expr,
true,
false,
+ false,
+ false,
root->qual_security_level,
grouped_rel->relids,
+ NULL,
NULL);
if (is_foreign_expr(root, grouped_rel, expr))
fpinfo->remote_conds = lappend(fpinfo->remote_conds, rinfo);
if we form B/C after A/B, then both forms of the clause are applicable
so far as that test can tell. We have to look more closely to notice
that the "Pbc" clause form refers to relation B which is no longer
-directly accessible. While this check is straightforward, it's not
-especially cheap (see clause_is_computable_at()). To avoid doing it
-unnecessarily, we mark the variant versions of a redundant clause as
-either "has_clone" or "is_clone". When considering a clone clause,
-we must check clause_is_computable_at() to disentangle which version
-to apply at the current join level. (In debug builds, we also Assert
-that non-clone clauses are validly computable at the current level;
-but that seems too expensive for production usage.)
+directly accessible. While such a check could be performed using the
+per-relation RelOptInfo.nulling_relids data, it would be annoyingly
+expensive to do over and over as we consider different join paths.
+To make this simple and reliable, we compute an "incompatible_relids"
+set for each variant version (clone) of a redundant clause. A clone
+clause should not be applied if any of the outer-join relids listed in
+incompatible_relids has already been computed below the current join.
Optimizer Functions
make_restrictinfo(root,
(Expr *) ntest,
restrictinfo->is_pushed_down,
+ restrictinfo->has_clone,
+ restrictinfo->is_clone,
restrictinfo->pseudoconstant,
restrictinfo->security_level,
NULL,
+ restrictinfo->incompatible_relids,
restrictinfo->outer_relids);
}
return false;
* clause into the regular processing, because otherwise the join will be
* seen as a clauseless join and avoided during join order searching.
* We handle this by generating a constant-TRUE clause that is marked with
- * required_relids that make it a join between the correct relations.
+ * the same required_relids etc as the removed outer-join clause, thus
+ * making it a join clause between the correct relations.
*/
void
reconsider_outer_join_clauses(PlannerInfo *root)
/* throw back a dummy replacement clause (see notes above) */
rinfo = make_restrictinfo(root,
(Expr *) makeBoolConst(true, false),
- true, /* is_pushed_down */
+ rinfo->is_pushed_down,
+ rinfo->has_clone,
+ rinfo->is_clone,
false, /* pseudoconstant */
0, /* security_level */
rinfo->required_relids,
+ rinfo->incompatible_relids,
rinfo->outer_relids);
distribute_restrictinfo_to_rels(root, rinfo);
}
/* throw back a dummy replacement clause (see notes above) */
rinfo = make_restrictinfo(root,
(Expr *) makeBoolConst(true, false),
- true, /* is_pushed_down */
+ rinfo->is_pushed_down,
+ rinfo->has_clone,
+ rinfo->is_clone,
false, /* pseudoconstant */
0, /* security_level */
rinfo->required_relids,
+ rinfo->incompatible_relids,
rinfo->outer_relids);
distribute_restrictinfo_to_rels(root, rinfo);
}
/* throw back a dummy replacement clause (see notes above) */
rinfo = make_restrictinfo(root,
(Expr *) makeBoolConst(true, false),
- true, /* is_pushed_down */
+ rinfo->is_pushed_down,
+ rinfo->has_clone,
+ rinfo->is_clone,
false, /* pseudoconstant */
0, /* security_level */
rinfo->required_relids,
+ rinfo->incompatible_relids,
rinfo->outer_relids);
distribute_restrictinfo_to_rels(root, rinfo);
}
Relids qualscope,
Relids ojscope,
Relids outerjoin_nonnullable,
+ Relids incompatible_relids,
bool allow_equivalence,
bool has_clone,
bool is_clone,
Relids qualscope,
Relids ojscope,
Relids outerjoin_nonnullable,
+ Relids incompatible_relids,
bool allow_equivalence,
bool has_clone,
bool is_clone,
jtitem,
NULL,
root->qual_security_level,
- jtitem->qualscope, NULL, NULL,
+ jtitem->qualscope,
+ NULL, NULL, NULL,
true, false, false,
NULL);
jtitem,
NULL,
root->qual_security_level,
- jtitem->qualscope, NULL, NULL,
+ jtitem->qualscope,
+ NULL, NULL, NULL,
true, false, false,
NULL);
}
root->qual_security_level,
jtitem->qualscope,
ojscope, jtitem->nonnullable_rels,
+ NULL, /* incompatible_relids */
true, /* allow_equivalence */
false, false, /* not clones */
postponed_oj_qual_list);
jtitem->qualscope,
jtitem->qualscope,
NULL,
+ NULL,
true,
false, false, /* not clones */
NULL);
{
Relids joins_above;
Relids joins_below;
+ Relids incompatible_joins;
Relids joins_so_far;
List *quals;
int save_last_rinfo_serial;
joins_below,
NULL);
+ /*
+ * We'll need to mark the lower versions of the quals as not safe to
+ * apply above not-yet-processed joins of the stack. This prevents
+ * possibly applying a cloned qual at the wrong join level.
