Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * var.c
4 : * Var node manipulation routines
5 : *
6 : * Note: for most purposes, PlaceHolderVar is considered a Var too,
7 : * even if its contained expression is variable-free. Also, CurrentOfExpr
8 : * is treated as a Var for purposes of determining whether an expression
9 : * contains variables.
10 : *
11 : *
12 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
13 : * Portions Copyright (c) 1994, Regents of the University of California
14 : *
15 : *
16 : * IDENTIFICATION
17 : * src/backend/optimizer/util/var.c
18 : *
19 : *-------------------------------------------------------------------------
20 : */
21 : #include "postgres.h"
22 :
23 : #include "access/sysattr.h"
24 : #include "nodes/nodeFuncs.h"
25 : #include "optimizer/optimizer.h"
26 : #include "optimizer/placeholder.h"
27 : #include "optimizer/prep.h"
28 : #include "parser/parsetree.h"
29 : #include "rewrite/rewriteManip.h"
30 :
31 :
32 : typedef struct
33 : {
34 : Relids varnos;
35 : PlannerInfo *root;
36 : int sublevels_up;
37 : } pull_varnos_context;
38 :
39 : typedef struct
40 : {
41 : Bitmapset *varattnos;
42 : Index varno;
43 : } pull_varattnos_context;
44 :
45 : typedef struct
46 : {
47 : List *vars;
48 : int sublevels_up;
49 : } pull_vars_context;
50 :
51 : typedef struct
52 : {
53 : int var_location;
54 : int sublevels_up;
55 : } locate_var_of_level_context;
56 :
57 : typedef struct
58 : {
59 : List *varlist;
60 : int flags;
61 : } pull_var_clause_context;
62 :
63 : typedef struct
64 : {
65 : PlannerInfo *root; /* could be NULL! */
66 : Query *query; /* outer Query */
67 : int sublevels_up;
68 : bool possible_sublink; /* could aliases include a SubLink? */
69 : bool inserted_sublink; /* have we inserted a SubLink? */
70 : } flatten_join_alias_vars_context;
71 :
72 : static bool pull_varnos_walker(Node *node,
73 : pull_varnos_context *context);
74 : static bool pull_varattnos_walker(Node *node, pull_varattnos_context *context);
75 : static bool pull_vars_walker(Node *node, pull_vars_context *context);
76 : static bool contain_var_clause_walker(Node *node, void *context);
77 : static bool contain_vars_of_level_walker(Node *node, int *sublevels_up);
78 : static bool locate_var_of_level_walker(Node *node,
79 : locate_var_of_level_context *context);
80 : static bool pull_var_clause_walker(Node *node,
81 : pull_var_clause_context *context);
82 : static Node *flatten_join_alias_vars_mutator(Node *node,
83 : flatten_join_alias_vars_context *context);
84 : static Node *add_nullingrels_if_needed(PlannerInfo *root, Node *newnode,
85 : Var *oldvar);
86 : static bool is_standard_join_alias_expression(Node *newnode, Var *oldvar);
87 : static void adjust_standard_join_alias_expression(Node *newnode, Var *oldvar);
88 : static Relids alias_relid_set(Query *query, Relids relids);
89 :
90 :
91 : /*
92 : * pull_varnos
93 : * Create a set of all the distinct varnos present in a parsetree.
94 : * Only varnos that reference level-zero rtable entries are considered.
95 : *
96 : * The result includes outer-join relids mentioned in Var.varnullingrels and
97 : * PlaceHolderVar.phnullingrels fields in the parsetree.
98 : *
99 : * "root" can be passed as NULL if it is not necessary to process
100 : * PlaceHolderVars.
101 : *
102 : * NOTE: this is used on not-yet-planned expressions. It may therefore find
103 : * bare SubLinks, and if so it needs to recurse into them to look for uplevel
104 : * references to the desired rtable level! But when we find a completed
105 : * SubPlan, we only need to look at the parameters passed to the subplan.
106 : */
107 : Relids
108 2571570 : pull_varnos(PlannerInfo *root, Node *node)
109 : {
110 : pull_varnos_context context;
111 :
112 2571570 : context.varnos = NULL;
113 2571570 : context.root = root;
114 2571570 : context.sublevels_up = 0;
115 :
116 : /*
117 : * Must be prepared to start with a Query or a bare expression tree; if
118 : * it's a Query, we don't want to increment sublevels_up.
119 : */
120 2571570 : query_or_expression_tree_walker(node,
121 : pull_varnos_walker,
122 : (void *) &context,
123 : 0);
124 :
125 2571570 : return context.varnos;
126 : }
127 :
128 : /*
129 : * pull_varnos_of_level
130 : * Create a set of all the distinct varnos present in a parsetree.
131 : * Only Vars of the specified level are considered.
132 : */
133 : Relids
134 3162 : pull_varnos_of_level(PlannerInfo *root, Node *node, int levelsup)
135 : {
136 : pull_varnos_context context;
137 :
138 3162 : context.varnos = NULL;
139 3162 : context.root = root;
140 3162 : context.sublevels_up = levelsup;
141 :
142 : /*
143 : * Must be prepared to start with a Query or a bare expression tree; if
144 : * it's a Query, we don't want to increment sublevels_up.
