Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * prepjointree.c
4 : * Planner preprocessing for subqueries and join tree manipulation.
5 : *
6 : * NOTE: the intended sequence for invoking these operations is
7 : * replace_empty_jointree
8 : * pull_up_sublinks
9 : * preprocess_function_rtes
10 : * pull_up_subqueries
11 : * flatten_simple_union_all
12 : * do expression preprocessing (including flattening JOIN alias vars)
13 : * reduce_outer_joins
14 : * remove_useless_result_rtes
15 : *
16 : *
17 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
18 : * Portions Copyright (c) 1994, Regents of the University of California
19 : *
20 : *
21 : * IDENTIFICATION
22 : * src/backend/optimizer/prep/prepjointree.c
23 : *
24 : *-------------------------------------------------------------------------
25 : */
26 : #include "postgres.h"
27 :
28 : #include "catalog/pg_type.h"
29 : #include "funcapi.h"
30 : #include "miscadmin.h"
31 : #include "nodes/makefuncs.h"
32 : #include "nodes/multibitmapset.h"
33 : #include "nodes/nodeFuncs.h"
34 : #include "optimizer/clauses.h"
35 : #include "optimizer/optimizer.h"
36 : #include "optimizer/placeholder.h"
37 : #include "optimizer/prep.h"
38 : #include "optimizer/subselect.h"
39 : #include "optimizer/tlist.h"
40 : #include "parser/parse_relation.h"
41 : #include "parser/parsetree.h"
42 : #include "rewrite/rewriteManip.h"
43 :
44 :
45 : typedef struct pullup_replace_vars_context
46 : {
47 : PlannerInfo *root;
48 : List *targetlist; /* tlist of subquery being pulled up */
49 : RangeTblEntry *target_rte; /* RTE of subquery */
50 : Relids relids; /* relids within subquery, as numbered after
51 : * pullup (set only if target_rte->lateral) */
52 : bool *outer_hasSubLinks; /* -> outer query's hasSubLinks */
53 : int varno; /* varno of subquery */
54 : bool wrap_non_vars; /* do we need all non-Var outputs to be PHVs? */
55 : Node **rv_cache; /* cache for results with PHVs */
56 : } pullup_replace_vars_context;
57 :
58 : typedef struct reduce_outer_joins_pass1_state
59 : {
60 : Relids relids; /* base relids within this subtree */
61 : bool contains_outer; /* does subtree contain outer join(s)? */
62 : List *sub_states; /* List of states for subtree components */
63 : } reduce_outer_joins_pass1_state;
64 :
65 : typedef struct reduce_outer_joins_pass2_state
66 : {
67 : Relids inner_reduced; /* OJ relids reduced to plain inner joins */
68 : List *partial_reduced; /* List of partially reduced FULL joins */
69 : } reduce_outer_joins_pass2_state;
70 :
71 : typedef struct reduce_outer_joins_partial_state
72 : {
73 : int full_join_rti; /* RT index of a formerly-FULL join */
74 : Relids unreduced_side; /* relids in its still-nullable side */
75 : } reduce_outer_joins_partial_state;
76 :
77 : static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
78 : Relids *relids);
79 : static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
80 : Node **jtlink1, Relids available_rels1,
81 : Node **jtlink2, Relids available_rels2);
82 : static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
83 : JoinExpr *lowest_outer_join,
84 : AppendRelInfo *containing_appendrel);
85 : static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
86 : RangeTblEntry *rte,
87 : JoinExpr *lowest_outer_join,
88 : AppendRelInfo *containing_appendrel);
89 : static Node *pull_up_simple_union_all(PlannerInfo *root, Node *jtnode,
90 : RangeTblEntry *rte);
91 : static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
92 : int parentRTindex, Query *setOpQuery,
93 : int childRToffset);
94 : static void make_setop_translation_list(Query *query, int newvarno,
95 : AppendRelInfo *appinfo);
96 : static bool is_simple_subquery(PlannerInfo *root, Query *subquery,
97 : RangeTblEntry *rte,
98 : JoinExpr *lowest_outer_join);
99 : static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
100 : RangeTblEntry *rte);
101 : static bool is_simple_values(PlannerInfo *root, RangeTblEntry *rte);
102 : static Node *pull_up_constant_function(PlannerInfo *root, Node *jtnode,
103 : RangeTblEntry *rte,
104 : AppendRelInfo *containing_appendrel);
105 : static bool is_simple_union_all(Query *subquery);
106 : static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery,
107 : List *colTypes);
108 : static bool is_safe_append_member(Query *subquery);
109 : static bool jointree_contains_lateral_outer_refs(PlannerInfo *root,
110 : Node *jtnode, bool restricted,
111 : Relids safe_upper_varnos);
112 : static void perform_pullup_replace_vars(PlannerInfo *root,
113 : pullup_replace_vars_context *rvcontext,
114 : AppendRelInfo *containing_appendrel);
115 : static void replace_vars_in_jointree(Node *jtnode,
116 : pullup_replace_vars_context *context);
117 : static Node *pullup_replace_vars(Node *expr,
118 : pullup_replace_vars_context *context);
119 : static Node *pullup_replace_vars_callback(Var *var,
120 : replace_rte_variables_context *context);
121 : static Query *pullup_replace_vars_subquery(Query *query,
122 : pullup_replace_vars_context *context);
123 : static reduce_outer_joins_pass1_state *reduce_outer_joins_pass1(Node *jtnode);
124 : static void reduce_outer_joins_pass2(Node *jtnode,
125 : reduce_outer_joins_pass1_state *state1,
126 : reduce_outer_joins_pass2_state *state2,
127 : PlannerInfo *root,
128 : Relids nonnullable_rels,
129 : List *forced_null_vars);
130 : static void report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
131 : int rtindex, Relids relids);
132 : static Node *remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
133 : Node **parent_quals,
134 : Relids *dropped_outer_joins);
135 : static int get_result_relid(PlannerInfo *root, Node *jtnode);
136 : static void remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc);
137 : static bool find_dependent_phvs(PlannerInfo *root, int varno);
138 : static bool find_dependent_phvs_in_jointree(PlannerInfo *root,
139 : Node *node, int varno);
140 : static void substitute_phv_relids(Node *node,
141 : int varno, Relids subrelids);
142 : static void fix_append_rel_relids(PlannerInfo *root, int varno,
143 : Relids subrelids);
144 : static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
145 :
146 :
147 : /*
148 : * transform_MERGE_to_join
149 : * Replace a MERGE's jointree to also include the target relation.
150 : */
151 : void
152 491610 : transform_MERGE_to_join(Query *parse)
153 : {
154 : RangeTblEntry *joinrte;
155 : JoinExpr *joinexpr;
156 : bool have_action[NUM_MERGE_MATCH_KINDS];
157 : JoinType jointype;
158 : int joinrti;
159 : List *vars;
160 : RangeTblRef *rtr;
161 :
162 491610 : if (parse->commandType != CMD_MERGE)
163 489906 : return;
164 :
165 : /* XXX probably bogus */
166 1704 : vars = NIL;
167 :
168 : /*
169 : * Work out what kind of join is required. If there any WHEN NOT MATCHED
170 : * BY SOURCE/TARGET actions, an outer join is required so that we process
171 : * all unmatched tuples from the source and/or target relations.
172 : * Otherwise, we can use an inner join.
173 : */
174 1704 : have_action[MERGE_WHEN_MATCHED] = false;
175 1704 : have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = false;
176 1704 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = false;
177 :
178 6014 : foreach_node(MergeAction, action, parse->mergeActionList)
179 : {
180 2606 : if (action->commandType != CMD_NOTHING)
181 2558 : have_action[action->matchKind] = true;
182 : }
183 :
184 1704 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] &&
185 114 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
186 96 : jointype = JOIN_FULL;
187 1608 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
188 18 : jointype = JOIN_LEFT;
189 1590 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
190 730 : jointype = JOIN_RIGHT;
191 : else
192 860 : jointype = JOIN_INNER;
193 :
194 : /* Manufacture a join RTE to use. */
195 1704 : joinrte = makeNode(RangeTblEntry);
196 1704 : joinrte->rtekind = RTE_JOIN;
197 1704 : joinrte->jointype = jointype;
198 1704 : joinrte->joinmergedcols = 0;
199 1704 : joinrte->joinaliasvars = vars;
200 1704 : joinrte->joinleftcols = NIL; /* MERGE does not allow JOIN USING */
201 1704 : joinrte->joinrightcols = NIL; /* ditto */
202 1704 : joinrte->join_using_alias = NULL;
203 :
204 1704 : joinrte->alias = NULL;
205 1704 : joinrte->eref = makeAlias("*MERGE*", NIL);
206 1704 : joinrte->lateral = false;
207 1704 : joinrte->inh = false;
208 1704 : joinrte->inFromCl = true;
209 :
210 : /*
211 : * Add completed RTE to pstate's range table list, so that we know its
212 : * index.
213 : */
214 1704 : parse->rtable = lappend(parse->rtable, joinrte);
215 1704 : joinrti = list_length(parse->rtable);
216 :
217 : /*
218 : * Create a JOIN between the target and the source relation.
219 : *
220 : * Here the target is identified by parse->mergeTargetRelation. For a
221 : * regular table, this will equal parse->resultRelation, but for a
222 : * trigger-updatable view, it will be the expanded view subquery that we
223 : * need to pull data from.
224 : *
225 : * The source relation is in parse->jointree->fromlist, but any quals in
226 : * parse->jointree->quals are restrictions on the target relation (if the
227 : * target relation is an auto-updatable view).
228 : */
229 1704 : rtr = makeNode(RangeTblRef);
230 1704 : rtr->rtindex = parse->mergeTargetRelation;
231 1704 : joinexpr = makeNode(JoinExpr);
232 1704 : joinexpr->jointype = jointype;
233 1704 : joinexpr->isNatural = false;
234 1704 : joinexpr->larg = (Node *) makeFromExpr(list_make1(rtr), parse->jointree->quals);
235 1704 : joinexpr->rarg = linitial(parse->jointree->fromlist); /* source rel */
236 1704 : joinexpr->usingClause = NIL;
237 1704 : joinexpr->join_using_alias = NULL;
238 1704 : joinexpr->quals = parse->mergeJoinCondition;
239 1704 : joinexpr->alias = NULL;
240 1704 : joinexpr->rtindex = joinrti;
241 :
242 : /* Make the new join be the sole entry in the query's jointree */
243 1704 : parse->jointree->fromlist = list_make1(joinexpr);
244 1704 : parse->jointree->quals = NULL;
245 :
246 : /*
247 : * If necessary, mark parse->targetlist entries that refer to the target
248 : * as nullable by the join. Normally the targetlist will be empty for a
249 : * MERGE, but if the target is a trigger-updatable view, it will contain a
250 : * whole-row Var referring to the expanded view query.
251 : */
252 1704 : if (parse->targetList != NIL &&
253 30 : (jointype == JOIN_RIGHT || jointype == JOIN_FULL))
254 42 : parse->targetList = (List *)
255 42 : add_nulling_relids((Node *) parse->targetList,
256 42 : bms_make_singleton(parse->mergeTargetRelation),
257 42 : bms_make_singleton(joinrti));
258 :
259 : /*
260 : * If there are any WHEN NOT MATCHED BY SOURCE actions, the executor will
261 : * use the join condition to distinguish between MATCHED and NOT MATCHED
262 : * BY SOURCE cases. Otherwise, it's no longer needed, and we set it to
263 : * NULL, saving cycles during planning and execution.
264 : */
265 1704 : if (!have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
266 1590 : parse->mergeJoinCondition = NULL;
267 : }
268 :
269 : /*
270 : * replace_empty_jointree
271 : * If the Query's jointree is empty, replace it with a dummy RTE_RESULT
272 : * relation.
273 : *
274 : * By doing this, we can avoid a bunch of corner cases that formerly existed
275 : * for SELECTs with omitted FROM clauses. An example is that a subquery
276 : * with empty jointree previously could not be pulled up, because that would
277 : * have resulted in an empty relid set, making the subquery not uniquely
278 : * identifiable for join or PlaceHolderVar processing.
279 : *
280 : * Unlike most other functions in this file, this function doesn't recurse;
281 : * we rely on other processing to invoke it on sub-queries at suitable times.
282 : */
283 : void
284 523948 : replace_empty_jointree(Query *parse)
285 : {
286 : RangeTblEntry *rte;
287 : Index rti;
288 : RangeTblRef *rtr;
289 :
290 : /* Nothing to do if jointree is already nonempty */
291 523948 : if (parse->jointree->fromlist != NIL)
292 313604 : return;
293 :
294 : /* We mustn't change it in the top level of a setop tree, either */
295 215918 : if (parse->setOperations)
296 5574 : return;
297 :
298 : /* Create suitable RTE */
299 210344 : rte = makeNode(RangeTblEntry);
300 210344 : rte->rtekind = RTE_RESULT;
301 210344 : rte->eref = makeAlias("*RESULT*", NIL);
302 :
303 : /* Add it to rangetable */
304 210344 : parse->rtable = lappend(parse->rtable, rte);
305 210344 : rti = list_length(parse->rtable);
306 :
307 : /* And jam a reference into the jointree */
308 210344 : rtr = makeNode(RangeTblRef);
309 210344 : rtr->rtindex = rti;
310 210344 : parse->jointree->fromlist = list_make1(rtr);
311 : }
312 :
313 : /*
314 : * pull_up_sublinks
315 : * Attempt to pull up ANY and EXISTS SubLinks to be treated as
316 : * semijoins or anti-semijoins.
317 : *
318 : * A clause "foo op ANY (sub-SELECT)" can be processed by pulling the
319 : * sub-SELECT up to become a rangetable entry and treating the implied
320 : * comparisons as quals of a semijoin. However, this optimization *only*
321 : * works at the top level of WHERE or a JOIN/ON clause, because we cannot
322 : * distinguish whether the ANY ought to return FALSE or NULL in cases
323 : * involving NULL inputs. Also, in an outer join's ON clause we can only
324 : * do this if the sublink is degenerate (ie, references only the nullable
325 : * side of the join). In that case it is legal to push the semijoin
326 : * down into the nullable side of the join. If the sublink references any
327 : * nonnullable-side variables then it would have to be evaluated as part
328 : * of the outer join, which makes things way too complicated.
329 : *
330 : * Under similar conditions, EXISTS and NOT EXISTS clauses can be handled
331 : * by pulling up the sub-SELECT and creating a semijoin or anti-semijoin.
332 : *
333 : * This routine searches for such clauses and does the necessary parsetree
334 : * transformations if any are found.
335 : *
336 : * This routine has to run before preprocess_expression(), so the quals
337 : * clauses are not yet reduced to implicit-AND format, and are not guaranteed
338 : * to be AND/OR-flat either. That means we need to recursively search through
339 : * explicit AND clauses. We stop as soon as we hit a non-AND item.
340 : */
341 : void
342 29962 : pull_up_sublinks(PlannerInfo *root)
343 : {
344 : Node *jtnode;
345 : Relids relids;
346 :
347 : /* Begin recursion through the jointree */
348 29962 : jtnode = pull_up_sublinks_jointree_recurse(root,
349 29962 : (Node *) root->parse->jointree,
350 : &relids);
351 :
352 : /*
353 : * root->parse->jointree must always be a FromExpr, so insert a dummy one
354 : * if we got a bare RangeTblRef or JoinExpr out of the recursion.
355 : */
356 29962 : if (IsA(jtnode, FromExpr))
357 25674 : root->parse->jointree = (FromExpr *) jtnode;
358 : else
359 4288 : root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
360 29962 : }
361 :
362 : /*
363 : * Recurse through jointree nodes for pull_up_sublinks()
364 : *
365 : * In addition to returning the possibly-modified jointree node, we return
366 : * a relids set of the contained rels into *relids.
367 : */
368 : static Node *
369 100318 : pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
370 : Relids *relids)
371 : {
372 : /* Since this function recurses, it could be driven to stack overflow. */
373 100318 : check_stack_depth();
374 :
375 100318 : if (jtnode == NULL)
376 : {
377 0 : *relids = NULL;
378 : }
379 100318 : else if (IsA(jtnode, RangeTblRef))
380 : {
381 53812 : int varno = ((RangeTblRef *) jtnode)->rtindex;
382 :
383 53812 : *relids = bms_make_singleton(varno);
384 : /* jtnode is returned unmodified */
385 : }
386 46506 : else if (IsA(jtnode, FromExpr))
387 : {
388 30148 : FromExpr *f = (FromExpr *) jtnode;
389 30148 : List *newfromlist = NIL;
390 30148 : Relids frelids = NULL;
391 : FromExpr *newf;
392 : Node *jtlink;
393 : ListCell *l;
394 :
395 : /* First, recurse to process children and collect their relids */
396 63298 : foreach(l, f->fromlist)
397 : {
398 : Node *newchild;
399 : Relids childrelids;
400 :
401 33150 : newchild = pull_up_sublinks_jointree_recurse(root,
402 33150 : lfirst(l),
403 : &childrelids);
404 33150 : newfromlist = lappend(newfromlist, newchild);
405 33150 : frelids = bms_join(frelids, childrelids);
406 : }
407 : /* Build the replacement FromExpr; no quals yet */
408 30148 : newf = makeFromExpr(newfromlist, NULL);
409 : /* Set up a link representing the rebuilt jointree */
410 30148 : jtlink = (Node *) newf;
411 : /* Now process qual --- all children are available for use */
412 30148 : newf->quals = pull_up_sublinks_qual_recurse(root, f->quals,
413 : &jtlink, frelids,
414 : NULL, NULL);
415 :
416 : /*
417 : * Note that the result will be either newf, or a stack of JoinExprs
418 : * with newf at the base. We rely on subsequent optimization steps to
419 : * flatten this and rearrange the joins as needed.
420 : *
421 : * Although we could include the pulled-up subqueries in the returned
422 : * relids, there's no need since upper quals couldn't refer to their
423 : * outputs anyway.
424 : */
425 30148 : *relids = frelids;
426 30148 : jtnode = jtlink;
427 : }
428 16358 : else if (IsA(jtnode, JoinExpr))
429 : {
430 : JoinExpr *j;
431 : Relids leftrelids;
432 : Relids rightrelids;
433 : Node *jtlink;
434 :
435 : /*
436 : * Make a modifiable copy of join node, but don't bother copying its
437 : * subnodes (yet).
438 : */
439 16358 : j = (JoinExpr *) palloc(sizeof(JoinExpr));
440 16358 : memcpy(j, jtnode, sizeof(JoinExpr));
441 16358 : jtlink = (Node *) j;
442 :
443 : /* Recurse to process children and collect their relids */
444 16358 : j->larg = pull_up_sublinks_jointree_recurse(root, j->larg,
445 : &leftrelids);
446 16358 : j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg,
447 : &rightrelids);
448 :
449 : /*
450 : * Now process qual, showing appropriate child relids as available,
451 : * and attach any pulled-up jointree items at the right place. In the
452 : * inner-join case we put new JoinExprs above the existing one (much
453 : * as for a FromExpr-style join). In outer-join cases the new
454 : * JoinExprs must go into the nullable side of the outer join. The
455 : * point of the available_rels machinations is to ensure that we only
456 : * pull up quals for which that's okay.
457 : *
458 : * We don't expect to see any pre-existing JOIN_SEMI, JOIN_ANTI, or
459 : * JOIN_RIGHT_ANTI jointypes here.
460 : */
461 16358 : switch (j->jointype)
462 : {
463 7934 : case JOIN_INNER:
464 7934 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
465 : &jtlink,
466 : bms_union(leftrelids,
467 : rightrelids),
468 : NULL, NULL);
469 7934 : break;
470 8340 : case JOIN_LEFT:
471 8340 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
472 : &j->rarg,
473 : rightrelids,
474 : NULL, NULL);
475 8340 : break;
476 0 : case JOIN_FULL:
477 : /* can't do anything with full-join quals */
478 0 : break;
479 84 : case JOIN_RIGHT:
480 84 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
481 : &j->larg,
482 : leftrelids,
483 : NULL, NULL);
484 84 : break;
485 0 : default:
486 0 : elog(ERROR, "unrecognized join type: %d",
487 : (int) j->jointype);
488 : break;
489 : }
490 :
491 : /*
492 : * Although we could include the pulled-up subqueries in the returned
493 : * relids, there's no need since upper quals couldn't refer to their
494 : * outputs anyway. But we *do* need to include the join's own rtindex
495 : * because we haven't yet collapsed join alias variables, so upper
496 : * levels would mistakenly think they couldn't use references to this
497 : * join.
