Adding upstream version 15.5.upstream/15.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 655 insertions, 0 deletions

diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c
new file mode 100644
index 0000000..e7764f4
--- /dev/null
+++ b/src/backend/optimizer/util/restrictinfo.c
@@ -0,0 +1,655 @@
+/*-------------------------------------------------------------------------
+ *
+ * restrictinfo.c
+ *	  RestrictInfo node manipulation routines.
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/optimizer/util/restrictinfo.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "optimizer/clauses.h"
+#include "optimizer/optimizer.h"
+#include "optimizer/restrictinfo.h"
+
+
+static RestrictInfo *make_restrictinfo_internal(PlannerInfo *root,
+												Expr *clause,
+												Expr *orclause,
+												bool is_pushed_down,
+												bool outerjoin_delayed,
+												bool pseudoconstant,
+												Index security_level,
+												Relids required_relids,
+												Relids outer_relids,
+												Relids nullable_relids);
+static Expr *make_sub_restrictinfos(PlannerInfo *root,
+									Expr *clause,
+									bool is_pushed_down,
+									bool outerjoin_delayed,
+									bool pseudoconstant,
+									Index security_level,
+									Relids required_relids,
+									Relids outer_relids,
+									Relids nullable_relids);
+
+
+/*
+ * make_restrictinfo
+ *
+ * Build a RestrictInfo node containing the given subexpression.
+ *
+ * The is_pushed_down, outerjoin_delayed, and pseudoconstant flags for the
+ * RestrictInfo must be supplied by the caller, as well as the correct values
+ * for security_level, outer_relids, and nullable_relids.
+ * required_relids can be NULL, in which case it defaults to the actual clause
+ * contents (i.e., clause_relids).
+ *
+ * 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.
+ */
+RestrictInfo *
+make_restrictinfo(PlannerInfo *root,
+				  Expr *clause,
+				  bool is_pushed_down,
+				  bool outerjoin_delayed,
+				  bool pseudoconstant,
+				  Index security_level,
+				  Relids required_relids,
+				  Relids outer_relids,
+				  Relids nullable_relids)
+{
+	/*
+	 * If it's an OR clause, build a modified copy with RestrictInfos inserted
+	 * above each subclause of the top-level AND/OR structure.
+	 */
+	if (is_orclause(clause))
+		return (RestrictInfo *) make_sub_restrictinfos(root,
+													   clause,
+													   is_pushed_down,
+													   outerjoin_delayed,
+													   pseudoconstant,
+													   security_level,
+													   required_relids,
+													   outer_relids,
+													   nullable_relids);
+
+	/* Shouldn't be an AND clause, else AND/OR flattening messed up */
+	Assert(!is_andclause(clause));
+
+	return make_restrictinfo_internal(root,
+									  clause,
+									  NULL,
+									  is_pushed_down,
+									  outerjoin_delayed,
+									  pseudoconstant,
+									  security_level,
+									  required_relids,
+									  outer_relids,
+									  nullable_relids);
+}
+
+/*
+ * make_restrictinfo_internal
+ *
+ * Common code for the main entry points and the recursive cases.
+ */
+static RestrictInfo *
+make_restrictinfo_internal(PlannerInfo *root,
+						   Expr *clause,
+						   Expr *orclause,
+						   bool is_pushed_down,
+						   bool outerjoin_delayed,
+						   bool pseudoconstant,
+						   Index security_level,
+						   Relids required_relids,
+						   Relids outer_relids,
+						   Relids nullable_relids)
+{
+	RestrictInfo *restrictinfo = makeNode(RestrictInfo);
+
+	restrictinfo->clause = clause;
+	restrictinfo->orclause = orclause;
+	restrictinfo->is_pushed_down = is_pushed_down;
+	restrictinfo->outerjoin_delayed = outerjoin_delayed;
+	restrictinfo->pseudoconstant = pseudoconstant;
+	restrictinfo->can_join = false; /* may get set below */
+	restrictinfo->security_level = security_level;
+	restrictinfo->outer_relids = outer_relids;
+	restrictinfo->nullable_relids = nullable_relids;
+
+	/*
+	 * If it's potentially delayable by lower-level security quals, figure out
+	 * whether it's leakproof.  We can skip testing this for level-zero quals,
+	 * since they would never get delayed on security grounds anyway.