145 : */
146 3162 : query_or_expression_tree_walker(node,
147 : pull_varnos_walker,
148 : (void *) &context,
149 : 0);
150 :
151 3162 : return context.varnos;
152 : }
153 :
154 : static bool
155 4331960 : pull_varnos_walker(Node *node, pull_varnos_context *context)
156 : {
157 4331960 : if (node == NULL)
158 91670 : return false;
159 4240290 : if (IsA(node, Var))
160 : {
161 2084246 : Var *var = (Var *) node;
162 :
163 2084246 : if (var->varlevelsup == context->sublevels_up)
164 : {
165 2078704 : context->varnos = bms_add_member(context->varnos, var->varno);
166 2078704 : context->varnos = bms_add_members(context->varnos,
167 2078704 : var->varnullingrels);
168 : }
169 2084246 : return false;
170 : }
171 2156044 : if (IsA(node, CurrentOfExpr))
172 : {
173 800 : CurrentOfExpr *cexpr = (CurrentOfExpr *) node;
174 :
175 800 : if (context->sublevels_up == 0)
176 800 : context->varnos = bms_add_member(context->varnos, cexpr->cvarno);
177 800 : return false;
178 : }
179 2155244 : if (IsA(node, PlaceHolderVar))
180 : {
181 4558 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
182 :
183 : /*
184 : * If a PlaceHolderVar is not of the target query level, ignore it,
185 : * instead recursing into its expression to see if it contains any
186 : * vars that are of the target level. We'll also do that when the
187 : * caller doesn't pass a "root" pointer. (We probably shouldn't see
188 : * PlaceHolderVars at all in such cases, but if we do, this is a
189 : * reasonable behavior.)
190 : */
191 4558 : if (phv->phlevelsup == context->sublevels_up &&
192 4558 : context->root != NULL)
193 : {
194 : /*
195 : * Ideally, the PHV's contribution to context->varnos is its
196 : * ph_eval_at set. However, this code can be invoked before
197 : * that's been computed. If we cannot find a PlaceHolderInfo,
198 : * fall back to the conservative assumption that the PHV will be
199 : * evaluated at its syntactic level (phv->phrels).
200 : *
201 : * Another problem is that a PlaceHolderVar can appear in quals or
202 : * tlists that have been translated for use in a child appendrel.
203 : * Typically such a PHV is a parameter expression sourced by some
204 : * other relation, so that the translation from parent appendrel
205 : * to child doesn't change its phrels, and we should still take
206 : * ph_eval_at at face value. But in corner cases, the PHV's
207 : * original phrels can include the parent appendrel itself, in
208 : * which case the translated PHV will have the child appendrel in
209 : * phrels, and we must translate ph_eval_at to match.
210 : */
211 4558 : PlaceHolderInfo *phinfo = NULL;
212 :
213 4558 : if (phv->phlevelsup == 0)
214 : {
215 4510 : if (phv->phid < context->root->placeholder_array_size)
216 4244 : phinfo = context->root->placeholder_array[phv->phid];
217 : }
218 4558 : if (phinfo == NULL)
219 : {
220 : /* No PlaceHolderInfo yet, use phrels */
221 326 : context->varnos = bms_add_members(context->varnos,
222 326 : phv->phrels);
223 : }
224 4232 : else if (bms_equal(phv->phrels, phinfo->ph_var->phrels))
225 : {
226 : /* Normal case: use ph_eval_at */
227 3338 : context->varnos = bms_add_members(context->varnos,
228 3338 : phinfo->ph_eval_at);
229 : }
230 : else
231 : {
232 : /* Translated PlaceHolderVar: translate ph_eval_at to match */
233 : Relids newevalat,
234 : delta;
235 :
236 : /* remove what was removed from phv->phrels ... */
237 894 : delta = bms_difference(phinfo->ph_var->phrels, phv->phrels);
238 894 : newevalat = bms_difference(phinfo->ph_eval_at, delta);
239 : /* ... then if that was in fact part of ph_eval_at ... */
240 894 : if (!bms_equal(newevalat, phinfo->ph_eval_at))
241 : {
242 : /* ... add what was added */
243 600 : delta = bms_difference(phv->phrels, phinfo->ph_var->phrels);
244 600 : newevalat = bms_join(newevalat, delta);
245 : }
246 894 : context->varnos = bms_join(context->varnos,
247 : newevalat);
248 : }
249 :
250 : /*
251 : * In all three cases, include phnullingrels in the result. We
252 : * don't worry about possibly needing to translate it, because
253 : * appendrels only translate varnos of baserels, not outer joins.
254 : */
255 9116 : context->varnos = bms_add_members(context->varnos,
256 4558 : phv->phnullingrels);
257 4558 : return false; /* don't recurse into expression */
258 : }
259 : }
260 2150686 : else if (IsA(node, Query))
261 : {
262 : /* Recurse into RTE subquery or not-yet-planned sublink subquery */
263 : bool result;
264 :
265 1526 : context->sublevels_up++;
266 1526 : result = query_tree_walker((Query *) node, pull_varnos_walker,
267 : (void *) context, 0);
268 1526 : context->sublevels_up--;
269 1526 : return result;
270 : }
271 2149160 : return expression_tree_walker(node, pull_varnos_walker,
272 : (void *) context);
273 : }
274 :
275 :
276 : /*
277 : * pull_varattnos
278 : * Find all the distinct attribute numbers present in an expression tree,
279 : * and add them to the initial contents of *varattnos.
280 : * Only Vars of the given varno and rtable level zero are considered.
281 : *
282 : * Attribute numbers are offset by FirstLowInvalidHeapAttributeNumber so that
283 : * we can include system attributes (e.g., OID) in the bitmap representation.
284 : *
285 : * Currently, this does not support unplanned subqueries; that is not needed
286 : * for current uses. It will handle already-planned SubPlan nodes, though,
287 : * looking into only the "testexpr" and the "args" list. (The subplan cannot
288 : * contain any other references to Vars of the current level.)