498 : */
499 16358 : *relids = bms_join(leftrelids, rightrelids);
500 16358 : if (j->rtindex)
501 16358 : *relids = bms_add_member(*relids, j->rtindex);
502 16358 : jtnode = jtlink;
503 : }
504 : else
505 0 : elog(ERROR, "unrecognized node type: %d",
506 : (int) nodeTag(jtnode));
507 100318 : return jtnode;
508 : }
509 :
510 : /*
511 : * Recurse through top-level qual nodes for pull_up_sublinks()
512 : *
513 : * jtlink1 points to the link in the jointree where any new JoinExprs should
514 : * be inserted if they reference available_rels1 (i.e., available_rels1
515 : * denotes the relations present underneath jtlink1). Optionally, jtlink2 can
516 : * point to a second link where new JoinExprs should be inserted if they
517 : * reference available_rels2 (pass NULL for both those arguments if not used).
518 : * Note that SubLinks referencing both sets of variables cannot be optimized.
519 : * If we find multiple pull-up-able SubLinks, they'll get stacked onto jtlink1
520 : * and/or jtlink2 in the order we encounter them. We rely on subsequent
521 : * optimization to rearrange the stack if appropriate.
522 : *
523 : * Returns the replacement qual node, or NULL if the qual should be removed.
524 : */
525 : static Node *
526 89682 : pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
527 : Node **jtlink1, Relids available_rels1,
528 : Node **jtlink2, Relids available_rels2)
529 : {
530 89682 : if (node == NULL)
531 6494 : return NULL;
532 83188 : if (IsA(node, SubLink))
533 : {
534 2284 : SubLink *sublink = (SubLink *) node;
535 : JoinExpr *j;
536 : Relids child_rels;
537 :
538 : /* Is it a convertible ANY or EXISTS clause? */
539 2284 : if (sublink->subLinkType == ANY_SUBLINK)
540 : {
541 1524 : if ((j = convert_ANY_sublink_to_join(root, sublink,
542 : available_rels1)) != NULL)
543 : {
544 : /* Yes; insert the new join node into the join tree */
545 1430 : j->larg = *jtlink1;
546 1430 : *jtlink1 = (Node *) j;
547 : /* Recursively process pulled-up jointree nodes */
548 1430 : j->rarg = pull_up_sublinks_jointree_recurse(root,
549 : j->rarg,
550 : &child_rels);
551 :
552 : /*
553 : * Now recursively process the pulled-up quals. Any inserted
554 : * joins can get stacked onto either j->larg or j->rarg,
555 : * depending on which rels they reference.
556 : */
557 1430 : j->quals = pull_up_sublinks_qual_recurse(root,
558 : j->quals,
559 : &j->larg,
560 : available_rels1,
561 : &j->rarg,
562 : child_rels);
563 : /* Return NULL representing constant TRUE */
564 1430 : return NULL;
565 : }
566 100 : if (available_rels2 != NULL &&
567 6 : (j = convert_ANY_sublink_to_join(root, sublink,
568 : available_rels2)) != NULL)
569 : {
570 : /* Yes; insert the new join node into the join tree */
571 0 : j->larg = *jtlink2;
572 0 : *jtlink2 = (Node *) j;
573 : /* Recursively process pulled-up jointree nodes */
574 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
575 : j->rarg,
576 : &child_rels);
577 :
578 : /*
579 : * Now recursively process the pulled-up quals. Any inserted
580 : * joins can get stacked onto either j->larg or j->rarg,
581 : * depending on which rels they reference.
582 : */
583 0 : j->quals = pull_up_sublinks_qual_recurse(root,
584 : j->quals,
585 : &j->larg,
586 : available_rels2,
587 : &j->rarg,
588 : child_rels);
589 : /* Return NULL representing constant TRUE */
590 0 : return NULL;
591 : }
592 : }
593 760 : else if (sublink->subLinkType == EXISTS_SUBLINK)
594 : {
595 700 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, false,
596 : available_rels1)) != NULL)
597 : {
598 : /* Yes; insert the new join node into the join tree */
599 594 : j->larg = *jtlink1;
600 594 : *jtlink1 = (Node *) j;
601 : /* Recursively process pulled-up jointree nodes */
602 594 : j->rarg = pull_up_sublinks_jointree_recurse(root,
603 : j->rarg,
604 : &child_rels);
605 :
606 : /*
607 : * Now recursively process the pulled-up quals. Any inserted
608 : * joins can get stacked onto either j->larg or j->rarg,
609 : * depending on which rels they reference.
610 : */
611 594 : j->quals = pull_up_sublinks_qual_recurse(root,
612 : j->quals,
613 : &j->larg,
614 : available_rels1,
615 : &j->rarg,
616 : child_rels);
617 : /* Return NULL representing constant TRUE */
618 594 : return NULL;
619 : }
620 138 : if (available_rels2 != NULL &&
621 32 : (j = convert_EXISTS_sublink_to_join(root, sublink, false,
622 : available_rels2)) != NULL)
623 : {
624 : /* Yes; insert the new join node into the join tree */
625 32 : j->larg = *jtlink2;
626 32 : *jtlink2 = (Node *) j;
627 : /* Recursively process pulled-up jointree nodes */
628 32 : j->rarg = pull_up_sublinks_jointree_recurse(root,
629 : j->rarg,
630 : &child_rels);
631 :
632 : /*
633 : * Now recursively process the pulled-up quals. Any inserted
634 : * joins can get stacked onto either j->larg or j->rarg,
635 : * depending on which rels they reference.
636 : */
637 32 : j->quals = pull_up_sublinks_qual_recurse(root,
638 : j->quals,
639 : &j->larg,
640 : available_rels2,
641 : &j->rarg,
642 : child_rels);
643 : /* Return NULL representing constant TRUE */
644 32 : return NULL;
645 : }
646 : }
647 : /* Else return it unmodified */
648 228 : return node;
649 : }
650 80904 : if (is_notclause(node))
651 : {
652 : /* If the immediate argument of NOT is EXISTS, try to convert */
653 6296 : SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
654 : JoinExpr *j;
655 : Relids child_rels;
656 :
657 6296 : if (sublink && IsA(sublink, SubLink))
658 : {
659 2544 : if (sublink->subLinkType == EXISTS_SUBLINK)
660 : {
661 2448 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, true,
662 : available_rels1)) != NULL)
663 : {
664 : /* Yes; insert the new join node into the join tree */
665 2434 : j->larg = *jtlink1;
666 2434 : *jtlink1 = (Node *) j;
667 : /* Recursively process pulled-up jointree nodes */
668 2434 : j->rarg = pull_up_sublinks_jointree_recurse(root,
669 : j->rarg,
670 : &child_rels);
671 :
672 : /*
673 : * Now recursively process the pulled-up quals. Because
674 : * we are underneath a NOT, we can't pull up sublinks that
675 : * reference the left-hand stuff, but it's still okay to
676 : * pull up sublinks referencing j->rarg.
677 : */
678 2434 : j->quals = pull_up_sublinks_qual_recurse(root,
679 : j->quals,
680 : &j->rarg,
681 : child_rels,
682 : NULL, NULL);
683 : /* Return NULL representing constant TRUE */
684 2434 : return NULL;
685 : }
686 14 : if (available_rels2 != NULL &&
687 0 : (j = convert_EXISTS_sublink_to_join(root, sublink, true,
688 : available_rels2)) != NULL)
689 : {
690 : /* Yes; insert the new join node into the join tree */
691 0 : j->larg = *jtlink2;
692 0 : *jtlink2 = (Node *) j;
693 : /* Recursively process pulled-up jointree nodes */
694 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
695 : j->rarg,
696 : &child_rels);
697 :
698 : /*
699 : * Now recursively process the pulled-up quals. Because
700 : * we are underneath a NOT, we can't pull up sublinks that
701 : * reference the left-hand stuff, but it's still okay to
702 : * pull up sublinks referencing j->rarg.
703 : */
704 0 : j->quals = pull_up_sublinks_qual_recurse(root,
705 : j->quals,
706 : &j->rarg,
707 : child_rels,
708 : NULL, NULL);
709 : /* Return NULL representing constant TRUE */
710 0 : return NULL;
711 : }
712 : }
713 : }
714 : /* Else return it unmodified */
715 3862 : return node;
716 : }
717 74608 : if (is_andclause(node))
718 : {
719 : /* Recurse into AND clause */
720 13550 : List *newclauses = NIL;
721 : ListCell *l;
722 :
723 52236 : foreach(l, ((BoolExpr *) node)->args)
724 : {
725 38686 : Node *oldclause = (Node *) lfirst(l);
726 : Node *newclause;
727 :
728 38686 : newclause = pull_up_sublinks_qual_recurse(root,
729 : oldclause,
730 : jtlink1,
731 : available_rels1,
732 : jtlink2,
733 : available_rels2);
734 38686 : if (newclause)
735 36186 : newclauses = lappend(newclauses, newclause);
736 : }
737 : /* We might have got back fewer clauses than we started with */
738 13550 : if (newclauses == NIL)
739 104 : return NULL;
740 13446 : else if (list_length(newclauses) == 1)
741 1030 : return (Node *) linitial(newclauses);
742 : else
743 12416 : return (Node *) make_andclause(newclauses);
744 : }
745 : /* Stop if not an AND */
746 61058 : return node;
747 : }
748 :
749 : /*
750 : * preprocess_function_rtes
751 : * Constant-simplify any FUNCTION RTEs in the FROM clause, and then
752 : * attempt to "inline" any that are set-returning functions.
753 : *
754 : * If an RTE_FUNCTION rtable entry invokes a set-returning function that
755 : * contains just a simple SELECT, we can convert the rtable entry to an
756 : * RTE_SUBQUERY entry exposing the SELECT directly. This is especially
757 : * useful if the subquery can then be "pulled up" for further optimization,
758 : * but we do it even if not, to reduce executor overhead.
759 : *
760 : * This has to be done before we have started to do any optimization of
761 : * subqueries, else any such steps wouldn't get applied to subqueries
762 : * obtained via inlining. However, we do it after pull_up_sublinks
763 : * so that we can inline any functions used in SubLink subselects.
764 : *
765 : * The reason for applying const-simplification at this stage is that
766 : * (a) we'd need to do it anyway to inline a SRF, and (b) by doing it now,
767 : * we can be sure that pull_up_constant_function() will see constants
768 : * if there are constants to be seen. This approach also guarantees
769 : * that every FUNCTION RTE has been const-simplified, allowing planner.c's
770 : * preprocess_expression() to skip doing it again.
771 : *
772 : * Like most of the planner, this feels free to scribble on its input data
773 : * structure.
774 : */
775 : void
776 520856 : preprocess_function_rtes(PlannerInfo *root)
777 : {
778 : ListCell *rt;
779 :
780 1330800 : foreach(rt, root->parse->rtable)
781 : {
782 809950 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
783 :
784 809950 : if (rte->rtekind == RTE_FUNCTION)
785 : {
786 : Query *funcquery;
787 :
788 : /* Apply const-simplification */
789 40556 : rte->functions = (List *)
790 40556 : eval_const_expressions(root, (Node *) rte->functions);
791 :
792 : /* Check safety of expansion, and expand if possible */
793 40556 : funcquery = inline_set_returning_function(root, rte);
794 40550 : if (funcquery)
795 : {
796 : /* Successful expansion, convert the RTE to a subquery */
797 150 : rte->rtekind = RTE_SUBQUERY;
798 150 : rte->subquery = funcquery;
799 150 : rte->security_barrier = false;
800 : /* Clear fields that should not be set in a subquery RTE */
801 150 : rte->functions = NIL;
802 150 : rte->funcordinality = false;
803 : }
804 : }
805 : }
806 520850 : }
807 :
808 : /*
809 : * pull_up_subqueries
810 : * Look for subqueries in the rangetable that can be pulled up into
811 : * the parent query. If the subquery has no special features like
812 : * grouping/aggregation then we can merge it into the parent's jointree.
813 : * Also, subqueries that are simple UNION ALL structures can be
814 : * converted into "append relations".
815 : */
816 : void
817 520850 : pull_up_subqueries(PlannerInfo *root)
818 : {
819 : /* Top level of jointree must always be a FromExpr */
820 : Assert(IsA(root->parse->jointree, FromExpr));
821 : /* Recursion starts with no containing join nor appendrel */
822 1041694 : root->parse->jointree = (FromExpr *)
823 520850 : pull_up_subqueries_recurse(root, (Node *) root->parse->jointree,
824 : NULL, NULL);
825 : /* We should still have a FromExpr */
826 : Assert(IsA(root->parse->jointree, FromExpr));
827 520844 : }
828 :
829 : /*
830 : * pull_up_subqueries_recurse
831 : * Recursive guts of pull_up_subqueries.
832 : *
833 : * This recursively processes the jointree and returns a modified jointree.
834 : *
835 : * If this jointree node is within either side of an outer join, then
836 : * lowest_outer_join references the lowest such JoinExpr node; otherwise
837 : * it is NULL. We use this to constrain the effects of LATERAL subqueries.
838 : *
839 : * If we are looking at a member subquery of an append relation,
840 : * containing_appendrel describes that relation; else it is NULL.
841 : * This forces use of the PlaceHolderVar mechanism for all non-Var targetlist
842 : * items, and puts some additional restrictions on what can be pulled up.
843 : *
844 : * A tricky aspect of this code is that if we pull up a subquery we have
845 : * to replace Vars that reference the subquery's outputs throughout the
846 : * parent query, including quals attached to jointree nodes above the one
847 : * we are currently processing! We handle this by being careful to maintain
848 : * validity of the jointree structure while recursing, in the following sense:
849 : * whenever we recurse, all qual expressions in the tree must be reachable
850 : * from the top level, in case the recursive call needs to modify them.
851 : *
852 : * Notice also that we can't turn pullup_replace_vars loose on the whole
853 : * jointree, because it'd return a mutated copy of the tree; we have to
854 : * invoke it just on the quals, instead. This behavior is what makes it
855 : * reasonable to pass lowest_outer_join as a pointer rather than some
856 : * more-indirect way of identifying the lowest OJ. Likewise, we don't
857 : * replace append_rel_list members but only their substructure, so the
858 : * containing_appendrel reference is safe to use.
859 : */
860 : static Node *
861 1251550 : pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
862 : JoinExpr *lowest_outer_join,
863 : AppendRelInfo *containing_appendrel)
864 : {
865 : /* Since this function recurses, it could be driven to stack overflow. */
866 1251550 : check_stack_depth();
867 : /* Also, since it's a bit expensive, let's check for query cancel. */
868 1251550 : CHECK_FOR_INTERRUPTS();
869 :
870 : Assert(jtnode != NULL);
871 1251550 : if (IsA(jtnode, RangeTblRef))
872 : {
873 644396 : int varno = ((RangeTblRef *) jtnode)->rtindex;
874 644396 : RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
875 :
876 : /*
877 : * Is this a subquery RTE, and if so, is the subquery simple enough to
878 : * pull up?
879 : *
880 : * If we are looking at an append-relation member, we can't pull it up
881 : * unless is_safe_append_member says so.
882 : */
883 682750 : if (rte->rtekind == RTE_SUBQUERY &&
884 68306 : is_simple_subquery(root, rte->subquery, rte, lowest_outer_join) &&
885 3738 : (containing_appendrel == NULL ||
886 3738 : is_safe_append_member(rte->subquery)))
887 29246 : return pull_up_simple_subquery(root, jtnode, rte,
888 : lowest_outer_join,
889 : containing_appendrel);
890 :
891 : /*
892 : * Alternatively, is it a simple UNION ALL subquery? If so, flatten
893 : * into an "append relation".
894 : *
895 : * It's safe to do this regardless of whether this query is itself an
896 : * appendrel member. (If you're thinking we should try to flatten the
897 : * two levels of appendrel together, you're right; but we handle that
898 : * in set_append_rel_pathlist, not here.)
899 : */
900 624258 : if (rte->rtekind == RTE_SUBQUERY &&
901 9108 : is_simple_union_all(rte->subquery))
902 1546 : return pull_up_simple_union_all(root, jtnode, rte);
903 :
904 : /*
905 : * Or perhaps it's a simple VALUES RTE?
906 : *
907 : * We don't allow VALUES pullup below an outer join nor into an
908 : * appendrel (such cases are impossible anyway at the moment).
909 : */
910 613604 : if (rte->rtekind == RTE_VALUES &&
911 9520 : lowest_outer_join == NULL &&
912 9520 : containing_appendrel == NULL &&
913 9520 : is_simple_values(root, rte))
914 1780 : return pull_up_simple_values(root, jtnode, rte);
915 :
916 : /*
917 : * Or perhaps it's a FUNCTION RTE that we could inline?
918 : */
919 611824 : if (rte->rtekind == RTE_FUNCTION)
920 40400 : return pull_up_constant_function(root, jtnode, rte,
921 : containing_appendrel);
922 :
923 : /* Otherwise, do nothing at this node. */
924 : }
925 607154 : else if (IsA(jtnode, FromExpr))
926 : {
927 526848 : FromExpr *f = (FromExpr *) jtnode;
928 : ListCell *l;
929 :
930 : Assert(containing_appendrel == NULL);
931 : /* Recursively transform all the child nodes */
932 1092574 : foreach(l, f->fromlist)
933 : {
934 565732 : lfirst(l) = pull_up_subqueries_recurse(root, lfirst(l),
935 : lowest_outer_join,
936 : NULL);
937 : }
938 : }
939 80306 : else if (IsA(jtnode, JoinExpr))
940 : {
941 80306 : JoinExpr *j = (JoinExpr *) jtnode;
942 :
943 : Assert(containing_appendrel == NULL);
944 : /* Recurse, being careful to tell myself when inside outer join */
945 80306 : switch (j->jointype)
946 : {
947 31120 : case JOIN_INNER:
948 31120 : j->larg = pull_up_subqueries_recurse(root, j->larg,
949 : lowest_outer_join,
950 : NULL);
951 31120 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
952 : lowest_outer_join,
953 : NULL);
954 31120 : break;
955 47082 : case JOIN_LEFT:
956 : case JOIN_SEMI:
957 : case JOIN_ANTI:
958 47082 : j->larg = pull_up_subqueries_recurse(root, j->larg,
959 : j,
960 : NULL);
961 47082 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
962 : j,
963 : NULL);
964 47082 : break;
965 1054 : case JOIN_FULL:
966 1054 : j->larg = pull_up_subqueries_recurse(root, j->larg,
967 : j,
968 : NULL);
969 1054 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
970 : j,
971 : NULL);
972 1054 : break;
973 1050 : case JOIN_RIGHT:
974 1050 : j->larg = pull_up_subqueries_recurse(root, j->larg,
975 : j,
976 : NULL);
977 1050 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
978 : j,
979 : NULL);
980 1050 : break;
981 0 : default:
982 0 : elog(ERROR, "unrecognized join type: %d",
983 : (int) j->jointype);
984 : break;
985 : }
986 : }
987 : else
988 0 : elog(ERROR, "unrecognized node type: %d",
989 : (int) nodeTag(jtnode));
990 1178572 : return jtnode;
991 : }
992 :
993 : /*
994 : * pull_up_simple_subquery
995 : * Attempt to pull up a single simple subquery.
996 : *
997 : * jtnode is a RangeTblRef that has been tentatively identified as a simple
998 : * subquery by pull_up_subqueries. We return the replacement jointree node,
999 : * or jtnode itself if we determine that the subquery can't be pulled up
1000 : * after all.
1001 : *
1002 : * rte is the RangeTblEntry referenced by jtnode. Remaining parameters are
1003 : * as for pull_up_subqueries_recurse.
1004 : */
1005 : static Node *
1006 29246 : pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
1007 : JoinExpr *lowest_outer_join,
1008 : AppendRelInfo *containing_appendrel)
1009 : {
1010 29246 : Query *parse = root->parse;
1011 29246 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1012 : Query *subquery;
1013 : PlannerInfo *subroot;
1014 : int rtoffset;
1015 : pullup_replace_vars_context rvcontext;
1016 : ListCell *lc;
1017 :
1018 : /*
1019 : * Make a modifiable copy of the subquery to hack on, so that the RTE will
1020 : * be left unchanged in case we decide below that we can't pull it up
1021 : * after all.
1022 : */
1023 29246 : subquery = copyObject(rte->subquery);
1024 :
1025 : /*
1026 : * Create a PlannerInfo data structure for this subquery.
1027 : *
1028 : * NOTE: the next few steps should match the first processing in
1029 : * subquery_planner(). Can we refactor to avoid code duplication, or
1030 : * would that just make things uglier?
