
joinrel->rtekind = RTE_JOIN;
joinrel->min_attr = 0;
@@ -508,29 +509,27 @@ build_join_rel(PlannerInfo *root,
* because join_is_legal() needs the value to check a prospective join.
*/
Relids
-min_join_parameterization(PlannerInfo *root, Relids joinrelids)
+min_join_parameterization(PlannerInfo *root,
+ Relids joinrelids,
+ RelOptInfo *outer_rel,
+ RelOptInfo *inner_rel)
{
Relids result;
- ListCell *lc;
-
- /* Easy if there are no lateral references */
- if (root->lateral_info_list == NIL)
- return NULL;
/*
- * Scan lateral_info_list to find all the lateral references occurring in
- * or below this join.
+ * Basically we just need the union of the inputs' lateral_relids, less
+ * whatever is already in the join.
+ *
+ * It's not immediately obvious that this is a valid way to compute the
+ * result, because it might seem that we're ignoring possible lateral refs
+ * of PlaceHolderVars that are due to be computed at the join but not in
+ * either input. However, because create_lateral_join_info() already
+ * charged all such PHV refs to each member baserel of the join, they'll
+ * be accounted for already in the inputs' lateral_relids. Likewise, we
+ * do not need to worry about doing transitive closure here, because that
+ * was already accounted for in the original baserel lateral_relids.
*/
- result = NULL;
- foreach(lc, root->lateral_info_list)
- {
- LateralJoinInfo *ljinfo = (LateralJoinInfo *) lfirst(lc);
-
- if (bms_is_subset(ljinfo->lateral_rhs, joinrelids))
- result = bms_add_members(result, ljinfo->lateral_lhs);
- }
-
- /* Remove any rels that are already included in the join */
+ result = bms_union(outer_rel->lateral_relids, inner_rel->lateral_relids);
result = bms_del_members(result, joinrelids);
/* Maintain invariant that result is exactly NULL if empty */
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 32321238ae4c4f6b8412de17cd65ad5f95ef3dc8..f7796f8efbeaef07ccff4ef65793d52772da3508 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -358,6 +358,7 @@ typedef struct PlannerInfo
* cheapest_parameterized_paths - best paths for their parameterizations;
* always includes cheapest_total_path, even if that's unparameterized
* lateral_relids - required outer rels for LATERAL, as a Relids set
+ * (includes both direct and indirect lateral references)
*
* If the relation is a base relation it will have these fields set:
*
@@ -373,6 +374,7 @@ typedef struct PlannerInfo
* lateral_vars - lateral cross-references of rel, if any (list of
* Vars and PlaceHolderVars)
* lateral_referencers - relids of rels that reference this one laterally
+ * (includes both direct and indirect lateral references)
* indexlist - list of IndexOptInfo nodes for relation's indexes
* (always NIL if it's not a table)
* pages - number of disk pages in relation (zero if not a table)
diff --git a/src/include/optimizer/pathnode.h b/src/include/optimizer/pathnode.h
index f41847f4093ba19bb11cb97fa71a2265a1810ed0..8fb9eda01b67e2b529124f41f9a50117f05a48a0 100644
--- a/src/include/optimizer/pathnode.h
+++ b/src/include/optimizer/pathnode.h
@@ -148,7 +148,10 @@ extern RelOptInfo *build_join_rel(PlannerInfo *root,
RelOptInfo *inner_rel,
SpecialJoinInfo *sjinfo,
List **restrictlist_ptr);
-extern Relids min_join_parameterization(PlannerInfo *root, Relids joinrelids);
+extern Relids min_join_parameterization(PlannerInfo *root,
+ Relids joinrelids,
+ RelOptInfo *outer_rel,
+ RelOptInfo *inner_rel);
extern RelOptInfo *build_empty_join_rel(PlannerInfo *root);
extern AppendRelInfo *find_childrel_appendrelinfo(PlannerInfo *root,
RelOptInfo *rel);
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 87123a57295d271f9b69a7581190721f31e41ace..7757741c10467ad621f5be3d13ae086f4b8144e3 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -98,6 +98,8 @@ extern RelOptInfo *make_join_rel(PlannerInfo *root,
RelOptInfo *rel1, RelOptInfo *rel2);
extern bool have_join_order_restriction(PlannerInfo *root,
RelOptInfo *rel1, RelOptInfo *rel2);
+extern bool have_dangerous_phv(PlannerInfo *root,
+ Relids outer_relids, Relids inner_params);
/*
* equivclass.c
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index dba5d2dbab383c2e4578fea12324982bd279ceb1..64f046ee0bb83235cc7708eee24893411b08a1f4 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -3620,6 +3620,159 @@ where t1.f1 = ss.f1;
doh! | 4567890123456789 | 123 | 4567890123456789 | doh!