289 : */
290 : void
291 1442144 : pull_varattnos(Node *node, Index varno, Bitmapset **varattnos)
292 : {
293 : pull_varattnos_context context;
294 :
295 1442144 : context.varattnos = *varattnos;
296 1442144 : context.varno = varno;
297 :
298 1442144 : (void) pull_varattnos_walker(node, &context);
299 :
300 1442144 : *varattnos = context.varattnos;
301 1442144 : }
302 :
303 : static bool
304 4743654 : pull_varattnos_walker(Node *node, pull_varattnos_context *context)
305 : {
306 4743654 : if (node == NULL)
307 67318 : return false;
308 4676336 : if (IsA(node, Var))
309 : {
310 2678692 : Var *var = (Var *) node;
311 :
312 2678692 : if (var->varno == context->varno && var->varlevelsup == 0)
313 2678266 : context->varattnos =
314 2678266 : bms_add_member(context->varattnos,
315 2678266 : var->varattno - FirstLowInvalidHeapAttributeNumber);
316 2678692 : return false;
317 : }
318 :
319 : /* Should not find an unplanned subquery */
320 : Assert(!IsA(node, Query));
321 :
322 1997644 : return expression_tree_walker(node, pull_varattnos_walker,
323 : (void *) context);
324 : }
325 :
326 :
327 : /*
328 : * pull_vars_of_level
329 : * Create a list of all Vars (and PlaceHolderVars) referencing the
330 : * specified query level in the given parsetree.
331 : *
332 : * Caution: the Vars are not copied, only linked into the list.
333 : */
334 : List *
335 9008 : pull_vars_of_level(Node *node, int levelsup)
336 : {
337 : pull_vars_context context;
338 :
339 9008 : context.vars = NIL;
340 9008 : context.sublevels_up = levelsup;
341 :
342 : /*
343 : * Must be prepared to start with a Query or a bare expression tree; if
344 : * it's a Query, we don't want to increment sublevels_up.
345 : */
346 9008 : query_or_expression_tree_walker(node,
347 : pull_vars_walker,
348 : (void *) &context,
349 : 0);
350 :
351 9008 : return context.vars;
352 : }
353 :
354 : static bool
355 103848 : pull_vars_walker(Node *node, pull_vars_context *context)
356 : {
357 103848 : if (node == NULL)
358 12484 : return false;
359 91364 : if (IsA(node, Var))
360 : {
361 12090 : Var *var = (Var *) node;
362 :
363 12090 : if (var->varlevelsup == context->sublevels_up)
364 9632 : context->vars = lappend(context->vars, var);
365 12090 : return false;
366 : }
367 79274 : if (IsA(node, PlaceHolderVar))
368 : {
369 84 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
370 :
371 84 : if (phv->phlevelsup == context->sublevels_up)
372 84 : context->vars = lappend(context->vars, phv);
373 : /* we don't want to look into the contained expression */
374 84 : return false;
375 : }
376 79190 : if (IsA(node, Query))
377 : {
378 : /* Recurse into RTE subquery or not-yet-planned sublink subquery */
379 : bool result;
380 :
381 300 : context->sublevels_up++;
382 300 : result = query_tree_walker((Query *) node, pull_vars_walker,
383 : (void *) context, 0);
384 300 : context->sublevels_up--;
385 300 : return result;
386 : }
387 78890 : return expression_tree_walker(node, pull_vars_walker,
388 : (void *) context);
389 : }
390 :
391 :
392 : /*
393 : * contain_var_clause
394 : * Recursively scan a clause to discover whether it contains any Var nodes
395 : * (of the current query level).
396 : *
397 : * Returns true if any varnode found.
398 : *
399 : * Does not examine subqueries, therefore must only be used after reduction
400 : * of sublinks to subplans!
401 : */
402 : bool
403 17414 : contain_var_clause(Node *node)
404 : {
405 17414 : return contain_var_clause_walker(node, NULL);
406 : }
407 :
408 : static bool
409 23134 : contain_var_clause_walker(Node *node, void *context)
410 : {
411 23134 : if (node == NULL)
412 106 : return false;
413 23028 : if (IsA(node, Var))
414 : {
415 2198 : if (((Var *) node)->varlevelsup == 0)
416 2198 : return true; /* abort the tree traversal and return true */
417 0 : return false;
418 : }
419 20830 : if (IsA(node, CurrentOfExpr))
420 0 : return true;
421 20830 : if (IsA(node, PlaceHolderVar))
422 : {
423 12 : if (((PlaceHolderVar *) node)->phlevelsup == 0)
424 12 : return true; /* abort the tree traversal and return true */
425 : /* else fall through to check the contained expr */
426 : }
427 20818 : return expression_tree_walker(node, contain_var_clause_walker, context);
428 : }
429 :
430 :
431 : /*
432 : * contain_vars_of_level
433 : * Recursively scan a clause to discover whether it contains any Var nodes
434 : * of the specified query level.
435 : *
436 : * Returns true if any such Var found.
437 : *
438 : * Will recurse into sublinks. Also, may be invoked directly on a Query.