1031 : */
1032 29246 : subroot = makeNode(PlannerInfo);
1033 29246 : subroot->parse = subquery;
1034 29246 : subroot->glob = root->glob;
1035 29246 : subroot->query_level = root->query_level;
1036 29246 : subroot->parent_root = root->parent_root;
1037 29246 : subroot->plan_params = NIL;
1038 29246 : subroot->outer_params = NULL;
1039 29246 : subroot->planner_cxt = CurrentMemoryContext;
1040 29246 : subroot->init_plans = NIL;
1041 29246 : subroot->cte_plan_ids = NIL;
1042 29246 : subroot->multiexpr_params = NIL;
1043 29246 : subroot->join_domains = NIL;
1044 29246 : subroot->eq_classes = NIL;
1045 29246 : subroot->ec_merging_done = false;
1046 29246 : subroot->last_rinfo_serial = 0;
1047 29246 : subroot->all_result_relids = NULL;
1048 29246 : subroot->leaf_result_relids = NULL;
1049 29246 : subroot->append_rel_list = NIL;
1050 29246 : subroot->row_identity_vars = NIL;
1051 29246 : subroot->rowMarks = NIL;
1052 29246 : memset(subroot->upper_rels, 0, sizeof(subroot->upper_rels));
1053 29246 : memset(subroot->upper_targets, 0, sizeof(subroot->upper_targets));
1054 29246 : subroot->processed_groupClause = NIL;
1055 29246 : subroot->processed_distinctClause = NIL;
1056 29246 : subroot->processed_tlist = NIL;
1057 29246 : subroot->update_colnos = NIL;
1058 29246 : subroot->grouping_map = NULL;
1059 29246 : subroot->minmax_aggs = NIL;
1060 29246 : subroot->qual_security_level = 0;
1061 29246 : subroot->placeholdersFrozen = false;
1062 29246 : subroot->hasRecursion = false;
1063 29246 : subroot->wt_param_id = -1;
1064 29246 : subroot->non_recursive_path = NULL;
1065 : /* We don't currently need a top JoinDomain for the subroot */
1066 :
1067 : /* No CTEs to worry about */
1068 : Assert(subquery->cteList == NIL);
1069 :
1070 : /*
1071 : * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
1072 : * that we don't need so many special cases to deal with that situation.
1073 : */
1074 29246 : replace_empty_jointree(subquery);
1075 :
1076 : /*
1077 : * Pull up any SubLinks within the subquery's quals, so that we don't
1078 : * leave unoptimized SubLinks behind.
1079 : */
1080 29246 : if (subquery->hasSubLinks)
1081 1862 : pull_up_sublinks(subroot);
1082 :
1083 : /*
1084 : * Similarly, preprocess its function RTEs to inline any set-returning
1085 : * functions in its rangetable.
1086 : */
1087 29246 : preprocess_function_rtes(subroot);
1088 :
1089 : /*
1090 : * Recursively pull up the subquery's subqueries, so that
1091 : * pull_up_subqueries' processing is complete for its jointree and
1092 : * rangetable.
1093 : *
1094 : * Note: it's okay that the subquery's recursion starts with NULL for
1095 : * containing-join info, even if we are within an outer join in the upper
1096 : * query; the lower query starts with a clean slate for outer-join
1097 : * semantics. Likewise, we needn't pass down appendrel state.
1098 : */
1099 29246 : pull_up_subqueries(subroot);
1100 :
1101 : /*
1102 : * Now we must recheck whether the subquery is still simple enough to pull
1103 : * up. If not, abandon processing it.
1104 : *
1105 : * We don't really need to recheck all the conditions involved, but it's
1106 : * easier just to keep this "if" looking the same as the one in
1107 : * pull_up_subqueries_recurse.
1108 : */
1109 29246 : if (is_simple_subquery(root, subquery, rte, lowest_outer_join) &&
1110 3032 : (containing_appendrel == NULL || is_safe_append_member(subquery)))
1111 : {
1112 : /* good to go */
1113 : }
1114 : else
1115 : {
1116 : /*
1117 : * Give up, return unmodified RangeTblRef.
1118 : *
1119 : * Note: The work we just did will be redone when the subquery gets
1120 : * planned on its own. Perhaps we could avoid that by storing the
1121 : * modified subquery back into the rangetable, but I'm not gonna risk
1122 : * it now.
1123 : */
1124 116 : return jtnode;
1125 : }
1126 :
1127 : /*
1128 : * We must flatten any join alias Vars in the subquery's targetlist,
1129 : * because pulling up the subquery's subqueries might have changed their
1130 : * expansions into arbitrary expressions, which could affect
1131 : * pullup_replace_vars' decisions about whether PlaceHolderVar wrappers
1132 : * are needed for tlist entries. (Likely it'd be better to do
1133 : * flatten_join_alias_vars on the whole query tree at some earlier stage,
1134 : * maybe even in the rewriter; but for now let's just fix this case here.)
1135 : */
1136 29130 : subquery->targetList = (List *)
1137 29130 : flatten_join_alias_vars(subroot, subroot->parse,
1138 29130 : (Node *) subquery->targetList);
1139 :
1140 : /*
1141 : * Adjust level-0 varnos in subquery so that we can append its rangetable
1142 : * to upper query's. We have to fix the subquery's append_rel_list as
1143 : * well.
1144 : */
1145 29130 : rtoffset = list_length(parse->rtable);
1146 29130 : OffsetVarNodes((Node *) subquery, rtoffset, 0);
1147 29130 : OffsetVarNodes((Node *) subroot->append_rel_list, rtoffset, 0);
1148 :
1149 : /*
1150 : * Upper-level vars in subquery are now one level closer to their parent
1151 : * than before.
1152 : */
1153 29130 : IncrementVarSublevelsUp((Node *) subquery, -1, 1);
1154 29130 : IncrementVarSublevelsUp((Node *) subroot->append_rel_list, -1, 1);
1155 :
1156 : /*
1157 : * The subquery's targetlist items are now in the appropriate form to
1158 : * insert into the top query, except that we may need to wrap them in
1159 : * PlaceHolderVars. Set up required context data for pullup_replace_vars.
1160 : * (Note that we should include the subquery's inner joins in relids,
1161 : * since it may include join alias vars referencing them.)
1162 : */
1163 29130 : rvcontext.root = root;
1164 29130 : rvcontext.targetlist = subquery->targetList;
1165 29130 : rvcontext.target_rte = rte;
1166 29130 : if (rte->lateral)
1167 788 : rvcontext.relids = get_relids_in_jointree((Node *) subquery->jointree,
1168 : true, true);
1169 : else /* won't need relids */
1170 28342 : rvcontext.relids = NULL;
1171 29130 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1172 29130 : rvcontext.varno = varno;
1173 : /* this flag will be set below, if needed */
1174 29130 : rvcontext.wrap_non_vars = false;
1175 : /* initialize cache array with indexes 0 .. length(tlist) */
1176 29130 : rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
1177 : sizeof(Node *));
1178 :
1179 : /*
1180 : * If we are dealing with an appendrel member then anything that's not a
1181 : * simple Var has to be turned into a PlaceHolderVar. We force this to
1182 : * ensure that what we pull up doesn't get merged into a surrounding
1183 : * expression during later processing and then fail to match the
1184 : * expression actually available from the appendrel.
1185 : */
1186 29130 : if (containing_appendrel != NULL)
1187 2916 : rvcontext.wrap_non_vars = true;
1188 :
1189 : /*
1190 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
1191 : * anything that's not a simple Var. Again, this ensures that expressions
1192 : * retain their separate identity so that they will match grouping set
1193 : * columns when appropriate. (It'd be sufficient to wrap values used in
1194 : * grouping set columns, and do so only in non-aggregated portions of the
1195 : * tlist and havingQual, but that would require a lot of infrastructure
1196 : * that pullup_replace_vars hasn't currently got.)
1197 : */
1198 29130 : if (parse->groupingSets)
1199 248 : rvcontext.wrap_non_vars = true;
1200 :
1201 : /*
1202 : * Replace all of the top query's references to the subquery's outputs
1203 : * with copies of the adjusted subtlist items, being careful not to
1204 : * replace any of the jointree structure.
1205 : */
1206 29130 : perform_pullup_replace_vars(root, &rvcontext,
1207 : containing_appendrel);
1208 :
1209 : /*
1210 : * If the subquery had a LATERAL marker, propagate that to any of its
1211 : * child RTEs that could possibly now contain lateral cross-references.
1212 : * The children might or might not contain any actual lateral
1213 : * cross-references, but we have to mark the pulled-up child RTEs so that
1214 : * later planner stages will check for such.
1215 : */
1216 29124 : if (rte->lateral)
1217 : {
1218 1936 : foreach(lc, subquery->rtable)
1219 : {
1220 1148 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(lc);
1221 :
1222 1148 : switch (child_rte->rtekind)
1223 : {
1224 534 : case RTE_RELATION:
1225 534 : if (child_rte->tablesample)
1226 30 : child_rte->lateral = true;
1227 534 : break;
1228 238 : case RTE_SUBQUERY:
1229 : case RTE_FUNCTION:
1230 : case RTE_VALUES:
1231 : case RTE_TABLEFUNC:
1232 238 : child_rte->lateral = true;
1233 238 : break;
1234 376 : case RTE_JOIN:
1235 : case RTE_CTE:
1236 : case RTE_NAMEDTUPLESTORE:
1237 : case RTE_RESULT:
1238 : /* these can't contain any lateral references */
1239 376 : break;
1240 : }
1241 1148 : }
1242 : }
1243 :
1244 : /*
1245 : * Now append the adjusted rtable entries and their perminfos to upper
1246 : * query. (We hold off until after fixing the upper rtable entries; no
1247 : * point in running that code on the subquery ones too.)
1248 : */
1249 29124 : CombineRangeTables(&parse->rtable, &parse->rteperminfos,
1250 : subquery->rtable, subquery->rteperminfos);
1251 :
1252 : /*
1253 : * Pull up any FOR UPDATE/SHARE markers, too. (OffsetVarNodes already
1254 : * adjusted the marker rtindexes, so just concat the lists.)
1255 : */
1256 29124 : parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
1257 :
1258 : /*
1259 : * We also have to fix the relid sets of any PlaceHolderVar nodes in the
1260 : * parent query. (This could perhaps be done by pullup_replace_vars(),
1261 : * but it seems cleaner to use two passes.) Note in particular that any
1262 : * PlaceHolderVar nodes just created by pullup_replace_vars() will be
1263 : * adjusted, so having created them with the subquery's varno is correct.
1264 : *
1265 : * Likewise, relids appearing in AppendRelInfo nodes have to be fixed. We
1266 : * already checked that this won't require introducing multiple subrelids
1267 : * into the single-slot AppendRelInfo structs.
1268 : */
1269 29124 : if (root->glob->lastPHId != 0 || root->append_rel_list)
1270 : {
1271 : Relids subrelids;
1272 :
1273 4344 : subrelids = get_relids_in_jointree((Node *) subquery->jointree,
1274 : true, false);
1275 4344 : if (root->glob->lastPHId != 0)
1276 1482 : substitute_phv_relids((Node *) parse, varno, subrelids);
1277 4344 : fix_append_rel_relids(root, varno, subrelids);
1278 : }
1279 :
1280 : /*
1281 : * And now add subquery's AppendRelInfos to our list.
1282 : */
1283 58248 : root->append_rel_list = list_concat(root->append_rel_list,
1284 29124 : subroot->append_rel_list);
1285 :
1286 : /*
1287 : * We don't have to do the equivalent bookkeeping for outer-join info,
1288 : * because that hasn't been set up yet. placeholder_list likewise.
1289 : */
1290 : Assert(root->join_info_list == NIL);
1291 : Assert(subroot->join_info_list == NIL);
1292 : Assert(root->placeholder_list == NIL);
1293 : Assert(subroot->placeholder_list == NIL);
1294 :
1295 : /*
1296 : * We no longer need the RTE's copy of the subquery's query tree. Getting
1297 : * rid of it saves nothing in particular so far as this level of query is
1298 : * concerned; but if this query level is in turn pulled up into a parent,
1299 : * we'd waste cycles copying the now-unused query tree.
1300 : */
1301 29124 : rte->subquery = NULL;
1302 :
1303 : /*
1304 : * Miscellaneous housekeeping.
1305 : *
1306 : * Although replace_rte_variables() faithfully updated parse->hasSubLinks
1307 : * if it copied any SubLinks out of the subquery's targetlist, we still
1308 : * could have SubLinks added to the query in the expressions of FUNCTION
1309 : * and VALUES RTEs copied up from the subquery. So it's necessary to copy
1310 : * subquery->hasSubLinks anyway. Perhaps this can be improved someday.
1311 : */
1312 29124 : parse->hasSubLinks |= subquery->hasSubLinks;
1313 :
1314 : /* If subquery had any RLS conditions, now main query does too */
1315 29124 : parse->hasRowSecurity |= subquery->hasRowSecurity;
1316 :
1317 : /*
1318 : * subquery won't be pulled up if it hasAggs, hasWindowFuncs, or
1319 : * hasTargetSRFs, so no work needed on those flags
1320 : */
1321 :
1322 : /*
1323 : * Return the adjusted subquery jointree to replace the RangeTblRef entry
1324 : * in parent's jointree; or, if the FromExpr is degenerate, just return
1325 : * its single member.
1326 : */
1327 : Assert(IsA(subquery->jointree, FromExpr));
1328 : Assert(subquery->jointree->fromlist != NIL);
1329 53584 : if (subquery->jointree->quals == NULL &&
1330 24460 : list_length(subquery->jointree->fromlist) == 1)
1331 24170 : return (Node *) linitial(subquery->jointree->fromlist);
1332 :
1333 4954 : return (Node *) subquery->jointree;
1334 : }
1335 :
1336 : /*
1337 : * pull_up_simple_union_all
1338 : * Pull up a single simple UNION ALL subquery.
1339 : *
1340 : * jtnode is a RangeTblRef that has been identified as a simple UNION ALL
1341 : * subquery by pull_up_subqueries. We pull up the leaf subqueries and
1342 : * build an "append relation" for the union set. The result value is just
1343 : * jtnode, since we don't actually need to change the query jointree.
1344 : */
1345 : static Node *
1346 1546 : pull_up_simple_union_all(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1347 : {
1348 1546 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1349 1546 : Query *subquery = rte->subquery;
1350 1546 : int rtoffset = list_length(root->parse->rtable);
1351 : List *rtable;
1352 :
1353 : /*
1354 : * Make a modifiable copy of the subquery's rtable, so we can adjust
1355 : * upper-level Vars in it. There are no such Vars in the setOperations
1356 : * tree proper, so fixing the rtable should be sufficient.
1357 : */
1358 1546 : rtable = copyObject(subquery->rtable);
1359 :
1360 : /*
1361 : * Upper-level vars in subquery are now one level closer to their parent
1362 : * than before. We don't have to worry about offsetting varnos, though,
1363 : * because the UNION leaf queries can't cross-reference each other.
1364 : */
1365 1546 : IncrementVarSublevelsUp_rtable(rtable, -1, 1);
1366 :
1367 : /*
1368 : * If the UNION ALL subquery had a LATERAL marker, propagate that to all
1369 : * its children. The individual children might or might not contain any
1370 : * actual lateral cross-references, but we have to mark the pulled-up
1371 : * child RTEs so that later planner stages will check for such.
1372 : */
1373 1546 : if (rte->lateral)
1374 : {
1375 : ListCell *rt;
1376 :
1377 198 : foreach(rt, rtable)
1378 : {
1379 132 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(rt);
1380 :
1381 : Assert(child_rte->rtekind == RTE_SUBQUERY);
1382 132 : child_rte->lateral = true;
1383 : }
1384 : }
1385 :
1386 : /*
1387 : * Append child RTEs (and their perminfos) to parent rtable.
1388 : */
1389 1546 : CombineRangeTables(&root->parse->rtable, &root->parse->rteperminfos,
1390 : rtable, subquery->rteperminfos);
1391 :
1392 : /*
1393 : * Recursively scan the subquery's setOperations tree and add
1394 : * AppendRelInfo nodes for leaf subqueries to the parent's
1395 : * append_rel_list. Also apply pull_up_subqueries to the leaf subqueries.
1396 : */
1397 : Assert(subquery->setOperations);
1398 1546 : pull_up_union_leaf_queries(subquery->setOperations, root, varno, subquery,
1399 : rtoffset);
1400 :
1401 : /*
1402 : * Mark the parent as an append relation.
1403 : */
1404 1546 : rte->inh = true;
1405 :
1406 1546 : return jtnode;
1407 : }
1408 :
1409 : /*
1410 : * pull_up_union_leaf_queries -- recursive guts of pull_up_simple_union_all
1411 : *
1412 : * Build an AppendRelInfo for each leaf query in the setop tree, and then
1413 : * apply pull_up_subqueries to the leaf query.
1414 : *
1415 : * Note that setOpQuery is the Query containing the setOp node, whose tlist
1416 : * contains references to all the setop output columns. When called from
1417 : * pull_up_simple_union_all, this is *not* the same as root->parse, which is
1418 : * the parent Query we are pulling up into.
1419 : *
1420 : * parentRTindex is the appendrel parent's index in root->parse->rtable.
1421 : *
1422 : * The child RTEs have already been copied to the parent. childRToffset
1423 : * tells us where in the parent's range table they were copied. When called
1424 : * from flatten_simple_union_all, childRToffset is 0 since the child RTEs
1425 : * were already in root->parse->rtable and no RT index adjustment is needed.
1426 : */
1427 : static void
1428 6842 : pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
1429 : Query *setOpQuery, int childRToffset)
1430 : {
1431 6842 : if (IsA(setOp, RangeTblRef))
1432 : {
1433 4356 : RangeTblRef *rtr = (RangeTblRef *) setOp;
1434 : int childRTindex;
1435 : AppendRelInfo *appinfo;
1436 :
1437 : /*
1438 : * Calculate the index in the parent's range table
1439 : */
1440 4356 : childRTindex = childRToffset + rtr->rtindex;
1441 :
1442 : /*
1443 : * Build a suitable AppendRelInfo, and attach to parent's list.
1444 : */
1445 4356 : appinfo = makeNode(AppendRelInfo);
1446 4356 : appinfo->parent_relid = parentRTindex;
1447 4356 : appinfo->child_relid = childRTindex;
1448 4356 : appinfo->parent_reltype = InvalidOid;
1449 4356 : appinfo->child_reltype = InvalidOid;
1450 4356 : make_setop_translation_list(setOpQuery, childRTindex, appinfo);
1451 4356 : appinfo->parent_reloid = InvalidOid;
1452 4356 : root->append_rel_list = lappend(root->append_rel_list, appinfo);
1453 :
1454 : /*
1455 : * Recursively apply pull_up_subqueries to the new child RTE. (We
1456 : * must build the AppendRelInfo first, because this will modify it;
1457 : * indeed, that's the only part of the upper query where Vars
1458 : * referencing childRTindex can exist at this point.)
1459 : *
1460 : * Note that we can pass NULL for containing-join info even if we're
1461 : * actually under an outer join, because the child's expressions
1462 : * aren't going to propagate up to the join. Also, we ignore the
1463 : * possibility that pull_up_subqueries_recurse() returns a different
1464 : * jointree node than what we pass it; if it does, the important thing
1465 : * is that it replaced the child relid in the AppendRelInfo node.
1466 : */
1467 4356 : rtr = makeNode(RangeTblRef);
1468 4356 : rtr->rtindex = childRTindex;
1469 4356 : (void) pull_up_subqueries_recurse(root, (Node *) rtr,
1470 : NULL, appinfo);
1471 : }
1472 2486 : else if (IsA(setOp, SetOperationStmt))
1473 : {
1474 2486 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1475 :
1476 : /* Recurse to reach leaf queries */
1477 2486 : pull_up_union_leaf_queries(op->larg, root, parentRTindex, setOpQuery,
1478 : childRToffset);
1479 2486 : pull_up_union_leaf_queries(op->rarg, root, parentRTindex, setOpQuery,
1480 : childRToffset);
1481 : }
1482 : else
1483 : {
1484 0 : elog(ERROR, "unrecognized node type: %d",
1485 : (int) nodeTag(setOp));
1486 : }
1487 6842 : }
1488 :
1489 : /*
1490 : * make_setop_translation_list
1491 : * Build the list of translations from parent Vars to child Vars for
1492 : * a UNION ALL member. (At this point it's just a simple list of
1493 : * referencing Vars, but if we succeed in pulling up the member
1494 : * subquery, the Vars will get replaced by pulled-up expressions.)
1495 : * Also create the rather trivial reverse-translation array.
1496 : */
1497 : static void
1498 4356 : make_setop_translation_list(Query *query, int newvarno,
1499 : AppendRelInfo *appinfo)
1500 : {
1501 4356 : List *vars = NIL;
1502 : AttrNumber *pcolnos;
1503 : ListCell *l;
1504 :
1505 : /* Initialize reverse-translation array with all entries zero */
1506 : /* (entries for resjunk columns will stay that way) */
1507 4356 : appinfo->num_child_cols = list_length(query->targetList);
1508 4356 : appinfo->parent_colnos = pcolnos =
1509 4356 : (AttrNumber *) palloc0(appinfo->num_child_cols * sizeof(AttrNumber));
1510 :
1511 13842 : foreach(l, query->targetList)
1512 : {
1513 9486 : TargetEntry *tle = (TargetEntry *) lfirst(l);
1514 :
1515 9486 : if (tle->resjunk)
1516 0 : continue;
1517 :
1518 9486 : vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
1519 9486 : pcolnos[tle->resno - 1] = tle->resno;
1520 : }
1521 :
1522 4356 : appinfo->translated_vars = vars;
1523 4356 : }
1524 :
1525 : /*
1526 : * is_simple_subquery
1527 : * Check a subquery in the range table to see if it's simple enough
1528 : * to pull up into the parent query.
