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) 1996-2026, 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 : Relids nullable_rels; /* base relids that are nullable within this
92 : * subtree */
93 : List *sub_states; /* List of states for subtree components */
94 : } reduce_outer_joins_pass1_state;
95 :
96 : typedef struct reduce_outer_joins_pass2_state
97 : {
98 : Relids inner_reduced; /* OJ relids reduced to plain inner joins */
99 : List *partial_reduced; /* List of partially reduced FULL joins */
100 : } reduce_outer_joins_pass2_state;
101 :
102 : typedef struct reduce_outer_joins_partial_state
103 : {
104 : int full_join_rti; /* RT index of a formerly-FULL join */
105 : Relids unreduced_side; /* relids in its still-nullable side */
106 : } reduce_outer_joins_partial_state;
107 :
108 : static Query *expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
109 : RangeTblEntry *rte, int rt_index,
110 : Relation relation);
111 : static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
112 : Relids *relids);
113 : static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
114 : Node **jtlink1, Relids available_rels1,
115 : Node **jtlink2, Relids available_rels2);
116 : static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
117 : JoinExpr *lowest_outer_join,
118 : AppendRelInfo *containing_appendrel);
119 : static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
120 : RangeTblEntry *rte,
121 : JoinExpr *lowest_outer_join,
122 : AppendRelInfo *containing_appendrel);
123 : static Node *pull_up_simple_union_all(PlannerInfo *root, Node *jtnode,
124 : RangeTblEntry *rte);
125 : static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
126 : int parentRTindex, Query *setOpQuery,
127 : int childRToffset);
128 : static void make_setop_translation_list(Query *query, int newvarno,
129 : AppendRelInfo *appinfo);
130 : static bool is_simple_subquery(PlannerInfo *root, Query *subquery,
131 : RangeTblEntry *rte,
132 : JoinExpr *lowest_outer_join);
133 : static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
134 : RangeTblEntry *rte);
135 : static bool is_simple_values(PlannerInfo *root, RangeTblEntry *rte);
136 : static Node *pull_up_constant_function(PlannerInfo *root, Node *jtnode,
137 : RangeTblEntry *rte,
138 : AppendRelInfo *containing_appendrel);
139 : static bool is_simple_union_all(Query *subquery);
140 : static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery,
141 : List *colTypes);
142 : static bool is_safe_append_member(Query *subquery);
143 : static bool jointree_contains_lateral_outer_refs(PlannerInfo *root,
144 : Node *jtnode, bool restricted,
145 : Relids safe_upper_varnos);
146 : static void perform_pullup_replace_vars(PlannerInfo *root,
147 : pullup_replace_vars_context *rvcontext,
148 : AppendRelInfo *containing_appendrel);
149 : static void replace_vars_in_jointree(Node *jtnode,
150 : pullup_replace_vars_context *context);
151 : static Node *pullup_replace_vars(Node *expr,
152 : pullup_replace_vars_context *context);
153 : static Node *pullup_replace_vars_callback(const Var *var,
154 : replace_rte_variables_context *context);
155 : static Query *pullup_replace_vars_subquery(Query *query,
156 : pullup_replace_vars_context *context);
157 : static reduce_outer_joins_pass1_state *reduce_outer_joins_pass1(Node *jtnode);
158 : static void reduce_outer_joins_pass2(Node *jtnode,
159 : reduce_outer_joins_pass1_state *state1,
160 : reduce_outer_joins_pass2_state *state2,
161 : PlannerInfo *root,
162 : Relids nonnullable_rels,
163 : List *forced_null_vars);
164 : static void report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
165 : int rtindex, Relids relids);
166 : static bool has_notnull_forced_var(PlannerInfo *root, List *forced_null_vars,
167 : reduce_outer_joins_pass1_state *right_state);
168 : static Node *remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
169 : Node **parent_quals,
170 : Relids *dropped_outer_joins);
171 : static int get_result_relid(PlannerInfo *root, Node *jtnode);
172 : static void remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc);
173 : static bool find_dependent_phvs(PlannerInfo *root, int varno);
174 : static bool find_dependent_phvs_in_jointree(PlannerInfo *root,
175 : Node *node, int varno);
176 : static void substitute_phv_relids(Node *node,
177 : int varno, Relids subrelids);
178 : static void fix_append_rel_relids(PlannerInfo *root, int varno,
179 : Relids subrelids);
180 : static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
181 : static nullingrel_info *get_nullingrels(Query *parse);
182 : static void get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
183 : nullingrel_info *info);
184 :
185 :
186 : /*
187 : * transform_MERGE_to_join
188 : * Replace a MERGE's jointree to also include the target relation.
189 : */
190 : void
191 395919 : transform_MERGE_to_join(Query *parse)
192 : {
193 : RangeTblEntry *joinrte;
194 : JoinExpr *joinexpr;
195 : bool have_action[NUM_MERGE_MATCH_KINDS];
196 : JoinType jointype;
197 : int joinrti;
198 : List *vars;
199 : RangeTblRef *rtr;
200 : FromExpr *target;
201 : Node *source;
202 : int sourcerti;
203 :
204 395919 : if (parse->commandType != CMD_MERGE)
205 394364 : return;
206 :
207 : /* XXX probably bogus */
208 1555 : vars = NIL;
209 :
210 : /*
211 : * Work out what kind of join is required. If there any WHEN NOT MATCHED
212 : * BY SOURCE/TARGET actions, an outer join is required so that we process
213 : * all unmatched tuples from the source and/or target relations.
214 : * Otherwise, we can use an inner join.
215 : */
216 1555 : have_action[MERGE_WHEN_MATCHED] = false;
217 1555 : have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = false;
218 1555 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = false;
219 :
220 5446 : foreach_node(MergeAction, action, parse->mergeActionList)
221 : {
222 2336 : if (action->commandType != CMD_NOTHING)
223 2268 : have_action[action->matchKind] = true;
224 : }
225 :
226 1555 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] &&
227 105 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
228 80 : jointype = JOIN_FULL;
229 1475 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
230 25 : jointype = JOIN_LEFT;
231 1450 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
232 669 : jointype = JOIN_RIGHT;
233 : else
234 781 : jointype = JOIN_INNER;
235 :
236 : /* Manufacture a join RTE to use. */
237 1555 : joinrte = makeNode(RangeTblEntry);
238 1555 : joinrte->rtekind = RTE_JOIN;
239 1555 : joinrte->jointype = jointype;
240 1555 : joinrte->joinmergedcols = 0;
241 1555 : joinrte->joinaliasvars = vars;
242 1555 : joinrte->joinleftcols = NIL; /* MERGE does not allow JOIN USING */
243 1555 : joinrte->joinrightcols = NIL; /* ditto */
244 1555 : joinrte->join_using_alias = NULL;
245 :
246 1555 : joinrte->alias = NULL;
247 1555 : joinrte->eref = makeAlias("*MERGE*", NIL);
248 1555 : joinrte->lateral = false;
249 1555 : joinrte->inh = false;
250 1555 : joinrte->inFromCl = true;
251 :
252 : /*
253 : * Add completed RTE to pstate's range table list, so that we know its
254 : * index.