(1 row)
+explain (verbose, costs off)
+select * from
+ text_tbl t1
+ left join int8_tbl i8
+ on i8.q2 = 123,
+ lateral (select i8.q1, t2.f1 from text_tbl t2 limit 1) as ss1,
+ lateral (select ss1.* from text_tbl t3 limit 1) as ss2
+where t1.f1 = ss2.f1;
+ QUERY PLAN
+-------------------------------------------------------------------
+ Nested Loop
+ Output: t1.f1, i8.q1, i8.q2, (i8.q1), t2.f1, ((i8.q1)), (t2.f1)
+ Join Filter: (t1.f1 = (t2.f1))
+ -> Nested Loop
+ Output: t1.f1, i8.q1, i8.q2, (i8.q1), t2.f1
+ -> Nested Loop Left Join
+ Output: t1.f1, i8.q1, i8.q2
+ -> Seq Scan on public.text_tbl t1
+ Output: t1.f1
+ -> Materialize
+ Output: i8.q1, i8.q2
+ -> Seq Scan on public.int8_tbl i8
+ Output: i8.q1, i8.q2
+ Filter: (i8.q2 = 123)
+ -> Limit
+ Output: (i8.q1), t2.f1
+ -> Seq Scan on public.text_tbl t2
+ Output: i8.q1, t2.f1
+ -> Limit
+ Output: ((i8.q1)), (t2.f1)
+ -> Seq Scan on public.text_tbl t3
+ Output: (i8.q1), t2.f1
+(22 rows)
+
+select * from
+ text_tbl t1
+ left join int8_tbl i8
+ on i8.q2 = 123,
+ lateral (select i8.q1, t2.f1 from text_tbl t2 limit 1) as ss1,
+ lateral (select ss1.* from text_tbl t3 limit 1) as ss2
+where t1.f1 = ss2.f1;
+ f1 | q1 | q2 | q1 | f1 | q1 | f1
+------+------------------+-----+------------------+------+------------------+------
+ doh! | 4567890123456789 | 123 | 4567890123456789 | doh! | 4567890123456789 | doh!
+(1 row)
+
+explain (verbose, costs off)
+select 1 from
+ text_tbl as tt1
+ inner join text_tbl as tt2 on (tt1.f1 = 'foo')
+ left join text_tbl as tt3 on (tt3.f1 = 'foo')
+ left join text_tbl as tt4 on (tt3.f1 = tt4.f1),
+ lateral (select tt4.f1 as c0 from text_tbl as tt5 limit 1) as ss1
+where tt1.f1 = ss1.c0;
+ QUERY PLAN
+----------------------------------------------------------
+ Nested Loop
+ Output: 1
+ -> Nested Loop Left Join
+ Output: tt1.f1, tt4.f1
+ -> Nested Loop
+ Output: tt1.f1
+ -> Seq Scan on public.text_tbl tt1
+ Output: tt1.f1
+ Filter: (tt1.f1 = 'foo'::text)
+ -> Seq Scan on public.text_tbl tt2
+ Output: tt2.f1
+ -> Materialize
+ Output: tt4.f1
+ -> Nested Loop Left Join
+ Output: tt4.f1
+ Join Filter: (tt3.f1 = tt4.f1)
+ -> Seq Scan on public.text_tbl tt3
+ Output: tt3.f1
+ Filter: (tt3.f1 = 'foo'::text)
+ -> Seq Scan on public.text_tbl tt4
+ Output: tt4.f1
+ Filter: (tt4.f1 = 'foo'::text)
+ -> Subquery Scan on ss1
+ Output: ss1.c0
+ Filter: (ss1.c0 = 'foo'::text)
+ -> Limit
+ Output: (tt4.f1)
+ -> Seq Scan on public.text_tbl tt5
+ Output: tt4.f1
+(29 rows)
+
+select 1 from
+ text_tbl as tt1
+ inner join text_tbl as tt2 on (tt1.f1 = 'foo')
+ left join text_tbl as tt3 on (tt3.f1 = 'foo')
+ left join text_tbl as tt4 on (tt3.f1 = tt4.f1),
+ lateral (select tt4.f1 as c0 from text_tbl as tt5 limit 1) as ss1
+where tt1.f1 = ss1.c0;
+ ?column?
