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 : * preprocess_relation_rtes
8 : * replace_empty_jointree
9 : * pull_up_sublinks
10 : * preprocess_function_rtes
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/plancat.h"
40 : #include "optimizer/prep.h"
41 : #include "optimizer/subselect.h"
42 : #include "optimizer/tlist.h"
43 : #include "parser/parse_relation.h"
44 : #include "parser/parsetree.h"
45 : #include "rewrite/rewriteHandler.h"
46 : #include "rewrite/rewriteManip.h"
47 : #include "utils/rel.h"
48 :
49 :
50 : typedef struct nullingrel_info
51 : {
52 : /*
53 : * For each leaf RTE, nullingrels[rti] is the set of relids of outer joins
54 : * that potentially null that RTE.
55 : */
56 : Relids *nullingrels;
57 : /* Length of range table (maximum index in nullingrels[]) */
58 : int rtlength; /* used only for assertion checks */
59 : } nullingrel_info;
60 :
61 : /* Options for wrapping an expression for identification purposes */
62 : typedef enum ReplaceWrapOption
63 : {
64 : REPLACE_WRAP_NONE, /* no expressions need to be wrapped */
65 : REPLACE_WRAP_ALL, /* all expressions need to be wrapped */
66 : REPLACE_WRAP_VARFREE, /* variable-free expressions need to be
67 : * wrapped */
68 : } ReplaceWrapOption;
69 :
70 : typedef struct pullup_replace_vars_context
71 : {
72 : PlannerInfo *root;
73 : List *targetlist; /* tlist of subquery being pulled up */
74 : RangeTblEntry *target_rte; /* RTE of subquery */
75 : int result_relation; /* the index of the result relation in the
76 : * rewritten query */
77 : Relids relids; /* relids within subquery, as numbered after
78 : * pullup (set only if target_rte->lateral) */
79 : nullingrel_info *nullinfo; /* per-RTE nullingrel info (set only if
80 : * target_rte->lateral) */
81 : bool *outer_hasSubLinks; /* -> outer query's hasSubLinks */
82 : int varno; /* varno of subquery */
83 : ReplaceWrapOption wrap_option; /* do we need certain outputs to be PHVs? */
84 : Node **rv_cache; /* cache for results with PHVs */
85 : } pullup_replace_vars_context;
86 :
87 : typedef struct reduce_outer_joins_pass1_state
88 : {
89 : Relids relids; /* base relids within this subtree */
90 : bool contains_outer; /* does subtree contain outer join(s)? */
91 : List *sub_states; /* List of states for subtree components */
92 : } reduce_outer_joins_pass1_state;
93 :
94 : typedef struct reduce_outer_joins_pass2_state
95 : {
96 : Relids inner_reduced; /* OJ relids reduced to plain inner joins */
97 : List *partial_reduced; /* List of partially reduced FULL joins */
98 : } reduce_outer_joins_pass2_state;
99 :
100 : typedef struct reduce_outer_joins_partial_state
101 : {
102 : int full_join_rti; /* RT index of a formerly-FULL join */
103 : Relids unreduced_side; /* relids in its still-nullable side */
104 : } reduce_outer_joins_partial_state;
105 :
106 : static Query *expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
107 : RangeTblEntry *rte, int rt_index,
108 : Relation relation);
109 : static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
110 : Relids *relids);
111 : static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
112 : Node **jtlink1, Relids available_rels1,
113 : Node **jtlink2, Relids available_rels2);
114 : static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
115 : JoinExpr *lowest_outer_join,
116 : AppendRelInfo *containing_appendrel);
117 : static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
118 : RangeTblEntry *rte,
119 : JoinExpr *lowest_outer_join,
120 : AppendRelInfo *containing_appendrel);
121 : static Node *pull_up_simple_union_all(PlannerInfo *root, Node *jtnode,
122 : RangeTblEntry *rte);
123 : static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
124 : int parentRTindex, Query *setOpQuery,
125 : int childRToffset);
126 : static void make_setop_translation_list(Query *query, int newvarno,
127 : AppendRelInfo *appinfo);
128 : static bool is_simple_subquery(PlannerInfo *root, Query *subquery,
129 : RangeTblEntry *rte,
130 : JoinExpr *lowest_outer_join);
131 : static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
132 : RangeTblEntry *rte);
133 : static bool is_simple_values(PlannerInfo *root, RangeTblEntry *rte);
134 : static Node *pull_up_constant_function(PlannerInfo *root, Node *jtnode,
135 : RangeTblEntry *rte,
136 : AppendRelInfo *containing_appendrel);
137 : static bool is_simple_union_all(Query *subquery);
138 : static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery,
139 : List *colTypes);
140 : static bool is_safe_append_member(Query *subquery);
141 : static bool jointree_contains_lateral_outer_refs(PlannerInfo *root,
142 : Node *jtnode, bool restricted,
143 : Relids safe_upper_varnos);
144 : static void perform_pullup_replace_vars(PlannerInfo *root,
145 : pullup_replace_vars_context *rvcontext,
146 : AppendRelInfo *containing_appendrel);
147 : static void replace_vars_in_jointree(Node *jtnode,
148 : pullup_replace_vars_context *context);
149 : static Node *pullup_replace_vars(Node *expr,
150 : pullup_replace_vars_context *context);
151 : static Node *pullup_replace_vars_callback(Var *var,
152 : replace_rte_variables_context *context);
153 : static Query *pullup_replace_vars_subquery(Query *query,
154 : pullup_replace_vars_context *context);
155 : static reduce_outer_joins_pass1_state *reduce_outer_joins_pass1(Node *jtnode);
156 : static void reduce_outer_joins_pass2(Node *jtnode,
157 : reduce_outer_joins_pass1_state *state1,
158 : reduce_outer_joins_pass2_state *state2,
159 : PlannerInfo *root,
160 : Relids nonnullable_rels,
161 : List *forced_null_vars);
162 : static void report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
163 : int rtindex, Relids relids);
164 : static Node *remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
165 : Node **parent_quals,
166 : Relids *dropped_outer_joins);
167 : static int get_result_relid(PlannerInfo *root, Node *jtnode);
168 : static void remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc);
169 : static bool find_dependent_phvs(PlannerInfo *root, int varno);
170 : static bool find_dependent_phvs_in_jointree(PlannerInfo *root,
171 : Node *node, int varno);
172 : static void substitute_phv_relids(Node *node,
173 : int varno, Relids subrelids);
174 : static void fix_append_rel_relids(PlannerInfo *root, int varno,
175 : Relids subrelids);
176 : static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
177 : static nullingrel_info *get_nullingrels(Query *parse);
178 : static void get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
179 : nullingrel_info *info);
180 :
181 :
182 : /*
183 : * transform_MERGE_to_join
184 : * Replace a MERGE's jointree to also include the target relation.
185 : */
186 : void
187 530800 : transform_MERGE_to_join(Query *parse)
188 : {
189 : RangeTblEntry *joinrte;
190 : JoinExpr *joinexpr;
191 : bool have_action[NUM_MERGE_MATCH_KINDS];
192 : JoinType jointype;
193 : int joinrti;
194 : List *vars;
195 : RangeTblRef *rtr;
196 : FromExpr *target;
197 : Node *source;
198 : int sourcerti;
199 :
200 530800 : if (parse->commandType != CMD_MERGE)
201 528892 : return;
202 :
203 : /* XXX probably bogus */
204 1908 : vars = NIL;
205 :
206 : /*
207 : * Work out what kind of join is required. If there any WHEN NOT MATCHED
208 : * BY SOURCE/TARGET actions, an outer join is required so that we process
209 : * all unmatched tuples from the source and/or target relations.
210 : * Otherwise, we can use an inner join.
211 : */
212 1908 : have_action[MERGE_WHEN_MATCHED] = false;
213 1908 : have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = false;
214 1908 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = false;
215 :
216 6732 : foreach_node(MergeAction, action, parse->mergeActionList)
217 : {
218 2916 : if (action->commandType != CMD_NOTHING)
219 2838 : have_action[action->matchKind] = true;
220 : }
221 :
222 1908 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] &&
223 126 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
224 96 : jointype = JOIN_FULL;
225 1812 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
226 30 : jointype = JOIN_LEFT;
227 1782 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
228 830 : jointype = JOIN_RIGHT;
229 : else
230 952 : jointype = JOIN_INNER;
231 :
232 : /* Manufacture a join RTE to use. */
233 1908 : joinrte = makeNode(RangeTblEntry);
234 1908 : joinrte->rtekind = RTE_JOIN;
235 1908 : joinrte->jointype = jointype;
236 1908 : joinrte->joinmergedcols = 0;
237 1908 : joinrte->joinaliasvars = vars;
238 1908 : joinrte->joinleftcols = NIL; /* MERGE does not allow JOIN USING */
239 1908 : joinrte->joinrightcols = NIL; /* ditto */
240 1908 : joinrte->join_using_alias = NULL;
241 :
242 1908 : joinrte->alias = NULL;
243 1908 : joinrte->eref = makeAlias("*MERGE*", NIL);
244 1908 : joinrte->lateral = false;
245 1908 : joinrte->inh = false;
246 1908 : joinrte->inFromCl = true;
247 :
248 : /*
249 : * Add completed RTE to pstate's range table list, so that we know its
250 : * index.
251 : */
252 1908 : parse->rtable = lappend(parse->rtable, joinrte);
253 1908 : joinrti = list_length(parse->rtable);
254 :
255 : /*
256 : * Create a JOIN between the target and the source relation.
257 : *
258 : * Here the target is identified by parse->mergeTargetRelation. For a
259 : * regular table, this will equal parse->resultRelation, but for a
260 : * trigger-updatable view, it will be the expanded view subquery that we
261 : * need to pull data from.
262 : *
263 : * The source relation is in parse->jointree->fromlist, but any quals in
264 : * parse->jointree->quals are restrictions on the target relation (if the
265 : * target relation is an auto-updatable view).
266 : */
267 : /* target rel, with any quals */
268 1908 : rtr = makeNode(RangeTblRef);
269 1908 : rtr->rtindex = parse->mergeTargetRelation;
270 1908 : target = makeFromExpr(list_make1(rtr), parse->jointree->quals);
271 :
272 : /* source rel (expect exactly one -- see transformMergeStmt()) */
273 : Assert(list_length(parse->jointree->fromlist) == 1);
274 1908 : source = linitial(parse->jointree->fromlist);
275 :
276 : /*
277 : * index of source rel (expect either a RangeTblRef or a JoinExpr -- see
278 : * transformFromClauseItem()).
279 : */
280 1908 : if (IsA(source, RangeTblRef))
281 1824 : sourcerti = ((RangeTblRef *) source)->rtindex;
282 84 : else if (IsA(source, JoinExpr))
283 84 : sourcerti = ((JoinExpr *) source)->rtindex;
284 : else
285 : {
286 0 : elog(ERROR, "unrecognized source node type: %d",
287 : (int) nodeTag(source));
288 : sourcerti = 0; /* keep compiler quiet */
289 : }
290 :
291 : /* Join the source and target */
292 1908 : joinexpr = makeNode(JoinExpr);
293 1908 : joinexpr->jointype = jointype;
294 1908 : joinexpr->isNatural = false;
295 1908 : joinexpr->larg = (Node *) target;
296 1908 : joinexpr->rarg = source;
297 1908 : joinexpr->usingClause = NIL;
298 1908 : joinexpr->join_using_alias = NULL;
299 1908 : joinexpr->quals = parse->mergeJoinCondition;
300 1908 : joinexpr->alias = NULL;
301 1908 : joinexpr->rtindex = joinrti;
302 :
303 : /* Make the new join be the sole entry in the query's jointree */
304 1908 : parse->jointree->fromlist = list_make1(joinexpr);
305 1908 : parse->jointree->quals = NULL;
306 :
307 : /*
308 : * If necessary, mark parse->targetlist entries that refer to the target
309 : * as nullable by the join. Normally the targetlist will be empty for a
310 : * MERGE, but if the target is a trigger-updatable view, it will contain a
311 : * whole-row Var referring to the expanded view query.
312 : */
313 1908 : if (parse->targetList != NIL &&
314 42 : (jointype == JOIN_RIGHT || jointype == JOIN_FULL))
315 42 : parse->targetList = (List *)
316 42 : add_nulling_relids((Node *) parse->targetList,
317 42 : bms_make_singleton(parse->mergeTargetRelation),
318 42 : bms_make_singleton(joinrti));
319 :
320 : /*
321 : * If the source relation is on the outer side of the join, mark any
322 : * source relation Vars in the join condition, actions, and RETURNING list
323 : * as nullable by the join. These Vars will be added to the targetlist by
324 : * preprocess_targetlist(), so it's important to mark them correctly here.
325 : *
326 : * It might seem that this is not necessary for Vars in the join
327 : * condition, since it is inside the join, but it is also needed above the
328 : * join (in the ModifyTable node) to distinguish between the MATCHED and
329 : * NOT MATCHED BY SOURCE cases -- see ExecMergeMatched(). Note that this
330 : * creates a modified copy of the join condition, for use above the join,
331 : * without modifying the original join condition, inside the join.
332 : */
333 1908 : if (jointype == JOIN_LEFT || jointype == JOIN_FULL)
334 : {
335 126 : parse->mergeJoinCondition =
336 126 : add_nulling_relids(parse->mergeJoinCondition,
337 126 : bms_make_singleton(sourcerti),
338 126 : bms_make_singleton(joinrti));
339 :
340 600 : foreach_node(MergeAction, action, parse->mergeActionList)
341 : {
342 348 : action->qual =
343 348 : add_nulling_relids(action->qual,
344 348 : bms_make_singleton(sourcerti),
345 348 : bms_make_singleton(joinrti));
346 :
347 348 : action->targetList = (List *)
348 348 : add_nulling_relids((Node *) action->targetList,
349 348 : bms_make_singleton(sourcerti),
350 348 : bms_make_singleton(joinrti));
351 : }
352 :
353 126 : parse->returningList = (List *)
354 126 : add_nulling_relids((Node *) parse->returningList,
355 126 : bms_make_singleton(sourcerti),
356 126 : bms_make_singleton(joinrti));
357 : }
358 :
359 : /*
360 : * If there are any WHEN NOT MATCHED BY SOURCE actions, the executor will
361 : * use the join condition to distinguish between MATCHED and NOT MATCHED
362 : * BY SOURCE cases. Otherwise, it's no longer needed, and we set it to
363 : * NULL, saving cycles during planning and execution.
364 : *
365 : * We need to be careful though: the executor evaluates this condition
366 : * using the output of the join subplan node, which nulls the output from
367 : * the source relation when the join condition doesn't match. That risks
368 : * producing incorrect results when rechecking using a "non-strict" join
369 : * condition, such as "src.col IS NOT DISTINCT FROM tgt.col". To guard
370 : * against that, we add an additional "src IS NOT NULL" check to the join
371 : * condition, so that it does the right thing when performing a recheck
372 : * based on the output of the join subplan.
373 : */
374 1908 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
375 : {
376 : Var *var;
377 : NullTest *ntest;
378 :
379 : /* source wholerow Var (nullable by the new join) */
380 126 : var = makeWholeRowVar(rt_fetch(sourcerti, parse->rtable),
381 : sourcerti, 0, false);
382 126 : var->varnullingrels = bms_make_singleton(joinrti);
383 :
384 : /* "src IS NOT NULL" check */
385 126 : ntest = makeNode(NullTest);
386 126 : ntest->arg = (Expr *) var;
387 126 : ntest->nulltesttype = IS_NOT_NULL;
388 126 : ntest->argisrow = false;
389 126 : ntest->location = -1;
390 :
391 : /* combine it with the original join condition */
392 126 : parse->mergeJoinCondition =
393 126 : (Node *) make_and_qual((Node *) ntest, parse->mergeJoinCondition);
394 : }
395 : else
396 1782 : parse->mergeJoinCondition = NULL; /* join condition not needed */
397 : }
398 :
399 : /*
400 : * preprocess_relation_rtes
401 : * Do the preprocessing work for any relation RTEs in the FROM clause.
402 : *
403 : * This scans the rangetable for relation RTEs and retrieves the necessary
404 : * catalog information for each relation. Using this information, it clears
405 : * the inh flag for any relation that has no children, collects not-null
406 : * attribute numbers for any relation that has column not-null constraints, and
407 : * expands virtual generated columns for any relation that contains them.
408 : *
409 : * Note that expanding virtual generated columns may cause the query tree to
410 : * have new copies of rangetable entries. Therefore, we have to use list_nth
411 : * instead of foreach when iterating over the query's rangetable.
412 : *
413 : * Returns a modified copy of the query tree, if any relations with virtual
414 : * generated columns are present.
415 : */
416 : Query *
417 571654 : preprocess_relation_rtes(PlannerInfo *root)
418 : {
419 571654 : Query *parse = root->parse;
420 : int rtable_size;
421 : int rt_index;
422 :
423 571654 : rtable_size = list_length(parse->rtable);
424 :
425 1276208 : for (rt_index = 0; rt_index < rtable_size; rt_index++)
426 : {
427 704554 : RangeTblEntry *rte = rt_fetch(rt_index + 1, parse->rtable);
428 : Relation relation;
429 :
430 : /* We only care about relation RTEs. */
431 704554 : if (rte->rtekind != RTE_RELATION)
432 225374 : continue;
433 :
434 : /*
435 : * We need not lock the relation since it was already locked by the
436 : * rewriter.
437 : */
438 479180 : relation = table_open(rte->relid, NoLock);
439 :
440 : /*
441 : * Check to see if the relation actually has any children; if not,
442 : * clear the inh flag so we can treat it as a plain base relation.
443 : *
444 : * Note: this could give a false-positive result, if the rel once had
445 : * children but no longer does. We used to be able to clear rte->inh
446 : * later on when we discovered that, but no more; we have to handle
447 : * such cases as full-fledged inheritance.
448 : */
449 479180 : if (rte->inh)
450 392122 : rte->inh = relation->rd_rel->relhassubclass;
451 :
452 : /*
453 : * Check to see if the relation has any column not-null constraints;
454 : * if so, retrieve the constraint information and store it in a
455 : * relation OID based hash table.
456 : */
457 479180 : get_relation_notnullatts(root, relation);
458 :
459 : /*
460 : * Check to see if the relation has any virtual generated columns; if
461 : * so, replace all Var nodes in the query that reference these columns
462 : * with the generation expressions.
463 : */
464 479180 : parse = expand_virtual_generated_columns(root, parse,
465 : rte, rt_index + 1,
466 : relation);
467 :
468 479180 : table_close(relation, NoLock);
469 : }
470 :
471 571654 : return parse;
472 : }
473 :
474 : /*
475 : * expand_virtual_generated_columns
476 : * Expand virtual generated columns for the given relation.
477 : *
478 : * This checks whether the given relation has any virtual generated columns,
479 : * and if so, replaces all Var nodes in the query that reference those columns
480 : * with their generation expressions.
481 : *
482 : * Returns a modified copy of the query tree if the relation contains virtual
483 : * generated columns.
484 : */
485 : static Query *
486 479180 : expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
487 : RangeTblEntry *rte, int rt_index,
488 : Relation relation)
489 : {
490 : TupleDesc tupdesc;
491 :
492 : /* Only normal relations can have virtual generated columns */
493 : Assert(rte->rtekind == RTE_RELATION);
494 :
495 479180 : tupdesc = RelationGetDescr(relation);
496 479180 : if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
497 : {
498 1066 : List *tlist = NIL;
499 : pullup_replace_vars_context rvcontext;
500 :
501 4090 : for (int i = 0; i < tupdesc->natts; i++)
502 : {
503 3024 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
504 : TargetEntry *tle;
505 :
506 3024 : if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
507 : {
508 : Node *defexpr;
509 :
510 1408 : defexpr = build_generation_expression(relation, i + 1);
511 1408 : ChangeVarNodes(defexpr, 1, rt_index, 0);
512 :
513 1408 : tle = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
514 1408 : tlist = lappend(tlist, tle);
515 : }
516 : else
517 : {
518 : Var *var;
519 :
520 1616 : var = makeVar(rt_index,
521 1616 : i + 1,
522 : attr->atttypid,
523 : attr->atttypmod,
524 : attr->attcollation,
525 : 0);
526 :
527 1616 : tle = makeTargetEntry((Expr *) var, i + 1, 0, false);
528 1616 : tlist = lappend(tlist, tle);
529 : }
530 : }
531 :
532 : Assert(list_length(tlist) > 0);
533 : Assert(!rte->lateral);
534 :
535 : /*
536 : * The relation's targetlist items are now in the appropriate form to
537 : * insert into the query, except that we may need to wrap them in
538 : * PlaceHolderVars. Set up required context data for
539 : * pullup_replace_vars.
540 : */
541 1066 : rvcontext.root = root;
542 1066 : rvcontext.targetlist = tlist;
543 1066 : rvcontext.target_rte = rte;
544 1066 : rvcontext.result_relation = parse->resultRelation;
545 : /* won't need these values */
546 1066 : rvcontext.relids = NULL;
547 1066 : rvcontext.nullinfo = NULL;
548 : /* pass NULL for outer_hasSubLinks */
549 1066 : rvcontext.outer_hasSubLinks = NULL;
550 1066 : rvcontext.varno = rt_index;
551 : /* this flag will be set below, if needed */
552 1066 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
553 : /* initialize cache array with indexes 0 .. length(tlist) */
554 1066 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
555 : sizeof(Node *));
556 :
557 : /*
558 : * If the query uses grouping sets, we need a PlaceHolderVar for each
559 : * expression of the relation's targetlist items. (See comments in
560 : * pull_up_simple_subquery().)
561 : */
562 1066 : if (parse->groupingSets)
563 12 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
564 :
565 : /*
566 : * Apply pullup variable replacement throughout the query tree.
567 : */
568 1066 : parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
569 : }
570 :
571 479180 : return parse;
572 : }
573 :
574 : /*
575 : * replace_empty_jointree
576 : * If the Query's jointree is empty, replace it with a dummy RTE_RESULT
577 : * relation.
578 : *
579 : * By doing this, we can avoid a bunch of corner cases that formerly existed
580 : * for SELECTs with omitted FROM clauses. An example is that a subquery
581 : * with empty jointree previously could not be pulled up, because that would
582 : * have resulted in an empty relid set, making the subquery not uniquely
583 : * identifiable for join or PlaceHolderVar processing.
584 : *
585 : * Unlike most other functions in this file, this function doesn't recurse;
586 : * we rely on other processing to invoke it on sub-queries at suitable times.
587 : */
588 : void
589 571654 : replace_empty_jointree(Query *parse)
590 : {
591 : RangeTblEntry *rte;
592 : Index rti;
593 : RangeTblRef *rtr;
594 :
595 : /* Nothing to do if jointree is already nonempty */
596 571654 : if (parse->jointree->fromlist != NIL)
597 370544 : return;
598 :
599 : /* We mustn't change it in the top level of a setop tree, either */
600 207690 : if (parse->setOperations)
601 6580 : return;
602 :
603 : /* Create suitable RTE */
604 201110 : rte = makeNode(RangeTblEntry);
605 201110 : rte->rtekind = RTE_RESULT;
606 201110 : rte->eref = makeAlias("*RESULT*", NIL);
607 :
608 : /* Add it to rangetable */
609 201110 : parse->rtable = lappend(parse->rtable, rte);
610 201110 : rti = list_length(parse->rtable);
611 :
612 : /* And jam a reference into the jointree */
613 201110 : rtr = makeNode(RangeTblRef);
614 201110 : rtr->rtindex = rti;
615 201110 : parse->jointree->fromlist = list_make1(rtr);
616 : }
617 :
618 : /*
619 : * pull_up_sublinks
620 : * Attempt to pull up ANY and EXISTS SubLinks to be treated as
621 : * semijoins or anti-semijoins.