+ */
+ incompatible_joins = bms_union(joins_below, joins_above);
+ incompatible_joins = bms_add_member(incompatible_joins,
+ sjinfo->ojrelid);
+
/*
* Each time we produce RestrictInfo(s) from these quals, reset the
* last_rinfo_serial counter, so that the RestrictInfos for the "same"
* relation B will appear nulled by the syntactically-upper OJ
* within the Pbc clause, but those of relation C will not. (In
* the notation used by optimizer/README, we're converting a qual
- * of the form Pbc to Pb*c.)
+ * of the form Pbc to Pb*c.) Of course, we must also remove that
+ * bit from the incompatible_joins value, else we'll make a qual
+ * that can't be placed anywhere.
*/
if (above_sjinfo)
+ {
quals = (List *)
add_nulling_relids((Node *) quals,
sjinfo->syn_lefthand,
bms_make_singleton(othersj->ojrelid));
+ incompatible_joins = bms_del_member(incompatible_joins,
+ othersj->ojrelid);
+ }
/* Compute qualscope and ojscope for this join level */
this_qualscope = bms_union(qualscope, joins_so_far);
root->qual_security_level,
this_qualscope,
this_ojscope, nonnullable_rels,
+ bms_copy(incompatible_joins),
allow_equivalence,
has_clone,
is_clone,
* Vars coming from the lower join's RHS. (Again, we are
* converting a qual of the form Pbc to Pb*c, but now we are
* putting back bits that were there in the parser output and were
- * temporarily stripped above.)
+ * temporarily stripped above.) Update incompatible_joins too.
*/
if (below_sjinfo)
+ {
quals = (List *)
add_nulling_relids((Node *) quals,
othersj->syn_righthand,
bms_make_singleton(othersj->ojrelid));
+ incompatible_joins = bms_del_member(incompatible_joins,
+ othersj->ojrelid);
+ }
/* ... and track joins processed so far */
joins_so_far = bms_add_member(joins_so_far, othersj->ojrelid);
root->qual_security_level,
qualscope,
ojscope, nonnullable_rels,
+ NULL, /* incompatible_relids */
true, /* allow_equivalence */
false, false, /* not clones */
NULL); /* no more postponement */
Relids qualscope,
Relids ojscope,
Relids outerjoin_nonnullable,
+ Relids incompatible_relids,
bool allow_equivalence,
bool has_clone,
bool is_clone,
qualscope,
ojscope,
outerjoin_nonnullable,
+ incompatible_relids,
allow_equivalence,
has_clone,
is_clone,
* base+OJ rels appearing on the outer (nonnullable) side of the join
* (for FULL JOIN this includes both sides of the join, and must in fact
* equal qualscope)
+ * 'incompatible_relids': the set of outer-join relid(s) that must not be
+ * computed below this qual. We only bother to compute this for
+ * "clone" quals, otherwise it can be left NULL.