255 : */
256 1555 : parse->rtable = lappend(parse->rtable, joinrte);
257 1555 : joinrti = list_length(parse->rtable);
258 :
259 : /*
260 : * Create a JOIN between the target and the source relation.
261 : *
262 : * Here the target is identified by parse->mergeTargetRelation. For a
263 : * regular table, this will equal parse->resultRelation, but for a
264 : * trigger-updatable view, it will be the expanded view subquery that we
265 : * need to pull data from.
266 : *
267 : * The source relation is in parse->jointree->fromlist, but any quals in
268 : * parse->jointree->quals are restrictions on the target relation (if the
269 : * target relation is an auto-updatable view).
270 : */
271 : /* target rel, with any quals */
272 1555 : rtr = makeNode(RangeTblRef);
273 1555 : rtr->rtindex = parse->mergeTargetRelation;
274 1555 : target = makeFromExpr(list_make1(rtr), parse->jointree->quals);
275 :
276 : /* source rel (expect exactly one -- see transformMergeStmt()) */
277 : Assert(list_length(parse->jointree->fromlist) == 1);
278 1555 : source = linitial(parse->jointree->fromlist);
279 :
280 : /*
281 : * index of source rel (expect either a RangeTblRef or a JoinExpr -- see
282 : * transformFromClauseItem()).
283 : */
284 1555 : if (IsA(source, RangeTblRef))
285 1485 : sourcerti = ((RangeTblRef *) source)->rtindex;
286 70 : else if (IsA(source, JoinExpr))
287 70 : sourcerti = ((JoinExpr *) source)->rtindex;
288 : else
289 : {
290 0 : elog(ERROR, "unrecognized source node type: %d",
291 : (int) nodeTag(source));
292 : sourcerti = 0; /* keep compiler quiet */
293 : }
294 :
295 : /* Join the source and target */
296 1555 : joinexpr = makeNode(JoinExpr);
297 1555 : joinexpr->jointype = jointype;
298 1555 : joinexpr->isNatural = false;
299 1555 : joinexpr->larg = (Node *) target;
300 1555 : joinexpr->rarg = source;
301 1555 : joinexpr->usingClause = NIL;
302 1555 : joinexpr->join_using_alias = NULL;
303 1555 : joinexpr->quals = parse->mergeJoinCondition;
304 1555 : joinexpr->alias = NULL;
305 1555 : joinexpr->rtindex = joinrti;
306 :
307 : /* Make the new join be the sole entry in the query's jointree */
308 1555 : parse->jointree->fromlist = list_make1(joinexpr);
309 1555 : parse->jointree->quals = NULL;
310 :
311 : /*
312 : * If necessary, mark parse->targetlist entries that refer to the target
313 : * as nullable by the join. Normally the targetlist will be empty for a
314 : * MERGE, but if the target is a trigger-updatable view, it will contain a
315 : * whole-row Var referring to the expanded view query.
316 : */
317 1555 : if (parse->targetList != NIL &&
318 35 : (jointype == JOIN_RIGHT || jointype == JOIN_FULL))
319 35 : parse->targetList = (List *)
320 35 : add_nulling_relids((Node *) parse->targetList,
321 35 : bms_make_singleton(parse->mergeTargetRelation),
322 35 : bms_make_singleton(joinrti));
323 :
324 : /*
325 : * If the source relation is on the outer side of the join, mark any
326 : * source relation Vars in the join condition, actions, and RETURNING list
327 : * as nullable by the join. These Vars will be added to the targetlist by
328 : * preprocess_targetlist(), so it's important to mark them correctly here.
329 : *
330 : * It might seem that this is not necessary for Vars in the join
331 : * condition, since it is inside the join, but it is also needed above the
332 : * join (in the ModifyTable node) to distinguish between the MATCHED and
333 : * NOT MATCHED BY SOURCE cases -- see ExecMergeMatched(). Note that this
334 : * creates a modified copy of the join condition, for use above the join,
335 : * without modifying the original join condition, inside the join.
336 : */
337 1555 : if (jointype == JOIN_LEFT || jointype == JOIN_FULL)
338 : {
339 105 : parse->mergeJoinCondition =
340 105 : add_nulling_relids(parse->mergeJoinCondition,
341 105 : bms_make_singleton(sourcerti),
342 105 : bms_make_singleton(joinrti));
343 :
344 500 : foreach_node(MergeAction, action, parse->mergeActionList)
345 : {
346 290 : action->qual =
347 290 : add_nulling_relids(action->qual,
348 290 : bms_make_singleton(sourcerti),
349 290 : bms_make_singleton(joinrti));
350 :
351 290 : action->targetList = (List *)
352 290 : add_nulling_relids((Node *) action->targetList,
353 290 : bms_make_singleton(sourcerti),
354 290 : bms_make_singleton(joinrti));
355 : }
356 :
357 105 : parse->returningList = (List *)
358 105 : add_nulling_relids((Node *) parse->returningList,
359 105 : bms_make_singleton(sourcerti),
360 105 : bms_make_singleton(joinrti));
361 : }
362 :
363 : /*
364 : * If there are any WHEN NOT MATCHED BY SOURCE actions, the executor will
365 : * use the join condition to distinguish between MATCHED and NOT MATCHED
366 : * BY SOURCE cases. Otherwise, it's no longer needed, and we set it to
367 : * NULL, saving cycles during planning and execution.
368 : *
369 : * We need to be careful though: the executor evaluates this condition
370 : * using the output of the join subplan node, which nulls the output from
371 : * the source relation when the join condition doesn't match. That risks
372 : * producing incorrect results when rechecking using a "non-strict" join
373 : * condition, such as "src.col IS NOT DISTINCT FROM tgt.col". To guard
374 : * against that, we add an additional "src IS NOT NULL" check to the join
375 : * condition, so that it does the right thing when performing a recheck
376 : * based on the output of the join subplan.