622 : *
623 : * A clause "foo op ANY (sub-SELECT)" can be processed by pulling the
624 : * sub-SELECT up to become a rangetable entry and treating the implied
625 : * comparisons as quals of a semijoin. However, this optimization *only*
626 : * works at the top level of WHERE or a JOIN/ON clause, because we cannot
627 : * distinguish whether the ANY ought to return FALSE or NULL in cases
628 : * involving NULL inputs. Also, in an outer join's ON clause we can only
629 : * do this if the sublink is degenerate (ie, references only the nullable
630 : * side of the join). In that case it is legal to push the semijoin
631 : * down into the nullable side of the join. If the sublink references any
632 : * nonnullable-side variables then it would have to be evaluated as part
633 : * of the outer join, which makes things way too complicated.
634 : *
635 : * Under similar conditions, EXISTS and NOT EXISTS clauses can be handled
636 : * by pulling up the sub-SELECT and creating a semijoin or anti-semijoin.
637 : *
638 : * This routine searches for such clauses and does the necessary parsetree
639 : * transformations if any are found.
640 : *
641 : * This routine has to run before preprocess_expression(), so the quals
642 : * clauses are not yet reduced to implicit-AND format, and are not guaranteed
643 : * to be AND/OR-flat either. That means we need to recursively search through
644 : * explicit AND clauses. We stop as soon as we hit a non-AND item.
645 : */
646 : void
647 38684 : pull_up_sublinks(PlannerInfo *root)
648 : {
649 : Node *jtnode;
650 : Relids relids;
651 :
652 : /* Begin recursion through the jointree */
653 38684 : jtnode = pull_up_sublinks_jointree_recurse(root,
654 38684 : (Node *) root->parse->jointree,
655 : &relids);
656 :
657 : /*
658 : * root->parse->jointree must always be a FromExpr, so insert a dummy one
659 : * if we got a bare RangeTblRef or JoinExpr out of the recursion.
660 : */
661 38684 : if (IsA(jtnode, FromExpr))
662 30908 : root->parse->jointree = (FromExpr *) jtnode;
663 : else
664 7776 : root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
665 38684 : }
666 :
667 : /*
668 : * Recurse through jointree nodes for pull_up_sublinks()
669 : *
670 : * In addition to returning the possibly-modified jointree node, we return
671 : * a relids set of the contained rels into *relids.
672 : */
673 : static Node *
674 129638 : pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
675 : Relids *relids)
676 : {
677 : /* Since this function recurses, it could be driven to stack overflow. */
678 129638 : check_stack_depth();
679 :
680 129638 : if (jtnode == NULL)
681 : {
682 0 : *relids = NULL;
683 : }
684 129638 : else if (IsA(jtnode, RangeTblRef))
685 : {
686 70462 : int varno = ((RangeTblRef *) jtnode)->rtindex;
687 :
688 70462 : *relids = bms_make_singleton(varno);
689 : /* jtnode is returned unmodified */
690 : }
691 59176 : else if (IsA(jtnode, FromExpr))
692 : {
693 38912 : FromExpr *f = (FromExpr *) jtnode;
694 38912 : List *newfromlist = NIL;
695 38912 : Relids frelids = NULL;
696 : FromExpr *newf;
697 : Node *jtlink;
698 : ListCell *l;
699 :
700 : /* First, recurse to process children and collect their relids */
701 81340 : foreach(l, f->fromlist)
702 : {
703 : Node *newchild;
704 : Relids childrelids;
705 :
706 42428 : newchild = pull_up_sublinks_jointree_recurse(root,
707 42428 : lfirst(l),
708 : &childrelids);
709 42428 : newfromlist = lappend(newfromlist, newchild);
710 42428 : frelids = bms_join(frelids, childrelids);
711 : }
712 : /* Build the replacement FromExpr; no quals yet */
713 38912 : newf = makeFromExpr(newfromlist, NULL);
714 : /* Set up a link representing the rebuilt jointree */
715 38912 : jtlink = (Node *) newf;
716 : /* Now process qual --- all children are available for use */
717 38912 : newf->quals = pull_up_sublinks_qual_recurse(root, f->quals,
718 : &jtlink, frelids,
719 : NULL, NULL);
720 :
721 : /*
722 : * Note that the result will be either newf, or a stack of JoinExprs
723 : * with newf at the base. We rely on subsequent optimization steps to
724 : * flatten this and rearrange the joins as needed.
725 : *
726 : * Although we could include the pulled-up subqueries in the returned
727 : * relids, there's no need since upper quals couldn't refer to their
728 : * outputs anyway.
729 : */
730 38912 : *relids = frelids;
731 38912 : jtnode = jtlink;
732 : }
733 20264 : else if (IsA(jtnode, JoinExpr))
734 : {
735 : JoinExpr *j;
736 : Relids leftrelids;
737 : Relids rightrelids;
738 : Node *jtlink;
739 :
740 : /*
741 : * Make a modifiable copy of join node, but don't bother copying its
742 : * subnodes (yet).
743 : */
744 20264 : j = (JoinExpr *) palloc(sizeof(JoinExpr));
745 20264 : memcpy(j, jtnode, sizeof(JoinExpr));
746 20264 : jtlink = (Node *) j;
747 :
748 : /* Recurse to process children and collect their relids */
749 20264 : j->larg = pull_up_sublinks_jointree_recurse(root, j->larg,
750 : &leftrelids);
751 20264 : j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg,
752 : &rightrelids);
753 :
754 : /*
755 : * Now process qual, showing appropriate child relids as available,
756 : * and attach any pulled-up jointree items at the right place. In the
757 : * inner-join case we put new JoinExprs above the existing one (much
758 : * as for a FromExpr-style join). In outer-join cases the new
759 : * JoinExprs must go into the nullable side of the outer join. The
760 : * point of the available_rels machinations is to ensure that we only
761 : * pull up quals for which that's okay.
762 : *
763 : * We don't expect to see any pre-existing JOIN_SEMI, JOIN_ANTI,
764 : * JOIN_RIGHT_SEMI, or JOIN_RIGHT_ANTI jointypes here.
765 : */
766 20264 : switch (j->jointype)
767 : {
768 9134 : case JOIN_INNER:
769 9134 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
770 : &jtlink,
771 : bms_union(leftrelids,
772 : rightrelids),
773 : NULL, NULL);
774 9134 : break;
775 11022 : case JOIN_LEFT:
776 11022 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
777 : &j->rarg,
778 : rightrelids,
779 : NULL, NULL);
780 11022 : break;
781 12 : case JOIN_FULL:
782 : /* can't do anything with full-join quals */
783 12 : break;
784 96 : case JOIN_RIGHT:
785 96 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
786 : &j->larg,
787 : leftrelids,
788 : NULL, NULL);
789 96 : break;
790 0 : default:
791 0 : elog(ERROR, "unrecognized join type: %d",
792 : (int) j->jointype);
793 : break;
794 : }
795 :
796 : /*
797 : * Although we could include the pulled-up subqueries in the returned
798 : * relids, there's no need since upper quals couldn't refer to their
799 : * outputs anyway. But we *do* need to include the join's own rtindex
800 : * because we haven't yet collapsed join alias variables, so upper
801 : * levels would mistakenly think they couldn't use references to this
802 : * join.
803 : */
804 20264 : *relids = bms_join(leftrelids, rightrelids);
805 20264 : if (j->rtindex)
806 20264 : *relids = bms_add_member(*relids, j->rtindex);
807 20264 : jtnode = jtlink;
808 : }
809 : else
810 0 : elog(ERROR, "unrecognized node type: %d",
811 : (int) nodeTag(jtnode));
812 129638 : return jtnode;
813 : }
814 :
815 : /*
816 : * Recurse through top-level qual nodes for pull_up_sublinks()
817 : *
818 : * jtlink1 points to the link in the jointree where any new JoinExprs should
819 : * be inserted if they reference available_rels1 (i.e., available_rels1
820 : * denotes the relations present underneath jtlink1). Optionally, jtlink2 can
821 : * point to a second link where new JoinExprs should be inserted if they
822 : * reference available_rels2 (pass NULL for both those arguments if not used).
823 : * Note that SubLinks referencing both sets of variables cannot be optimized.
824 : * If we find multiple pull-up-able SubLinks, they'll get stacked onto jtlink1
825 : * and/or jtlink2 in the order we encounter them. We rely on subsequent
826 : * optimization to rearrange the stack if appropriate.
827 : *
828 : * Returns the replacement qual node, or NULL if the qual should be removed.
829 : */
830 : static Node *
831 121710 : pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
832 : Node **jtlink1, Relids available_rels1,
833 : Node **jtlink2, Relids available_rels2)
834 : {
835 121710 : if (node == NULL)
836 7464 : return NULL;
837 114246 : if (IsA(node, SubLink))
838 : {
839 5638 : SubLink *sublink = (SubLink *) node;
840 : JoinExpr *j;
841 : Relids child_rels;
842 :
843 : /* Is it a convertible ANY or EXISTS clause? */
844 5638 : if (sublink->subLinkType == ANY_SUBLINK)
845 : {
846 : ScalarArrayOpExpr *saop;
847 :
848 4666 : if ((saop = convert_VALUES_to_ANY(root,
849 : sublink->testexpr,
850 4666 : (Query *) sublink->subselect)) != NULL)
851 :
852 : /*
853 : * The VALUES sequence was simplified. Nothing more to do
854 : * here.
855 : */
856 84 : return (Node *) saop;
857 :
858 4582 : if ((j = convert_ANY_sublink_to_join(root, sublink,
859 : available_rels1)) != NULL)
860 : {
861 : /* Yes; insert the new join node into the join tree */
862 4476 : j->larg = *jtlink1;
863 4476 : *jtlink1 = (Node *) j;
864 : /* Recursively process pulled-up jointree nodes */
865 4476 : j->rarg = pull_up_sublinks_jointree_recurse(root,
866 : j->rarg,
867 : &child_rels);
868 :
869 : /*
870 : * Now recursively process the pulled-up quals. Any inserted
871 : * joins can get stacked onto either j->larg or j->rarg,
872 : * depending on which rels they reference.
873 : */
874 4476 : j->quals = pull_up_sublinks_qual_recurse(root,
875 : j->quals,
876 : &j->larg,
877 : available_rels1,
878 : &j->rarg,
879 : child_rels);
880 : /* Return NULL representing constant TRUE */
881 4476 : return NULL;
882 : }
883 112 : if (available_rels2 != NULL &&
884 6 : (j = convert_ANY_sublink_to_join(root, sublink,
885 : available_rels2)) != NULL)
886 : {
887 : /* Yes; insert the new join node into the join tree */
888 0 : j->larg = *jtlink2;
889 0 : *jtlink2 = (Node *) j;
890 : /* Recursively process pulled-up jointree nodes */
891 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
892 : j->rarg,
893 : &child_rels);
894 :
895 : /*
896 : * Now recursively process the pulled-up quals. Any inserted
897 : * joins can get stacked onto either j->larg or j->rarg,
898 : * depending on which rels they reference.
899 : */
900 0 : j->quals = pull_up_sublinks_qual_recurse(root,
901 : j->quals,
902 : &j->larg,
903 : available_rels2,
904 : &j->rarg,
905 : child_rels);
906 : /* Return NULL representing constant TRUE */
907 0 : return NULL;
908 : }
909 : }
910 972 : else if (sublink->subLinkType == EXISTS_SUBLINK)
911 : {
912 912 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, false,
913 : available_rels1)) != NULL)
914 : {
915 : /* Yes; insert the new join node into the join tree */
916 748 : j->larg = *jtlink1;
917 748 : *jtlink1 = (Node *) j;
918 : /* Recursively process pulled-up jointree nodes */
919 748 : j->rarg = pull_up_sublinks_jointree_recurse(root,
920 : j->rarg,
921 : &child_rels);
922 :
923 : /*
924 : * Now recursively process the pulled-up quals. Any inserted
925 : * joins can get stacked onto either j->larg or j->rarg,
926 : * depending on which rels they reference.
927 : */
928 748 : j->quals = pull_up_sublinks_qual_recurse(root,
929 : j->quals,
930 : &j->larg,
931 : available_rels1,
932 : &j->rarg,
933 : child_rels);
934 : /* Return NULL representing constant TRUE */
935 748 : return NULL;
936 : }
937 196 : if (available_rels2 != NULL &&
938 32 : (j = convert_EXISTS_sublink_to_join(root, sublink, false,
939 : available_rels2)) != NULL)
940 : {
941 : /* Yes; insert the new join node into the join tree */
942 32 : j->larg = *jtlink2;
943 32 : *jtlink2 = (Node *) j;
944 : /* Recursively process pulled-up jointree nodes */
945 32 : j->rarg = pull_up_sublinks_jointree_recurse(root,
946 : j->rarg,
947 : &child_rels);
948 :
949 : /*
950 : * Now recursively process the pulled-up quals. Any inserted
951 : * joins can get stacked onto either j->larg or j->rarg,
952 : * depending on which rels they reference.
953 : */
954 32 : j->quals = pull_up_sublinks_qual_recurse(root,
955 : j->quals,
956 : &j->larg,
957 : available_rels2,
958 : &j->rarg,
959 : child_rels);
960 : /* Return NULL representing constant TRUE */
961 32 : return NULL;
962 : }
963 : }
964 : /* Else return it unmodified */
965 298 : return node;
966 : }
967 108608 : if (is_notclause(node))
968 : {
969 : /* If the immediate argument of NOT is EXISTS, try to convert */
970 7446 : SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
971 : JoinExpr *j;
972 : Relids child_rels;
973 :
974 7446 : if (sublink && IsA(sublink, SubLink))
975 : {
976 2852 : if (sublink->subLinkType == EXISTS_SUBLINK)
977 : {
978 2756 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, true,
979 : available_rels1)) != NULL)
980 : {
981 : /* Yes; insert the new join node into the join tree */
982 2742 : j->larg = *jtlink1;
983 2742 : *jtlink1 = (Node *) j;
984 : /* Recursively process pulled-up jointree nodes */
985 2742 : j->rarg = pull_up_sublinks_jointree_recurse(root,
986 : j->rarg,
987 : &child_rels);
988 :
989 : /*
990 : * Now recursively process the pulled-up quals. Because
991 : * we are underneath a NOT, we can't pull up sublinks that
992 : * reference the left-hand stuff, but it's still okay to
993 : * pull up sublinks referencing j->rarg.
994 : */
995 2742 : j->quals = pull_up_sublinks_qual_recurse(root,
996 : j->quals,
997 : &j->rarg,
998 : child_rels,
999 : NULL, NULL);
1000 : /* Return NULL representing constant TRUE */
1001 2742 : return NULL;
1002 : }
1003 14 : if (available_rels2 != NULL &&
1004 0 : (j = convert_EXISTS_sublink_to_join(root, sublink, true,
1005 : available_rels2)) != NULL)
1006 : {
1007 : /* Yes; insert the new join node into the join tree */
1008 0 : j->larg = *jtlink2;
1009 0 : *jtlink2 = (Node *) j;
1010 : /* Recursively process pulled-up jointree nodes */
1011 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1012 : j->rarg,
1013 : &child_rels);
1014 :
1015 : /*
1016 : * Now recursively process the pulled-up quals. Because
1017 : * we are underneath a NOT, we can't pull up sublinks that
1018 : * reference the left-hand stuff, but it's still okay to
1019 : * pull up sublinks referencing j->rarg.
1020 : */
1021 0 : j->quals = pull_up_sublinks_qual_recurse(root,
1022 : j->quals,
1023 : &j->rarg,
1024 : child_rels,
1025 : NULL, NULL);
1026 : /* Return NULL representing constant TRUE */
1027 0 : return NULL;
1028 : }
1029 : }
1030 : }
1031 : /* Else return it unmodified */
1032 4704 : return node;
1033 : }
1034 101162 : if (is_andclause(node))
1035 : {
1036 : /* Recurse into AND clause */
1037 18968 : List *newclauses = NIL;
1038 : ListCell *l;
1039 :
1040 73516 : foreach(l, ((BoolExpr *) node)->args)
1041 : {
1042 54548 : Node *oldclause = (Node *) lfirst(l);
1043 : Node *newclause;
1044 :
1045 54548 : newclause = pull_up_sublinks_qual_recurse(root,
1046 : oldclause,
1047 : jtlink1,
1048 : available_rels1,
1049 : jtlink2,
1050 : available_rels2);
1051 54548 : if (newclause)
1052 48914 : newclauses = lappend(newclauses, newclause);
1053 : }
1054 : /* We might have got back fewer clauses than we started with */
1055 18968 : if (newclauses == NIL)
1056 124 : return NULL;
1057 18844 : else if (list_length(newclauses) == 1)
1058 1140 : return (Node *) linitial(newclauses);
1059 : else
1060 17704 : return (Node *) make_andclause(newclauses);
1061 : }
1062 : /* Stop if not an AND */
1063 82194 : return node;
1064 : }
1065 :
1066 : /*
1067 : * preprocess_function_rtes
1068 : * Constant-simplify any FUNCTION RTEs in the FROM clause, and then
1069 : * attempt to "inline" any that are set-returning functions.
1070 : *
1071 : * If an RTE_FUNCTION rtable entry invokes a set-returning function that
1072 : * contains just a simple SELECT, we can convert the rtable entry to an
1073 : * RTE_SUBQUERY entry exposing the SELECT directly. This is especially
1074 : * useful if the subquery can then be "pulled up" for further optimization,
1075 : * but we do it even if not, to reduce executor overhead.
1076 : *
1077 : * This has to be done before we have started to do any optimization of
1078 : * subqueries, else any such steps wouldn't get applied to subqueries
1079 : * obtained via inlining. However, we do it after pull_up_sublinks
1080 : * so that we can inline any functions used in SubLink subselects.
1081 : *
1082 : * The reason for applying const-simplification at this stage is that
1083 : * (a) we'd need to do it anyway to inline a SRF, and (b) by doing it now,
1084 : * we can be sure that pull_up_constant_function() will see constants
1085 : * if there are constants to be seen. This approach also guarantees
1086 : * that every FUNCTION RTE has been const-simplified, allowing planner.c's
1087 : * preprocess_expression() to skip doing it again.
1088 : *
1089 : * Like most of the planner, this feels free to scribble on its input data
1090 : * structure.
1091 : */
1092 : void
1093 568088 : preprocess_function_rtes(PlannerInfo *root)
1094 : {
1095 : ListCell *rt;
1096 :
1097 1478142 : foreach(rt, root->parse->rtable)
1098 : {
1099 910060 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
1100 :
1101 910060 : if (rte->rtekind == RTE_FUNCTION)
1102 : {
1103 : Query *funcquery;
1104 :
1105 : /* Apply const-simplification */
1106 51940 : rte->functions = (List *)
1107 51940 : eval_const_expressions(root, (Node *) rte->functions);
1108 :
1109 : /* Check safety of expansion, and expand if possible */
1110 51940 : funcquery = inline_set_returning_function(root, rte);
1111 51934 : if (funcquery)
1112 : {
1113 : /* Successful expansion, convert the RTE to a subquery */
1114 222 : rte->rtekind = RTE_SUBQUERY;
1115 222 : rte->subquery = funcquery;
1116 222 : rte->security_barrier = false;
1117 :
1118 : /*
1119 : * Clear fields that should not be set in a subquery RTE.
1120 : * However, we leave rte->functions filled in for the moment,
1121 : * in case makeWholeRowVar needs to consult it. We'll clear
1122 : * it in setrefs.c (see add_rte_to_flat_rtable) so that this
1123 : * abuse of the data structure doesn't escape the planner.
1124 : */
1125 222 : rte->funcordinality = false;
1126 : }
1127 : }
1128 : }
1129 568082 : }
1130 :
1131 : /*
1132 : * pull_up_subqueries
1133 : * Look for subqueries in the rangetable that can be pulled up into
1134 : * the parent query. If the subquery has no special features like
1135 : * grouping/aggregation then we can merge it into the parent's jointree.
1136 : * Also, subqueries that are simple UNION ALL structures can be
1137 : * converted into "append relations".
1138 : */
1139 : void
1140 568082 : pull_up_subqueries(PlannerInfo *root)
1141 : {
1142 : /* Top level of jointree must always be a FromExpr */
1143 : Assert(IsA(root->parse->jointree, FromExpr));
1144 : /* Recursion starts with no containing join nor appendrel */
1145 1136158 : root->parse->jointree = (FromExpr *)
1146 568082 : pull_up_subqueries_recurse(root, (Node *) root->parse->jointree,
1147 : NULL, NULL);
1148 : /* We should still have a FromExpr */
1149 : Assert(IsA(root->parse->jointree, FromExpr));
1150 568076 : }
1151 :
1152 : /*
1153 : * pull_up_subqueries_recurse
1154 : * Recursive guts of pull_up_subqueries.
1155 : *
1156 : * This recursively processes the jointree and returns a modified jointree.
1157 : *
1158 : * If this jointree node is within either side of an outer join, then
1159 : * lowest_outer_join references the lowest such JoinExpr node; otherwise
1160 : * it is NULL. We use this to constrain the effects of LATERAL subqueries.
1161 : *
1162 : * If we are looking at a member subquery of an append relation,
1163 : * containing_appendrel describes that relation; else it is NULL.
1164 : * This forces use of the PlaceHolderVar mechanism for all non-Var targetlist
1165 : * items, and puts some additional restrictions on what can be pulled up.
1166 : *
1167 : * A tricky aspect of this code is that if we pull up a subquery we have
1168 : * to replace Vars that reference the subquery's outputs throughout the
1169 : * parent query, including quals attached to jointree nodes above the one
1170 : * we are currently processing! We handle this by being careful to maintain
1171 : * validity of the jointree structure while recursing, in the following sense:
1172 : * whenever we recurse, all qual expressions in the tree must be reachable
1173 : * from the top level, in case the recursive call needs to modify them.
1174 : *
1175 : * Notice also that we can't turn pullup_replace_vars loose on the whole
1176 : * jointree, because it'd return a mutated copy of the tree; we have to
1177 : * invoke it just on the quals, instead. This behavior is what makes it
1178 : * reasonable to pass lowest_outer_join as a pointer rather than some
1179 : * more-indirect way of identifying the lowest OJ. Likewise, we don't
1180 : * replace append_rel_list members but only their substructure, so the
1181 : * containing_appendrel reference is safe to use.
1182 : */
1183 : static Node *
1184 1407390 : pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
1185 : JoinExpr *lowest_outer_join,
1186 : AppendRelInfo *containing_appendrel)
1187 : {
1188 : /* Since this function recurses, it could be driven to stack overflow. */
1189 1407390 : check_stack_depth();
1190 : /* Also, since it's a bit expensive, let's check for query cancel. */
1191 1407390 : CHECK_FOR_INTERRUPTS();
1192 :
1193 : Assert(jtnode != NULL);
1194 1407390 : if (IsA(jtnode, RangeTblRef))
1195 : {
1196 728476 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1197 728476 : RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
1198 :
1199 : /*
1200 : * Is this a subquery RTE, and if so, is the subquery simple enough to
1201 : * pull up?