439 : */
440 : bool
441 137946 : contain_vars_of_level(Node *node, int levelsup)
442 : {
443 137946 : int sublevels_up = levelsup;
444 :
445 137946 : return query_or_expression_tree_walker(node,
446 : contain_vars_of_level_walker,
447 : (void *) &sublevels_up,
448 : 0);
449 : }
450 :
451 : static bool
452 427172 : contain_vars_of_level_walker(Node *node, int *sublevels_up)
453 : {
454 427172 : if (node == NULL)
455 80852 : return false;
456 346320 : if (IsA(node, Var))
457 : {
458 60072 : if (((Var *) node)->varlevelsup == *sublevels_up)
459 39494 : return true; /* abort tree traversal and return true */
460 20578 : return false;
461 : }
462 286248 : if (IsA(node, CurrentOfExpr))
463 : {
464 184 : if (*sublevels_up == 0)
465 184 : return true;
466 0 : return false;
467 : }
468 286064 : if (IsA(node, PlaceHolderVar))
469 : {
470 72 : if (((PlaceHolderVar *) node)->phlevelsup == *sublevels_up)
471 72 : return true; /* abort the tree traversal and return true */
472 : /* else fall through to check the contained expr */
473 : }
474 285992 : if (IsA(node, Query))
475 : {
476 : /* Recurse into subselects */
477 : bool result;
478 :
479 548 : (*sublevels_up)++;
480 548 : result = query_tree_walker((Query *) node,
481 : contain_vars_of_level_walker,
482 : (void *) sublevels_up,
483 : 0);
484 548 : (*sublevels_up)--;
485 548 : return result;
486 : }
487 285444 : return expression_tree_walker(node,
488 : contain_vars_of_level_walker,
489 : (void *) sublevels_up);
490 : }
491 :
492 :
493 : /*
494 : * locate_var_of_level
495 : * Find the parse location of any Var of the specified query level.
496 : *
497 : * Returns -1 if no such Var is in the querytree, or if they all have
498 : * unknown parse location. (The former case is probably caller error,
499 : * but we don't bother to distinguish it from the latter case.)
500 : *
501 : * Will recurse into sublinks. Also, may be invoked directly on a Query.
502 : *
503 : * Note: it might seem appropriate to merge this functionality into
504 : * contain_vars_of_level, but that would complicate that function's API.
505 : * Currently, the only uses of this function are for error reporting,
506 : * and so shaving cycles probably isn't very important.
507 : */
508 : int
509 12 : locate_var_of_level(Node *node, int levelsup)
510 : {
511 : locate_var_of_level_context context;
512 :
513 12 : context.var_location = -1; /* in case we find nothing */
514 12 : context.sublevels_up = levelsup;
515 :
516 12 : (void) query_or_expression_tree_walker(node,
517 : locate_var_of_level_walker,
518 : (void *) &context,
519 : 0);
520 :
521 12 : return context.var_location;
522 : }
523 :
524 : static bool
525 30 : locate_var_of_level_walker(Node *node,
526 : locate_var_of_level_context *context)
527 : {
528 30 : if (node == NULL)
529 0 : return false;
530 30 : if (IsA(node, Var))
531 : {
532 12 : Var *var = (Var *) node;
533 :
534 12 : if (var->varlevelsup == context->sublevels_up &&
535 12 : var->location >= 0)
536 : {
537 12 : context->var_location = var->location;
538 12 : return true; /* abort tree traversal and return true */
539 : }
540 0 : return false;
541 : }
542 18 : if (IsA(node, CurrentOfExpr))
543 : {
544 : /* since CurrentOfExpr doesn't carry location, nothing we can do */
545 0 : return false;
546 : }
547 : /* No extra code needed for PlaceHolderVar; just look in contained expr */
548 18 : if (IsA(node, Query))
549 : {
550 : /* Recurse into subselects */
551 : bool result;
552 :
553 0 : context->sublevels_up++;
554 0 : result = query_tree_walker((Query *) node,
555 : locate_var_of_level_walker,
556 : (void *) context,
557 : 0);
558 0 : context->sublevels_up--;
559 0 : return result;
560 : }
561 18 : return expression_tree_walker(node,
562 : locate_var_of_level_walker,
563 : (void *) context);
564 : }
565 :
566 :
567 : /*
568 : * pull_var_clause
569 : * Recursively pulls all Var nodes from an expression clause.
570 : *
571 : * Aggrefs are handled according to these bits in 'flags':
572 : * PVC_INCLUDE_AGGREGATES include Aggrefs in output list
573 : * PVC_RECURSE_AGGREGATES recurse into Aggref arguments
574 : * neither flag throw error if Aggref found
575 : * Vars within an Aggref's expression are included in the result only
576 : * when PVC_RECURSE_AGGREGATES is specified.
577 : *
578 : * WindowFuncs are handled according to these bits in 'flags':
579 : * PVC_INCLUDE_WINDOWFUNCS include WindowFuncs in output list
580 : * PVC_RECURSE_WINDOWFUNCS recurse into WindowFunc arguments
581 : * neither flag throw error if WindowFunc found
582 : * Vars within a WindowFunc's expression are included in the result only
583 : * when PVC_RECURSE_WINDOWFUNCS is specified.
584 : *
585 : * PlaceHolderVars are handled according to these bits in 'flags':
586 : * PVC_INCLUDE_PLACEHOLDERS include PlaceHolderVars in output list
587 : * PVC_RECURSE_PLACEHOLDERS recurse into PlaceHolderVar arguments
588 : * neither flag throw error if PlaceHolderVar found
589 : * Vars within a PHV's expression are included in the result only
590 : * when PVC_RECURSE_PLACEHOLDERS is specified.
591 : *
592 : * GroupingFuncs are treated exactly like Aggrefs, and so do not need
593 : * their own flag bits.
594 : *
595 : * CurrentOfExpr nodes are ignored in all cases.
596 : *
597 : * Upper-level vars (with varlevelsup > 0) should not be seen here,
598 : * likewise for upper-level Aggrefs and PlaceHolderVars.
599 : *
600 : * Returns list of nodes found. Note the nodes themselves are not
601 : * copied, only referenced.
602 : *
603 : * Does not examine subqueries, therefore must only be used after reduction
604 : * of sublinks to subplans!
