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 : * expand_virtual_generated_columns
11 : * pull_up_subqueries
12 : * flatten_simple_union_all
13 : * do expression preprocessing (including flattening JOIN alias vars)
14 : * reduce_outer_joins
15 : * remove_useless_result_rtes
16 : *
17 : *
18 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
19 : * Portions Copyright (c) 1994, Regents of the University of California
20 : *
21 : *
22 : * IDENTIFICATION
23 : * src/backend/optimizer/prep/prepjointree.c
24 : *
25 : *-------------------------------------------------------------------------
26 : */
27 : #include "postgres.h"
28 :
29 : #include "access/table.h"
30 : #include "catalog/pg_type.h"
31 : #include "funcapi.h"
32 : #include "miscadmin.h"
33 : #include "nodes/makefuncs.h"
34 : #include "nodes/multibitmapset.h"
35 : #include "nodes/nodeFuncs.h"
36 : #include "optimizer/clauses.h"
37 : #include "optimizer/optimizer.h"
38 : #include "optimizer/placeholder.h"
39 : #include "optimizer/prep.h"
40 : #include "optimizer/subselect.h"
41 : #include "optimizer/tlist.h"
42 : #include "parser/parse_relation.h"
43 : #include "parser/parsetree.h"
44 : #include "rewrite/rewriteHandler.h"
45 : #include "rewrite/rewriteManip.h"
46 : #include "utils/rel.h"
47 :
48 :
49 : typedef struct nullingrel_info
50 : {
51 : /*
52 : * For each leaf RTE, nullingrels[rti] is the set of relids of outer joins
53 : * that potentially null that RTE.
54 : */
55 : Relids *nullingrels;
56 : /* Length of range table (maximum index in nullingrels[]) */
57 : int rtlength; /* used only for assertion checks */
58 : } nullingrel_info;
59 :
60 : /* Options for wrapping an expression for identification purposes */
61 : typedef enum ReplaceWrapOption
62 : {
63 : REPLACE_WRAP_NONE, /* no expressions need to be wrapped */
64 : REPLACE_WRAP_ALL, /* all expressions need to be wrapped */
65 : REPLACE_WRAP_VARFREE, /* variable-free expressions need to be
66 : * wrapped */
67 : } ReplaceWrapOption;
68 :
69 : typedef struct pullup_replace_vars_context
70 : {
71 : PlannerInfo *root;
72 : List *targetlist; /* tlist of subquery being pulled up */
73 : RangeTblEntry *target_rte; /* RTE of subquery */
74 : int result_relation; /* the index of the result relation in the
75 : * rewritten query */
76 : Relids relids; /* relids within subquery, as numbered after
77 : * pullup (set only if target_rte->lateral) */
78 : nullingrel_info *nullinfo; /* per-RTE nullingrel info (set only if
79 : * target_rte->lateral) */
80 : bool *outer_hasSubLinks; /* -> outer query's hasSubLinks */
81 : int varno; /* varno of subquery */
82 : ReplaceWrapOption wrap_option; /* do we need certain outputs to be PHVs? */
83 : Node **rv_cache; /* cache for results with PHVs */
84 : } pullup_replace_vars_context;
85 :
86 : typedef struct reduce_outer_joins_pass1_state
87 : {
88 : Relids relids; /* base relids within this subtree */
89 : bool contains_outer; /* does subtree contain outer join(s)? */
90 : List *sub_states; /* List of states for subtree components */
91 : } reduce_outer_joins_pass1_state;
92 :
93 : typedef struct reduce_outer_joins_pass2_state
94 : {
95 : Relids inner_reduced; /* OJ relids reduced to plain inner joins */
96 : List *partial_reduced; /* List of partially reduced FULL joins */
97 : } reduce_outer_joins_pass2_state;
98 :
99 : typedef struct reduce_outer_joins_partial_state
100 : {
101 : int full_join_rti; /* RT index of a formerly-FULL join */
102 : Relids unreduced_side; /* relids in its still-nullable side */
103 : } reduce_outer_joins_partial_state;
104 :
105 : static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
106 : Relids *relids);
107 : static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
108 : Node **jtlink1, Relids available_rels1,
109 : Node **jtlink2, Relids available_rels2);
110 : static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
111 : JoinExpr *lowest_outer_join,
112 : AppendRelInfo *containing_appendrel);
113 : static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
114 : RangeTblEntry *rte,
115 : JoinExpr *lowest_outer_join,
116 : AppendRelInfo *containing_appendrel);
117 : static Node *pull_up_simple_union_all(PlannerInfo *root, Node *jtnode,
118 : RangeTblEntry *rte);
119 : static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
120 : int parentRTindex, Query *setOpQuery,
121 : int childRToffset);
122 : static void make_setop_translation_list(Query *query, int newvarno,
123 : AppendRelInfo *appinfo);
124 : static bool is_simple_subquery(PlannerInfo *root, Query *subquery,
125 : RangeTblEntry *rte,
126 : JoinExpr *lowest_outer_join);
127 : static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
128 : RangeTblEntry *rte);
129 : static bool is_simple_values(PlannerInfo *root, RangeTblEntry *rte);
130 : static Node *pull_up_constant_function(PlannerInfo *root, Node *jtnode,
131 : RangeTblEntry *rte,
132 : AppendRelInfo *containing_appendrel);
133 : static bool is_simple_union_all(Query *subquery);
134 : static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery,
135 : List *colTypes);
136 : static bool is_safe_append_member(Query *subquery);
137 : static bool jointree_contains_lateral_outer_refs(PlannerInfo *root,
138 : Node *jtnode, bool restricted,
139 : Relids safe_upper_varnos);
140 : static void perform_pullup_replace_vars(PlannerInfo *root,
141 : pullup_replace_vars_context *rvcontext,
142 : AppendRelInfo *containing_appendrel);
143 : static void replace_vars_in_jointree(Node *jtnode,
144 : pullup_replace_vars_context *context);
145 : static Node *pullup_replace_vars(Node *expr,
146 : pullup_replace_vars_context *context);
147 : static Node *pullup_replace_vars_callback(Var *var,
148 : replace_rte_variables_context *context);
149 : static Query *pullup_replace_vars_subquery(Query *query,
150 : pullup_replace_vars_context *context);
151 : static reduce_outer_joins_pass1_state *reduce_outer_joins_pass1(Node *jtnode);
152 : static void reduce_outer_joins_pass2(Node *jtnode,
153 : reduce_outer_joins_pass1_state *state1,
154 : reduce_outer_joins_pass2_state *state2,
155 : PlannerInfo *root,
156 : Relids nonnullable_rels,
157 : List *forced_null_vars);
158 : static void report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
159 : int rtindex, Relids relids);
160 : static Node *remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
161 : Node **parent_quals,
162 : Relids *dropped_outer_joins);
163 : static int get_result_relid(PlannerInfo *root, Node *jtnode);
164 : static void remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc);
165 : static bool find_dependent_phvs(PlannerInfo *root, int varno);
166 : static bool find_dependent_phvs_in_jointree(PlannerInfo *root,
167 : Node *node, int varno);
168 : static void substitute_phv_relids(Node *node,
169 : int varno, Relids subrelids);
170 : static void fix_append_rel_relids(PlannerInfo *root, int varno,
171 : Relids subrelids);
172 : static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
173 : static nullingrel_info *get_nullingrels(Query *parse);
174 : static void get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
175 : nullingrel_info *info);
176 :
177 :
178 : /*
179 : * transform_MERGE_to_join
180 : * Replace a MERGE's jointree to also include the target relation.
181 : */
182 : void
183 534390 : transform_MERGE_to_join(Query *parse)
184 : {
185 : RangeTblEntry *joinrte;
186 : JoinExpr *joinexpr;
187 : bool have_action[NUM_MERGE_MATCH_KINDS];
188 : JoinType jointype;
189 : int joinrti;
190 : List *vars;
191 : RangeTblRef *rtr;
192 : FromExpr *target;
193 : Node *source;
194 : int sourcerti;
195 :
196 534390 : if (parse->commandType != CMD_MERGE)
197 532548 : return;
198 :
199 : /* XXX probably bogus */
200 1842 : vars = NIL;
201 :
202 : /*
203 : * Work out what kind of join is required. If there any WHEN NOT MATCHED
204 : * BY SOURCE/TARGET actions, an outer join is required so that we process
205 : * all unmatched tuples from the source and/or target relations.
206 : * Otherwise, we can use an inner join.
207 : */
208 1842 : have_action[MERGE_WHEN_MATCHED] = false;
209 1842 : have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = false;
210 1842 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = false;
211 :
212 6498 : foreach_node(MergeAction, action, parse->mergeActionList)
213 : {
214 2814 : if (action->commandType != CMD_NOTHING)
215 2742 : have_action[action->matchKind] = true;
216 : }
217 :
218 1842 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] &&
219 126 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
220 96 : jointype = JOIN_FULL;
221 1746 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
222 30 : jointype = JOIN_LEFT;
223 1716 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
224 794 : jointype = JOIN_RIGHT;
225 : else
226 922 : jointype = JOIN_INNER;
227 :
228 : /* Manufacture a join RTE to use. */
229 1842 : joinrte = makeNode(RangeTblEntry);
230 1842 : joinrte->rtekind = RTE_JOIN;
231 1842 : joinrte->jointype = jointype;
232 1842 : joinrte->joinmergedcols = 0;
233 1842 : joinrte->joinaliasvars = vars;
234 1842 : joinrte->joinleftcols = NIL; /* MERGE does not allow JOIN USING */
235 1842 : joinrte->joinrightcols = NIL; /* ditto */
236 1842 : joinrte->join_using_alias = NULL;
237 :
238 1842 : joinrte->alias = NULL;
239 1842 : joinrte->eref = makeAlias("*MERGE*", NIL);
240 1842 : joinrte->lateral = false;
241 1842 : joinrte->inh = false;
242 1842 : joinrte->inFromCl = true;
243 :
244 : /*
245 : * Add completed RTE to pstate's range table list, so that we know its
246 : * index.
247 : */
248 1842 : parse->rtable = lappend(parse->rtable, joinrte);
249 1842 : joinrti = list_length(parse->rtable);
250 :
251 : /*
252 : * Create a JOIN between the target and the source relation.
253 : *
254 : * Here the target is identified by parse->mergeTargetRelation. For a
255 : * regular table, this will equal parse->resultRelation, but for a
256 : * trigger-updatable view, it will be the expanded view subquery that we
257 : * need to pull data from.
258 : *
259 : * The source relation is in parse->jointree->fromlist, but any quals in
260 : * parse->jointree->quals are restrictions on the target relation (if the
261 : * target relation is an auto-updatable view).
262 : */
263 : /* target rel, with any quals */
264 1842 : rtr = makeNode(RangeTblRef);
265 1842 : rtr->rtindex = parse->mergeTargetRelation;
266 1842 : target = makeFromExpr(list_make1(rtr), parse->jointree->quals);
267 :
268 : /* source rel (expect exactly one -- see transformMergeStmt()) */
269 : Assert(list_length(parse->jointree->fromlist) == 1);
270 1842 : source = linitial(parse->jointree->fromlist);
271 :
272 : /*
273 : * index of source rel (expect either a RangeTblRef or a JoinExpr -- see
274 : * transformFromClauseItem()).
275 : */
276 1842 : if (IsA(source, RangeTblRef))
277 1758 : sourcerti = ((RangeTblRef *) source)->rtindex;
278 84 : else if (IsA(source, JoinExpr))
279 84 : sourcerti = ((JoinExpr *) source)->rtindex;
280 : else
281 : {
282 0 : elog(ERROR, "unrecognized source node type: %d",
283 : (int) nodeTag(source));
284 : sourcerti = 0; /* keep compiler quiet */
285 : }
286 :
287 : /* Join the source and target */
288 1842 : joinexpr = makeNode(JoinExpr);
289 1842 : joinexpr->jointype = jointype;
290 1842 : joinexpr->isNatural = false;
291 1842 : joinexpr->larg = (Node *) target;
292 1842 : joinexpr->rarg = source;
293 1842 : joinexpr->usingClause = NIL;
294 1842 : joinexpr->join_using_alias = NULL;
295 1842 : joinexpr->quals = parse->mergeJoinCondition;
296 1842 : joinexpr->alias = NULL;
297 1842 : joinexpr->rtindex = joinrti;
298 :
299 : /* Make the new join be the sole entry in the query's jointree */
300 1842 : parse->jointree->fromlist = list_make1(joinexpr);
301 1842 : parse->jointree->quals = NULL;
302 :
303 : /*
304 : * If necessary, mark parse->targetlist entries that refer to the target
305 : * as nullable by the join. Normally the targetlist will be empty for a
306 : * MERGE, but if the target is a trigger-updatable view, it will contain a
307 : * whole-row Var referring to the expanded view query.
308 : */
309 1842 : if (parse->targetList != NIL &&
310 42 : (jointype == JOIN_RIGHT || jointype == JOIN_FULL))
311 42 : parse->targetList = (List *)
312 42 : add_nulling_relids((Node *) parse->targetList,
313 42 : bms_make_singleton(parse->mergeTargetRelation),
314 42 : bms_make_singleton(joinrti));
315 :
316 : /*
317 : * If the source relation is on the outer side of the join, mark any
318 : * source relation Vars in the join condition, actions, and RETURNING list
319 : * as nullable by the join. These Vars will be added to the targetlist by
320 : * preprocess_targetlist(), so it's important to mark them correctly here.
321 : *
322 : * It might seem that this is not necessary for Vars in the join
323 : * condition, since it is inside the join, but it is also needed above the
324 : * join (in the ModifyTable node) to distinguish between the MATCHED and
325 : * NOT MATCHED BY SOURCE cases -- see ExecMergeMatched(). Note that this
326 : * creates a modified copy of the join condition, for use above the join,
327 : * without modifying the original join condition, inside the join.
328 : */
329 1842 : if (jointype == JOIN_LEFT || jointype == JOIN_FULL)
330 : {
331 126 : parse->mergeJoinCondition =
332 126 : add_nulling_relids(parse->mergeJoinCondition,
333 126 : bms_make_singleton(sourcerti),
334 126 : bms_make_singleton(joinrti));
335 :
336 600 : foreach_node(MergeAction, action, parse->mergeActionList)
337 : {
338 348 : action->qual =
339 348 : add_nulling_relids(action->qual,
340 348 : bms_make_singleton(sourcerti),
341 348 : bms_make_singleton(joinrti));
342 :
343 348 : action->targetList = (List *)
344 348 : add_nulling_relids((Node *) action->targetList,
345 348 : bms_make_singleton(sourcerti),
346 348 : bms_make_singleton(joinrti));
347 : }
348 :
349 126 : parse->returningList = (List *)
350 126 : add_nulling_relids((Node *) parse->returningList,
351 126 : bms_make_singleton(sourcerti),
352 126 : bms_make_singleton(joinrti));
353 : }
354 :
355 : /*
356 : * If there are any WHEN NOT MATCHED BY SOURCE actions, the executor will
357 : * use the join condition to distinguish between MATCHED and NOT MATCHED
358 : * BY SOURCE cases. Otherwise, it's no longer needed, and we set it to
359 : * NULL, saving cycles during planning and execution.
360 : *
361 : * We need to be careful though: the executor evaluates this condition
362 : * using the output of the join subplan node, which nulls the output from
363 : * the source relation when the join condition doesn't match. That risks
364 : * producing incorrect results when rechecking using a "non-strict" join
365 : * condition, such as "src.col IS NOT DISTINCT FROM tgt.col". To guard
366 : * against that, we add an additional "src IS NOT NULL" check to the join
367 : * condition, so that it does the right thing when performing a recheck
368 : * based on the output of the join subplan.
369 : */
370 1842 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
371 : {
372 : Var *var;
373 : NullTest *ntest;
374 :
375 : /* source wholerow Var (nullable by the new join) */
376 126 : var = makeWholeRowVar(rt_fetch(sourcerti, parse->rtable),
377 : sourcerti, 0, false);
378 126 : var->varnullingrels = bms_make_singleton(joinrti);
379 :
380 : /* "src IS NOT NULL" check */
381 126 : ntest = makeNode(NullTest);
382 126 : ntest->arg = (Expr *) var;
383 126 : ntest->nulltesttype = IS_NOT_NULL;
384 126 : ntest->argisrow = false;
385 126 : ntest->location = -1;
386 :
387 : /* combine it with the original join condition */
388 126 : parse->mergeJoinCondition =
389 126 : (Node *) make_and_qual((Node *) ntest, parse->mergeJoinCondition);
390 : }
391 : else
392 1716 : parse->mergeJoinCondition = NULL; /* join condition not needed */
393 : }
394 :
395 : /*
396 : * replace_empty_jointree
397 : * If the Query's jointree is empty, replace it with a dummy RTE_RESULT
398 : * relation.
399 : *
400 : * By doing this, we can avoid a bunch of corner cases that formerly existed
401 : * for SELECTs with omitted FROM clauses. An example is that a subquery
402 : * with empty jointree previously could not be pulled up, because that would
403 : * have resulted in an empty relid set, making the subquery not uniquely
404 : * identifiable for join or PlaceHolderVar processing.
405 : *
406 : * Unlike most other functions in this file, this function doesn't recurse;
407 : * we rely on other processing to invoke it on sub-queries at suitable times.
408 : */
409 : void
410 574688 : replace_empty_jointree(Query *parse)
411 : {
412 : RangeTblEntry *rte;
413 : Index rti;
414 : RangeTblRef *rtr;
415 :
416 : /* Nothing to do if jointree is already nonempty */
417 574688 : if (parse->jointree->fromlist != NIL)
418 373676 : return;
419 :
420 : /* We mustn't change it in the top level of a setop tree, either */
421 207614 : if (parse->setOperations)
422 6602 : return;
423 :
424 : /* Create suitable RTE */
425 201012 : rte = makeNode(RangeTblEntry);
426 201012 : rte->rtekind = RTE_RESULT;
427 201012 : rte->eref = makeAlias("*RESULT*", NIL);
428 :
429 : /* Add it to rangetable */
430 201012 : parse->rtable = lappend(parse->rtable, rte);
431 201012 : rti = list_length(parse->rtable);
432 :
433 : /* And jam a reference into the jointree */
434 201012 : rtr = makeNode(RangeTblRef);
435 201012 : rtr->rtindex = rti;
436 201012 : parse->jointree->fromlist = list_make1(rtr);
437 : }
438 :
439 : /*
440 : * pull_up_sublinks
441 : * Attempt to pull up ANY and EXISTS SubLinks to be treated as
442 : * semijoins or anti-semijoins.
443 : *
444 : * A clause "foo op ANY (sub-SELECT)" can be processed by pulling the
445 : * sub-SELECT up to become a rangetable entry and treating the implied
446 : * comparisons as quals of a semijoin. However, this optimization *only*
447 : * works at the top level of WHERE or a JOIN/ON clause, because we cannot
448 : * distinguish whether the ANY ought to return FALSE or NULL in cases
449 : * involving NULL inputs. Also, in an outer join's ON clause we can only
450 : * do this if the sublink is degenerate (ie, references only the nullable
451 : * side of the join). In that case it is legal to push the semijoin
452 : * down into the nullable side of the join. If the sublink references any
453 : * nonnullable-side variables then it would have to be evaluated as part
454 : * of the outer join, which makes things way too complicated.
455 : *
456 : * Under similar conditions, EXISTS and NOT EXISTS clauses can be handled
457 : * by pulling up the sub-SELECT and creating a semijoin or anti-semijoin.
458 : *
459 : * This routine searches for such clauses and does the necessary parsetree
460 : * transformations if any are found.
461 : *
462 : * This routine has to run before preprocess_expression(), so the quals
463 : * clauses are not yet reduced to implicit-AND format, and are not guaranteed
464 : * to be AND/OR-flat either. That means we need to recursively search through
465 : * explicit AND clauses. We stop as soon as we hit a non-AND item.
466 : */
467 : void
468 40122 : pull_up_sublinks(PlannerInfo *root)
469 : {
470 : Node *jtnode;
471 : Relids relids;
472 :
473 : /* Begin recursion through the jointree */
474 40122 : jtnode = pull_up_sublinks_jointree_recurse(root,
475 40122 : (Node *) root->parse->jointree,
476 : &relids);
477 :
478 : /*
479 : * root->parse->jointree must always be a FromExpr, so insert a dummy one
480 : * if we got a bare RangeTblRef or JoinExpr out of the recursion.
481 : */
482 40122 : if (IsA(jtnode, FromExpr))
483 32384 : root->parse->jointree = (FromExpr *) jtnode;
484 : else
485 7738 : root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
486 40122 : }
487 :
488 : /*
489 : * Recurse through jointree nodes for pull_up_sublinks()
490 : *
491 : * In addition to returning the possibly-modified jointree node, we return
492 : * a relids set of the contained rels into *relids.
493 : */
494 : static Node *
495 134622 : pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
496 : Relids *relids)
497 : {
498 : /* Since this function recurses, it could be driven to stack overflow. */
499 134622 : check_stack_depth();
500 :
501 134622 : if (jtnode == NULL)
502 : {
503 0 : *relids = NULL;
504 : }
505 134622 : else if (IsA(jtnode, RangeTblRef))
506 : {
507 72916 : int varno = ((RangeTblRef *) jtnode)->rtindex;
508 :
509 72916 : *relids = bms_make_singleton(varno);
510 : /* jtnode is returned unmodified */
511 : }
512 61706 : else if (IsA(jtnode, FromExpr))
513 : {
514 40350 : FromExpr *f = (FromExpr *) jtnode;
515 40350 : List *newfromlist = NIL;
516 40350 : Relids frelids = NULL;
517 : FromExpr *newf;
518 : Node *jtlink;
519 : ListCell *l;
520 :
521 : /* First, recurse to process children and collect their relids */
522 84180 : foreach(l, f->fromlist)
523 : {
524 : Node *newchild;
525 : Relids childrelids;
526 :
527 43830 : newchild = pull_up_sublinks_jointree_recurse(root,
528 43830 : lfirst(l),
529 : &childrelids);
530 43830 : newfromlist = lappend(newfromlist, newchild);
531 43830 : frelids = bms_join(frelids, childrelids);
532 : }
533 : /* Build the replacement FromExpr; no quals yet */
534 40350 : newf = makeFromExpr(newfromlist, NULL);
535 : /* Set up a link representing the rebuilt jointree */
536 40350 : jtlink = (Node *) newf;
537 : /* Now process qual --- all children are available for use */
538 40350 : newf->quals = pull_up_sublinks_qual_recurse(root, f->quals,
539 : &jtlink, frelids,
540 : NULL, NULL);
541 :
542 : /*
543 : * Note that the result will be either newf, or a stack of JoinExprs
544 : * with newf at the base. We rely on subsequent optimization steps to
545 : * flatten this and rearrange the joins as needed.
546 : *
547 : * Although we could include the pulled-up subqueries in the returned
548 : * relids, there's no need since upper quals couldn't refer to their
549 : * outputs anyway.