377 : */
378 1555 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
379 : {
380 : Var *var;
381 : NullTest *ntest;
382 :
383 : /* source wholerow Var (nullable by the new join) */
384 105 : var = makeWholeRowVar(rt_fetch(sourcerti, parse->rtable),
385 : sourcerti, 0, false);
386 105 : var->varnullingrels = bms_make_singleton(joinrti);
387 :
388 : /* "src IS NOT NULL" check */
389 105 : ntest = makeNode(NullTest);
390 105 : ntest->arg = (Expr *) var;
391 105 : ntest->nulltesttype = IS_NOT_NULL;
392 105 : ntest->argisrow = false;
393 105 : ntest->location = -1;
394 :
395 : /* combine it with the original join condition */
396 105 : parse->mergeJoinCondition =
397 105 : (Node *) make_and_qual((Node *) ntest, parse->mergeJoinCondition);
398 : }
399 : else
400 1450 : parse->mergeJoinCondition = NULL; /* join condition not needed */
401 : }
402 :
403 : /*
404 : * preprocess_relation_rtes
405 : * Do the preprocessing work for any relation RTEs in the FROM clause.
406 : *
407 : * This scans the rangetable for relation RTEs and retrieves the necessary
408 : * catalog information for each relation. Using this information, it clears
409 : * the inh flag for any relation that has no children, collects not-null
410 : * attribute numbers for any relation that has column not-null constraints, and
411 : * expands virtual generated columns for any relation that contains them.
412 : *
413 : * Note that expanding virtual generated columns may cause the query tree to
414 : * have new copies of rangetable entries. Therefore, we have to use list_nth
415 : * instead of foreach when iterating over the query's rangetable.
416 : *
417 : * Returns a modified copy of the query tree, if any relations with virtual
418 : * generated columns are present.
419 : */
420 : Query *
421 430146 : preprocess_relation_rtes(PlannerInfo *root)
422 : {
423 430146 : Query *parse = root->parse;
424 : int rtable_size;
425 : int rt_index;
426 :
427 430146 : rtable_size = list_length(parse->rtable);
428 :
429 975338 : for (rt_index = 0; rt_index < rtable_size; rt_index++)
430 : {
431 545192 : RangeTblEntry *rte = rt_fetch(rt_index + 1, parse->rtable);
432 : Relation relation;
433 :
434 : /* We only care about relation RTEs. */
435 545192 : if (rte->rtekind != RTE_RELATION)
436 176874 : continue;
437 :
438 : /*
439 : * We need not lock the relation since it was already locked by the
440 : * rewriter.
441 : */
442 368318 : relation = table_open(rte->relid, NoLock);
443 :
444 : /*
445 : * Check to see if the relation actually has any children; if not,
446 : * clear the inh flag so we can treat it as a plain base relation.
447 : *
448 : * Note: this could give a false-positive result, if the rel once had
449 : * children but no longer does. We used to be able to clear rte->inh
450 : * later on when we discovered that, but no more; we have to handle
451 : * such cases as full-fledged inheritance.
452 : */
453 368318 : if (rte->inh)
454 308272 : rte->inh = relation->rd_rel->relhassubclass;
455 :
456 : /*
457 : * Check to see if the relation has any column not-null constraints;
458 : * if so, retrieve the constraint information and store it in a
459 : * relation OID based hash table.
460 : */
461 368318 : get_relation_notnullatts(root, relation);
462 :
463 : /*
464 : * Check to see if the relation has any virtual generated columns; if
465 : * so, replace all Var nodes in the query that reference these columns
466 : * with the generation expressions.
467 : */
468 368318 : parse = expand_virtual_generated_columns(root, parse,
469 : rte, rt_index + 1,
470 : relation);
471 :
472 368318 : table_close(relation, NoLock);
473 : }
474 :
475 430146 : return parse;
476 : }
477 :
478 : /*
479 : * expand_virtual_generated_columns
480 : * Expand virtual generated columns for the given relation.
481 : *
482 : * This checks whether the given relation has any virtual generated columns,
483 : * and if so, replaces all Var nodes in the query that reference those columns
484 : * with their generation expressions.
485 : *
486 : * Returns a modified copy of the query tree if the relation contains virtual
487 : * generated columns.
488 : */
489 : static Query *
490 368318 : expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
491 : RangeTblEntry *rte, int rt_index,
492 : Relation relation)
493 : {
494 : TupleDesc tupdesc;
495 :
496 : /* Only normal relations can have virtual generated columns */
497 : Assert(rte->rtekind == RTE_RELATION);
498 :
499 368318 : tupdesc = RelationGetDescr(relation);
500 368318 : if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
501 : {
502 885 : List *tlist = NIL;
503 : pullup_replace_vars_context rvcontext;
504 :
505 3476 : for (int i = 0; i < tupdesc->natts; i++)
506 : {
507 2591 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
508 : TargetEntry *tle;
509 :
510 2591 : if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
511 : {
512 : Node *defexpr;
513 :
514 1170 : defexpr = build_generation_expression(relation, i + 1);
515 1170 : ChangeVarNodes(defexpr, 1, rt_index, 0);
516 :
517 1170 : tle = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
518 1170 : tlist = lappend(tlist, tle);
519 : }
520 : else
521 : {
522 : Var *var;
523 :
524 1421 : var = makeVar(rt_index,
525 1421 : i + 1,
526 : attr->atttypid,
527 : attr->atttypmod,
528 : attr->attcollation,
529 : 0);
530 :
531 1421 : tle = makeTargetEntry((Expr *) var, i + 1, 0, false);
532 1421 : tlist = lappend(tlist, tle);
533 : }
534 : }
535 :
536 : Assert(list_length(tlist) > 0);
537 : Assert(!rte->lateral);
538 :
539 : /*
540 : * The relation's targetlist items are now in the appropriate form to
541 : * insert into the query, except that we may need to wrap them in
542 : * PlaceHolderVars. Set up required context data for
543 : * pullup_replace_vars.
544 : */
545 885 : rvcontext.root = root;
546 885 : rvcontext.targetlist = tlist;
547 885 : rvcontext.target_rte = rte;
548 885 : rvcontext.result_relation = parse->resultRelation;
549 : /* won't need these values */
550 885 : rvcontext.relids = NULL;
551 885 : rvcontext.nullinfo = NULL;
552 : /* pass NULL for outer_hasSubLinks */
553 885 : rvcontext.outer_hasSubLinks = NULL;
554 885 : rvcontext.varno = rt_index;
555 : /* this flag will be set below, if needed */
556 885 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
557 : /* initialize cache array with indexes 0 .. length(tlist) */
558 885 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
559 : sizeof(Node *));
560 :
561 : /*
562 : * If the query uses grouping sets, we need a PlaceHolderVar for each
563 : * expression of the relation's targetlist items. (See comments in
564 : * pull_up_simple_subquery().)