1202 : *
1203 : * If we are looking at an append-relation member, we can't pull it up
1204 : * unless is_safe_append_member says so.
1205 : */
1206 787330 : if (rte->rtekind == RTE_SUBQUERY &&
1207 102080 : is_simple_subquery(root, rte->subquery, rte, lowest_outer_join) &&
1208 12384 : (containing_appendrel == NULL ||
1209 12384 : is_safe_append_member(rte->subquery)))
1210 37288 : return pull_up_simple_subquery(root, jtnode, rte,
1211 : lowest_outer_join,
1212 : containing_appendrel);
1213 :
1214 : /*
1215 : * Alternatively, is it a simple UNION ALL subquery? If so, flatten
1216 : * into an "append relation".
1217 : *
1218 : * It's safe to do this regardless of whether this query is itself an
1219 : * appendrel member. (If you're thinking we should try to flatten the
1220 : * two levels of appendrel together, you're right; but we handle that
1221 : * in set_append_rel_pathlist, not here.)
1222 : */
1223 712754 : if (rte->rtekind == RTE_SUBQUERY &&
1224 21566 : is_simple_union_all(rte->subquery))
1225 4804 : return pull_up_simple_union_all(root, jtnode, rte);
1226 :
1227 : /*
1228 : * Or perhaps it's a simple VALUES RTE?
1229 : *
1230 : * We don't allow VALUES pullup below an outer join nor into an
1231 : * appendrel (such cases are impossible anyway at the moment).
1232 : */
1233 686384 : if (rte->rtekind == RTE_VALUES &&
1234 12774 : lowest_outer_join == NULL &&
1235 12774 : containing_appendrel == NULL &&
1236 12774 : is_simple_values(root, rte))
1237 4504 : return pull_up_simple_values(root, jtnode, rte);
1238 :
1239 : /*
1240 : * Or perhaps it's a FUNCTION RTE that we could inline?
1241 : */
1242 681880 : if (rte->rtekind == RTE_FUNCTION)
1243 51712 : return pull_up_constant_function(root, jtnode, rte,
1244 : containing_appendrel);
1245 :
1246 : /* Otherwise, do nothing at this node. */
1247 : }
1248 678914 : else if (IsA(jtnode, FromExpr))
1249 : {
1250 577784 : FromExpr *f = (FromExpr *) jtnode;
1251 : ListCell *l;
1252 :
1253 : Assert(containing_appendrel == NULL);
1254 : /* Recursively transform all the child nodes */
1255 1199288 : foreach(l, f->fromlist)
1256 : {
1257 621510 : lfirst(l) = pull_up_subqueries_recurse(root, lfirst(l),
1258 : lowest_outer_join,
1259 : NULL);
1260 : }
1261 : }
1262 101130 : else if (IsA(jtnode, JoinExpr))
1263 : {
1264 101130 : JoinExpr *j = (JoinExpr *) jtnode;
1265 :
1266 : Assert(containing_appendrel == NULL);
1267 : /* Recurse, being careful to tell myself when inside outer join */
1268 101130 : switch (j->jointype)
1269 : {
1270 44932 : case JOIN_INNER:
1271 44932 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1272 : lowest_outer_join,
1273 : NULL);
1274 44932 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1275 : lowest_outer_join,
1276 : NULL);
1277 44932 : break;
1278 53906 : case JOIN_LEFT:
1279 : case JOIN_SEMI:
1280 : case JOIN_ANTI:
1281 53906 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1282 : j,
1283 : NULL);
1284 53906 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1285 : j,
1286 : NULL);
1287 53906 : break;
1288 1090 : case JOIN_FULL:
1289 1090 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1290 : j,
1291 : NULL);
1292 1090 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1293 : j,
1294 : NULL);
1295 1090 : break;
1296 1202 : case JOIN_RIGHT:
1297 1202 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1298 : j,
1299 : NULL);
1300 1202 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1301 : j,
1302 : NULL);
1303 1202 : break;
1304 0 : default:
1305 0 : elog(ERROR, "unrecognized join type: %d",
1306 : (int) j->jointype);
1307 : break;
1308 : }
1309 : }
1310 : else
1311 0 : elog(ERROR, "unrecognized node type: %d",
1312 : (int) nodeTag(jtnode));
1313 1309076 : return jtnode;
1314 : }
1315 :
1316 : /*
1317 : * pull_up_simple_subquery
1318 : * Attempt to pull up a single simple subquery.
1319 : *
1320 : * jtnode is a RangeTblRef that has been tentatively identified as a simple
1321 : * subquery by pull_up_subqueries. We return the replacement jointree node,
1322 : * or jtnode itself if we determine that the subquery can't be pulled up
1323 : * after all.
1324 : *
1325 : * rte is the RangeTblEntry referenced by jtnode. Remaining parameters are
1326 : * as for pull_up_subqueries_recurse.
1327 : */
1328 : static Node *
1329 37288 : pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
1330 : JoinExpr *lowest_outer_join,
1331 : AppendRelInfo *containing_appendrel)
1332 : {
1333 37288 : Query *parse = root->parse;
1334 37288 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1335 : Query *subquery;
1336 : PlannerInfo *subroot;
1337 : int rtoffset;
1338 : pullup_replace_vars_context rvcontext;
1339 : ListCell *lc;
1340 :
1341 : /*
1342 : * Make a modifiable copy of the subquery to hack on, so that the RTE will
1343 : * be left unchanged in case we decide below that we can't pull it up
1344 : * after all.
1345 : */
1346 37288 : subquery = copyObject(rte->subquery);
1347 :
1348 : /*
1349 : * Create a PlannerInfo data structure for this subquery.
1350 : *
1351 : * NOTE: the next few steps should match the first processing in
1352 : * subquery_planner(). Can we refactor to avoid code duplication, or
1353 : * would that just make things uglier?
1354 : */
1355 37288 : subroot = makeNode(PlannerInfo);
1356 37288 : subroot->parse = subquery;
1357 37288 : subroot->glob = root->glob;
1358 37288 : subroot->query_level = root->query_level;
1359 37288 : subroot->plan_name = root->plan_name;
1360 37288 : subroot->parent_root = root->parent_root;
1361 37288 : subroot->plan_params = NIL;
1362 37288 : subroot->outer_params = NULL;
1363 37288 : subroot->planner_cxt = CurrentMemoryContext;
1364 37288 : subroot->init_plans = NIL;
1365 37288 : subroot->cte_plan_ids = NIL;
1366 37288 : subroot->multiexpr_params = NIL;
1367 37288 : subroot->join_domains = NIL;
1368 37288 : subroot->eq_classes = NIL;
1369 37288 : subroot->ec_merging_done = false;
1370 37288 : subroot->last_rinfo_serial = 0;
1371 37288 : subroot->all_result_relids = NULL;
1372 37288 : subroot->leaf_result_relids = NULL;
1373 37288 : subroot->append_rel_list = NIL;
1374 37288 : subroot->row_identity_vars = NIL;
1375 37288 : subroot->rowMarks = NIL;
1376 37288 : memset(subroot->upper_rels, 0, sizeof(subroot->upper_rels));
1377 37288 : memset(subroot->upper_targets, 0, sizeof(subroot->upper_targets));
1378 37288 : subroot->processed_groupClause = NIL;
1379 37288 : subroot->processed_distinctClause = NIL;
1380 37288 : subroot->processed_tlist = NIL;
1381 37288 : subroot->update_colnos = NIL;
1382 37288 : subroot->grouping_map = NULL;
1383 37288 : subroot->minmax_aggs = NIL;
1384 37288 : subroot->qual_security_level = 0;
1385 37288 : subroot->placeholdersFrozen = false;
1386 37288 : subroot->hasRecursion = false;
1387 37288 : subroot->assumeReplanning = false;
1388 37288 : subroot->wt_param_id = -1;
1389 37288 : subroot->non_recursive_path = NULL;
1390 : /* We don't currently need a top JoinDomain for the subroot */
1391 :
1392 : /* No CTEs to worry about */
1393 : Assert(subquery->cteList == NIL);
1394 :
1395 : /*
1396 : * Scan the rangetable for relation RTEs and retrieve the necessary
1397 : * catalog information for each relation. Using this information, clear
1398 : * the inh flag for any relation that has no children, collect not-null
1399 : * attribute numbers for any relation that has column not-null
1400 : * constraints, and expand virtual generated columns for any relation that
1401 : * contains them.
1402 : */
1403 37288 : subquery = subroot->parse = preprocess_relation_rtes(subroot);
1404 :
1405 : /*
1406 : * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
1407 : * that we don't need so many special cases to deal with that situation.
1408 : */
1409 37288 : replace_empty_jointree(subquery);
1410 :
1411 : /*
1412 : * Pull up any SubLinks within the subquery's quals, so that we don't
1413 : * leave unoptimized SubLinks behind.
1414 : */
1415 37288 : if (subquery->hasSubLinks)
1416 2384 : pull_up_sublinks(subroot);
1417 :
1418 : /*
1419 : * Similarly, preprocess its function RTEs to inline any set-returning
1420 : * functions in its rangetable.
1421 : */
1422 37288 : preprocess_function_rtes(subroot);
1423 :
1424 : /*
1425 : * Recursively pull up the subquery's subqueries, so that
1426 : * pull_up_subqueries' processing is complete for its jointree and
1427 : * rangetable.
1428 : *
1429 : * Note: it's okay that the subquery's recursion starts with NULL for
1430 : * containing-join info, even if we are within an outer join in the upper
1431 : * query; the lower query starts with a clean slate for outer-join
1432 : * semantics. Likewise, we needn't pass down appendrel state.
1433 : */
1434 37288 : pull_up_subqueries(subroot);
1435 :
1436 : /*
1437 : * Now we must recheck whether the subquery is still simple enough to pull
1438 : * up. If not, abandon processing it.
1439 : *
1440 : * We don't really need to recheck all the conditions involved, but it's
1441 : * easier just to keep this "if" looking the same as the one in
1442 : * pull_up_subqueries_recurse.
1443 : */
1444 37288 : if (is_simple_subquery(root, subquery, rte, lowest_outer_join) &&
1445 6446 : (containing_appendrel == NULL || is_safe_append_member(subquery)))
1446 : {
1447 : /* good to go */
1448 : }
1449 : else
1450 : {
1451 : /*
1452 : * Give up, return unmodified RangeTblRef.
1453 : *
1454 : * Note: The work we just did will be redone when the subquery gets
1455 : * planned on its own. Perhaps we could avoid that by storing the
1456 : * modified subquery back into the rangetable, but I'm not gonna risk
1457 : * it now.
1458 : */
1459 228 : return jtnode;
1460 : }
1461 :
1462 : /*
1463 : * We must flatten any join alias Vars in the subquery's targetlist,
1464 : * because pulling up the subquery's subqueries might have changed their
1465 : * expansions into arbitrary expressions, which could affect
1466 : * pullup_replace_vars' decisions about whether PlaceHolderVar wrappers
1467 : * are needed for tlist entries. (Likely it'd be better to do
1468 : * flatten_join_alias_vars on the whole query tree at some earlier stage,
1469 : * maybe even in the rewriter; but for now let's just fix this case here.)
1470 : */
1471 37060 : subquery->targetList = (List *)
1472 37060 : flatten_join_alias_vars(subroot, subroot->parse,
1473 37060 : (Node *) subquery->targetList);
1474 :
1475 : /*
1476 : * Adjust level-0 varnos in subquery so that we can append its rangetable
1477 : * to upper query's. We have to fix the subquery's append_rel_list as
1478 : * well.
1479 : */
1480 37060 : rtoffset = list_length(parse->rtable);
1481 37060 : OffsetVarNodes((Node *) subquery, rtoffset, 0);
1482 37060 : OffsetVarNodes((Node *) subroot->append_rel_list, rtoffset, 0);
1483 :
1484 : /*
1485 : * Upper-level vars in subquery are now one level closer to their parent
1486 : * than before.
1487 : */
1488 37060 : IncrementVarSublevelsUp((Node *) subquery, -1, 1);
1489 37060 : IncrementVarSublevelsUp((Node *) subroot->append_rel_list, -1, 1);
1490 :
1491 : /*
1492 : * The subquery's targetlist items are now in the appropriate form to
1493 : * insert into the top query, except that we may need to wrap them in
1494 : * PlaceHolderVars. Set up required context data for pullup_replace_vars.
1495 : * (Note that we should include the subquery's inner joins in relids,
1496 : * since it may include join alias vars referencing them.)
1497 : */
1498 37060 : rvcontext.root = root;
1499 37060 : rvcontext.targetlist = subquery->targetList;
1500 37060 : rvcontext.target_rte = rte;
1501 37060 : rvcontext.result_relation = 0;
1502 37060 : if (rte->lateral)
1503 : {
1504 1154 : rvcontext.relids = get_relids_in_jointree((Node *) subquery->jointree,
1505 : true, true);
1506 1154 : rvcontext.nullinfo = get_nullingrels(parse);
1507 : }
1508 : else /* won't need these values */
1509 : {
1510 35906 : rvcontext.relids = NULL;
1511 35906 : rvcontext.nullinfo = NULL;
1512 : }
1513 37060 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1514 37060 : rvcontext.varno = varno;
1515 : /* this flag will be set below, if needed */
1516 37060 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
1517 : /* initialize cache array with indexes 0 .. length(tlist) */
1518 37060 : rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
1519 : sizeof(Node *));
1520 :
1521 : /*
1522 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
1523 : * each expression of the subquery's targetlist items. This ensures that
1524 : * expressions retain their separate identity so that they will match
1525 : * grouping set columns when appropriate. (It'd be sufficient to wrap
1526 : * values used in grouping set columns, and do so only in non-aggregated
1527 : * portions of the tlist and havingQual, but that would require a lot of
1528 : * infrastructure that pullup_replace_vars hasn't currently got.)
1529 : */
1530 37060 : if (parse->groupingSets)
1531 332 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
1532 :
1533 : /*
1534 : * Replace all of the top query's references to the subquery's outputs
1535 : * with copies of the adjusted subtlist items, being careful not to
1536 : * replace any of the jointree structure.
1537 : */
1538 37060 : perform_pullup_replace_vars(root, &rvcontext,
1539 : containing_appendrel);
1540 :
1541 : /*
1542 : * If the subquery had a LATERAL marker, propagate that to any of its
1543 : * child RTEs that could possibly now contain lateral cross-references.
1544 : * The children might or might not contain any actual lateral
1545 : * cross-references, but we have to mark the pulled-up child RTEs so that
1546 : * later planner stages will check for such.
1547 : */
1548 37054 : if (rte->lateral)
1549 : {
1550 2704 : foreach(lc, subquery->rtable)
1551 : {
1552 1550 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(lc);
1553 :
1554 1550 : switch (child_rte->rtekind)
1555 : {
1556 696 : case RTE_RELATION:
1557 696 : if (child_rte->tablesample)
1558 36 : child_rte->lateral = true;
1559 696 : break;
1560 280 : case RTE_SUBQUERY:
1561 : case RTE_FUNCTION:
1562 : case RTE_VALUES:
1563 : case RTE_TABLEFUNC:
1564 280 : child_rte->lateral = true;
1565 280 : break;
1566 574 : case RTE_JOIN:
1567 : case RTE_CTE:
1568 : case RTE_NAMEDTUPLESTORE:
1569 : case RTE_RESULT:
1570 : case RTE_GROUP:
1571 : /* these can't contain any lateral references */
1572 574 : break;
1573 : }
1574 : }
1575 : }
1576 :
1577 : /*
1578 : * Now append the adjusted rtable entries and their perminfos to upper
1579 : * query. (We hold off until after fixing the upper rtable entries; no
1580 : * point in running that code on the subquery ones too.)
1581 : */
1582 37054 : CombineRangeTables(&parse->rtable, &parse->rteperminfos,
1583 : subquery->rtable, subquery->rteperminfos);
1584 :
1585 : /*
1586 : * Pull up any FOR UPDATE/SHARE markers, too. (OffsetVarNodes already
1587 : * adjusted the marker rtindexes, so just concat the lists.)
1588 : */
1589 37054 : parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
1590 :
1591 : /*
1592 : * We also have to fix the relid sets of any PlaceHolderVar nodes in the
1593 : * parent query. (This could perhaps be done by pullup_replace_vars(),
1594 : * but it seems cleaner to use two passes.) Note in particular that any
1595 : * PlaceHolderVar nodes just created by pullup_replace_vars() will be
1596 : * adjusted, so having created them with the subquery's varno is correct.
1597 : *
1598 : * Likewise, relids appearing in AppendRelInfo nodes have to be fixed. We
1599 : * already checked that this won't require introducing multiple subrelids
1600 : * into the single-slot AppendRelInfo structs.
1601 : */
1602 37054 : if (root->glob->lastPHId != 0 || root->append_rel_list)
1603 : {
1604 : Relids subrelids;
1605 :
1606 8160 : subrelids = get_relids_in_jointree((Node *) subquery->jointree,
1607 : true, false);
1608 8160 : if (root->glob->lastPHId != 0)
1609 1984 : substitute_phv_relids((Node *) parse, varno, subrelids);
1610 8160 : fix_append_rel_relids(root, varno, subrelids);
1611 : }
1612 :
1613 : /*
1614 : * And now add subquery's AppendRelInfos to our list.
1615 : */
1616 74108 : root->append_rel_list = list_concat(root->append_rel_list,
1617 37054 : subroot->append_rel_list);
1618 :
1619 : /*
1620 : * We don't have to do the equivalent bookkeeping for outer-join info,
1621 : * because that hasn't been set up yet. placeholder_list likewise.
1622 : */
1623 : Assert(root->join_info_list == NIL);
1624 : Assert(subroot->join_info_list == NIL);
1625 : Assert(root->placeholder_list == NIL);
1626 : Assert(subroot->placeholder_list == NIL);
1627 :
1628 : /*
1629 : * We no longer need the RTE's copy of the subquery's query tree. Getting
1630 : * rid of it saves nothing in particular so far as this level of query is
1631 : * concerned; but if this query level is in turn pulled up into a parent,
1632 : * we'd waste cycles copying the now-unused query tree.
1633 : */
1634 37054 : rte->subquery = NULL;
1635 :
1636 : /*
1637 : * Miscellaneous housekeeping.
1638 : *
1639 : * Although replace_rte_variables() faithfully updated parse->hasSubLinks
1640 : * if it copied any SubLinks out of the subquery's targetlist, we still
1641 : * could have SubLinks added to the query in the expressions of FUNCTION
1642 : * and VALUES RTEs copied up from the subquery. So it's necessary to copy
1643 : * subquery->hasSubLinks anyway. Perhaps this can be improved someday.
1644 : */
1645 37054 : parse->hasSubLinks |= subquery->hasSubLinks;
1646 :
1647 : /* If subquery had any RLS conditions, now main query does too */
1648 37054 : parse->hasRowSecurity |= subquery->hasRowSecurity;
1649 :
1650 : /*
1651 : * subquery won't be pulled up if it hasAggs, hasWindowFuncs, or
1652 : * hasTargetSRFs, so no work needed on those flags
1653 : */
1654 :
1655 : /*
1656 : * Return the adjusted subquery jointree to replace the RangeTblRef entry
1657 : * in parent's jointree; or, if the FromExpr is degenerate, just return
1658 : * its single member.
1659 : */
1660 : Assert(IsA(subquery->jointree, FromExpr));
1661 : Assert(subquery->jointree->fromlist != NIL);
1662 69006 : if (subquery->jointree->quals == NULL &&
1663 31952 : list_length(subquery->jointree->fromlist) == 1)
1664 31628 : return (Node *) linitial(subquery->jointree->fromlist);
1665 :
1666 5426 : return (Node *) subquery->jointree;
1667 : }
1668 :
1669 : /*
1670 : * pull_up_simple_union_all
1671 : * Pull up a single simple UNION ALL subquery.
1672 : *
1673 : * jtnode is a RangeTblRef that has been identified as a simple UNION ALL
1674 : * subquery by pull_up_subqueries. We pull up the leaf subqueries and
1675 : * build an "append relation" for the union set. The result value is just
1676 : * jtnode, since we don't actually need to change the query jointree.
1677 : */
1678 : static Node *
1679 4804 : pull_up_simple_union_all(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1680 : {
1681 4804 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1682 4804 : Query *subquery = rte->subquery;
1683 4804 : int rtoffset = list_length(root->parse->rtable);
1684 : List *rtable;
1685 :
1686 : /*
1687 : * Make a modifiable copy of the subquery's rtable, so we can adjust
1688 : * upper-level Vars in it. There are no such Vars in the setOperations
1689 : * tree proper, so fixing the rtable should be sufficient.
1690 : */
1691 4804 : rtable = copyObject(subquery->rtable);
1692 :
1693 : /*
1694 : * Upper-level vars in subquery are now one level closer to their parent
1695 : * than before. We don't have to worry about offsetting varnos, though,
1696 : * because the UNION leaf queries can't cross-reference each other.
1697 : */
1698 4804 : IncrementVarSublevelsUp_rtable(rtable, -1, 1);
1699 :
1700 : /*
1701 : * If the UNION ALL subquery had a LATERAL marker, propagate that to all
1702 : * its children. The individual children might or might not contain any
1703 : * actual lateral cross-references, but we have to mark the pulled-up
1704 : * child RTEs so that later planner stages will check for such.
1705 : */
1706 4804 : if (rte->lateral)
1707 : {
1708 : ListCell *rt;
1709 :
1710 198 : foreach(rt, rtable)
1711 : {
1712 132 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(rt);
1713 :
1714 : Assert(child_rte->rtekind == RTE_SUBQUERY);
1715 132 : child_rte->lateral = true;
1716 : }
1717 : }
1718 :
1719 : /*
1720 : * Append child RTEs (and their perminfos) to parent rtable.
1721 : */
1722 4804 : CombineRangeTables(&root->parse->rtable, &root->parse->rteperminfos,
1723 : rtable, subquery->rteperminfos);
1724 :
1725 : /*
1726 : * Recursively scan the subquery's setOperations tree and add
1727 : * AppendRelInfo nodes for leaf subqueries to the parent's
1728 : * append_rel_list. Also apply pull_up_subqueries to the leaf subqueries.
1729 : */
1730 : Assert(subquery->setOperations);
1731 4804 : pull_up_union_leaf_queries(subquery->setOperations, root, varno, subquery,
1732 : rtoffset);
1733 :
1734 : /*
1735 : * Mark the parent as an append relation.
1736 : */
1737 4804 : rte->inh = true;
1738 :
1739 4804 : return jtnode;
1740 : }
1741 :
1742 : /*
1743 : * pull_up_union_leaf_queries -- recursive guts of pull_up_simple_union_all
1744 : *
1745 : * Build an AppendRelInfo for each leaf query in the setop tree, and then
1746 : * apply pull_up_subqueries to the leaf query.