550 : */
551 40350 : *relids = frelids;
552 40350 : jtnode = jtlink;
553 : }
554 21356 : else if (IsA(jtnode, JoinExpr))
555 : {
556 : JoinExpr *j;
557 : Relids leftrelids;
558 : Relids rightrelids;
559 : Node *jtlink;
560 :
561 : /*
562 : * Make a modifiable copy of join node, but don't bother copying its
563 : * subnodes (yet).
564 : */
565 21356 : j = (JoinExpr *) palloc(sizeof(JoinExpr));
566 21356 : memcpy(j, jtnode, sizeof(JoinExpr));
567 21356 : jtlink = (Node *) j;
568 :
569 : /* Recurse to process children and collect their relids */
570 21356 : j->larg = pull_up_sublinks_jointree_recurse(root, j->larg,
571 : &leftrelids);
572 21356 : j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg,
573 : &rightrelids);
574 :
575 : /*
576 : * Now process qual, showing appropriate child relids as available,
577 : * and attach any pulled-up jointree items at the right place. In the
578 : * inner-join case we put new JoinExprs above the existing one (much
579 : * as for a FromExpr-style join). In outer-join cases the new
580 : * JoinExprs must go into the nullable side of the outer join. The
581 : * point of the available_rels machinations is to ensure that we only
582 : * pull up quals for which that's okay.
583 : *
584 : * We don't expect to see any pre-existing JOIN_SEMI, JOIN_ANTI,
585 : * JOIN_RIGHT_SEMI, or JOIN_RIGHT_ANTI jointypes here.
586 : */
587 21356 : switch (j->jointype)
588 : {
589 9604 : case JOIN_INNER:
590 9604 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
591 : &jtlink,
592 : bms_union(leftrelids,
593 : rightrelids),
594 : NULL, NULL);
595 9604 : break;
596 11644 : case JOIN_LEFT:
597 11644 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
598 : &j->rarg,
599 : rightrelids,
600 : NULL, NULL);
601 11644 : break;
602 12 : case JOIN_FULL:
603 : /* can't do anything with full-join quals */
604 12 : break;
605 96 : case JOIN_RIGHT:
606 96 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
607 : &j->larg,
608 : leftrelids,
609 : NULL, NULL);
610 96 : break;
611 0 : default:
612 0 : elog(ERROR, "unrecognized join type: %d",
613 : (int) j->jointype);
614 : break;
615 : }
616 :
617 : /*
618 : * Although we could include the pulled-up subqueries in the returned
619 : * relids, there's no need since upper quals couldn't refer to their
620 : * outputs anyway. But we *do* need to include the join's own rtindex
621 : * because we haven't yet collapsed join alias variables, so upper
622 : * levels would mistakenly think they couldn't use references to this
623 : * join.
624 : */
625 21356 : *relids = bms_join(leftrelids, rightrelids);
626 21356 : if (j->rtindex)
627 21356 : *relids = bms_add_member(*relids, j->rtindex);
628 21356 : jtnode = jtlink;
629 : }
630 : else
631 0 : elog(ERROR, "unrecognized node type: %d",
632 : (int) nodeTag(jtnode));
633 134622 : return jtnode;
634 : }
635 :
636 : /*
637 : * Recurse through top-level qual nodes for pull_up_sublinks()
638 : *
639 : * jtlink1 points to the link in the jointree where any new JoinExprs should
640 : * be inserted if they reference available_rels1 (i.e., available_rels1
641 : * denotes the relations present underneath jtlink1). Optionally, jtlink2 can
642 : * point to a second link where new JoinExprs should be inserted if they
643 : * reference available_rels2 (pass NULL for both those arguments if not used).
644 : * Note that SubLinks referencing both sets of variables cannot be optimized.
645 : * If we find multiple pull-up-able SubLinks, they'll get stacked onto jtlink1
646 : * and/or jtlink2 in the order we encounter them. We rely on subsequent
647 : * optimization to rearrange the stack if appropriate.
648 : *
649 : * Returns the replacement qual node, or NULL if the qual should be removed.
650 : */
651 : static Node *
652 126468 : pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
653 : Node **jtlink1, Relids available_rels1,
654 : Node **jtlink2, Relids available_rels2)
655 : {
656 126468 : if (node == NULL)
657 7934 : return NULL;
658 118534 : if (IsA(node, SubLink))
659 : {
660 5404 : SubLink *sublink = (SubLink *) node;
661 : JoinExpr *j;
662 : Relids child_rels;
663 :
664 : /* Is it a convertible ANY or EXISTS clause? */
665 5404 : if (sublink->subLinkType == ANY_SUBLINK)
666 : {
667 : ScalarArrayOpExpr *saop;
668 :
669 4496 : if ((saop = convert_VALUES_to_ANY(root,
670 : sublink->testexpr,
671 4496 : (Query *) sublink->subselect)) != NULL)
672 :
673 : /*
674 : * The VALUES sequence was simplified. Nothing more to do
675 : * here.
676 : */
677 84 : return (Node *) saop;
678 :
679 4412 : if ((j = convert_ANY_sublink_to_join(root, sublink,
680 : available_rels1)) != NULL)
681 : {
682 : /* Yes; insert the new join node into the join tree */
683 4306 : j->larg = *jtlink1;
684 4306 : *jtlink1 = (Node *) j;
685 : /* Recursively process pulled-up jointree nodes */
686 4306 : j->rarg = pull_up_sublinks_jointree_recurse(root,
687 : j->rarg,
688 : &child_rels);
689 :
690 : /*
691 : * Now recursively process the pulled-up quals. Any inserted
692 : * joins can get stacked onto either j->larg or j->rarg,
693 : * depending on which rels they reference.
694 : */
695 4306 : j->quals = pull_up_sublinks_qual_recurse(root,
696 : j->quals,
697 : &j->larg,
698 : available_rels1,
699 : &j->rarg,
700 : child_rels);
701 : /* Return NULL representing constant TRUE */
702 4306 : return NULL;
703 : }
704 112 : if (available_rels2 != NULL &&
705 6 : (j = convert_ANY_sublink_to_join(root, sublink,
706 : available_rels2)) != NULL)
707 : {
708 : /* Yes; insert the new join node into the join tree */
709 0 : j->larg = *jtlink2;
710 0 : *jtlink2 = (Node *) j;
711 : /* Recursively process pulled-up jointree nodes */
712 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
713 : j->rarg,
714 : &child_rels);
715 :
716 : /*
717 : * Now recursively process the pulled-up quals. Any inserted
718 : * joins can get stacked onto either j->larg or j->rarg,
719 : * depending on which rels they reference.
720 : */
721 0 : j->quals = pull_up_sublinks_qual_recurse(root,
722 : j->quals,
723 : &j->larg,
724 : available_rels2,
725 : &j->rarg,
726 : child_rels);
727 : /* Return NULL representing constant TRUE */
728 0 : return NULL;
729 : }
730 : }
731 908 : else if (sublink->subLinkType == EXISTS_SUBLINK)
732 : {
733 848 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, false,
734 : available_rels1)) != NULL)
735 : {
736 : /* Yes; insert the new join node into the join tree */
737 700 : j->larg = *jtlink1;
738 700 : *jtlink1 = (Node *) j;
739 : /* Recursively process pulled-up jointree nodes */
740 700 : j->rarg = pull_up_sublinks_jointree_recurse(root,
741 : j->rarg,
742 : &child_rels);
743 :
744 : /*
745 : * Now recursively process the pulled-up quals. Any inserted
746 : * joins can get stacked onto either j->larg or j->rarg,
747 : * depending on which rels they reference.
748 : */
749 700 : j->quals = pull_up_sublinks_qual_recurse(root,
750 : j->quals,
751 : &j->larg,
752 : available_rels1,
753 : &j->rarg,
754 : child_rels);
755 : /* Return NULL representing constant TRUE */
756 700 : return NULL;
757 : }
758 180 : if (available_rels2 != NULL &&
759 32 : (j = convert_EXISTS_sublink_to_join(root, sublink, false,
760 : available_rels2)) != NULL)
761 : {
762 : /* Yes; insert the new join node into the join tree */
763 32 : j->larg = *jtlink2;
764 32 : *jtlink2 = (Node *) j;
765 : /* Recursively process pulled-up jointree nodes */
766 32 : j->rarg = pull_up_sublinks_jointree_recurse(root,
767 : j->rarg,
768 : &child_rels);
769 :
770 : /*
771 : * Now recursively process the pulled-up quals. Any inserted
772 : * joins can get stacked onto either j->larg or j->rarg,
773 : * depending on which rels they reference.
774 : */
775 32 : j->quals = pull_up_sublinks_qual_recurse(root,
776 : j->quals,
777 : &j->larg,
778 : available_rels2,
779 : &j->rarg,
780 : child_rels);
781 : /* Return NULL representing constant TRUE */
782 32 : return NULL;
783 : }
784 : }
785 : /* Else return it unmodified */
786 282 : return node;
787 : }
788 113130 : if (is_notclause(node))
789 : {
790 : /* If the immediate argument of NOT is EXISTS, try to convert */
791 7552 : SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
792 : JoinExpr *j;
793 : Relids child_rels;
794 :
795 7552 : if (sublink && IsA(sublink, SubLink))
796 : {
797 3030 : if (sublink->subLinkType == EXISTS_SUBLINK)
798 : {
799 2934 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, true,
800 : available_rels1)) != NULL)
801 : {
802 : /* Yes; insert the new join node into the join tree */
803 2920 : j->larg = *jtlink1;
804 2920 : *jtlink1 = (Node *) j;
805 : /* Recursively process pulled-up jointree nodes */
806 2920 : j->rarg = pull_up_sublinks_jointree_recurse(root,
807 : j->rarg,
808 : &child_rels);
809 :
810 : /*
811 : * Now recursively process the pulled-up quals. Because
812 : * we are underneath a NOT, we can't pull up sublinks that
813 : * reference the left-hand stuff, but it's still okay to
814 : * pull up sublinks referencing j->rarg.
815 : */
816 2920 : j->quals = pull_up_sublinks_qual_recurse(root,
817 : j->quals,
818 : &j->rarg,
819 : child_rels,
820 : NULL, NULL);
821 : /* Return NULL representing constant TRUE */
822 2920 : return NULL;
823 : }
824 14 : if (available_rels2 != NULL &&
825 0 : (j = convert_EXISTS_sublink_to_join(root, sublink, true,
826 : available_rels2)) != NULL)
827 : {
828 : /* Yes; insert the new join node into the join tree */
829 0 : j->larg = *jtlink2;
830 0 : *jtlink2 = (Node *) j;
831 : /* Recursively process pulled-up jointree nodes */
832 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
833 : j->rarg,
834 : &child_rels);
835 :
836 : /*
837 : * Now recursively process the pulled-up quals. Because
838 : * we are underneath a NOT, we can't pull up sublinks that
839 : * reference the left-hand stuff, but it's still okay to
840 : * pull up sublinks referencing j->rarg.
841 : */
842 0 : j->quals = pull_up_sublinks_qual_recurse(root,
843 : j->quals,
844 : &j->rarg,
845 : child_rels,
846 : NULL, NULL);
847 : /* Return NULL representing constant TRUE */
848 0 : return NULL;
849 : }
850 : }
851 : }
852 : /* Else return it unmodified */
853 4632 : return node;
854 : }
855 105578 : if (is_andclause(node))
856 : {
857 : /* Recurse into AND clause */
858 19696 : List *newclauses = NIL;
859 : ListCell *l;
860 :
861 76512 : foreach(l, ((BoolExpr *) node)->args)
862 : {
863 56816 : Node *oldclause = (Node *) lfirst(l);
864 : Node *newclause;
865 :
866 56816 : newclause = pull_up_sublinks_qual_recurse(root,
867 : oldclause,
868 : jtlink1,
869 : available_rels1,
870 : jtlink2,
871 : available_rels2);
872 56816 : if (newclause)
873 51174 : newclauses = lappend(newclauses, newclause);
874 : }
875 : /* We might have got back fewer clauses than we started with */
876 19696 : if (newclauses == NIL)
877 122 : return NULL;
878 19574 : else if (list_length(newclauses) == 1)
879 1128 : return (Node *) linitial(newclauses);
880 : else
881 18446 : return (Node *) make_andclause(newclauses);
882 : }
883 : /* Stop if not an AND */
884 85882 : return node;
885 : }
886 :
887 : /*
888 : * preprocess_function_rtes
889 : * Constant-simplify any FUNCTION RTEs in the FROM clause, and then
890 : * attempt to "inline" any that are set-returning functions.
891 : *
892 : * If an RTE_FUNCTION rtable entry invokes a set-returning function that
893 : * contains just a simple SELECT, we can convert the rtable entry to an
894 : * RTE_SUBQUERY entry exposing the SELECT directly. This is especially
895 : * useful if the subquery can then be "pulled up" for further optimization,
896 : * but we do it even if not, to reduce executor overhead.
897 : *
898 : * This has to be done before we have started to do any optimization of
899 : * subqueries, else any such steps wouldn't get applied to subqueries
900 : * obtained via inlining. However, we do it after pull_up_sublinks
901 : * so that we can inline any functions used in SubLink subselects.
902 : *
903 : * The reason for applying const-simplification at this stage is that
904 : * (a) we'd need to do it anyway to inline a SRF, and (b) by doing it now,
905 : * we can be sure that pull_up_constant_function() will see constants
906 : * if there are constants to be seen. This approach also guarantees
907 : * that every FUNCTION RTE has been const-simplified, allowing planner.c's
908 : * preprocess_expression() to skip doing it again.
909 : *
910 : * Like most of the planner, this feels free to scribble on its input data
911 : * structure.
912 : */
913 : void
914 571004 : preprocess_function_rtes(PlannerInfo *root)
915 : {
916 : ListCell *rt;
917 :
918 1474964 : foreach(rt, root->parse->rtable)
919 : {
920 903966 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
921 :
922 903966 : if (rte->rtekind == RTE_FUNCTION)
923 : {
924 : Query *funcquery;
925 :
926 : /* Apply const-simplification */
927 55672 : rte->functions = (List *)
928 55672 : eval_const_expressions(root, (Node *) rte->functions);
929 :
930 : /* Check safety of expansion, and expand if possible */
931 55672 : funcquery = inline_set_returning_function(root, rte);
932 55666 : if (funcquery)
933 : {
934 : /* Successful expansion, convert the RTE to a subquery */
935 222 : rte->rtekind = RTE_SUBQUERY;
936 222 : rte->subquery = funcquery;
937 222 : rte->security_barrier = false;
938 :
939 : /*
940 : * Clear fields that should not be set in a subquery RTE.
941 : * However, we leave rte->functions filled in for the moment,
942 : * in case makeWholeRowVar needs to consult it. We'll clear
943 : * it in setrefs.c (see add_rte_to_flat_rtable) so that this
944 : * abuse of the data structure doesn't escape the planner.
945 : */
946 222 : rte->funcordinality = false;
947 : }
948 : }
949 : }
950 570998 : }
951 :
952 : /*
953 : * expand_virtual_generated_columns
954 : * Expand all virtual generated column references in a query.
955 : *
956 : * This scans the rangetable for relations with virtual generated columns, and
957 : * replaces all Var nodes in the query that reference these columns with the
958 : * generation expressions. Note that we do not descend into subqueries; that
959 : * is taken care of when the subqueries are planned.
960 : *
961 : * This has to be done after we have pulled up any SubLinks within the query's
962 : * quals; otherwise any virtual generated column references within the SubLinks
963 : * that should be transformed into joins wouldn't get expanded.
964 : *
965 : * Returns a modified copy of the query tree, if any relations with virtual
966 : * generated columns are present.
967 : */
968 : Query *
969 570998 : expand_virtual_generated_columns(PlannerInfo *root)
970 : {
971 570998 : Query *parse = root->parse;
972 : int rt_index;
973 : ListCell *lc;
974 :
975 570998 : rt_index = 0;
976 1474958 : foreach(lc, parse->rtable)
977 : {
978 903960 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
979 : Relation rel;
980 : TupleDesc tupdesc;
981 :
982 903960 : ++rt_index;
983 :
984 : /*
985 : * Only normal relations can have virtual generated columns.
986 : */
987 903960 : if (rte->rtekind != RTE_RELATION)
988 428980 : continue;
989 :
990 474980 : rel = table_open(rte->relid, NoLock);
991 :
992 474980 : tupdesc = RelationGetDescr(rel);
993 474980 : if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
994 : {
995 1058 : List *tlist = NIL;
996 : pullup_replace_vars_context rvcontext;
997 :
998 3896 : for (int i = 0; i < tupdesc->natts; i++)
999 : {
1000 2838 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
1001 : TargetEntry *tle;
1002 :
1003 2838 : if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
1004 : {
1005 : Node *defexpr;
1006 :
1007 1352 : defexpr = build_generation_expression(rel, i + 1);
1008 1352 : ChangeVarNodes(defexpr, 1, rt_index, 0);
1009 :
1010 1352 : tle = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
1011 1352 : tlist = lappend(tlist, tle);
1012 : }
1013 : else
1014 : {
1015 : Var *var;
1016 :
1017 1486 : var = makeVar(rt_index,
1018 1486 : i + 1,
1019 : attr->atttypid,
1020 : attr->atttypmod,
1021 : attr->attcollation,
1022 : 0);
1023 :
1024 1486 : tle = makeTargetEntry((Expr *) var, i + 1, 0, false);
1025 1486 : tlist = lappend(tlist, tle);
1026 : }
1027 : }
1028 :
1029 : Assert(list_length(tlist) > 0);
1030 : Assert(!rte->lateral);
1031 :
1032 : /*
1033 : * The relation's targetlist items are now in the appropriate form
1034 : * to insert into the query, except that we may need to wrap them
1035 : * in PlaceHolderVars. Set up required context data for
1036 : * pullup_replace_vars.
1037 : */
1038 1058 : rvcontext.root = root;
1039 1058 : rvcontext.targetlist = tlist;
1040 1058 : rvcontext.target_rte = rte;
1041 1058 : rvcontext.result_relation = parse->resultRelation;
1042 : /* won't need these values */
1043 1058 : rvcontext.relids = NULL;
1044 1058 : rvcontext.nullinfo = NULL;
1045 : /* pass NULL for outer_hasSubLinks */
1046 1058 : rvcontext.outer_hasSubLinks = NULL;
1047 1058 : rvcontext.varno = rt_index;
1048 : /* this flag will be set below, if needed */
1049 1058 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
1050 : /* initialize cache array with indexes 0 .. length(tlist) */
1051 1058 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
1052 : sizeof(Node *));
1053 :
1054 : /*
1055 : * If the query uses grouping sets, we need a PlaceHolderVar for
1056 : * each expression of the relation's targetlist items. (See
1057 : * comments in pull_up_simple_subquery().)
1058 : */
1059 1058 : if (parse->groupingSets)
1060 12 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
1061 :
1062 : /*
1063 : * Apply pullup variable replacement throughout the query tree.
1064 : */
1065 1058 : parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
1066 : }
1067 :
1068 474980 : table_close(rel, NoLock);
1069 : }
1070 :
1071 570998 : return parse;
1072 : }
1073 :
1074 : /*
1075 : * pull_up_subqueries
1076 : * Look for subqueries in the rangetable that can be pulled up into
1077 : * the parent query. If the subquery has no special features like
1078 : * grouping/aggregation then we can merge it into the parent's jointree.
1079 : * Also, subqueries that are simple UNION ALL structures can be
1080 : * converted into "append relations".
1081 : */
1082 : void
1083 570998 : pull_up_subqueries(PlannerInfo *root)
1084 : {
1085 : /* Top level of jointree must always be a FromExpr */
1086 : Assert(IsA(root->parse->jointree, FromExpr));
1087 : /* Recursion starts with no containing join nor appendrel */
1088 1141990 : root->parse->jointree = (FromExpr *)
1089 570998 : pull_up_subqueries_recurse(root, (Node *) root->parse->jointree,
1090 : NULL, NULL);
1091 : /* We should still have a FromExpr */
1092 : Assert(IsA(root->parse->jointree, FromExpr));
1093 570992 : }
1094 :
1095 : /*
1096 : * pull_up_subqueries_recurse
1097 : * Recursive guts of pull_up_subqueries.
1098 : *
1099 : * This recursively processes the jointree and returns a modified jointree.
1100 : *
1101 : * If this jointree node is within either side of an outer join, then
1102 : * lowest_outer_join references the lowest such JoinExpr node; otherwise
1103 : * it is NULL. We use this to constrain the effects of LATERAL subqueries.
1104 : *
1105 : * If we are looking at a member subquery of an append relation,
1106 : * containing_appendrel describes that relation; else it is NULL.
1107 : * This forces use of the PlaceHolderVar mechanism for all non-Var targetlist
1108 : * items, and puts some additional restrictions on what can be pulled up.
1109 : *
1110 : * A tricky aspect of this code is that if we pull up a subquery we have
1111 : * to replace Vars that reference the subquery's outputs throughout the
1112 : * parent query, including quals attached to jointree nodes above the one
1113 : * we are currently processing! We handle this by being careful to maintain
1114 : * validity of the jointree structure while recursing, in the following sense:
1115 : * whenever we recurse, all qual expressions in the tree must be reachable
1116 : * from the top level, in case the recursive call needs to modify them.
1117 : *
1118 : * Notice also that we can't turn pullup_replace_vars loose on the whole
1119 : * jointree, because it'd return a mutated copy of the tree; we have to
1120 : * invoke it just on the quals, instead. This behavior is what makes it
1121 : * reasonable to pass lowest_outer_join as a pointer rather than some
1122 : * more-indirect way of identifying the lowest OJ. Likewise, we don't
1123 : * replace append_rel_list members but only their substructure, so the
1124 : * containing_appendrel reference is safe to use.
1125 : */
1126 : static Node *
1127 1399706 : pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
1128 : JoinExpr *lowest_outer_join,
1129 : AppendRelInfo *containing_appendrel)
1130 : {
1131 : /* Since this function recurses, it could be driven to stack overflow. */
1132 1399706 : check_stack_depth();
1133 : /* Also, since it's a bit expensive, let's check for query cancel. */
1134 1399706 : CHECK_FOR_INTERRUPTS();
1135 :
1136 : Assert(jtnode != NULL);
1137 1399706 : if (IsA(jtnode, RangeTblRef))
1138 : {
1139 722104 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1140 722104 : RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
1141 :
1142 : /*
1143 : * Is this a subquery RTE, and if so, is the subquery simple enough to
1144 : * pull up?
1145 : *
1146 : * If we are looking at an append-relation member, we can't pull it up
1147 : * unless is_safe_append_member says so.
1148 : */
1149 774694 : if (rte->rtekind == RTE_SUBQUERY &&
1150 90220 : is_simple_subquery(root, rte->subquery, rte, lowest_outer_join) &&
1151 7226 : (containing_appendrel == NULL ||
1152 7226 : is_safe_append_member(rte->subquery)))
1153 36614 : return pull_up_simple_subquery(root, jtnode, rte,
1154 : lowest_outer_join,
1155 : containing_appendrel);
1156 :
1157 : /*
1158 : * Alternatively, is it a simple UNION ALL subquery? If so, flatten
1159 : * into an "append relation".