565 : */
566 885 : if (parse->groupingSets)
567 10 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
568 :
569 : /*
570 : * Apply pullup variable replacement throughout the query tree.
571 : */
572 885 : parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
573 : }
574 :
575 368318 : return parse;
576 : }
577 :
578 : /*
579 : * replace_empty_jointree
580 : * If the Query's jointree is empty, replace it with a dummy RTE_RESULT
581 : * relation.
582 : *
583 : * By doing this, we can avoid a bunch of corner cases that formerly existed
584 : * for SELECTs with omitted FROM clauses. An example is that a subquery
585 : * with empty jointree previously could not be pulled up, because that would
586 : * have resulted in an empty relid set, making the subquery not uniquely
587 : * identifiable for join or PlaceHolderVar processing.
588 : *
589 : * Unlike most other functions in this file, this function doesn't recurse;
590 : * we rely on other processing to invoke it on sub-queries at suitable times.
591 : */
592 : void
593 430146 : replace_empty_jointree(Query *parse)
594 : {
595 : RangeTblEntry *rte;
596 : Index rti;
597 : RangeTblRef *rtr;
598 :
599 : /* Nothing to do if jointree is already nonempty */
600 430146 : if (parse->jointree->fromlist != NIL)
601 289536 : return;
602 :
603 : /* We mustn't change it in the top level of a setop tree, either */
604 146065 : if (parse->setOperations)
605 5455 : return;
606 :
607 : /* Create suitable RTE */
608 140610 : rte = makeNode(RangeTblEntry);
609 140610 : rte->rtekind = RTE_RESULT;
610 140610 : rte->eref = makeAlias("*RESULT*", NIL);
611 :
612 : /* Add it to rangetable */
613 140610 : parse->rtable = lappend(parse->rtable, rte);
614 140610 : rti = list_length(parse->rtable);
615 :
616 : /* And jam a reference into the jointree */
617 140610 : rtr = makeNode(RangeTblRef);
618 140610 : rtr->rtindex = rti;
619 140610 : parse->jointree->fromlist = list_make1(rtr);
620 : }
621 :
622 : /*
623 : * pull_up_sublinks
624 : * Attempt to pull up ANY and EXISTS SubLinks to be treated as
625 : * semijoins or anti-semijoins.
626 : *
627 : * A clause "foo op ANY (sub-SELECT)" can be processed by pulling the
628 : * sub-SELECT up to become a rangetable entry and treating the implied
629 : * comparisons as quals of a semijoin. However, this optimization *only*
630 : * works at the top level of WHERE or a JOIN/ON clause, because we cannot
631 : * distinguish whether the ANY ought to return FALSE or NULL in cases
632 : * involving NULL inputs. Also, in an outer join's ON clause we can only
633 : * do this if the sublink is degenerate (ie, references only the nullable
634 : * side of the join). In that case it is legal to push the semijoin
635 : * down into the nullable side of the join. If the sublink references any
636 : * nonnullable-side variables then it would have to be evaluated as part
637 : * of the outer join, which makes things way too complicated.
638 : *
639 : * Under similar conditions, EXISTS and NOT EXISTS clauses can be handled
640 : * by pulling up the sub-SELECT and creating a semijoin or anti-semijoin.
641 : *
642 : * This routine searches for such clauses and does the necessary parsetree
643 : * transformations if any are found.
644 : *
645 : * This routine has to run before preprocess_expression(), so the quals
646 : * clauses are not yet reduced to implicit-AND format, and are not guaranteed
647 : * to be AND/OR-flat either. That means we need to recursively search through
648 : * explicit AND clauses. We stop as soon as we hit a non-AND item.
649 : */
650 : void
651 32690 : pull_up_sublinks(PlannerInfo *root)
652 : {
653 : Node *jtnode;
654 : Relids relids;
655 :
656 : /* Begin recursion through the jointree */
657 32690 : jtnode = pull_up_sublinks_jointree_recurse(root,
658 32690 : (Node *) root->parse->jointree,
659 : &relids);
660 :
661 : /*
662 : * root->parse->jointree must always be a FromExpr, so insert a dummy one
663 : * if we got a bare RangeTblRef or JoinExpr out of the recursion.
664 : */
665 32690 : if (IsA(jtnode, FromExpr))
666 23851 : root->parse->jointree = (FromExpr *) jtnode;
667 : else
668 8839 : root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
669 32690 : }
670 :
671 : /*
672 : * Recurse through jointree nodes for pull_up_sublinks()
673 : *
674 : * In addition to returning the possibly-modified jointree node, we return
675 : * a relids set of the contained rels into *relids.
676 : */
677 : static Node *
678 110523 : pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
679 : Relids *relids)
680 : {
681 : /* Since this function recurses, it could be driven to stack overflow. */
682 110523 : check_stack_depth();
683 :
684 110523 : if (jtnode == NULL)
685 : {
686 0 : *relids = NULL;
687 : }
688 110523 : else if (IsA(jtnode, RangeTblRef))
689 : {
690 61033 : int varno = ((RangeTblRef *) jtnode)->rtindex;
691 :
692 61033 : *relids = bms_make_singleton(varno);
693 : /* jtnode is returned unmodified */
694 : }
695 49490 : else if (IsA(jtnode, FromExpr))
696 : {
697 32880 : FromExpr *f = (FromExpr *) jtnode;
698 32880 : List *newfromlist = NIL;
699 32880 : Relids frelids = NULL;
700 : FromExpr *newf;
701 : Node *jtlink;
702 : ListCell *l;
703 :
704 : /* First, recurse to process children and collect their relids */
705 68515 : foreach(l, f->fromlist)
706 : {
707 : Node *newchild;
708 : Relids childrelids;
709 :
710 35635 : newchild = pull_up_sublinks_jointree_recurse(root,
711 35635 : lfirst(l),
712 : &childrelids);
713 35635 : newfromlist = lappend(newfromlist, newchild);
714 35635 : frelids = bms_join(frelids, childrelids);
715 : }
716 : /* Build the replacement FromExpr; no quals yet */
717 32880 : newf = makeFromExpr(newfromlist, NULL);
718 : /* Set up a link representing the rebuilt jointree */
719 32880 : jtlink = (Node *) newf;
720 : /* Now process qual --- all children are available for use */
721 32880 : newf->quals = pull_up_sublinks_qual_recurse(root, f->quals,
722 : &jtlink, frelids,
723 : NULL, NULL);
724 :
725 : /*
726 : * Note that the result will be either newf, or a stack of JoinExprs
727 : * with newf at the base. We rely on subsequent optimization steps to
728 : * flatten this and rearrange the joins as needed.