1529 : *
1530 : * rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
1531 : * (Note subquery is not necessarily equal to rte->subquery; it could be a
1532 : * processed copy of that.)
1533 : * lowest_outer_join is the lowest outer join above the subquery, or NULL.
1534 : */
1535 : static bool
1536 67600 : is_simple_subquery(PlannerInfo *root, Query *subquery, RangeTblEntry *rte,
1537 : JoinExpr *lowest_outer_join)
1538 : {
1539 : /*
1540 : * Let's just make sure it's a valid subselect ...
1541 : */
1542 67600 : if (!IsA(subquery, Query) ||
1543 67600 : subquery->commandType != CMD_SELECT)
1544 0 : elog(ERROR, "subquery is bogus");
1545 :
1546 : /*
1547 : * Can't currently pull up a query with setops (unless it's simple UNION
1548 : * ALL, which is handled by a different code path). Maybe after querytree
1549 : * redesign...
1550 : */
1551 67600 : if (subquery->setOperations)
1552 2084 : return false;
1553 :
1554 : /*
1555 : * Can't pull up a subquery involving grouping, aggregation, SRFs,
1556 : * sorting, limiting, or WITH. (XXX WITH could possibly be allowed later)
1557 : *
1558 : * We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
1559 : * clauses, because pullup would cause the locking to occur semantically
1560 : * higher than it should. Implicit FOR UPDATE/SHARE is okay because in
1561 : * that case the locking was originally declared in the upper query
1562 : * anyway.
1563 : */
1564 65516 : if (subquery->hasAggs ||
1565 64076 : subquery->hasWindowFuncs ||
1566 63704 : subquery->hasTargetSRFs ||
1567 62132 : subquery->groupClause ||
1568 62076 : subquery->groupingSets ||
1569 62076 : subquery->havingQual ||
1570 62076 : subquery->sortClause ||
1571 61282 : subquery->distinctClause ||
1572 61032 : subquery->limitOffset ||
1573 60648 : subquery->limitCount ||
1574 60380 : subquery->hasForUpdate ||
1575 59918 : subquery->cteList)
1576 5748 : return false;
1577 :
1578 : /*
1579 : * Don't pull up if the RTE represents a security-barrier view; we
1580 : * couldn't prevent information leakage once the RTE's Vars are scattered
1581 : * about in the upper query.
1582 : */
1583 59768 : if (rte->security_barrier)
1584 318 : return false;
1585 :
1586 : /*
1587 : * If the subquery is LATERAL, check for pullup restrictions from that.
1588 : */
1589 59450 : if (rte->lateral)
1590 : {
1591 : bool restricted;
1592 : Relids safe_upper_varnos;
1593 :
1594 : /*
1595 : * The subquery's WHERE and JOIN/ON quals mustn't contain any lateral
1596 : * references to rels outside a higher outer join (including the case
1597 : * where the outer join is within the subquery itself). In such a
1598 : * case, pulling up would result in a situation where we need to
1599 : * postpone quals from below an outer join to above it, which is
1600 : * probably completely wrong and in any case is a complication that
1601 : * doesn't seem worth addressing at the moment.
1602 : */
1603 1642 : if (lowest_outer_join != NULL)
1604 : {
1605 660 : restricted = true;
1606 660 : safe_upper_varnos = get_relids_in_jointree((Node *) lowest_outer_join,
1607 : true, true);
1608 : }
1609 : else
1610 : {
1611 982 : restricted = false;
1612 982 : safe_upper_varnos = NULL; /* doesn't matter */
1613 : }
1614 :
1615 1642 : if (jointree_contains_lateral_outer_refs(root,
1616 1642 : (Node *) subquery->jointree,
1617 : restricted, safe_upper_varnos))
1618 12 : return false;
1619 :
1620 : /*
1621 : * If there's an outer join above the LATERAL subquery, also disallow
1622 : * pullup if the subquery's targetlist has any references to rels
1623 : * outside the outer join, since these might get pulled into quals
1624 : * above the subquery (but in or below the outer join) and then lead
1625 : * to qual-postponement issues similar to the case checked for above.
1626 : * (We wouldn't need to prevent pullup if no such references appear in
1627 : * outer-query quals, but we don't have enough info here to check
1628 : * that. Also, maybe this restriction could be removed if we forced
1629 : * such refs to be wrapped in PlaceHolderVars, even when they're below
1630 : * the nearest outer join? But it's a pretty hokey usage, so not
1631 : * clear this is worth sweating over.)
1632 : */
1633 1630 : if (lowest_outer_join != NULL)
1634 : {
1635 660 : Relids lvarnos = pull_varnos_of_level(root,
1636 660 : (Node *) subquery->targetList,
1637 : 1);
1638 :
1639 660 : if (!bms_is_subset(lvarnos, safe_upper_varnos))
1640 12 : return false;
1641 : }
1642 : }
1643 :
1644 : /*
1645 : * Don't pull up a subquery that has any volatile functions in its
1646 : * targetlist. Otherwise we might introduce multiple evaluations of these
1647 : * functions, if they get copied to multiple places in the upper query,
1648 : * leading to surprising results. (Note: the PlaceHolderVar mechanism
1649 : * doesn't quite guarantee single evaluation; else we could pull up anyway
1650 : * and just wrap such items in PlaceHolderVars ...)
1651 : */
1652 59426 : if (contain_volatile_functions((Node *) subquery->targetList))
1653 228 : return false;
1654 :
1655 59198 : return true;
1656 : }
1657 :
1658 : /*
1659 : * pull_up_simple_values
1660 : * Pull up a single simple VALUES RTE.
1661 : *
1662 : * jtnode is a RangeTblRef that has been identified as a simple VALUES RTE
1663 : * by pull_up_subqueries. We always return a RangeTblRef representing a
1664 : * RESULT RTE to replace it (all failure cases should have been detected by
1665 : * is_simple_values()). Actually, what we return is just jtnode, because
1666 : * we replace the VALUES RTE in the rangetable with the RESULT RTE.
1667 : *
1668 : * rte is the RangeTblEntry referenced by jtnode. Because of the limited
1669 : * possible usage of VALUES RTEs, we do not need the remaining parameters
1670 : * of pull_up_subqueries_recurse.
1671 : */
1672 : static Node *
1673 1780 : pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1674 : {
1675 1780 : Query *parse = root->parse;
1676 1780 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1677 : List *values_list;
1678 : List *tlist;
1679 : AttrNumber attrno;
1680 : pullup_replace_vars_context rvcontext;
1681 : ListCell *lc;
1682 :
1683 : Assert(rte->rtekind == RTE_VALUES);
1684 : Assert(list_length(rte->values_lists) == 1);
1685 :
1686 : /*
1687 : * Need a modifiable copy of the VALUES list to hack on, just in case it's
1688 : * multiply referenced.
1689 : */
1690 1780 : values_list = copyObject(linitial(rte->values_lists));
1691 :
1692 : /*
1693 : * The VALUES RTE can't contain any Vars of level zero, let alone any that
1694 : * are join aliases, so no need to flatten join alias Vars.
1695 : */
1696 : Assert(!contain_vars_of_level((Node *) values_list, 0));
1697 :
1698 : /*
1699 : * Set up required context data for pullup_replace_vars. In particular,
1700 : * we have to make the VALUES list look like a subquery targetlist.
1701 : */
1702 1780 : tlist = NIL;
1703 1780 : attrno = 1;
1704 4096 : foreach(lc, values_list)
1705 : {
1706 2316 : tlist = lappend(tlist,
1707 2316 : makeTargetEntry((Expr *) lfirst(lc),
1708 : attrno,
1709 : NULL,
1710 : false));
1711 2316 : attrno++;
1712 : }
1713 1780 : rvcontext.root = root;
1714 1780 : rvcontext.targetlist = tlist;
1715 1780 : rvcontext.target_rte = rte;
1716 1780 : rvcontext.relids = NULL;
1717 1780 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1718 1780 : rvcontext.varno = varno;
1719 1780 : rvcontext.wrap_non_vars = false;
1720 : /* initialize cache array with indexes 0 .. length(tlist) */
1721 1780 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
1722 : sizeof(Node *));
1723 :
1724 : /*
1725 : * Replace all of the top query's references to the RTE's outputs with
1726 : * copies of the adjusted VALUES expressions, being careful not to replace
1727 : * any of the jointree structure. We can assume there's no outer joins or
1728 : * appendrels in the dummy Query that surrounds a VALUES RTE.
1729 : */
1730 1780 : perform_pullup_replace_vars(root, &rvcontext, NULL);
1731 :
1732 : /*
1733 : * There should be no appendrels to fix, nor any outer joins and hence no
1734 : * PlaceHolderVars.
1735 : */
1736 : Assert(root->append_rel_list == NIL);
1737 : Assert(root->join_info_list == NIL);
1738 : Assert(root->placeholder_list == NIL);
1739 :
1740 : /*
1741 : * Replace the VALUES RTE with a RESULT RTE. The VALUES RTE is the only
1742 : * rtable entry in the current query level, so this is easy.
1743 : */
1744 : Assert(list_length(parse->rtable) == 1);
1745 :
1746 : /* Create suitable RTE */
1747 1780 : rte = makeNode(RangeTblEntry);
1748 1780 : rte->rtekind = RTE_RESULT;
1749 1780 : rte->eref = makeAlias("*RESULT*", NIL);
1750 :
1751 : /* Replace rangetable */
1752 1780 : parse->rtable = list_make1(rte);
1753 :
1754 : /* We could manufacture a new RangeTblRef, but the one we have is fine */
1755 : Assert(varno == 1);
1756 :
1757 1780 : return jtnode;
1758 : }
1759 :
1760 : /*
1761 : * is_simple_values
1762 : * Check a VALUES RTE in the range table to see if it's simple enough
1763 : * to pull up into the parent query.
1764 : *
1765 : * rte is the RTE_VALUES RangeTblEntry to check.
1766 : */
1767 : static bool
1768 9520 : is_simple_values(PlannerInfo *root, RangeTblEntry *rte)
1769 : {
1770 : Assert(rte->rtekind == RTE_VALUES);
1771 :
1772 : /*
1773 : * There must be exactly one VALUES list, else it's not semantically
1774 : * correct to replace the VALUES RTE with a RESULT RTE, nor would we have
1775 : * a unique set of expressions to substitute into the parent query.
1776 : */
1777 9520 : if (list_length(rte->values_lists) != 1)
1778 7740 : return false;
1779 :
1780 : /*
1781 : * Because VALUES can't appear under an outer join (or at least, we won't
1782 : * try to pull it up if it does), we need not worry about LATERAL, nor
1783 : * about validity of PHVs for the VALUES' outputs.
1784 : */
1785 :
1786 : /*
1787 : * Don't pull up a VALUES that contains any set-returning or volatile
1788 : * functions. The considerations here are basically identical to the
1789 : * restrictions on a pull-able subquery's targetlist.
1790 : */
1791 3560 : if (expression_returns_set((Node *) rte->values_lists) ||
1792 1780 : contain_volatile_functions((Node *) rte->values_lists))
1793 0 : return false;
1794 :
1795 : /*
1796 : * Do not pull up a VALUES that's not the only RTE in its parent query.
1797 : * This is actually the only case that the parser will generate at the
1798 : * moment, and assuming this is true greatly simplifies
1799 : * pull_up_simple_values().
1800 : */
1801 1780 : if (list_length(root->parse->rtable) != 1 ||
1802 1780 : rte != (RangeTblEntry *) linitial(root->parse->rtable))
1803 0 : return false;
1804 :
1805 1780 : return true;
1806 : }
1807 :
1808 : /*
1809 : * pull_up_constant_function
1810 : * Pull up an RTE_FUNCTION expression that was simplified to a constant.
1811 : *
1812 : * jtnode is a RangeTblRef that has been identified as a FUNCTION RTE by
1813 : * pull_up_subqueries. If its expression is just a Const, hoist that value
1814 : * up into the parent query, and replace the RTE_FUNCTION with RTE_RESULT.
1815 : *
1816 : * In principle we could pull up any immutable expression, but we don't.
1817 : * That might result in multiple evaluations of the expression, which could
1818 : * be costly if it's not just a Const. Also, the main value of this is
1819 : * to let the constant participate in further const-folding, and of course
1820 : * that won't happen for a non-Const.
1821 : *
1822 : * The pulled-up value might need to be wrapped in a PlaceHolderVar if the
1823 : * RTE is below an outer join or is part of an appendrel; the extra
1824 : * parameters show whether that's needed.
1825 : */
1826 : static Node *
1827 40400 : pull_up_constant_function(PlannerInfo *root, Node *jtnode,
1828 : RangeTblEntry *rte,
1829 : AppendRelInfo *containing_appendrel)
1830 : {
1831 40400 : Query *parse = root->parse;
1832 : RangeTblFunction *rtf;
1833 : TypeFuncClass functypclass;
1834 : Oid funcrettype;
1835 : TupleDesc tupdesc;
1836 : pullup_replace_vars_context rvcontext;
1837 :
1838 : /* Fail if the RTE has ORDINALITY - we don't implement that here. */
1839 40400 : if (rte->funcordinality)
1840 686 : return jtnode;
1841 :
1842 : /* Fail if RTE isn't a single, simple Const expr */
1843 39714 : if (list_length(rte->functions) != 1)
1844 72 : return jtnode;
1845 39642 : rtf = linitial_node(RangeTblFunction, rte->functions);
1846 39642 : if (!IsA(rtf->funcexpr, Const))
1847 39270 : return jtnode;
1848 :
1849 : /*
1850 : * If the function's result is not a scalar, we punt. In principle we
1851 : * could break the composite constant value apart into per-column
1852 : * constants, but for now it seems not worth the work.
1853 : */
1854 372 : if (rtf->funccolcount != 1)
1855 30 : return jtnode; /* definitely composite */
1856 :
1857 : /* If it has a coldeflist, it certainly returns RECORD */
1858 342 : if (rtf->funccolnames != NIL)
1859 0 : return jtnode; /* must be a one-column RECORD type */
1860 :
1861 342 : functypclass = get_expr_result_type(rtf->funcexpr,
1862 : &funcrettype,
1863 : &tupdesc);
1864 342 : if (functypclass != TYPEFUNC_SCALAR)
1865 12 : return jtnode; /* must be a one-column composite type */
1866 :
1867 : /* Create context for applying pullup_replace_vars */
1868 330 : rvcontext.root = root;
1869 330 : rvcontext.targetlist = list_make1(makeTargetEntry((Expr *) rtf->funcexpr,
1870 : 1, /* resno */
1871 : NULL, /* resname */
1872 : false)); /* resjunk */
1873 330 : rvcontext.target_rte = rte;
1874 :
1875 : /*
1876 : * Since this function was reduced to a Const, it doesn't contain any
1877 : * lateral references, even if it's marked as LATERAL. This means we
1878 : * don't need to fill relids.
1879 : */
1880 330 : rvcontext.relids = NULL;
1881 :
1882 330 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1883 330 : rvcontext.varno = ((RangeTblRef *) jtnode)->rtindex;
1884 : /* this flag will be set below, if needed */
1885 330 : rvcontext.wrap_non_vars = false;
1886 : /* initialize cache array with indexes 0 .. length(tlist) */
1887 330 : rvcontext.rv_cache = palloc0((list_length(rvcontext.targetlist) + 1) *
1888 : sizeof(Node *));
1889 :
1890 : /*
1891 : * If we are dealing with an appendrel member then anything that's not a
1892 : * simple Var has to be turned into a PlaceHolderVar. (See comments in
1893 : * pull_up_simple_subquery().)
1894 : */
1895 330 : if (containing_appendrel != NULL)
1896 0 : rvcontext.wrap_non_vars = true;
1897 :
1898 : /*
1899 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
1900 : * anything that's not a simple Var.
1901 : */
1902 330 : if (parse->groupingSets)
1903 0 : rvcontext.wrap_non_vars = true;
1904 :
1905 : /*
1906 : * Replace all of the top query's references to the RTE's output with
1907 : * copies of the funcexpr, being careful not to replace any of the
1908 : * jointree structure.
1909 : */
1910 330 : perform_pullup_replace_vars(root, &rvcontext,
1911 : containing_appendrel);
1912 :
1913 : /*
1914 : * We don't need to bother with changing PlaceHolderVars in the parent
1915 : * query. Their references to the RT index are still good for now, and
1916 : * will get removed later if we're able to drop the RTE_RESULT.
1917 : */
1918 :
1919 : /*
1920 : * Convert the RTE to be RTE_RESULT type, signifying that we don't need to
1921 : * scan it anymore, and zero out RTE_FUNCTION-specific fields. Also make
1922 : * sure the RTE is not marked LATERAL, since elsewhere we don't expect
1923 : * RTE_RESULTs to be LATERAL.
1924 : */
1925 330 : rte->rtekind = RTE_RESULT;
1926 330 : rte->functions = NIL;
1927 330 : rte->lateral = false;
1928 :
1929 : /*
1930 : * We can reuse the RangeTblRef node.
1931 : */
1932 330 : return jtnode;
1933 : }
1934 :
1935 : /*
1936 : * is_simple_union_all
1937 : * Check a subquery to see if it's a simple UNION ALL.
1938 : *
1939 : * We require all the setops to be UNION ALL (no mixing) and there can't be
1940 : * any datatype coercions involved, ie, all the leaf queries must emit the
1941 : * same datatypes.
1942 : */
1943 : static bool
1944 9108 : is_simple_union_all(Query *subquery)
1945 : {
1946 : SetOperationStmt *topop;
1947 :
1948 : /* Let's just make sure it's a valid subselect ... */
1949 9108 : if (!IsA(subquery, Query) ||
1950 9108 : subquery->commandType != CMD_SELECT)
1951 0 : elog(ERROR, "subquery is bogus");
1952 :
1953 : /* Is it a set-operation query at all? */
1954 9108 : topop = castNode(SetOperationStmt, subquery->setOperations);
1955 9108 : if (!topop)
1956 7024 : return false;
1957 :
1958 : /* Can't handle ORDER BY, LIMIT/OFFSET, locking, or WITH */
1959 2084 : if (subquery->sortClause ||
1960 2044 : subquery->limitOffset ||
1961 2044 : subquery->limitCount ||
1962 2044 : subquery->rowMarks ||
1963 2044 : subquery->cteList)
1964 126 : return false;
1965 :
1966 : /* Recursively check the tree of set operations */
1967 1958 : return is_simple_union_all_recurse((Node *) topop, subquery,
1968 : topop->colTypes);
1969 : }
1970 :
1971 : static bool
1972 13096 : is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes)
1973 : {
1974 : /* Since this function recurses, it could be driven to stack overflow. */
1975 13096 : check_stack_depth();
1976 :
1977 13096 : if (IsA(setOp, RangeTblRef))
1978 : {
1979 5362 : RangeTblRef *rtr = (RangeTblRef *) setOp;
1980 5362 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
1981 5362 : Query *subquery = rte->subquery;
1982 :
1983 : Assert(subquery != NULL);
1984 :
1985 : /* Leaf nodes are OK if they match the toplevel column types */
1986 : /* We don't have to compare typmods or collations here */
1987 5362 : return tlist_same_datatypes(subquery->targetList, colTypes, true);
1988 : }
1989 7734 : else if (IsA(setOp, SetOperationStmt))
1990 : {
1991 7734 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1992 :
1993 : /* Must be UNION ALL */
1994 7734 : if (op->op != SETOP_UNION || !op->all)
1995 4314 : return false;
1996 :
1997 : /* Recurse to check inputs */
1998 6372 : return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
1999 2952 : is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
2000 : }
2001 : else
2002 : {
2003 0 : elog(ERROR, "unrecognized node type: %d",
2004 : (int) nodeTag(setOp));
2005 : return false; /* keep compiler quiet */
2006 : }
2007 : }
2008 :
2009 : /*
2010 : * is_safe_append_member
2011 : * Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
2012 : * safe to pull up.
2013 : */
2014 : static bool
2015 6770 : is_safe_append_member(Query *subquery)
2016 : {
2017 : FromExpr *jtnode;
2018 :
2019 : /*
2020 : * It's only safe to pull up the child if its jointree contains exactly
2021 : * one RTE, else the AppendRelInfo data structure breaks. The one base RTE
2022 : * could be buried in several levels of FromExpr, however. Also, if the
2023 : * child's jointree is completely empty, we can pull up because
2024 : * pull_up_simple_subquery will insert a single RTE_RESULT RTE instead.