1160 : *
1161 : * It's safe to do this regardless of whether this query is itself an
1162 : * appendrel member. (If you're thinking we should try to flatten the
1163 : * two levels of appendrel together, you're right; but we handle that
1164 : * in set_append_rel_pathlist, not here.)
1165 : */
1166 701466 : if (rte->rtekind == RTE_SUBQUERY &&
1167 15976 : is_simple_union_all(rte->subquery))
1168 4344 : return pull_up_simple_union_all(root, jtnode, rte);
1169 :
1170 : /*
1171 : * Or perhaps it's a simple VALUES RTE?
1172 : *
1173 : * We don't allow VALUES pullup below an outer join nor into an
1174 : * appendrel (such cases are impossible anyway at the moment).
1175 : */
1176 681146 : if (rte->rtekind == RTE_VALUES &&
1177 12734 : lowest_outer_join == NULL &&
1178 12734 : containing_appendrel == NULL &&
1179 12734 : is_simple_values(root, rte))
1180 4490 : return pull_up_simple_values(root, jtnode, rte);
1181 :
1182 : /*
1183 : * Or perhaps it's a FUNCTION RTE that we could inline?
1184 : */
1185 676656 : if (rte->rtekind == RTE_FUNCTION)
1186 55444 : return pull_up_constant_function(root, jtnode, rte,
1187 : containing_appendrel);
1188 :
1189 : /* Otherwise, do nothing at this node. */
1190 : }
1191 677602 : else if (IsA(jtnode, FromExpr))
1192 : {
1193 580596 : FromExpr *f = (FromExpr *) jtnode;
1194 : ListCell *l;
1195 :
1196 : Assert(containing_appendrel == NULL);
1197 : /* Recursively transform all the child nodes */
1198 1204888 : foreach(l, f->fromlist)
1199 : {
1200 624298 : lfirst(l) = pull_up_subqueries_recurse(root, lfirst(l),
1201 : lowest_outer_join,
1202 : NULL);
1203 : }
1204 : }
1205 97006 : else if (IsA(jtnode, JoinExpr))
1206 : {
1207 97006 : JoinExpr *j = (JoinExpr *) jtnode;
1208 :
1209 : Assert(containing_appendrel == NULL);
1210 : /* Recurse, being careful to tell myself when inside outer join */
1211 97006 : switch (j->jointype)
1212 : {
1213 40074 : case JOIN_INNER:
1214 40074 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1215 : lowest_outer_join,
1216 : NULL);
1217 40074 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1218 : lowest_outer_join,
1219 : NULL);
1220 40074 : break;
1221 54706 : case JOIN_LEFT:
1222 : case JOIN_SEMI:
1223 : case JOIN_ANTI:
1224 54706 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1225 : j,
1226 : NULL);
1227 54706 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1228 : j,
1229 : NULL);
1230 54706 : break;
1231 1090 : case JOIN_FULL:
1232 1090 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1233 : j,
1234 : NULL);
1235 1090 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1236 : j,
1237 : NULL);
1238 1090 : break;
1239 1136 : case JOIN_RIGHT:
1240 1136 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1241 : j,
1242 : NULL);
1243 1136 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1244 : j,
1245 : NULL);
1246 1136 : break;
1247 0 : default:
1248 0 : elog(ERROR, "unrecognized join type: %d",
1249 : (int) j->jointype);
1250 : break;
1251 : }
1252 : }
1253 : else
1254 0 : elog(ERROR, "unrecognized node type: %d",
1255 : (int) nodeTag(jtnode));
1256 1298808 : return jtnode;
1257 : }
1258 :
1259 : /*
1260 : * pull_up_simple_subquery
1261 : * Attempt to pull up a single simple subquery.
1262 : *
1263 : * jtnode is a RangeTblRef that has been tentatively identified as a simple
1264 : * subquery by pull_up_subqueries. We return the replacement jointree node,
1265 : * or jtnode itself if we determine that the subquery can't be pulled up
1266 : * after all.
1267 : *
1268 : * rte is the RangeTblEntry referenced by jtnode. Remaining parameters are
1269 : * as for pull_up_subqueries_recurse.
1270 : */
1271 : static Node *
1272 36614 : pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
1273 : JoinExpr *lowest_outer_join,
1274 : AppendRelInfo *containing_appendrel)
1275 : {
1276 36614 : Query *parse = root->parse;
1277 36614 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1278 : Query *subquery;
1279 : PlannerInfo *subroot;
1280 : int rtoffset;
1281 : pullup_replace_vars_context rvcontext;
1282 : ListCell *lc;
1283 :
1284 : /*
1285 : * Make a modifiable copy of the subquery to hack on, so that the RTE will
1286 : * be left unchanged in case we decide below that we can't pull it up
1287 : * after all.
1288 : */
1289 36614 : subquery = copyObject(rte->subquery);
1290 :
1291 : /*
1292 : * Create a PlannerInfo data structure for this subquery.
1293 : *
1294 : * NOTE: the next few steps should match the first processing in
1295 : * subquery_planner(). Can we refactor to avoid code duplication, or
1296 : * would that just make things uglier?
1297 : */
1298 36614 : subroot = makeNode(PlannerInfo);
1299 36614 : subroot->parse = subquery;
1300 36614 : subroot->glob = root->glob;
1301 36614 : subroot->query_level = root->query_level;
1302 36614 : subroot->parent_root = root->parent_root;
1303 36614 : subroot->plan_params = NIL;
1304 36614 : subroot->outer_params = NULL;
1305 36614 : subroot->planner_cxt = CurrentMemoryContext;
1306 36614 : subroot->init_plans = NIL;
1307 36614 : subroot->cte_plan_ids = NIL;
1308 36614 : subroot->multiexpr_params = NIL;
1309 36614 : subroot->join_domains = NIL;
1310 36614 : subroot->eq_classes = NIL;
1311 36614 : subroot->ec_merging_done = false;
1312 36614 : subroot->last_rinfo_serial = 0;
1313 36614 : subroot->all_result_relids = NULL;
1314 36614 : subroot->leaf_result_relids = NULL;
1315 36614 : subroot->append_rel_list = NIL;
1316 36614 : subroot->row_identity_vars = NIL;
1317 36614 : subroot->rowMarks = NIL;
1318 36614 : memset(subroot->upper_rels, 0, sizeof(subroot->upper_rels));
1319 36614 : memset(subroot->upper_targets, 0, sizeof(subroot->upper_targets));
1320 36614 : subroot->processed_groupClause = NIL;
1321 36614 : subroot->processed_distinctClause = NIL;
1322 36614 : subroot->processed_tlist = NIL;
1323 36614 : subroot->update_colnos = NIL;
1324 36614 : subroot->grouping_map = NULL;
1325 36614 : subroot->minmax_aggs = NIL;
1326 36614 : subroot->qual_security_level = 0;
1327 36614 : subroot->placeholdersFrozen = false;
1328 36614 : subroot->hasRecursion = false;
1329 36614 : subroot->wt_param_id = -1;
1330 36614 : subroot->non_recursive_path = NULL;
1331 : /* We don't currently need a top JoinDomain for the subroot */
1332 :
1333 : /* No CTEs to worry about */
1334 : Assert(subquery->cteList == NIL);
1335 :
1336 : /*
1337 : * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
1338 : * that we don't need so many special cases to deal with that situation.
1339 : */
1340 36614 : replace_empty_jointree(subquery);
1341 :
1342 : /*
1343 : * Pull up any SubLinks within the subquery's quals, so that we don't
1344 : * leave unoptimized SubLinks behind.
1345 : */
1346 36614 : if (subquery->hasSubLinks)
1347 2308 : pull_up_sublinks(subroot);
1348 :
1349 : /*
1350 : * Similarly, preprocess its function RTEs to inline any set-returning
1351 : * functions in its rangetable.
1352 : */
1353 36614 : preprocess_function_rtes(subroot);
1354 :
1355 : /*
1356 : * Scan the rangetable for relations with virtual generated columns, and
1357 : * replace all Var nodes in the query that reference these columns with
1358 : * the generation expressions.
1359 : */
1360 36614 : subquery = subroot->parse = expand_virtual_generated_columns(subroot);
1361 :
1362 : /*
1363 : * Recursively pull up the subquery's subqueries, so that
1364 : * pull_up_subqueries' processing is complete for its jointree and
1365 : * rangetable.
1366 : *
1367 : * Note: it's okay that the subquery's recursion starts with NULL for
1368 : * containing-join info, even if we are within an outer join in the upper
1369 : * query; the lower query starts with a clean slate for outer-join
1370 : * semantics. Likewise, we needn't pass down appendrel state.
1371 : */
1372 36614 : pull_up_subqueries(subroot);
1373 :
1374 : /*
1375 : * Now we must recheck whether the subquery is still simple enough to pull
1376 : * up. If not, abandon processing it.
1377 : *
1378 : * We don't really need to recheck all the conditions involved, but it's
1379 : * easier just to keep this "if" looking the same as the one in
1380 : * pull_up_subqueries_recurse.
1381 : */
1382 36614 : if (is_simple_subquery(root, subquery, rte, lowest_outer_join) &&
1383 6210 : (containing_appendrel == NULL || is_safe_append_member(subquery)))
1384 : {
1385 : /* good to go */
1386 : }
1387 : else
1388 : {
1389 : /*
1390 : * Give up, return unmodified RangeTblRef.
1391 : *
1392 : * Note: The work we just did will be redone when the subquery gets
1393 : * planned on its own. Perhaps we could avoid that by storing the
1394 : * modified subquery back into the rangetable, but I'm not gonna risk
1395 : * it now.
1396 : */
1397 202 : return jtnode;
1398 : }
1399 :
1400 : /*
1401 : * We must flatten any join alias Vars in the subquery's targetlist,
1402 : * because pulling up the subquery's subqueries might have changed their
1403 : * expansions into arbitrary expressions, which could affect
1404 : * pullup_replace_vars' decisions about whether PlaceHolderVar wrappers
1405 : * are needed for tlist entries. (Likely it'd be better to do
1406 : * flatten_join_alias_vars on the whole query tree at some earlier stage,
1407 : * maybe even in the rewriter; but for now let's just fix this case here.)
1408 : */
1409 36412 : subquery->targetList = (List *)
1410 36412 : flatten_join_alias_vars(subroot, subroot->parse,
1411 36412 : (Node *) subquery->targetList);
1412 :
1413 : /*
1414 : * Adjust level-0 varnos in subquery so that we can append its rangetable
1415 : * to upper query's. We have to fix the subquery's append_rel_list as
1416 : * well.
1417 : */
1418 36412 : rtoffset = list_length(parse->rtable);
1419 36412 : OffsetVarNodes((Node *) subquery, rtoffset, 0);
1420 36412 : OffsetVarNodes((Node *) subroot->append_rel_list, rtoffset, 0);
1421 :
1422 : /*
1423 : * Upper-level vars in subquery are now one level closer to their parent
1424 : * than before.
1425 : */
1426 36412 : IncrementVarSublevelsUp((Node *) subquery, -1, 1);
1427 36412 : IncrementVarSublevelsUp((Node *) subroot->append_rel_list, -1, 1);
1428 :
1429 : /*
1430 : * The subquery's targetlist items are now in the appropriate form to
1431 : * insert into the top query, except that we may need to wrap them in
1432 : * PlaceHolderVars. Set up required context data for pullup_replace_vars.
1433 : * (Note that we should include the subquery's inner joins in relids,
1434 : * since it may include join alias vars referencing them.)
1435 : */
1436 36412 : rvcontext.root = root;
1437 36412 : rvcontext.targetlist = subquery->targetList;
1438 36412 : rvcontext.target_rte = rte;
1439 36412 : rvcontext.result_relation = 0;
1440 36412 : if (rte->lateral)
1441 : {
1442 1138 : rvcontext.relids = get_relids_in_jointree((Node *) subquery->jointree,
1443 : true, true);
1444 1138 : rvcontext.nullinfo = get_nullingrels(parse);
1445 : }
1446 : else /* won't need these values */
1447 : {
1448 35274 : rvcontext.relids = NULL;
1449 35274 : rvcontext.nullinfo = NULL;
1450 : }
1451 36412 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1452 36412 : rvcontext.varno = varno;
1453 : /* this flag will be set below, if needed */
1454 36412 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
1455 : /* initialize cache array with indexes 0 .. length(tlist) */
1456 36412 : rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
1457 : sizeof(Node *));
1458 :
1459 : /*
1460 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
1461 : * each expression of the subquery's targetlist items. This ensures that
1462 : * expressions retain their separate identity so that they will match
1463 : * grouping set columns when appropriate. (It'd be sufficient to wrap
1464 : * values used in grouping set columns, and do so only in non-aggregated
1465 : * portions of the tlist and havingQual, but that would require a lot of
1466 : * infrastructure that pullup_replace_vars hasn't currently got.)
1467 : */
1468 36412 : if (parse->groupingSets)
1469 332 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
1470 :
1471 : /*
1472 : * Replace all of the top query's references to the subquery's outputs
1473 : * with copies of the adjusted subtlist items, being careful not to
1474 : * replace any of the jointree structure.
1475 : */
1476 36412 : perform_pullup_replace_vars(root, &rvcontext,
1477 : containing_appendrel);
1478 :
1479 : /*
1480 : * If the subquery had a LATERAL marker, propagate that to any of its
1481 : * child RTEs that could possibly now contain lateral cross-references.
1482 : * The children might or might not contain any actual lateral
1483 : * cross-references, but we have to mark the pulled-up child RTEs so that
1484 : * later planner stages will check for such.
1485 : */
1486 36406 : if (rte->lateral)
1487 : {
1488 2660 : foreach(lc, subquery->rtable)
1489 : {
1490 1522 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(lc);
1491 :
1492 1522 : switch (child_rte->rtekind)
1493 : {
1494 684 : case RTE_RELATION:
1495 684 : if (child_rte->tablesample)
1496 36 : child_rte->lateral = true;
1497 684 : break;
1498 268 : case RTE_SUBQUERY:
1499 : case RTE_FUNCTION:
1500 : case RTE_VALUES:
1501 : case RTE_TABLEFUNC:
1502 268 : child_rte->lateral = true;
1503 268 : break;
1504 570 : case RTE_JOIN:
1505 : case RTE_CTE:
1506 : case RTE_NAMEDTUPLESTORE:
1507 : case RTE_RESULT:
1508 : case RTE_GROUP:
1509 : /* these can't contain any lateral references */
1510 570 : break;
1511 : }
1512 1522 : }
1513 : }
1514 :
1515 : /*
1516 : * Now append the adjusted rtable entries and their perminfos to upper
1517 : * query. (We hold off until after fixing the upper rtable entries; no
1518 : * point in running that code on the subquery ones too.)
1519 : */
1520 36406 : CombineRangeTables(&parse->rtable, &parse->rteperminfos,
1521 : subquery->rtable, subquery->rteperminfos);
1522 :
1523 : /*
1524 : * Pull up any FOR UPDATE/SHARE markers, too. (OffsetVarNodes already
1525 : * adjusted the marker rtindexes, so just concat the lists.)
1526 : */
1527 36406 : parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
1528 :
1529 : /*
1530 : * We also have to fix the relid sets of any PlaceHolderVar nodes in the
1531 : * parent query. (This could perhaps be done by pullup_replace_vars(),
1532 : * but it seems cleaner to use two passes.) Note in particular that any
1533 : * PlaceHolderVar nodes just created by pullup_replace_vars() will be
1534 : * adjusted, so having created them with the subquery's varno is correct.
1535 : *
1536 : * Likewise, relids appearing in AppendRelInfo nodes have to be fixed. We
1537 : * already checked that this won't require introducing multiple subrelids
1538 : * into the single-slot AppendRelInfo structs.
1539 : */
1540 36406 : if (root->glob->lastPHId != 0 || root->append_rel_list)
1541 : {
1542 : Relids subrelids;
1543 :
1544 7858 : subrelids = get_relids_in_jointree((Node *) subquery->jointree,
1545 : true, false);
1546 7858 : if (root->glob->lastPHId != 0)
1547 1892 : substitute_phv_relids((Node *) parse, varno, subrelids);
1548 7858 : fix_append_rel_relids(root, varno, subrelids);
1549 : }
1550 :
1551 : /*
1552 : * And now add subquery's AppendRelInfos to our list.
1553 : */
1554 72812 : root->append_rel_list = list_concat(root->append_rel_list,
1555 36406 : subroot->append_rel_list);
1556 :
1557 : /*
1558 : * We don't have to do the equivalent bookkeeping for outer-join info,
1559 : * because that hasn't been set up yet. placeholder_list likewise.
1560 : */
1561 : Assert(root->join_info_list == NIL);
1562 : Assert(subroot->join_info_list == NIL);
1563 : Assert(root->placeholder_list == NIL);
1564 : Assert(subroot->placeholder_list == NIL);
1565 :
1566 : /*
1567 : * We no longer need the RTE's copy of the subquery's query tree. Getting
1568 : * rid of it saves nothing in particular so far as this level of query is
1569 : * concerned; but if this query level is in turn pulled up into a parent,
1570 : * we'd waste cycles copying the now-unused query tree.
1571 : */
1572 36406 : rte->subquery = NULL;
1573 :
1574 : /*
1575 : * Miscellaneous housekeeping.
1576 : *
1577 : * Although replace_rte_variables() faithfully updated parse->hasSubLinks
1578 : * if it copied any SubLinks out of the subquery's targetlist, we still
1579 : * could have SubLinks added to the query in the expressions of FUNCTION
1580 : * and VALUES RTEs copied up from the subquery. So it's necessary to copy
1581 : * subquery->hasSubLinks anyway. Perhaps this can be improved someday.
1582 : */
1583 36406 : parse->hasSubLinks |= subquery->hasSubLinks;
1584 :
1585 : /* If subquery had any RLS conditions, now main query does too */
1586 36406 : parse->hasRowSecurity |= subquery->hasRowSecurity;
1587 :
1588 : /*
1589 : * subquery won't be pulled up if it hasAggs, hasWindowFuncs, or
1590 : * hasTargetSRFs, so no work needed on those flags
1591 : */
1592 :
1593 : /*
1594 : * Return the adjusted subquery jointree to replace the RangeTblRef entry
1595 : * in parent's jointree; or, if the FromExpr is degenerate, just return
1596 : * its single member.
1597 : */
1598 : Assert(IsA(subquery->jointree, FromExpr));
1599 : Assert(subquery->jointree->fromlist != NIL);
1600 67846 : if (subquery->jointree->quals == NULL &&
1601 31440 : list_length(subquery->jointree->fromlist) == 1)
1602 31126 : return (Node *) linitial(subquery->jointree->fromlist);
1603 :
1604 5280 : return (Node *) subquery->jointree;
1605 : }
1606 :
1607 : /*
1608 : * pull_up_simple_union_all
1609 : * Pull up a single simple UNION ALL subquery.
1610 : *
1611 : * jtnode is a RangeTblRef that has been identified as a simple UNION ALL
1612 : * subquery by pull_up_subqueries. We pull up the leaf subqueries and
1613 : * build an "append relation" for the union set. The result value is just
1614 : * jtnode, since we don't actually need to change the query jointree.
1615 : */
1616 : static Node *
1617 4344 : pull_up_simple_union_all(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1618 : {
1619 4344 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1620 4344 : Query *subquery = rte->subquery;
1621 4344 : int rtoffset = list_length(root->parse->rtable);
1622 : List *rtable;
1623 :
1624 : /*
1625 : * Make a modifiable copy of the subquery's rtable, so we can adjust
1626 : * upper-level Vars in it. There are no such Vars in the setOperations
1627 : * tree proper, so fixing the rtable should be sufficient.
1628 : */
1629 4344 : rtable = copyObject(subquery->rtable);
1630 :
1631 : /*
1632 : * Upper-level vars in subquery are now one level closer to their parent
1633 : * than before. We don't have to worry about offsetting varnos, though,
1634 : * because the UNION leaf queries can't cross-reference each other.
1635 : */
1636 4344 : IncrementVarSublevelsUp_rtable(rtable, -1, 1);
1637 :
1638 : /*
1639 : * If the UNION ALL subquery had a LATERAL marker, propagate that to all
1640 : * its children. The individual children might or might not contain any
1641 : * actual lateral cross-references, but we have to mark the pulled-up
1642 : * child RTEs so that later planner stages will check for such.
1643 : */
1644 4344 : if (rte->lateral)
1645 : {
1646 : ListCell *rt;
1647 :
1648 198 : foreach(rt, rtable)
1649 : {
1650 132 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(rt);
1651 :
1652 : Assert(child_rte->rtekind == RTE_SUBQUERY);
1653 132 : child_rte->lateral = true;
1654 : }
1655 : }
1656 :
1657 : /*
1658 : * Append child RTEs (and their perminfos) to parent rtable.
1659 : */
1660 4344 : CombineRangeTables(&root->parse->rtable, &root->parse->rteperminfos,
1661 : rtable, subquery->rteperminfos);
1662 :
1663 : /*
1664 : * Recursively scan the subquery's setOperations tree and add
1665 : * AppendRelInfo nodes for leaf subqueries to the parent's
1666 : * append_rel_list. Also apply pull_up_subqueries to the leaf subqueries.
1667 : */
1668 : Assert(subquery->setOperations);
1669 4344 : pull_up_union_leaf_queries(subquery->setOperations, root, varno, subquery,
1670 : rtoffset);
1671 :
1672 : /*
1673 : * Mark the parent as an append relation.
1674 : */
1675 4344 : rte->inh = true;
1676 :
1677 4344 : return jtnode;
1678 : }
1679 :
1680 : /*
1681 : * pull_up_union_leaf_queries -- recursive guts of pull_up_simple_union_all
1682 : *
1683 : * Build an AppendRelInfo for each leaf query in the setop tree, and then
1684 : * apply pull_up_subqueries to the leaf query.
1685 : *
1686 : * Note that setOpQuery is the Query containing the setOp node, whose tlist
1687 : * contains references to all the setop output columns. When called from
1688 : * pull_up_simple_union_all, this is *not* the same as root->parse, which is
1689 : * the parent Query we are pulling up into.
1690 : *
1691 : * parentRTindex is the appendrel parent's index in root->parse->rtable.
1692 : *
1693 : * The child RTEs have already been copied to the parent. childRToffset
1694 : * tells us where in the parent's range table they were copied. When called
1695 : * from flatten_simple_union_all, childRToffset is 0 since the child RTEs
1696 : * were already in root->parse->rtable and no RT index adjustment is needed.
1697 : */
1698 : static void
1699 16016 : pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
1700 : Query *setOpQuery, int childRToffset)
1701 : {
1702 16016 : if (IsA(setOp, RangeTblRef))
1703 : {
1704 10398 : RangeTblRef *rtr = (RangeTblRef *) setOp;
1705 : int childRTindex;
1706 : AppendRelInfo *appinfo;
1707 :
1708 : /*
1709 : * Calculate the index in the parent's range table
1710 : */
1711 10398 : childRTindex = childRToffset + rtr->rtindex;
1712 :
1713 : /*
1714 : * Build a suitable AppendRelInfo, and attach to parent's list.