1747 : *
1748 : * Note that setOpQuery is the Query containing the setOp node, whose tlist
1749 : * contains references to all the setop output columns. When called from
1750 : * pull_up_simple_union_all, this is *not* the same as root->parse, which is
1751 : * the parent Query we are pulling up into.
1752 : *
1753 : * parentRTindex is the appendrel parent's index in root->parse->rtable.
1754 : *
1755 : * The child RTEs have already been copied to the parent. childRToffset
1756 : * tells us where in the parent's range table they were copied. When called
1757 : * from flatten_simple_union_all, childRToffset is 0 since the child RTEs
1758 : * were already in root->parse->rtable and no RT index adjustment is needed.
1759 : */
1760 : static void
1761 25802 : pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
1762 : Query *setOpQuery, int childRToffset)
1763 : {
1764 25802 : if (IsA(setOp, RangeTblRef))
1765 : {
1766 15538 : RangeTblRef *rtr = (RangeTblRef *) setOp;
1767 : int childRTindex;
1768 : AppendRelInfo *appinfo;
1769 :
1770 : /*
1771 : * Calculate the index in the parent's range table
1772 : */
1773 15538 : childRTindex = childRToffset + rtr->rtindex;
1774 :
1775 : /*
1776 : * Build a suitable AppendRelInfo, and attach to parent's list.
1777 : */
1778 15538 : appinfo = makeNode(AppendRelInfo);
1779 15538 : appinfo->parent_relid = parentRTindex;
1780 15538 : appinfo->child_relid = childRTindex;
1781 15538 : appinfo->parent_reltype = InvalidOid;
1782 15538 : appinfo->child_reltype = InvalidOid;
1783 15538 : make_setop_translation_list(setOpQuery, childRTindex, appinfo);
1784 15538 : appinfo->parent_reloid = InvalidOid;
1785 15538 : root->append_rel_list = lappend(root->append_rel_list, appinfo);
1786 :
1787 : /*
1788 : * Recursively apply pull_up_subqueries to the new child RTE. (We
1789 : * must build the AppendRelInfo first, because this will modify it;
1790 : * indeed, that's the only part of the upper query where Vars
1791 : * referencing childRTindex can exist at this point.)
1792 : *
1793 : * Note that we can pass NULL for containing-join info even if we're
1794 : * actually under an outer join, because the child's expressions
1795 : * aren't going to propagate up to the join. Also, we ignore the
1796 : * possibility that pull_up_subqueries_recurse() returns a different
1797 : * jointree node than what we pass it; if it does, the important thing
1798 : * is that it replaced the child relid in the AppendRelInfo node.
1799 : */
1800 15538 : rtr = makeNode(RangeTblRef);
1801 15538 : rtr->rtindex = childRTindex;
1802 15538 : (void) pull_up_subqueries_recurse(root, (Node *) rtr,
1803 : NULL, appinfo);
1804 : }
1805 10264 : else if (IsA(setOp, SetOperationStmt))
1806 : {
1807 10264 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1808 :
1809 : /* Recurse to reach leaf queries */
1810 10264 : pull_up_union_leaf_queries(op->larg, root, parentRTindex, setOpQuery,
1811 : childRToffset);
1812 10264 : pull_up_union_leaf_queries(op->rarg, root, parentRTindex, setOpQuery,
1813 : childRToffset);
1814 : }
1815 : else
1816 : {
1817 0 : elog(ERROR, "unrecognized node type: %d",
1818 : (int) nodeTag(setOp));
1819 : }
1820 25802 : }
1821 :
1822 : /*
1823 : * make_setop_translation_list
1824 : * Build the list of translations from parent Vars to child Vars for
1825 : * a UNION ALL member. (At this point it's just a simple list of
1826 : * referencing Vars, but if we succeed in pulling up the member
1827 : * subquery, the Vars will get replaced by pulled-up expressions.)
1828 : * Also create the rather trivial reverse-translation array.
1829 : */
1830 : static void
1831 15538 : make_setop_translation_list(Query *query, int newvarno,
1832 : AppendRelInfo *appinfo)
1833 : {
1834 15538 : List *vars = NIL;
1835 : AttrNumber *pcolnos;
1836 : ListCell *l;
1837 :
1838 : /* Initialize reverse-translation array with all entries zero */
1839 : /* (entries for resjunk columns will stay that way) */
1840 15538 : appinfo->num_child_cols = list_length(query->targetList);
1841 15538 : appinfo->parent_colnos = pcolnos =
1842 15538 : (AttrNumber *) palloc0(appinfo->num_child_cols * sizeof(AttrNumber));
1843 :
1844 70684 : foreach(l, query->targetList)
1845 : {
1846 55146 : TargetEntry *tle = (TargetEntry *) lfirst(l);
1847 :
1848 55146 : if (tle->resjunk)
1849 0 : continue;
1850 :
1851 55146 : vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
1852 55146 : pcolnos[tle->resno - 1] = tle->resno;
1853 : }
1854 :
1855 15538 : appinfo->translated_vars = vars;
1856 15538 : }
1857 :
1858 : /*
1859 : * is_simple_subquery
1860 : * Check a subquery in the range table to see if it's simple enough
1861 : * to pull up into the parent query.
1862 : *
1863 : * rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
1864 : * (Note subquery is not necessarily equal to rte->subquery; it could be a
1865 : * processed copy of that.)
1866 : * lowest_outer_join is the lowest outer join above the subquery, or NULL.
1867 : */
1868 : static bool
1869 96142 : is_simple_subquery(PlannerInfo *root, Query *subquery, RangeTblEntry *rte,
1870 : JoinExpr *lowest_outer_join)
1871 : {
1872 : /*
1873 : * Let's just make sure it's a valid subselect ...
1874 : */
1875 96142 : if (!IsA(subquery, Query) ||
1876 96142 : subquery->commandType != CMD_SELECT)
1877 0 : elog(ERROR, "subquery is bogus");
1878 :
1879 : /*
1880 : * Can't currently pull up a query with setops (unless it's simple UNION
1881 : * ALL, which is handled by a different code path). Maybe after querytree
1882 : * redesign...
1883 : */
1884 96142 : if (subquery->setOperations)
1885 5646 : return false;
1886 :
1887 : /*
1888 : * Can't pull up a subquery involving grouping, aggregation, SRFs,
1889 : * sorting, limiting, or WITH. (XXX WITH could possibly be allowed later)
1890 : *
1891 : * We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
1892 : * clauses, because pullup would cause the locking to occur semantically
1893 : * higher than it should. Implicit FOR UPDATE/SHARE is okay because in
1894 : * that case the locking was originally declared in the upper query
1895 : * anyway.
1896 : */
1897 90496 : if (subquery->hasAggs ||
1898 88820 : subquery->hasWindowFuncs ||
1899 88434 : subquery->hasTargetSRFs ||
1900 84242 : subquery->groupClause ||
1901 84162 : subquery->groupingSets ||
1902 84162 : subquery->havingQual ||
1903 84162 : subquery->sortClause ||
1904 83286 : subquery->distinctClause ||
1905 83016 : subquery->limitOffset ||
1906 82566 : subquery->limitCount ||
1907 82256 : subquery->hasForUpdate ||
1908 81652 : subquery->cteList)
1909 9012 : return false;
1910 :
1911 : /*
1912 : * Don't pull up if the RTE represents a security-barrier view; we
1913 : * couldn't prevent information leakage once the RTE's Vars are scattered
1914 : * about in the upper query.
1915 : */
1916 81484 : if (rte->security_barrier)
1917 692 : return false;
1918 :
1919 : /*
1920 : * If the subquery is LATERAL, check for pullup restrictions from that.
1921 : */
1922 80792 : if (rte->lateral)
1923 : {
1924 : bool restricted;
1925 : Relids safe_upper_varnos;
1926 :
1927 : /*
1928 : * The subquery's WHERE and JOIN/ON quals mustn't contain any lateral
1929 : * references to rels outside a higher outer join (including the case
1930 : * where the outer join is within the subquery itself). In such a
1931 : * case, pulling up would result in a situation where we need to
1932 : * postpone quals from below an outer join to above it, which is
1933 : * probably completely wrong and in any case is a complication that
1934 : * doesn't seem worth addressing at the moment.
1935 : */
1936 2404 : if (lowest_outer_join != NULL)
1937 : {
1938 1356 : restricted = true;
1939 1356 : safe_upper_varnos = get_relids_in_jointree((Node *) lowest_outer_join,
1940 : true, true);
1941 : }
1942 : else
1943 : {
1944 1048 : restricted = false;
1945 1048 : safe_upper_varnos = NULL; /* doesn't matter */
1946 : }
1947 :
1948 2404 : if (jointree_contains_lateral_outer_refs(root,
1949 2404 : (Node *) subquery->jointree,
1950 : restricted, safe_upper_varnos))
1951 24 : return false;
1952 :
1953 : /*
1954 : * If there's an outer join above the LATERAL subquery, also disallow
1955 : * pullup if the subquery's targetlist has any references to rels
1956 : * outside the outer join, since these might get pulled into quals
1957 : * above the subquery (but in or below the outer join) and then lead
1958 : * to qual-postponement issues similar to the case checked for above.
1959 : * (We wouldn't need to prevent pullup if no such references appear in
1960 : * outer-query quals, but we don't have enough info here to check
1961 : * that. Also, maybe this restriction could be removed if we forced
1962 : * such refs to be wrapped in PlaceHolderVars, even when they're below
1963 : * the nearest outer join? But it's a pretty hokey usage, so not
1964 : * clear this is worth sweating over.)
1965 : *
1966 : * If you change this, see also the comments about lateral references
1967 : * in pullup_replace_vars_callback().
1968 : */
1969 2380 : if (lowest_outer_join != NULL)
1970 : {
1971 1356 : Relids lvarnos = pull_varnos_of_level(root,
1972 1356 : (Node *) subquery->targetList,
1973 : 1);
1974 :
1975 1356 : if (!bms_is_subset(lvarnos, safe_upper_varnos))
1976 12 : return false;
1977 : }
1978 : }
1979 :
1980 : /*
1981 : * Don't pull up a subquery that has any volatile functions in its
1982 : * targetlist. Otherwise we might introduce multiple evaluations of these
1983 : * functions, if they get copied to multiple places in the upper query,
1984 : * leading to surprising results. (Note: the PlaceHolderVar mechanism
1985 : * doesn't quite guarantee single evaluation; else we could pull up anyway
1986 : * and just wrap such items in PlaceHolderVars ...)
1987 : */
1988 80756 : if (contain_volatile_functions((Node *) subquery->targetList))
1989 254 : return false;
1990 :
1991 80502 : return true;
1992 : }
1993 :
1994 : /*
1995 : * pull_up_simple_values
1996 : * Pull up a single simple VALUES RTE.
1997 : *
1998 : * jtnode is a RangeTblRef that has been identified as a simple VALUES RTE
1999 : * by pull_up_subqueries. We always return a RangeTblRef representing a
2000 : * RESULT RTE to replace it (all failure cases should have been detected by
2001 : * is_simple_values()). Actually, what we return is just jtnode, because
2002 : * we replace the VALUES RTE in the rangetable with the RESULT RTE.
2003 : *
2004 : * rte is the RangeTblEntry referenced by jtnode. Because of the limited
2005 : * possible usage of VALUES RTEs, we do not need the remaining parameters
2006 : * of pull_up_subqueries_recurse.
2007 : */
2008 : static Node *
2009 4504 : pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
2010 : {
2011 4504 : Query *parse = root->parse;
2012 4504 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2013 : List *values_list;
2014 : List *tlist;
2015 : AttrNumber attrno;
2016 : pullup_replace_vars_context rvcontext;
2017 : ListCell *lc;
2018 :
2019 : Assert(rte->rtekind == RTE_VALUES);
2020 : Assert(list_length(rte->values_lists) == 1);
2021 :
2022 : /*
2023 : * Need a modifiable copy of the VALUES list to hack on, just in case it's
2024 : * multiply referenced.
2025 : */
2026 4504 : values_list = copyObject(linitial(rte->values_lists));
2027 :
2028 : /*
2029 : * The VALUES RTE can't contain any Vars of level zero, let alone any that
2030 : * are join aliases, so no need to flatten join alias Vars.
2031 : */
2032 : Assert(!contain_vars_of_level((Node *) values_list, 0));
2033 :
2034 : /*
2035 : * Set up required context data for pullup_replace_vars. In particular,
2036 : * we have to make the VALUES list look like a subquery targetlist.
2037 : */
2038 4504 : tlist = NIL;
2039 4504 : attrno = 1;
2040 9724 : foreach(lc, values_list)
2041 : {
2042 5220 : tlist = lappend(tlist,
2043 5220 : makeTargetEntry((Expr *) lfirst(lc),
2044 : attrno,
2045 : NULL,
2046 : false));
2047 5220 : attrno++;
2048 : }
2049 4504 : rvcontext.root = root;
2050 4504 : rvcontext.targetlist = tlist;
2051 4504 : rvcontext.target_rte = rte;
2052 4504 : rvcontext.result_relation = 0;
2053 4504 : rvcontext.relids = NULL; /* can't be any lateral references here */
2054 4504 : rvcontext.nullinfo = NULL;
2055 4504 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2056 4504 : rvcontext.varno = varno;
2057 4504 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2058 : /* initialize cache array with indexes 0 .. length(tlist) */
2059 4504 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
2060 : sizeof(Node *));
2061 :
2062 : /*
2063 : * Replace all of the top query's references to the RTE's outputs with
2064 : * copies of the adjusted VALUES expressions, being careful not to replace
2065 : * any of the jointree structure. We can assume there's no outer joins or
2066 : * appendrels in the dummy Query that surrounds a VALUES RTE.
2067 : */
2068 4504 : perform_pullup_replace_vars(root, &rvcontext, NULL);
2069 :
2070 : /*
2071 : * There should be no appendrels to fix, nor any outer joins and hence no
2072 : * PlaceHolderVars.
2073 : */
2074 : Assert(root->append_rel_list == NIL);
2075 : Assert(root->join_info_list == NIL);
2076 : Assert(root->placeholder_list == NIL);
2077 :
2078 : /*
2079 : * Replace the VALUES RTE with a RESULT RTE. The VALUES RTE is the only
2080 : * rtable entry in the current query level, so this is easy.
2081 : */
2082 : Assert(list_length(parse->rtable) == 1);
2083 :
2084 : /* Create suitable RTE */
2085 4504 : rte = makeNode(RangeTblEntry);
2086 4504 : rte->rtekind = RTE_RESULT;
2087 4504 : rte->eref = makeAlias("*RESULT*", NIL);
2088 :
2089 : /* Replace rangetable */
2090 4504 : parse->rtable = list_make1(rte);
2091 :
2092 : /* We could manufacture a new RangeTblRef, but the one we have is fine */
2093 : Assert(varno == 1);
2094 :
2095 4504 : return jtnode;
2096 : }
2097 :
2098 : /*
2099 : * is_simple_values
2100 : * Check a VALUES RTE in the range table to see if it's simple enough
2101 : * to pull up into the parent query.
2102 : *
2103 : * rte is the RTE_VALUES RangeTblEntry to check.
2104 : */
2105 : static bool
2106 12774 : is_simple_values(PlannerInfo *root, RangeTblEntry *rte)
2107 : {
2108 : Assert(rte->rtekind == RTE_VALUES);
2109 :
2110 : /*
2111 : * There must be exactly one VALUES list, else it's not semantically
2112 : * correct to replace the VALUES RTE with a RESULT RTE, nor would we have
2113 : * a unique set of expressions to substitute into the parent query.
2114 : */
2115 12774 : if (list_length(rte->values_lists) != 1)
2116 8270 : return false;
2117 :
2118 : /*
2119 : * Because VALUES can't appear under an outer join (or at least, we won't
2120 : * try to pull it up if it does), we need not worry about LATERAL, nor
2121 : * about validity of PHVs for the VALUES' outputs.
2122 : */
2123 :
2124 : /*
2125 : * Don't pull up a VALUES that contains any set-returning or volatile
2126 : * functions. The considerations here are basically identical to the
2127 : * restrictions on a pull-able subquery's targetlist.
2128 : */
2129 9008 : if (expression_returns_set((Node *) rte->values_lists) ||
2130 4504 : contain_volatile_functions((Node *) rte->values_lists))
2131 0 : return false;
2132 :
2133 : /*
2134 : * Do not pull up a VALUES that's not the only RTE in its parent query.
2135 : * This is actually the only case that the parser will generate at the
2136 : * moment, and assuming this is true greatly simplifies
2137 : * pull_up_simple_values().
2138 : */
2139 4504 : if (list_length(root->parse->rtable) != 1 ||
2140 4504 : rte != (RangeTblEntry *) linitial(root->parse->rtable))
2141 0 : return false;
2142 :
2143 4504 : return true;
2144 : }
2145 :
2146 : /*
2147 : * pull_up_constant_function
2148 : * Pull up an RTE_FUNCTION expression that was simplified to a constant.
2149 : *
2150 : * jtnode is a RangeTblRef that has been identified as a FUNCTION RTE by
2151 : * pull_up_subqueries. If its expression is just a Const, hoist that value
2152 : * up into the parent query, and replace the RTE_FUNCTION with RTE_RESULT.
2153 : *
2154 : * In principle we could pull up any immutable expression, but we don't.
2155 : * That might result in multiple evaluations of the expression, which could
2156 : * be costly if it's not just a Const. Also, the main value of this is
2157 : * to let the constant participate in further const-folding, and of course
2158 : * that won't happen for a non-Const.
2159 : *
2160 : * The pulled-up value might need to be wrapped in a PlaceHolderVar if the
2161 : * RTE is below an outer join or is part of an appendrel; the extra
2162 : * parameters show whether that's needed.
2163 : */
2164 : static Node *
2165 51712 : pull_up_constant_function(PlannerInfo *root, Node *jtnode,
2166 : RangeTblEntry *rte,
2167 : AppendRelInfo *containing_appendrel)
2168 : {
2169 51712 : Query *parse = root->parse;
2170 : RangeTblFunction *rtf;
2171 : TypeFuncClass functypclass;
2172 : Oid funcrettype;
2173 : TupleDesc tupdesc;
2174 : pullup_replace_vars_context rvcontext;
2175 :
2176 : /* Fail if the RTE has ORDINALITY - we don't implement that here. */
2177 51712 : if (rte->funcordinality)
2178 922 : return jtnode;
2179 :
2180 : /* Fail if RTE isn't a single, simple Const expr */
2181 50790 : if (list_length(rte->functions) != 1)
2182 72 : return jtnode;
2183 50718 : rtf = linitial_node(RangeTblFunction, rte->functions);
2184 50718 : if (!IsA(rtf->funcexpr, Const))
2185 50346 : return jtnode;
2186 :
2187 : /*
2188 : * If the function's result is not a scalar, we punt. In principle we
2189 : * could break the composite constant value apart into per-column
2190 : * constants, but for now it seems not worth the work.
2191 : */
2192 372 : if (rtf->funccolcount != 1)
2193 30 : return jtnode; /* definitely composite */
2194 :
2195 : /* If it has a coldeflist, it certainly returns RECORD */
2196 342 : if (rtf->funccolnames != NIL)
2197 0 : return jtnode; /* must be a one-column RECORD type */
2198 :
2199 342 : functypclass = get_expr_result_type(rtf->funcexpr,
2200 : &funcrettype,
2201 : &tupdesc);
2202 342 : if (functypclass != TYPEFUNC_SCALAR)
2203 12 : return jtnode; /* must be a one-column composite type */
2204 :
2205 : /* Create context for applying pullup_replace_vars */
2206 330 : rvcontext.root = root;
2207 330 : rvcontext.targetlist = list_make1(makeTargetEntry((Expr *) rtf->funcexpr,
2208 : 1, /* resno */
2209 : NULL, /* resname */
2210 : false)); /* resjunk */
2211 330 : rvcontext.target_rte = rte;
2212 330 : rvcontext.result_relation = 0;
2213 :
2214 : /*
2215 : * Since this function was reduced to a Const, it doesn't contain any
2216 : * lateral references, even if it's marked as LATERAL. This means we
2217 : * don't need to fill relids or nullinfo.
2218 : */
2219 330 : rvcontext.relids = NULL;
2220 330 : rvcontext.nullinfo = NULL;
2221 :
2222 330 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2223 330 : rvcontext.varno = ((RangeTblRef *) jtnode)->rtindex;
2224 : /* this flag will be set below, if needed */
2225 330 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2226 : /* initialize cache array with indexes 0 .. length(tlist) */
2227 330 : rvcontext.rv_cache = palloc0((list_length(rvcontext.targetlist) + 1) *
2228 : sizeof(Node *));
2229 :
2230 : /*
2231 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
2232 : * each expression of the subquery's targetlist items. (See comments in
2233 : * pull_up_simple_subquery().)
2234 : */
2235 330 : if (parse->groupingSets)
2236 0 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
2237 :
2238 : /*
2239 : * Replace all of the top query's references to the RTE's output with
2240 : * copies of the funcexpr, being careful not to replace any of the
2241 : * jointree structure.
2242 : */
2243 330 : perform_pullup_replace_vars(root, &rvcontext,
2244 : containing_appendrel);
2245 :
2246 : /*
2247 : * We don't need to bother with changing PlaceHolderVars in the parent
2248 : * query. Their references to the RT index are still good for now, and
2249 : * will get removed later if we're able to drop the RTE_RESULT.
2250 : */
2251 :
2252 : /*
2253 : * Convert the RTE to be RTE_RESULT type, signifying that we don't need to
2254 : * scan it anymore, and zero out RTE_FUNCTION-specific fields. Also make
2255 : * sure the RTE is not marked LATERAL, since elsewhere we don't expect
2256 : * RTE_RESULTs to be LATERAL.
2257 : */
2258 330 : rte->rtekind = RTE_RESULT;
2259 330 : rte->functions = NIL;
2260 330 : rte->lateral = false;
2261 :
2262 : /*
2263 : * We can reuse the RangeTblRef node.
2264 : */
2265 330 : return jtnode;
2266 : }
2267 :
2268 : /*
2269 : * is_simple_union_all
2270 : * Check a subquery to see if it's a simple UNION ALL.
2271 : *
2272 : * We require all the setops to be UNION ALL (no mixing) and there can't be
2273 : * any datatype coercions involved, ie, all the leaf queries must emit the
2274 : * same datatypes.