729 : *
730 : * Although we could include the pulled-up subqueries in the returned
731 : * relids, there's no need since upper quals couldn't refer to their
732 : * outputs anyway.
733 : */
734 32880 : *relids = frelids;
735 32880 : jtnode = jtlink;
736 : }
737 16610 : else if (IsA(jtnode, JoinExpr))
738 : {
739 : JoinExpr *j;
740 : Relids leftrelids;
741 : Relids rightrelids;
742 : Node *jtlink;
743 :
744 : /*
745 : * Make a modifiable copy of join node, but don't bother copying its
746 : * subnodes (yet).
747 : */
748 16610 : j = palloc_object(JoinExpr);
749 16610 : memcpy(j, jtnode, sizeof(JoinExpr));
750 16610 : jtlink = (Node *) j;
751 :
752 : /* Recurse to process children and collect their relids */
753 16610 : j->larg = pull_up_sublinks_jointree_recurse(root, j->larg,
754 : &leftrelids);
755 16610 : j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg,
756 : &rightrelids);
757 :
758 : /*
759 : * Now process qual, showing appropriate child relids as available,
760 : * and attach any pulled-up jointree items at the right place. In the
761 : * inner-join case we put new JoinExprs above the existing one (much
762 : * as for a FromExpr-style join). In outer-join cases the new
763 : * JoinExprs must go into the nullable side of the outer join. The
764 : * point of the available_rels machinations is to ensure that we only
765 : * pull up quals for which that's okay.
766 : *
767 : * We don't expect to see any pre-existing JOIN_SEMI, JOIN_ANTI,
768 : * JOIN_RIGHT_SEMI, or JOIN_RIGHT_ANTI jointypes here.
769 : */
770 16610 : switch (j->jointype)
771 : {
772 7734 : case JOIN_INNER:
773 7734 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
774 : &jtlink,
775 : bms_union(leftrelids,
776 : rightrelids),
777 : NULL, NULL);
778 7734 : break;
779 8776 : case JOIN_LEFT:
780 8776 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
781 : &j->rarg,
782 : rightrelids,
783 : NULL, NULL);
784 8776 : break;
785 20 : case JOIN_FULL:
786 : /* can't do anything with full-join quals */
787 20 : break;
788 80 : case JOIN_RIGHT:
789 80 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
790 : &j->larg,
791 : leftrelids,
792 : NULL, NULL);
793 80 : break;
794 0 : default:
795 0 : elog(ERROR, "unrecognized join type: %d",
796 : (int) j->jointype);
797 : break;
798 : }
799 :
800 : /*
801 : * Although we could include the pulled-up subqueries in the returned
802 : * relids, there's no need since upper quals couldn't refer to their
803 : * outputs anyway. But we *do* need to include the join's own rtindex
804 : * because we haven't yet collapsed join alias variables, so upper
805 : * levels would mistakenly think they couldn't use references to this
806 : * join.
807 : */
808 16610 : *relids = bms_join(leftrelids, rightrelids);
809 16610 : if (j->rtindex)
810 16610 : *relids = bms_add_member(*relids, j->rtindex);
811 16610 : jtnode = jtlink;
812 : }
813 : else
814 0 : elog(ERROR, "unrecognized node type: %d",
815 : (int) nodeTag(jtnode));
816 110523 : return jtnode;
817 : }
818 :
819 : /*
820 : * Recurse through top-level qual nodes for pull_up_sublinks()
821 : *
822 : * jtlink1 points to the link in the jointree where any new JoinExprs should
823 : * be inserted if they reference available_rels1 (i.e., available_rels1
824 : * denotes the relations present underneath jtlink1). Optionally, jtlink2 can
825 : * point to a second link where new JoinExprs should be inserted if they
826 : * reference available_rels2 (pass NULL for both those arguments if not used).
827 : * Note that SubLinks referencing both sets of variables cannot be optimized.
828 : * If we find multiple pull-up-able SubLinks, they'll get stacked onto jtlink1
829 : * and/or jtlink2 in the order we encounter them. We rely on subsequent
830 : * optimization to rearrange the stack if appropriate.
831 : *
832 : * Returns the replacement qual node, or NULL if the qual should be removed.
833 : */
834 : static Node *
835 121166 : pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
836 : Node **jtlink1, Relids available_rels1,
837 : Node **jtlink2, Relids available_rels2)
838 : {
839 121166 : if (node == NULL)
840 5013 : return NULL;
841 116153 : if (IsA(node, SubLink))
842 : {
843 4444 : SubLink *sublink = (SubLink *) node;
844 : JoinExpr *j;
845 : Relids child_rels;
846 :
847 : /* Is it a convertible ANY or EXISTS clause? */
848 4444 : if (sublink->subLinkType == ANY_SUBLINK)
849 : {
850 : ScalarArrayOpExpr *saop;
851 :
852 3785 : if ((saop = convert_VALUES_to_ANY(root,
853 : sublink->testexpr,
854 3785 : (Query *) sublink->subselect)) != NULL)
855 : {
856 : /*
857 : * The VALUES sequence was simplified. Nothing more to do
858 : * here.
859 : */
860 70 : return (Node *) saop;
861 : }
862 :
863 3715 : if ((j = convert_ANY_sublink_to_join(root, sublink, false,
864 : available_rels1)) != NULL)
865 : {
866 : /* Yes; insert the new join node into the join tree */
867 3628 : j->larg = *jtlink1;
868 3628 : *jtlink1 = (Node *) j;
869 : /* Recursively process pulled-up jointree nodes */
870 3628 : j->rarg = pull_up_sublinks_jointree_recurse(root,
871 : j->rarg,
872 : &child_rels);
873 :
874 : /*
875 : * Now recursively process the pulled-up quals. Any inserted
876 : * joins can get stacked onto either j->larg or j->rarg,
877 : * depending on which rels they reference.