1715 : */
1716 10398 : appinfo = makeNode(AppendRelInfo);
1717 10398 : appinfo->parent_relid = parentRTindex;
1718 10398 : appinfo->child_relid = childRTindex;
1719 10398 : appinfo->parent_reltype = InvalidOid;
1720 10398 : appinfo->child_reltype = InvalidOid;
1721 10398 : make_setop_translation_list(setOpQuery, childRTindex, appinfo);
1722 10398 : appinfo->parent_reloid = InvalidOid;
1723 10398 : root->append_rel_list = lappend(root->append_rel_list, appinfo);
1724 :
1725 : /*
1726 : * Recursively apply pull_up_subqueries to the new child RTE. (We
1727 : * must build the AppendRelInfo first, because this will modify it;
1728 : * indeed, that's the only part of the upper query where Vars
1729 : * referencing childRTindex can exist at this point.)
1730 : *
1731 : * Note that we can pass NULL for containing-join info even if we're
1732 : * actually under an outer join, because the child's expressions
1733 : * aren't going to propagate up to the join. Also, we ignore the
1734 : * possibility that pull_up_subqueries_recurse() returns a different
1735 : * jointree node than what we pass it; if it does, the important thing
1736 : * is that it replaced the child relid in the AppendRelInfo node.
1737 : */
1738 10398 : rtr = makeNode(RangeTblRef);
1739 10398 : rtr->rtindex = childRTindex;
1740 10398 : (void) pull_up_subqueries_recurse(root, (Node *) rtr,
1741 : NULL, appinfo);
1742 : }
1743 5618 : else if (IsA(setOp, SetOperationStmt))
1744 : {
1745 5618 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1746 :
1747 : /* Recurse to reach leaf queries */
1748 5618 : pull_up_union_leaf_queries(op->larg, root, parentRTindex, setOpQuery,
1749 : childRToffset);
1750 5618 : pull_up_union_leaf_queries(op->rarg, root, parentRTindex, setOpQuery,
1751 : childRToffset);
1752 : }
1753 : else
1754 : {
1755 0 : elog(ERROR, "unrecognized node type: %d",
1756 : (int) nodeTag(setOp));
1757 : }
1758 16016 : }
1759 :
1760 : /*
1761 : * make_setop_translation_list
1762 : * Build the list of translations from parent Vars to child Vars for
1763 : * a UNION ALL member. (At this point it's just a simple list of
1764 : * referencing Vars, but if we succeed in pulling up the member
1765 : * subquery, the Vars will get replaced by pulled-up expressions.)
1766 : * Also create the rather trivial reverse-translation array.
1767 : */
1768 : static void
1769 10398 : make_setop_translation_list(Query *query, int newvarno,
1770 : AppendRelInfo *appinfo)
1771 : {
1772 10398 : List *vars = NIL;
1773 : AttrNumber *pcolnos;
1774 : ListCell *l;
1775 :
1776 : /* Initialize reverse-translation array with all entries zero */
1777 : /* (entries for resjunk columns will stay that way) */
1778 10398 : appinfo->num_child_cols = list_length(query->targetList);
1779 10398 : appinfo->parent_colnos = pcolnos =
1780 10398 : (AttrNumber *) palloc0(appinfo->num_child_cols * sizeof(AttrNumber));
1781 :
1782 26566 : foreach(l, query->targetList)
1783 : {
1784 16168 : TargetEntry *tle = (TargetEntry *) lfirst(l);
1785 :
1786 16168 : if (tle->resjunk)
1787 0 : continue;
1788 :
1789 16168 : vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
1790 16168 : pcolnos[tle->resno - 1] = tle->resno;
1791 : }
1792 :
1793 10398 : appinfo->translated_vars = vars;
1794 10398 : }
1795 :
1796 : /*
1797 : * is_simple_subquery
1798 : * Check a subquery in the range table to see if it's simple enough
1799 : * to pull up into the parent query.
1800 : *
1801 : * rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
1802 : * (Note subquery is not necessarily equal to rte->subquery; it could be a
1803 : * processed copy of that.)
1804 : * lowest_outer_join is the lowest outer join above the subquery, or NULL.
1805 : */
1806 : static bool
1807 89204 : is_simple_subquery(PlannerInfo *root, Query *subquery, RangeTblEntry *rte,
1808 : JoinExpr *lowest_outer_join)
1809 : {
1810 : /*
1811 : * Let's just make sure it's a valid subselect ...
1812 : */
1813 89204 : if (!IsA(subquery, Query) ||
1814 89204 : subquery->commandType != CMD_SELECT)
1815 0 : elog(ERROR, "subquery is bogus");
1816 :
1817 : /*
1818 : * Can't currently pull up a query with setops (unless it's simple UNION
1819 : * ALL, which is handled by a different code path). Maybe after querytree
1820 : * redesign...
1821 : */
1822 89204 : if (subquery->setOperations)
1823 5084 : return false;
1824 :
1825 : /*
1826 : * Can't pull up a subquery involving grouping, aggregation, SRFs,
1827 : * sorting, limiting, or WITH. (XXX WITH could possibly be allowed later)
1828 : *
1829 : * We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
1830 : * clauses, because pullup would cause the locking to occur semantically
1831 : * higher than it should. Implicit FOR UPDATE/SHARE is okay because in
1832 : * that case the locking was originally declared in the upper query
1833 : * anyway.
1834 : */
1835 84120 : if (subquery->hasAggs ||
1836 82600 : subquery->hasWindowFuncs ||
1837 82214 : subquery->hasTargetSRFs ||
1838 78006 : subquery->groupClause ||
1839 77926 : subquery->groupingSets ||
1840 77926 : subquery->havingQual ||
1841 77926 : subquery->sortClause ||
1842 77052 : subquery->distinctClause ||
1843 76794 : subquery->limitOffset ||
1844 76356 : subquery->limitCount ||
1845 76082 : subquery->hasForUpdate ||
1846 75552 : subquery->cteList)
1847 8736 : return false;
1848 :
1849 : /*
1850 : * Don't pull up if the RTE represents a security-barrier view; we
1851 : * couldn't prevent information leakage once the RTE's Vars are scattered
1852 : * about in the upper query.
1853 : */
1854 75384 : if (rte->security_barrier)
1855 868 : return false;
1856 :
1857 : /*
1858 : * If the subquery is LATERAL, check for pullup restrictions from that.
1859 : */
1860 74516 : if (rte->lateral)
1861 : {
1862 : bool restricted;
1863 : Relids safe_upper_varnos;
1864 :
1865 : /*
1866 : * The subquery's WHERE and JOIN/ON quals mustn't contain any lateral
1867 : * references to rels outside a higher outer join (including the case
1868 : * where the outer join is within the subquery itself). In such a
1869 : * case, pulling up would result in a situation where we need to
1870 : * postpone quals from below an outer join to above it, which is
1871 : * probably completely wrong and in any case is a complication that
1872 : * doesn't seem worth addressing at the moment.
1873 : */
1874 2366 : if (lowest_outer_join != NULL)
1875 : {
1876 1336 : restricted = true;
1877 1336 : safe_upper_varnos = get_relids_in_jointree((Node *) lowest_outer_join,
1878 : true, true);
1879 : }
1880 : else
1881 : {
1882 1030 : restricted = false;
1883 1030 : safe_upper_varnos = NULL; /* doesn't matter */
1884 : }
1885 :
1886 2366 : if (jointree_contains_lateral_outer_refs(root,
1887 2366 : (Node *) subquery->jointree,
1888 : restricted, safe_upper_varnos))
1889 24 : return false;
1890 :
1891 : /*
1892 : * If there's an outer join above the LATERAL subquery, also disallow
1893 : * pullup if the subquery's targetlist has any references to rels
1894 : * outside the outer join, since these might get pulled into quals
1895 : * above the subquery (but in or below the outer join) and then lead
1896 : * to qual-postponement issues similar to the case checked for above.
1897 : * (We wouldn't need to prevent pullup if no such references appear in
1898 : * outer-query quals, but we don't have enough info here to check
1899 : * that. Also, maybe this restriction could be removed if we forced
1900 : * such refs to be wrapped in PlaceHolderVars, even when they're below
1901 : * the nearest outer join? But it's a pretty hokey usage, so not
1902 : * clear this is worth sweating over.)
1903 : *
1904 : * If you change this, see also the comments about lateral references
1905 : * in pullup_replace_vars_callback().
1906 : */
1907 2342 : if (lowest_outer_join != NULL)
1908 : {
1909 1336 : Relids lvarnos = pull_varnos_of_level(root,
1910 1336 : (Node *) subquery->targetList,
1911 : 1);
1912 :
1913 1336 : if (!bms_is_subset(lvarnos, safe_upper_varnos))
1914 12 : return false;
1915 : }
1916 : }
1917 :
1918 : /*
1919 : * Don't pull up a subquery that has any volatile functions in its
1920 : * targetlist. Otherwise we might introduce multiple evaluations of these
1921 : * functions, if they get copied to multiple places in the upper query,
1922 : * leading to surprising results. (Note: the PlaceHolderVar mechanism
1923 : * doesn't quite guarantee single evaluation; else we could pull up anyway
1924 : * and just wrap such items in PlaceHolderVars ...)
1925 : */
1926 74480 : if (contain_volatile_functions((Node *) subquery->targetList))
1927 248 : return false;
1928 :
1929 74232 : return true;
1930 : }
1931 :
1932 : /*
1933 : * pull_up_simple_values
1934 : * Pull up a single simple VALUES RTE.
1935 : *
1936 : * jtnode is a RangeTblRef that has been identified as a simple VALUES RTE
1937 : * by pull_up_subqueries. We always return a RangeTblRef representing a
1938 : * RESULT RTE to replace it (all failure cases should have been detected by
1939 : * is_simple_values()). Actually, what we return is just jtnode, because
1940 : * we replace the VALUES RTE in the rangetable with the RESULT RTE.
1941 : *
1942 : * rte is the RangeTblEntry referenced by jtnode. Because of the limited
1943 : * possible usage of VALUES RTEs, we do not need the remaining parameters
1944 : * of pull_up_subqueries_recurse.
1945 : */
1946 : static Node *
1947 4490 : pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1948 : {
1949 4490 : Query *parse = root->parse;
1950 4490 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1951 : List *values_list;
1952 : List *tlist;
1953 : AttrNumber attrno;
1954 : pullup_replace_vars_context rvcontext;
1955 : ListCell *lc;
1956 :
1957 : Assert(rte->rtekind == RTE_VALUES);
1958 : Assert(list_length(rte->values_lists) == 1);
1959 :
1960 : /*
1961 : * Need a modifiable copy of the VALUES list to hack on, just in case it's
1962 : * multiply referenced.
1963 : */
1964 4490 : values_list = copyObject(linitial(rte->values_lists));
1965 :
1966 : /*
1967 : * The VALUES RTE can't contain any Vars of level zero, let alone any that
1968 : * are join aliases, so no need to flatten join alias Vars.
1969 : */
1970 : Assert(!contain_vars_of_level((Node *) values_list, 0));
1971 :
1972 : /*
1973 : * Set up required context data for pullup_replace_vars. In particular,
1974 : * we have to make the VALUES list look like a subquery targetlist.
1975 : */
1976 4490 : tlist = NIL;
1977 4490 : attrno = 1;
1978 9664 : foreach(lc, values_list)
1979 : {
1980 5174 : tlist = lappend(tlist,
1981 5174 : makeTargetEntry((Expr *) lfirst(lc),
1982 : attrno,
1983 : NULL,
1984 : false));
1985 5174 : attrno++;
1986 : }
1987 4490 : rvcontext.root = root;
1988 4490 : rvcontext.targetlist = tlist;
1989 4490 : rvcontext.target_rte = rte;
1990 4490 : rvcontext.result_relation = 0;
1991 4490 : rvcontext.relids = NULL; /* can't be any lateral references here */
1992 4490 : rvcontext.nullinfo = NULL;
1993 4490 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1994 4490 : rvcontext.varno = varno;
1995 4490 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
1996 : /* initialize cache array with indexes 0 .. length(tlist) */
1997 4490 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
1998 : sizeof(Node *));
1999 :
2000 : /*
2001 : * Replace all of the top query's references to the RTE's outputs with
2002 : * copies of the adjusted VALUES expressions, being careful not to replace
2003 : * any of the jointree structure. We can assume there's no outer joins or
2004 : * appendrels in the dummy Query that surrounds a VALUES RTE.
2005 : */
2006 4490 : perform_pullup_replace_vars(root, &rvcontext, NULL);
2007 :
2008 : /*
2009 : * There should be no appendrels to fix, nor any outer joins and hence no
2010 : * PlaceHolderVars.
2011 : */
2012 : Assert(root->append_rel_list == NIL);
2013 : Assert(root->join_info_list == NIL);
2014 : Assert(root->placeholder_list == NIL);
2015 :
2016 : /*
2017 : * Replace the VALUES RTE with a RESULT RTE. The VALUES RTE is the only
2018 : * rtable entry in the current query level, so this is easy.
2019 : */
2020 : Assert(list_length(parse->rtable) == 1);
2021 :
2022 : /* Create suitable RTE */
2023 4490 : rte = makeNode(RangeTblEntry);
2024 4490 : rte->rtekind = RTE_RESULT;
2025 4490 : rte->eref = makeAlias("*RESULT*", NIL);
2026 :
2027 : /* Replace rangetable */
2028 4490 : parse->rtable = list_make1(rte);
2029 :
2030 : /* We could manufacture a new RangeTblRef, but the one we have is fine */
2031 : Assert(varno == 1);
2032 :
2033 4490 : return jtnode;
2034 : }
2035 :
2036 : /*
2037 : * is_simple_values
2038 : * Check a VALUES RTE in the range table to see if it's simple enough
2039 : * to pull up into the parent query.
2040 : *
2041 : * rte is the RTE_VALUES RangeTblEntry to check.
2042 : */
2043 : static bool
2044 12734 : is_simple_values(PlannerInfo *root, RangeTblEntry *rte)
2045 : {
2046 : Assert(rte->rtekind == RTE_VALUES);
2047 :
2048 : /*
2049 : * There must be exactly one VALUES list, else it's not semantically
2050 : * correct to replace the VALUES RTE with a RESULT RTE, nor would we have
2051 : * a unique set of expressions to substitute into the parent query.
2052 : */
2053 12734 : if (list_length(rte->values_lists) != 1)
2054 8244 : return false;
2055 :
2056 : /*
2057 : * Because VALUES can't appear under an outer join (or at least, we won't
2058 : * try to pull it up if it does), we need not worry about LATERAL, nor
2059 : * about validity of PHVs for the VALUES' outputs.
2060 : */
2061 :
2062 : /*
2063 : * Don't pull up a VALUES that contains any set-returning or volatile
2064 : * functions. The considerations here are basically identical to the
2065 : * restrictions on a pull-able subquery's targetlist.
2066 : */
2067 8980 : if (expression_returns_set((Node *) rte->values_lists) ||
2068 4490 : contain_volatile_functions((Node *) rte->values_lists))
2069 0 : return false;
2070 :
2071 : /*
2072 : * Do not pull up a VALUES that's not the only RTE in its parent query.
2073 : * This is actually the only case that the parser will generate at the
2074 : * moment, and assuming this is true greatly simplifies
2075 : * pull_up_simple_values().
2076 : */
2077 4490 : if (list_length(root->parse->rtable) != 1 ||
2078 4490 : rte != (RangeTblEntry *) linitial(root->parse->rtable))
2079 0 : return false;
2080 :
2081 4490 : return true;
2082 : }
2083 :
2084 : /*
2085 : * pull_up_constant_function
2086 : * Pull up an RTE_FUNCTION expression that was simplified to a constant.
2087 : *
2088 : * jtnode is a RangeTblRef that has been identified as a FUNCTION RTE by
2089 : * pull_up_subqueries. If its expression is just a Const, hoist that value
2090 : * up into the parent query, and replace the RTE_FUNCTION with RTE_RESULT.
2091 : *
2092 : * In principle we could pull up any immutable expression, but we don't.
2093 : * That might result in multiple evaluations of the expression, which could
2094 : * be costly if it's not just a Const. Also, the main value of this is
2095 : * to let the constant participate in further const-folding, and of course
2096 : * that won't happen for a non-Const.
2097 : *
2098 : * The pulled-up value might need to be wrapped in a PlaceHolderVar if the
2099 : * RTE is below an outer join or is part of an appendrel; the extra
2100 : * parameters show whether that's needed.
2101 : */
2102 : static Node *
2103 55444 : pull_up_constant_function(PlannerInfo *root, Node *jtnode,
2104 : RangeTblEntry *rte,
2105 : AppendRelInfo *containing_appendrel)
2106 : {
2107 55444 : Query *parse = root->parse;
2108 : RangeTblFunction *rtf;
2109 : TypeFuncClass functypclass;
2110 : Oid funcrettype;
2111 : TupleDesc tupdesc;
2112 : pullup_replace_vars_context rvcontext;
2113 :
2114 : /* Fail if the RTE has ORDINALITY - we don't implement that here. */
2115 55444 : if (rte->funcordinality)
2116 1110 : return jtnode;
2117 :
2118 : /* Fail if RTE isn't a single, simple Const expr */
2119 54334 : if (list_length(rte->functions) != 1)
2120 72 : return jtnode;
2121 54262 : rtf = linitial_node(RangeTblFunction, rte->functions);
2122 54262 : if (!IsA(rtf->funcexpr, Const))
2123 53890 : return jtnode;
2124 :
2125 : /*
2126 : * If the function's result is not a scalar, we punt. In principle we
2127 : * could break the composite constant value apart into per-column
2128 : * constants, but for now it seems not worth the work.
2129 : */
2130 372 : if (rtf->funccolcount != 1)
2131 30 : return jtnode; /* definitely composite */
2132 :
2133 : /* If it has a coldeflist, it certainly returns RECORD */
2134 342 : if (rtf->funccolnames != NIL)
2135 0 : return jtnode; /* must be a one-column RECORD type */
2136 :
2137 342 : functypclass = get_expr_result_type(rtf->funcexpr,
2138 : &funcrettype,
2139 : &tupdesc);
2140 342 : if (functypclass != TYPEFUNC_SCALAR)
2141 12 : return jtnode; /* must be a one-column composite type */
2142 :
2143 : /* Create context for applying pullup_replace_vars */
2144 330 : rvcontext.root = root;
2145 330 : rvcontext.targetlist = list_make1(makeTargetEntry((Expr *) rtf->funcexpr,
2146 : 1, /* resno */
2147 : NULL, /* resname */
2148 : false)); /* resjunk */
2149 330 : rvcontext.target_rte = rte;
2150 330 : rvcontext.result_relation = 0;
2151 :
2152 : /*
2153 : * Since this function was reduced to a Const, it doesn't contain any
2154 : * lateral references, even if it's marked as LATERAL. This means we
2155 : * don't need to fill relids or nullinfo.
2156 : */
2157 330 : rvcontext.relids = NULL;
2158 330 : rvcontext.nullinfo = NULL;
2159 :
2160 330 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2161 330 : rvcontext.varno = ((RangeTblRef *) jtnode)->rtindex;
2162 : /* this flag will be set below, if needed */
2163 330 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2164 : /* initialize cache array with indexes 0 .. length(tlist) */
2165 330 : rvcontext.rv_cache = palloc0((list_length(rvcontext.targetlist) + 1) *
2166 : sizeof(Node *));
2167 :
2168 : /*
2169 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
2170 : * each expression of the subquery's targetlist items. (See comments in
2171 : * pull_up_simple_subquery().)
2172 : */
2173 330 : if (parse->groupingSets)
2174 0 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
2175 :
2176 : /*
2177 : * Replace all of the top query's references to the RTE's output with
2178 : * copies of the funcexpr, being careful not to replace any of the
2179 : * jointree structure.
2180 : */
2181 330 : perform_pullup_replace_vars(root, &rvcontext,
2182 : containing_appendrel);
2183 :
2184 : /*
2185 : * We don't need to bother with changing PlaceHolderVars in the parent
2186 : * query. Their references to the RT index are still good for now, and
2187 : * will get removed later if we're able to drop the RTE_RESULT.
2188 : */
2189 :
2190 : /*
2191 : * Convert the RTE to be RTE_RESULT type, signifying that we don't need to
2192 : * scan it anymore, and zero out RTE_FUNCTION-specific fields. Also make
2193 : * sure the RTE is not marked LATERAL, since elsewhere we don't expect
2194 : * RTE_RESULTs to be LATERAL.
2195 : */
2196 330 : rte->rtekind = RTE_RESULT;
2197 330 : rte->functions = NIL;
2198 330 : rte->lateral = false;
2199 :
2200 : /*
2201 : * We can reuse the RangeTblRef node.
2202 : */
2203 330 : return jtnode;
2204 : }
2205 :
2206 : /*
2207 : * is_simple_union_all
2208 : * Check a subquery to see if it's a simple UNION ALL.
2209 : *
2210 : * We require all the setops to be UNION ALL (no mixing) and there can't be
2211 : * any datatype coercions involved, ie, all the leaf queries must emit the
2212 : * same datatypes.
2213 : */
2214 : static bool
2215 15976 : is_simple_union_all(Query *subquery)
2216 : {
2217 : SetOperationStmt *topop;
2218 :
2219 : /* Let's just make sure it's a valid subselect ... */
2220 15976 : if (!IsA(subquery, Query) ||
2221 15976 : subquery->commandType != CMD_SELECT)
2222 0 : elog(ERROR, "subquery is bogus");
2223 :
2224 : /* Is it a set-operation query at all? */
2225 15976 : topop = castNode(SetOperationStmt, subquery->setOperations);
2226 15976 : if (!topop)
2227 10892 : return false;
2228 :
2229 : /* Can't handle ORDER BY, LIMIT/OFFSET, locking, or WITH */
2230 5084 : if (subquery->sortClause ||
2231 5020 : subquery->limitOffset ||
2232 5020 : subquery->limitCount ||
2233 5020 : subquery->rowMarks ||
2234 5020 : subquery->cteList)
2235 224 : return false;
2236 :
2237 : /* Recursively check the tree of set operations */
2238 4860 : return is_simple_union_all_recurse((Node *) topop, subquery,
2239 : topop->colTypes);
2240 : }
2241 :
2242 : static bool
2243 23738 : is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes)
2244 : {
2245 : /* Since this function recurses, it could be driven to stack overflow. */
2246 23738 : check_stack_depth();
2247 :
2248 23738 : if (IsA(setOp, RangeTblRef))
2249 : {
2250 11886 : RangeTblRef *rtr = (RangeTblRef *) setOp;
2251 11886 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
2252 11886 : Query *subquery = rte->subquery;
2253 :
2254 : Assert(subquery != NULL);
2255 :
2256 : /* Leaf nodes are OK if they match the toplevel column types */
2257 : /* We don't have to compare typmods or collations here */
2258 11886 : return tlist_same_datatypes(subquery->targetList, colTypes, true);
2259 : }
2260 11852 : else if (IsA(setOp, SetOperationStmt))
2261 : {
2262 11852 : SetOperationStmt *op = (SetOperationStmt *) setOp;
2263 :
2264 : /* Must be UNION ALL */
2265 11852 : if (op->op != SETOP_UNION || !op->all)
2266 4818 : return false;
2267 :
2268 : /* Recurse to check inputs */
2269 13286 : return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
2270 6252 : is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
2271 : }
2272 : else
2273 : {
2274 0 : elog(ERROR, "unrecognized node type: %d",
2275 : (int) nodeTag(setOp));
2276 : return false; /* keep compiler quiet */
2277 : }
2278 : }
2279 :
2280 : /*
2281 : * is_safe_append_member
2282 : * Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
2283 : * safe to pull up.