* 'allow_equivalence': true if it's okay to convert clause into an
* EquivalenceClass
* 'has_clone': has_clone property to assign to the qual
Relids qualscope,
Relids ojscope,
Relids outerjoin_nonnullable,
+ Relids incompatible_relids,
bool allow_equivalence,
bool has_clone,
bool is_clone,
restrictinfo = make_restrictinfo(root,
(Expr *) clause,
is_pushed_down,
+ has_clone,
+ is_clone,
pseudoconstant,
security_level,
relids,
+ incompatible_relids,
outerjoin_nonnullable);
- /* Apply appropriate clone marking, too */
- restrictinfo->has_clone = has_clone;
- restrictinfo->is_clone = is_clone;
-
/*
* If it's a join clause, add vars used in the clause to targetlists of
* their relations, so that they will be emitted by the plan nodes that
restrictinfo = make_restrictinfo(root,
(Expr *) clause,
true, /* is_pushed_down */
+ false, /* !has_clone */
+ false, /* !is_clone */
pseudoconstant,
security_level,
relids,
+ NULL, /* incompatible_relids */
NULL); /* outer_relids */
/*
restrictinfo = make_restrictinfo(root,
clause,
true, /* is_pushed_down */
+ false, /* !has_clone */
+ false, /* !is_clone */
false, /* pseudoconstant */
security_level, /* security_level */
qualscope, /* required_relids */
+ NULL, /* incompatible_relids */
NULL); /* outer_relids */
/* Set mergejoinability/hashjoinability flags */
make_restrictinfo(root,
(Expr *) onecq,
rinfo->is_pushed_down,
+ rinfo->has_clone,
+ rinfo->is_clone,
pseudoconstant,
rinfo->security_level,
- NULL, NULL));
+ NULL, NULL, NULL));
/* track minimum security level among child quals */
cq_min_security = Min(cq_min_security, rinfo->security_level);
}
/* not likely that we'd see constants here, so no check */
childquals = lappend(childquals,
make_restrictinfo(root, qual,
- true, false,
+ true,
+ false, false,
+ false,
security_level,
- NULL, NULL));
+ NULL, NULL, NULL));
cq_min_security = Min(cq_min_security, security_level);
}
security_level++;
orclause,
true,
false,
+ false,
+ false,
join_or_rinfo->security_level,
NULL,
+ NULL,
NULL);
/*
Assert(!RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids));
if (!bms_is_subset(rinfo->required_relids, both_input_relids))
continue;
- if (!clause_is_computable_at(root, rinfo, both_input_relids))
+ if (bms_overlap(rinfo->incompatible_relids, both_input_relids))
continue;
}
else
{
/*
* For non-clone clauses, we just Assert it's OK. These might
- * be either join or filter clauses.
+ * be either join or filter clauses; if it's a join clause
+ * then it should not refer to the current join's output.
+ * (There is little point in checking incompatible_relids,
+ * because it'll be NULL.)
*/
-#ifdef USE_ASSERT_CHECKING
- if (RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
- Assert(clause_is_computable_at(root, rinfo,
- joinrel->relids));
- else
- {
- Assert(bms_is_subset(rinfo->required_relids,
- both_input_relids));
- Assert(clause_is_computable_at(root, rinfo,
- both_input_relids));
- }
-#endif
+ Assert(RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids) ||
+ bms_is_subset(rinfo->required_relids,
+ both_input_relids));
}
/*
Expr *clause,
Expr *orclause,
bool is_pushed_down,
+ bool has_clone,
+ bool is_clone,
bool pseudoconstant,
Index security_level,
Relids required_relids,
+ Relids incompatible_relids,
Relids outer_relids);
static Expr *make_sub_restrictinfos(PlannerInfo *root,
Expr *clause,
bool is_pushed_down,
+ bool has_clone,
+ bool is_clone,
bool pseudoconstant,
Index security_level,
Relids required_relids,
+ Relids incompatible_relids,
Relids outer_relids);
*
* Build a RestrictInfo node containing the given subexpression.
*
- * The is_pushed_down and pseudoconstant flags for the
+ * The is_pushed_down, has_clone, is_clone, and pseudoconstant flags for the
* RestrictInfo must be supplied by the caller, as well as the correct values
- * for security_level and outer_relids.
+ * for security_level, incompatible_relids, and outer_relids.
* required_relids can be NULL, in which case it defaults to the actual clause
* contents (i.e., clause_relids).
*
- * Note that there aren't options to set the has_clone and is_clone flags:
- * we always initialize those to false. There's just one place that wants
- * something different, so making all callers pass them seems inconvenient.
- *
* We initialize fields that depend only on the given subexpression, leaving
* others that depend on context (or may never be needed at all) to be filled
* later.
make_restrictinfo(PlannerInfo *root,
Expr *clause,
bool is_pushed_down,
+ bool has_clone,
+ bool is_clone,
bool pseudoconstant,
Index security_level,
Relids required_relids,
+ Relids incompatible_relids,
Relids outer_relids)
{
/*
return (RestrictInfo *) make_sub_restrictinfos(root,
clause,
is_pushed_down,
+ has_clone,
+ is_clone,
pseudoconstant,
security_level,
required_relids,
+ incompatible_relids,
outer_relids);
/* Shouldn't be an AND clause, else AND/OR flattening messed up */
clause,
NULL,
is_pushed_down,
+ has_clone,
+ is_clone,
pseudoconstant,
security_level,
required_relids,
+ incompatible_relids,
outer_relids);
}
Expr *clause,
Expr *orclause,
bool is_pushed_down,
+ bool has_clone,
+ bool is_clone,
bool pseudoconstant,
Index security_level,
Relids required_relids,
+ Relids incompatible_relids,
Relids outer_relids)
{
RestrictInfo *restrictinfo = makeNode(RestrictInfo);
restrictinfo->orclause = orclause;
restrictinfo->is_pushed_down = is_pushed_down;
restrictinfo->pseudoconstant = pseudoconstant;
- restrictinfo->has_clone = false; /* may get set by caller */
- restrictinfo->is_clone = false; /* may get set by caller */
+ restrictinfo->has_clone = has_clone;
+ restrictinfo->is_clone = is_clone;
restrictinfo->can_join = false; /* may get set below */
restrictinfo->security_level = security_level;
+ restrictinfo->incompatible_relids = incompatible_relids;
restrictinfo->outer_relids = outer_relids;
/*
* implicit-AND lists at top level of RestrictInfo lists. Only ORs and
* simple clauses are valid RestrictInfos.