878 : */
879 3628 : j->quals = pull_up_sublinks_qual_recurse(root,
880 : j->quals,
881 : &j->larg,
882 : available_rels1,
883 : &j->rarg,
884 : child_rels);
885 : /* Return NULL representing constant TRUE */
886 3628 : return NULL;
887 : }
888 92 : if (available_rels2 != NULL &&
889 5 : (j = convert_ANY_sublink_to_join(root, sublink, false,
890 : available_rels2)) != NULL)
891 : {
892 : /* Yes; insert the new join node into the join tree */
893 0 : j->larg = *jtlink2;
894 0 : *jtlink2 = (Node *) j;
895 : /* Recursively process pulled-up jointree nodes */
896 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
897 : j->rarg,
898 : &child_rels);
899 :
900 : /*
901 : * Now recursively process the pulled-up quals. Any inserted
902 : * joins can get stacked onto either j->larg or j->rarg,
903 : * depending on which rels they reference.
904 : */
905 0 : j->quals = pull_up_sublinks_qual_recurse(root,
906 : j->quals,
907 : &j->larg,
908 : available_rels2,
909 : &j->rarg,
910 : child_rels);
911 : /* Return NULL representing constant TRUE */
912 0 : return NULL;
913 : }
914 : }
915 659 : else if (sublink->subLinkType == EXISTS_SUBLINK)
916 : {
917 609 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, false,
918 : available_rels1)) != NULL)
919 : {
920 : /* Yes; insert the new join node into the join tree */
921 499 : j->larg = *jtlink1;
922 499 : *jtlink1 = (Node *) j;
923 : /* Recursively process pulled-up jointree nodes */
924 499 : j->rarg = pull_up_sublinks_jointree_recurse(root,
925 : j->rarg,
926 : &child_rels);
927 :
928 : /*
929 : * Now recursively process the pulled-up quals. Any inserted
930 : * joins can get stacked onto either j->larg or j->rarg,
931 : * depending on which rels they reference.
932 : */
933 499 : j->quals = pull_up_sublinks_qual_recurse(root,
934 : j->quals,
935 : &j->larg,
936 : available_rels1,
937 : &j->rarg,
938 : child_rels);
939 : /* Return NULL representing constant TRUE */
940 499 : return NULL;
941 : }
942 126 : if (available_rels2 != NULL &&
943 16 : (j = convert_EXISTS_sublink_to_join(root, sublink, false,
944 : available_rels2)) != NULL)
945 : {
946 : /* Yes; insert the new join node into the join tree */
947 16 : j->larg = *jtlink2;
948 16 : *jtlink2 = (Node *) j;
949 : /* Recursively process pulled-up jointree nodes */
950 16 : j->rarg = pull_up_sublinks_jointree_recurse(root,
951 : j->rarg,
952 : &child_rels);
953 :
954 : /*
955 : * Now recursively process the pulled-up quals. Any inserted
956 : * joins can get stacked onto either j->larg or j->rarg,
957 : * depending on which rels they reference.
958 : */
959 16 : j->quals = pull_up_sublinks_qual_recurse(root,
960 : j->quals,
961 : &j->larg,
962 : available_rels2,
963 : &j->rarg,
964 : child_rels);
965 : /* Return NULL representing constant TRUE */
966 16 : return NULL;
967 : }
968 : }
969 : /* Else return it unmodified */
970 231 : return node;
971 : }
972 111709 : if (is_notclause(node))
973 : {
974 : /* If the immediate argument of NOT is ANY or EXISTS, try to convert */
975 11901 : SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
976 : JoinExpr *j;
977 : Relids child_rels;
978 :
979 11901 : if (sublink && IsA(sublink, SubLink))
980 : {
981 4969 : if (sublink->subLinkType == ANY_SUBLINK)
982 : {
983 200 : if ((j = convert_ANY_sublink_to_join(root, sublink, true,
984 : available_rels1)) != NULL)
985 : {
986 : /* Yes; insert the new join node into the join tree */
987 75 : j->larg = *jtlink1;
988 75 : *jtlink1 = (Node *) j;
989 : /* Recursively process pulled-up jointree nodes */
990 75 : j->rarg = pull_up_sublinks_jointree_recurse(root,
991 : j->rarg,
992 : &child_rels);
993 :
994 : /*
995 : * Now recursively process the pulled-up quals. Because
996 : * we are underneath a NOT, we can't pull up sublinks that
997 : * reference the left-hand stuff, but it's still okay to
998 : * pull up sublinks referencing j->rarg.
999 : */
1000 75 : j->quals = pull_up_sublinks_qual_recurse(root,
1001 : j->quals,
1002 : &j->rarg,
1003 : child_rels,
1004 : NULL, NULL);
1005 : /* Return NULL representing constant TRUE */
1006 75 : return NULL;
1007 : }
1008 125 : if (available_rels2 != NULL &&
1009 0 : (j = convert_ANY_sublink_to_join(root, sublink, true,
1010 : available_rels2)) != NULL)
1011 : {
1012 : /* Yes; insert the new join node into the join tree */
1013 0 : j->larg = *jtlink2;
1014 0 : *jtlink2 = (Node *) j;
1015 : /* Recursively process pulled-up jointree nodes */
1016 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1017 : j->rarg,
1018 : &child_rels);
1019 :
1020 : /*
1021 : * Now recursively process the pulled-up quals. Because
1022 : * we are underneath a NOT, we can't pull up sublinks that
1023 : * reference the left-hand stuff, but it's still okay to
1024 : * pull up sublinks referencing j->rarg.
1025 : */
1026 0 : j->quals = pull_up_sublinks_qual_recurse(root,
1027 : j->quals,
1028 : &j->rarg,
1029 : child_rels,
1030 : NULL, NULL);
1031 : /* Return NULL representing constant TRUE */
1032 0 : return NULL;
1033 : }
1034 : }
1035 4769 : else if (sublink->subLinkType == EXISTS_SUBLINK)
1036 : {
1037 4769 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, true,
1038 : available_rels1)) != NULL)
1039 : {
1040 : /* Yes; insert the new join node into the join tree */
1041 4760 : j->larg = *jtlink1;
1042 4760 : *jtlink1 = (Node *) j;
1043 : /* Recursively process pulled-up jointree nodes */
1044 4760 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1045 : j->rarg,
1046 : &child_rels);
1047 :
1048 : /*
1049 : * Now recursively process the pulled-up quals. Because
1050 : * we are underneath a NOT, we can't pull up sublinks that
1051 : * reference the left-hand stuff, but it's still okay to
1052 : * pull up sublinks referencing j->rarg.