2284 : */
2285 : static bool
2286 13436 : is_safe_append_member(Query *subquery)
2287 : {
2288 : FromExpr *jtnode;
2289 :
2290 : /*
2291 : * It's only safe to pull up the child if its jointree contains exactly
2292 : * one RTE, else the AppendRelInfo data structure breaks. The one base RTE
2293 : * could be buried in several levels of FromExpr, however. Also, if the
2294 : * child's jointree is completely empty, we can pull up because
2295 : * pull_up_simple_subquery will insert a single RTE_RESULT RTE instead.
2296 : *
2297 : * Also, the child can't have any WHERE quals because there's no place to
2298 : * put them in an appendrel. (This is a bit annoying...) If we didn't
2299 : * need to check this, we'd just test whether get_relids_in_jointree()
2300 : * yields a singleton set, to be more consistent with the coding of
2301 : * fix_append_rel_relids().
2302 : */
2303 13436 : jtnode = subquery->jointree;
2304 : Assert(IsA(jtnode, FromExpr));
2305 : /* Check the completely-empty case */
2306 13436 : if (jtnode->fromlist == NIL && jtnode->quals == NULL)
2307 578 : return true;
2308 : /* Check the more general case */
2309 24750 : while (IsA(jtnode, FromExpr))
2310 : {
2311 12870 : if (jtnode->quals != NULL)
2312 978 : return false;
2313 11892 : if (list_length(jtnode->fromlist) != 1)
2314 0 : return false;
2315 11892 : jtnode = linitial(jtnode->fromlist);
2316 : }
2317 11880 : if (!IsA(jtnode, RangeTblRef))
2318 228 : return false;
2319 :
2320 11652 : return true;
2321 : }
2322 :
2323 : /*
2324 : * jointree_contains_lateral_outer_refs
2325 : * Check for disallowed lateral references in a jointree's quals
2326 : *
2327 : * If restricted is false, all level-1 Vars are allowed (but we still must
2328 : * search the jointree, since it might contain outer joins below which there
2329 : * will be restrictions). If restricted is true, return true when any qual
2330 : * in the jointree contains level-1 Vars coming from outside the rels listed
2331 : * in safe_upper_varnos.
2332 : */
2333 : static bool
2334 5076 : jointree_contains_lateral_outer_refs(PlannerInfo *root, Node *jtnode,
2335 : bool restricted,
2336 : Relids safe_upper_varnos)
2337 : {
2338 5076 : if (jtnode == NULL)
2339 0 : return false;
2340 5076 : if (IsA(jtnode, RangeTblRef))
2341 2360 : return false;
2342 2716 : else if (IsA(jtnode, FromExpr))
2343 : {
2344 2408 : FromExpr *f = (FromExpr *) jtnode;
2345 : ListCell *l;
2346 :
2347 : /* First, recurse to check child joins */
2348 4478 : foreach(l, f->fromlist)
2349 : {
2350 2094 : if (jointree_contains_lateral_outer_refs(root,
2351 2094 : lfirst(l),
2352 : restricted,
2353 : safe_upper_varnos))
2354 24 : return true;
2355 : }
2356 :
2357 : /* Then check the top-level quals */
2358 2384 : if (restricted &&
2359 1378 : !bms_is_subset(pull_varnos_of_level(root, f->quals, 1),
2360 : safe_upper_varnos))
2361 0 : return true;
2362 : }
2363 308 : else if (IsA(jtnode, JoinExpr))
2364 : {
2365 308 : JoinExpr *j = (JoinExpr *) jtnode;
2366 :
2367 : /*
2368 : * If this is an outer join, we mustn't allow any upper lateral
2369 : * references in or below it.
2370 : */
2371 308 : if (j->jointype != JOIN_INNER)
2372 : {
2373 152 : restricted = true;
2374 152 : safe_upper_varnos = NULL;
2375 : }
2376 :
2377 : /* Check the child joins */
2378 308 : if (jointree_contains_lateral_outer_refs(root,
2379 : j->larg,
2380 : restricted,
2381 : safe_upper_varnos))
2382 0 : return true;
2383 308 : if (jointree_contains_lateral_outer_refs(root,
2384 : j->rarg,
2385 : restricted,
2386 : safe_upper_varnos))
2387 0 : return true;
2388 :
2389 : /* Check the JOIN's qual clauses */
2390 308 : if (restricted &&
2391 284 : !bms_is_subset(pull_varnos_of_level(root, j->quals, 1),
2392 : safe_upper_varnos))
2393 24 : return true;
2394 : }
2395 : else
2396 0 : elog(ERROR, "unrecognized node type: %d",
2397 : (int) nodeTag(jtnode));
2398 2668 : return false;
2399 : }
2400 :
2401 : /*
2402 : * Perform pullup_replace_vars everyplace it's needed in the query tree.
2403 : *
2404 : * Caller has already filled *rvcontext with data describing what to
2405 : * substitute for Vars referencing the target subquery. In addition
2406 : * we need the identity of the containing appendrel if any.
2407 : */
2408 : static void
2409 41232 : perform_pullup_replace_vars(PlannerInfo *root,
2410 : pullup_replace_vars_context *rvcontext,
2411 : AppendRelInfo *containing_appendrel)
2412 : {
2413 41232 : Query *parse = root->parse;
2414 : ListCell *lc;
2415 :
2416 : /*
2417 : * If we are considering an appendrel child subquery (that is, a UNION ALL
2418 : * member query that we're pulling up), then the only part of the upper
2419 : * query that could reference the child yet is the translated_vars list of
2420 : * the associated AppendRelInfo. Furthermore, we do not want to force use
2421 : * of PHVs in the AppendRelInfo --- there isn't any outer join between.
2422 : */
2423 41232 : if (containing_appendrel)
2424 : {
2425 6020 : ReplaceWrapOption save_wrap_option = rvcontext->wrap_option;
2426 :
2427 6020 : rvcontext->wrap_option = REPLACE_WRAP_NONE;
2428 6020 : containing_appendrel->translated_vars = (List *)
2429 6020 : pullup_replace_vars((Node *) containing_appendrel->translated_vars,
2430 : rvcontext);
2431 6020 : rvcontext->wrap_option = save_wrap_option;
2432 6020 : return;
2433 : }
2434 :
2435 : /*
2436 : * Replace all of the top query's references to the subquery's outputs
2437 : * with copies of the adjusted subtlist items, being careful not to
2438 : * replace any of the jointree structure. (This'd be a lot cleaner if we
2439 : * could use query_tree_mutator.) We have to use PHVs in the targetList,
2440 : * returningList, and havingQual, since those are certainly above any
2441 : * outer join. replace_vars_in_jointree tracks its location in the
2442 : * jointree and uses PHVs or not appropriately.
2443 : */
2444 35212 : parse->targetList = (List *)
2445 35212 : pullup_replace_vars((Node *) parse->targetList, rvcontext);
2446 35212 : parse->returningList = (List *)
2447 35212 : pullup_replace_vars((Node *) parse->returningList, rvcontext);
2448 :
2449 35212 : if (parse->onConflict)
2450 : {
2451 44 : parse->onConflict->onConflictSet = (List *)
2452 22 : pullup_replace_vars((Node *) parse->onConflict->onConflictSet,
2453 : rvcontext);
2454 22 : parse->onConflict->onConflictWhere =
2455 22 : pullup_replace_vars(parse->onConflict->onConflictWhere,
2456 : rvcontext);
2457 :
2458 : /*
2459 : * We assume ON CONFLICT's arbiterElems, arbiterWhere, exclRelTlist
2460 : * can't contain any references to a subquery.
2461 : */
2462 : }
2463 35212 : if (parse->mergeActionList)
2464 : {
2465 2888 : foreach(lc, parse->mergeActionList)
2466 : {
2467 1718 : MergeAction *action = lfirst(lc);
2468 :
2469 1718 : action->qual = pullup_replace_vars(action->qual, rvcontext);
2470 1718 : action->targetList = (List *)
2471 1718 : pullup_replace_vars((Node *) action->targetList, rvcontext);
2472 : }
2473 : }
2474 35212 : parse->mergeJoinCondition = pullup_replace_vars(parse->mergeJoinCondition,
2475 : rvcontext);
2476 35212 : replace_vars_in_jointree((Node *) parse->jointree, rvcontext);
2477 : Assert(parse->setOperations == NULL);
2478 35206 : parse->havingQual = pullup_replace_vars(parse->havingQual, rvcontext);
2479 :
2480 : /*
2481 : * Replace references in the translated_vars lists of appendrels.
2482 : */
2483 35218 : foreach(lc, root->append_rel_list)
2484 : {
2485 12 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(lc);
2486 :
2487 12 : appinfo->translated_vars = (List *)
2488 12 : pullup_replace_vars((Node *) appinfo->translated_vars, rvcontext);
2489 : }
2490 :
2491 : /*
2492 : * Replace references in the joinaliasvars lists of join RTEs and the
2493 : * groupexprs list of group RTE.
2494 : */
2495 97954 : foreach(lc, parse->rtable)
2496 : {
2497 62748 : RangeTblEntry *otherrte = (RangeTblEntry *) lfirst(lc);
2498 :
2499 62748 : if (otherrte->rtekind == RTE_JOIN)
2500 6514 : otherrte->joinaliasvars = (List *)
2501 6514 : pullup_replace_vars((Node *) otherrte->joinaliasvars,
2502 : rvcontext);
2503 56234 : else if (otherrte->rtekind == RTE_GROUP)
2504 736 : otherrte->groupexprs = (List *)
2505 736 : pullup_replace_vars((Node *) otherrte->groupexprs,
2506 : rvcontext);
2507 : }
2508 : }
2509 :
2510 : /*
2511 : * Helper routine for perform_pullup_replace_vars: do pullup_replace_vars on
2512 : * every expression in the jointree, without changing the jointree structure
2513 : * itself. Ugly, but there's no other way...
2514 : */
2515 : static void
2516 91392 : replace_vars_in_jointree(Node *jtnode,
2517 : pullup_replace_vars_context *context)
2518 : {
2519 91392 : if (jtnode == NULL)
2520 0 : return;
2521 91392 : if (IsA(jtnode, RangeTblRef))
2522 : {
2523 : /*
2524 : * If the RangeTblRef refers to a LATERAL subquery (that isn't the
2525 : * same subquery we're pulling up), it might contain references to the
2526 : * target subquery, which we must replace. We drive this from the
2527 : * jointree scan, rather than a scan of the rtable, so that we can
2528 : * avoid processing no-longer-referenced RTEs.
2529 : */
2530 45922 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2531 :
2532 45922 : if (varno != context->varno) /* ignore target subquery itself */
2533 : {
2534 10710 : RangeTblEntry *rte = rt_fetch(varno, context->root->parse->rtable);
2535 :
2536 : Assert(rte != context->target_rte);
2537 10710 : if (rte->lateral)
2538 : {
2539 866 : switch (rte->rtekind)
2540 : {
2541 0 : case RTE_RELATION:
2542 : /* shouldn't be marked LATERAL unless tablesample */
2543 : Assert(rte->tablesample);
2544 0 : rte->tablesample = (TableSampleClause *)
2545 0 : pullup_replace_vars((Node *) rte->tablesample,
2546 : context);
2547 0 : break;
2548 408 : case RTE_SUBQUERY:
2549 408 : rte->subquery =
2550 408 : pullup_replace_vars_subquery(rte->subquery,
2551 : context);
2552 408 : break;
2553 350 : case RTE_FUNCTION:
2554 350 : rte->functions = (List *)
2555 350 : pullup_replace_vars((Node *) rte->functions,
2556 : context);
2557 350 : break;
2558 108 : case RTE_TABLEFUNC:
2559 108 : rte->tablefunc = (TableFunc *)
2560 108 : pullup_replace_vars((Node *) rte->tablefunc,
2561 : context);
2562 108 : break;
2563 0 : case RTE_VALUES:
2564 0 : rte->values_lists = (List *)
2565 0 : pullup_replace_vars((Node *) rte->values_lists,
2566 : context);
2567 0 : break;
2568 0 : case RTE_JOIN:
2569 : case RTE_CTE:
2570 : case RTE_NAMEDTUPLESTORE:
2571 : case RTE_RESULT:
2572 : case RTE_GROUP:
2573 : /* these shouldn't be marked LATERAL */
2574 : Assert(false);
2575 0 : break;
2576 : }
2577 45922 : }
2578 : }
2579 : }
2580 45470 : else if (IsA(jtnode, FromExpr))
2581 : {
2582 37802 : FromExpr *f = (FromExpr *) jtnode;
2583 : ListCell *l;
2584 :
2585 78646 : foreach(l, f->fromlist)
2586 40844 : replace_vars_in_jointree(lfirst(l), context);
2587 37802 : f->quals = pullup_replace_vars(f->quals, context);
2588 : }
2589 7668 : else if (IsA(jtnode, JoinExpr))
2590 : {
2591 7668 : JoinExpr *j = (JoinExpr *) jtnode;
2592 7668 : ReplaceWrapOption save_wrap_option = context->wrap_option;
2593 :
2594 7668 : replace_vars_in_jointree(j->larg, context);
2595 7668 : replace_vars_in_jointree(j->rarg, context);
2596 :
2597 : /*
2598 : * Use PHVs within the join quals of a full join for variable-free
2599 : * expressions. Otherwise, we cannot identify which side of the join
2600 : * a pulled-up variable-free expression came from, which can lead to
2601 : * failure to make a plan at all because none of the quals appear to
2602 : * be mergeable or hashable conditions.
2603 : */
2604 7668 : if (j->jointype == JOIN_FULL)
2605 622 : context->wrap_option = REPLACE_WRAP_VARFREE;
2606 :
2607 7668 : j->quals = pullup_replace_vars(j->quals, context);
2608 :
2609 7668 : context->wrap_option = save_wrap_option;
2610 : }
2611 : else
2612 0 : elog(ERROR, "unrecognized node type: %d",
2613 : (int) nodeTag(jtnode));
2614 : }
2615 :
2616 : /*
2617 : * Apply pullup variable replacement throughout an expression tree
2618 : *
2619 : * Returns a modified copy of the tree, so this can't be used where we
2620 : * need to do in-place replacement.
2621 : */
2622 : static Node *
2623 204590 : pullup_replace_vars(Node *expr, pullup_replace_vars_context *context)
2624 : {
2625 204590 : return replace_rte_variables(expr,
2626 : context->varno, 0,
2627 : pullup_replace_vars_callback,
2628 : context,
2629 : context->outer_hasSubLinks);
2630 : }
2631 :
2632 : static Node *
2633 113452 : pullup_replace_vars_callback(Var *var,
2634 : replace_rte_variables_context *context)
2635 : {
2636 113452 : pullup_replace_vars_context *rcon = (pullup_replace_vars_context *) context->callback_arg;
2637 113452 : int varattno = var->varattno;
2638 : bool need_phv;
2639 : Node *newnode;
2640 :
2641 : /* System columns are not replaced. */
2642 113452 : if (varattno < InvalidAttrNumber)
2643 42 : return (Node *) copyObject(var);
2644 :
2645 : /*
2646 : * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
2647 : * varnullingrels (unless we find below that the replacement expression is
2648 : * a Var or PlaceHolderVar that we can just add the nullingrels to). We
2649 : * also need one if the caller has instructed us that certain expression
2650 : * replacements need to be wrapped for identification purposes.
2651 : */
2652 215352 : need_phv = (var->varnullingrels != NULL) ||
2653 101942 : (rcon->wrap_option != REPLACE_WRAP_NONE);
2654 :
2655 : /*
2656 : * If PlaceHolderVars are needed, we cache the modified expressions in
2657 : * rcon->rv_cache[]. This is not in hopes of any material speed gain
2658 : * within this function, but to avoid generating identical PHVs with
2659 : * different IDs. That would result in duplicate evaluations at runtime,
2660 : * and possibly prevent optimizations that rely on recognizing different
2661 : * references to the same subquery output as being equal(). So it's worth
2662 : * a bit of extra effort to avoid it.
2663 : *
2664 : * The cached items have phlevelsup = 0 and phnullingrels = NULL; we'll
2665 : * copy them and adjust those values for this reference site below.
2666 : */
2667 113410 : if (need_phv &&
2668 13416 : varattno >= InvalidAttrNumber &&
2669 13416 : varattno <= list_length(rcon->targetlist) &&
2670 13416 : rcon->rv_cache[varattno] != NULL)
2671 : {
2672 : /* Just copy the entry and fall through to adjust phlevelsup etc */
2673 2692 : newnode = copyObject(rcon->rv_cache[varattno]);
2674 : }
2675 : else
2676 : {
2677 : /*
2678 : * Generate the replacement expression. This takes care of expanding
2679 : * wholerow references and dealing with non-default varreturningtype.
2680 : */
2681 110718 : newnode = ReplaceVarFromTargetList(var,
2682 : rcon->target_rte,
2683 : rcon->targetlist,
2684 : rcon->result_relation,
2685 : REPLACEVARS_REPORT_ERROR,
2686 : 0);
2687 :
2688 : /* Insert PlaceHolderVar if needed */
2689 110718 : if (need_phv)
2690 : {
2691 : bool wrap;
2692 :
2693 10724 : if (rcon->wrap_option == REPLACE_WRAP_ALL)
2694 : {
2695 : /* Caller told us to wrap all expressions in a PlaceHolderVar */
2696 788 : wrap = true;
2697 : }
2698 9936 : else if (varattno == InvalidAttrNumber)
2699 : {
2700 : /*
2701 : * Insert PlaceHolderVar for whole-tuple reference. Notice
2702 : * that we are wrapping one PlaceHolderVar around the whole
2703 : * RowExpr, rather than putting one around each element of the
2704 : * row. This is because we need the expression to yield NULL,
2705 : * not ROW(NULL,NULL,...) when it is forced to null by an
2706 : * outer join.
2707 : */
2708 66 : wrap = true;
2709 : }
2710 9870 : else if (newnode && IsA(newnode, Var) &&
2711 7914 : ((Var *) newnode)->varlevelsup == 0)
2712 : {
2713 : /*
2714 : * Simple Vars always escape being wrapped, unless they are
2715 : * lateral references to something outside the subquery being
2716 : * pulled up and the referenced rel is not under the same
2717 : * lowest nulling outer join.
2718 : */
2719 7898 : wrap = false;
2720 7898 : if (rcon->target_rte->lateral &&
2721 1410 : !bms_is_member(((Var *) newnode)->varno, rcon->relids))
2722 : {
2723 132 : nullingrel_info *nullinfo = rcon->nullinfo;
2724 132 : int lvarno = ((Var *) newnode)->varno;
2725 :
2726 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2727 132 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2728 132 : nullinfo->nullingrels[lvarno]))
2729 108 : wrap = true;
2730 : }
2731 : }
2732 1972 : else if (newnode && IsA(newnode, PlaceHolderVar) &&
2733 180 : ((PlaceHolderVar *) newnode)->phlevelsup == 0)
2734 : {
2735 : /* The same rules apply for a PlaceHolderVar */
2736 180 : wrap = false;
2737 180 : if (rcon->target_rte->lateral &&
2738 48 : !bms_is_subset(((PlaceHolderVar *) newnode)->phrels,
2739 48 : rcon->relids))
2740 : {
2741 48 : nullingrel_info *nullinfo = rcon->nullinfo;
2742 48 : Relids lvarnos = ((PlaceHolderVar *) newnode)->phrels;
2743 : int lvarno;
2744 :
2745 48 : lvarno = -1;
2746 72 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2747 : {
2748 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2749 48 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2750 48 : nullinfo->nullingrels[lvarno]))
2751 : {
2752 24 : wrap = true;
2753 24 : break;
2754 : }
2755 : }
2756 : }
2757 : }
2758 : else
2759 : {
2760 : /*
2761 : * If the node contains Var(s) or PlaceHolderVar(s) of the
2762 : * subquery being pulled up, or of rels that are under the
2763 : * same lowest nulling outer join as the subquery, and does
2764 : * not contain any non-strict constructs, then instead of
2765 : * adding a PHV on top we can add the required nullingrels to
2766 : * those Vars/PHVs. (This is fundamentally a generalization
2767 : * of the above cases for bare Vars and PHVs.)
2768 : *
2769 : * This test is somewhat expensive, but it avoids pessimizing
2770 : * the plan in cases where the nullingrels get removed again
2771 : * later by outer join reduction.
2772 : *
2773 : * Note that we don't force wrapping of expressions containing
2774 : * lateral references, so long as they also contain Vars/PHVs
2775 : * of the subquery, or of rels that are under the same lowest
2776 : * nulling outer join as the subquery. This is okay because
2777 : * of the restriction to strict constructs: if those Vars/PHVs
2778 : * have been forced to NULL by an outer join then the end
2779 : * result of the expression will be NULL too, regardless of
2780 : * the lateral references. So it's not necessary to force the
2781 : * expression to be evaluated below the outer join. This can
2782 : * be a very valuable optimization, because it may allow us to
2783 : * avoid using a nested loop to pass the lateral reference
2784 : * down.
2785 : *
2786 : * This analysis could be tighter: in particular, a non-strict
2787 : * construct hidden within a lower-level PlaceHolderVar is not
2788 : * reason to add another PHV. But for now it doesn't seem
2789 : * worth the code to be more exact. This is also why it's
2790 : * preferable to handle bare PHVs in the above branch, rather
2791 : * than this branch. We also prefer to handle bare Vars in a
2792 : * separate branch, as it's cheaper this way and parallels the
2793 : * handling of PHVs.
2794 : *
2795 : * For a LATERAL subquery, we have to check the actual var
2796 : * membership of the node, but if it's non-lateral then any
2797 : * level-zero var must belong to the subquery.