*
- * The same is_pushed_down and pseudoconstant flag
+ * The same is_pushed_down, has_clone, is_clone, and pseudoconstant flag
* values can be applied to all RestrictInfo nodes in the result. Likewise
- * for security_level and outer_relids.
+ * for security_level, incompatible_relids, and outer_relids.
*
* The given required_relids are attached to our top-level output,
* but any OR-clause constituents are allowed to default to just the
make_sub_restrictinfos(PlannerInfo *root,
Expr *clause,
bool is_pushed_down,
+ bool has_clone,
+ bool is_clone,
bool pseudoconstant,
Index security_level,
Relids required_relids,
+ Relids incompatible_relids,
Relids outer_relids)
{
if (is_orclause(clause))
make_sub_restrictinfos(root,
lfirst(temp),
is_pushed_down,
+ has_clone,
+ is_clone,
pseudoconstant,
security_level,
NULL,
+ incompatible_relids,
outer_relids));
return (Expr *) make_restrictinfo_internal(root,
clause,
make_orclause(orlist),
is_pushed_down,
+ has_clone,
+ is_clone,
pseudoconstant,
security_level,
required_relids,
+ incompatible_relids,
outer_relids);
}
else if (is_andclause(clause))
make_sub_restrictinfos(root,
lfirst(temp),
is_pushed_down,
+ has_clone,
+ is_clone,
pseudoconstant,
security_level,
required_relids,
+ incompatible_relids,
outer_relids));
return make_andclause(andlist);
}
clause,
NULL,
is_pushed_down,
+ has_clone,
+ is_clone,
pseudoconstant,
security_level,
required_relids,
+ incompatible_relids,
outer_relids);
}
{
/* joinquals shouldn't have been marked pseudoconstant */
Assert(!rinfo->pseudoconstant);
- Assert(!rinfo_is_constant_true(rinfo));
- *joinquals = lappend(*joinquals, rinfo->clause);
+ if (!rinfo_is_constant_true(rinfo))
+ *joinquals = lappend(*joinquals, rinfo->clause);
}
}
}
-/*
- * clause_is_computable_at
- * Test whether a clause is computable at a given evaluation level.
- *
- * There are two conditions for whether an expression can actually be
- * evaluated at a given join level: the evaluation context must include
- * all the relids (both base and OJ) used by the expression, and we must
- * not have already evaluated any outer joins that null Vars/PHVs of the
- * expression and are not listed in their nullingrels.
- *
- * This function checks the second condition; we assume the caller already
- * saw to the first one.
- *
- * For speed reasons, we don't individually examine each Var/PHV of the
- * expression, but just look at the overall clause_relids (the union of the
- * varnos and varnullingrels). This could give a misleading answer if the
- * Vars of a given varno don't all have the same varnullingrels; but that
- * really shouldn't happen within a single scalar expression or RestrictInfo
- * clause. Despite that, this is still annoyingly expensive :-(
- */
-bool
-clause_is_computable_at(PlannerInfo *root,
- RestrictInfo *rinfo,
- Relids eval_relids)
-{
- Relids clause_relids;
- ListCell *lc;
-
- /* Nothing to do if no outer joins have been performed yet. */
- if (!bms_overlap(eval_relids, root->outer_join_rels))
- return true;
-
- /*
- * For an ordinary qual clause, we consider the actual clause_relids as
- * explained above. However, it's possible for multiple members of a
- * group of clone quals to have the same clause_relids, so for clones use
- * the required_relids instead to ensure we select just one of them.
