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Functions
placeholder.h File Reference
#include "nodes/pathnodes.h"
Include dependency graph for placeholder.h:
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Functions

PlaceHolderVar *  make_placeholder_expr (PlannerInfo *root, Expr *expr, Relids phrels)
 
PlaceHolderInfo *  find_placeholder_info (PlannerInfo *root, PlaceHolderVar *phv)
 
void  find_placeholders_in_jointree (PlannerInfo *root)
 
void  fix_placeholder_input_needed_levels (PlannerInfo *root)
 
void  rebuild_placeholder_attr_needed (PlannerInfo *root)
 
void  add_placeholders_to_base_rels (PlannerInfo *root)
 
void  add_placeholders_to_joinrel (PlannerInfo *root, RelOptInfo *joinrel, RelOptInfo *outer_rel, RelOptInfo *inner_rel, SpecialJoinInfo *sjinfo)
 
bool  contain_placeholder_references_to (PlannerInfo *root, Node *clause, int relid)
 
Relids  get_placeholder_nulling_relids (PlannerInfo *root, PlaceHolderInfo *phinfo)
 

Function Documentation

◆ add_placeholders_to_base_rels()

void add_placeholders_to_base_rels ( PlannerInfo *  root )

Definition at line 356 of file placeholder.c.

357{
358 ListCell *lc;
359
360 foreach(lc, root->placeholder_list)
361 {
362 PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
363 Relids eval_at = phinfo->ph_eval_at;
364 int varno;
365
366 if (bms_get_singleton_member(eval_at, &varno) &&
367 bms_nonempty_difference(phinfo->ph_needed, eval_at))
368 {
369 RelOptInfo *rel = find_base_rel(root, varno);
370
371 /*
372 * As in add_vars_to_targetlist(), a value computed at scan level
373 * has not yet been nulled by any outer join, so its phnullingrels
374 * should be empty.
375 */
376 Assert(phinfo->ph_var->phnullingrels == NULL);
377
378 /* Copying the PHV might be unnecessary here, but be safe */
379 rel->reltarget->exprs = lappend(rel->reltarget->exprs,
380 copyObject(phinfo->ph_var));
381 /* reltarget's cost and width fields will be updated later */
382 }
383 }
384}
bool bms_get_singleton_member(const Bitmapset *a, int *member)
Definition: bitmapset.c:715
bool bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:641
Assert(PointerIsAligned(start, uint64))
List * lappend(List *list, void *datum)
Definition: list.c:339
#define copyObject(obj)
Definition: nodes.h:232
#define lfirst(lc)
Definition: pg_list.h:172
tree ctl root
Definition: radixtree.h:1857
RelOptInfo * find_base_rel(PlannerInfo *root, int relid)
Definition: relnode.c:416
List * exprs
Definition: pathnodes.h:1691
Relids ph_needed
Definition: pathnodes.h:3229
Relids ph_eval_at
Definition: pathnodes.h:3223
PlaceHolderVar * ph_var
Definition: pathnodes.h:3220
Relids phnullingrels
Definition: pathnodes.h:2931
struct PathTarget * reltarget
Definition: pathnodes.h:930
Definition: pg_list.h:46

References Assert(), bms_get_singleton_member(), bms_nonempty_difference(), copyObject, PathTarget::exprs, find_base_rel(), lappend(), lfirst, PlaceHolderInfo::ph_eval_at, PlaceHolderInfo::ph_needed, PlaceHolderInfo::ph_var, PlaceHolderVar::phnullingrels, RelOptInfo::reltarget, and root.

Referenced by query_planner().

◆ add_placeholders_to_joinrel()

void add_placeholders_to_joinrel ( PlannerInfo *  root,
RelOptInfo *  joinrel,
RelOptInfo *  outer_rel,
RelOptInfo *  inner_rel,
SpecialJoinInfo *  sjinfo 
)

Definition at line 400 of file placeholder.c.