2798 : */
2799 1792 : bool contain_nullable_vars = false;
2800 :
2801 1792 : if (!rcon->target_rte->lateral)
2802 : {
2803 1564 : if (contain_vars_of_level(newnode, 0))
2804 510 : contain_nullable_vars = true;
2805 : }
2806 : else
2807 : {
2808 : Relids all_varnos;
2809 :
2810 228 : all_varnos = pull_varnos(rcon->root, newnode);
2811 228 : if (bms_overlap(all_varnos, rcon->relids))
2812 132 : contain_nullable_vars = true;
2813 : else
2814 : {
2815 96 : nullingrel_info *nullinfo = rcon->nullinfo;
2816 : int varno;
2817 :
2818 96 : varno = -1;
2819 180 : while ((varno = bms_next_member(all_varnos, varno)) >= 0)
2820 : {
2821 : Assert(varno > 0 && varno <= nullinfo->rtlength);
2822 108 : if (bms_is_subset(nullinfo->nullingrels[rcon->varno],
2823 108 : nullinfo->nullingrels[varno]))
2824 : {
2825 24 : contain_nullable_vars = true;
2826 24 : break;
2827 : }
2828 : }
2829 : }
2830 : }
2831 :
2832 1792 : if (contain_nullable_vars &&
2833 666 : !contain_nonstrict_functions(newnode))
2834 : {
2835 : /* No wrap needed */
2836 288 : wrap = false;
2837 : }
2838 : else
2839 : {
2840 : /* Else wrap it in a PlaceHolderVar */
2841 1504 : wrap = true;
2842 : }
2843 : }
2844 :
2845 10724 : if (wrap)
2846 : {
2847 : newnode = (Node *)
2848 2490 : make_placeholder_expr(rcon->root,
2849 : (Expr *) newnode,
2850 : bms_make_singleton(rcon->varno));
2851 :
2852 : /*
2853 : * Cache it if possible (ie, if the attno is in range, which
2854 : * it probably always should be).
2855 : */
2856 4980 : if (varattno >= InvalidAttrNumber &&
2857 2490 : varattno <= list_length(rcon->targetlist))
2858 2490 : rcon->rv_cache[varattno] = copyObject(newnode);
2859 : }
2860 : }
2861 : }
2862 :
2863 : /* Propagate any varnullingrels into the replacement expression */
2864 113410 : if (var->varnullingrels != NULL)
2865 : {
2866 11468 : if (IsA(newnode, Var))
2867 : {
2868 7300 : Var *newvar = (Var *) newnode;
2869 :
2870 : Assert(newvar->varlevelsup == 0);
2871 7300 : newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
2872 7300 : var->varnullingrels);
2873 : }
2874 4168 : else if (IsA(newnode, PlaceHolderVar))
2875 : {
2876 3880 : PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
2877 :
2878 : Assert(newphv->phlevelsup == 0);
2879 3880 : newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
2880 3880 : var->varnullingrels);
2881 : }
2882 : else
2883 : {
2884 : /*
2885 : * There should be Vars/PHVs within the expression that we can
2886 : * modify. Vars/PHVs of the subquery should have the full
2887 : * var->varnullingrels added to them, but if there are lateral
2888 : * references within the expression, those must be marked with
2889 : * only the nullingrels that potentially apply to them. (This
2890 : * corresponds to the fact that the expression will now be
2891 : * evaluated at the join level of the Var that we are replacing:
2892 : * the lateral references may have bubbled up through fewer outer
2893 : * joins than the subquery's Vars have. Per the discussion above,
2894 : * we'll still get the right answers.) That relid set could be
2895 : * different for different lateral relations, so we have to do
2896 : * this work for each one.
2897 : *
2898 : * (Currently, the restrictions in is_simple_subquery() mean that
2899 : * at most we have to remove the lowest outer join's relid from
2900 : * the nullingrels of a lateral reference. However, we might
2901 : * relax those restrictions someday, so let's do this right.)
2902 : */
2903 288 : if (rcon->target_rte->lateral)
2904 : {
2905 84 : nullingrel_info *nullinfo = rcon->nullinfo;
2906 : Relids lvarnos;
2907 : int lvarno;
2908 :
2909 : /*
2910 : * Identify lateral varnos used within newnode. We must do
2911 : * this before injecting var->varnullingrels into the tree.
2912 : */
2913 84 : lvarnos = pull_varnos(rcon->root, newnode);
2914 84 : lvarnos = bms_del_members(lvarnos, rcon->relids);
2915 : /* For each one, add relevant nullingrels if any */
2916 84 : lvarno = -1;
2917 168 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2918 : {
2919 : Relids lnullingrels;
2920 :
2921 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2922 84 : lnullingrels = bms_intersect(var->varnullingrels,
2923 84 : nullinfo->nullingrels[lvarno]);
2924 84 : if (!bms_is_empty(lnullingrels))
2925 48 : newnode = add_nulling_relids(newnode,
2926 48 : bms_make_singleton(lvarno),
2927 : lnullingrels);
2928 : }
2929 : }
2930 :
2931 : /* Finally, deal with Vars/PHVs of the subquery itself */
2932 288 : newnode = add_nulling_relids(newnode,
2933 288 : rcon->relids,
2934 288 : var->varnullingrels);
2935 : /* Assert we did put the varnullingrels into the expression */
2936 : Assert(bms_is_subset(var->varnullingrels,
2937 : pull_varnos(rcon->root, newnode)));
2938 : }
2939 : }
2940 :
2941 : /* Must adjust varlevelsup if replaced Var is within a subquery */
2942 113410 : if (var->varlevelsup > 0)
2943 1172 : IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
2944 :
2945 113410 : return newnode;
2946 : }
2947 :
2948 : /*
2949 : * Apply pullup variable replacement to a subquery
2950 : *
2951 : * This needs to be different from pullup_replace_vars() because
2952 : * replace_rte_variables will think that it shouldn't increment sublevels_up
2953 : * before entering the Query; so we need to call it with sublevels_up == 1.
2954 : */
2955 : static Query *
2956 408 : pullup_replace_vars_subquery(Query *query,
2957 : pullup_replace_vars_context *context)
2958 : {
2959 : Assert(IsA(query, Query));
2960 408 : return (Query *) replace_rte_variables((Node *) query,
2961 : context->varno, 1,
2962 : pullup_replace_vars_callback,
2963 : context,
2964 : NULL);
2965 : }
2966 :
2967 :
2968 : /*
2969 : * flatten_simple_union_all
2970 : * Try to optimize top-level UNION ALL structure into an appendrel
2971 : *
2972 : * If a query's setOperations tree consists entirely of simple UNION ALL
2973 : * operations, flatten it into an append relation, which we can process more
2974 : * intelligently than the general setops case. Otherwise, do nothing.
2975 : *
2976 : * In most cases, this can succeed only for a top-level query, because for a
2977 : * subquery in FROM, the parent query's invocation of pull_up_subqueries would
2978 : * already have flattened the UNION via pull_up_simple_union_all. But there
2979 : * are a few cases we can support here but not in that code path, for example
2980 : * when the subquery also contains ORDER BY.
2981 : */
2982 : void
2983 6602 : flatten_simple_union_all(PlannerInfo *root)
2984 : {
2985 6602 : Query *parse = root->parse;
2986 : SetOperationStmt *topop;
2987 : Node *leftmostjtnode;
2988 : int leftmostRTI;
2989 : RangeTblEntry *leftmostRTE;
2990 : int childRTI;
2991 : RangeTblEntry *childRTE;
2992 : RangeTblRef *rtr;
2993 :
2994 : /* Shouldn't be called unless query has setops */
2995 6602 : topop = castNode(SetOperationStmt, parse->setOperations);
2996 : Assert(topop);
2997 :
2998 : /* Can't optimize away a recursive UNION */
2999 6602 : if (root->hasRecursion)
3000 6166 : return;
3001 :
3002 : /*
3003 : * Recursively check the tree of set operations. If not all UNION ALL
3004 : * with identical column types, punt.
3005 : */
3006 5592 : if (!is_simple_union_all_recurse((Node *) topop, parse, topop->colTypes))
3007 5156 : return;
3008 :
3009 : /*
3010 : * Locate the leftmost leaf query in the setops tree. The upper query's
3011 : * Vars all refer to this RTE (see transformSetOperationStmt).
3012 : */
3013 436 : leftmostjtnode = topop->larg;
3014 780 : while (leftmostjtnode && IsA(leftmostjtnode, SetOperationStmt))
3015 344 : leftmostjtnode = ((SetOperationStmt *) leftmostjtnode)->larg;
3016 : Assert(leftmostjtnode && IsA(leftmostjtnode, RangeTblRef));
3017 436 : leftmostRTI = ((RangeTblRef *) leftmostjtnode)->rtindex;
3018 436 : leftmostRTE = rt_fetch(leftmostRTI, parse->rtable);
3019 : Assert(leftmostRTE->rtekind == RTE_SUBQUERY);
3020 :
3021 : /*
3022 : * Make a copy of the leftmost RTE and add it to the rtable. This copy
3023 : * will represent the leftmost leaf query in its capacity as a member of
3024 : * the appendrel. The original will represent the appendrel as a whole.
3025 : * (We must do things this way because the upper query's Vars have to be
3026 : * seen as referring to the whole appendrel.)
3027 : */
3028 436 : childRTE = copyObject(leftmostRTE);
3029 436 : parse->rtable = lappend(parse->rtable, childRTE);
3030 436 : childRTI = list_length(parse->rtable);
3031 :
3032 : /* Modify the setops tree to reference the child copy */
3033 436 : ((RangeTblRef *) leftmostjtnode)->rtindex = childRTI;
3034 :
3035 : /* Modify the formerly-leftmost RTE to mark it as an appendrel parent */
3036 436 : leftmostRTE->inh = true;
3037 :
3038 : /*
3039 : * Form a RangeTblRef for the appendrel, and insert it into FROM. The top
3040 : * Query of a setops tree should have had an empty FromClause initially.
3041 : */
3042 436 : rtr = makeNode(RangeTblRef);
3043 436 : rtr->rtindex = leftmostRTI;
3044 : Assert(parse->jointree->fromlist == NIL);
3045 436 : parse->jointree->fromlist = list_make1(rtr);
3046 :
3047 : /*
3048 : * Now pretend the query has no setops. We must do this before trying to
3049 : * do subquery pullup, because of Assert in pull_up_simple_subquery.
3050 : */
3051 436 : parse->setOperations = NULL;
3052 :
3053 : /*
3054 : * Build AppendRelInfo information, and apply pull_up_subqueries to the
3055 : * leaf queries of the UNION ALL. (We must do that now because they
3056 : * weren't previously referenced by the jointree, and so were missed by
3057 : * the main invocation of pull_up_subqueries.)
3058 : */
3059 436 : pull_up_union_leaf_queries((Node *) topop, root, leftmostRTI, parse, 0);
3060 : }
3061 :
3062 :
3063 : /*
3064 : * reduce_outer_joins
3065 : * Attempt to reduce outer joins to plain inner joins.
3066 : *
3067 : * The idea here is that given a query like
3068 : * SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
3069 : * we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
3070 : * is strict. The strict operator will always return NULL, causing the outer
3071 : * WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
3072 : * columns. Therefore, there's no need for the join to produce null-extended
3073 : * rows in the first place --- which makes it a plain join not an outer join.
3074 : * (This scenario may not be very likely in a query written out by hand, but
3075 : * it's reasonably likely when pushing quals down into complex views.)
3076 : *
3077 : * More generally, an outer join can be reduced in strength if there is a
3078 : * strict qual above it in the qual tree that constrains a Var from the
3079 : * nullable side of the join to be non-null. (For FULL joins this applies
3080 : * to each side separately.)
3081 : *
3082 : * Another transformation we apply here is to recognize cases like
3083 : * SELECT ... FROM a LEFT JOIN b ON (a.x = b.y) WHERE b.y IS NULL;
3084 : * If the join clause is strict for b.y, then only null-extended rows could
3085 : * pass the upper WHERE, and we can conclude that what the query is really
3086 : * specifying is an anti-semijoin. We change the join type from JOIN_LEFT
3087 : * to JOIN_ANTI. The IS NULL clause then becomes redundant, and must be
3088 : * removed to prevent bogus selectivity calculations, but we leave it to
3089 : * distribute_qual_to_rels to get rid of such clauses.
3090 : *
3091 : * Also, we get rid of JOIN_RIGHT cases by flipping them around to become
3092 : * JOIN_LEFT. This saves some code here and in some later planner routines;
3093 : * the main benefit is to reduce the number of jointypes that can appear in
3094 : * SpecialJoinInfo nodes. Note that we can still generate Paths and Plans
3095 : * that use JOIN_RIGHT (or JOIN_RIGHT_ANTI) by switching the inputs again.
3096 : *
3097 : * To ease recognition of strict qual clauses, we require this routine to be
3098 : * run after expression preprocessing (i.e., qual canonicalization and JOIN
3099 : * alias-var expansion).
3100 : */
3101 : void
3102 34676 : reduce_outer_joins(PlannerInfo *root)
3103 : {
3104 : reduce_outer_joins_pass1_state *state1;
3105 : reduce_outer_joins_pass2_state state2;
3106 : ListCell *lc;
3107 :
3108 : /*
3109 : * To avoid doing strictness checks on more quals than necessary, we want
3110 : * to stop descending the jointree as soon as there are no outer joins
3111 : * below our current point. This consideration forces a two-pass process.
3112 : * The first pass gathers information about which base rels appear below
3113 : * each side of each join clause, and about whether there are outer
3114 : * join(s) below each side of each join clause. The second pass examines
3115 : * qual clauses and changes join types as it descends the tree.
3116 : */
3117 34676 : state1 = reduce_outer_joins_pass1((Node *) root->parse->jointree);
3118 :
3119 : /* planner.c shouldn't have called me if no outer joins */
3120 34676 : if (state1 == NULL || !state1->contains_outer)
3121 0 : elog(ERROR, "so where are the outer joins?");
3122 :
3123 34676 : state2.inner_reduced = NULL;
3124 34676 : state2.partial_reduced = NIL;
3125 :
3126 34676 : reduce_outer_joins_pass2((Node *) root->parse->jointree,
3127 : state1, &state2,
3128 : root, NULL, NIL);
3129 :
3130 : /*
3131 : * If we successfully reduced the strength of any outer joins, we must
3132 : * remove references to those joins as nulling rels. This is handled as
3133 : * an additional pass, for simplicity and because we can handle all
3134 : * fully-reduced joins in a single pass over the parse tree.
3135 : */
3136 34676 : if (!bms_is_empty(state2.inner_reduced))
3137 : {
3138 1818 : root->parse = (Query *)
3139 1818 : remove_nulling_relids((Node *) root->parse,
3140 1818 : state2.inner_reduced,
3141 : NULL);
3142 : /* There could be references in the append_rel_list, too */
3143 1818 : root->append_rel_list = (List *)
3144 1818 : remove_nulling_relids((Node *) root->append_rel_list,
3145 1818 : state2.inner_reduced,
3146 : NULL);
3147 : }
3148 :
3149 : /*
3150 : * Partially-reduced full joins have to be done one at a time, since
3151 : * they'll each need a different setting of except_relids.
3152 : */
3153 34726 : foreach(lc, state2.partial_reduced)
3154 : {
3155 50 : reduce_outer_joins_partial_state *statep = lfirst(lc);
3156 50 : Relids full_join_relids = bms_make_singleton(statep->full_join_rti);
3157 :
3158 50 : root->parse = (Query *)
3159 50 : remove_nulling_relids((Node *) root->parse,
3160 : full_join_relids,
3161 50 : statep->unreduced_side);
3162 50 : root->append_rel_list = (List *)
3163 50 : remove_nulling_relids((Node *) root->append_rel_list,
3164 : full_join_relids,
3165 50 : statep->unreduced_side);
3166 : }
3167 34676 : }
3168 :
3169 : /*
3170 : * reduce_outer_joins_pass1 - phase 1 data collection
3171 : *
3172 : * Returns a state node describing the given jointree node.
3173 : */
3174 : static reduce_outer_joins_pass1_state *
3175 197484 : reduce_outer_joins_pass1(Node *jtnode)
3176 : {
3177 : reduce_outer_joins_pass1_state *result;
3178 :
3179 : result = (reduce_outer_joins_pass1_state *)
3180 197484 : palloc(sizeof(reduce_outer_joins_pass1_state));
3181 197484 : result->relids = NULL;
3182 197484 : result->contains_outer = false;
3183 197484 : result->sub_states = NIL;
3184 :
3185 197484 : if (jtnode == NULL)
3186 0 : return result;
3187 197484 : if (IsA(jtnode, RangeTblRef))
3188 : {
3189 98558 : int varno = ((RangeTblRef *) jtnode)->rtindex;
3190 :
3191 98558 : result->relids = bms_make_singleton(varno);
3192 : }
3193 98926 : else if (IsA(jtnode, FromExpr))
3194 : {
3195 37890 : FromExpr *f = (FromExpr *) jtnode;
3196 : ListCell *l;
3197 :
3198 78626 : foreach(l, f->fromlist)
3199 : {
3200 : reduce_outer_joins_pass1_state *sub_state;
3201 :
3202 40736 : sub_state = reduce_outer_joins_pass1(lfirst(l));
3203 81472 : result->relids = bms_add_members(result->relids,
3204 40736 : sub_state->relids);
3205 40736 : result->contains_outer |= sub_state->contains_outer;
3206 40736 : result->sub_states = lappend(result->sub_states, sub_state);
3207 : }
3208 : }
3209 61036 : else if (IsA(jtnode, JoinExpr))
3210 : {
3211 61036 : JoinExpr *j = (JoinExpr *) jtnode;
3212 : reduce_outer_joins_pass1_state *sub_state;
3213 :
3214 : /* join's own RT index is not wanted in result->relids */
3215 61036 : if (IS_OUTER_JOIN(j->jointype))
3216 49496 : result->contains_outer = true;
3217 :
3218 61036 : sub_state = reduce_outer_joins_pass1(j->larg);
3219 122072 : result->relids = bms_add_members(result->relids,
3220 61036 : sub_state->relids);
3221 61036 : result->contains_outer |= sub_state->contains_outer;
3222 61036 : result->sub_states = lappend(result->sub_states, sub_state);
3223 :
3224 61036 : sub_state = reduce_outer_joins_pass1(j->rarg);
3225 122072 : result->relids = bms_add_members(result->relids,
3226 61036 : sub_state->relids);
3227 61036 : result->contains_outer |= sub_state->contains_outer;
3228 61036 : result->sub_states = lappend(result->sub_states, sub_state);
3229 : }
3230 : else
3231 0 : elog(ERROR, "unrecognized node type: %d",
3232 : (int) nodeTag(jtnode));
3233 197484 : return result;
3234 : }
3235 :
3236 : /*
3237 : * reduce_outer_joins_pass2 - phase 2 processing
3238 : *
3239 : * jtnode: current jointree node
3240 : * state1: state data collected by phase 1 for this node
3241 : * state2: where to accumulate info about successfully-reduced joins
3242 : * root: toplevel planner state
3243 : * nonnullable_rels: set of base relids forced non-null by upper quals
3244 : * forced_null_vars: multibitmapset of Vars forced null by upper quals
3245 : *
3246 : * Returns info in state2 about outer joins that were successfully simplified.
3247 : * Joins that were fully reduced to inner joins are all added to
3248 : * state2->inner_reduced. If a full join is reduced to a left join,
3249 : * it needs its own entry in state2->partial_reduced, since that will
3250 : * require custom processing to remove only the correct nullingrel markers.
3251 : */
3252 : static void
3253 86188 : reduce_outer_joins_pass2(Node *jtnode,
3254 : reduce_outer_joins_pass1_state *state1,
3255 : reduce_outer_joins_pass2_state *state2,
3256 : PlannerInfo *root,
3257 : Relids nonnullable_rels,
3258 : List *forced_null_vars)
3259 : {
3260 : /*
3261 : * pass 2 should never descend as far as an empty subnode or base rel,
3262 : * because it's only called on subtrees marked as contains_outer.
3263 : */
3264 86188 : if (jtnode == NULL)
3265 0 : elog(ERROR, "reached empty jointree");
3266 86188 : if (IsA(jtnode, RangeTblRef))
3267 0 : elog(ERROR, "reached base rel");
3268 86188 : else if (IsA(jtnode, FromExpr))
3269 : {
3270 36112 : FromExpr *f = (FromExpr *) jtnode;
3271 : ListCell *l;
3272 : ListCell *s;
3273 : Relids pass_nonnullable_rels;
3274 : List *pass_forced_null_vars;
3275 :
3276 : /* Scan quals to see if we can add any constraints */
3277 36112 : pass_nonnullable_rels = find_nonnullable_rels(f->quals);
3278 36112 : pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels,
3279 : nonnullable_rels);
3280 36112 : pass_forced_null_vars = find_forced_null_vars(f->quals);
3281 36112 : pass_forced_null_vars = mbms_add_members(pass_forced_null_vars,
3282 : forced_null_vars);
3283 : /* And recurse --- but only into interesting subtrees */
3284 : Assert(list_length(f->fromlist) == list_length(state1->sub_states));
3285 74938 : forboth(l, f->fromlist, s, state1->sub_states)
3286 : {
3287 38826 : reduce_outer_joins_pass1_state *sub_state = lfirst(s);
3288 :
3289 38826 : if (sub_state->contains_outer)
3290 36142 : reduce_outer_joins_pass2(lfirst(l), sub_state,
3291 : state2, root,
3292 : pass_nonnullable_rels,
3293 : pass_forced_null_vars);
3294 : }
3295 36112 : bms_free(pass_nonnullable_rels);
3296 : /* can't so easily clean up var lists, unfortunately */
3297 : }
3298 50076 : else if (IsA(jtnode, JoinExpr))
3299 : {
3300 50076 : JoinExpr *j = (JoinExpr *) jtnode;
3301 50076 : int rtindex = j->rtindex;
3302 50076 : JoinType jointype = j->jointype;
3303 50076 : reduce_outer_joins_pass1_state *left_state = linitial(state1->sub_states);
3304 50076 : reduce_outer_joins_pass1_state *right_state = lsecond(state1->sub_states);
3305 :
3306 : /* Can we simplify this join? */
3307 50076 : switch (jointype)
3308 : {
3309 530 : case JOIN_INNER:
3310 530 : break;
3311 46748 : case JOIN_LEFT:
3312 46748 : if (bms_overlap(nonnullable_rels, right_state->relids))
3313 1894 : jointype = JOIN_INNER;
3314 46748 : break;
3315 1136 : case JOIN_RIGHT:
3316 1136 : if (bms_overlap(nonnullable_rels, left_state->relids))
3317 62 : jointype = JOIN_INNER;
3318 1136 : break;
3319 1090 : case JOIN_FULL:
3320 1090 : if (bms_overlap(nonnullable_rels, left_state->relids))
3321 : {
3322 24 : if (bms_overlap(nonnullable_rels, right_state->relids))
3323 12 : jointype = JOIN_INNER;
3324 : else
3325 : {
3326 12 : jointype = JOIN_LEFT;
3327 : /* Also report partial reduction in state2 */
3328 12 : report_reduced_full_join(state2, rtindex,
3329 : right_state->relids);
3330 : }
3331 : }
3332 : else
3333 : {
3334 1066 : if (bms_overlap(nonnullable_rels, right_state->relids))
3335 : {
3336 38 : jointype = JOIN_RIGHT;
3337 : /* Also report partial reduction in state2 */
3338 38 : report_reduced_full_join(state2, rtindex,
3339 : left_state->relids);
3340 : }
3341 : }
3342 1090 : break;
3343 572 : case JOIN_SEMI:
3344 : case JOIN_ANTI:
3345 :
3346 : /*
3347 : * These could only have been introduced by pull_up_sublinks,
3348 : * so there's no way that upper quals could refer to their
3349 : * righthand sides, and no point in checking. We don't expect
3350 : * to see JOIN_RIGHT_SEMI or JOIN_RIGHT_ANTI yet.