605 : */
606 : List *
607 585614 : pull_var_clause(Node *node, int flags)
608 : {
609 : pull_var_clause_context context;
610 :
611 : /* Assert that caller has not specified inconsistent flags */
612 : Assert((flags & (PVC_INCLUDE_AGGREGATES | PVC_RECURSE_AGGREGATES))
613 : != (PVC_INCLUDE_AGGREGATES | PVC_RECURSE_AGGREGATES));
614 : Assert((flags & (PVC_INCLUDE_WINDOWFUNCS | PVC_RECURSE_WINDOWFUNCS))
615 : != (PVC_INCLUDE_WINDOWFUNCS | PVC_RECURSE_WINDOWFUNCS));
616 : Assert((flags & (PVC_INCLUDE_PLACEHOLDERS | PVC_RECURSE_PLACEHOLDERS))
617 : != (PVC_INCLUDE_PLACEHOLDERS | PVC_RECURSE_PLACEHOLDERS));
618 :
619 585614 : context.varlist = NIL;
620 585614 : context.flags = flags;
621 :
622 585614 : pull_var_clause_walker(node, &context);
623 585614 : return context.varlist;
624 : }
625 :
626 : static bool
627 3575076 : pull_var_clause_walker(Node *node, pull_var_clause_context *context)
628 : {
629 3575076 : if (node == NULL)
630 146600 : return false;
631 3428476 : if (IsA(node, Var))
632 : {
633 1315720 : if (((Var *) node)->varlevelsup != 0)
634 0 : elog(ERROR, "Upper-level Var found where not expected");
635 1315720 : context->varlist = lappend(context->varlist, node);
636 1315720 : return false;
637 : }
638 2112756 : else if (IsA(node, Aggref))
639 : {
640 80812 : if (((Aggref *) node)->agglevelsup != 0)
641 0 : elog(ERROR, "Upper-level Aggref found where not expected");
642 80812 : if (context->flags & PVC_INCLUDE_AGGREGATES)
643 : {
644 4680 : context->varlist = lappend(context->varlist, node);
645 : /* we do NOT descend into the contained expression */
646 4680 : return false;
647 : }
648 76132 : else if (context->flags & PVC_RECURSE_AGGREGATES)
649 : {
650 : /* fall through to recurse into the aggregate's arguments */
651 : }
652 : else
653 0 : elog(ERROR, "Aggref found where not expected");
654 : }
655 2031944 : else if (IsA(node, GroupingFunc))
656 : {
657 550 : if (((GroupingFunc *) node)->agglevelsup != 0)
658 0 : elog(ERROR, "Upper-level GROUPING found where not expected");
659 550 : if (context->flags & PVC_INCLUDE_AGGREGATES)
660 : {
661 4 : context->varlist = lappend(context->varlist, node);
662 : /* we do NOT descend into the contained expression */
663 4 : return false;
664 : }
665 546 : else if (context->flags & PVC_RECURSE_AGGREGATES)
666 : {
667 : /* fall through to recurse into the GroupingFunc's arguments */
668 : }
669 : else
670 0 : elog(ERROR, "GROUPING found where not expected");
671 : }
672 2031394 : else if (IsA(node, WindowFunc))
673 : {
674 : /* WindowFuncs have no levelsup field to check ... */
675 6400 : if (context->flags & PVC_INCLUDE_WINDOWFUNCS)
676 : {
677 12 : context->varlist = lappend(context->varlist, node);
678 : /* we do NOT descend into the contained expressions */
679 12 : return false;
680 : }
681 6388 : else if (context->flags & PVC_RECURSE_WINDOWFUNCS)
682 : {
683 : /* fall through to recurse into the windowfunc's arguments */
684 : }
685 : else
686 0 : elog(ERROR, "WindowFunc found where not expected");
687 : }
688 2024994 : else if (IsA(node, PlaceHolderVar))
689 : {
690 2618 : if (((PlaceHolderVar *) node)->phlevelsup != 0)
691 0 : elog(ERROR, "Upper-level PlaceHolderVar found where not expected");
692 2618 : if (context->flags & PVC_INCLUDE_PLACEHOLDERS)
693 : {
694 2226 : context->varlist = lappend(context->varlist, node);
695 : /* we do NOT descend into the contained expression */
696 2226 : return false;
697 : }
698 392 : else if (context->flags & PVC_RECURSE_PLACEHOLDERS)
699 : {
700 : /* fall through to recurse into the placeholder's expression */
701 : }
702 : else
703 0 : elog(ERROR, "PlaceHolderVar found where not expected");
704 : }
705 2105834 : return expression_tree_walker(node, pull_var_clause_walker,
706 : (void *) context);
707 : }
708 :
709 :
710 : /*
711 : * flatten_join_alias_vars
712 : * Replace Vars that reference JOIN outputs with references to the original
713 : * relation variables instead. This allows quals involving such vars to be
714 : * pushed down. Whole-row Vars that reference JOIN relations are expanded
715 : * into RowExpr constructs that name the individual output Vars. This
716 : * is necessary since we will not scan the JOIN as a base relation, which
717 : * is the only way that the executor can directly handle whole-row Vars.
718 : *
719 : * This also adjusts relid sets found in some expression node types to
720 : * substitute the contained base+OJ rels for any join relid.
721 : *
722 : * If a JOIN contains sub-selects that have been flattened, its join alias
723 : * entries might now be arbitrary expressions, not just Vars. This affects
724 : * this function in two important ways. First, we might find ourselves
725 : * inserting SubLink expressions into subqueries, and we must make sure that
726 : * their Query.hasSubLinks fields get set to true if so. If there are any
727 : * SubLinks in the join alias lists, the outer Query should already have
728 : * hasSubLinks = true, so this is only relevant to un-flattened subqueries.