403{
404 Relids relids = joinrel->relids;
405 int64 tuple_width = joinrel->reltarget->width;
406 ListCell *lc;
407
408 foreach(lc, root->placeholder_list)
409 {
410 PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
411
412 /* Is it computable here? */
413 if (bms_is_subset(phinfo->ph_eval_at, relids))
414 {
415 /* Is it still needed above this joinrel? */
416 if (bms_nonempty_difference(phinfo->ph_needed, relids))
417 {
418 /*
419 * Yes, but only add to tlist if it wasn't computed in either
420 * input; otherwise it should be there already. Also, we
421 * charge the cost of evaluating the contained expression if
422 * the PHV can be computed here but not in either input. This
423 * is a bit bogus because we make the decision based on the
424 * first pair of possible input relations considered for the
425 * joinrel. With other pairs, it might be possible to compute
426 * the PHV in one input or the other, and then we'd be double
427 * charging the PHV's cost for some join paths. For now, live
428 * with that; but we might want to improve it later by
429 * refiguring the reltarget costs for each pair of inputs.
430 */
431 if (!bms_is_subset(phinfo->ph_eval_at, outer_rel->relids) &&
432 !bms_is_subset(phinfo->ph_eval_at, inner_rel->relids))
433 {
434 /* Copying might be unnecessary here, but be safe */
435 PlaceHolderVar *phv = copyObject(phinfo->ph_var);
436 QualCost cost;
437
438 /*
439 * It'll start out not nulled by anything. Joins above
440 * this one might add to its phnullingrels later, in much
441 * the same way as for Vars.
442 */
443 Assert(phv->phnullingrels == NULL);
444
445 joinrel->reltarget->exprs = lappend(joinrel->reltarget->exprs,
446 phv);
447 cost_qual_eval_node(&cost, (Node *) phv->phexpr, root);
448 joinrel->reltarget->cost.startup += cost.startup;
449 joinrel->reltarget->cost.per_tuple += cost.per_tuple;
450 tuple_width += phinfo->ph_width;
451 }
452 }
453
454 /*
455 * Also adjust joinrel's direct_lateral_relids to include the
456 * PHV's source rel(s). We must do this even if we're not
457 * actually going to emit the PHV, otherwise join_is_legal() will
458 * reject valid join orderings. (In principle maybe we could
459 * instead remove the joinrel's lateral_relids dependency; but
460 * that's complicated to get right, and cases where we're not
461 * going to emit the PHV are too rare to justify the work.)
462 *
463 * In principle we should only do this if the join doesn't yet
464 * include the PHV's source rel(s). But our caller
465 * build_join_rel() will clean things up by removing the join's
466 * own relids from its direct_lateral_relids, so we needn't
467 * account for that here.
468 */
469 joinrel->direct_lateral_relids =
471 phinfo->ph_lateral);
472 }
473 }
474
475 joinrel->reltarget->width = clamp_width_est(tuple_width);
476}
bool bms_is_subset(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:412
Bitmapset * bms_add_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:917
int64_t int64
Definition: c.h:535
void cost_qual_eval_node(QualCost *cost, Node *qual, PlannerInfo *root)
Definition: costsize.c:4817
int32 clamp_width_est(int64 tuple_width)
Definition: costsize.c:242
Definition: nodes.h:135
int width
Definition: pathnodes.h:1700
QualCost cost
Definition: pathnodes.h:1697
Relids ph_lateral
Definition: pathnodes.h:3226
int32 ph_width
Definition: pathnodes.h:3232
Cost per_tuple
Definition: pathnodes.h:48
Cost startup
Definition: pathnodes.h:47
Relids relids
Definition: pathnodes.h:908
Relids direct_lateral_relids
Definition: pathnodes.h:947

References Assert(), bms_add_members(), bms_is_subset(), bms_nonempty_difference(), clamp_width_est(), copyObject, PathTarget::cost, cost_qual_eval_node(), RelOptInfo::direct_lateral_relids, PathTarget::exprs, lappend(), lfirst, QualCost::per_tuple, PlaceHolderInfo::ph_eval_at, PlaceHolderInfo::ph_lateral, PlaceHolderInfo::ph_needed, PlaceHolderInfo::ph_var, PlaceHolderInfo::ph_width, PlaceHolderVar::phnullingrels, RelOptInfo::relids, RelOptInfo::reltarget, root, QualCost::startup, and PathTarget::width.

Referenced by build_join_rel().

◆ contain_placeholder_references_to()

bool contain_placeholder_references_to ( PlannerInfo *  root,
Node *  clause,
int  relid 
)

Definition at line 491 of file placeholder.c.