3351 : */
3352 572 : break;
3353 0 : default:
3354 0 : elog(ERROR, "unrecognized join type: %d",
3355 : (int) jointype);
3356 : break;
3357 : }
3358 :
3359 : /*
3360 : * Convert JOIN_RIGHT to JOIN_LEFT. Note that in the case where we
3361 : * reduced JOIN_FULL to JOIN_RIGHT, this will mean the JoinExpr no
3362 : * longer matches the internal ordering of any CoalesceExpr's built to
3363 : * represent merged join variables. We don't care about that at
3364 : * present, but be wary of it ...
3365 : */
3366 50076 : if (jointype == JOIN_RIGHT)
3367 : {
3368 : Node *tmparg;
3369 :
3370 1112 : tmparg = j->larg;
3371 1112 : j->larg = j->rarg;
3372 1112 : j->rarg = tmparg;
3373 1112 : jointype = JOIN_LEFT;
3374 1112 : right_state = linitial(state1->sub_states);
3375 1112 : left_state = lsecond(state1->sub_states);
3376 : }
3377 :
3378 : /*
3379 : * See if we can reduce JOIN_LEFT to JOIN_ANTI. This is the case if
3380 : * the join's own quals are strict for any var that was forced null by
3381 : * higher qual levels. NOTE: there are other ways that we could
3382 : * detect an anti-join, in particular if we were to check whether Vars
3383 : * coming from the RHS must be non-null because of table constraints.
3384 : * That seems complicated and expensive though (in particular, one
3385 : * would have to be wary of lower outer joins). For the moment this
3386 : * seems sufficient.
3387 : */
3388 50076 : if (jointype == JOIN_LEFT)
3389 : {
3390 : List *nonnullable_vars;
3391 : Bitmapset *overlap;
3392 :
3393 : /* Find Vars in j->quals that must be non-null in joined rows */
3394 45978 : nonnullable_vars = find_nonnullable_vars(j->quals);
3395 :
3396 : /*
3397 : * It's not sufficient to check whether nonnullable_vars and
3398 : * forced_null_vars overlap: we need to know if the overlap
3399 : * includes any RHS variables.
3400 : */
3401 45978 : overlap = mbms_overlap_sets(nonnullable_vars, forced_null_vars);
3402 45978 : if (bms_overlap(overlap, right_state->relids))
3403 1180 : jointype = JOIN_ANTI;
3404 : }
3405 :
3406 : /*
3407 : * Apply the jointype change, if any, to both jointree node and RTE.
3408 : * Also, if we changed an RTE to INNER, add its RTI to inner_reduced.
3409 : */
3410 50076 : if (rtindex && jointype != j->jointype)
3411 : {
3412 4272 : RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
3413 :
3414 : Assert(rte->rtekind == RTE_JOIN);
3415 : Assert(rte->jointype == j->jointype);
3416 4272 : rte->jointype = jointype;
3417 4272 : if (jointype == JOIN_INNER)
3418 1968 : state2->inner_reduced = bms_add_member(state2->inner_reduced,
3419 : rtindex);
3420 : }
3421 50076 : j->jointype = jointype;
3422 :
3423 : /* Only recurse if there's more to do below here */
3424 50076 : if (left_state->contains_outer || right_state->contains_outer)
3425 : {
3426 : Relids local_nonnullable_rels;
3427 : List *local_forced_null_vars;
3428 : Relids pass_nonnullable_rels;
3429 : List *pass_forced_null_vars;
3430 :
3431 : /*
3432 : * If this join is (now) inner, we can add any constraints its
3433 : * quals provide to those we got from above. But if it is outer,
3434 : * we can pass down the local constraints only into the nullable
3435 : * side, because an outer join never eliminates any rows from its
3436 : * non-nullable side. Also, there is no point in passing upper
3437 : * constraints into the nullable side, since if there were any
3438 : * we'd have been able to reduce the join. (In the case of upper
3439 : * forced-null constraints, we *must not* pass them into the
3440 : * nullable side --- they either applied here, or not.) The upshot
3441 : * is that we pass either the local or the upper constraints,
3442 : * never both, to the children of an outer join.
3443 : *
3444 : * Note that a SEMI join works like an inner join here: it's okay
3445 : * to pass down both local and upper constraints. (There can't be
3446 : * any upper constraints affecting its inner side, but it's not
3447 : * worth having a separate code path to avoid passing them.)
3448 : *
3449 : * At a FULL join we just punt and pass nothing down --- is it
3450 : * possible to be smarter?
3451 : */
3452 15302 : if (jointype != JOIN_FULL)
3453 : {
3454 15166 : local_nonnullable_rels = find_nonnullable_rels(j->quals);
3455 15166 : local_forced_null_vars = find_forced_null_vars(j->quals);
3456 15166 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3457 : {
3458 : /* OK to merge upper and local constraints */
3459 970 : local_nonnullable_rels = bms_add_members(local_nonnullable_rels,
3460 : nonnullable_rels);
3461 970 : local_forced_null_vars = mbms_add_members(local_forced_null_vars,
3462 : forced_null_vars);
3463 : }
3464 : }
3465 : else
3466 : {
3467 : /* no use in calculating these */
3468 136 : local_nonnullable_rels = NULL;
3469 136 : local_forced_null_vars = NIL;
3470 : }
3471 :
3472 15302 : if (left_state->contains_outer)
3473 : {
3474 14566 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3475 : {
3476 : /* pass union of local and upper constraints */
3477 764 : pass_nonnullable_rels = local_nonnullable_rels;
3478 764 : pass_forced_null_vars = local_forced_null_vars;
3479 : }
3480 13802 : else if (jointype != JOIN_FULL) /* ie, LEFT or ANTI */
3481 : {
3482 : /* can't pass local constraints to non-nullable side */
3483 13694 : pass_nonnullable_rels = nonnullable_rels;
3484 13694 : pass_forced_null_vars = forced_null_vars;
3485 : }
3486 : else
3487 : {
3488 : /* no constraints pass through JOIN_FULL */
3489 108 : pass_nonnullable_rels = NULL;
3490 108 : pass_forced_null_vars = NIL;
3491 : }
3492 14566 : reduce_outer_joins_pass2(j->larg, left_state,
3493 : state2, root,
3494 : pass_nonnullable_rels,
3495 : pass_forced_null_vars);
3496 : }
3497 :
3498 15302 : if (right_state->contains_outer)
3499 : {
3500 804 : if (jointype != JOIN_FULL) /* ie, INNER/LEFT/SEMI/ANTI */
3501 : {
3502 : /* pass appropriate constraints, per comment above */
3503 776 : pass_nonnullable_rels = local_nonnullable_rels;
3504 776 : pass_forced_null_vars = local_forced_null_vars;
3505 : }
3506 : else
3507 : {
3508 : /* no constraints pass through JOIN_FULL */
3509 28 : pass_nonnullable_rels = NULL;
3510 28 : pass_forced_null_vars = NIL;
3511 : }
3512 804 : reduce_outer_joins_pass2(j->rarg, right_state,
3513 : state2, root,
3514 : pass_nonnullable_rels,
3515 : pass_forced_null_vars);
3516 : }
3517 15302 : bms_free(local_nonnullable_rels);
3518 : }
3519 : }
3520 : else
3521 0 : elog(ERROR, "unrecognized node type: %d",
3522 : (int) nodeTag(jtnode));
3523 86188 : }
3524 :
3525 : /* Helper for reduce_outer_joins_pass2 */
3526 : static void
3527 50 : report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
3528 : int rtindex, Relids relids)
3529 : {
3530 : reduce_outer_joins_partial_state *statep;
3531 :
3532 50 : statep = palloc(sizeof(reduce_outer_joins_partial_state));
3533 50 : statep->full_join_rti = rtindex;
3534 50 : statep->unreduced_side = relids;
3535 50 : state2->partial_reduced = lappend(state2->partial_reduced, statep);
3536 50 : }
3537 :
3538 :
3539 : /*
3540 : * remove_useless_result_rtes
3541 : * Attempt to remove RTE_RESULT RTEs from the join tree.
3542 : * Also, elide single-child FromExprs where possible.
3543 : *
3544 : * We can remove RTE_RESULT entries from the join tree using the knowledge
3545 : * that RTE_RESULT returns exactly one row and has no output columns. Hence,
3546 : * if one is inner-joined to anything else, we can delete it. Optimizations
3547 : * are also possible for some outer-join cases, as detailed below.
3548 : *
3549 : * This pass also replaces single-child FromExprs with their child node
3550 : * where possible. It's appropriate to do that here and not earlier because
3551 : * RTE_RESULT removal might reduce a multiple-child FromExpr to have only one
3552 : * child. We can remove such a FromExpr if its quals are empty, or if it's
3553 : * semantically valid to merge the quals into those of the parent node.
3554 : * While removing unnecessary join tree nodes has some micro-efficiency value,
3555 : * the real reason to do this is to eliminate cases where the nullable side of
3556 : * an outer join node is a FromExpr whose single child is another outer join.
3557 : * To correctly determine whether the two outer joins can commute,
3558 : * deconstruct_jointree() must treat any quals of such a FromExpr as being
3559 : * degenerate quals of the upper outer join. The best way to do that is to
3560 : * make them actually *be* quals of the upper join, by dropping the FromExpr
3561 : * and hoisting the quals up into the upper join's quals. (Note that there is
3562 : * no hazard when the intermediate FromExpr has multiple children, since then
3563 : * it represents an inner join that cannot commute with the upper outer join.)
3564 : * As long as we have to do that, we might as well elide such FromExprs
3565 : * everywhere.
3566 : *
3567 : * Some of these optimizations depend on recognizing empty (constant-true)
3568 : * quals for FromExprs and JoinExprs. That makes it useful to apply this
3569 : * optimization pass after expression preprocessing, since that will have
3570 : * eliminated constant-true quals, allowing more cases to be recognized as
3571 : * optimizable. What's more, the usual reason for an RTE_RESULT to be present
3572 : * is that we pulled up a subquery or VALUES clause, thus very possibly
3573 : * replacing Vars with constants, making it more likely that a qual can be
3574 : * reduced to constant true. Also, because some optimizations depend on
3575 : * the outer-join type, it's best to have done reduce_outer_joins() first.
3576 : *
3577 : * A PlaceHolderVar referencing an RTE_RESULT RTE poses an obstacle to this
3578 : * process: we must remove the RTE_RESULT's relid from the PHV's phrels, but
3579 : * we must not reduce the phrels set to empty. If that would happen, and
3580 : * the RTE_RESULT is an immediate child of an outer join, we have to give up
3581 : * and not remove the RTE_RESULT: there is noplace else to evaluate the
3582 : * PlaceHolderVar. (That is, in such cases the RTE_RESULT *does* have output
3583 : * columns.) But if the RTE_RESULT is an immediate child of an inner join,
3584 : * we can usually change the PlaceHolderVar's phrels so as to evaluate it at
3585 : * the inner join instead. This is OK because we really only care that PHVs
3586 : * are evaluated above or below the correct outer joins. We can't, however,
3587 : * postpone the evaluation of a PHV to above where it is used; so there are
3588 : * some checks below on whether output PHVs are laterally referenced in the
3589 : * other join input rel(s).
3590 : *
3591 : * We used to try to do this work as part of pull_up_subqueries() where the
3592 : * potentially-optimizable cases get introduced; but it's way simpler, and
3593 : * more effective, to do it separately.
3594 : */
3595 : void
3596 235432 : remove_useless_result_rtes(PlannerInfo *root)
3597 : {
3598 235432 : Relids dropped_outer_joins = NULL;
3599 : ListCell *cell;
3600 :
3601 : /* Top level of jointree must always be a FromExpr */
3602 : Assert(IsA(root->parse->jointree, FromExpr));
3603 : /* Recurse ... */
3604 470864 : root->parse->jointree = (FromExpr *)
3605 235432 : remove_useless_results_recurse(root,
3606 235432 : (Node *) root->parse->jointree,
3607 : NULL,
3608 : &dropped_outer_joins);
3609 : /* We should still have a FromExpr */
3610 : Assert(IsA(root->parse->jointree, FromExpr));
3611 :
3612 : /*
3613 : * If we removed any outer-join nodes from the jointree, run around and
3614 : * remove references to those joins as nulling rels. (There could be such
3615 : * references in PHVs that we pulled up out of the original subquery that
3616 : * the RESULT rel replaced. This is kosher on the grounds that we now
3617 : * know that such an outer join wouldn't really have nulled anything.) We
3618 : * don't do this during the main recursion, for simplicity and because we
3619 : * can handle all such joins in a single pass over the parse tree.
3620 : */
3621 235432 : if (!bms_is_empty(dropped_outer_joins))
3622 : {
3623 60 : root->parse = (Query *)
3624 60 : remove_nulling_relids((Node *) root->parse,
3625 : dropped_outer_joins,
3626 : NULL);
3627 : /* There could be references in the append_rel_list, too */
3628 60 : root->append_rel_list = (List *)
3629 60 : remove_nulling_relids((Node *) root->append_rel_list,
3630 : dropped_outer_joins,
3631 : NULL);
3632 : }
3633 :
3634 : /*
3635 : * Remove any PlanRowMark referencing an RTE_RESULT RTE. We obviously
3636 : * must do that for any RTE_RESULT that we just removed. But one for a
3637 : * RTE that we did not remove can be dropped anyway: since the RTE has
3638 : * only one possible output row, there is no need for EPQ to mark and
3639 : * restore that row.
3640 : *
3641 : * It's necessary, not optional, to remove the PlanRowMark for a surviving
3642 : * RTE_RESULT RTE; otherwise we'll generate a whole-row Var for the
3643 : * RTE_RESULT, which the executor has no support for.
3644 : */
3645 237458 : foreach(cell, root->rowMarks)
3646 : {
3647 2026 : PlanRowMark *rc = (PlanRowMark *) lfirst(cell);
3648 :
3649 2026 : if (rt_fetch(rc->rti, root->parse->rtable)->rtekind == RTE_RESULT)
3650 906 : root->rowMarks = foreach_delete_current(root->rowMarks, cell);
3651 : }
3652 235432 : }
3653 :
3654 : /*
3655 : * remove_useless_results_recurse
3656 : * Recursive guts of remove_useless_result_rtes.
3657 : *
3658 : * This recursively processes the jointree and returns a modified jointree.
3659 : * In addition, the RT indexes of any removed outer-join nodes are added to
3660 : * *dropped_outer_joins.
3661 : *
3662 : * jtnode is the current jointree node. If it could be valid to merge
3663 : * its quals into those of the parent node, parent_quals should point to
3664 : * the parent's quals list; otherwise, pass NULL for parent_quals.
3665 : * (Note that in some cases, parent_quals points to the quals of a parent
3666 : * more than one level up in the tree.)
3667 : */
3668 : static Node *
3669 610844 : remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
3670 : Node **parent_quals,
3671 : Relids *dropped_outer_joins)
3672 : {
3673 : Assert(jtnode != NULL);
3674 610844 : if (IsA(jtnode, RangeTblRef))
3675 : {
3676 : /* Can't immediately do anything with a RangeTblRef */
3677 : }
3678 307114 : else if (IsA(jtnode, FromExpr))
3679 : {
3680 242308 : FromExpr *f = (FromExpr *) jtnode;
3681 242308 : Relids result_relids = NULL;
3682 : ListCell *cell;
3683 :
3684 : /*
3685 : * We can drop RTE_RESULT rels from the fromlist so long as at least
3686 : * one child remains, since joining to a one-row table changes
3687 : * nothing. (But we can't drop a RTE_RESULT that computes PHV(s) that
3688 : * are needed by some sibling. The cleanup transformation below would
3689 : * reassign the PHVs to be computed at the join, which is too late for
3690 : * the sibling's use.) The easiest way to mechanize this rule is to
3691 : * modify the list in-place.
3692 : */
3693 488108 : foreach(cell, f->fromlist)
3694 : {
3695 245800 : Node *child = (Node *) lfirst(cell);
3696 : int varno;
3697 :
3698 : /* Recursively transform child, allowing it to push up quals ... */
3699 245800 : child = remove_useless_results_recurse(root, child,
3700 : &f->quals,
3701 : dropped_outer_joins);
3702 : /* ... and stick it back into the tree */
3703 245800 : lfirst(cell) = child;
3704 :
3705 : /*
3706 : * If it's an RTE_RESULT with at least one sibling, and no sibling
3707 : * references dependent PHVs, we can drop it. We don't yet know
3708 : * what the inner join's final relid set will be, so postpone
3709 : * cleanup of PHVs etc till after this loop.
3710 : */
3711 251436 : if (list_length(f->fromlist) > 1 &&
3712 5636 : (varno = get_result_relid(root, child)) != 0 &&
3713 346 : !find_dependent_phvs_in_jointree(root, (Node *) f, varno))
3714 : {
3715 322 : f->fromlist = foreach_delete_current(f->fromlist, cell);
3716 322 : result_relids = bms_add_member(result_relids, varno);
3717 : }
3718 : }
3719 :
3720 : /*
3721 : * Clean up if we dropped any RTE_RESULT RTEs. This is a bit
3722 : * inefficient if there's more than one, but it seems better to
3723 : * optimize the support code for the single-relid case.
3724 : */
3725 242308 : if (result_relids)
3726 : {
3727 310 : int varno = -1;
3728 :
3729 632 : while ((varno = bms_next_member(result_relids, varno)) >= 0)
3730 322 : remove_result_refs(root, varno, (Node *) f);
3731 : }
3732 :
3733 : /*
3734 : * If the FromExpr now has only one child, see if we can elide it.
3735 : * This is always valid if there are no quals, except at the top of
3736 : * the jointree (since Query.jointree is required to point to a
3737 : * FromExpr). Otherwise, we can do it if we can push the quals up to
3738 : * the parent node.
3739 : *
3740 : * Note: while it would not be terribly hard to generalize this
3741 : * transformation to merge multi-child FromExprs into their parent
3742 : * FromExpr, that risks making the parent join too expensive to plan.
3743 : * We leave it to later processing to decide heuristically whether
3744 : * that's a good idea. Pulling up a single child is always OK,
3745 : * however.
3746 : */
3747 242308 : if (list_length(f->fromlist) == 1 &&
3748 240372 : f != root->parse->jointree &&
3749 6676 : (f->quals == NULL || parent_quals != NULL))
3750 : {
3751 : /*
3752 : * Merge any quals up to parent. They should be in implicit-AND
3753 : * format by now, so we just need to concatenate lists. Put the
3754 : * child quals at the front, on the grounds that they should
3755 : * nominally be evaluated earlier.
3756 : */
3757 2740 : if (f->quals != NULL)
3758 1320 : *parent_quals = (Node *)
3759 1320 : list_concat(castNode(List, f->quals),
3760 : castNode(List, *parent_quals));
3761 2740 : return (Node *) linitial(f->fromlist);
3762 : }
3763 : }
3764 64806 : else if (IsA(jtnode, JoinExpr))
3765 : {
3766 64806 : JoinExpr *j = (JoinExpr *) jtnode;
3767 : int varno;
3768 :
3769 : /*
3770 : * First, recurse. We can absorb pushed-up FromExpr quals from either
3771 : * child into this node if the jointype is INNER, since then this is
3772 : * equivalent to a FromExpr. When the jointype is LEFT, we can absorb
3773 : * quals from the RHS child into the current node, as they're
3774 : * essentially degenerate quals of the outer join. Moreover, if we've
3775 : * been passed down a parent_quals pointer then we can allow quals of
3776 : * the LHS child to be absorbed into the parent. (This is important
3777 : * to ensure we remove single-child FromExprs immediately below
3778 : * commutable left joins.) For other jointypes, we can't move child
3779 : * quals up, or at least there's no particular reason to.
3780 : */
3781 64806 : j->larg = remove_useless_results_recurse(root, j->larg,
3782 64806 : (j->jointype == JOIN_INNER) ?
3783 : &j->quals :
3784 50730 : (j->jointype == JOIN_LEFT) ?
3785 50730 : parent_quals : NULL,
3786 : dropped_outer_joins);
3787 64806 : j->rarg = remove_useless_results_recurse(root, j->rarg,
3788 64806 : (j->jointype == JOIN_INNER ||
3789 50730 : j->jointype == JOIN_LEFT) ?
3790 : &j->quals : NULL,
3791 : dropped_outer_joins);
3792 :
3793 : /* Apply join-type-specific optimization rules */
3794 64806 : switch (j->jointype)
3795 : {
3796 14076 : case JOIN_INNER:
3797 :
3798 : /*
3799 : * An inner join is equivalent to a FromExpr, so if either
3800 : * side was simplified to an RTE_RESULT rel, we can replace
3801 : * the join with a FromExpr with just the other side.
3802 : * Furthermore, we can elide that FromExpr according to the
3803 : * same rules as above.
3804 : *
3805 : * Just as in the FromExpr case, we can't simplify if the
3806 : * other input rel references any PHVs that are marked as to
3807 : * be evaluated at the RTE_RESULT rel, because we can't
3808 : * postpone their evaluation in that case. But we only have
3809 : * to check this in cases where it's syntactically legal for
3810 : * the other input to have a LATERAL reference to the
3811 : * RTE_RESULT rel. Only RHSes of inner and left joins are
3812 : * allowed to have such refs.
3813 : */
3814 14076 : if ((varno = get_result_relid(root, j->larg)) != 0 &&
3815 96 : !find_dependent_phvs_in_jointree(root, j->rarg, varno))
3816 : {
3817 96 : remove_result_refs(root, varno, j->rarg);
3818 96 : if (j->quals != NULL && parent_quals == NULL)
3819 12 : jtnode = (Node *)
3820 12 : makeFromExpr(list_make1(j->rarg), j->quals);
3821 : else
3822 : {
3823 : /* Merge any quals up to parent */
3824 84 : if (j->quals != NULL)
3825 60 : *parent_quals = (Node *)
3826 60 : list_concat(castNode(List, j->quals),
3827 : castNode(List, *parent_quals));
3828 84 : jtnode = j->rarg;
3829 : }
3830 : }
3831 13980 : else if ((varno = get_result_relid(root, j->rarg)) != 0)
3832 : {
3833 850 : remove_result_refs(root, varno, j->larg);
3834 850 : if (j->quals != NULL && parent_quals == NULL)
3835 12 : jtnode = (Node *)
3836 12 : makeFromExpr(list_make1(j->larg), j->quals);
3837 : else
3838 : {
3839 : /* Merge any quals up to parent */
3840 838 : if (j->quals != NULL)
3841 600 : *parent_quals = (Node *)
3842 600 : list_concat(castNode(List, j->quals),
3843 : castNode(List, *parent_quals));
3844 838 : jtnode = j->larg;
3845 : }
3846 : }
3847 14076 : break;
3848 44798 : case JOIN_LEFT:
3849 :
3850 : /*
3851 : * We can simplify this case if the RHS is an RTE_RESULT, with
3852 : * two different possibilities:
3853 : *
3854 : * If the qual is empty (JOIN ON TRUE), then the join can be
3855 : * strength-reduced to a plain inner join, since each LHS row
3856 : * necessarily has exactly one join partner. So we can always
3857 : * discard the RHS, much as in the JOIN_INNER case above.