+	 */
+	if (security_level > 0)
+		restrictinfo->leakproof = !contain_leaked_vars((Node *) clause);
+	else
+		restrictinfo->leakproof = false;	/* really, "don't know" */
+
+	/*
+	 * Mark volatility as unknown.  The contain_volatile_functions function
+	 * will determine if there are any volatile functions when called for the
+	 * first time with this RestrictInfo.
+	 */
+	restrictinfo->has_volatile = VOLATILITY_UNKNOWN;
+
+	/*
+	 * If it's a binary opclause, set up left/right relids info. In any case
+	 * set up the total clause relids info.
+	 */
+	if (is_opclause(clause) && list_length(((OpExpr *) clause)->args) == 2)
+	{
+		restrictinfo->left_relids = pull_varnos(root, get_leftop(clause));
+		restrictinfo->right_relids = pull_varnos(root, get_rightop(clause));
+
+		restrictinfo->clause_relids = bms_union(restrictinfo->left_relids,
+												restrictinfo->right_relids);
+
+		/*
+		 * Does it look like a normal join clause, i.e., a binary operator
+		 * relating expressions that come from distinct relations? If so we
+		 * might be able to use it in a join algorithm.  Note that this is a
+		 * purely syntactic test that is made regardless of context.
+		 */
+		if (!bms_is_empty(restrictinfo->left_relids) &&
+			!bms_is_empty(restrictinfo->right_relids) &&
+			!bms_overlap(restrictinfo->left_relids,
+						 restrictinfo->right_relids))
+		{
+			restrictinfo->can_join = true;
+			/* pseudoconstant should certainly not be true */
+			Assert(!restrictinfo->pseudoconstant);
+		}
+	}
+	else
+	{
+		/* Not a binary opclause, so mark left/right relid sets as empty */
+		restrictinfo->left_relids = NULL;
+		restrictinfo->right_relids = NULL;
+		/* and get the total relid set the hard way */
+		restrictinfo->clause_relids = pull_varnos(root, (Node *) clause);
+	}
+
+	/* required_relids defaults to clause_relids */
+	if (required_relids != NULL)
+		restrictinfo->required_relids = required_relids;
+	else
+		restrictinfo->required_relids = restrictinfo->clause_relids;
+
+	/*
+	 * Fill in all the cacheable fields with "not yet set" markers. None of
+	 * these will be computed until/unless needed.  Note in particular that we
+	 * don't mark a binary opclause as mergejoinable or hashjoinable here;
+	 * that happens only if it appears in the right context (top level of a
+	 * joinclause list).
+	 */
+	restrictinfo->parent_ec = NULL;
+
+	restrictinfo->eval_cost.startup = -1;
+	restrictinfo->norm_selec = -1;
+	restrictinfo->outer_selec = -1;
+
+	restrictinfo->mergeopfamilies = NIL;
+
+	restrictinfo->left_ec = NULL;
+	restrictinfo->right_ec = NULL;
+	restrictinfo->left_em = NULL;
+	restrictinfo->right_em = NULL;
+	restrictinfo->scansel_cache = NIL;
+
+	restrictinfo->outer_is_left = false;
+
+	restrictinfo->hashjoinoperator = InvalidOid;
+
+	restrictinfo->left_bucketsize = -1;
+	restrictinfo->right_bucketsize = -1;
+	restrictinfo->left_mcvfreq = -1;
+	restrictinfo->right_mcvfreq = -1;
+
+	restrictinfo->left_hasheqoperator = InvalidOid;
+	restrictinfo->right_hasheqoperator = InvalidOid;
+
+	return restrictinfo;
+}
+
+/*
+ * Recursively insert sub-RestrictInfo nodes into a boolean expression.
+ *
+ * We put RestrictInfos above simple (non-AND/OR) clauses and above
+ * sub-OR clauses, but not above sub-AND clauses, because there's no need.
+ * This may seem odd but it is closely related to the fact that we use
+ * implicit-AND lists at top level of RestrictInfo lists.  Only ORs and
+ * simple clauses are valid RestrictInfos.
+ *
+ * The same is_pushed_down, outerjoin_delayed, and pseudoconstant flag
+ * values can be applied to all RestrictInfo nodes in the result.  Likewise
+ * for security_level, outer_relids, and nullable_relids.
+ *
+ * The given required_relids are attached to our top-level output,
+ * but any OR-clause constituents are allowed to default to just the
+ * contained rels.