729 : * Second, we have to preserve any varnullingrels info attached to the
730 : * alias Vars we're replacing. If the replacement expression is a Var or
731 : * PlaceHolderVar or constructed from those, we can just add the
732 : * varnullingrels bits to the existing nullingrels field(s); otherwise
733 : * we have to add a PlaceHolderVar wrapper.
734 : *
735 : * NOTE: this is also used by the parser, to expand join alias Vars before
736 : * checking GROUP BY validity. For that use-case, root will be NULL, which
737 : * is why we have to pass the Query separately. We need the root itself only
738 : * for making PlaceHolderVars. We can avoid making PlaceHolderVars in the
739 : * parser's usage because it won't be dealing with arbitrary expressions:
740 : * so long as adjust_standard_join_alias_expression can handle everything
741 : * the parser would make as a join alias expression, we're OK.
742 : */
743 : Node *
744 185256 : flatten_join_alias_vars(PlannerInfo *root, Query *query, Node *node)
745 : {
746 : flatten_join_alias_vars_context context;
747 :
748 : /*
749 : * We do not expect this to be applied to the whole Query, only to
750 : * expressions or LATERAL subqueries. Hence, if the top node is a Query,
751 : * it's okay to immediately increment sublevels_up.
752 : */
753 : Assert(node != (Node *) query);
754 :
755 185256 : context.root = root;
756 185256 : context.query = query;
757 185256 : context.sublevels_up = 0;
758 : /* flag whether join aliases could possibly contain SubLinks */
759 185256 : context.possible_sublink = query->hasSubLinks;
760 : /* if hasSubLinks is already true, no need to work hard */
761 185256 : context.inserted_sublink = query->hasSubLinks;
762 :
763 185256 : return flatten_join_alias_vars_mutator(node, &context);
764 : }
765 :
766 : static Node *
767 2447450 : flatten_join_alias_vars_mutator(Node *node,
768 : flatten_join_alias_vars_context *context)
769 : {
770 2447450 : if (node == NULL)
771 217180 : return NULL;
772 2230270 : if (IsA(node, Var))
773 : {
774 676860 : Var *var = (Var *) node;
775 : RangeTblEntry *rte;
776 : Node *newvar;
777 :
778 : /* No change unless Var belongs to a JOIN of the target level */
779 676860 : if (var->varlevelsup != context->sublevels_up)
780 41268 : return node; /* no need to copy, really */
781 635592 : rte = rt_fetch(var->varno, context->query->rtable);
782 635592 : if (rte->rtekind != RTE_JOIN)
783 635058 : return node;
784 534 : if (var->varattno == InvalidAttrNumber)
785 : {
786 : /* Must expand whole-row reference */
787 : RowExpr *rowexpr;
788 6 : List *fields = NIL;
789 6 : List *colnames = NIL;
790 : ListCell *lv;
791 : ListCell *ln;
792 :
793 : Assert(list_length(rte->joinaliasvars) == list_length(rte->eref->colnames));
794 48 : forboth(lv, rte->joinaliasvars, ln, rte->eref->colnames)
795 : {
796 42 : newvar = (Node *) lfirst(lv);
797 : /* Ignore dropped columns */
798 42 : if (newvar == NULL)
799 0 : continue;
800 42 : newvar = copyObject(newvar);
801 :
802 : /*
803 : * If we are expanding an alias carried down from an upper
804 : * query, must adjust its varlevelsup fields.
805 : */
806 42 : if (context->sublevels_up != 0)
807 0 : IncrementVarSublevelsUp(newvar, context->sublevels_up, 0);
808 : /* Preserve original Var's location, if possible */
809 42 : if (IsA(newvar, Var))
810 42 : ((Var *) newvar)->location = var->location;
811 : /* Recurse in case join input is itself a join */
812 : /* (also takes care of setting inserted_sublink if needed) */
813 42 : newvar = flatten_join_alias_vars_mutator(newvar, context);
814 42 : fields = lappend(fields, newvar);
815 : /* We need the names of non-dropped columns, too */
816 42 : colnames = lappend(colnames, copyObject((Node *) lfirst(ln)));
817 : }
818 6 : rowexpr = makeNode(RowExpr);
819 6 : rowexpr->args = fields;
820 6 : rowexpr->row_typeid = var->vartype;
821 6 : rowexpr->row_format = COERCE_IMPLICIT_CAST;
822 : /* vartype will always be RECORDOID, so we always need colnames */
823 6 : rowexpr->colnames = colnames;
824 6 : rowexpr->location = var->location;
825 :
826 : /* Lastly, add any varnullingrels to the replacement expression */
827 6 : return add_nullingrels_if_needed(context->root, (Node *) rowexpr,
828 : var);
829 : }
830 :
831 : /* Expand join alias reference */
832 : Assert(var->varattno > 0);
833 528 : newvar = (Node *) list_nth(rte->joinaliasvars, var->varattno - 1);
834 : Assert(newvar != NULL);
835 528 : newvar = copyObject(newvar);
836 :
837 : /*
838 : * If we are expanding an alias carried down from an upper query, must
839 : * adjust its varlevelsup fields.