2025 : *
2026 : * Also, the child can't have any WHERE quals because there's no place to
2027 : * put them in an appendrel. (This is a bit annoying...) If we didn't
2028 : * need to check this, we'd just test whether get_relids_in_jointree()
2029 : * yields a singleton set, to be more consistent with the coding of
2030 : * fix_append_rel_relids().
2031 : */
2032 6770 : jtnode = subquery->jointree;
2033 : Assert(IsA(jtnode, FromExpr));
2034 : /* Check the completely-empty case */
2035 6770 : if (jtnode->fromlist == NIL && jtnode->quals == NULL)
2036 518 : return true;
2037 : /* Check the more general case */
2038 11848 : while (IsA(jtnode, FromExpr))
2039 : {
2040 6264 : if (jtnode->quals != NULL)
2041 668 : return false;
2042 5596 : if (list_length(jtnode->fromlist) != 1)
2043 0 : return false;
2044 5596 : jtnode = linitial(jtnode->fromlist);
2045 : }
2046 5584 : if (!IsA(jtnode, RangeTblRef))
2047 154 : return false;
2048 :
2049 5430 : return true;
2050 : }
2051 :
2052 : /*
2053 : * jointree_contains_lateral_outer_refs
2054 : * Check for disallowed lateral references in a jointree's quals
2055 : *
2056 : * If restricted is false, all level-1 Vars are allowed (but we still must
2057 : * search the jointree, since it might contain outer joins below which there
2058 : * will be restrictions). If restricted is true, return true when any qual
2059 : * in the jointree contains level-1 Vars coming from outside the rels listed
2060 : * in safe_upper_varnos.
2061 : */
2062 : static bool
2063 3738 : jointree_contains_lateral_outer_refs(PlannerInfo *root, Node *jtnode,
2064 : bool restricted,
2065 : Relids safe_upper_varnos)
2066 : {
2067 3738 : if (jtnode == NULL)
2068 0 : return false;
2069 3738 : if (IsA(jtnode, RangeTblRef))
2070 1794 : return false;
2071 1944 : else if (IsA(jtnode, FromExpr))
2072 : {
2073 1666 : FromExpr *f = (FromExpr *) jtnode;
2074 : ListCell *l;
2075 :
2076 : /* First, recurse to check child joins */
2077 3194 : foreach(l, f->fromlist)
2078 : {
2079 1540 : if (jointree_contains_lateral_outer_refs(root,
2080 1540 : lfirst(l),
2081 : restricted,
2082 : safe_upper_varnos))
2083 12 : return true;
2084 : }
2085 :
2086 : /* Then check the top-level quals */
2087 1654 : if (restricted &&
2088 684 : !bms_is_subset(pull_varnos_of_level(root, f->quals, 1),
2089 : safe_upper_varnos))
2090 0 : return true;
2091 : }
2092 278 : else if (IsA(jtnode, JoinExpr))
2093 : {
2094 278 : JoinExpr *j = (JoinExpr *) jtnode;
2095 :
2096 : /*
2097 : * If this is an outer join, we mustn't allow any upper lateral
2098 : * references in or below it.
2099 : */
2100 278 : if (j->jointype != JOIN_INNER)
2101 : {
2102 134 : restricted = true;
2103 134 : safe_upper_varnos = NULL;
2104 : }
2105 :
2106 : /* Check the child joins */
2107 278 : if (jointree_contains_lateral_outer_refs(root,
2108 : j->larg,
2109 : restricted,
2110 : safe_upper_varnos))
2111 0 : return true;
2112 278 : if (jointree_contains_lateral_outer_refs(root,
2113 : j->rarg,
2114 : restricted,
2115 : safe_upper_varnos))
2116 0 : return true;
2117 :
2118 : /* Check the JOIN's qual clauses */
2119 278 : if (restricted &&
2120 254 : !bms_is_subset(pull_varnos_of_level(root, j->quals, 1),
2121 : safe_upper_varnos))
2122 12 : return true;
2123 : }
2124 : else
2125 0 : elog(ERROR, "unrecognized node type: %d",
2126 : (int) nodeTag(jtnode));
2127 1920 : return false;
2128 : }
2129 :
2130 : /*
2131 : * Perform pullup_replace_vars everyplace it's needed in the query tree.
2132 : *
2133 : * Caller has already filled *rvcontext with data describing what to
2134 : * substitute for Vars referencing the target subquery. In addition
2135 : * we need the identity of the containing appendrel if any.
2136 : */
2137 : static void
2138 31240 : perform_pullup_replace_vars(PlannerInfo *root,
2139 : pullup_replace_vars_context *rvcontext,
2140 : AppendRelInfo *containing_appendrel)
2141 : {
2142 31240 : Query *parse = root->parse;
2143 : ListCell *lc;
2144 :
2145 : /*
2146 : * If we are considering an appendrel child subquery (that is, a UNION ALL
2147 : * member query that we're pulling up), then the only part of the upper
2148 : * query that could reference the child yet is the translated_vars list of
2149 : * the associated AppendRelInfo. Furthermore, we do not want to force use
2150 : * of PHVs in the AppendRelInfo --- there isn't any outer join between.
2151 : */
2152 31240 : if (containing_appendrel)
2153 : {
2154 2916 : bool save_wrap_non_vars = rvcontext->wrap_non_vars;
2155 :
2156 2916 : rvcontext->wrap_non_vars = false;
2157 2916 : containing_appendrel->translated_vars = (List *)
2158 2916 : pullup_replace_vars((Node *) containing_appendrel->translated_vars,
2159 : rvcontext);
2160 2916 : rvcontext->wrap_non_vars = save_wrap_non_vars;
2161 2916 : return;
2162 : }
2163 :
2164 : /*
2165 : * Replace all of the top query's references to the subquery's outputs
2166 : * with copies of the adjusted subtlist items, being careful not to
2167 : * replace any of the jointree structure. (This'd be a lot cleaner if we
2168 : * could use query_tree_mutator.) We have to use PHVs in the targetList,
2169 : * returningList, and havingQual, since those are certainly above any
2170 : * outer join. replace_vars_in_jointree tracks its location in the
2171 : * jointree and uses PHVs or not appropriately.
2172 : */
2173 28324 : parse->targetList = (List *)
2174 28324 : pullup_replace_vars((Node *) parse->targetList, rvcontext);
2175 28324 : parse->returningList = (List *)
2176 28324 : pullup_replace_vars((Node *) parse->returningList, rvcontext);
2177 :
2178 28324 : if (parse->onConflict)
2179 : {
2180 44 : parse->onConflict->onConflictSet = (List *)
2181 22 : pullup_replace_vars((Node *) parse->onConflict->onConflictSet,
2182 : rvcontext);
2183 22 : parse->onConflict->onConflictWhere =
2184 22 : pullup_replace_vars(parse->onConflict->onConflictWhere,
2185 : rvcontext);
2186 :
2187 : /*
2188 : * We assume ON CONFLICT's arbiterElems, arbiterWhere, exclRelTlist
2189 : * can't contain any references to a subquery.
2190 : */
2191 : }
2192 28324 : if (parse->mergeActionList)
2193 : {
2194 2584 : foreach(lc, parse->mergeActionList)
2195 : {
2196 1534 : MergeAction *action = lfirst(lc);
2197 :
2198 1534 : action->qual = pullup_replace_vars(action->qual, rvcontext);
2199 1534 : action->targetList = (List *)
2200 1534 : pullup_replace_vars((Node *) action->targetList, rvcontext);
2201 : }
2202 : }
2203 28324 : parse->mergeJoinCondition = pullup_replace_vars(parse->mergeJoinCondition,
2204 : rvcontext);
2205 28324 : replace_vars_in_jointree((Node *) parse->jointree, rvcontext);
2206 : Assert(parse->setOperations == NULL);
2207 28318 : parse->havingQual = pullup_replace_vars(parse->havingQual, rvcontext);
2208 :
2209 : /*
2210 : * Replace references in the translated_vars lists of appendrels.
2211 : */
2212 28330 : foreach(lc, root->append_rel_list)
2213 : {
2214 12 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(lc);
2215 :
2216 12 : appinfo->translated_vars = (List *)
2217 12 : pullup_replace_vars((Node *) appinfo->translated_vars, rvcontext);
2218 : }
2219 :
2220 : /*
2221 : * Replace references in the joinaliasvars lists of join RTEs.
2222 : */
2223 79938 : foreach(lc, parse->rtable)
2224 : {
2225 51620 : RangeTblEntry *otherrte = (RangeTblEntry *) lfirst(lc);
2226 :
2227 51620 : if (otherrte->rtekind == RTE_JOIN)
2228 5310 : otherrte->joinaliasvars = (List *)
2229 5310 : pullup_replace_vars((Node *) otherrte->joinaliasvars,
2230 : rvcontext);
2231 : }
2232 : }
2233 :
2234 : /*
2235 : * Helper routine for perform_pullup_replace_vars: do pullup_replace_vars on
2236 : * every expression in the jointree, without changing the jointree structure
2237 : * itself. Ugly, but there's no other way...
2238 : */
2239 : static void
2240 74116 : replace_vars_in_jointree(Node *jtnode,
2241 : pullup_replace_vars_context *context)
2242 : {
2243 74116 : if (jtnode == NULL)
2244 0 : return;
2245 74116 : if (IsA(jtnode, RangeTblRef))
2246 : {
2247 : /*
2248 : * If the RangeTblRef refers to a LATERAL subquery (that isn't the
2249 : * same subquery we're pulling up), it might contain references to the
2250 : * target subquery, which we must replace. We drive this from the
2251 : * jointree scan, rather than a scan of the rtable, so that we can
2252 : * avoid processing no-longer-referenced RTEs.
2253 : */
2254 37264 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2255 :
2256 37264 : if (varno != context->varno) /* ignore target subquery itself */
2257 : {
2258 8940 : RangeTblEntry *rte = rt_fetch(varno, context->root->parse->rtable);
2259 :
2260 : Assert(rte != context->target_rte);
2261 8940 : if (rte->lateral)
2262 : {
2263 828 : switch (rte->rtekind)
2264 : {
2265 0 : case RTE_RELATION:
2266 : /* shouldn't be marked LATERAL unless tablesample */
2267 : Assert(rte->tablesample);
2268 0 : rte->tablesample = (TableSampleClause *)
2269 0 : pullup_replace_vars((Node *) rte->tablesample,
2270 : context);
2271 0 : break;
2272 384 : case RTE_SUBQUERY:
2273 384 : rte->subquery =
2274 384 : pullup_replace_vars_subquery(rte->subquery,
2275 : context);
2276 384 : break;
2277 336 : case RTE_FUNCTION:
2278 336 : rte->functions = (List *)
2279 336 : pullup_replace_vars((Node *) rte->functions,
2280 : context);
2281 336 : break;
2282 108 : case RTE_TABLEFUNC:
2283 108 : rte->tablefunc = (TableFunc *)
2284 108 : pullup_replace_vars((Node *) rte->tablefunc,
2285 : context);
2286 108 : break;
2287 0 : case RTE_VALUES:
2288 0 : rte->values_lists = (List *)
2289 0 : pullup_replace_vars((Node *) rte->values_lists,
2290 : context);
2291 0 : break;
2292 0 : case RTE_JOIN:
2293 : case RTE_CTE:
2294 : case RTE_NAMEDTUPLESTORE:
2295 : case RTE_RESULT:
2296 : /* these shouldn't be marked LATERAL */
2297 : Assert(false);
2298 0 : break;
2299 : }
2300 37264 : }
2301 : }
2302 : }
2303 36852 : else if (IsA(jtnode, FromExpr))
2304 : {
2305 30606 : FromExpr *f = (FromExpr *) jtnode;
2306 : ListCell *l;
2307 :
2308 63906 : foreach(l, f->fromlist)
2309 33300 : replace_vars_in_jointree(lfirst(l), context);
2310 30606 : f->quals = pullup_replace_vars(f->quals, context);
2311 : }
2312 6246 : else if (IsA(jtnode, JoinExpr))
2313 : {
2314 6246 : JoinExpr *j = (JoinExpr *) jtnode;
2315 6246 : bool save_wrap_non_vars = context->wrap_non_vars;
2316 :
2317 6246 : replace_vars_in_jointree(j->larg, context);
2318 6246 : replace_vars_in_jointree(j->rarg, context);
2319 :
2320 : /*
2321 : * Use PHVs within the join quals of a full join. Otherwise, we
2322 : * cannot identify which side of the join a pulled-up var-free
2323 : * expression came from, which can lead to failure to make a plan at
2324 : * all because none of the quals appear to be mergeable or hashable
2325 : * conditions.
2326 : */
2327 6246 : if (j->jointype == JOIN_FULL)
2328 610 : context->wrap_non_vars = true;
2329 :
2330 6246 : j->quals = pullup_replace_vars(j->quals, context);
2331 :
2332 6246 : context->wrap_non_vars = save_wrap_non_vars;
2333 : }
2334 : else
2335 0 : elog(ERROR, "unrecognized node type: %d",
2336 : (int) nodeTag(jtnode));
2337 : }
2338 :
2339 : /*
2340 : * Apply pullup variable replacement throughout an expression tree
2341 : *
2342 : * Returns a modified copy of the tree, so this can't be used where we
2343 : * need to do in-place replacement.
2344 : */
2345 : static Node *
2346 161936 : pullup_replace_vars(Node *expr, pullup_replace_vars_context *context)
2347 : {
2348 161936 : return replace_rte_variables(expr,
2349 : context->varno, 0,
2350 : pullup_replace_vars_callback,
2351 : (void *) context,
2352 : context->outer_hasSubLinks);
2353 : }
2354 :
2355 : static Node *
2356 94970 : pullup_replace_vars_callback(Var *var,
2357 : replace_rte_variables_context *context)
2358 : {
2359 94970 : pullup_replace_vars_context *rcon = (pullup_replace_vars_context *) context->callback_arg;
2360 94970 : int varattno = var->varattno;
2361 : bool need_phv;
2362 : Node *newnode;
2363 :
2364 : /*
2365 : * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
2366 : * varnullingrels (unless we find below that the replacement expression is
2367 : * a Var or PlaceHolderVar that we can just add the nullingrels to). We
2368 : * also need one if the caller has instructed us that all non-Var/PHV
2369 : * replacements need to be wrapped for identification purposes.
2370 : */
2371 94970 : need_phv = (var->varnullingrels != NULL) || rcon->wrap_non_vars;
2372 :
2373 : /*
2374 : * If PlaceHolderVars are needed, we cache the modified expressions in
2375 : * rcon->rv_cache[]. This is not in hopes of any material speed gain
2376 : * within this function, but to avoid generating identical PHVs with
2377 : * different IDs. That would result in duplicate evaluations at runtime,
2378 : * and possibly prevent optimizations that rely on recognizing different
2379 : * references to the same subquery output as being equal(). So it's worth
2380 : * a bit of extra effort to avoid it.
2381 : *
2382 : * The cached items have phlevelsup = 0 and phnullingrels = NULL; we'll
2383 : * copy them and adjust those values for this reference site below.
2384 : */
2385 94970 : if (need_phv &&
2386 11876 : varattno >= InvalidAttrNumber &&
2387 11876 : varattno <= list_length(rcon->targetlist) &&
2388 11876 : rcon->rv_cache[varattno] != NULL)
2389 : {
2390 : /* Just copy the entry and fall through to adjust phlevelsup etc */
2391 1898 : newnode = copyObject(rcon->rv_cache[varattno]);
2392 : }
2393 93072 : else if (varattno == InvalidAttrNumber)
2394 : {
2395 : /* Must expand whole-tuple reference into RowExpr */
2396 : RowExpr *rowexpr;
2397 : List *colnames;
2398 : List *fields;
2399 490 : bool save_wrap_non_vars = rcon->wrap_non_vars;
2400 490 : int save_sublevelsup = context->sublevels_up;
2401 :
2402 : /*
2403 : * If generating an expansion for a var of a named rowtype (ie, this
2404 : * is a plain relation RTE), then we must include dummy items for
2405 : * dropped columns. If the var is RECORD (ie, this is a JOIN), then
2406 : * omit dropped columns. In the latter case, attach column names to
2407 : * the RowExpr for use of the executor and ruleutils.c.
2408 : *
2409 : * In order to be able to cache the results, we always generate the
2410 : * expansion with varlevelsup = 0, and then adjust below if needed.
2411 : */
2412 490 : expandRTE(rcon->target_rte,
2413 : var->varno, 0 /* not varlevelsup */ , var->location,
2414 490 : (var->vartype != RECORDOID),
2415 : &colnames, &fields);
2416 : /* Expand the generated per-field Vars, but don't insert PHVs there */
2417 490 : rcon->wrap_non_vars = false;
2418 490 : context->sublevels_up = 0; /* to match the expandRTE output */
2419 490 : fields = (List *) replace_rte_variables_mutator((Node *) fields,
2420 : context);
2421 490 : rcon->wrap_non_vars = save_wrap_non_vars;
2422 490 : context->sublevels_up = save_sublevelsup;
2423 :
2424 490 : rowexpr = makeNode(RowExpr);
2425 490 : rowexpr->args = fields;
2426 490 : rowexpr->row_typeid = var->vartype;
2427 490 : rowexpr->row_format = COERCE_IMPLICIT_CAST;
2428 490 : rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
2429 490 : rowexpr->location = var->location;
2430 490 : newnode = (Node *) rowexpr;
2431 :
2432 : /*
2433 : * Insert PlaceHolderVar if needed. Notice that we are wrapping one
2434 : * PlaceHolderVar around the whole RowExpr, rather than putting one
2435 : * around each element of the row. This is because we need the
2436 : * expression to yield NULL, not ROW(NULL,NULL,...) when it is forced
2437 : * to null by an outer join.
2438 : */
2439 490 : if (need_phv)
2440 : {
2441 : newnode = (Node *)
2442 30 : make_placeholder_expr(rcon->root,
2443 : (Expr *) newnode,
2444 : bms_make_singleton(rcon->varno));
2445 : /* cache it with the PHV, and with phlevelsup etc not set yet */
2446 30 : rcon->rv_cache[InvalidAttrNumber] = copyObject(newnode);
2447 : }
2448 : }
2449 : else
2450 : {
2451 : /* Normal case referencing one targetlist element */
2452 92582 : TargetEntry *tle = get_tle_by_resno(rcon->targetlist, varattno);
2453 :
2454 92582 : if (tle == NULL) /* shouldn't happen */
2455 0 : elog(ERROR, "could not find attribute %d in subquery targetlist",
2456 : varattno);
2457 :
2458 : /* Make a copy of the tlist item to return */
2459 92582 : newnode = (Node *) copyObject(tle->expr);
2460 :
2461 : /* Insert PlaceHolderVar if needed */
2462 92582 : if (need_phv)
2463 : {
2464 : bool wrap;
2465 :
2466 9948 : if (newnode && IsA(newnode, Var) &&
2467 8368 : ((Var *) newnode)->varlevelsup == 0)
2468 : {
2469 : /*
2470 : * Simple Vars always escape being wrapped, unless they are
2471 : * lateral references to something outside the subquery being
2472 : * pulled up. (Even then, we could omit the PlaceHolderVar if
2473 : * the referenced rel is under the same lowest outer join, but
2474 : * it doesn't seem worth the trouble to check that.)
2475 : */
2476 8352 : if (rcon->target_rte->lateral &&
2477 882 : !bms_is_member(((Var *) newnode)->varno, rcon->relids))
2478 66 : wrap = true;
2479 : else
2480 8286 : wrap = false;
2481 : }
2482 1596 : else if (newnode && IsA(newnode, PlaceHolderVar) &&
2483 144 : ((PlaceHolderVar *) newnode)->phlevelsup == 0)
2484 : {
2485 : /* The same rules apply for a PlaceHolderVar */
2486 144 : if (rcon->target_rte->lateral &&
2487 12 : !bms_is_subset(((PlaceHolderVar *) newnode)->phrels,
2488 12 : rcon->relids))
2489 12 : wrap = true;
2490 : else
2491 132 : wrap = false;
2492 : }
2493 : else
2494 : {
2495 : /*
2496 : * Must wrap, either because we need a place to insert
2497 : * varnullingrels or because caller told us to wrap
2498 : * everything.
2499 : */
2500 1452 : wrap = true;
2501 : }
2502 :
2503 9948 : if (wrap)
2504 : {
2505 : newnode = (Node *)
2506 1530 : make_placeholder_expr(rcon->root,
2507 : (Expr *) newnode,
2508 : bms_make_singleton(rcon->varno));
2509 :
2510 : /*
2511 : * Cache it if possible (ie, if the attno is in range, which
2512 : * it probably always should be).