+ */
+static Expr *
+make_sub_restrictinfos(PlannerInfo *root,
+					   Expr *clause,
+					   bool is_pushed_down,
+					   bool outerjoin_delayed,
+					   bool pseudoconstant,
+					   Index security_level,
+					   Relids required_relids,
+					   Relids outer_relids,
+					   Relids nullable_relids)
+{
+	if (is_orclause(clause))
+	{
+		List	   *orlist = NIL;
+		ListCell   *temp;
+
+		foreach(temp, ((BoolExpr *) clause)->args)
+			orlist = lappend(orlist,
+							 make_sub_restrictinfos(root,
+													lfirst(temp),
+													is_pushed_down,
+													outerjoin_delayed,
+													pseudoconstant,
+													security_level,
+													NULL,
+													outer_relids,
+													nullable_relids));
+		return (Expr *) make_restrictinfo_internal(root,
+												   clause,
+												   make_orclause(orlist),
+												   is_pushed_down,
+												   outerjoin_delayed,
+												   pseudoconstant,
+												   security_level,
+												   required_relids,
+												   outer_relids,
+												   nullable_relids);
+	}
+	else if (is_andclause(clause))
+	{
+		List	   *andlist = NIL;
+		ListCell   *temp;
+
+		foreach(temp, ((BoolExpr *) clause)->args)
+			andlist = lappend(andlist,
+							  make_sub_restrictinfos(root,
+													 lfirst(temp),
+													 is_pushed_down,
+													 outerjoin_delayed,
+													 pseudoconstant,
+													 security_level,
+													 required_relids,
+													 outer_relids,
+													 nullable_relids));
+		return make_andclause(andlist);
+	}
+	else
+		return (Expr *) make_restrictinfo_internal(root,
+												   clause,
+												   NULL,
+												   is_pushed_down,
+												   outerjoin_delayed,
+												   pseudoconstant,
+												   security_level,
+												   required_relids,
+												   outer_relids,
+												   nullable_relids);
+}
+
+/*
+ * commute_restrictinfo
+ *
+ * Given a RestrictInfo containing a binary opclause, produce a RestrictInfo
+ * representing the commutation of that clause.  The caller must pass the
+ * OID of the commutator operator (which it's presumably looked up, else
+ * it would not know this is valid).
+ *
+ * Beware that the result shares sub-structure with the given RestrictInfo.
+ * That's okay for the intended usage with derived index quals, but might
+ * be hazardous if the source is subject to change.  Also notice that we
+ * assume without checking that the commutator op is a member of the same
+ * btree and hash opclasses as the original op.
+ */
+RestrictInfo *
+commute_restrictinfo(RestrictInfo *rinfo, Oid comm_op)
+{
+	RestrictInfo *result;
+	OpExpr	   *newclause;
+	OpExpr	   *clause = castNode(OpExpr, rinfo->clause);
+
+	Assert(list_length(clause->args) == 2);
+
+	/* flat-copy all the fields of clause ... */
+	newclause = makeNode(OpExpr);
+	memcpy(newclause, clause, sizeof(OpExpr));
+
+	/* ... and adjust those we need to change to commute it */
+	newclause->opno = comm_op;
+	newclause->opfuncid = InvalidOid;
+	newclause->args = list_make2(lsecond(clause->args),
+								 linitial(clause->args));
+
+	/* likewise, flat-copy all the fields of rinfo ... */
+	result = makeNode(RestrictInfo);
+	memcpy(result, rinfo, sizeof(RestrictInfo));
+
+	/*
+	 * ... and adjust those we need to change.  Note in particular that we can
+	 * preserve any cached selectivity or cost estimates, since those ought to
+	 * be the same for the new clause.  Likewise we can keep the source's
+	 * parent_ec.
+	 */
+	result->clause = (Expr *) newclause;
+	result->left_relids = rinfo->right_relids;
+	result->right_relids = rinfo->left_relids;
+	Assert(result->orclause == NULL);
+	result->left_ec = rinfo->right_ec;
+	result->right_ec = rinfo->left_ec;
+	result->left_em = rinfo->right_em;
+	result->right_em = rinfo->left_em;
+	result->scansel_cache = NIL;	/* not worth updating this */
+	if (rinfo->hashjoinoperator == clause->opno)
+		result->hashjoinoperator = comm_op;
+	else
+		result->hashjoinoperator = InvalidOid;
+	result->left_bucketsize = rinfo->right_bucketsize;
+	result->right_bucketsize = rinfo->left_bucketsize;
+	result->left_mcvfreq = rinfo->right_mcvfreq;
+	result->right_mcvfreq = rinfo->left_mcvfreq;
+	result->left_hasheqoperator = InvalidOid;
+	result->right_hasheqoperator = InvalidOid;
+
+	return result;
+}
+
+/*
+ * restriction_is_or_clause
+ *
+ * Returns t iff the restrictinfo node contains an 'or' clause.