2275 : */
2276 : static bool
2277 21566 : is_simple_union_all(Query *subquery)
2278 : {
2279 : SetOperationStmt *topop;
2280 :
2281 : /* Let's just make sure it's a valid subselect ... */
2282 21566 : if (!IsA(subquery, Query) ||
2283 21566 : subquery->commandType != CMD_SELECT)
2284 0 : elog(ERROR, "subquery is bogus");
2285 :
2286 : /* Is it a set-operation query at all? */
2287 21566 : topop = castNode(SetOperationStmt, subquery->setOperations);
2288 21566 : if (!topop)
2289 15920 : return false;
2290 :
2291 : /* Can't handle ORDER BY, LIMIT/OFFSET, locking, or WITH */
2292 5646 : if (subquery->sortClause ||
2293 5582 : subquery->limitOffset ||
2294 5582 : subquery->limitCount ||
2295 5582 : subquery->rowMarks ||
2296 5582 : subquery->cteList)
2297 252 : return false;
2298 :
2299 : /* Recursively check the tree of set operations */
2300 5394 : return is_simple_union_all_recurse((Node *) topop, subquery,
2301 : topop->colTypes);
2302 : }
2303 :
2304 : static bool
2305 33326 : is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes)
2306 : {
2307 : /* Since this function recurses, it could be driven to stack overflow. */
2308 33326 : check_stack_depth();
2309 :
2310 33326 : if (IsA(setOp, RangeTblRef))
2311 : {
2312 16830 : RangeTblRef *rtr = (RangeTblRef *) setOp;
2313 16830 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
2314 16830 : Query *subquery = rte->subquery;
2315 :
2316 : Assert(subquery != NULL);
2317 :
2318 : /* Leaf nodes are OK if they match the toplevel column types */
2319 : /* We don't have to compare typmods or collations here */
2320 16830 : return tlist_same_datatypes(subquery->targetList, colTypes, true);
2321 : }
2322 16496 : else if (IsA(setOp, SetOperationStmt))
2323 : {
2324 16496 : SetOperationStmt *op = (SetOperationStmt *) setOp;
2325 :
2326 : /* Must be UNION ALL */
2327 16496 : if (op->op != SETOP_UNION || !op->all)
2328 5012 : return false;
2329 :
2330 : /* Recurse to check inputs */
2331 22286 : return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
2332 10802 : is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
2333 : }
2334 : else
2335 : {
2336 0 : elog(ERROR, "unrecognized node type: %d",
2337 : (int) nodeTag(setOp));
2338 : return false; /* keep compiler quiet */
2339 : }
2340 : }
2341 :
2342 : /*
2343 : * is_safe_append_member
2344 : * Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
2345 : * safe to pull up.
2346 : */
2347 : static bool
2348 18830 : is_safe_append_member(Query *subquery)
2349 : {
2350 : FromExpr *jtnode;
2351 :
2352 : /*
2353 : * It's only safe to pull up the child if its jointree contains exactly
2354 : * one RTE, else the AppendRelInfo data structure breaks. The one base RTE
2355 : * could be buried in several levels of FromExpr, however. Also, if the
2356 : * child's jointree is completely empty, we can pull up because
2357 : * pull_up_simple_subquery will insert a single RTE_RESULT RTE instead.
2358 : *
2359 : * Also, the child can't have any WHERE quals because there's no place to
2360 : * put them in an appendrel. (This is a bit annoying...) If we didn't
2361 : * need to check this, we'd just test whether get_relids_in_jointree()
2362 : * yields a singleton set, to be more consistent with the coding of
2363 : * fix_append_rel_relids().
2364 : */
2365 18830 : jtnode = subquery->jointree;
2366 : Assert(IsA(jtnode, FromExpr));
2367 : /* Check the completely-empty case */
2368 18830 : if (jtnode->fromlist == NIL && jtnode->quals == NULL)
2369 584 : return true;
2370 : /* Check the more general case */
2371 32084 : while (IsA(jtnode, FromExpr))
2372 : {
2373 18258 : if (jtnode->quals != NULL)
2374 4420 : return false;
2375 13838 : if (list_length(jtnode->fromlist) != 1)
2376 0 : return false;
2377 13838 : jtnode = linitial(jtnode->fromlist);
2378 : }
2379 13826 : if (!IsA(jtnode, RangeTblRef))
2380 1734 : return false;
2381 :
2382 12092 : return true;
2383 : }
2384 :
2385 : /*
2386 : * jointree_contains_lateral_outer_refs
2387 : * Check for disallowed lateral references in a jointree's quals
2388 : *
2389 : * If restricted is false, all level-1 Vars are allowed (but we still must
2390 : * search the jointree, since it might contain outer joins below which there
2391 : * will be restrictions). If restricted is true, return true when any qual
2392 : * in the jointree contains level-1 Vars coming from outside the rels listed
2393 : * in safe_upper_varnos.
2394 : */
2395 : static bool
2396 5172 : jointree_contains_lateral_outer_refs(PlannerInfo *root, Node *jtnode,
2397 : bool restricted,
2398 : Relids safe_upper_varnos)
2399 : {
2400 5172 : if (jtnode == NULL)
2401 0 : return false;
2402 5172 : if (IsA(jtnode, RangeTblRef))
2403 2406 : return false;
2404 2766 : else if (IsA(jtnode, FromExpr))
2405 : {
2406 2452 : FromExpr *f = (FromExpr *) jtnode;
2407 : ListCell *l;
2408 :
2409 : /* First, recurse to check child joins */
2410 4568 : foreach(l, f->fromlist)
2411 : {
2412 2140 : if (jointree_contains_lateral_outer_refs(root,
2413 2140 : lfirst(l),
2414 : restricted,
2415 : safe_upper_varnos))
2416 24 : return true;
2417 : }
2418 :
2419 : /* Then check the top-level quals */
2420 2428 : if (restricted &&
2421 1404 : !bms_is_subset(pull_varnos_of_level(root, f->quals, 1),
2422 : safe_upper_varnos))
2423 0 : return true;
2424 : }
2425 314 : else if (IsA(jtnode, JoinExpr))
2426 : {
2427 314 : JoinExpr *j = (JoinExpr *) jtnode;
2428 :
2429 : /*
2430 : * If this is an outer join, we mustn't allow any upper lateral
2431 : * references in or below it.
2432 : */
2433 314 : if (j->jointype != JOIN_INNER)
2434 : {
2435 158 : restricted = true;
2436 158 : safe_upper_varnos = NULL;
2437 : }
2438 :
2439 : /* Check the child joins */
2440 314 : if (jointree_contains_lateral_outer_refs(root,
2441 : j->larg,
2442 : restricted,
2443 : safe_upper_varnos))
2444 0 : return true;
2445 314 : if (jointree_contains_lateral_outer_refs(root,
2446 : j->rarg,
2447 : restricted,
2448 : safe_upper_varnos))
2449 0 : return true;
2450 :
2451 : /* Check the JOIN's qual clauses */
2452 314 : if (restricted &&
2453 290 : !bms_is_subset(pull_varnos_of_level(root, j->quals, 1),
2454 : safe_upper_varnos))
2455 24 : return true;
2456 : }
2457 : else
2458 0 : elog(ERROR, "unrecognized node type: %d",
2459 : (int) nodeTag(jtnode));
2460 2718 : return false;
2461 : }
2462 :
2463 : /*
2464 : * Perform pullup_replace_vars everyplace it's needed in the query tree.
2465 : *
2466 : * Caller has already filled *rvcontext with data describing what to
2467 : * substitute for Vars referencing the target subquery. In addition
2468 : * we need the identity of the containing appendrel if any.
2469 : */
2470 : static void
2471 41894 : perform_pullup_replace_vars(PlannerInfo *root,
2472 : pullup_replace_vars_context *rvcontext,
2473 : AppendRelInfo *containing_appendrel)
2474 : {
2475 41894 : Query *parse = root->parse;
2476 : ListCell *lc;
2477 :
2478 : /*
2479 : * If we are considering an appendrel child subquery (that is, a UNION ALL
2480 : * member query that we're pulling up), then the only part of the upper
2481 : * query that could reference the child yet is the translated_vars list of
2482 : * the associated AppendRelInfo. Furthermore, we do not want to force use
2483 : * of PHVs in the AppendRelInfo --- there isn't any outer join between.
2484 : */
2485 41894 : if (containing_appendrel)
2486 : {
2487 6230 : ReplaceWrapOption save_wrap_option = rvcontext->wrap_option;
2488 :
2489 6230 : rvcontext->wrap_option = REPLACE_WRAP_NONE;
2490 6230 : containing_appendrel->translated_vars = (List *)
2491 6230 : pullup_replace_vars((Node *) containing_appendrel->translated_vars,
2492 : rvcontext);
2493 6230 : rvcontext->wrap_option = save_wrap_option;
2494 6230 : return;
2495 : }
2496 :
2497 : /*
2498 : * Replace all of the top query's references to the subquery's outputs
2499 : * with copies of the adjusted subtlist items, being careful not to
2500 : * replace any of the jointree structure. (This'd be a lot cleaner if we
2501 : * could use query_tree_mutator.) We have to use PHVs in the targetList,
2502 : * returningList, and havingQual, since those are certainly above any
2503 : * outer join. replace_vars_in_jointree tracks its location in the
2504 : * jointree and uses PHVs or not appropriately.
2505 : */
2506 35664 : parse->targetList = (List *)
2507 35664 : pullup_replace_vars((Node *) parse->targetList, rvcontext);
2508 35664 : parse->returningList = (List *)
2509 35664 : pullup_replace_vars((Node *) parse->returningList, rvcontext);
2510 :
2511 35664 : if (parse->onConflict)
2512 : {
2513 44 : parse->onConflict->onConflictSet = (List *)
2514 22 : pullup_replace_vars((Node *) parse->onConflict->onConflictSet,
2515 : rvcontext);
2516 22 : parse->onConflict->onConflictWhere =
2517 22 : pullup_replace_vars(parse->onConflict->onConflictWhere,
2518 : rvcontext);
2519 :
2520 : /*
2521 : * We assume ON CONFLICT's arbiterElems, arbiterWhere, exclRelTlist
2522 : * can't contain any references to a subquery.
2523 : */
2524 : }
2525 35664 : if (parse->mergeActionList)
2526 : {
2527 2996 : foreach(lc, parse->mergeActionList)
2528 : {
2529 1784 : MergeAction *action = lfirst(lc);
2530 :
2531 1784 : action->qual = pullup_replace_vars(action->qual, rvcontext);
2532 1784 : action->targetList = (List *)
2533 1784 : pullup_replace_vars((Node *) action->targetList, rvcontext);
2534 : }
2535 : }
2536 35664 : parse->mergeJoinCondition = pullup_replace_vars(parse->mergeJoinCondition,
2537 : rvcontext);
2538 35664 : replace_vars_in_jointree((Node *) parse->jointree, rvcontext);
2539 : Assert(parse->setOperations == NULL);
2540 35658 : parse->havingQual = pullup_replace_vars(parse->havingQual, rvcontext);
2541 :
2542 : /*
2543 : * Replace references in the translated_vars lists of appendrels.
2544 : */
2545 35694 : foreach(lc, root->append_rel_list)
2546 : {
2547 36 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(lc);
2548 :
2549 36 : appinfo->translated_vars = (List *)
2550 36 : pullup_replace_vars((Node *) appinfo->translated_vars, rvcontext);
2551 : }
2552 :
2553 : /*
2554 : * Replace references in the joinaliasvars lists of join RTEs and the
2555 : * groupexprs list of group RTE.
2556 : */
2557 99754 : foreach(lc, parse->rtable)
2558 : {
2559 64096 : RangeTblEntry *otherrte = (RangeTblEntry *) lfirst(lc);
2560 :
2561 64096 : if (otherrte->rtekind == RTE_JOIN)
2562 6772 : otherrte->joinaliasvars = (List *)
2563 6772 : pullup_replace_vars((Node *) otherrte->joinaliasvars,
2564 : rvcontext);
2565 57324 : else if (otherrte->rtekind == RTE_GROUP)
2566 736 : otherrte->groupexprs = (List *)
2567 736 : pullup_replace_vars((Node *) otherrte->groupexprs,
2568 : rvcontext);
2569 : }
2570 : }
2571 :
2572 : /*
2573 : * Helper routine for perform_pullup_replace_vars: do pullup_replace_vars on
2574 : * every expression in the jointree, without changing the jointree structure
2575 : * itself. Ugly, but there's no other way...
2576 : */
2577 : static void
2578 93124 : replace_vars_in_jointree(Node *jtnode,
2579 : pullup_replace_vars_context *context)
2580 : {
2581 93124 : if (jtnode == NULL)
2582 0 : return;
2583 93124 : if (IsA(jtnode, RangeTblRef))
2584 : {
2585 : /*
2586 : * If the RangeTblRef refers to a LATERAL subquery (that isn't the
2587 : * same subquery we're pulling up), it might contain references to the
2588 : * target subquery, which we must replace. We drive this from the
2589 : * jointree scan, rather than a scan of the rtable, so that we can
2590 : * avoid processing no-longer-referenced RTEs.
2591 : */
2592 46768 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2593 :
2594 46768 : if (varno != context->varno) /* ignore target subquery itself */
2595 : {
2596 11104 : RangeTblEntry *rte = rt_fetch(varno, context->root->parse->rtable);
2597 :
2598 : Assert(rte != context->target_rte);
2599 11104 : if (rte->lateral)
2600 : {
2601 908 : switch (rte->rtekind)
2602 : {
2603 0 : case RTE_RELATION:
2604 : /* shouldn't be marked LATERAL unless tablesample */
2605 : Assert(rte->tablesample);
2606 0 : rte->tablesample = (TableSampleClause *)
2607 0 : pullup_replace_vars((Node *) rte->tablesample,
2608 : context);
2609 0 : break;
2610 450 : case RTE_SUBQUERY:
2611 450 : rte->subquery =
2612 450 : pullup_replace_vars_subquery(rte->subquery,
2613 : context);
2614 450 : break;
2615 350 : case RTE_FUNCTION:
2616 350 : rte->functions = (List *)
2617 350 : pullup_replace_vars((Node *) rte->functions,
2618 : context);
2619 350 : break;
2620 108 : case RTE_TABLEFUNC:
2621 108 : rte->tablefunc = (TableFunc *)
2622 108 : pullup_replace_vars((Node *) rte->tablefunc,
2623 : context);
2624 108 : break;
2625 0 : case RTE_VALUES:
2626 0 : rte->values_lists = (List *)
2627 0 : pullup_replace_vars((Node *) rte->values_lists,
2628 : context);
2629 0 : break;
2630 0 : case RTE_JOIN:
2631 : case RTE_CTE:
2632 : case RTE_NAMEDTUPLESTORE:
2633 : case RTE_RESULT:
2634 : case RTE_GROUP:
2635 : /* these shouldn't be marked LATERAL */
2636 : Assert(false);
2637 0 : break;
2638 : }
2639 : }
2640 : }
2641 : }
2642 46356 : else if (IsA(jtnode, FromExpr))
2643 : {
2644 38368 : FromExpr *f = (FromExpr *) jtnode;
2645 : ListCell *l;
2646 :
2647 79852 : foreach(l, f->fromlist)
2648 41484 : replace_vars_in_jointree(lfirst(l), context);
2649 38368 : f->quals = pullup_replace_vars(f->quals, context);
2650 : }
2651 7988 : else if (IsA(jtnode, JoinExpr))
2652 : {
2653 7988 : JoinExpr *j = (JoinExpr *) jtnode;
2654 7988 : ReplaceWrapOption save_wrap_option = context->wrap_option;
2655 :
2656 7988 : replace_vars_in_jointree(j->larg, context);
2657 7988 : replace_vars_in_jointree(j->rarg, context);
2658 :
2659 : /*
2660 : * Use PHVs within the join quals of a full join for variable-free
2661 : * expressions. Otherwise, we cannot identify which side of the join
2662 : * a pulled-up variable-free expression came from, which can lead to
2663 : * failure to make a plan at all because none of the quals appear to
2664 : * be mergeable or hashable conditions.
2665 : */
2666 7988 : if (j->jointype == JOIN_FULL)
2667 622 : context->wrap_option = REPLACE_WRAP_VARFREE;
2668 :
2669 7988 : j->quals = pullup_replace_vars(j->quals, context);
2670 :
2671 7988 : context->wrap_option = save_wrap_option;
2672 : }
2673 : else
2674 0 : elog(ERROR, "unrecognized node type: %d",
2675 : (int) nodeTag(jtnode));
2676 : }
2677 :
2678 : /*
2679 : * Apply pullup variable replacement throughout an expression tree
2680 : *
2681 : * Returns a modified copy of the tree, so this can't be used where we
2682 : * need to do in-place replacement.
2683 : */
2684 : static Node *
2685 207916 : pullup_replace_vars(Node *expr, pullup_replace_vars_context *context)
2686 : {
2687 207916 : return replace_rte_variables(expr,
2688 : context->varno, 0,
2689 : pullup_replace_vars_callback,
2690 : context,
2691 : context->outer_hasSubLinks);
2692 : }
2693 :
2694 : static Node *
2695 115630 : pullup_replace_vars_callback(Var *var,
2696 : replace_rte_variables_context *context)
2697 : {
2698 115630 : pullup_replace_vars_context *rcon = (pullup_replace_vars_context *) context->callback_arg;
2699 115630 : int varattno = var->varattno;
2700 : bool need_phv;
2701 : Node *newnode;
2702 :
2703 : /* System columns are not replaced. */
2704 115630 : if (varattno < InvalidAttrNumber)
2705 42 : return (Node *) copyObject(var);
2706 :
2707 : /*
2708 : * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
2709 : * varnullingrels (unless we find below that the replacement expression is
2710 : * a Var or PlaceHolderVar that we can just add the nullingrels to). We
2711 : * also need one if the caller has instructed us that certain expression
2712 : * replacements need to be wrapped for identification purposes.
2713 : */
2714 219356 : need_phv = (var->varnullingrels != NULL) ||
2715 103768 : (rcon->wrap_option != REPLACE_WRAP_NONE);
2716 :
2717 : /*
2718 : * If PlaceHolderVars are needed, we cache the modified expressions in
2719 : * rcon->rv_cache[]. This is not in hopes of any material speed gain
2720 : * within this function, but to avoid generating identical PHVs with
2721 : * different IDs. That would result in duplicate evaluations at runtime,
2722 : * and possibly prevent optimizations that rely on recognizing different
2723 : * references to the same subquery output as being equal(). So it's worth
2724 : * a bit of extra effort to avoid it.
2725 : *
2726 : * The cached items have phlevelsup = 0 and phnullingrels = NULL; we'll
2727 : * copy them and adjust those values for this reference site below.
2728 : */
2729 115588 : if (need_phv &&
2730 13780 : varattno >= InvalidAttrNumber &&
2731 13780 : varattno <= list_length(rcon->targetlist) &&
2732 13780 : rcon->rv_cache[varattno] != NULL)
2733 : {
2734 : /* Just copy the entry and fall through to adjust phlevelsup etc */
2735 2810 : newnode = copyObject(rcon->rv_cache[varattno]);
2736 : }
2737 : else
2738 : {
2739 : /*
2740 : * Generate the replacement expression. This takes care of expanding
2741 : * wholerow references and dealing with non-default varreturningtype.
2742 : */
2743 112778 : newnode = ReplaceVarFromTargetList(var,
2744 : rcon->target_rte,
2745 : rcon->targetlist,
2746 : rcon->result_relation,
2747 : REPLACEVARS_REPORT_ERROR,
2748 : 0);
2749 :
2750 : /* Insert PlaceHolderVar if needed */
2751 112778 : if (need_phv)
2752 : {
2753 : bool wrap;
2754 :
2755 10970 : if (rcon->wrap_option == REPLACE_WRAP_ALL)
2756 : {
2757 : /* Caller told us to wrap all expressions in a PlaceHolderVar */
2758 800 : wrap = true;
2759 : }
2760 10170 : else if (varattno == InvalidAttrNumber)
2761 : {
2762 : /*
2763 : * Insert PlaceHolderVar for whole-tuple reference. Notice
2764 : * that we are wrapping one PlaceHolderVar around the whole
2765 : * RowExpr, rather than putting one around each element of the
2766 : * row. This is because we need the expression to yield NULL,
2767 : * not ROW(NULL,NULL,...) when it is forced to null by an
2768 : * outer join.
2769 : */
2770 66 : wrap = true;
2771 : }
2772 10104 : else if (newnode && IsA(newnode, Var) &&
2773 8090 : ((Var *) newnode)->varlevelsup == 0)
2774 : {
2775 : /*
2776 : * Simple Vars always escape being wrapped, unless they are
2777 : * lateral references to something outside the subquery being
2778 : * pulled up and the referenced rel is not under the same
2779 : * lowest nulling outer join.
2780 : */
2781 8074 : wrap = false;
2782 8074 : if (rcon->target_rte->lateral &&
2783 1410 : !bms_is_member(((Var *) newnode)->varno, rcon->relids))
2784 : {
2785 132 : nullingrel_info *nullinfo = rcon->nullinfo;
2786 132 : int lvarno = ((Var *) newnode)->varno;
2787 :
2788 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2789 132 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2790 132 : nullinfo->nullingrels[lvarno]))
2791 108 : wrap = true;
2792 : }
2793 : }
2794 2030 : else if (newnode && IsA(newnode, PlaceHolderVar) &&
2795 180 : ((PlaceHolderVar *) newnode)->phlevelsup == 0)
2796 : {
2797 : /* The same rules apply for a PlaceHolderVar */
2798 180 : wrap = false;
2799 180 : if (rcon->target_rte->lateral &&
2800 48 : !bms_is_subset(((PlaceHolderVar *) newnode)->phrels,
2801 48 : rcon->relids))
2802 : {
2803 48 : nullingrel_info *nullinfo = rcon->nullinfo;
2804 48 : Relids lvarnos = ((PlaceHolderVar *) newnode)->phrels;
2805 : int lvarno;
2806 :
2807 48 : lvarno = -1;
2808 72 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2809 : {
2810 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2811 48 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2812 48 : nullinfo->nullingrels[lvarno]))
2813 : {
2814 24 : wrap = true;
2815 24 : break;
2816 : }
2817 : }
2818 : }
2819 : }
2820 : else
2821 : {
2822 : /*
2823 : * If the node contains Var(s) or PlaceHolderVar(s) of the
2824 : * subquery being pulled up, or of rels that are under the
2825 : * same lowest nulling outer join as the subquery, and does
2826 : * not contain any non-strict constructs, then instead of
2827 : * adding a PHV on top we can add the required nullingrels to
2828 : * those Vars/PHVs. (This is fundamentally a generalization
2829 : * of the above cases for bare Vars and PHVs.)
2830 : *
2831 : * This test is somewhat expensive, but it avoids pessimizing
2832 : * the plan in cases where the nullingrels get removed again
2833 : * later by outer join reduction.
2834 : *
2835 : * Note that we don't force wrapping of expressions containing
2836 : * lateral references, so long as they also contain Vars/PHVs
2837 : * of the subquery, or of rels that are under the same lowest
2838 : * nulling outer join as the subquery. This is okay because
2839 : * of the restriction to strict constructs: if those Vars/PHVs
2840 : * have been forced to NULL by an outer join then the end
2841 : * result of the expression will be NULL too, regardless of
2842 : * the lateral references. So it's not necessary to force the
2843 : * expression to be evaluated below the outer join. This can
2844 : * be a very valuable optimization, because it may allow us to
2845 : * avoid using a nested loop to pass the lateral reference
2846 : * down.
2847 : *
2848 : * This analysis could be tighter: in particular, a non-strict
2849 : * construct hidden within a lower-level PlaceHolderVar is not
2850 : * reason to add another PHV. But for now it doesn't seem
2851 : * worth the code to be more exact. This is also why it's
2852 : * preferable to handle bare PHVs in the above branch, rather
2853 : * than this branch. We also prefer to handle bare Vars in a
2854 : * separate branch, as it's cheaper this way and parallels the
2855 : * handling of PHVs.
2856 : *
2857 : * For a LATERAL subquery, we have to check the actual var
2858 : * membership of the node, but if it's non-lateral then any
2859 : * level-zero var must belong to the subquery.