840 : */
841 528 : if (context->sublevels_up != 0)
842 0 : IncrementVarSublevelsUp(newvar, context->sublevels_up, 0);
843 :
844 : /* Preserve original Var's location, if possible */
845 528 : if (IsA(newvar, Var))
846 0 : ((Var *) newvar)->location = var->location;
847 :
848 : /* Recurse in case join input is itself a join */
849 528 : newvar = flatten_join_alias_vars_mutator(newvar, context);
850 :
851 : /* Detect if we are adding a sublink to query */
852 528 : if (context->possible_sublink && !context->inserted_sublink)
853 0 : context->inserted_sublink = checkExprHasSubLink(newvar);
854 :
855 : /* Lastly, add any varnullingrels to the replacement expression */
856 528 : return add_nullingrels_if_needed(context->root, newvar, var);
857 : }
858 1553410 : if (IsA(node, PlaceHolderVar))
859 : {
860 : /* Copy the PlaceHolderVar node with correct mutation of subnodes */
861 : PlaceHolderVar *phv;
862 :
863 1660 : phv = (PlaceHolderVar *) expression_tree_mutator(node,
864 : flatten_join_alias_vars_mutator,
865 : (void *) context);
866 : /* now fix PlaceHolderVar's relid sets */
867 1660 : if (phv->phlevelsup == context->sublevels_up)
868 : {
869 1588 : phv->phrels = alias_relid_set(context->query,
870 : phv->phrels);
871 : /* we *don't* change phnullingrels */
872 : }
873 1660 : return (Node *) phv;
874 : }
875 :
876 1551750 : if (IsA(node, Query))
877 : {
878 : /* Recurse into RTE subquery or not-yet-planned sublink subquery */
879 : Query *newnode;
880 : bool save_inserted_sublink;
881 :
882 12444 : context->sublevels_up++;
883 12444 : save_inserted_sublink = context->inserted_sublink;
884 12444 : context->inserted_sublink = ((Query *) node)->hasSubLinks;
885 12444 : newnode = query_tree_mutator((Query *) node,
886 : flatten_join_alias_vars_mutator,
887 : (void *) context,
888 : QTW_IGNORE_JOINALIASES);
889 12444 : newnode->hasSubLinks |= context->inserted_sublink;
890 12444 : context->inserted_sublink = save_inserted_sublink;
891 12444 : context->sublevels_up--;
892 12444 : return (Node *) newnode;
893 : }
894 : /* Already-planned tree not supported */
895 : Assert(!IsA(node, SubPlan));
896 : /* Shouldn't need to handle these planner auxiliary nodes here */
897 : Assert(!IsA(node, SpecialJoinInfo));
898 : Assert(!IsA(node, PlaceHolderInfo));
899 : Assert(!IsA(node, MinMaxAggInfo));
900 :
901 1539306 : return expression_tree_mutator(node, flatten_join_alias_vars_mutator,
902 : (void *) context);
903 : }
904 :
905 : /*
906 : * Add oldvar's varnullingrels, if any, to a flattened join alias expression.
907 : * The newnode has been copied, so we can modify it freely.
908 : */
909 : static Node *
910 534 : add_nullingrels_if_needed(PlannerInfo *root, Node *newnode, Var *oldvar)
911 : {
912 534 : if (oldvar->varnullingrels == NULL)
913 378 : return newnode; /* nothing to do */
914 : /* If possible, do it by adding to existing nullingrel fields */
915 156 : if (is_standard_join_alias_expression(newnode, oldvar))
916 144 : adjust_standard_join_alias_expression(newnode, oldvar);
917 12 : else if (root)
918 : {
919 : /*
920 : * We can insert a PlaceHolderVar to carry the nullingrels. However,
921 : * deciding where to evaluate the PHV is slightly tricky. We first
922 : * try to evaluate it at the natural semantic level of the new
923 : * expression; but if that expression is variable-free, fall back to
924 : * evaluating it at the join that the oldvar is an alias Var for.
925 : */
926 : PlaceHolderVar *newphv;
927 12 : Index levelsup = oldvar->varlevelsup;
928 12 : Relids phrels = pull_varnos_of_level(root, newnode, levelsup);
929 :
930 12 : if (bms_is_empty(phrels)) /* variable-free? */
931 : {
932 12 : if (levelsup != 0) /* this won't work otherwise */
933 0 : elog(ERROR, "unsupported join alias expression");
934 12 : phrels = get_relids_for_join(root->parse, oldvar->varno);
935 : /* If it's an outer join, eval below not above the join */
936 12 : phrels = bms_del_member(phrels, oldvar->varno);
937 : Assert(!bms_is_empty(phrels));
938 : }
939 12 : newphv = make_placeholder_expr(root, (Expr *) newnode, phrels);
940 : /* newphv has zero phlevelsup and NULL phnullingrels; fix it */
941 12 : newphv->phlevelsup = levelsup;
942 12 : newphv->phnullingrels = bms_copy(oldvar->varnullingrels);
943 12 : newnode = (Node *) newphv;
944 : }
945 : else
946 : {
947 : /* ooops, we're missing support for something the parser can make */
948 0 : elog(ERROR, "unsupported join alias expression");
949 : }
950 156 : return newnode;
951 : }
952 :
953 : /*
954 : * Check to see if we can insert nullingrels into this join alias expression
955 : * without use of a separate PlaceHolderVar.
956 : *
957 : * This will handle Vars, PlaceHolderVars, and implicit-coercion and COALESCE
958 : * expressions built from those. This coverage needs to handle anything
959 : * that the parser would put into joinaliasvars.
960 : */
961 : static bool
962 468 : is_standard_join_alias_expression(Node *newnode, Var *oldvar)
963 : {
964 468 : if (newnode == NULL)
965 0 : return false;
966 468 : if (IsA(newnode, Var) &&
967 276 : ((Var *) newnode)->varlevelsup == oldvar->varlevelsup)
968 276 : return true;
969 192 : else if (IsA(newnode, PlaceHolderVar) &&
970 0 : ((PlaceHolderVar *) newnode)->phlevelsup == oldvar->varlevelsup)
971 0 : return true;
972 192 : else if (IsA(newnode, FuncExpr))
973 : {
974 30 : FuncExpr *fexpr = (FuncExpr *) newnode;
975 :
976 : /*
977 : * We need to assume that the function wouldn't produce non-NULL from
978 : * NULL, which is reasonable for implicit coercions but otherwise not
979 : * so much. (Looking at its strictness is likely overkill, and anyway
980 : * it would cause us to fail if someone forgot to mark an implicit
981 : * coercion as strict.)