+ */
+bool
+restriction_is_or_clause(RestrictInfo *restrictinfo)
+{
+	if (restrictinfo->orclause != NULL)
+		return true;
+	else
+		return false;
+}
+
+/*
+ * restriction_is_securely_promotable
+ *
+ * Returns true if it's okay to evaluate this clause "early", that is before
+ * other restriction clauses attached to the specified relation.
+ */
+bool
+restriction_is_securely_promotable(RestrictInfo *restrictinfo,
+								   RelOptInfo *rel)
+{
+	/*
+	 * It's okay if there are no baserestrictinfo clauses for the rel that
+	 * would need to go before this one, *or* if this one is leakproof.
+	 */
+	if (restrictinfo->security_level <= rel->baserestrict_min_security ||
+		restrictinfo->leakproof)
+		return true;
+	else
+		return false;
+}
+
+/*
+ * get_actual_clauses
+ *
+ * Returns a list containing the bare clauses from 'restrictinfo_list'.
+ *
+ * This is only to be used in cases where none of the RestrictInfos can
+ * be pseudoconstant clauses (for instance, it's OK on indexqual lists).
+ */
+List *
+get_actual_clauses(List *restrictinfo_list)
+{
+	List	   *result = NIL;
+	ListCell   *l;
+
+	foreach(l, restrictinfo_list)
+	{
+		RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
+
+		Assert(!rinfo->pseudoconstant);
+
+		result = lappend(result, rinfo->clause);
+	}
+	return result;
+}
+
+/*
+ * extract_actual_clauses
+ *
+ * Extract bare clauses from 'restrictinfo_list', returning either the
+ * regular ones or the pseudoconstant ones per 'pseudoconstant'.
+ */
+List *
+extract_actual_clauses(List *restrictinfo_list,
+					   bool pseudoconstant)
+{
+	List	   *result = NIL;
+	ListCell   *l;
+
+	foreach(l, restrictinfo_list)
+	{
+		RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
+
+		if (rinfo->pseudoconstant == pseudoconstant)
+			result = lappend(result, rinfo->clause);
+	}
+	return result;
+}
+
+/*
+ * 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
+ * about pushed-down-ness.
+ */
+void
+extract_actual_join_clauses(List *restrictinfo_list,
+							Relids joinrelids,
+							List **joinquals,
+							List **otherquals)
+{
+	ListCell   *l;
+
+	*joinquals = NIL;
+	*otherquals = NIL;
+
+	foreach(l, restrictinfo_list)
+	{
+		RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
+
+		if (RINFO_IS_PUSHED_DOWN(rinfo, joinrelids))
+		{
+			if (!rinfo->pseudoconstant)
+				*otherquals = lappend(*otherquals, rinfo->clause);
+		}
+		else
+		{
+			/* joinquals shouldn't have been marked pseudoconstant */
+			Assert(!rinfo->pseudoconstant);
+			*joinquals = lappend(*joinquals, rinfo->clause);
+		}
+	}
+}
+
+/*
+ * 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)
+			return true;
+	}
+	return false;
+}
+
+
+/*
+ * join_clause_is_movable_to
+ *		Test whether a join clause is a safe candidate for parameterization
+ *		of a scan on the specified base relation.
+ *
+ * A movable join clause is one that can safely be evaluated at a rel below
+ * its normal semantic level (ie, its required_relids), if the values of
+ * variables that it would need from other rels are provided.
+ *
+ * We insist that the clause actually reference the target relation; this
+ * prevents undesirable movement of degenerate join clauses, and ensures
+ * that there is a unique place that a clause can be moved down to.
+ *
+ * We cannot move an outer-join clause into the non-nullable side of its
+ * outer join, as that would change the results (rows would be suppressed
+ * rather than being null-extended).
+ *
+ * Also there must not be an outer join below the clause that would null the
+ * Vars coming from the target relation.  Otherwise the clause might give
+ * results different from what it would give at its normal semantic level.
+ *
+ * Also, the join clause must not use any relations that have LATERAL
+ * references to the target relation, since we could not put such rels on
+ * the outer side of a nestloop with the target relation.