1053 : */
1054 4760 : j->quals = pull_up_sublinks_qual_recurse(root,
1055 : j->quals,
1056 : &j->rarg,
1057 : child_rels,
1058 : NULL, NULL);
1059 : /* Return NULL representing constant TRUE */
1060 4760 : return NULL;
1061 : }
1062 9 : if (available_rels2 != NULL &&
1063 0 : (j = convert_EXISTS_sublink_to_join(root, sublink, true,
1064 : available_rels2)) != NULL)
1065 : {
1066 : /* Yes; insert the new join node into the join tree */
1067 0 : j->larg = *jtlink2;
1068 0 : *jtlink2 = (Node *) j;
1069 : /* Recursively process pulled-up jointree nodes */
1070 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1071 : j->rarg,
1072 : &child_rels);
1073 :
1074 : /*
1075 : * Now recursively process the pulled-up quals. Because
1076 : * we are underneath a NOT, we can't pull up sublinks that
1077 : * reference the left-hand stuff, but it's still okay to
1078 : * pull up sublinks referencing j->rarg.
1079 : */
1080 0 : j->quals = pull_up_sublinks_qual_recurse(root,
1081 : j->quals,
1082 : &j->rarg,
1083 : child_rels,
1084 : NULL, NULL);
1085 : /* Return NULL representing constant TRUE */
1086 0 : return NULL;
1087 : }
1088 : }
1089 : }
1090 : /* Else return it unmodified */
1091 7066 : return node;
1092 : }
1093 99808 : if (is_andclause(node))
1094 : {
1095 : /* Recurse into AND clause */
1096 23522 : List *newclauses = NIL;
1097 : ListCell *l;
1098 :
1099 86240 : foreach(l, ((BoolExpr *) node)->args)
1100 : {
1101 62718 : Node *oldclause = (Node *) lfirst(l);
1102 : Node *newclause;
1103 :
1104 62718 : newclause = pull_up_sublinks_qual_recurse(root,
1105 : oldclause,
1106 : jtlink1,
1107 : available_rels1,
1108 : jtlink2,
1109 : available_rels2);
1110 62718 : if (newclause)
1111 55707 : newclauses = lappend(newclauses, newclause);
1112 : }
1113 : /* We might have got back fewer clauses than we started with */
1114 23522 : if (newclauses == NIL)
1115 63 : return NULL;
1116 23459 : else if (list_length(newclauses) == 1)
1117 942 : return (Node *) linitial(newclauses);
1118 : else
1119 22517 : return (Node *) make_andclause(newclauses);
1120 : }
1121 : /* Stop if not an AND */
1122 76286 : return node;
1123 : }
1124 :
1125 : /*
1126 : * preprocess_function_rtes
1127 : * Constant-simplify any FUNCTION RTEs in the FROM clause, and then
1128 : * attempt to "inline" any that can be converted to simple subqueries.
1129 : *
1130 : * If an RTE_FUNCTION rtable entry invokes a set-returning SQL function that
1131 : * contains just a simple SELECT, we can convert the rtable entry to an
1132 : * RTE_SUBQUERY entry exposing the SELECT directly. Other sorts of functions
1133 : * are also inline-able if they have a support function that can generate
1134 : * the replacement sub-Query. This is especially useful if the subquery can
1135 : * then be "pulled up" for further optimization, but we do it even if not,
1136 : * to reduce executor overhead.
1137 : *
1138 : * This has to be done before we have started to do any optimization of
1139 : * subqueries, else any such steps wouldn't get applied to subqueries
1140 : * obtained via inlining. However, we do it after pull_up_sublinks
1141 : * so that we can inline any functions used in SubLink subselects.
1142 : *
1143 : * The reason for applying const-simplification at this stage is that
1144 : * (a) we'd need to do it anyway to inline a SRF, and (b) by doing it now,
1145 : * we can be sure that pull_up_constant_function() will see constants
1146 : * if there are constants to be seen. This approach also guarantees
1147 : * that every FUNCTION RTE has been const-simplified, allowing planner.c's
1148 : * preprocess_expression() to skip doing it again.
1149 : *
1150 : * Like most of the planner, this feels free to scribble on its input data
1151 : * structure.
1152 : */
1153 : void
1154 424845 : preprocess_function_rtes(PlannerInfo *root)
1155 : {
1156 : ListCell *rt;
1157 :
1158 1114290 : foreach(rt, root->parse->rtable)
1159 : {
1160 689449 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
1161 :
1162 689449 : if (rte->rtekind == RTE_FUNCTION)
1163 : {
1164 : Query *funcquery;
1165 :
1166 : /* Apply const-simplification */
1167 35518 : rte->functions = (List *)
1168 35518 : eval_const_expressions(root, (Node *) rte->functions);
1169 :
1170 : /* Check safety of expansion, and expand if possible */
1171 35518 : funcquery = inline_function_in_from(root, rte);
1172 35514 : if (funcquery)
1173 : {
1174 : /* Successful expansion, convert the RTE to a subquery */
1175 205 : rte->rtekind = RTE_SUBQUERY;
1176 205 : rte->subquery = funcquery;
1177 205 : rte->security_barrier = false;
1178 :
1179 : /*
1180 : * Clear fields that should not be set in a subquery RTE.
1181 : * However, we leave rte->functions filled in for the moment,
1182 : * in case makeWholeRowVar needs to consult it. We'll clear
1183 : * it in setrefs.c (see add_rte_to_flat_rtable) so that this
1184 : * abuse of the data structure doesn't escape the planner.
1185 : */
1186 205 : rte->funcordinality = false;
1187 : }
1188 : }
1189 : }
1190 424841 : }
1191 :
1192 : /*
1193 : * pull_up_subqueries
1194 : * Look for subqueries in the rangetable that can be pulled up into
1195 : * the parent query. If the subquery has no special features like
1196 : * grouping/aggregation then we can merge it into the parent's jointree.
1197 : * Also, subqueries that are simple UNION ALL structures can be
1198 : * converted into "append relations".
1199 : */
1200 : void
1201 424841 : pull_up_subqueries(PlannerInfo *root)
1202 : {
1203 : /* Top level of jointree must always be a FromExpr */
1204 : Assert(IsA(root->parse->jointree, FromExpr));
1205 : /* Recursion starts with no containing join nor appendrel */
1206 849678 : root->parse->jointree = (FromExpr *)
1207 424841 : pull_up_subqueries_recurse(root, (Node *) root->parse->jointree,
1208 : NULL, NULL);
1209 : /* We should still have a FromExpr */
1210 : Assert(IsA(root->parse->jointree, FromExpr));
1211 424837 : }
1212 :
1213 : /*
1214 : * pull_up_subqueries_recurse
1215 : * Recursive guts of pull_up_subqueries.
1216 : *
1217 : * This recursively processes the jointree and returns a modified jointree.