493{
495
496 /* We can answer quickly in the common case that there's no PHVs at all */
497 if (root->glob->lastPHId == 0)
498 return false;
499 /* Else run the recursive search */
500 context.relid = relid;
501 context.sublevels_up = 0;
502 return contain_placeholder_references_walker(clause, &context);
503}
static bool contain_placeholder_references_walker(Node *node, contain_placeholder_references_context *context)
Definition: placeholder.c:506
Definition: placeholder.c:28
int relid
Definition: placeholder.c:29
int sublevels_up
Definition: placeholder.c:30

References contain_placeholder_references_walker(), contain_placeholder_references_context::relid, root, and contain_placeholder_references_context::sublevels_up.

Referenced by make_outerjoininfo().

◆ find_placeholder_info()

PlaceHolderInfo * find_placeholder_info ( PlannerInfo *  root,
PlaceHolderVar *  phv 
)

Definition at line 83 of file placeholder.c.

84{
85 PlaceHolderInfo *phinfo;
86 Relids rels_used;
87
88 /* if this ever isn't true, we'd need to be able to look in parent lists */
89 Assert(phv->phlevelsup == 0);
90
91 /* Use placeholder_array to look up existing PlaceHolderInfo quickly */
92 if (phv->phid < root->placeholder_array_size)
93 phinfo = root->placeholder_array[phv->phid];
94 else
95 phinfo = NULL;
96 if (phinfo != NULL)
97 {
98 Assert(phinfo->phid == phv->phid);
99 return phinfo;
100 }
101
102 /* Not found, so create it */
103 if (root->placeholdersFrozen)
104 elog(ERROR, "too late to create a new PlaceHolderInfo");
105
106 phinfo = makeNode(PlaceHolderInfo);
107
108 phinfo->phid = phv->phid;
109 phinfo->ph_var = copyObject(phv);
110
111 /*
112 * By convention, phinfo->ph_var->phnullingrels is always empty, since the
113 * PlaceHolderInfo represents the initially-calculated state of the
114 * PlaceHolderVar. PlaceHolderVars appearing in the query tree might have
115 * varying values of phnullingrels, reflecting outer joins applied above
116 * the calculation level.
117 */
118 phinfo->ph_var->phnullingrels = NULL;
119
120 /*
121 * Any referenced rels that are outside the PHV's syntactic scope are
122 * LATERAL references, which should be included in ph_lateral but not in
123 * ph_eval_at. If no referenced rels are within the syntactic scope,
124 * force evaluation at the syntactic location.
125 */
126 rels_used = pull_varnos(root, (Node *) phv->phexpr);
127 phinfo->ph_lateral = bms_difference(rels_used, phv->phrels);
128 phinfo->ph_eval_at = bms_int_members(rels_used, phv->phrels);
129 /* If no contained vars, force evaluation at syntactic location */
130 if (bms_is_empty(phinfo->ph_eval_at))
131 {
132 phinfo->ph_eval_at = bms_copy(phv->phrels);
133 Assert(!bms_is_empty(phinfo->ph_eval_at));
134 }
135 phinfo->ph_needed = NULL; /* initially it's unused */
136 /* for the moment, estimate width using just the datatype info */
137 phinfo->ph_width = get_typavgwidth(exprType((Node *) phv->phexpr),
138 exprTypmod((Node *) phv->phexpr));
139
140 /*
141 * Add to both placeholder_list and placeholder_array. Note: because we
142 * store pointers to the PlaceHolderInfos in two data structures, it'd be
143 * unsafe to pass the whole placeholder_list structure through
144 * expression_tree_mutator or the like --- or at least, you'd have to
145 * rebuild the placeholder_array afterwards.
146 */
147 root->placeholder_list = lappend(root->placeholder_list, phinfo);
148
149 if (phinfo->phid >= root->placeholder_array_size)
150 {
151 /* Must allocate or enlarge placeholder_array */
152 int new_size;
153
154 new_size = root->placeholder_array_size ? root->placeholder_array_size * 2 : 8;
155 while (phinfo->phid >= new_size)
156 new_size *= 2;
157 if (root->placeholder_array)
158 root->placeholder_array =
159 repalloc0_array(root->placeholder_array, PlaceHolderInfo *, root->placeholder_array_size, new_size);
160 else
161 root->placeholder_array =
162 palloc0_array(PlaceHolderInfo *, new_size);
163 root->placeholder_array_size = new_size;
164 }
165 root->placeholder_array[phinfo->phid] = phinfo;
166
167 /*
168 * The PHV's contained expression may contain other, lower-level PHVs. We
169 * now know we need to get those into the PlaceHolderInfo list, too, so we
170 * may as well do that immediately.
171 */
172 find_placeholders_in_expr(root, (Node *) phinfo->ph_var->phexpr);
173
174 return phinfo;
175}
Bitmapset * bms_difference(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:346
Bitmapset * bms_int_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:1109
Bitmapset * bms_copy(const Bitmapset *a)
Definition: bitmapset.c:122
#define bms_is_empty(a)
Definition: bitmapset.h:118
#define ERROR
Definition: elog.h:39
#define elog(elevel,...)
Definition: elog.h:226
#define palloc0_array(type, count)
Definition: fe_memutils.h:77
int32 get_typavgwidth(Oid typid, int32 typmod)
Definition: lsyscache.c:2745
Oid exprType(const Node *expr)
Definition: nodeFuncs.c:42
int32 exprTypmod(const Node *expr)
Definition: nodeFuncs.c:301
#define makeNode(_type_)
Definition: nodes.h:161
#define repalloc0_array(pointer, type, oldcount, count)
Definition: palloc.h:109
static void find_placeholders_in_expr(PlannerInfo *root, Node *expr)
Definition: placeholder.c:257
Index phid
Definition: pathnodes.h:2934
Index phlevelsup
Definition: pathnodes.h:2937
Relids pull_varnos(PlannerInfo *root, Node *node)
Definition: var.c:114