2513 : */
2514 3060 : if (varattno > InvalidAttrNumber &&
2515 1530 : varattno <= list_length(rcon->targetlist))
2516 1530 : rcon->rv_cache[varattno] = copyObject(newnode);
2517 : }
2518 : }
2519 : }
2520 :
2521 : /* Must adjust varlevelsup if replaced Var is within a subquery */
2522 94970 : if (var->varlevelsup > 0)
2523 994 : IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
2524 :
2525 : /* Propagate any varnullingrels into the replacement Var or PHV */
2526 94970 : if (var->varnullingrels != NULL)
2527 : {
2528 10186 : if (IsA(newnode, Var))
2529 : {
2530 6848 : Var *newvar = (Var *) newnode;
2531 :
2532 : Assert(newvar->varlevelsup == var->varlevelsup);
2533 6848 : newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
2534 6848 : var->varnullingrels);
2535 : }
2536 3338 : else if (IsA(newnode, PlaceHolderVar))
2537 : {
2538 3338 : PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
2539 :
2540 : Assert(newphv->phlevelsup == var->varlevelsup);
2541 3338 : newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
2542 3338 : var->varnullingrels);
2543 : }
2544 : else
2545 0 : elog(ERROR, "failed to wrap a non-Var");
2546 : }
2547 :
2548 94970 : return newnode;
2549 : }
2550 :
2551 : /*
2552 : * Apply pullup variable replacement to a subquery
2553 : *
2554 : * This needs to be different from pullup_replace_vars() because
2555 : * replace_rte_variables will think that it shouldn't increment sublevels_up
2556 : * before entering the Query; so we need to call it with sublevels_up == 1.
2557 : */
2558 : static Query *
2559 384 : pullup_replace_vars_subquery(Query *query,
2560 : pullup_replace_vars_context *context)
2561 : {
2562 : Assert(IsA(query, Query));
2563 384 : return (Query *) replace_rte_variables((Node *) query,
2564 : context->varno, 1,
2565 : pullup_replace_vars_callback,
2566 : (void *) context,
2567 : NULL);
2568 : }
2569 :
2570 :
2571 : /*
2572 : * flatten_simple_union_all
2573 : * Try to optimize top-level UNION ALL structure into an appendrel
2574 : *
2575 : * If a query's setOperations tree consists entirely of simple UNION ALL
2576 : * operations, flatten it into an append relation, which we can process more
2577 : * intelligently than the general setops case. Otherwise, do nothing.
2578 : *
2579 : * In most cases, this can succeed only for a top-level query, because for a
2580 : * subquery in FROM, the parent query's invocation of pull_up_subqueries would
2581 : * already have flattened the UNION via pull_up_simple_union_all. But there
2582 : * are a few cases we can support here but not in that code path, for example
2583 : * when the subquery also contains ORDER BY.
2584 : */
2585 : void
2586 5574 : flatten_simple_union_all(PlannerInfo *root)
2587 : {
2588 5574 : Query *parse = root->parse;
2589 : SetOperationStmt *topop;
2590 : Node *leftmostjtnode;
2591 : int leftmostRTI;
2592 : RangeTblEntry *leftmostRTE;
2593 : int childRTI;
2594 : RangeTblEntry *childRTE;
2595 : RangeTblRef *rtr;
2596 :
2597 : /* Shouldn't be called unless query has setops */
2598 5574 : topop = castNode(SetOperationStmt, parse->setOperations);
2599 : Assert(topop);
2600 :
2601 : /* Can't optimize away a recursive UNION */
2602 5574 : if (root->hasRecursion)
2603 5250 : return;
2604 :
2605 : /*
2606 : * Recursively check the tree of set operations. If not all UNION ALL
2607 : * with identical column types, punt.
2608 : */
2609 4766 : if (!is_simple_union_all_recurse((Node *) topop, parse, topop->colTypes))
2610 4442 : return;
2611 :
2612 : /*
2613 : * Locate the leftmost leaf query in the setops tree. The upper query's
2614 : * Vars all refer to this RTE (see transformSetOperationStmt).
2615 : */
2616 324 : leftmostjtnode = topop->larg;
2617 532 : while (leftmostjtnode && IsA(leftmostjtnode, SetOperationStmt))
2618 208 : leftmostjtnode = ((SetOperationStmt *) leftmostjtnode)->larg;
2619 : Assert(leftmostjtnode && IsA(leftmostjtnode, RangeTblRef));
2620 324 : leftmostRTI = ((RangeTblRef *) leftmostjtnode)->rtindex;
2621 324 : leftmostRTE = rt_fetch(leftmostRTI, parse->rtable);
2622 : Assert(leftmostRTE->rtekind == RTE_SUBQUERY);
2623 :
2624 : /*
2625 : * Make a copy of the leftmost RTE and add it to the rtable. This copy
2626 : * will represent the leftmost leaf query in its capacity as a member of
2627 : * the appendrel. The original will represent the appendrel as a whole.
2628 : * (We must do things this way because the upper query's Vars have to be
2629 : * seen as referring to the whole appendrel.)
2630 : */
2631 324 : childRTE = copyObject(leftmostRTE);
2632 324 : parse->rtable = lappend(parse->rtable, childRTE);
2633 324 : childRTI = list_length(parse->rtable);
2634 :
2635 : /* Modify the setops tree to reference the child copy */
2636 324 : ((RangeTblRef *) leftmostjtnode)->rtindex = childRTI;
2637 :
2638 : /* Modify the formerly-leftmost RTE to mark it as an appendrel parent */
2639 324 : leftmostRTE->inh = true;
2640 :
2641 : /*
2642 : * Form a RangeTblRef for the appendrel, and insert it into FROM. The top
2643 : * Query of a setops tree should have had an empty FromClause initially.
2644 : */
2645 324 : rtr = makeNode(RangeTblRef);
2646 324 : rtr->rtindex = leftmostRTI;
2647 : Assert(parse->jointree->fromlist == NIL);
2648 324 : parse->jointree->fromlist = list_make1(rtr);
2649 :
2650 : /*
2651 : * Now pretend the query has no setops. We must do this before trying to
2652 : * do subquery pullup, because of Assert in pull_up_simple_subquery.
2653 : */
2654 324 : parse->setOperations = NULL;
2655 :
2656 : /*
2657 : * Build AppendRelInfo information, and apply pull_up_subqueries to the
2658 : * leaf queries of the UNION ALL. (We must do that now because they
2659 : * weren't previously referenced by the jointree, and so were missed by
2660 : * the main invocation of pull_up_subqueries.)
2661 : */
2662 324 : pull_up_union_leaf_queries((Node *) topop, root, leftmostRTI, parse, 0);
2663 : }
2664 :
2665 :
2666 : /*
2667 : * reduce_outer_joins
2668 : * Attempt to reduce outer joins to plain inner joins.
2669 : *
2670 : * The idea here is that given a query like
2671 : * SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
2672 : * we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
2673 : * is strict. The strict operator will always return NULL, causing the outer
2674 : * WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
2675 : * columns. Therefore, there's no need for the join to produce null-extended
2676 : * rows in the first place --- which makes it a plain join not an outer join.
2677 : * (This scenario may not be very likely in a query written out by hand, but
2678 : * it's reasonably likely when pushing quals down into complex views.)
2679 : *
2680 : * More generally, an outer join can be reduced in strength if there is a
2681 : * strict qual above it in the qual tree that constrains a Var from the
2682 : * nullable side of the join to be non-null. (For FULL joins this applies
2683 : * to each side separately.)
2684 : *
2685 : * Another transformation we apply here is to recognize cases like
2686 : * SELECT ... FROM a LEFT JOIN b ON (a.x = b.y) WHERE b.y IS NULL;
2687 : * If the join clause is strict for b.y, then only null-extended rows could
2688 : * pass the upper WHERE, and we can conclude that what the query is really
2689 : * specifying is an anti-semijoin. We change the join type from JOIN_LEFT
2690 : * to JOIN_ANTI. The IS NULL clause then becomes redundant, and must be
2691 : * removed to prevent bogus selectivity calculations, but we leave it to
2692 : * distribute_qual_to_rels to get rid of such clauses.
2693 : *
2694 : * Also, we get rid of JOIN_RIGHT cases by flipping them around to become
2695 : * JOIN_LEFT. This saves some code here and in some later planner routines;
2696 : * the main benefit is to reduce the number of jointypes that can appear in
2697 : * SpecialJoinInfo nodes. Note that we can still generate Paths and Plans
2698 : * that use JOIN_RIGHT (or JOIN_RIGHT_ANTI) by switching the inputs again.
2699 : *
2700 : * To ease recognition of strict qual clauses, we require this routine to be
2701 : * run after expression preprocessing (i.e., qual canonicalization and JOIN
2702 : * alias-var expansion).
2703 : */
2704 : void
2705 29534 : reduce_outer_joins(PlannerInfo *root)
2706 : {
2707 : reduce_outer_joins_pass1_state *state1;
2708 : reduce_outer_joins_pass2_state state2;
2709 : ListCell *lc;
2710 :
2711 : /*
2712 : * To avoid doing strictness checks on more quals than necessary, we want
2713 : * to stop descending the jointree as soon as there are no outer joins
2714 : * below our current point. This consideration forces a two-pass process.
2715 : * The first pass gathers information about which base rels appear below
2716 : * each side of each join clause, and about whether there are outer
2717 : * join(s) below each side of each join clause. The second pass examines
2718 : * qual clauses and changes join types as it descends the tree.
2719 : */
2720 29534 : state1 = reduce_outer_joins_pass1((Node *) root->parse->jointree);
2721 :
2722 : /* planner.c shouldn't have called me if no outer joins */
2723 29534 : if (state1 == NULL || !state1->contains_outer)
2724 0 : elog(ERROR, "so where are the outer joins?");
2725 :
2726 29534 : state2.inner_reduced = NULL;
2727 29534 : state2.partial_reduced = NIL;
2728 :
2729 29534 : reduce_outer_joins_pass2((Node *) root->parse->jointree,
2730 : state1, &state2,
2731 : root, NULL, NIL);
2732 :
2733 : /*
2734 : * If we successfully reduced the strength of any outer joins, we must
2735 : * remove references to those joins as nulling rels. This is handled as
2736 : * an additional pass, for simplicity and because we can handle all
2737 : * fully-reduced joins in a single pass over the parse tree.
2738 : */
2739 29534 : if (!bms_is_empty(state2.inner_reduced))
2740 : {
2741 1518 : root->parse = (Query *)
2742 1518 : remove_nulling_relids((Node *) root->parse,
2743 1518 : state2.inner_reduced,
2744 : NULL);
2745 : /* There could be references in the append_rel_list, too */
2746 1518 : root->append_rel_list = (List *)
2747 1518 : remove_nulling_relids((Node *) root->append_rel_list,
2748 1518 : state2.inner_reduced,
2749 : NULL);
2750 : }
2751 :
2752 : /*
2753 : * Partially-reduced full joins have to be done one at a time, since
2754 : * they'll each need a different setting of except_relids.
2755 : */
2756 29584 : foreach(lc, state2.partial_reduced)
2757 : {
2758 50 : reduce_outer_joins_partial_state *statep = lfirst(lc);
2759 50 : Relids full_join_relids = bms_make_singleton(statep->full_join_rti);
2760 :
2761 50 : root->parse = (Query *)
2762 50 : remove_nulling_relids((Node *) root->parse,
2763 : full_join_relids,
2764 50 : statep->unreduced_side);
2765 50 : root->append_rel_list = (List *)
2766 50 : remove_nulling_relids((Node *) root->append_rel_list,
2767 : full_join_relids,
2768 50 : statep->unreduced_side);
2769 : }
2770 29534 : }
2771 :
2772 : /*
2773 : * reduce_outer_joins_pass1 - phase 1 data collection
2774 : *
2775 : * Returns a state node describing the given jointree node.
2776 : */
2777 : static reduce_outer_joins_pass1_state *
2778 169128 : reduce_outer_joins_pass1(Node *jtnode)
2779 : {
2780 : reduce_outer_joins_pass1_state *result;
2781 :
2782 : result = (reduce_outer_joins_pass1_state *)
2783 169128 : palloc(sizeof(reduce_outer_joins_pass1_state));
2784 169128 : result->relids = NULL;
2785 169128 : result->contains_outer = false;
2786 169128 : result->sub_states = NIL;
2787 :
2788 169128 : if (jtnode == NULL)
2789 0 : return result;
2790 169128 : if (IsA(jtnode, RangeTblRef))
2791 : {
2792 84362 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2793 :
2794 84362 : result->relids = bms_make_singleton(varno);
2795 : }
2796 84766 : else if (IsA(jtnode, FromExpr))
2797 : {
2798 32468 : FromExpr *f = (FromExpr *) jtnode;
2799 : ListCell *l;
2800 :
2801 67466 : foreach(l, f->fromlist)
2802 : {
2803 : reduce_outer_joins_pass1_state *sub_state;
2804 :
2805 34998 : sub_state = reduce_outer_joins_pass1(lfirst(l));
2806 69996 : result->relids = bms_add_members(result->relids,
2807 34998 : sub_state->relids);
2808 34998 : result->contains_outer |= sub_state->contains_outer;
2809 34998 : result->sub_states = lappend(result->sub_states, sub_state);
2810 : }
2811 : }
2812 52298 : else if (IsA(jtnode, JoinExpr))
2813 : {
2814 52298 : JoinExpr *j = (JoinExpr *) jtnode;
2815 : reduce_outer_joins_pass1_state *sub_state;
2816 :
2817 : /* join's own RT index is not wanted in result->relids */
2818 52298 : if (IS_OUTER_JOIN(j->jointype))
2819 45056 : result->contains_outer = true;
2820 :
2821 52298 : sub_state = reduce_outer_joins_pass1(j->larg);
2822 104596 : result->relids = bms_add_members(result->relids,
2823 52298 : sub_state->relids);
2824 52298 : result->contains_outer |= sub_state->contains_outer;
2825 52298 : result->sub_states = lappend(result->sub_states, sub_state);
2826 :
2827 52298 : sub_state = reduce_outer_joins_pass1(j->rarg);
2828 104596 : result->relids = bms_add_members(result->relids,
2829 52298 : sub_state->relids);
2830 52298 : result->contains_outer |= sub_state->contains_outer;
2831 52298 : result->sub_states = lappend(result->sub_states, sub_state);
2832 : }
2833 : else
2834 0 : elog(ERROR, "unrecognized node type: %d",
2835 : (int) nodeTag(jtnode));
2836 169128 : return result;
2837 : }
2838 :
2839 : /*
2840 : * reduce_outer_joins_pass2 - phase 2 processing
2841 : *
2842 : * jtnode: current jointree node
2843 : * state1: state data collected by phase 1 for this node
2844 : * state2: where to accumulate info about successfully-reduced joins
2845 : * root: toplevel planner state
2846 : * nonnullable_rels: set of base relids forced non-null by upper quals
2847 : * forced_null_vars: multibitmapset of Vars forced null by upper quals
2848 : *
2849 : * Returns info in state2 about outer joins that were successfully simplified.
2850 : * Joins that were fully reduced to inner joins are all added to
2851 : * state2->inner_reduced. If a full join is reduced to a left join,
2852 : * it needs its own entry in state2->partial_reduced, since that will
2853 : * require custom processing to remove only the correct nullingrel markers.
2854 : */
2855 : static void
2856 76456 : reduce_outer_joins_pass2(Node *jtnode,
2857 : reduce_outer_joins_pass1_state *state1,
2858 : reduce_outer_joins_pass2_state *state2,
2859 : PlannerInfo *root,
2860 : Relids nonnullable_rels,
2861 : List *forced_null_vars)
2862 : {
2863 : /*
2864 : * pass 2 should never descend as far as an empty subnode or base rel,
2865 : * because it's only called on subtrees marked as contains_outer.
2866 : */
2867 76456 : if (jtnode == NULL)
2868 0 : elog(ERROR, "reached empty jointree");
2869 76456 : if (IsA(jtnode, RangeTblRef))
2870 0 : elog(ERROR, "reached base rel");
2871 76456 : else if (IsA(jtnode, FromExpr))
2872 : {
2873 30818 : FromExpr *f = (FromExpr *) jtnode;
2874 : ListCell *l;
2875 : ListCell *s;
2876 : Relids pass_nonnullable_rels;
2877 : List *pass_forced_null_vars;
2878 :
2879 : /* Scan quals to see if we can add any constraints */
2880 30818 : pass_nonnullable_rels = find_nonnullable_rels(f->quals);
2881 30818 : pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels,
2882 : nonnullable_rels);
2883 30818 : pass_forced_null_vars = find_forced_null_vars(f->quals);
2884 30818 : pass_forced_null_vars = mbms_add_members(pass_forced_null_vars,
2885 : forced_null_vars);
2886 : /* And recurse --- but only into interesting subtrees */
2887 : Assert(list_length(f->fromlist) == list_length(state1->sub_states));
2888 64040 : forboth(l, f->fromlist, s, state1->sub_states)
2889 : {
2890 33222 : reduce_outer_joins_pass1_state *sub_state = lfirst(s);
2891 :
2892 33222 : if (sub_state->contains_outer)
2893 30848 : reduce_outer_joins_pass2(lfirst(l), sub_state,
2894 : state2, root,
2895 : pass_nonnullable_rels,
2896 : pass_forced_null_vars);
2897 : }
2898 30818 : bms_free(pass_nonnullable_rels);
2899 : /* can't so easily clean up var lists, unfortunately */
2900 : }
2901 45638 : else if (IsA(jtnode, JoinExpr))
2902 : {
2903 45638 : JoinExpr *j = (JoinExpr *) jtnode;
2904 45638 : int rtindex = j->rtindex;
2905 45638 : JoinType jointype = j->jointype;
2906 45638 : reduce_outer_joins_pass1_state *left_state = linitial(state1->sub_states);
2907 45638 : reduce_outer_joins_pass1_state *right_state = lsecond(state1->sub_states);
2908 :
2909 : /* Can we simplify this join? */
2910 45638 : switch (jointype)
2911 : {
2912 546 : case JOIN_INNER:
2913 546 : break;
2914 42592 : case JOIN_LEFT:
2915 42592 : if (bms_overlap(nonnullable_rels, right_state->relids))
2916 1600 : jointype = JOIN_INNER;
2917 42592 : break;
2918 1050 : case JOIN_RIGHT:
2919 1050 : if (bms_overlap(nonnullable_rels, left_state->relids))
2920 50 : jointype = JOIN_INNER;
2921 1050 : break;
2922 1054 : case JOIN_FULL:
2923 1054 : if (bms_overlap(nonnullable_rels, left_state->relids))
2924 : {
2925 24 : if (bms_overlap(nonnullable_rels, right_state->relids))
2926 12 : jointype = JOIN_INNER;
2927 : else
2928 : {
2929 12 : jointype = JOIN_LEFT;
2930 : /* Also report partial reduction in state2 */
2931 12 : report_reduced_full_join(state2, rtindex,
2932 : right_state->relids);
2933 : }
2934 : }
2935 : else
2936 : {
2937 1030 : if (bms_overlap(nonnullable_rels, right_state->relids))
2938 : {
2939 38 : jointype = JOIN_RIGHT;
2940 : /* Also report partial reduction in state2 */
2941 38 : report_reduced_full_join(state2, rtindex,
2942 : left_state->relids);
2943 : }
2944 : }
2945 1054 : break;
2946 396 : case JOIN_SEMI:
2947 : case JOIN_ANTI:
2948 :
2949 : /*
2950 : * These could only have been introduced by pull_up_sublinks,
2951 : * so there's no way that upper quals could refer to their
2952 : * righthand sides, and no point in checking. We don't expect
2953 : * to see JOIN_RIGHT_ANTI yet.
2954 : */
2955 396 : break;
2956 0 : default:
2957 0 : elog(ERROR, "unrecognized join type: %d",
2958 : (int) jointype);
2959 : break;
2960 : }
2961 :
2962 : /*
2963 : * Convert JOIN_RIGHT to JOIN_LEFT. Note that in the case where we
2964 : * reduced JOIN_FULL to JOIN_RIGHT, this will mean the JoinExpr no
2965 : * longer matches the internal ordering of any CoalesceExpr's built to
2966 : * represent merged join variables. We don't care about that at
2967 : * present, but be wary of it ...
2968 : */
2969 45638 : if (jointype == JOIN_RIGHT)
2970 : {
2971 : Node *tmparg;
2972 :
2973 1038 : tmparg = j->larg;
2974 1038 : j->larg = j->rarg;
2975 1038 : j->rarg = tmparg;
2976 1038 : jointype = JOIN_LEFT;
2977 1038 : right_state = linitial(state1->sub_states);
2978 1038 : left_state = lsecond(state1->sub_states);
2979 : }
2980 :
2981 : /*
2982 : * See if we can reduce JOIN_LEFT to JOIN_ANTI. This is the case if
2983 : * the join's own quals are strict for any var that was forced null by
2984 : * higher qual levels. NOTE: there are other ways that we could
2985 : * detect an anti-join, in particular if we were to check whether Vars
2986 : * coming from the RHS must be non-null because of table constraints.