+----------
+(0 rows)
+
+--
+-- check a case in which a PlaceHolderVar forces join order
+--
+explain (verbose, costs off)
+select ss2.* from
+ int4_tbl i41
+ left join int8_tbl i8
+ join (select i42.f1 as c1, i43.f1 as c2, 42 as c3
+ from int4_tbl i42, int4_tbl i43) ss1
+ on i8.q1 = ss1.c2
+ on i41.f1 = ss1.c1,
+ lateral (select i41.*, i8.*, ss1.* from text_tbl limit 1) ss2
+where ss1.c2 = 0;
+ QUERY PLAN
+------------------------------------------------------------------------
+ Nested Loop
+ Output: (i41.f1), (i8.q1), (i8.q2), (i42.f1), (i43.f1), ((42))
+ -> Hash Join
+ Output: i41.f1, i42.f1, i8.q1, i8.q2, i43.f1, 42
+ Hash Cond: (i41.f1 = i42.f1)
+ -> Nested Loop
+ Output: i8.q1, i8.q2, i43.f1, i41.f1
+ -> Nested Loop
+ Output: i8.q1, i8.q2, i43.f1
+ -> Seq Scan on public.int8_tbl i8
+ Output: i8.q1, i8.q2
+ Filter: (i8.q1 = 0)
+ -> Seq Scan on public.int4_tbl i43
+ Output: i43.f1
+ Filter: (i43.f1 = 0)
+ -> Seq Scan on public.int4_tbl i41
+ Output: i41.f1
+ -> Hash
+ Output: i42.f1
+ -> Seq Scan on public.int4_tbl i42
+ Output: i42.f1
+ -> Limit
+ Output: (i41.f1), (i8.q1), (i8.q2), (i42.f1), (i43.f1), ((42))
+ -> Seq Scan on public.text_tbl
+ Output: i41.f1, i8.q1, i8.q2, i42.f1, i43.f1, (42)
+(25 rows)
+
+select ss2.* from
+ int4_tbl i41
+ left join int8_tbl i8
+ join (select i42.f1 as c1, i43.f1 as c2, 42 as c3
+ from int4_tbl i42, int4_tbl i43) ss1
+ on i8.q1 = ss1.c2
+ on i41.f1 = ss1.c1,
+ lateral (select i41.*, i8.*, ss1.* from text_tbl limit 1) ss2
+where ss1.c2 = 0;
+ f1 | q1 | q2 | c1 | c2 | c3
+----+----+----+----+----+----
+(0 rows)
+
--
-- test ability to push constants through outer join clauses
--
@@ -4741,14 +4894,12 @@ select * from
Output: a.q1, a.q2
-> Nested Loop
Output: b.q1, c.q1, LEAST(a.q1, b.q1, c.q1)
- Join Filter: (a.q2 = b.q1)
-> Seq Scan on public.int8_tbl b
Output: b.q1, b.q2
- -> Materialize
- Output: c.q1
- -> Seq Scan on public.int8_tbl c
- Output: c.q1
-(13 rows)
+ Filter: (a.q2 = b.q1)
+ -> Seq Scan on public.int8_tbl c
+ Output: c.q1, c.q2
+(11 rows)
select * from
int8_tbl a left join lateral
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index fdd4e78cf281da3a009fcc5b1daebceef2aabf5a..0358d00e4045055dae952686bfd19a1a204014f6 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -1134,6 +1134,65 @@ select * from
lateral (select i8.q1, t2.f1 from text_tbl t2 limit 1) as ss
where t1.f1 = ss.f1;
+explain (verbose, costs off)
+select * from
+ text_tbl t1
+ left join int8_tbl i8
+ on i8.q2 = 123,
+ lateral (select i8.q1, t2.f1 from text_tbl t2 limit 1) as ss1,
+ lateral (select ss1.* from text_tbl t3 limit 1) as ss2
+where t1.f1 = ss2.f1;
+
+select * from
+ text_tbl t1
+ left join int8_tbl i8
+ on i8.q2 = 123,
+ lateral (select i8.q1, t2.f1 from text_tbl t2 limit 1) as ss1,
+ lateral (select ss1.* from text_tbl t3 limit 1) as ss2
+where t1.f1 = ss2.f1;
+
+explain (verbose, costs off)
+select 1 from
+ text_tbl as tt1
+ inner join text_tbl as tt2 on (tt1.f1 = 'foo')
+ left join text_tbl as tt3 on (tt3.f1 = 'foo')
+ left join text_tbl as tt4 on (tt3.f1 = tt4.f1),
+ lateral (select tt4.f1 as c0 from text_tbl as tt5 limit 1) as ss1
+where tt1.f1 = ss1.c0;
+
+select 1 from
+ text_tbl as tt1
+ inner join text_tbl as tt2 on (tt1.f1 = 'foo')
+ left join text_tbl as tt3 on (tt3.f1 = 'foo')
+ left join text_tbl as tt4 on (tt3.f1 = tt4.f1),
+ lateral (select tt4.f1 as c0 from text_tbl as tt5 limit 1) as ss1
+where tt1.f1 = ss1.c0;
+
+--
+-- check a case in which a PlaceHolderVar forces join order
+--
+
+explain (verbose, costs off)
+select ss2.* from
+ int4_tbl i41
+ left join int8_tbl i8
+ join (select i42.f1 as c1, i43.f1 as c2, 42 as c3
+ from int4_tbl i42, int4_tbl i43) ss1
+ on i8.q1 = ss1.c2
+ on i41.f1 = ss1.c1,
+ lateral (select i41.*, i8.*, ss1.* from text_tbl limit 1) ss2
+where ss1.c2 = 0;
+
+select ss2.* from
+ int4_tbl i41
+ left join int8_tbl i8
+ join (select i42.f1 as c1, i43.f1 as c2, 42 as c3
+ from int4_tbl i42, int4_tbl i43) ss1
+ on i8.q1 = ss1.c2
+ on i41.f1 = ss1.c1,
+ lateral (select i41.*, i8.*, ss1.* from text_tbl limit 1) ss2
+where ss1.c2 = 0;
+
--
-- test ability to push constants through outer join clauses
--