2860 : */
2861 1850 : bool contain_nullable_vars = false;
2862 :
2863 1850 : if (!rcon->target_rte->lateral)
2864 : {
2865 1622 : if (contain_vars_of_level(newnode, 0))
2866 534 : contain_nullable_vars = true;
2867 : }
2868 : else
2869 : {
2870 : Relids all_varnos;
2871 :
2872 228 : all_varnos = pull_varnos(rcon->root, newnode);
2873 228 : if (bms_overlap(all_varnos, rcon->relids))
2874 132 : contain_nullable_vars = true;
2875 : else
2876 : {
2877 96 : nullingrel_info *nullinfo = rcon->nullinfo;
2878 : int varno;
2879 :
2880 96 : varno = -1;
2881 180 : while ((varno = bms_next_member(all_varnos, varno)) >= 0)
2882 : {
2883 : Assert(varno > 0 && varno <= nullinfo->rtlength);
2884 108 : if (bms_is_subset(nullinfo->nullingrels[rcon->varno],
2885 108 : nullinfo->nullingrels[varno]))
2886 : {
2887 24 : contain_nullable_vars = true;
2888 24 : break;
2889 : }
2890 : }
2891 : }
2892 : }
2893 :
2894 1850 : if (contain_nullable_vars &&
2895 690 : !contain_nonstrict_functions(newnode))
2896 : {
2897 : /* No wrap needed */
2898 288 : wrap = false;
2899 : }
2900 : else
2901 : {
2902 : /* Else wrap it in a PlaceHolderVar */
2903 1562 : wrap = true;
2904 : }
2905 : }
2906 :
2907 10970 : if (wrap)
2908 : {
2909 : newnode = (Node *)
2910 2560 : make_placeholder_expr(rcon->root,
2911 : (Expr *) newnode,
2912 : bms_make_singleton(rcon->varno));
2913 :
2914 : /*
2915 : * Cache it if possible (ie, if the attno is in range, which
2916 : * it probably always should be).
2917 : */
2918 5120 : if (varattno >= InvalidAttrNumber &&
2919 2560 : varattno <= list_length(rcon->targetlist))
2920 2560 : rcon->rv_cache[varattno] = copyObject(newnode);
2921 : }
2922 : }
2923 : }
2924 :
2925 : /* Propagate any varnullingrels into the replacement expression */
2926 115588 : if (var->varnullingrels != NULL)
2927 : {
2928 11820 : if (IsA(newnode, Var))
2929 : {
2930 7476 : Var *newvar = (Var *) newnode;
2931 :
2932 : Assert(newvar->varlevelsup == 0);
2933 7476 : newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
2934 7476 : var->varnullingrels);
2935 : }
2936 4344 : else if (IsA(newnode, PlaceHolderVar))
2937 : {
2938 4056 : PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
2939 :
2940 : Assert(newphv->phlevelsup == 0);
2941 4056 : newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
2942 4056 : var->varnullingrels);
2943 : }
2944 : else
2945 : {
2946 : /*
2947 : * There should be Vars/PHVs within the expression that we can
2948 : * modify. Vars/PHVs of the subquery should have the full
2949 : * var->varnullingrels added to them, but if there are lateral
2950 : * references within the expression, those must be marked with
2951 : * only the nullingrels that potentially apply to them. (This
2952 : * corresponds to the fact that the expression will now be
2953 : * evaluated at the join level of the Var that we are replacing:
2954 : * the lateral references may have bubbled up through fewer outer
2955 : * joins than the subquery's Vars have. Per the discussion above,
2956 : * we'll still get the right answers.) That relid set could be
2957 : * different for different lateral relations, so we have to do
2958 : * this work for each one.
2959 : *
2960 : * (Currently, the restrictions in is_simple_subquery() mean that
2961 : * at most we have to remove the lowest outer join's relid from
2962 : * the nullingrels of a lateral reference. However, we might
2963 : * relax those restrictions someday, so let's do this right.)
2964 : */
2965 288 : if (rcon->target_rte->lateral)
2966 : {
2967 84 : nullingrel_info *nullinfo = rcon->nullinfo;
2968 : Relids lvarnos;
2969 : int lvarno;
2970 :
2971 : /*
2972 : * Identify lateral varnos used within newnode. We must do
2973 : * this before injecting var->varnullingrels into the tree.
2974 : */
2975 84 : lvarnos = pull_varnos(rcon->root, newnode);
2976 84 : lvarnos = bms_del_members(lvarnos, rcon->relids);
2977 : /* For each one, add relevant nullingrels if any */
2978 84 : lvarno = -1;
2979 168 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2980 : {
2981 : Relids lnullingrels;
2982 :
2983 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2984 84 : lnullingrels = bms_intersect(var->varnullingrels,
2985 84 : nullinfo->nullingrels[lvarno]);
2986 84 : if (!bms_is_empty(lnullingrels))
2987 48 : newnode = add_nulling_relids(newnode,
2988 48 : bms_make_singleton(lvarno),
2989 : lnullingrels);
2990 : }
2991 : }
2992 :
2993 : /* Finally, deal with Vars/PHVs of the subquery itself */
2994 288 : newnode = add_nulling_relids(newnode,
2995 288 : rcon->relids,
2996 288 : var->varnullingrels);
2997 : /* Assert we did put the varnullingrels into the expression */
2998 : Assert(bms_is_subset(var->varnullingrels,
2999 : pull_varnos(rcon->root, newnode)));
3000 : }
3001 : }
3002 :
3003 : /* Must adjust varlevelsup if replaced Var is within a subquery */
3004 115588 : if (var->varlevelsup > 0)
3005 1212 : IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
3006 :
3007 115588 : return newnode;
3008 : }
3009 :
3010 : /*
3011 : * Apply pullup variable replacement to a subquery
3012 : *
3013 : * This needs to be different from pullup_replace_vars() because
3014 : * replace_rte_variables will think that it shouldn't increment sublevels_up
3015 : * before entering the Query; so we need to call it with sublevels_up == 1.
3016 : */
3017 : static Query *
3018 450 : pullup_replace_vars_subquery(Query *query,
3019 : pullup_replace_vars_context *context)
3020 : {
3021 : Assert(IsA(query, Query));
3022 450 : return (Query *) replace_rte_variables((Node *) query,
3023 : context->varno, 1,
3024 : pullup_replace_vars_callback,
3025 : context,
3026 : NULL);
3027 : }
3028 :
3029 :
3030 : /*
3031 : * flatten_simple_union_all
3032 : * Try to optimize top-level UNION ALL structure into an appendrel
3033 : *
3034 : * If a query's setOperations tree consists entirely of simple UNION ALL
3035 : * operations, flatten it into an append relation, which we can process more
3036 : * intelligently than the general setops case. Otherwise, do nothing.
3037 : *
3038 : * In most cases, this can succeed only for a top-level query, because for a
3039 : * subquery in FROM, the parent query's invocation of pull_up_subqueries would
3040 : * already have flattened the UNION via pull_up_simple_union_all. But there
3041 : * are a few cases we can support here but not in that code path, for example
3042 : * when the subquery also contains ORDER BY.
3043 : */
3044 : void
3045 6580 : flatten_simple_union_all(PlannerInfo *root)
3046 : {
3047 6580 : Query *parse = root->parse;
3048 : SetOperationStmt *topop;
3049 : Node *leftmostjtnode;
3050 : int leftmostRTI;
3051 : RangeTblEntry *leftmostRTE;
3052 : int childRTI;
3053 : RangeTblEntry *childRTE;
3054 : RangeTblRef *rtr;
3055 :
3056 : /* Shouldn't be called unless query has setops */
3057 6580 : topop = castNode(SetOperationStmt, parse->setOperations);
3058 : Assert(topop);
3059 :
3060 : /* Can't optimize away a recursive UNION */
3061 6580 : if (root->hasRecursion)
3062 6110 : return;
3063 :
3064 : /*
3065 : * Recursively check the tree of set operations. If not all UNION ALL
3066 : * with identical column types, punt.
3067 : */
3068 5646 : if (!is_simple_union_all_recurse((Node *) topop, parse, topop->colTypes))
3069 5176 : return;
3070 :
3071 : /*
3072 : * Locate the leftmost leaf query in the setops tree. The upper query's
3073 : * Vars all refer to this RTE (see transformSetOperationStmt).
3074 : */
3075 470 : leftmostjtnode = topop->larg;
3076 870 : while (leftmostjtnode && IsA(leftmostjtnode, SetOperationStmt))
3077 400 : leftmostjtnode = ((SetOperationStmt *) leftmostjtnode)->larg;
3078 : Assert(leftmostjtnode && IsA(leftmostjtnode, RangeTblRef));
3079 470 : leftmostRTI = ((RangeTblRef *) leftmostjtnode)->rtindex;
3080 470 : leftmostRTE = rt_fetch(leftmostRTI, parse->rtable);
3081 : Assert(leftmostRTE->rtekind == RTE_SUBQUERY);
3082 :
3083 : /*
3084 : * Make a copy of the leftmost RTE and add it to the rtable. This copy
3085 : * will represent the leftmost leaf query in its capacity as a member of
3086 : * the appendrel. The original will represent the appendrel as a whole.
3087 : * (We must do things this way because the upper query's Vars have to be
3088 : * seen as referring to the whole appendrel.)
3089 : */
3090 470 : childRTE = copyObject(leftmostRTE);
3091 470 : parse->rtable = lappend(parse->rtable, childRTE);
3092 470 : childRTI = list_length(parse->rtable);
3093 :
3094 : /* Modify the setops tree to reference the child copy */
3095 470 : ((RangeTblRef *) leftmostjtnode)->rtindex = childRTI;
3096 :
3097 : /* Modify the formerly-leftmost RTE to mark it as an appendrel parent */
3098 470 : leftmostRTE->inh = true;
3099 :
3100 : /*
3101 : * Form a RangeTblRef for the appendrel, and insert it into FROM. The top
3102 : * Query of a setops tree should have had an empty FromClause initially.
3103 : */
3104 470 : rtr = makeNode(RangeTblRef);
3105 470 : rtr->rtindex = leftmostRTI;
3106 : Assert(parse->jointree->fromlist == NIL);
3107 470 : parse->jointree->fromlist = list_make1(rtr);
3108 :
3109 : /*
3110 : * Now pretend the query has no setops. We must do this before trying to
3111 : * do subquery pullup, because of Assert in pull_up_simple_subquery.
3112 : */
3113 470 : parse->setOperations = NULL;
3114 :
3115 : /*
3116 : * Build AppendRelInfo information, and apply pull_up_subqueries to the
3117 : * leaf queries of the UNION ALL. (We must do that now because they
3118 : * weren't previously referenced by the jointree, and so were missed by
3119 : * the main invocation of pull_up_subqueries.)
3120 : */
3121 470 : pull_up_union_leaf_queries((Node *) topop, root, leftmostRTI, parse, 0);
3122 : }
3123 :
3124 :
3125 : /*
3126 : * reduce_outer_joins
3127 : * Attempt to reduce outer joins to plain inner joins.
3128 : *
3129 : * The idea here is that given a query like
3130 : * SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
3131 : * we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
3132 : * is strict. The strict operator will always return NULL, causing the outer
3133 : * WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
3134 : * columns. Therefore, there's no need for the join to produce null-extended
3135 : * rows in the first place --- which makes it a plain join not an outer join.
3136 : * (This scenario may not be very likely in a query written out by hand, but
3137 : * it's reasonably likely when pushing quals down into complex views.)
3138 : *
3139 : * More generally, an outer join can be reduced in strength if there is a
3140 : * strict qual above it in the qual tree that constrains a Var from the
3141 : * nullable side of the join to be non-null. (For FULL joins this applies
3142 : * to each side separately.)
3143 : *
3144 : * Another transformation we apply here is to recognize cases like
3145 : * SELECT ... FROM a LEFT JOIN b ON (a.x = b.y) WHERE b.y IS NULL;
3146 : * If the join clause is strict for b.y, then only null-extended rows could
3147 : * pass the upper WHERE, and we can conclude that what the query is really
3148 : * specifying is an anti-semijoin. We change the join type from JOIN_LEFT
3149 : * to JOIN_ANTI. The IS NULL clause then becomes redundant, and must be
3150 : * removed to prevent bogus selectivity calculations, but we leave it to
3151 : * distribute_qual_to_rels to get rid of such clauses.
3152 : *
3153 : * Also, we get rid of JOIN_RIGHT cases by flipping them around to become
3154 : * JOIN_LEFT. This saves some code here and in some later planner routines;
3155 : * the main benefit is to reduce the number of jointypes that can appear in
3156 : * SpecialJoinInfo nodes. Note that we can still generate Paths and Plans
3157 : * that use JOIN_RIGHT (or JOIN_RIGHT_ANTI) by switching the inputs again.
3158 : *
3159 : * To ease recognition of strict qual clauses, we require this routine to be
3160 : * run after expression preprocessing (i.e., qual canonicalization and JOIN
3161 : * alias-var expansion).
3162 : */
3163 : void
3164 33808 : reduce_outer_joins(PlannerInfo *root)
3165 : {
3166 : reduce_outer_joins_pass1_state *state1;
3167 : reduce_outer_joins_pass2_state state2;
3168 : ListCell *lc;
3169 :
3170 : /*
3171 : * To avoid doing strictness checks on more quals than necessary, we want
3172 : * to stop descending the jointree as soon as there are no outer joins
3173 : * below our current point. This consideration forces a two-pass process.
3174 : * The first pass gathers information about which base rels appear below
3175 : * each side of each join clause, and about whether there are outer
3176 : * join(s) below each side of each join clause. The second pass examines
3177 : * qual clauses and changes join types as it descends the tree.
3178 : */
3179 33808 : state1 = reduce_outer_joins_pass1((Node *) root->parse->jointree);
3180 :
3181 : /* planner.c shouldn't have called me if no outer joins */
3182 33808 : if (state1 == NULL || !state1->contains_outer)
3183 0 : elog(ERROR, "so where are the outer joins?");
3184 :
3185 33808 : state2.inner_reduced = NULL;
3186 33808 : state2.partial_reduced = NIL;
3187 :
3188 33808 : reduce_outer_joins_pass2((Node *) root->parse->jointree,
3189 : state1, &state2,
3190 : root, NULL, NIL);
3191 :
3192 : /*
3193 : * If we successfully reduced the strength of any outer joins, we must
3194 : * remove references to those joins as nulling rels. This is handled as
3195 : * an additional pass, for simplicity and because we can handle all
3196 : * fully-reduced joins in a single pass over the parse tree.
3197 : */
3198 33808 : if (!bms_is_empty(state2.inner_reduced))
3199 : {
3200 1882 : root->parse = (Query *)
3201 1882 : remove_nulling_relids((Node *) root->parse,
3202 1882 : state2.inner_reduced,
3203 : NULL);
3204 : /* There could be references in the append_rel_list, too */
3205 1882 : root->append_rel_list = (List *)
3206 1882 : remove_nulling_relids((Node *) root->append_rel_list,
3207 1882 : state2.inner_reduced,
3208 : NULL);
3209 : }
3210 :
3211 : /*
3212 : * Partially-reduced full joins have to be done one at a time, since
3213 : * they'll each need a different setting of except_relids.
3214 : */
3215 33858 : foreach(lc, state2.partial_reduced)
3216 : {
3217 50 : reduce_outer_joins_partial_state *statep = lfirst(lc);
3218 50 : Relids full_join_relids = bms_make_singleton(statep->full_join_rti);
3219 :
3220 50 : root->parse = (Query *)
3221 50 : remove_nulling_relids((Node *) root->parse,
3222 : full_join_relids,
3223 50 : statep->unreduced_side);
3224 50 : root->append_rel_list = (List *)
3225 50 : remove_nulling_relids((Node *) root->append_rel_list,
3226 : full_join_relids,
3227 50 : statep->unreduced_side);
3228 : }
3229 33808 : }
3230 :
3231 : /*
3232 : * reduce_outer_joins_pass1 - phase 1 data collection
3233 : *
3234 : * Returns a state node describing the given jointree node.
3235 : */
3236 : static reduce_outer_joins_pass1_state *
3237 192490 : reduce_outer_joins_pass1(Node *jtnode)
3238 : {
3239 : reduce_outer_joins_pass1_state *result;
3240 :
3241 : result = (reduce_outer_joins_pass1_state *)
3242 192490 : palloc(sizeof(reduce_outer_joins_pass1_state));
3243 192490 : result->relids = NULL;
3244 192490 : result->contains_outer = false;
3245 192490 : result->sub_states = NIL;
3246 :
3247 192490 : if (jtnode == NULL)
3248 0 : return result;
3249 192490 : if (IsA(jtnode, RangeTblRef))
3250 : {
3251 96024 : int varno = ((RangeTblRef *) jtnode)->rtindex;
3252 :
3253 96024 : result->relids = bms_make_singleton(varno);
3254 : }
3255 96466 : else if (IsA(jtnode, FromExpr))
3256 : {
3257 37076 : FromExpr *f = (FromExpr *) jtnode;
3258 : ListCell *l;
3259 :
3260 76978 : foreach(l, f->fromlist)
3261 : {
3262 : reduce_outer_joins_pass1_state *sub_state;
3263 :
3264 39902 : sub_state = reduce_outer_joins_pass1(lfirst(l));
3265 79804 : result->relids = bms_add_members(result->relids,
3266 39902 : sub_state->relids);
3267 39902 : result->contains_outer |= sub_state->contains_outer;
3268 39902 : result->sub_states = lappend(result->sub_states, sub_state);
3269 : }
3270 : }
3271 59390 : else if (IsA(jtnode, JoinExpr))
3272 : {
3273 59390 : JoinExpr *j = (JoinExpr *) jtnode;
3274 : reduce_outer_joins_pass1_state *sub_state;
3275 :
3276 : /* join's own RT index is not wanted in result->relids */
3277 59390 : if (IS_OUTER_JOIN(j->jointype))
3278 48614 : result->contains_outer = true;
3279 :
3280 59390 : sub_state = reduce_outer_joins_pass1(j->larg);
3281 118780 : result->relids = bms_add_members(result->relids,
3282 59390 : sub_state->relids);
3283 59390 : result->contains_outer |= sub_state->contains_outer;
3284 59390 : result->sub_states = lappend(result->sub_states, sub_state);
3285 :
3286 59390 : sub_state = reduce_outer_joins_pass1(j->rarg);
3287 118780 : result->relids = bms_add_members(result->relids,
3288 59390 : sub_state->relids);
3289 59390 : result->contains_outer |= sub_state->contains_outer;
3290 59390 : result->sub_states = lappend(result->sub_states, sub_state);
3291 : }
3292 : else
3293 0 : elog(ERROR, "unrecognized node type: %d",
3294 : (int) nodeTag(jtnode));
3295 192490 : return result;
3296 : }
3297 :
3298 : /*
3299 : * reduce_outer_joins_pass2 - phase 2 processing
3300 : *
3301 : * jtnode: current jointree node
3302 : * state1: state data collected by phase 1 for this node
3303 : * state2: where to accumulate info about successfully-reduced joins
3304 : * root: toplevel planner state
3305 : * nonnullable_rels: set of base relids forced non-null by upper quals
3306 : * forced_null_vars: multibitmapset of Vars forced null by upper quals
3307 : *
3308 : * Returns info in state2 about outer joins that were successfully simplified.
3309 : * Joins that were fully reduced to inner joins are all added to
3310 : * state2->inner_reduced. If a full join is reduced to a left join,
3311 : * it needs its own entry in state2->partial_reduced, since that will
3312 : * require custom processing to remove only the correct nullingrel markers.
3313 : */
3314 : static void
3315 84476 : reduce_outer_joins_pass2(Node *jtnode,
3316 : reduce_outer_joins_pass1_state *state1,
3317 : reduce_outer_joins_pass2_state *state2,
3318 : PlannerInfo *root,
3319 : Relids nonnullable_rels,
3320 : List *forced_null_vars)
3321 : {
3322 : /*
3323 : * pass 2 should never descend as far as an empty subnode or base rel,
3324 : * because it's only called on subtrees marked as contains_outer.
3325 : */
3326 84476 : if (jtnode == NULL)
3327 0 : elog(ERROR, "reached empty jointree");
3328 84476 : if (IsA(jtnode, RangeTblRef))
3329 0 : elog(ERROR, "reached base rel");
3330 84476 : else if (IsA(jtnode, FromExpr))
3331 : {
3332 35244 : FromExpr *f = (FromExpr *) jtnode;
3333 : ListCell *l;
3334 : ListCell *s;
3335 : Relids pass_nonnullable_rels;
3336 : List *pass_forced_null_vars;
3337 :
3338 : /* Scan quals to see if we can add any constraints */
3339 35244 : pass_nonnullable_rels = find_nonnullable_rels(f->quals);
3340 35244 : pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels,
3341 : nonnullable_rels);
3342 35244 : pass_forced_null_vars = find_forced_null_vars(f->quals);
3343 35244 : pass_forced_null_vars = mbms_add_members(pass_forced_null_vars,
3344 : forced_null_vars);
3345 : /* And recurse --- but only into interesting subtrees */
3346 : Assert(list_length(f->fromlist) == list_length(state1->sub_states));
3347 73152 : forboth(l, f->fromlist, s, state1->sub_states)
3348 : {
3349 37908 : reduce_outer_joins_pass1_state *sub_state = lfirst(s);
3350 :
3351 37908 : if (sub_state->contains_outer)
3352 35274 : reduce_outer_joins_pass2(lfirst(l), sub_state,
3353 : state2, root,
3354 : pass_nonnullable_rels,
3355 : pass_forced_null_vars);
3356 : }
3357 35244 : bms_free(pass_nonnullable_rels);
3358 : /* can't so easily clean up var lists, unfortunately */
3359 : }
3360 49232 : else if (IsA(jtnode, JoinExpr))
3361 : {
3362 49232 : JoinExpr *j = (JoinExpr *) jtnode;
3363 49232 : int rtindex = j->rtindex;
3364 49232 : JoinType jointype = j->jointype;
3365 49232 : reduce_outer_joins_pass1_state *left_state = linitial(state1->sub_states);
3366 49232 : reduce_outer_joins_pass1_state *right_state = lsecond(state1->sub_states);
3367 :
3368 : /* Can we simplify this join? */
3369 49232 : switch (jointype)
3370 : {
3371 556 : case JOIN_INNER:
3372 556 : break;
3373 45908 : case JOIN_LEFT:
3374 45908 : if (bms_overlap(nonnullable_rels, right_state->relids))
3375 1940 : jointype = JOIN_INNER;
3376 45908 : break;
3377 1190 : case JOIN_RIGHT:
3378 1190 : if (bms_overlap(nonnullable_rels, left_state->relids))
3379 80 : jointype = JOIN_INNER;
3380 1190 : break;
3381 1090 : case JOIN_FULL:
3382 1090 : if (bms_overlap(nonnullable_rels, left_state->relids))
3383 : {
3384 24 : if (bms_overlap(nonnullable_rels, right_state->relids))
3385 12 : jointype = JOIN_INNER;
3386 : else
3387 : {
3388 12 : jointype = JOIN_LEFT;
3389 : /* Also report partial reduction in state2 */
3390 12 : report_reduced_full_join(state2, rtindex,
3391 : right_state->relids);
3392 : }
3393 : }
3394 : else
3395 : {
3396 1066 : if (bms_overlap(nonnullable_rels, right_state->relids))
3397 : {
3398 38 : jointype = JOIN_RIGHT;
3399 : /* Also report partial reduction in state2 */
3400 38 : report_reduced_full_join(state2, rtindex,
3401 : left_state->relids);
3402 : }
3403 : }
3404 1090 : break;
3405 488 : case JOIN_SEMI:
3406 : case JOIN_ANTI:
3407 :
3408 : /*
3409 : * These could only have been introduced by pull_up_sublinks,
3410 : * so there's no way that upper quals could refer to their
3411 : * righthand sides, and no point in checking. We don't expect
3412 : * to see JOIN_RIGHT_SEMI or JOIN_RIGHT_ANTI yet.