2987 : * That seems complicated and expensive though (in particular, one
2988 : * would have to be wary of lower outer joins). For the moment this
2989 : * seems sufficient.
2990 : */
2991 45638 : if (jointype == JOIN_LEFT)
2992 : {
2993 : List *nonnullable_vars;
2994 : Bitmapset *overlap;
2995 :
2996 : /* Find Vars in j->quals that must be non-null in joined rows */
2997 42042 : nonnullable_vars = find_nonnullable_vars(j->quals);
2998 :
2999 : /*
3000 : * It's not sufficient to check whether nonnullable_vars and
3001 : * forced_null_vars overlap: we need to know if the overlap
3002 : * includes any RHS variables.
3003 : */
3004 42042 : overlap = mbms_overlap_sets(nonnullable_vars, forced_null_vars);
3005 42042 : if (bms_overlap(overlap, right_state->relids))
3006 996 : jointype = JOIN_ANTI;
3007 : }
3008 :
3009 : /*
3010 : * Apply the jointype change, if any, to both jointree node and RTE.
3011 : * Also, if we changed an RTE to INNER, add its RTI to inner_reduced.
3012 : */
3013 45638 : if (rtindex && jointype != j->jointype)
3014 : {
3015 3708 : RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
3016 :
3017 : Assert(rte->rtekind == RTE_JOIN);
3018 : Assert(rte->jointype == j->jointype);
3019 3708 : rte->jointype = jointype;
3020 3708 : if (jointype == JOIN_INNER)
3021 1662 : state2->inner_reduced = bms_add_member(state2->inner_reduced,
3022 : rtindex);
3023 : }
3024 45638 : j->jointype = jointype;
3025 :
3026 : /* Only recurse if there's more to do below here */
3027 45638 : if (left_state->contains_outer || right_state->contains_outer)
3028 : {
3029 : Relids local_nonnullable_rels;
3030 : List *local_forced_null_vars;
3031 : Relids pass_nonnullable_rels;
3032 : List *pass_forced_null_vars;
3033 :
3034 : /*
3035 : * If this join is (now) inner, we can add any constraints its
3036 : * quals provide to those we got from above. But if it is outer,
3037 : * we can pass down the local constraints only into the nullable
3038 : * side, because an outer join never eliminates any rows from its
3039 : * non-nullable side. Also, there is no point in passing upper
3040 : * constraints into the nullable side, since if there were any
3041 : * we'd have been able to reduce the join. (In the case of upper
3042 : * forced-null constraints, we *must not* pass them into the
3043 : * nullable side --- they either applied here, or not.) The upshot
3044 : * is that we pass either the local or the upper constraints,
3045 : * never both, to the children of an outer join.
3046 : *
3047 : * Note that a SEMI join works like an inner join here: it's okay
3048 : * to pass down both local and upper constraints. (There can't be
3049 : * any upper constraints affecting its inner side, but it's not
3050 : * worth having a separate code path to avoid passing them.)
3051 : *
3052 : * At a FULL join we just punt and pass nothing down --- is it
3053 : * possible to be smarter?
3054 : */
3055 16008 : if (jointype != JOIN_FULL)
3056 : {
3057 15872 : local_nonnullable_rels = find_nonnullable_rels(j->quals);
3058 15872 : local_forced_null_vars = find_forced_null_vars(j->quals);
3059 15872 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3060 : {
3061 : /* OK to merge upper and local constraints */
3062 914 : local_nonnullable_rels = bms_add_members(local_nonnullable_rels,
3063 : nonnullable_rels);
3064 914 : local_forced_null_vars = mbms_add_members(local_forced_null_vars,
3065 : forced_null_vars);
3066 : }
3067 : }
3068 : else
3069 : {
3070 : /* no use in calculating these */
3071 136 : local_nonnullable_rels = NULL;
3072 136 : local_forced_null_vars = NIL;
3073 : }
3074 :
3075 16008 : if (left_state->contains_outer)
3076 : {
3077 15324 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3078 : {
3079 : /* pass union of local and upper constraints */
3080 700 : pass_nonnullable_rels = local_nonnullable_rels;
3081 700 : pass_forced_null_vars = local_forced_null_vars;
3082 : }
3083 14624 : else if (jointype != JOIN_FULL) /* ie, LEFT or ANTI */
3084 : {
3085 : /* can't pass local constraints to non-nullable side */
3086 14516 : pass_nonnullable_rels = nonnullable_rels;
3087 14516 : pass_forced_null_vars = forced_null_vars;
3088 : }
3089 : else
3090 : {
3091 : /* no constraints pass through JOIN_FULL */
3092 108 : pass_nonnullable_rels = NULL;
3093 108 : pass_forced_null_vars = NIL;
3094 : }
3095 15324 : reduce_outer_joins_pass2(j->larg, left_state,
3096 : state2, root,
3097 : pass_nonnullable_rels,
3098 : pass_forced_null_vars);
3099 : }
3100 :
3101 16008 : if (right_state->contains_outer)
3102 : {
3103 750 : if (jointype != JOIN_FULL) /* ie, INNER/LEFT/SEMI/ANTI */
3104 : {
3105 : /* pass appropriate constraints, per comment above */
3106 722 : pass_nonnullable_rels = local_nonnullable_rels;
3107 722 : pass_forced_null_vars = local_forced_null_vars;
3108 : }
3109 : else
3110 : {
3111 : /* no constraints pass through JOIN_FULL */
3112 28 : pass_nonnullable_rels = NULL;
3113 28 : pass_forced_null_vars = NIL;
3114 : }
3115 750 : reduce_outer_joins_pass2(j->rarg, right_state,
3116 : state2, root,
3117 : pass_nonnullable_rels,
3118 : pass_forced_null_vars);
3119 : }
3120 16008 : bms_free(local_nonnullable_rels);
3121 : }
3122 : }
3123 : else
3124 0 : elog(ERROR, "unrecognized node type: %d",
3125 : (int) nodeTag(jtnode));
3126 76456 : }
3127 :
3128 : /* Helper for reduce_outer_joins_pass2 */
3129 : static void
3130 50 : report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
3131 : int rtindex, Relids relids)
3132 : {
3133 : reduce_outer_joins_partial_state *statep;
3134 :
3135 50 : statep = palloc(sizeof(reduce_outer_joins_partial_state));
3136 50 : statep->full_join_rti = rtindex;
3137 50 : statep->unreduced_side = relids;
3138 50 : state2->partial_reduced = lappend(state2->partial_reduced, statep);
3139 50 : }
3140 :
3141 :
3142 : /*
3143 : * remove_useless_result_rtes
3144 : * Attempt to remove RTE_RESULT RTEs from the join tree.
3145 : * Also, elide single-child FromExprs where possible.
3146 : *
3147 : * We can remove RTE_RESULT entries from the join tree using the knowledge
3148 : * that RTE_RESULT returns exactly one row and has no output columns. Hence,
3149 : * if one is inner-joined to anything else, we can delete it. Optimizations
3150 : * are also possible for some outer-join cases, as detailed below.
3151 : *
3152 : * This pass also replaces single-child FromExprs with their child node
3153 : * where possible. It's appropriate to do that here and not earlier because
3154 : * RTE_RESULT removal might reduce a multiple-child FromExpr to have only one
3155 : * child. We can remove such a FromExpr if its quals are empty, or if it's
3156 : * semantically valid to merge the quals into those of the parent node.
3157 : * While removing unnecessary join tree nodes has some micro-efficiency value,
3158 : * the real reason to do this is to eliminate cases where the nullable side of
3159 : * an outer join node is a FromExpr whose single child is another outer join.
3160 : * To correctly determine whether the two outer joins can commute,
3161 : * deconstruct_jointree() must treat any quals of such a FromExpr as being
3162 : * degenerate quals of the upper outer join. The best way to do that is to
3163 : * make them actually *be* quals of the upper join, by dropping the FromExpr
3164 : * and hoisting the quals up into the upper join's quals. (Note that there is
3165 : * no hazard when the intermediate FromExpr has multiple children, since then
3166 : * it represents an inner join that cannot commute with the upper outer join.)
3167 : * As long as we have to do that, we might as well elide such FromExprs
3168 : * everywhere.
3169 : *
3170 : * Some of these optimizations depend on recognizing empty (constant-true)
3171 : * quals for FromExprs and JoinExprs. That makes it useful to apply this
3172 : * optimization pass after expression preprocessing, since that will have
3173 : * eliminated constant-true quals, allowing more cases to be recognized as
3174 : * optimizable. What's more, the usual reason for an RTE_RESULT to be present
3175 : * is that we pulled up a subquery or VALUES clause, thus very possibly
3176 : * replacing Vars with constants, making it more likely that a qual can be
3177 : * reduced to constant true. Also, because some optimizations depend on
3178 : * the outer-join type, it's best to have done reduce_outer_joins() first.
3179 : *
3180 : * A PlaceHolderVar referencing an RTE_RESULT RTE poses an obstacle to this
3181 : * process: we must remove the RTE_RESULT's relid from the PHV's phrels, but
3182 : * we must not reduce the phrels set to empty. If that would happen, and
3183 : * the RTE_RESULT is an immediate child of an outer join, we have to give up
3184 : * and not remove the RTE_RESULT: there is noplace else to evaluate the
3185 : * PlaceHolderVar. (That is, in such cases the RTE_RESULT *does* have output
3186 : * columns.) But if the RTE_RESULT is an immediate child of an inner join,
3187 : * we can usually change the PlaceHolderVar's phrels so as to evaluate it at
3188 : * the inner join instead. This is OK because we really only care that PHVs
3189 : * are evaluated above or below the correct outer joins. We can't, however,
3190 : * postpone the evaluation of a PHV to above where it is used; so there are
3191 : * some checks below on whether output PHVs are laterally referenced in the
3192 : * other join input rel(s).
3193 : *
3194 : * We used to try to do this work as part of pull_up_subqueries() where the
3195 : * potentially-optimizable cases get introduced; but it's way simpler, and
3196 : * more effective, to do it separately.
3197 : */
3198 : void
3199 237428 : remove_useless_result_rtes(PlannerInfo *root)
3200 : {
3201 237428 : Relids dropped_outer_joins = NULL;
3202 : ListCell *cell;
3203 :
3204 : /* Top level of jointree must always be a FromExpr */
3205 : Assert(IsA(root->parse->jointree, FromExpr));
3206 : /* Recurse ... */
3207 474856 : root->parse->jointree = (FromExpr *)
3208 237428 : remove_useless_results_recurse(root,
3209 237428 : (Node *) root->parse->jointree,
3210 : NULL,
3211 : &dropped_outer_joins);
3212 : /* We should still have a FromExpr */
3213 : Assert(IsA(root->parse->jointree, FromExpr));
3214 :
3215 : /*
3216 : * If we removed any outer-join nodes from the jointree, run around and
3217 : * remove references to those joins as nulling rels. (There could be such
3218 : * references in PHVs that we pulled up out of the original subquery that
3219 : * the RESULT rel replaced. This is kosher on the grounds that we now
3220 : * know that such an outer join wouldn't really have nulled anything.) We
3221 : * don't do this during the main recursion, for simplicity and because we
3222 : * can handle all such joins in a single pass over the parse tree.
3223 : */
3224 237428 : if (!bms_is_empty(dropped_outer_joins))
3225 : {
3226 60 : root->parse = (Query *)
3227 60 : remove_nulling_relids((Node *) root->parse,
3228 : dropped_outer_joins,
3229 : NULL);
3230 : /* There could be references in the append_rel_list, too */
3231 60 : root->append_rel_list = (List *)
3232 60 : remove_nulling_relids((Node *) root->append_rel_list,
3233 : dropped_outer_joins,
3234 : NULL);
3235 : }
3236 :
3237 : /*
3238 : * Remove any PlanRowMark referencing an RTE_RESULT RTE. We obviously
3239 : * must do that for any RTE_RESULT that we just removed. But one for a
3240 : * RTE that we did not remove can be dropped anyway: since the RTE has
3241 : * only one possible output row, there is no need for EPQ to mark and
3242 : * restore that row.
3243 : *
3244 : * It's necessary, not optional, to remove the PlanRowMark for a surviving
3245 : * RTE_RESULT RTE; otherwise we'll generate a whole-row Var for the
3246 : * RTE_RESULT, which the executor has no support for.
3247 : */
3248 239240 : foreach(cell, root->rowMarks)
3249 : {
3250 1812 : PlanRowMark *rc = (PlanRowMark *) lfirst(cell);
3251 :
3252 1812 : if (rt_fetch(rc->rti, root->parse->rtable)->rtekind == RTE_RESULT)
3253 776 : root->rowMarks = foreach_delete_current(root->rowMarks, cell);
3254 : }
3255 237428 : }
3256 :
3257 : /*
3258 : * remove_useless_results_recurse
3259 : * Recursive guts of remove_useless_result_rtes.
3260 : *
3261 : * This recursively processes the jointree and returns a modified jointree.
3262 : * In addition, the RT indexes of any removed outer-join nodes are added to
3263 : * *dropped_outer_joins.
3264 : *
3265 : * jtnode is the current jointree node. If it could be valid to merge
3266 : * its quals into those of the parent node, parent_quals should point to
3267 : * the parent's quals list; otherwise, pass NULL for parent_quals.
3268 : * (Note that in some cases, parent_quals points to the quals of a parent
3269 : * more than one level up in the tree.)
3270 : */
3271 : static Node *
3272 588828 : remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
3273 : Node **parent_quals,
3274 : Relids *dropped_outer_joins)
3275 : {
3276 : Assert(jtnode != NULL);
3277 588828 : if (IsA(jtnode, RangeTblRef))
3278 : {
3279 : /* Can't immediately do anything with a RangeTblRef */
3280 : }
3281 294852 : else if (IsA(jtnode, FromExpr))
3282 : {
3283 241422 : FromExpr *f = (FromExpr *) jtnode;
3284 241422 : Relids result_relids = NULL;
3285 : ListCell *cell;
3286 :
3287 : /*
3288 : * We can drop RTE_RESULT rels from the fromlist so long as at least
3289 : * one child remains, since joining to a one-row table changes
3290 : * nothing. (But we can't drop a RTE_RESULT that computes PHV(s) that
3291 : * are needed by some sibling. The cleanup transformation below would
3292 : * reassign the PHVs to be computed at the join, which is too late for
3293 : * the sibling's use.) The easiest way to mechanize this rule is to
3294 : * modify the list in-place.
3295 : */
3296 485962 : foreach(cell, f->fromlist)
3297 : {
3298 244540 : Node *child = (Node *) lfirst(cell);
3299 : int varno;
3300 :
3301 : /* Recursively transform child, allowing it to push up quals ... */
3302 244540 : child = remove_useless_results_recurse(root, child,
3303 : &f->quals,
3304 : dropped_outer_joins);
3305 : /* ... and stick it back into the tree */
3306 244540 : lfirst(cell) = child;
3307 :
3308 : /*
3309 : * If it's an RTE_RESULT with at least one sibling, and no sibling
3310 : * references dependent PHVs, we can drop it. We don't yet know
3311 : * what the inner join's final relid set will be, so postpone
3312 : * cleanup of PHVs etc till after this loop.
3313 : */
3314 249522 : if (list_length(f->fromlist) > 1 &&
3315 4982 : (varno = get_result_relid(root, child)) != 0 &&
3316 306 : !find_dependent_phvs_in_jointree(root, (Node *) f, varno))
3317 : {
3318 282 : f->fromlist = foreach_delete_current(f->fromlist, cell);
3319 282 : result_relids = bms_add_member(result_relids, varno);
3320 : }
3321 : }
3322 :
3323 : /*
3324 : * Clean up if we dropped any RTE_RESULT RTEs. This is a bit
3325 : * inefficient if there's more than one, but it seems better to
3326 : * optimize the support code for the single-relid case.
3327 : */
3328 241422 : if (result_relids)
3329 : {
3330 270 : int varno = -1;
3331 :
3332 552 : while ((varno = bms_next_member(result_relids, varno)) >= 0)
3333 282 : remove_result_refs(root, varno, (Node *) f);
3334 : }
3335 :
3336 : /*
3337 : * If the FromExpr now has only one child, see if we can elide it.
3338 : * This is always valid if there are no quals, except at the top of
3339 : * the jointree (since Query.jointree is required to point to a
3340 : * FromExpr). Otherwise, we can do it if we can push the quals up to
3341 : * the parent node.
3342 : *
3343 : * Note: while it would not be terribly hard to generalize this
3344 : * transformation to merge multi-child FromExprs into their parent
3345 : * FromExpr, that risks making the parent join too expensive to plan.
3346 : * We leave it to later processing to decide heuristically whether
3347 : * that's a good idea. Pulling up a single child is always OK,
3348 : * however.
3349 : */
3350 241422 : if (list_length(f->fromlist) == 1 &&
3351 239726 : f != root->parse->jointree &&
3352 3808 : (f->quals == NULL || parent_quals != NULL))
3353 : {
3354 : /*
3355 : * Merge any quals up to parent. They should be in implicit-AND
3356 : * format by now, so we just need to concatenate lists. Put the
3357 : * child quals at the front, on the grounds that they should
3358 : * nominally be evaluated earlier.
3359 : */
3360 2620 : if (f->quals != NULL)
3361 1292 : *parent_quals = (Node *)
3362 1292 : list_concat(castNode(List, f->quals),
3363 : castNode(List, *parent_quals));
3364 2620 : return (Node *) linitial(f->fromlist);
3365 : }
3366 : }
3367 53430 : else if (IsA(jtnode, JoinExpr))
3368 : {
3369 53430 : JoinExpr *j = (JoinExpr *) jtnode;
3370 : int varno;
3371 :
3372 : /*
3373 : * First, recurse. We can absorb pushed-up FromExpr quals from either
3374 : * child into this node if the jointype is INNER, since then this is
3375 : * equivalent to a FromExpr. When the jointype is LEFT, we can absorb
3376 : * quals from the RHS child into the current node, as they're
3377 : * essentially degenerate quals of the outer join. Moreover, if we've
3378 : * been passed down a parent_quals pointer then we can allow quals of
3379 : * the LHS child to be absorbed into the parent. (This is important
3380 : * to ensure we remove single-child FromExprs immediately below
3381 : * commutable left joins.) For other jointypes, we can't move child
3382 : * quals up, or at least there's no particular reason to.
3383 : */
3384 53430 : j->larg = remove_useless_results_recurse(root, j->larg,
3385 53430 : (j->jointype == JOIN_INNER) ?
3386 : &j->quals :
3387 43996 : (j->jointype == JOIN_LEFT) ?
3388 43996 : parent_quals : NULL,
3389 : dropped_outer_joins);
3390 53430 : j->rarg = remove_useless_results_recurse(root, j->rarg,
3391 53430 : (j->jointype == JOIN_INNER ||
3392 43996 : j->jointype == JOIN_LEFT) ?
3393 : &j->quals : NULL,
3394 : dropped_outer_joins);
3395 :
3396 : /* Apply join-type-specific optimization rules */
3397 53430 : switch (j->jointype)
3398 : {
3399 9434 : case JOIN_INNER:
3400 :
3401 : /*
3402 : * An inner join is equivalent to a FromExpr, so if either
3403 : * side was simplified to an RTE_RESULT rel, we can replace
3404 : * the join with a FromExpr with just the other side.
3405 : * Furthermore, we can elide that FromExpr according to the
3406 : * same rules as above.
3407 : *
3408 : * Just as in the FromExpr case, we can't simplify if the
3409 : * other input rel references any PHVs that are marked as to
3410 : * be evaluated at the RTE_RESULT rel, because we can't
3411 : * postpone their evaluation in that case. But we only have
3412 : * to check this in cases where it's syntactically legal for
3413 : * the other input to have a LATERAL reference to the
3414 : * RTE_RESULT rel. Only RHSes of inner and left joins are
3415 : * allowed to have such refs.