982 : */
983 30 : if (fexpr->funcformat != COERCE_IMPLICIT_CAST ||
984 30 : fexpr->args == NIL)
985 0 : return false;
986 :
987 : /*
988 : * Examine only the first argument --- coercions might have additional
989 : * arguments that are constants.
990 : */
991 30 : return is_standard_join_alias_expression(linitial(fexpr->args), oldvar);
992 : }
993 162 : else if (IsA(newnode, RelabelType))
994 : {
995 18 : RelabelType *relabel = (RelabelType *) newnode;
996 :
997 : /* This definitely won't produce non-NULL from NULL */
998 18 : return is_standard_join_alias_expression((Node *) relabel->arg, oldvar);
999 : }
1000 144 : else if (IsA(newnode, CoerceViaIO))
1001 : {
1002 0 : CoerceViaIO *iocoerce = (CoerceViaIO *) newnode;
1003 :
1004 : /* This definitely won't produce non-NULL from NULL */
1005 0 : return is_standard_join_alias_expression((Node *) iocoerce->arg, oldvar);
1006 : }
1007 144 : else if (IsA(newnode, ArrayCoerceExpr))
1008 : {
1009 0 : ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) newnode;
1010 :
1011 : /* This definitely won't produce non-NULL from NULL (at array level) */
1012 0 : return is_standard_join_alias_expression((Node *) acoerce->arg, oldvar);
1013 : }
1014 144 : else if (IsA(newnode, CoalesceExpr))
1015 : {
1016 132 : CoalesceExpr *cexpr = (CoalesceExpr *) newnode;
1017 : ListCell *lc;
1018 :
1019 : Assert(cexpr->args != NIL);
1020 396 : foreach(lc, cexpr->args)
1021 : {
1022 264 : if (!is_standard_join_alias_expression(lfirst(lc), oldvar))
1023 0 : return false;
1024 : }
1025 132 : return true;
1026 : }
1027 : else
1028 12 : return false;
1029 : }
1030 :
1031 : /*
1032 : * Insert nullingrels into an expression accepted by
1033 : * is_standard_join_alias_expression.
1034 : */
1035 : static void
1036 444 : adjust_standard_join_alias_expression(Node *newnode, Var *oldvar)
1037 : {
1038 444 : if (IsA(newnode, Var) &&
1039 276 : ((Var *) newnode)->varlevelsup == oldvar->varlevelsup)
1040 276 : {
1041 276 : Var *newvar = (Var *) newnode;
1042 :
1043 276 : newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
1044 276 : oldvar->varnullingrels);
1045 : }
1046 168 : else if (IsA(newnode, PlaceHolderVar) &&
1047 0 : ((PlaceHolderVar *) newnode)->phlevelsup == oldvar->varlevelsup)
1048 0 : {
1049 0 : PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
1050 :
1051 0 : newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
1052 0 : oldvar->varnullingrels);
1053 : }
1054 168 : else if (IsA(newnode, FuncExpr))
1055 : {
1056 18 : FuncExpr *fexpr = (FuncExpr *) newnode;
1057 :
1058 18 : adjust_standard_join_alias_expression(linitial(fexpr->args), oldvar);
1059 : }
1060 150 : else if (IsA(newnode, RelabelType))
1061 : {
1062 18 : RelabelType *relabel = (RelabelType *) newnode;
1063 :
1064 18 : adjust_standard_join_alias_expression((Node *) relabel->arg, oldvar);
1065 : }
1066 132 : else if (IsA(newnode, CoerceViaIO))
1067 : {
1068 0 : CoerceViaIO *iocoerce = (CoerceViaIO *) newnode;
1069 :
1070 0 : adjust_standard_join_alias_expression((Node *) iocoerce->arg, oldvar);
1071 : }
1072 132 : else if (IsA(newnode, ArrayCoerceExpr))
1073 : {
1074 0 : ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) newnode;
1075 :
1076 0 : adjust_standard_join_alias_expression((Node *) acoerce->arg, oldvar);
1077 : }
1078 132 : else if (IsA(newnode, CoalesceExpr))
1079 : {
1080 132 : CoalesceExpr *cexpr = (CoalesceExpr *) newnode;
1081 : ListCell *lc;
1082 :
1083 : Assert(cexpr->args != NIL);
1084 396 : foreach(lc, cexpr->args)
1085 : {
1086 264 : adjust_standard_join_alias_expression(lfirst(lc), oldvar);
1087 : }
1088 : }
1089 : else
1090 : Assert(false);
1091 444 : }
1092 :
1093 : /*
1094 : * alias_relid_set: in a set of RT indexes, replace joins by their
1095 : * underlying base+OJ relids
1096 : */
1097 : static Relids
1098 1588 : alias_relid_set(Query *query, Relids relids)
1099 : {
1100 1588 : Relids result = NULL;
1101 : int rtindex;
1102 :
1103 1588 : rtindex = -1;
1104 4008 : while ((rtindex = bms_next_member(relids, rtindex)) >= 0)
1105 : {
1106 2420 : RangeTblEntry *rte = rt_fetch(rtindex, query->rtable);
1107 :
1108 2420 : if (rte->rtekind == RTE_JOIN)
1109 310 : result = bms_join(result, get_relids_for_join(query, rtindex));
1110 : else
1111 2110 : result = bms_add_member(result, rtindex);
1112 : }
1113 1588 : return result;
1114 : }
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