3413 : */
3414 488 : break;
3415 0 : default:
3416 0 : elog(ERROR, "unrecognized join type: %d",
3417 : (int) jointype);
3418 : break;
3419 : }
3420 :
3421 : /*
3422 : * Convert JOIN_RIGHT to JOIN_LEFT. Note that in the case where we
3423 : * reduced JOIN_FULL to JOIN_RIGHT, this will mean the JoinExpr no
3424 : * longer matches the internal ordering of any CoalesceExpr's built to
3425 : * represent merged join variables. We don't care about that at
3426 : * present, but be wary of it ...
3427 : */
3428 49232 : if (jointype == JOIN_RIGHT)
3429 : {
3430 : Node *tmparg;
3431 :
3432 1148 : tmparg = j->larg;
3433 1148 : j->larg = j->rarg;
3434 1148 : j->rarg = tmparg;
3435 1148 : jointype = JOIN_LEFT;
3436 1148 : right_state = linitial(state1->sub_states);
3437 1148 : left_state = lsecond(state1->sub_states);
3438 : }
3439 :
3440 : /*
3441 : * See if we can reduce JOIN_LEFT to JOIN_ANTI. This is the case if
3442 : * the join's own quals are strict for any var that was forced null by
3443 : * higher qual levels. NOTE: there are other ways that we could
3444 : * detect an anti-join, in particular if we were to check whether Vars
3445 : * coming from the RHS must be non-null because of table constraints.
3446 : * That seems complicated and expensive though (in particular, one
3447 : * would have to be wary of lower outer joins). For the moment this
3448 : * seems sufficient.
3449 : */
3450 49232 : if (jointype == JOIN_LEFT)
3451 : {
3452 : List *nonnullable_vars;
3453 : Bitmapset *overlap;
3454 :
3455 : /* Find Vars in j->quals that must be non-null in joined rows */
3456 45128 : nonnullable_vars = find_nonnullable_vars(j->quals);
3457 :
3458 : /*
3459 : * It's not sufficient to check whether nonnullable_vars and
3460 : * forced_null_vars overlap: we need to know if the overlap
3461 : * includes any RHS variables.
3462 : */
3463 45128 : overlap = mbms_overlap_sets(nonnullable_vars, forced_null_vars);
3464 45128 : if (bms_overlap(overlap, right_state->relids))
3465 1154 : jointype = JOIN_ANTI;
3466 : }
3467 :
3468 : /*
3469 : * Apply the jointype change, if any, to both jointree node and RTE.
3470 : * Also, if we changed an RTE to INNER, add its RTI to inner_reduced.
3471 : */
3472 49232 : if (rtindex && jointype != j->jointype)
3473 : {
3474 4346 : RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
3475 :
3476 : Assert(rte->rtekind == RTE_JOIN);
3477 : Assert(rte->jointype == j->jointype);
3478 4346 : rte->jointype = jointype;
3479 4346 : if (jointype == JOIN_INNER)
3480 2032 : state2->inner_reduced = bms_add_member(state2->inner_reduced,
3481 : rtindex);
3482 : }
3483 49232 : j->jointype = jointype;
3484 :
3485 : /* Only recurse if there's more to do below here */
3486 49232 : if (left_state->contains_outer || right_state->contains_outer)
3487 : {
3488 : Relids local_nonnullable_rels;
3489 : List *local_forced_null_vars;
3490 : Relids pass_nonnullable_rels;
3491 : List *pass_forced_null_vars;
3492 :
3493 : /*
3494 : * If this join is (now) inner, we can add any constraints its
3495 : * quals provide to those we got from above. But if it is outer,
3496 : * we can pass down the local constraints only into the nullable
3497 : * side, because an outer join never eliminates any rows from its
3498 : * non-nullable side. Also, there is no point in passing upper
3499 : * constraints into the nullable side, since if there were any
3500 : * we'd have been able to reduce the join. (In the case of upper
3501 : * forced-null constraints, we *must not* pass them into the
3502 : * nullable side --- they either applied here, or not.) The upshot
3503 : * is that we pass either the local or the upper constraints,
3504 : * never both, to the children of an outer join.
3505 : *
3506 : * Note that a SEMI join works like an inner join here: it's okay
3507 : * to pass down both local and upper constraints. (There can't be
3508 : * any upper constraints affecting its inner side, but it's not
3509 : * worth having a separate code path to avoid passing them.)
3510 : *
3511 : * At a FULL join we just punt and pass nothing down --- is it
3512 : * possible to be smarter?
3513 : */
3514 15326 : if (jointype != JOIN_FULL)
3515 : {
3516 15190 : local_nonnullable_rels = find_nonnullable_rels(j->quals);
3517 15190 : local_forced_null_vars = find_forced_null_vars(j->quals);
3518 15190 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3519 : {
3520 : /* OK to merge upper and local constraints */
3521 1010 : local_nonnullable_rels = bms_add_members(local_nonnullable_rels,
3522 : nonnullable_rels);
3523 1010 : local_forced_null_vars = mbms_add_members(local_forced_null_vars,
3524 : forced_null_vars);
3525 : }
3526 : }
3527 : else
3528 : {
3529 : /* no use in calculating these */
3530 136 : local_nonnullable_rels = NULL;
3531 136 : local_forced_null_vars = NIL;
3532 : }
3533 :
3534 15326 : if (left_state->contains_outer)
3535 : {
3536 14584 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3537 : {
3538 : /* pass union of local and upper constraints */
3539 798 : pass_nonnullable_rels = local_nonnullable_rels;
3540 798 : pass_forced_null_vars = local_forced_null_vars;
3541 : }
3542 13786 : else if (jointype != JOIN_FULL) /* ie, LEFT or ANTI */
3543 : {
3544 : /* can't pass local constraints to non-nullable side */
3545 13678 : pass_nonnullable_rels = nonnullable_rels;
3546 13678 : pass_forced_null_vars = forced_null_vars;
3547 : }
3548 : else
3549 : {
3550 : /* no constraints pass through JOIN_FULL */
3551 108 : pass_nonnullable_rels = NULL;
3552 108 : pass_forced_null_vars = NIL;
3553 : }
3554 14584 : reduce_outer_joins_pass2(j->larg, left_state,
3555 : state2, root,
3556 : pass_nonnullable_rels,
3557 : pass_forced_null_vars);
3558 : }
3559 :
3560 15326 : if (right_state->contains_outer)
3561 : {
3562 810 : if (jointype != JOIN_FULL) /* ie, INNER/LEFT/SEMI/ANTI */
3563 : {
3564 : /* pass appropriate constraints, per comment above */
3565 782 : pass_nonnullable_rels = local_nonnullable_rels;
3566 782 : pass_forced_null_vars = local_forced_null_vars;
3567 : }
3568 : else
3569 : {
3570 : /* no constraints pass through JOIN_FULL */
3571 28 : pass_nonnullable_rels = NULL;
3572 28 : pass_forced_null_vars = NIL;
3573 : }
3574 810 : reduce_outer_joins_pass2(j->rarg, right_state,
3575 : state2, root,
3576 : pass_nonnullable_rels,
3577 : pass_forced_null_vars);
3578 : }
3579 15326 : bms_free(local_nonnullable_rels);
3580 : }
3581 : }
3582 : else
3583 0 : elog(ERROR, "unrecognized node type: %d",
3584 : (int) nodeTag(jtnode));
3585 84476 : }
3586 :
3587 : /* Helper for reduce_outer_joins_pass2 */
3588 : static void
3589 50 : report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
3590 : int rtindex, Relids relids)
3591 : {
3592 : reduce_outer_joins_partial_state *statep;
3593 :
3594 50 : statep = palloc(sizeof(reduce_outer_joins_partial_state));
3595 50 : statep->full_join_rti = rtindex;
3596 50 : statep->unreduced_side = relids;
3597 50 : state2->partial_reduced = lappend(state2->partial_reduced, statep);
3598 50 : }
3599 :
3600 :
3601 : /*
3602 : * remove_useless_result_rtes
3603 : * Attempt to remove RTE_RESULT RTEs from the join tree.
3604 : * Also, elide single-child FromExprs where possible.
3605 : *
3606 : * We can remove RTE_RESULT entries from the join tree using the knowledge
3607 : * that RTE_RESULT returns exactly one row and has no output columns. Hence,
3608 : * if one is inner-joined to anything else, we can delete it. Optimizations
3609 : * are also possible for some outer-join cases, as detailed below.
3610 : *
3611 : * This pass also replaces single-child FromExprs with their child node
3612 : * where possible. It's appropriate to do that here and not earlier because
3613 : * RTE_RESULT removal might reduce a multiple-child FromExpr to have only one
3614 : * child. We can remove such a FromExpr if its quals are empty, or if it's
3615 : * semantically valid to merge the quals into those of the parent node.
3616 : * While removing unnecessary join tree nodes has some micro-efficiency value,
3617 : * the real reason to do this is to eliminate cases where the nullable side of
3618 : * an outer join node is a FromExpr whose single child is another outer join.
3619 : * To correctly determine whether the two outer joins can commute,
3620 : * deconstruct_jointree() must treat any quals of such a FromExpr as being
3621 : * degenerate quals of the upper outer join. The best way to do that is to
3622 : * make them actually *be* quals of the upper join, by dropping the FromExpr
3623 : * and hoisting the quals up into the upper join's quals. (Note that there is
3624 : * no hazard when the intermediate FromExpr has multiple children, since then
3625 : * it represents an inner join that cannot commute with the upper outer join.)
3626 : * As long as we have to do that, we might as well elide such FromExprs
3627 : * everywhere.
3628 : *
3629 : * Some of these optimizations depend on recognizing empty (constant-true)
3630 : * quals for FromExprs and JoinExprs. That makes it useful to apply this
3631 : * optimization pass after expression preprocessing, since that will have
3632 : * eliminated constant-true quals, allowing more cases to be recognized as
3633 : * optimizable. What's more, the usual reason for an RTE_RESULT to be present
3634 : * is that we pulled up a subquery or VALUES clause, thus very possibly
3635 : * replacing Vars with constants, making it more likely that a qual can be
3636 : * reduced to constant true. Also, because some optimizations depend on
3637 : * the outer-join type, it's best to have done reduce_outer_joins() first.
3638 : *
3639 : * A PlaceHolderVar referencing an RTE_RESULT RTE poses an obstacle to this
3640 : * process: we must remove the RTE_RESULT's relid from the PHV's phrels, but
3641 : * we must not reduce the phrels set to empty. If that would happen, and
3642 : * the RTE_RESULT is an immediate child of an outer join, we have to give up
3643 : * and not remove the RTE_RESULT: there is noplace else to evaluate the
3644 : * PlaceHolderVar. (That is, in such cases the RTE_RESULT *does* have output
3645 : * columns.) But if the RTE_RESULT is an immediate child of an inner join,
3646 : * we can usually change the PlaceHolderVar's phrels so as to evaluate it at
3647 : * the inner join instead. This is OK because we really only care that PHVs
3648 : * are evaluated above or below the correct outer joins. We can't, however,
3649 : * postpone the evaluation of a PHV to above where it is used; so there are
3650 : * some checks below on whether output PHVs are laterally referenced in the
3651 : * other join input rel(s).
3652 : *
3653 : * We used to try to do this work as part of pull_up_subqueries() where the
3654 : * potentially-optimizable cases get introduced; but it's way simpler, and
3655 : * more effective, to do it separately.
3656 : */
3657 : void
3658 234292 : remove_useless_result_rtes(PlannerInfo *root)
3659 : {
3660 234292 : Relids dropped_outer_joins = NULL;
3661 : ListCell *cell;
3662 :
3663 : /* Top level of jointree must always be a FromExpr */
3664 : Assert(IsA(root->parse->jointree, FromExpr));
3665 : /* Recurse ... */
3666 468584 : root->parse->jointree = (FromExpr *)
3667 234292 : remove_useless_results_recurse(root,
3668 234292 : (Node *) root->parse->jointree,
3669 : NULL,
3670 : &dropped_outer_joins);
3671 : /* We should still have a FromExpr */
3672 : Assert(IsA(root->parse->jointree, FromExpr));
3673 :
3674 : /*
3675 : * If we removed any outer-join nodes from the jointree, run around and
3676 : * remove references to those joins as nulling rels. (There could be such
3677 : * references in PHVs that we pulled up out of the original subquery that
3678 : * the RESULT rel replaced. This is kosher on the grounds that we now
3679 : * know that such an outer join wouldn't really have nulled anything.) We
3680 : * don't do this during the main recursion, for simplicity and because we
3681 : * can handle all such joins in a single pass over the parse tree.
3682 : */
3683 234292 : if (!bms_is_empty(dropped_outer_joins))
3684 : {
3685 60 : root->parse = (Query *)
3686 60 : remove_nulling_relids((Node *) root->parse,
3687 : dropped_outer_joins,
3688 : NULL);
3689 : /* There could be references in the append_rel_list, too */
3690 60 : root->append_rel_list = (List *)
3691 60 : remove_nulling_relids((Node *) root->append_rel_list,
3692 : dropped_outer_joins,
3693 : NULL);
3694 : }
3695 :
3696 : /*
3697 : * Remove any PlanRowMark referencing an RTE_RESULT RTE. We obviously
3698 : * must do that for any RTE_RESULT that we just removed. But one for a
3699 : * RTE that we did not remove can be dropped anyway: since the RTE has
3700 : * only one possible output row, there is no need for EPQ to mark and
3701 : * restore that row.
3702 : *
3703 : * It's necessary, not optional, to remove the PlanRowMark for a surviving
3704 : * RTE_RESULT RTE; otherwise we'll generate a whole-row Var for the
3705 : * RTE_RESULT, which the executor has no support for.
3706 : */
3707 236246 : foreach(cell, root->rowMarks)
3708 : {
3709 1954 : PlanRowMark *rc = (PlanRowMark *) lfirst(cell);
3710 :
3711 1954 : if (rt_fetch(rc->rti, root->parse->rtable)->rtekind == RTE_RESULT)
3712 828 : root->rowMarks = foreach_delete_current(root->rowMarks, cell);
3713 : }
3714 234292 : }
3715 :
3716 : /*
3717 : * remove_useless_results_recurse
3718 : * Recursive guts of remove_useless_result_rtes.
3719 : *
3720 : * This recursively processes the jointree and returns a modified jointree.
3721 : * In addition, the RT indexes of any removed outer-join nodes are added to
3722 : * *dropped_outer_joins.
3723 : *
3724 : * jtnode is the current jointree node. If it could be valid to merge
3725 : * its quals into those of the parent node, parent_quals should point to
3726 : * the parent's quals list; otherwise, pass NULL for parent_quals.
3727 : * (Note that in some cases, parent_quals points to the quals of a parent
3728 : * more than one level up in the tree.)
3729 : */
3730 : static Node *
3731 604958 : remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
3732 : Node **parent_quals,
3733 : Relids *dropped_outer_joins)
3734 : {
3735 : Assert(jtnode != NULL);
3736 604958 : if (IsA(jtnode, RangeTblRef))
3737 : {
3738 : /* Can't immediately do anything with a RangeTblRef */
3739 : }
3740 304148 : else if (IsA(jtnode, FromExpr))
3741 : {
3742 241102 : FromExpr *f = (FromExpr *) jtnode;
3743 241102 : Relids result_relids = NULL;
3744 : ListCell *cell;
3745 :
3746 : /*
3747 : * We can drop RTE_RESULT rels from the fromlist so long as at least
3748 : * one child remains, since joining to a one-row table changes
3749 : * nothing. (But we can't drop a RTE_RESULT that computes PHV(s) that
3750 : * are needed by some sibling. The cleanup transformation below would
3751 : * reassign the PHVs to be computed at the join, which is too late for
3752 : * the sibling's use.) The easiest way to mechanize this rule is to
3753 : * modify the list in-place.
3754 : */
3755 485676 : foreach(cell, f->fromlist)
3756 : {
3757 244574 : Node *child = (Node *) lfirst(cell);
3758 : int varno;
3759 :
3760 : /* Recursively transform child, allowing it to push up quals ... */
3761 244574 : child = remove_useless_results_recurse(root, child,
3762 : &f->quals,
3763 : dropped_outer_joins);
3764 : /* ... and stick it back into the tree */
3765 244574 : lfirst(cell) = child;
3766 :
3767 : /*
3768 : * If it's an RTE_RESULT with at least one sibling, and no sibling
3769 : * references dependent PHVs, we can drop it. We don't yet know
3770 : * what the inner join's final relid set will be, so postpone
3771 : * cleanup of PHVs etc till after this loop.
3772 : */
3773 250176 : if (list_length(f->fromlist) > 1 &&
3774 5602 : (varno = get_result_relid(root, child)) != 0 &&
3775 346 : !find_dependent_phvs_in_jointree(root, (Node *) f, varno))
3776 : {
3777 322 : f->fromlist = foreach_delete_current(f->fromlist, cell);
3778 322 : result_relids = bms_add_member(result_relids, varno);
3779 : }
3780 : }
3781 :
3782 : /*
3783 : * Clean up if we dropped any RTE_RESULT RTEs. This is a bit
3784 : * inefficient if there's more than one, but it seems better to
3785 : * optimize the support code for the single-relid case.
3786 : */
3787 241102 : if (result_relids)
3788 : {
3789 310 : int varno = -1;
3790 :
3791 632 : while ((varno = bms_next_member(result_relids, varno)) >= 0)
3792 322 : remove_result_refs(root, varno, (Node *) f);
3793 : }
3794 :
3795 : /*
3796 : * If the FromExpr now has only one child, see if we can elide it.
3797 : * This is always valid if there are no quals, except at the top of
3798 : * the jointree (since Query.jointree is required to point to a
3799 : * FromExpr). Otherwise, we can do it if we can push the quals up to
3800 : * the parent node.
3801 : *
3802 : * Note: while it would not be terribly hard to generalize this
3803 : * transformation to merge multi-child FromExprs into their parent
3804 : * FromExpr, that risks making the parent join too expensive to plan.
3805 : * We leave it to later processing to decide heuristically whether
3806 : * that's a good idea. Pulling up a single child is always OK,
3807 : * however.
3808 : */
3809 241102 : if (list_length(f->fromlist) == 1 &&
3810 239180 : f != root->parse->jointree &&
3811 6580 : (f->quals == NULL || parent_quals != NULL))
3812 : {
3813 : /*
3814 : * Merge any quals up to parent. They should be in implicit-AND
3815 : * format by now, so we just need to concatenate lists. Put the
3816 : * child quals at the front, on the grounds that they should
3817 : * nominally be evaluated earlier.
3818 : */
3819 2746 : if (f->quals != NULL)
3820 1398 : *parent_quals = (Node *)
3821 1398 : list_concat(castNode(List, f->quals),
3822 : castNode(List, *parent_quals));
3823 2746 : return (Node *) linitial(f->fromlist);
3824 : }
3825 : }
3826 63046 : else if (IsA(jtnode, JoinExpr))
3827 : {
3828 63046 : JoinExpr *j = (JoinExpr *) jtnode;
3829 : int varno;
3830 :
3831 : /*
3832 : * First, recurse. We can absorb pushed-up FromExpr quals from either
3833 : * child into this node if the jointype is INNER, since then this is
3834 : * equivalent to a FromExpr. When the jointype is LEFT, we can absorb
3835 : * quals from the RHS child into the current node, as they're
3836 : * essentially degenerate quals of the outer join. Moreover, if we've
3837 : * been passed down a parent_quals pointer then we can allow quals of
3838 : * the LHS child to be absorbed into the parent. (This is important
3839 : * to ensure we remove single-child FromExprs immediately below
3840 : * commutable left joins.) For other jointypes, we can't move child
3841 : * quals up, or at least there's no particular reason to.
3842 : */
3843 63046 : j->larg = remove_useless_results_recurse(root, j->larg,
3844 63046 : (j->jointype == JOIN_INNER) ?
3845 : &j->quals :
3846 49778 : (j->jointype == JOIN_LEFT) ?
3847 49778 : parent_quals : NULL,
3848 : dropped_outer_joins);
3849 63046 : j->rarg = remove_useless_results_recurse(root, j->rarg,
3850 63046 : (j->jointype == JOIN_INNER ||
3851 49778 : j->jointype == JOIN_LEFT) ?
3852 : &j->quals : NULL,
3853 : dropped_outer_joins);
3854 :
3855 : /* Apply join-type-specific optimization rules */
3856 63046 : switch (j->jointype)
3857 : {
3858 13268 : case JOIN_INNER:
3859 :
3860 : /*
3861 : * An inner join is equivalent to a FromExpr, so if either
3862 : * side was simplified to an RTE_RESULT rel, we can replace
3863 : * the join with a FromExpr with just the other side.
3864 : * Furthermore, we can elide that FromExpr according to the
3865 : * same rules as above.
3866 : *
3867 : * Just as in the FromExpr case, we can't simplify if the
3868 : * other input rel references any PHVs that are marked as to
3869 : * be evaluated at the RTE_RESULT rel, because we can't
3870 : * postpone their evaluation in that case. But we only have
3871 : * to check this in cases where it's syntactically legal for
3872 : * the other input to have a LATERAL reference to the
3873 : * RTE_RESULT rel. Only RHSes of inner and left joins are
3874 : * allowed to have such refs.
3875 : */
3876 13268 : if ((varno = get_result_relid(root, j->larg)) != 0 &&
3877 96 : !find_dependent_phvs_in_jointree(root, j->rarg, varno))
3878 : {
3879 96 : remove_result_refs(root, varno, j->rarg);
3880 96 : if (j->quals != NULL && parent_quals == NULL)
3881 12 : jtnode = (Node *)
3882 12 : makeFromExpr(list_make1(j->rarg), j->quals);
3883 : else
3884 : {
3885 : /* Merge any quals up to parent */
3886 84 : if (j->quals != NULL)
3887 60 : *parent_quals = (Node *)
3888 60 : list_concat(castNode(List, j->quals),
3889 : castNode(List, *parent_quals));
3890 84 : jtnode = j->rarg;
3891 : }
3892 : }
3893 13172 : else if ((varno = get_result_relid(root, j->rarg)) != 0)
3894 : {
3895 784 : remove_result_refs(root, varno, j->larg);
3896 784 : if (j->quals != NULL && parent_quals == NULL)
3897 12 : jtnode = (Node *)
3898 12 : makeFromExpr(list_make1(j->larg), j->quals);
3899 : else
3900 : {
3901 : /* Merge any quals up to parent */
3902 772 : if (j->quals != NULL)
3903 512 : *parent_quals = (Node *)
3904 512 : list_concat(castNode(List, j->quals),
3905 : castNode(List, *parent_quals));
3906 772 : jtnode = j->larg;
3907 : }
3908 : }
3909 13268 : break;
3910 43974 : case JOIN_LEFT:
3911 :
3912 : /*
3913 : * We can simplify this case if the RHS is an RTE_RESULT, with
3914 : * two different possibilities:
3915 : *
3916 : * If the qual is empty (JOIN ON TRUE), then the join can be
3917 : * strength-reduced to a plain inner join, since each LHS row
3918 : * necessarily has exactly one join partner. So we can always
3919 : * discard the RHS, much as in the JOIN_INNER case above.