3858 : * (Again, the LHS could not contain a lateral reference to
3859 : * the RHS.)
3860 : *
3861 : * Otherwise, it's still true that each LHS row should be
3862 : * returned exactly once, and since the RHS returns no columns
3863 : * (unless there are PHVs that have to be evaluated there), we
3864 : * don't much care if it's null-extended or not. So in this
3865 : * case also, we can just ignore the qual and discard the left
3866 : * join.
3867 : */
3868 44798 : if ((varno = get_result_relid(root, j->rarg)) != 0 &&
3869 150 : (j->quals == NULL ||
3870 90 : !find_dependent_phvs(root, varno)))
3871 : {
3872 60 : remove_result_refs(root, varno, j->larg);
3873 60 : *dropped_outer_joins = bms_add_member(*dropped_outer_joins,
3874 : j->rtindex);
3875 60 : jtnode = j->larg;
3876 : }
3877 44798 : break;
3878 3202 : case JOIN_SEMI:
3879 :
3880 : /*
3881 : * We may simplify this case if the RHS is an RTE_RESULT; the
3882 : * join qual becomes effectively just a filter qual for the
3883 : * LHS, since we should either return the LHS row or not. The
3884 : * filter clause must go into a new FromExpr if we can't push
3885 : * it up to the parent.
3886 : *
3887 : * There is a fine point about PHVs that are supposed to be
3888 : * evaluated at the RHS. Such PHVs could only appear in the
3889 : * semijoin's qual, since the rest of the query cannot
3890 : * reference any outputs of the semijoin's RHS. Therefore,
3891 : * they can't actually go to null before being examined, and
3892 : * it'd be OK to just remove the PHV wrapping. We don't have
3893 : * infrastructure for that, but remove_result_refs() will
3894 : * relabel them as to be evaluated at the LHS, which is fine.
3895 : *
3896 : * Also, we don't need to worry about removing traces of the
3897 : * join's rtindex, since it hasn't got one.
3898 : */
3899 3202 : if ((varno = get_result_relid(root, j->rarg)) != 0)
3900 : {
3901 : Assert(j->rtindex == 0);
3902 36 : remove_result_refs(root, varno, j->larg);
3903 36 : if (j->quals != NULL && parent_quals == NULL)
3904 0 : jtnode = (Node *)
3905 0 : makeFromExpr(list_make1(j->larg), j->quals);
3906 : else
3907 : {
3908 : /* Merge any quals up to parent */
3909 36 : if (j->quals != NULL)
3910 36 : *parent_quals = (Node *)
3911 36 : list_concat(castNode(List, j->quals),
3912 : castNode(List, *parent_quals));
3913 36 : jtnode = j->larg;
3914 : }
3915 : }
3916 3202 : break;
3917 2730 : case JOIN_FULL:
3918 : case JOIN_ANTI:
3919 : /* We have no special smarts for these cases */
3920 2730 : break;
3921 0 : default:
3922 : /* Note: JOIN_RIGHT should be gone at this point */
3923 0 : elog(ERROR, "unrecognized join type: %d",
3924 : (int) j->jointype);
3925 : break;
3926 : }
3927 : }
3928 : else
3929 0 : elog(ERROR, "unrecognized node type: %d",
3930 : (int) nodeTag(jtnode));
3931 608104 : return jtnode;
3932 : }
3933 :
3934 : /*
3935 : * get_result_relid
3936 : * If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
3937 : * otherwise return 0.
3938 : */
3939 : static int
3940 81692 : get_result_relid(PlannerInfo *root, Node *jtnode)
3941 : {
3942 : int varno;
3943 :
3944 81692 : if (!IsA(jtnode, RangeTblRef))
3945 6874 : return 0;
3946 74818 : varno = ((RangeTblRef *) jtnode)->rtindex;
3947 74818 : if (rt_fetch(varno, root->parse->rtable)->rtekind != RTE_RESULT)
3948 73340 : return 0;
3949 1478 : return varno;
3950 : }
3951 :
3952 : /*
3953 : * remove_result_refs
3954 : * Helper routine for dropping an unneeded RTE_RESULT RTE.
3955 : *
3956 : * This doesn't physically remove the RTE from the jointree, because that's
3957 : * more easily handled in remove_useless_results_recurse. What it does do
3958 : * is the necessary cleanup in the rest of the tree: we must adjust any PHVs
3959 : * that may reference the RTE. Be sure to call this at a point where the
3960 : * jointree is valid (no disconnected nodes).
3961 : *
3962 : * Note that we don't need to process the append_rel_list, since RTEs
3963 : * referenced directly in the jointree won't be appendrel members.
3964 : *
3965 : * varno is the RTE_RESULT's relid.
3966 : * newjtloc is the jointree location at which any PHVs referencing the
3967 : * RTE_RESULT should be evaluated instead.
3968 : */
3969 : static void
3970 1364 : remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc)
3971 : {
3972 : /* Fix up PlaceHolderVars as needed */
3973 : /* If there are no PHVs anywhere, we can skip this bit */
3974 1364 : if (root->glob->lastPHId != 0)
3975 : {
3976 : Relids subrelids;
3977 :
3978 244 : subrelids = get_relids_in_jointree(newjtloc, true, false);
3979 : Assert(!bms_is_empty(subrelids));
3980 244 : substitute_phv_relids((Node *) root->parse, varno, subrelids);
3981 244 : fix_append_rel_relids(root, varno, subrelids);
3982 : }
3983 :
3984 : /*
3985 : * We also need to remove any PlanRowMark referencing the RTE, but we
3986 : * postpone that work until we return to remove_useless_result_rtes.
3987 : */
3988 1364 : }
3989 :
3990 :
3991 : /*
3992 : * find_dependent_phvs - are there any PlaceHolderVars whose relids are
3993 : * exactly the given varno?
3994 : *
3995 : * find_dependent_phvs should be used when we want to see if there are
3996 : * any such PHVs anywhere in the Query. Another use-case is to see if
3997 : * a subtree of the join tree contains such PHVs; but for that, we have
3998 : * to look not only at the join tree nodes themselves but at the
3999 : * referenced RTEs. For that, use find_dependent_phvs_in_jointree.
4000 : */
4001 :
4002 : typedef struct
4003 : {
4004 : Relids relids;
4005 : int sublevels_up;
4006 : } find_dependent_phvs_context;
4007 :
4008 : static bool
4009 2400 : find_dependent_phvs_walker(Node *node,
4010 : find_dependent_phvs_context *context)
4011 : {
4012 2400 : if (node == NULL)
4013 564 : return false;
4014 1836 : if (IsA(node, PlaceHolderVar))
4015 : {
4016 156 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4017 :
4018 312 : if (phv->phlevelsup == context->sublevels_up &&
4019 156 : bms_equal(context->relids, phv->phrels))
4020 114 : return true;
4021 : /* fall through to examine children */
4022 : }
4023 1722 : if (IsA(node, Query))
4024 : {
4025 : /* Recurse into subselects */
4026 : bool result;
4027 :
4028 48 : context->sublevels_up++;
4029 48 : result = query_tree_walker((Query *) node,
4030 : find_dependent_phvs_walker,
4031 : context, 0);
4032 48 : context->sublevels_up--;
4033 48 : return result;
4034 : }
4035 : /* Shouldn't need to handle most planner auxiliary nodes here */
4036 : Assert(!IsA(node, SpecialJoinInfo));
4037 : Assert(!IsA(node, PlaceHolderInfo));
4038 : Assert(!IsA(node, MinMaxAggInfo));
4039 :
4040 1674 : return expression_tree_walker(node, find_dependent_phvs_walker, context);
4041 : }
4042 :
4043 : static bool
4044 90 : find_dependent_phvs(PlannerInfo *root, int varno)
4045 : {
4046 : find_dependent_phvs_context context;
4047 :
4048 : /* If there are no PHVs anywhere, we needn't work hard */
4049 90 : if (root->glob->lastPHId == 0)
4050 0 : return false;
4051 :
4052 90 : context.relids = bms_make_singleton(varno);
4053 90 : context.sublevels_up = 0;
4054 :
4055 90 : if (query_tree_walker(root->parse, find_dependent_phvs_walker, &context, 0))
4056 90 : return true;
4057 : /* The append_rel_list could be populated already, so check it too */
4058 0 : if (expression_tree_walker((Node *) root->append_rel_list,
4059 : find_dependent_phvs_walker,
4060 : &context))
4061 0 : return true;
4062 0 : return false;
4063 : }
4064 :
4065 : static bool
4066 442 : find_dependent_phvs_in_jointree(PlannerInfo *root, Node *node, int varno)
4067 : {
4068 : find_dependent_phvs_context context;
4069 : Relids subrelids;
4070 : int relid;
4071 :
4072 : /* If there are no PHVs anywhere, we needn't work hard */
4073 442 : if (root->glob->lastPHId == 0)
4074 376 : return false;
4075 :
4076 66 : context.relids = bms_make_singleton(varno);
4077 66 : context.sublevels_up = 0;
4078 :
4079 : /*
4080 : * See if the jointree fragment itself contains references (in join quals)
4081 : */
4082 66 : if (find_dependent_phvs_walker(node, &context))
4083 0 : return true;
4084 :
4085 : /*
4086 : * Otherwise, identify the set of referenced RTEs (we can ignore joins,
4087 : * since they should be flattened already, so their join alias lists no
4088 : * longer matter), and tediously check each RTE. We can ignore RTEs that
4089 : * are not marked LATERAL, though, since they couldn't possibly contain
4090 : * any cross-references to other RTEs.
4091 : */
4092 66 : subrelids = get_relids_in_jointree(node, false, false);
4093 66 : relid = -1;
4094 144 : while ((relid = bms_next_member(subrelids, relid)) >= 0)
4095 : {
4096 102 : RangeTblEntry *rte = rt_fetch(relid, root->parse->rtable);
4097 :
4098 126 : if (rte->lateral &&
4099 24 : range_table_entry_walker(rte, find_dependent_phvs_walker, &context, 0))
4100 24 : return true;
4101 : }
4102 :
4103 42 : return false;
4104 : }
4105 :
4106 : /*
4107 : * substitute_phv_relids - adjust PlaceHolderVar relid sets after pulling up
4108 : * a subquery or removing an RTE_RESULT jointree item
4109 : *
4110 : * Find any PlaceHolderVar nodes in the given tree that reference the
4111 : * pulled-up relid, and change them to reference the replacement relid(s).
4112 : *
4113 : * NOTE: although this has the form of a walker, we cheat and modify the
4114 : * nodes in-place. This should be OK since the tree was copied by
4115 : * pullup_replace_vars earlier. Avoid scribbling on the original values of
4116 : * the bitmapsets, though, because expression_tree_mutator doesn't copy those.
4117 : */
4118 :
4119 : typedef struct
4120 : {
4121 : int varno;
4122 : int sublevels_up;
4123 : Relids subrelids;
4124 : } substitute_phv_relids_context;
4125 :
4126 : static bool
4127 248618 : substitute_phv_relids_walker(Node *node,
4128 : substitute_phv_relids_context *context)
4129 : {
4130 248618 : if (node == NULL)
4131 92170 : return false;
4132 156448 : if (IsA(node, PlaceHolderVar))
4133 : {
4134 7284 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4135 :
4136 14536 : if (phv->phlevelsup == context->sublevels_up &&
4137 7252 : bms_is_member(context->varno, phv->phrels))
4138 : {
4139 10504 : phv->phrels = bms_union(phv->phrels,
4140 5252 : context->subrelids);
4141 5252 : phv->phrels = bms_del_member(phv->phrels,
4142 : context->varno);
4143 : /* Assert we haven't broken the PHV */
4144 : Assert(!bms_is_empty(phv->phrels));
4145 : }
4146 : /* fall through to examine children */
4147 : }
4148 156448 : if (IsA(node, Query))
4149 : {
4150 : /* Recurse into subselects */
4151 : bool result;
4152 :
4153 3802 : context->sublevels_up++;
4154 3802 : result = query_tree_walker((Query *) node,
4155 : substitute_phv_relids_walker,
4156 : context, 0);
4157 3802 : context->sublevels_up--;
4158 3802 : return result;
4159 : }
4160 : /* Shouldn't need to handle planner auxiliary nodes here */
4161 : Assert(!IsA(node, SpecialJoinInfo));
4162 : Assert(!IsA(node, AppendRelInfo));
4163 : Assert(!IsA(node, PlaceHolderInfo));
4164 : Assert(!IsA(node, MinMaxAggInfo));
4165 :
4166 152646 : return expression_tree_walker(node, substitute_phv_relids_walker, context);
4167 : }
4168 :
4169 : static void
4170 2250 : substitute_phv_relids(Node *node, int varno, Relids subrelids)
4171 : {
4172 : substitute_phv_relids_context context;
4173 :
4174 2250 : context.varno = varno;
4175 2250 : context.sublevels_up = 0;
4176 2250 : context.subrelids = subrelids;
4177 :
4178 : /*
4179 : * Must be prepared to start with a Query or a bare expression tree.
4180 : */
4181 2250 : query_or_expression_tree_walker(node,
4182 : substitute_phv_relids_walker,
4183 : &context,
4184 : 0);
4185 2250 : }
4186 :
4187 : /*
4188 : * fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
4189 : *
4190 : * When we pull up a subquery, any AppendRelInfo references to the subquery's
4191 : * RT index have to be replaced by the substituted relid (and there had better
4192 : * be only one). We also need to apply substitute_phv_relids to their
4193 : * translated_vars lists, since those might contain PlaceHolderVars.
4194 : *
4195 : * We assume we may modify the AppendRelInfo nodes in-place.
4196 : */
4197 : static void
4198 8102 : fix_append_rel_relids(PlannerInfo *root, int varno, Relids subrelids)
4199 : {
4200 : ListCell *l;
4201 8102 : int subvarno = -1;
4202 :
4203 : /*
4204 : * We only want to extract the member relid once, but we mustn't fail
4205 : * immediately if there are multiple members; it could be that none of the
4206 : * AppendRelInfo nodes refer to it. So compute it on first use. Note that
4207 : * bms_singleton_member will complain if set is not singleton.
4208 : */
4209 19272 : foreach(l, root->append_rel_list)
4210 : {
4211 11170 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
4212 :
4213 : /* The parent_relid shouldn't ever be a pullup target */
4214 : Assert(appinfo->parent_relid != varno);
4215 :
4216 11170 : if (appinfo->child_relid == varno)
4217 : {
4218 6020 : if (subvarno < 0)
4219 6020 : subvarno = bms_singleton_member(subrelids);
4220 6020 : appinfo->child_relid = subvarno;
4221 : }
4222 :
4223 : /* Also fix up any PHVs in its translated vars */
4224 11170 : if (root->glob->lastPHId != 0)
4225 114 : substitute_phv_relids((Node *) appinfo->translated_vars,
4226 : varno, subrelids);
4227 : }
4228 8102 : }
4229 :
4230 : /*
4231 : * get_relids_in_jointree: get set of RT indexes present in a jointree
4232 : *
4233 : * Base-relation relids are always included in the result.
4234 : * If include_outer_joins is true, outer-join RT indexes are included.
4235 : * If include_inner_joins is true, inner-join RT indexes are included.
4236 : *
4237 : * Note that for most purposes in the planner, outer joins are included
4238 : * in standard relid sets. Setting include_inner_joins true is only
4239 : * appropriate for special purposes during subquery flattening.
4240 : */
4241 : Relids
4242 91222 : get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
4243 : bool include_inner_joins)
4244 : {
4245 91222 : Relids result = NULL;
4246 :
4247 91222 : if (jtnode == NULL)
4248 0 : return result;
4249 91222 : if (IsA(jtnode, RangeTblRef))
4250 : {
4251 45960 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4252 :
4253 45960 : result = bms_make_singleton(varno);
4254 : }
4255 45262 : else if (IsA(jtnode, FromExpr))
4256 : {
4257 39068 : FromExpr *f = (FromExpr *) jtnode;
4258 : ListCell *l;
4259 :
4260 79332 : foreach(l, f->fromlist)
4261 : {
4262 40264 : result = bms_join(result,
4263 40264 : get_relids_in_jointree(lfirst(l),
4264 : include_outer_joins,
4265 : include_inner_joins));
4266 : }
4267 : }
4268 6194 : else if (IsA(jtnode, JoinExpr))
4269 : {
4270 6194 : JoinExpr *j = (JoinExpr *) jtnode;
4271 :
4272 6194 : result = get_relids_in_jointree(j->larg,
4273 : include_outer_joins,
4274 : include_inner_joins);
4275 6194 : result = bms_join(result,
4276 : get_relids_in_jointree(j->rarg,
4277 : include_outer_joins,
4278 : include_inner_joins));
4279 6194 : if (j->rtindex)
4280 : {
4281 5886 : if (j->jointype == JOIN_INNER)
4282 : {
4283 2636 : if (include_inner_joins)
4284 1010 : result = bms_add_member(result, j->rtindex);
4285 : }
4286 : else
4287 : {
4288 3250 : if (include_outer_joins)
4289 2134 : result = bms_add_member(result, j->rtindex);
4290 : }
4291 : }
4292 : }
4293 : else
4294 0 : elog(ERROR, "unrecognized node type: %d",
4295 : (int) nodeTag(jtnode));
4296 91222 : return result;
4297 : }
4298 :
4299 : /*
4300 : * get_relids_for_join: get set of base+OJ RT indexes making up a join
4301 : */
4302 : Relids
4303 358 : get_relids_for_join(Query *query, int joinrelid)
4304 : {
4305 : Node *jtnode;
4306 :
4307 358 : jtnode = find_jointree_node_for_rel((Node *) query->jointree,
4308 : joinrelid);
4309 358 : if (!jtnode)
4310 0 : elog(ERROR, "could not find join node %d", joinrelid);
4311 358 : return get_relids_in_jointree(jtnode, true, false);
4312 : }
4313 :
4314 : /*
4315 : * find_jointree_node_for_rel: locate jointree node for a base or join RT index
4316 : *
4317 : * Returns NULL if not found
4318 : */
4319 : static Node *
4320 1730 : find_jointree_node_for_rel(Node *jtnode, int relid)
4321 : {
4322 1730 : if (jtnode == NULL)
4323 0 : return NULL;
4324 1730 : if (IsA(jtnode, RangeTblRef))
4325 : {
4326 454 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4327 :
4328 454 : if (relid == varno)
4329 0 : return jtnode;
4330 : }
4331 1276 : else if (IsA(jtnode, FromExpr))
4332 : {
4333 368 : FromExpr *f = (FromExpr *) jtnode;
4334 : ListCell *l;
4335 :
4336 386 : foreach(l, f->fromlist)
4337 : {
4338 386 : jtnode = find_jointree_node_for_rel(lfirst(l), relid);
4339 386 : if (jtnode)
4340 368 : return jtnode;
4341 : }
4342 : }
4343 908 : else if (IsA(jtnode, JoinExpr))
4344 : {
4345 908 : JoinExpr *j = (JoinExpr *) jtnode;
4346 :
4347 908 : if (relid == j->rtindex)
4348 358 : return jtnode;
4349 550 : jtnode = find_jointree_node_for_rel(j->larg, relid);
4350 550 : if (jtnode)
4351 114 : return jtnode;
4352 436 : jtnode = find_jointree_node_for_rel(j->rarg, relid);
4353 436 : if (jtnode)
4354 436 : return jtnode;
4355 : }
4356 : else
4357 0 : elog(ERROR, "unrecognized node type: %d",
4358 : (int) nodeTag(jtnode));
4359 454 : return NULL;
4360 : }
4361 :
4362 : /*
4363 : * get_nullingrels: collect info about which outer joins null which relations
4364 : *
4365 : * The result struct contains, for each leaf relation used in the query,
4366 : * the set of relids of outer joins that potentially null that rel.
4367 : */
4368 : static nullingrel_info *
4369 1138 : get_nullingrels(Query *parse)
4370 : {
4371 1138 : nullingrel_info *result = palloc_object(nullingrel_info);
4372 :
4373 1138 : result->rtlength = list_length(parse->rtable);
4374 1138 : result->nullingrels = palloc0_array(Relids, result->rtlength + 1);
4375 1138 : get_nullingrels_recurse((Node *) parse->jointree, NULL, result);
4376 1138 : return result;
4377 : }
4378 :
4379 : /*
4380 : * Recursive guts of get_nullingrels().
4381 : *
4382 : * Note: at any recursion level, the passed-down upper_nullingrels must be
4383 : * treated as a constant, but it can be stored directly into *info
4384 : * if we're at leaf level. Upper recursion levels do not free their mutated
4385 : * copies of the nullingrels, because those are probably referenced by
4386 : * at least one leaf rel.
4387 : */
4388 : static void
4389 6004 : get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
4390 : nullingrel_info *info)
4391 : {
4392 6004 : if (jtnode == NULL)
4393 0 : return;
4394 6004 : if (IsA(jtnode, RangeTblRef))
4395 : {
4396 3180 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4397 :
4398 : Assert(varno > 0 && varno <= info->rtlength);
4399 3180 : info->nullingrels[varno] = upper_nullingrels;
4400 : }
4401 2824 : else if (IsA(jtnode, FromExpr))
4402 : {
4403 1216 : FromExpr *f = (FromExpr *) jtnode;
4404 : ListCell *l;
4405 :
4406 2866 : foreach(l, f->fromlist)
4407 : {
4408 1650 : get_nullingrels_recurse(lfirst(l), upper_nullingrels, info);
4409 : }
4410 : }
4411 1608 : else if (IsA(jtnode, JoinExpr))
4412 : {
4413 1608 : JoinExpr *j = (JoinExpr *) jtnode;
4414 : Relids local_nullingrels;
4415 :
4416 1608 : switch (j->jointype)
4417 : {
4418 574 : case JOIN_INNER:
4419 574 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4420 574 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4421 574 : break;
4422 1028 : case JOIN_LEFT:
4423 : case JOIN_SEMI:
4424 : case JOIN_ANTI:
4425 1028 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4426 : j->rtindex);
4427 1028 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4428 1028 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4429 1028 : break;
4430 6 : case JOIN_FULL:
4431 6 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4432 : j->rtindex);
4433 6 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4434 6 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4435 6 : break;
4436 0 : case JOIN_RIGHT:
4437 0 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4438 : j->rtindex);
4439 0 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4440 0 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4441 0 : break;
4442 0 : default:
4443 0 : elog(ERROR, "unrecognized join type: %d",
4444 : (int) j->jointype);
4445 : break;
4446 : }
4447 : }
4448 : else
4449 0 : elog(ERROR, "unrecognized node type: %d",
4450 : (int) nodeTag(jtnode));
4451 : }
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