- */
- if (rinfo->has_clone || rinfo->is_clone)
- clause_relids = rinfo->required_relids;
- else
- clause_relids = rinfo->clause_relids;
-
- foreach(lc, root->join_info_list)
- {
- SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
-
- /* Ignore outer joins that are not yet performed. */
- if (!bms_is_member(sjinfo->ojrelid, eval_relids))
- continue;
-
- /* OK if clause lists it (we assume all Vars in it agree). */
- if (bms_is_member(sjinfo->ojrelid, clause_relids))
- continue;
-
- /* Else, trouble if clause mentions any nullable Vars. */
- if (bms_overlap(clause_relids, sjinfo->min_righthand) ||
- (sjinfo->jointype == JOIN_FULL &&
- bms_overlap(clause_relids, sjinfo->min_lefthand)))
- return false; /* doesn't work */
- }
-
- return true; /* OK */
-}
-
/*
* join_clause_is_movable_to
* Test whether a join clause is a safe candidate for parameterization
* conditions. Possibly we should rename it to reflect that meaning? But
* see also the comments for RINFO_IS_PUSHED_DOWN, below.)
*
+ * There is also an incompatible_relids field, which is a set of outer-join
+ * relids above which we cannot evaluate the clause (because they might null
+ * Vars it uses that should not be nulled yet). In principle this could be
+ * filled in any RestrictInfo as the set of OJ relids that appear above the
+ * clause and null Vars that it uses. In practice we only bother to populate
+ * it for "clone" clauses, as it's currently only needed to prevent multiple
+ * clones of the same clause from being accepted for evaluation at the same
+ * join level.
+ *
* There is also an outer_relids field, which is NULL except for outer join
* clauses; for those, it is the set of relids on the outer side of the
* clause's outer join. (These are rels that the clause cannot be applied to
/* The set of relids required to evaluate the clause: */
Relids required_relids;
+ /* Relids above which we cannot evaluate the clause (see comment above) */
+ Relids incompatible_relids;
+
/* If an outer-join clause, the outer-side relations, else NULL: */
Relids outer_relids;
/* Convenience macro for the common case of a valid-everywhere qual */
#define make_simple_restrictinfo(root, clause) \
- make_restrictinfo(root, clause, true, false, 0, NULL, NULL)
+ make_restrictinfo(root, clause, true, false, false, false, 0, \
+ NULL, NULL, NULL)
extern RestrictInfo *make_restrictinfo(PlannerInfo *root,
Expr *clause,
bool is_pushed_down,
+ bool has_clone,
+ bool is_clone,
bool pseudoconstant,
Index security_level,
Relids required_relids,
+ Relids incompatible_relids,
Relids outer_relids);
extern RestrictInfo *commute_restrictinfo(RestrictInfo *rinfo, Oid comm_op);
extern bool restriction_is_or_clause(RestrictInfo *restrictinfo);
Relids joinrelids,
List **joinquals,
List **otherquals);
-extern bool clause_is_computable_at(PlannerInfo *root,
- RestrictInfo *rinfo,
- Relids eval_relids);
extern bool join_clause_is_movable_to(RestrictInfo *rinfo, RelOptInfo *baserel);
extern bool join_clause_is_movable_into(RestrictInfo *rinfo,
Relids currentrelids,
-> Seq Scan on onek t4
(13 rows)
+explain (costs off)
+select * from int8_tbl t1 left join
+ (int8_tbl t2 left join int8_tbl t3 full join int8_tbl t4 on false on false)
+ left join int8_tbl t5 on t2.q1 = t5.q1
+on t2.q2 = 123;
+ QUERY PLAN
+--------------------------------------------------
+ Nested Loop Left Join
+ -> Seq Scan on int8_tbl t1
+ -> Materialize
+ -> Nested Loop Left Join
+ Join Filter: (t2.q1 = t5.q1)
+ -> Nested Loop Left Join
+ Join Filter: false
+ -> Seq Scan on int8_tbl t2
+ Filter: (q2 = 123)
+ -> Result
+ One-Time Filter: false
+ -> Seq Scan on int8_tbl t5
+(12 rows)
+
--
-- check a case where we formerly got confused by conflicting sort orders
-- in redundant merge join path keys
left join onek t3 on t2.unique1 = t3.unique1
left join onek t4 on t3.unique1 = t4.unique1 and t2.unique2 = t4.unique2;
+explain (costs off)
+select * from int8_tbl t1 left join
+ (int8_tbl t2 left join int8_tbl t3 full join int8_tbl t4 on false on false)
+ left join int8_tbl t5 on t2.q1 = t5.q1
+on t2.q2 = 123;
+
--
-- check a case where we formerly got confused by conflicting sort orders
-- in redundant merge join path keys
projects / postgresql.git / commitdiff