References Assert(), bms_copy(), bms_difference(), bms_int_members(), bms_is_empty, copyObject, elog, ERROR, exprType(), exprTypmod(), find_placeholders_in_expr(), get_typavgwidth(), lappend(), makeNode, palloc0_array, PlaceHolderInfo::ph_eval_at, PlaceHolderInfo::ph_lateral, PlaceHolderInfo::ph_needed, PlaceHolderInfo::ph_var, PlaceHolderInfo::ph_width, PlaceHolderVar::phid, PlaceHolderInfo::phid, PlaceHolderVar::phlevelsup, PlaceHolderVar::phnullingrels, pull_varnos(), repalloc0_array, and root.

Referenced by add_vars_to_attr_needed(), add_vars_to_targetlist(), build_joinrel_tlist(), create_lateral_join_info(), extract_lateral_vars_from_PHVs(), find_placeholders_in_expr(), identify_current_nestloop_params(), process_subquery_nestloop_params(), replace_nestloop_params_mutator(), and set_rel_width().

◆ find_placeholders_in_jointree()

void find_placeholders_in_jointree ( PlannerInfo *  root )

Definition at line 185 of file placeholder.c.

186{
187 /* This must be done before freezing the set of PHIs */
188 Assert(!root->placeholdersFrozen);
189
190 /* We need do nothing if the query contains no PlaceHolderVars */
191 if (root->glob->lastPHId != 0)
192 {
193 /* Start recursion at top of jointree */
194 Assert(root->parse->jointree != NULL &&
195 IsA(root->parse->jointree, FromExpr));
196 find_placeholders_recurse(root, (Node *) root->parse->jointree);
197 }
198}
#define IsA(nodeptr, _type_)
Definition: nodes.h:164
static void find_placeholders_recurse(PlannerInfo *root, Node *jtnode)
Definition: placeholder.c:207

References Assert(), find_placeholders_recurse(), IsA, and root.

Referenced by query_planner().

◆ fix_placeholder_input_needed_levels()

void fix_placeholder_input_needed_levels ( PlannerInfo *  root )

Definition at line 300 of file placeholder.c.