3416 : */
3417 9434 : if ((varno = get_result_relid(root, j->larg)) != 0 &&
3418 42 : !find_dependent_phvs_in_jointree(root, j->rarg, varno))
3419 : {
3420 42 : remove_result_refs(root, varno, j->rarg);
3421 42 : if (j->quals != NULL && parent_quals == NULL)
3422 12 : jtnode = (Node *)
3423 12 : makeFromExpr(list_make1(j->rarg), j->quals);
3424 : else
3425 : {
3426 : /* Merge any quals up to parent */
3427 30 : if (j->quals != NULL)
3428 12 : *parent_quals = (Node *)
3429 12 : list_concat(castNode(List, j->quals),
3430 : castNode(List, *parent_quals));
3431 30 : jtnode = j->rarg;
3432 : }
3433 : }
3434 9392 : else if ((varno = get_result_relid(root, j->rarg)) != 0)
3435 : {
3436 630 : remove_result_refs(root, varno, j->larg);
3437 630 : if (j->quals != NULL && parent_quals == NULL)
3438 12 : jtnode = (Node *)
3439 12 : makeFromExpr(list_make1(j->larg), j->quals);
3440 : else
3441 : {
3442 : /* Merge any quals up to parent */
3443 618 : if (j->quals != NULL)
3444 568 : *parent_quals = (Node *)
3445 568 : list_concat(castNode(List, j->quals),
3446 : castNode(List, *parent_quals));
3447 618 : jtnode = j->larg;
3448 : }
3449 : }
3450 9434 : break;
3451 41046 : case JOIN_LEFT:
3452 :
3453 : /*
3454 : * We can simplify this case if the RHS is an RTE_RESULT, with
3455 : * two different possibilities:
3456 : *
3457 : * If the qual is empty (JOIN ON TRUE), then the join can be
3458 : * strength-reduced to a plain inner join, since each LHS row
3459 : * necessarily has exactly one join partner. So we can always
3460 : * discard the RHS, much as in the JOIN_INNER case above.
3461 : * (Again, the LHS could not contain a lateral reference to
3462 : * the RHS.)
3463 : *
3464 : * Otherwise, it's still true that each LHS row should be
3465 : * returned exactly once, and since the RHS returns no columns
3466 : * (unless there are PHVs that have to be evaluated there), we
3467 : * don't much care if it's null-extended or not. So in this
3468 : * case also, we can just ignore the qual and discard the left
3469 : * join.
3470 : */
3471 41046 : if ((varno = get_result_relid(root, j->rarg)) != 0 &&
3472 150 : (j->quals == NULL ||
3473 90 : !find_dependent_phvs(root, varno)))
3474 : {
3475 60 : remove_result_refs(root, varno, j->larg);
3476 60 : *dropped_outer_joins = bms_add_member(*dropped_outer_joins,
3477 : j->rtindex);
3478 60 : jtnode = j->larg;
3479 : }
3480 41046 : break;
3481 602 : case JOIN_SEMI:
3482 :
3483 : /*
3484 : * We may simplify this case if the RHS is an RTE_RESULT; the
3485 : * join qual becomes effectively just a filter qual for the
3486 : * LHS, since we should either return the LHS row or not. The
3487 : * filter clause must go into a new FromExpr if we can't push
3488 : * it up to the parent.
3489 : *
3490 : * There is a fine point about PHVs that are supposed to be
3491 : * evaluated at the RHS. Such PHVs could only appear in the
3492 : * semijoin's qual, since the rest of the query cannot
3493 : * reference any outputs of the semijoin's RHS. Therefore,
3494 : * they can't actually go to null before being examined, and
3495 : * it'd be OK to just remove the PHV wrapping. We don't have
3496 : * infrastructure for that, but remove_result_refs() will
3497 : * relabel them as to be evaluated at the LHS, which is fine.
3498 : *
3499 : * Also, we don't need to worry about removing traces of the
3500 : * join's rtindex, since it hasn't got one.
3501 : */
3502 602 : if ((varno = get_result_relid(root, j->rarg)) != 0)
3503 : {
3504 : Assert(j->rtindex == 0);
3505 36 : remove_result_refs(root, varno, j->larg);
3506 36 : if (j->quals != NULL && parent_quals == NULL)
3507 0 : jtnode = (Node *)
3508 0 : makeFromExpr(list_make1(j->larg), j->quals);
3509 : else
3510 : {
3511 : /* Merge any quals up to parent */
3512 36 : if (j->quals != NULL)
3513 36 : *parent_quals = (Node *)
3514 36 : list_concat(castNode(List, j->quals),
3515 : castNode(List, *parent_quals));
3516 36 : jtnode = j->larg;
3517 : }
3518 : }
3519 602 : break;
3520 2348 : case JOIN_FULL:
3521 : case JOIN_ANTI:
3522 : /* We have no special smarts for these cases */
3523 2348 : break;
3524 0 : default:
3525 : /* Note: JOIN_RIGHT should be gone at this point */
3526 0 : elog(ERROR, "unrecognized join type: %d",
3527 : (int) j->jointype);
3528 : break;
3529 : }
3530 : }
3531 : else
3532 0 : elog(ERROR, "unrecognized node type: %d",
3533 : (int) nodeTag(jtnode));
3534 586208 : return jtnode;
3535 : }
3536 :
3537 : /*
3538 : * get_result_relid
3539 : * If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
3540 : * otherwise return 0.
3541 : */
3542 : static int
3543 65456 : get_result_relid(PlannerInfo *root, Node *jtnode)
3544 : {
3545 : int varno;
3546 :
3547 65456 : if (!IsA(jtnode, RangeTblRef))
3548 5188 : return 0;
3549 60268 : varno = ((RangeTblRef *) jtnode)->rtindex;
3550 60268 : if (rt_fetch(varno, root->parse->rtable)->rtekind != RTE_RESULT)
3551 59104 : return 0;
3552 1164 : return varno;
3553 : }
3554 :
3555 : /*
3556 : * remove_result_refs
3557 : * Helper routine for dropping an unneeded RTE_RESULT RTE.
3558 : *
3559 : * This doesn't physically remove the RTE from the jointree, because that's
3560 : * more easily handled in remove_useless_results_recurse. What it does do
3561 : * is the necessary cleanup in the rest of the tree: we must adjust any PHVs
3562 : * that may reference the RTE. Be sure to call this at a point where the
3563 : * jointree is valid (no disconnected nodes).
3564 : *
3565 : * Note that we don't need to process the append_rel_list, since RTEs
3566 : * referenced directly in the jointree won't be appendrel members.
3567 : *
3568 : * varno is the RTE_RESULT's relid.
3569 : * newjtloc is the jointree location at which any PHVs referencing the
3570 : * RTE_RESULT should be evaluated instead.
3571 : */
3572 : static void
3573 1050 : remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc)
3574 : {
3575 : /* Fix up PlaceHolderVars as needed */
3576 : /* If there are no PHVs anywhere, we can skip this bit */
3577 1050 : if (root->glob->lastPHId != 0)
3578 : {
3579 : Relids subrelids;
3580 :
3581 176 : subrelids = get_relids_in_jointree(newjtloc, true, false);
3582 : Assert(!bms_is_empty(subrelids));
3583 176 : substitute_phv_relids((Node *) root->parse, varno, subrelids);
3584 176 : fix_append_rel_relids(root, varno, subrelids);
3585 : }
3586 :
3587 : /*
3588 : * We also need to remove any PlanRowMark referencing the RTE, but we
3589 : * postpone that work until we return to remove_useless_result_rtes.
3590 : */
3591 1050 : }
3592 :
3593 :
3594 : /*
3595 : * find_dependent_phvs - are there any PlaceHolderVars whose relids are
3596 : * exactly the given varno?
3597 : *
3598 : * find_dependent_phvs should be used when we want to see if there are
3599 : * any such PHVs anywhere in the Query. Another use-case is to see if
3600 : * a subtree of the join tree contains such PHVs; but for that, we have
3601 : * to look not only at the join tree nodes themselves but at the
3602 : * referenced RTEs. For that, use find_dependent_phvs_in_jointree.
3603 : */
3604 :
3605 : typedef struct
3606 : {
3607 : Relids relids;
3608 : int sublevels_up;
3609 : } find_dependent_phvs_context;
3610 :
3611 : static bool
3612 2400 : find_dependent_phvs_walker(Node *node,
3613 : find_dependent_phvs_context *context)
3614 : {
3615 2400 : if (node == NULL)
3616 564 : return false;
3617 1836 : if (IsA(node, PlaceHolderVar))
3618 : {
3619 156 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
3620 :
3621 312 : if (phv->phlevelsup == context->sublevels_up &&
3622 156 : bms_equal(context->relids, phv->phrels))
3623 114 : return true;
3624 : /* fall through to examine children */
3625 : }
3626 1722 : if (IsA(node, Query))
3627 : {
3628 : /* Recurse into subselects */
3629 : bool result;
3630 :
3631 48 : context->sublevels_up++;
3632 48 : result = query_tree_walker((Query *) node,
3633 : find_dependent_phvs_walker,
3634 : (void *) context, 0);
3635 48 : context->sublevels_up--;
3636 48 : return result;
3637 : }
3638 : /* Shouldn't need to handle most planner auxiliary nodes here */
3639 : Assert(!IsA(node, SpecialJoinInfo));
3640 : Assert(!IsA(node, PlaceHolderInfo));
3641 : Assert(!IsA(node, MinMaxAggInfo));
3642 :
3643 1674 : return expression_tree_walker(node, find_dependent_phvs_walker,
3644 : (void *) context);
3645 : }
3646 :
3647 : static bool
3648 90 : find_dependent_phvs(PlannerInfo *root, int varno)
3649 : {
3650 : find_dependent_phvs_context context;
3651 :
3652 : /* If there are no PHVs anywhere, we needn't work hard */
3653 90 : if (root->glob->lastPHId == 0)
3654 0 : return false;
3655 :
3656 90 : context.relids = bms_make_singleton(varno);
3657 90 : context.sublevels_up = 0;
3658 :
3659 90 : if (query_tree_walker(root->parse,
3660 : find_dependent_phvs_walker,
3661 : (void *) &context,
3662 : 0))
3663 90 : return true;
3664 : /* The append_rel_list could be populated already, so check it too */
3665 0 : if (expression_tree_walker((Node *) root->append_rel_list,
3666 : find_dependent_phvs_walker,
3667 : (void *) &context))
3668 0 : return true;
3669 0 : return false;
3670 : }
3671 :
3672 : static bool
3673 348 : find_dependent_phvs_in_jointree(PlannerInfo *root, Node *node, int varno)
3674 : {
3675 : find_dependent_phvs_context context;
3676 : Relids subrelids;
3677 : int relid;
3678 :
3679 : /* If there are no PHVs anywhere, we needn't work hard */
3680 348 : if (root->glob->lastPHId == 0)
3681 282 : return false;
3682 :
3683 66 : context.relids = bms_make_singleton(varno);
3684 66 : context.sublevels_up = 0;
3685 :
3686 : /*
3687 : * See if the jointree fragment itself contains references (in join quals)
3688 : */
3689 66 : if (find_dependent_phvs_walker(node, &context))
3690 0 : return true;
3691 :
3692 : /*
3693 : * Otherwise, identify the set of referenced RTEs (we can ignore joins,
3694 : * since they should be flattened already, so their join alias lists no
3695 : * longer matter), and tediously check each RTE. We can ignore RTEs that
3696 : * are not marked LATERAL, though, since they couldn't possibly contain
3697 : * any cross-references to other RTEs.
3698 : */
3699 66 : subrelids = get_relids_in_jointree(node, false, false);
3700 66 : relid = -1;
3701 144 : while ((relid = bms_next_member(subrelids, relid)) >= 0)
3702 : {
3703 102 : RangeTblEntry *rte = rt_fetch(relid, root->parse->rtable);
3704 :
3705 126 : if (rte->lateral &&
3706 24 : range_table_entry_walker(rte,
3707 : find_dependent_phvs_walker,
3708 : (void *) &context,
3709 : 0))
3710 24 : return true;
3711 : }
3712 :
3713 42 : return false;
3714 : }
3715 :
3716 : /*
3717 : * substitute_phv_relids - adjust PlaceHolderVar relid sets after pulling up
3718 : * a subquery or removing an RTE_RESULT jointree item
3719 : *
3720 : * Find any PlaceHolderVar nodes in the given tree that reference the
3721 : * pulled-up relid, and change them to reference the replacement relid(s).
3722 : *
3723 : * NOTE: although this has the form of a walker, we cheat and modify the
3724 : * nodes in-place. This should be OK since the tree was copied by
3725 : * pullup_replace_vars earlier. Avoid scribbling on the original values of
3726 : * the bitmapsets, though, because expression_tree_mutator doesn't copy those.
3727 : */
3728 :
3729 : typedef struct
3730 : {
3731 : int varno;
3732 : int sublevels_up;
3733 : Relids subrelids;
3734 : } substitute_phv_relids_context;
3735 :
3736 : static bool
3737 187100 : substitute_phv_relids_walker(Node *node,
3738 : substitute_phv_relids_context *context)
3739 : {
3740 187100 : if (node == NULL)
3741 72312 : return false;
3742 114788 : if (IsA(node, PlaceHolderVar))
3743 : {
3744 5460 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
3745 :
3746 10888 : if (phv->phlevelsup == context->sublevels_up &&
3747 5428 : bms_is_member(context->varno, phv->phrels))
3748 : {
3749 7368 : phv->phrels = bms_union(phv->phrels,
3750 3684 : context->subrelids);
3751 3684 : phv->phrels = bms_del_member(phv->phrels,
3752 : context->varno);
3753 : /* Assert we haven't broken the PHV */
3754 : Assert(!bms_is_empty(phv->phrels));
3755 : }
3756 : /* fall through to examine children */
3757 : }
3758 114788 : if (IsA(node, Query))
3759 : {
3760 : /* Recurse into subselects */
3761 : bool result;
3762 :
3763 3008 : context->sublevels_up++;
3764 3008 : result = query_tree_walker((Query *) node,
3765 : substitute_phv_relids_walker,
3766 : (void *) context, 0);
3767 3008 : context->sublevels_up--;
3768 3008 : return result;
3769 : }
3770 : /* Shouldn't need to handle planner auxiliary nodes here */
3771 : Assert(!IsA(node, SpecialJoinInfo));
3772 : Assert(!IsA(node, AppendRelInfo));
3773 : Assert(!IsA(node, PlaceHolderInfo));
3774 : Assert(!IsA(node, MinMaxAggInfo));
3775 :
3776 111780 : return expression_tree_walker(node, substitute_phv_relids_walker,
3777 : (void *) context);
3778 : }
3779 :
3780 : static void
3781 1772 : substitute_phv_relids(Node *node, int varno, Relids subrelids)
3782 : {
3783 : substitute_phv_relids_context context;
3784 :
3785 1772 : context.varno = varno;
3786 1772 : context.sublevels_up = 0;
3787 1772 : context.subrelids = subrelids;
3788 :
3789 : /*
3790 : * Must be prepared to start with a Query or a bare expression tree.
3791 : */
3792 1772 : query_or_expression_tree_walker(node,
3793 : substitute_phv_relids_walker,
3794 : (void *) &context,
3795 : 0);
3796 1772 : }
3797 :
3798 : /*
3799 : * fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
3800 : *
3801 : * When we pull up a subquery, any AppendRelInfo references to the subquery's
3802 : * RT index have to be replaced by the substituted relid (and there had better
3803 : * be only one). We also need to apply substitute_phv_relids to their
3804 : * translated_vars lists, since those might contain PlaceHolderVars.
3805 : *
3806 : * We assume we may modify the AppendRelInfo nodes in-place.
3807 : */
3808 : static void
3809 4520 : fix_append_rel_relids(PlannerInfo *root, int varno, Relids subrelids)
3810 : {
3811 : ListCell *l;
3812 4520 : int subvarno = -1;
3813 :
3814 : /*
3815 : * We only want to extract the member relid once, but we mustn't fail
3816 : * immediately if there are multiple members; it could be that none of the
3817 : * AppendRelInfo nodes refer to it. So compute it on first use. Note that
3818 : * bms_singleton_member will complain if set is not singleton.
3819 : */
3820 9752 : foreach(l, root->append_rel_list)
3821 : {
3822 5232 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
3823 :
3824 : /* The parent_relid shouldn't ever be a pullup target */
3825 : Assert(appinfo->parent_relid != varno);
3826 :
3827 5232 : if (appinfo->child_relid == varno)
3828 : {
3829 2916 : if (subvarno < 0)
3830 2916 : subvarno = bms_singleton_member(subrelids);
3831 2916 : appinfo->child_relid = subvarno;
3832 : }
3833 :
3834 : /* Also fix up any PHVs in its translated vars */
3835 5232 : if (root->glob->lastPHId != 0)
3836 114 : substitute_phv_relids((Node *) appinfo->translated_vars,
3837 : varno, subrelids);
3838 : }
3839 4520 : }
3840 :
3841 : /*
3842 : * get_relids_in_jointree: get set of RT indexes present in a jointree
3843 : *
3844 : * Base-relation relids are always included in the result.
3845 : * If include_outer_joins is true, outer-join RT indexes are included.
3846 : * If include_inner_joins is true, inner-join RT indexes are included.
3847 : *
3848 : * Note that for most purposes in the planner, outer joins are included
3849 : * in standard relid sets. Setting include_inner_joins true is only
3850 : * appropriate for special purposes during subquery flattening.
3851 : */
3852 : Relids
3853 77064 : get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
3854 : bool include_inner_joins)
3855 : {
3856 77064 : Relids result = NULL;
3857 :
3858 77064 : if (jtnode == NULL)
3859 0 : return result;
3860 77064 : if (IsA(jtnode, RangeTblRef))
3861 : {
3862 38492 : int varno = ((RangeTblRef *) jtnode)->rtindex;
3863 :
3864 38492 : result = bms_make_singleton(varno);
3865 : }
3866 38572 : else if (IsA(jtnode, FromExpr))
3867 : {
3868 34320 : FromExpr *f = (FromExpr *) jtnode;
3869 : ListCell *l;
3870 :
3871 69658 : foreach(l, f->fromlist)
3872 : {
3873 35338 : result = bms_join(result,
3874 35338 : get_relids_in_jointree(lfirst(l),
3875 : include_outer_joins,
3876 : include_inner_joins));
3877 : }
3878 : }
3879 4252 : else if (IsA(jtnode, JoinExpr))
3880 : {
3881 4252 : JoinExpr *j = (JoinExpr *) jtnode;
3882 :
3883 4252 : result = get_relids_in_jointree(j->larg,
3884 : include_outer_joins,
3885 : include_inner_joins);
3886 4252 : result = bms_join(result,
3887 : get_relids_in_jointree(j->rarg,
3888 : include_outer_joins,
3889 : include_inner_joins));
3890 4252 : if (j->rtindex)
3891 : {
3892 3974 : if (j->jointype == JOIN_INNER)
3893 : {
3894 1536 : if (include_inner_joins)
3895 168 : result = bms_add_member(result, j->rtindex);
3896 : }
3897 : else
3898 : {
3899 2438 : if (include_outer_joins)
3900 1398 : result = bms_add_member(result, j->rtindex);
3901 : }
3902 : }
3903 : }
3904 : else
3905 0 : elog(ERROR, "unrecognized node type: %d",
3906 : (int) nodeTag(jtnode));
3907 77064 : return result;
3908 : }
3909 :
3910 : /*
3911 : * get_relids_for_join: get set of base+OJ RT indexes making up a join
3912 : */
3913 : Relids
3914 334 : get_relids_for_join(Query *query, int joinrelid)
3915 : {
3916 : Node *jtnode;
3917 :
3918 334 : jtnode = find_jointree_node_for_rel((Node *) query->jointree,
3919 : joinrelid);
3920 334 : if (!jtnode)
3921 0 : elog(ERROR, "could not find join node %d", joinrelid);
3922 334 : return get_relids_in_jointree(jtnode, true, false);
3923 : }
3924 :
3925 : /*
3926 : * find_jointree_node_for_rel: locate jointree node for a base or join RT index
3927 : *
3928 : * Returns NULL if not found
3929 : */
3930 : static Node *
3931 1640 : find_jointree_node_for_rel(Node *jtnode, int relid)
3932 : {
3933 1640 : if (jtnode == NULL)
3934 0 : return NULL;
3935 1640 : if (IsA(jtnode, RangeTblRef))
3936 : {
3937 436 : int varno = ((RangeTblRef *) jtnode)->rtindex;
3938 :
3939 436 : if (relid == varno)
3940 0 : return jtnode;
3941 : }
3942 1204 : else if (IsA(jtnode, FromExpr))
3943 : {
3944 350 : FromExpr *f = (FromExpr *) jtnode;
3945 : ListCell *l;
3946 :
3947 386 : foreach(l, f->fromlist)
3948 : {
3949 386 : jtnode = find_jointree_node_for_rel(lfirst(l), relid);
3950 386 : if (jtnode)
3951 350 : return jtnode;
3952 : }
3953 : }
3954 854 : else if (IsA(jtnode, JoinExpr))
3955 : {
3956 854 : JoinExpr *j = (JoinExpr *) jtnode;
3957 :
3958 854 : if (relid == j->rtindex)
3959 334 : return jtnode;
3960 520 : jtnode = find_jointree_node_for_rel(j->larg, relid);
3961 520 : if (jtnode)
3962 120 : return jtnode;
3963 400 : jtnode = find_jointree_node_for_rel(j->rarg, relid);
3964 400 : if (jtnode)
3965 400 : return jtnode;
3966 : }
3967 : else
3968 0 : elog(ERROR, "unrecognized node type: %d",
3969 : (int) nodeTag(jtnode));
3970 436 : return NULL;
3971 : }
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