+ */
+bool
+join_clause_is_movable_to(RestrictInfo *rinfo, RelOptInfo *baserel)
+{
+	/* Clause must physically reference target rel */
+	if (!bms_is_member(baserel->relid, rinfo->clause_relids))
+		return false;
+
+	/* Cannot move an outer-join clause into the join's outer side */
+	if (bms_is_member(baserel->relid, rinfo->outer_relids))
+		return false;
+
+	/* Target rel must not be nullable below the clause */
+	if (bms_is_member(baserel->relid, rinfo->nullable_relids))
+		return false;
+
+	/* Clause must not use any rels with LATERAL references to this rel */
+	if (bms_overlap(baserel->lateral_referencers, rinfo->clause_relids))
+		return false;
+
+	return true;
+}
+
+/*
+ * join_clause_is_movable_into
+ *		Test whether a join clause is movable and can be evaluated within
+ *		the current join context.
+ *
+ * currentrelids: the relids of the proposed evaluation location
+ * current_and_outer: the union of currentrelids and the required_outer
+ *		relids (parameterization's outer relations)
+ *
+ * The API would be a bit clearer if we passed the current relids and the
+ * outer relids separately and did bms_union internally; but since most
+ * callers need to apply this function to multiple clauses, we make the
+ * caller perform the union.
+ *
+ * Obviously, the clause must only refer to Vars available from the current
+ * relation plus the outer rels.  We also check that it does reference at
+ * least one current Var, ensuring that the clause will be pushed down to
+ * a unique place in a parameterized join tree.  And we check that we're
+ * not pushing the clause into its outer-join outer side, nor down into
+ * a lower outer join's inner side.
+ *
+ * The check about pushing a clause down into a lower outer join's inner side
+ * is only approximate; it sometimes returns "false" when actually it would
+ * be safe to use the clause here because we're still above the outer join
+ * in question.  This is okay as long as the answers at different join levels
+ * are consistent: it just means we might sometimes fail to push a clause as
+ * far down as it could safely be pushed.  It's unclear whether it would be
+ * worthwhile to do this more precisely.  (But if it's ever fixed to be
+ * exactly accurate, there's an Assert in get_joinrel_parampathinfo() that
+ * should be re-enabled.)
+ *
+ * There's no check here equivalent to join_clause_is_movable_to's test on
+ * lateral_referencers.  We assume the caller wouldn't be inquiring unless
+ * it'd verified that the proposed outer rels don't have lateral references
+ * to the current rel(s).  (If we are considering join paths with the outer
+ * rels on the outside and the current rels on the inside, then this should
+ * have been checked at the outset of such consideration; see join_is_legal
+ * and the path parameterization checks in joinpath.c.)  On the other hand,
+ * in join_clause_is_movable_to we are asking whether the clause could be
+ * moved for some valid set of outer rels, so we don't have the benefit of
+ * relying on prior checks for lateral-reference validity.
+ *
+ * Note: if this returns true, it means that the clause could be moved to
+ * this join relation, but that doesn't mean that this is the lowest join
+ * it could be moved to.  Caller may need to make additional calls to verify
+ * that this doesn't succeed on either of the inputs of a proposed join.
+ *
+ * Note: get_joinrel_parampathinfo depends on the fact that if
+ * current_and_outer is NULL, this function will always return false
+ * (since one or the other of the first two tests must fail).
+ */
+bool
+join_clause_is_movable_into(RestrictInfo *rinfo,
+							Relids currentrelids,
+							Relids current_and_outer)
+{
+	/* Clause must be evaluable given available context */
+	if (!bms_is_subset(rinfo->clause_relids, current_and_outer))
+		return false;
+
+	/* Clause must physically reference at least one target rel */
+	if (!bms_overlap(currentrelids, rinfo->clause_relids))
+		return false;
+
+	/* Cannot move an outer-join clause into the join's outer side */
+	if (bms_overlap(currentrelids, rinfo->outer_relids))
+		return false;
+
+	/*
+	 * Target rel(s) must not be nullable below the clause.  This is
+	 * approximate, in the safe direction, because the current join might be
+	 * above the join where the nulling would happen, in which case the clause
+	 * would work correctly here.  But we don't have enough info to be sure.
+	 */
+	if (bms_overlap(currentrelids, rinfo->nullable_relids))
+		return false;
+
+	return true;
+}