301{
302 ListCell *lc;
303
304 foreach(lc, root->placeholder_list)
305 {
306 PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
307 List *vars = pull_var_clause((Node *) phinfo->ph_var->phexpr,
311
314 }
315}
void add_vars_to_targetlist(PlannerInfo *root, List *vars, Relids where_needed)
Definition: initsplan.c:282
void list_free(List *list)
Definition: list.c:1546
#define PVC_RECURSE_AGGREGATES
Definition: optimizer.h:184
#define PVC_RECURSE_WINDOWFUNCS
Definition: optimizer.h:186
#define PVC_INCLUDE_PLACEHOLDERS
Definition: optimizer.h:187
Definition: pg_list.h:54
Definition: regcomp.c:282
List * pull_var_clause(Node *node, int flags)
Definition: var.c:653

References add_vars_to_targetlist(), lfirst, list_free(), PlaceHolderInfo::ph_eval_at, PlaceHolderInfo::ph_var, pull_var_clause(), PVC_INCLUDE_PLACEHOLDERS, PVC_RECURSE_AGGREGATES, PVC_RECURSE_WINDOWFUNCS, and root.

Referenced by query_planner().

◆ get_placeholder_nulling_relids()

Relids get_placeholder_nulling_relids ( PlannerInfo *  root,
PlaceHolderInfo *  phinfo 
)

Definition at line 559 of file placeholder.c.

560{
561 Relids result = NULL;
562 int relid = -1;
563
564 /*
565 * Form the union of all potential nulling OJs for each baserel included
566 * in ph_eval_at.
567 */
568 while ((relid = bms_next_member(phinfo->ph_eval_at, relid)) > 0)
569 {
570 RelOptInfo *rel = root->simple_rel_array[relid];
571
572 /* ignore the RTE_GROUP RTE */
573 if (relid == root->group_rtindex)
574 continue;
575
576 if (rel == NULL) /* must be an outer join */
577 {
578 Assert(bms_is_member(relid, root->outer_join_rels));
579 continue;
580 }
581 result = bms_add_members(result, rel->nulling_relids);
582 }
583
584 /* Now remove any OJs already included in ph_eval_at, and we're done. */
585 result = bms_del_members(result, phinfo->ph_eval_at);
586 return result;
587}
int bms_next_member(const Bitmapset *a, int prevbit)
Definition: bitmapset.c:1306
Bitmapset * bms_del_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:1161
bool bms_is_member(int x, const Bitmapset *a)
Definition: bitmapset.c:510
Relids nulling_relids
Definition: pathnodes.h:970

References Assert(), bms_add_members(), bms_del_members(), bms_is_member(), bms_next_member(), RelOptInfo::nulling_relids, PlaceHolderInfo::ph_eval_at, and root.

Referenced by identify_current_nestloop_params().

◆ make_placeholder_expr()

PlaceHolderVar * make_placeholder_expr ( PlannerInfo *  root,
Expr *  expr,
Relids  phrels 
)

Definition at line 54 of file placeholder.c.

55{
57
58 phv->phexpr = expr;
59 phv->phrels = phrels;
60 phv->phnullingrels = NULL; /* caller may change this later */
61 phv->phid = ++(root->glob->lastPHId);
62 phv->phlevelsup = 0; /* caller may change this later */
63
64 return phv;
65}

References makeNode, PlaceHolderVar::phid, PlaceHolderVar::phlevelsup, PlaceHolderVar::phnullingrels, and root.

Referenced by add_nullingrels_if_needed(), mark_nullable_by_grouping(), and pullup_replace_vars_callback().

◆ rebuild_placeholder_attr_needed()

void rebuild_placeholder_attr_needed ( PlannerInfo *  root )

Definition at line 327 of file placeholder.c.

328{
329 ListCell *lc;
330
331 foreach(lc, root->placeholder_list)
332 {
333 PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
334 List *vars = pull_var_clause((Node *) phinfo->ph_var->phexpr,
338
341 }
342}
void add_vars_to_attr_needed(PlannerInfo *root, List *vars, Relids where_needed)
Definition: initsplan.c:353

References add_vars_to_attr_needed(), lfirst, list_free(), PlaceHolderInfo::ph_eval_at, PlaceHolderInfo::ph_var, pull_var_clause(), PVC_INCLUDE_PLACEHOLDERS, PVC_RECURSE_AGGREGATES, PVC_RECURSE_WINDOWFUNCS, and root.

Referenced by remove_leftjoinrel_from_query(), and remove_self_join_rel().

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