3920 : * (Again, the LHS could not contain a lateral reference to
3921 : * the RHS.)
3922 : *
3923 : * Otherwise, it's still true that each LHS row should be
3924 : * returned exactly once, and since the RHS returns no columns
3925 : * (unless there are PHVs that have to be evaluated there), we
3926 : * don't much care if it's null-extended or not. So in this
3927 : * case also, we can just ignore the qual and discard the left
3928 : * join.
3929 : */
3930 43974 : if ((varno = get_result_relid(root, j->rarg)) != 0 &&
3931 150 : (j->quals == NULL ||
3932 90 : !find_dependent_phvs(root, varno)))
3933 : {
3934 60 : remove_result_refs(root, varno, j->larg);
3935 60 : *dropped_outer_joins = bms_add_member(*dropped_outer_joins,
3936 : j->rtindex);
3937 60 : jtnode = j->larg;
3938 : }
3939 43974 : break;
3940 3196 : case JOIN_SEMI:
3941 :
3942 : /*
3943 : * We may simplify this case if the RHS is an RTE_RESULT; the
3944 : * join qual becomes effectively just a filter qual for the
3945 : * LHS, since we should either return the LHS row or not. The
3946 : * filter clause must go into a new FromExpr if we can't push
3947 : * it up to the parent.
3948 : *
3949 : * There is a fine point about PHVs that are supposed to be
3950 : * evaluated at the RHS. Such PHVs could only appear in the
3951 : * semijoin's qual, since the rest of the query cannot
3952 : * reference any outputs of the semijoin's RHS. Therefore,
3953 : * they can't actually go to null before being examined, and
3954 : * it'd be OK to just remove the PHV wrapping. We don't have
3955 : * infrastructure for that, but remove_result_refs() will
3956 : * relabel them as to be evaluated at the LHS, which is fine.
3957 : *
3958 : * Also, we don't need to worry about removing traces of the
3959 : * join's rtindex, since it hasn't got one.
3960 : */
3961 3196 : if ((varno = get_result_relid(root, j->rarg)) != 0)
3962 : {
3963 : Assert(j->rtindex == 0);
3964 36 : remove_result_refs(root, varno, j->larg);
3965 36 : if (j->quals != NULL && parent_quals == NULL)
3966 0 : jtnode = (Node *)
3967 0 : makeFromExpr(list_make1(j->larg), j->quals);
3968 : else
3969 : {
3970 : /* Merge any quals up to parent */
3971 36 : if (j->quals != NULL)
3972 36 : *parent_quals = (Node *)
3973 36 : list_concat(castNode(List, j->quals),
3974 : castNode(List, *parent_quals));
3975 36 : jtnode = j->larg;
3976 : }
3977 : }
3978 3196 : break;
3979 2608 : case JOIN_FULL:
3980 : case JOIN_ANTI:
3981 : /* We have no special smarts for these cases */
3982 2608 : break;
3983 0 : default:
3984 : /* Note: JOIN_RIGHT should be gone at this point */
3985 0 : elog(ERROR, "unrecognized join type: %d",
3986 : (int) j->jointype);
3987 : break;
3988 : }
3989 : }
3990 : else
3991 0 : elog(ERROR, "unrecognized node type: %d",
3992 : (int) nodeTag(jtnode));
3993 602212 : return jtnode;
3994 : }
3995 :
3996 : /*
3997 : * get_result_relid
3998 : * If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
3999 : * otherwise return 0.
4000 : */
4001 : static int
4002 79212 : get_result_relid(PlannerInfo *root, Node *jtnode)
4003 : {
4004 : int varno;
4005 :
4006 79212 : if (!IsA(jtnode, RangeTblRef))
4007 6612 : return 0;
4008 72600 : varno = ((RangeTblRef *) jtnode)->rtindex;
4009 72600 : if (rt_fetch(varno, root->parse->rtable)->rtekind != RTE_RESULT)
4010 71188 : return 0;
4011 1412 : return varno;
4012 : }
4013 :
4014 : /*
4015 : * remove_result_refs
4016 : * Helper routine for dropping an unneeded RTE_RESULT RTE.
4017 : *
4018 : * This doesn't physically remove the RTE from the jointree, because that's
4019 : * more easily handled in remove_useless_results_recurse. What it does do
4020 : * is the necessary cleanup in the rest of the tree: we must adjust any PHVs
4021 : * that may reference the RTE. Be sure to call this at a point where the
4022 : * jointree is valid (no disconnected nodes).
4023 : *
4024 : * Note that we don't need to process the append_rel_list, since RTEs
4025 : * referenced directly in the jointree won't be appendrel members.
4026 : *
4027 : * varno is the RTE_RESULT's relid.
4028 : * newjtloc is the jointree location at which any PHVs referencing the
4029 : * RTE_RESULT should be evaluated instead.
4030 : */
4031 : static void
4032 1298 : remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc)
4033 : {
4034 : /* Fix up PlaceHolderVars as needed */
4035 : /* If there are no PHVs anywhere, we can skip this bit */
4036 1298 : if (root->glob->lastPHId != 0)
4037 : {
4038 : Relids subrelids;
4039 :
4040 272 : subrelids = get_relids_in_jointree(newjtloc, true, false);
4041 : Assert(!bms_is_empty(subrelids));
4042 272 : substitute_phv_relids((Node *) root->parse, varno, subrelids);
4043 272 : fix_append_rel_relids(root, varno, subrelids);
4044 : }
4045 :
4046 : /*
4047 : * We also need to remove any PlanRowMark referencing the RTE, but we
4048 : * postpone that work until we return to remove_useless_result_rtes.
4049 : */
4050 1298 : }
4051 :
4052 :
4053 : /*
4054 : * find_dependent_phvs - are there any PlaceHolderVars whose relids are
4055 : * exactly the given varno?
4056 : *
4057 : * find_dependent_phvs should be used when we want to see if there are
4058 : * any such PHVs anywhere in the Query. Another use-case is to see if
4059 : * a subtree of the join tree contains such PHVs; but for that, we have
4060 : * to look not only at the join tree nodes themselves but at the
4061 : * referenced RTEs. For that, use find_dependent_phvs_in_jointree.
4062 : */
4063 :
4064 : typedef struct
4065 : {
4066 : Relids relids;
4067 : int sublevels_up;
4068 : } find_dependent_phvs_context;
4069 :
4070 : static bool
4071 2400 : find_dependent_phvs_walker(Node *node,
4072 : find_dependent_phvs_context *context)
4073 : {
4074 2400 : if (node == NULL)
4075 564 : return false;
4076 1836 : if (IsA(node, PlaceHolderVar))
4077 : {
4078 156 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4079 :
4080 312 : if (phv->phlevelsup == context->sublevels_up &&
4081 156 : bms_equal(context->relids, phv->phrels))
4082 114 : return true;
4083 : /* fall through to examine children */
4084 : }
4085 1722 : if (IsA(node, Query))
4086 : {
4087 : /* Recurse into subselects */
4088 : bool result;
4089 :
4090 48 : context->sublevels_up++;
4091 48 : result = query_tree_walker((Query *) node,
4092 : find_dependent_phvs_walker,
4093 : context, 0);
4094 48 : context->sublevels_up--;
4095 48 : return result;
4096 : }
4097 : /* Shouldn't need to handle most planner auxiliary nodes here */
4098 : Assert(!IsA(node, SpecialJoinInfo));
4099 : Assert(!IsA(node, PlaceHolderInfo));
4100 : Assert(!IsA(node, MinMaxAggInfo));
4101 :
4102 1674 : return expression_tree_walker(node, find_dependent_phvs_walker, context);
4103 : }
4104 :
4105 : static bool
4106 90 : find_dependent_phvs(PlannerInfo *root, int varno)
4107 : {
4108 : find_dependent_phvs_context context;
4109 :
4110 : /* If there are no PHVs anywhere, we needn't work hard */
4111 90 : if (root->glob->lastPHId == 0)
4112 0 : return false;
4113 :
4114 90 : context.relids = bms_make_singleton(varno);
4115 90 : context.sublevels_up = 0;
4116 :
4117 90 : if (query_tree_walker(root->parse, find_dependent_phvs_walker, &context, 0))
4118 90 : return true;
4119 : /* The append_rel_list could be populated already, so check it too */
4120 0 : if (expression_tree_walker((Node *) root->append_rel_list,
4121 : find_dependent_phvs_walker,
4122 : &context))
4123 0 : return true;
4124 0 : return false;
4125 : }
4126 :
4127 : static bool
4128 442 : find_dependent_phvs_in_jointree(PlannerInfo *root, Node *node, int varno)
4129 : {
4130 : find_dependent_phvs_context context;
4131 : Relids subrelids;
4132 : int relid;
4133 :
4134 : /* If there are no PHVs anywhere, we needn't work hard */
4135 442 : if (root->glob->lastPHId == 0)
4136 376 : return false;
4137 :
4138 66 : context.relids = bms_make_singleton(varno);
4139 66 : context.sublevels_up = 0;
4140 :
4141 : /*
4142 : * See if the jointree fragment itself contains references (in join quals)
4143 : */
4144 66 : if (find_dependent_phvs_walker(node, &context))
4145 0 : return true;
4146 :
4147 : /*
4148 : * Otherwise, identify the set of referenced RTEs (we can ignore joins,
4149 : * since they should be flattened already, so their join alias lists no
4150 : * longer matter), and tediously check each RTE. We can ignore RTEs that
4151 : * are not marked LATERAL, though, since they couldn't possibly contain
4152 : * any cross-references to other RTEs.
4153 : */
4154 66 : subrelids = get_relids_in_jointree(node, false, false);
4155 66 : relid = -1;
4156 144 : while ((relid = bms_next_member(subrelids, relid)) >= 0)
4157 : {
4158 102 : RangeTblEntry *rte = rt_fetch(relid, root->parse->rtable);
4159 :
4160 126 : if (rte->lateral &&
4161 24 : range_table_entry_walker(rte, find_dependent_phvs_walker, &context, 0))
4162 24 : return true;
4163 : }
4164 :
4165 42 : return false;
4166 : }
4167 :
4168 : /*
4169 : * substitute_phv_relids - adjust PlaceHolderVar relid sets after pulling up
4170 : * a subquery or removing an RTE_RESULT jointree item
4171 : *
4172 : * Find any PlaceHolderVar nodes in the given tree that reference the
4173 : * pulled-up relid, and change them to reference the replacement relid(s).
4174 : *
4175 : * NOTE: although this has the form of a walker, we cheat and modify the
4176 : * nodes in-place. This should be OK since the tree was copied by
4177 : * pullup_replace_vars earlier. Avoid scribbling on the original values of
4178 : * the bitmapsets, though, because expression_tree_mutator doesn't copy those.
4179 : */
4180 :
4181 : typedef struct
4182 : {
4183 : int varno;
4184 : int sublevels_up;
4185 : Relids subrelids;
4186 : } substitute_phv_relids_context;
4187 :
4188 : static bool
4189 268862 : substitute_phv_relids_walker(Node *node,
4190 : substitute_phv_relids_context *context)
4191 : {
4192 268862 : if (node == NULL)
4193 102446 : return false;
4194 166416 : if (IsA(node, PlaceHolderVar))
4195 : {
4196 7624 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4197 :
4198 15216 : if (phv->phlevelsup == context->sublevels_up &&
4199 7592 : bms_is_member(context->varno, phv->phrels))
4200 : {
4201 10864 : phv->phrels = bms_union(phv->phrels,
4202 5432 : context->subrelids);
4203 5432 : phv->phrels = bms_del_member(phv->phrels,
4204 : context->varno);
4205 : /* Assert we haven't broken the PHV */
4206 : Assert(!bms_is_empty(phv->phrels));
4207 : }
4208 : /* fall through to examine children */
4209 : }
4210 166416 : if (IsA(node, Query))
4211 : {
4212 : /* Recurse into subselects */
4213 : bool result;
4214 :
4215 4422 : context->sublevels_up++;
4216 4422 : result = query_tree_walker((Query *) node,
4217 : substitute_phv_relids_walker,
4218 : context, 0);
4219 4422 : context->sublevels_up--;
4220 4422 : return result;
4221 : }
4222 : /* Shouldn't need to handle planner auxiliary nodes here */
4223 : Assert(!IsA(node, SpecialJoinInfo));
4224 : Assert(!IsA(node, AppendRelInfo));
4225 : Assert(!IsA(node, PlaceHolderInfo));
4226 : Assert(!IsA(node, MinMaxAggInfo));
4227 :
4228 161994 : return expression_tree_walker(node, substitute_phv_relids_walker, context);
4229 : }
4230 :
4231 : static void
4232 2418 : substitute_phv_relids(Node *node, int varno, Relids subrelids)
4233 : {
4234 : substitute_phv_relids_context context;
4235 :
4236 2418 : context.varno = varno;
4237 2418 : context.sublevels_up = 0;
4238 2418 : context.subrelids = subrelids;
4239 :
4240 : /*
4241 : * Must be prepared to start with a Query or a bare expression tree.
4242 : */
4243 2418 : query_or_expression_tree_walker(node,
4244 : substitute_phv_relids_walker,
4245 : &context,
4246 : 0);
4247 2418 : }
4248 :
4249 : /*
4250 : * fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
4251 : *
4252 : * When we pull up a subquery, any AppendRelInfo references to the subquery's
4253 : * RT index have to be replaced by the substituted relid (and there had better
4254 : * be only one). We also need to apply substitute_phv_relids to their
4255 : * translated_vars lists, since those might contain PlaceHolderVars.
4256 : *
4257 : * We assume we may modify the AppendRelInfo nodes in-place.
4258 : */
4259 : static void
4260 8432 : fix_append_rel_relids(PlannerInfo *root, int varno, Relids subrelids)
4261 : {
4262 : ListCell *l;
4263 8432 : int subvarno = -1;
4264 :
4265 : /*
4266 : * We only want to extract the member relid once, but we mustn't fail
4267 : * immediately if there are multiple members; it could be that none of the
4268 : * AppendRelInfo nodes refer to it. So compute it on first use. Note that
4269 : * bms_singleton_member will complain if set is not singleton.
4270 : */
4271 19956 : foreach(l, root->append_rel_list)
4272 : {
4273 11524 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
4274 :
4275 : /* The parent_relid shouldn't ever be a pullup target */
4276 : Assert(appinfo->parent_relid != varno);
4277 :
4278 11524 : if (appinfo->child_relid == varno)
4279 : {
4280 6230 : if (subvarno < 0)
4281 6230 : subvarno = bms_singleton_member(subrelids);
4282 6230 : appinfo->child_relid = subvarno;
4283 : }
4284 :
4285 : /* Also fix up any PHVs in its translated vars */
4286 11524 : if (root->glob->lastPHId != 0)
4287 162 : substitute_phv_relids((Node *) appinfo->translated_vars,
4288 : varno, subrelids);
4289 : }
4290 8432 : }
4291 :
4292 : /*
4293 : * get_relids_in_jointree: get set of RT indexes present in a jointree
4294 : *
4295 : * Base-relation relids are always included in the result.
4296 : * If include_outer_joins is true, outer-join RT indexes are included.
4297 : * If include_inner_joins is true, inner-join RT indexes are included.
4298 : *
4299 : * Note that for most purposes in the planner, outer joins are included
4300 : * in standard relid sets. Setting include_inner_joins true is only
4301 : * appropriate for special purposes during subquery flattening.
4302 : */
4303 : Relids
4304 93120 : get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
4305 : bool include_inner_joins)
4306 : {
4307 93120 : Relids result = NULL;
4308 :
4309 93120 : if (jtnode == NULL)
4310 0 : return result;
4311 93120 : if (IsA(jtnode, RangeTblRef))
4312 : {
4313 46972 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4314 :
4315 46972 : result = bms_make_singleton(varno);
4316 : }
4317 46148 : else if (IsA(jtnode, FromExpr))
4318 : {
4319 39908 : FromExpr *f = (FromExpr *) jtnode;
4320 : ListCell *l;
4321 :
4322 81072 : foreach(l, f->fromlist)
4323 : {
4324 41164 : result = bms_join(result,
4325 41164 : get_relids_in_jointree(lfirst(l),
4326 : include_outer_joins,
4327 : include_inner_joins));
4328 : }
4329 : }
4330 6240 : else if (IsA(jtnode, JoinExpr))
4331 : {
4332 6240 : JoinExpr *j = (JoinExpr *) jtnode;
4333 :
4334 6240 : result = get_relids_in_jointree(j->larg,
4335 : include_outer_joins,
4336 : include_inner_joins);
4337 6240 : result = bms_join(result,
4338 : get_relids_in_jointree(j->rarg,
4339 : include_outer_joins,
4340 : include_inner_joins));
4341 6240 : if (j->rtindex)
4342 : {
4343 5914 : if (j->jointype == JOIN_INNER)
4344 : {
4345 2624 : if (include_inner_joins)
4346 1026 : result = bms_add_member(result, j->rtindex);
4347 : }
4348 : else
4349 : {
4350 3290 : if (include_outer_joins)
4351 2150 : result = bms_add_member(result, j->rtindex);
4352 : }
4353 : }
4354 : }
4355 : else
4356 0 : elog(ERROR, "unrecognized node type: %d",
4357 : (int) nodeTag(jtnode));
4358 93120 : return result;
4359 : }
4360 :
4361 : /*
4362 : * get_relids_for_join: get set of base+OJ RT indexes making up a join
4363 : */
4364 : Relids
4365 358 : get_relids_for_join(Query *query, int joinrelid)
4366 : {
4367 : Node *jtnode;
4368 :
4369 358 : jtnode = find_jointree_node_for_rel((Node *) query->jointree,
4370 : joinrelid);
4371 358 : if (!jtnode)
4372 0 : elog(ERROR, "could not find join node %d", joinrelid);
4373 358 : return get_relids_in_jointree(jtnode, true, false);
4374 : }
4375 :
4376 : /*
4377 : * find_jointree_node_for_rel: locate jointree node for a base or join RT index
4378 : *
4379 : * Returns NULL if not found
4380 : */
4381 : static Node *
4382 1730 : find_jointree_node_for_rel(Node *jtnode, int relid)
4383 : {
4384 1730 : if (jtnode == NULL)
4385 0 : return NULL;
4386 1730 : if (IsA(jtnode, RangeTblRef))
4387 : {
4388 454 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4389 :
4390 454 : if (relid == varno)
4391 0 : return jtnode;
4392 : }
4393 1276 : else if (IsA(jtnode, FromExpr))
4394 : {
4395 368 : FromExpr *f = (FromExpr *) jtnode;
4396 : ListCell *l;
4397 :
4398 386 : foreach(l, f->fromlist)
4399 : {
4400 386 : jtnode = find_jointree_node_for_rel(lfirst(l), relid);
4401 386 : if (jtnode)
4402 368 : return jtnode;
4403 : }
4404 : }
4405 908 : else if (IsA(jtnode, JoinExpr))
4406 : {
4407 908 : JoinExpr *j = (JoinExpr *) jtnode;
4408 :
4409 908 : if (relid == j->rtindex)
4410 358 : return jtnode;
4411 550 : jtnode = find_jointree_node_for_rel(j->larg, relid);
4412 550 : if (jtnode)
4413 114 : return jtnode;
4414 436 : jtnode = find_jointree_node_for_rel(j->rarg, relid);
4415 436 : if (jtnode)
4416 436 : return jtnode;
4417 : }
4418 : else
4419 0 : elog(ERROR, "unrecognized node type: %d",
4420 : (int) nodeTag(jtnode));
4421 454 : return NULL;
4422 : }
4423 :
4424 : /*
4425 : * get_nullingrels: collect info about which outer joins null which relations
4426 : *
4427 : * The result struct contains, for each leaf relation used in the query,
4428 : * the set of relids of outer joins that potentially null that rel.
4429 : */
4430 : static nullingrel_info *
4431 1154 : get_nullingrels(Query *parse)
4432 : {
4433 1154 : nullingrel_info *result = palloc_object(nullingrel_info);
4434 :
4435 1154 : result->rtlength = list_length(parse->rtable);
4436 1154 : result->nullingrels = palloc0_array(Relids, result->rtlength + 1);
4437 1154 : get_nullingrels_recurse((Node *) parse->jointree, NULL, result);
4438 1154 : return result;
4439 : }
4440 :
4441 : /*
4442 : * Recursive guts of get_nullingrels().
4443 : *
4444 : * Note: at any recursion level, the passed-down upper_nullingrels must be
4445 : * treated as a constant, but it can be stored directly into *info
4446 : * if we're at leaf level. Upper recursion levels do not free their mutated
4447 : * copies of the nullingrels, because those are probably referenced by
4448 : * at least one leaf rel.
4449 : */
4450 : static void
4451 6088 : get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
4452 : nullingrel_info *info)
4453 : {
4454 6088 : if (jtnode == NULL)
4455 0 : return;
4456 6088 : if (IsA(jtnode, RangeTblRef))
4457 : {
4458 3222 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4459 :
4460 : Assert(varno > 0 && varno <= info->rtlength);
4461 3222 : info->nullingrels[varno] = upper_nullingrels;
4462 : }
4463 2866 : else if (IsA(jtnode, FromExpr))
4464 : {
4465 1238 : FromExpr *f = (FromExpr *) jtnode;
4466 : ListCell *l;
4467 :
4468 2916 : foreach(l, f->fromlist)
4469 : {
4470 1678 : get_nullingrels_recurse(lfirst(l), upper_nullingrels, info);
4471 : }
4472 : }
4473 1628 : else if (IsA(jtnode, JoinExpr))
4474 : {
4475 1628 : JoinExpr *j = (JoinExpr *) jtnode;
4476 : Relids local_nullingrels;
4477 :
4478 1628 : switch (j->jointype)
4479 : {
4480 582 : case JOIN_INNER:
4481 582 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4482 582 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4483 582 : break;
4484 1040 : case JOIN_LEFT:
4485 : case JOIN_SEMI:
4486 : case JOIN_ANTI:
4487 1040 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4488 : j->rtindex);
4489 1040 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4490 1040 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4491 1040 : break;
4492 6 : case JOIN_FULL:
4493 6 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4494 : j->rtindex);
4495 6 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4496 6 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4497 6 : break;
4498 0 : case JOIN_RIGHT:
4499 0 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4500 : j->rtindex);
4501 0 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4502 0 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4503 0 : break;
4504 0 : default:
4505 0 : elog(ERROR, "unrecognized join type: %d",
4506 : (int) j->jointype);
4507 : break;
4508 : }
4509 : }
4510 : else
4511 0 : elog(ERROR, "unrecognized node type: %d",
4512 : (int) nodeTag(jtnode));
4513 : }
|