1218 : *
1219 : * If this jointree node is within either side of an outer join, then
1220 : * lowest_outer_join references the lowest such JoinExpr node; otherwise
1221 : * it is NULL. We use this to constrain the effects of LATERAL subqueries.
1222 : *
1223 : * If we are looking at a member subquery of an append relation,
1224 : * containing_appendrel describes that relation; else it is NULL.
1225 : * This forces use of the PlaceHolderVar mechanism for all non-Var targetlist
1226 : * items, and puts some additional restrictions on what can be pulled up.
1227 : *
1228 : * A tricky aspect of this code is that if we pull up a subquery we have
1229 : * to replace Vars that reference the subquery's outputs throughout the
1230 : * parent query, including quals attached to jointree nodes above the one
1231 : * we are currently processing! We handle this by being careful to maintain
1232 : * validity of the jointree structure while recursing, in the following sense:
1233 : * whenever we recurse, all qual expressions in the tree must be reachable
1234 : * from the top level, in case the recursive call needs to modify them.
1235 : *
1236 : * Notice also that we can't turn pullup_replace_vars loose on the whole
1237 : * jointree, because it'd return a mutated copy of the tree; we have to
1238 : * invoke it just on the quals, instead. This behavior is what makes it
1239 : * reasonable to pass lowest_outer_join as a pointer rather than some
1240 : * more-indirect way of identifying the lowest OJ. Likewise, we don't
1241 : * replace append_rel_list members but only their substructure, so the
1242 : * containing_appendrel reference is safe to use.
1243 : */
1244 : static Node *
1245 1071959 : pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
1246 : JoinExpr *lowest_outer_join,
1247 : AppendRelInfo *containing_appendrel)
1248 : {
1249 : /* Since this function recurses, it could be driven to stack overflow. */
1250 1071959 : check_stack_depth();
1251 : /* Also, since it's a bit expensive, let's check for query cancel. */
1252 1071959 : CHECK_FOR_INTERRUPTS();
1253 :
1254 : Assert(jtnode != NULL);
1255 1071959 : if (IsA(jtnode, RangeTblRef))
1256 : {
1257 553663 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1258 553663 : RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
1259 :
1260 : /*
1261 : * Is this a subquery RTE, and if so, is the subquery simple enough to
1262 : * pull up?
1263 : *
1264 : * If we are looking at an append-relation member, we can't pull it up
1265 : * unless is_safe_append_member says so.
1266 : */
1267 603943 : if (rte->rtekind == RTE_SUBQUERY &&
1268 83914 : is_simple_subquery(root, rte->subquery, rte, lowest_outer_join) &&
1269 9933 : (containing_appendrel == NULL ||
1270 9933 : is_safe_append_member(rte->subquery)))
1271 28926 : return pull_up_simple_subquery(root, jtnode, rte,
1272 : lowest_outer_join,
1273 : containing_appendrel);
1274 :
1275 : /*
1276 : * Alternatively, is it a simple UNION ALL subquery? If so, flatten
1277 : * into an "append relation".
1278 : *
1279 : * It's safe to do this regardless of whether this query is itself an
1280 : * appendrel member. (If you're thinking we should try to flatten the
1281 : * two levels of appendrel together, you're right; but we handle that
1282 : * in set_append_rel_pathlist, not here.)
1283 : */
1284 546091 : if (rte->rtekind == RTE_SUBQUERY &&
1285 21354 : is_simple_union_all(rte->subquery))
1286 4039 : return pull_up_simple_union_all(root, jtnode, rte);
1287 :
1288 : /*
1289 : * Or perhaps it's a simple VALUES RTE?
1290 : *
1291 : * We don't allow VALUES pullup below an outer join nor into an
1292 : * appendrel (such cases are impossible anyway at the moment).
1293 : */
1294 520698 : if (rte->rtekind == RTE_VALUES &&
1295 10492 : lowest_outer_join == NULL &&
1296 10492 : containing_appendrel == NULL &&
1297 10492 : is_simple_values(root, rte))
1298 3774 : return pull_up_simple_values(root, jtnode, rte);
1299 :
1300 : /*
1301 : * Or perhaps it's a FUNCTION RTE that we could inline?
1302 : */
1303 516924 : if (rte->rtekind == RTE_FUNCTION)
1304 35309 : return pull_up_constant_function(root, jtnode, rte,
1305 : containing_appendrel);
1306 :
1307 : /* Otherwise, do nothing at this node. */
1308 : }
1309 518296 : else if (IsA(jtnode, FromExpr))
1310 : {
1311 435250 : FromExpr *f = (FromExpr *) jtnode;
1312 : ListCell *l;
1313 :
1314 : Assert(containing_appendrel == NULL);
1315 : /* Recursively transform all the child nodes */
1316 903315 : foreach(l, f->fromlist)
1317 : {
1318 468069 : lfirst(l) = pull_up_subqueries_recurse(root, lfirst(l),
1319 : lowest_outer_join,
1320 : NULL);
1321 : }
1322 : }
1323 83046 : else if (IsA(jtnode, JoinExpr))
1324 : {
1325 83046 : JoinExpr *j = (JoinExpr *) jtnode;
1326 :
1327 : Assert(containing_appendrel == NULL);
1328 : /* Recurse, being careful to tell myself when inside outer join */
1329 83046 : switch (j->jointype)
1330 : {
1331 37080 : case JOIN_INNER:
1332 37080 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1333 : lowest_outer_join,
1334 : NULL);
1335 37080 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1336 : lowest_outer_join,
1337 : NULL);
1338 37080 : break;
1339 44145 : case JOIN_LEFT:
1340 : case JOIN_SEMI:
1341 : case JOIN_ANTI:
1342 44145 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1343 : j,
1344 : NULL);
1345 44145 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1346 : j,
1347 : NULL);
1348 44145 : break;
1349 858 : case JOIN_FULL:
1350 858 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1351 : j,
1352 : NULL);
1353 858 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1354 : j,
1355 : NULL);
1356 858 : break;
1357 963 : case JOIN_RIGHT:
1358 963 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1359 : j,
1360 : NULL);
1361 963 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1362 : j,
1363 : NULL);
1364 963 : break;
1365 0 : default:
1366 0 : elog(ERROR, "unrecognized join type: %d",
1367 : (int) j->jointype);
1368 : break;
1369 : }
1370 : }
1371 : else
1372 0 : elog(ERROR, "unrecognized node type: %d",
1373 : (int) nodeTag(jtnode));
1374 999907 : return jtnode;
1375 : }
1376 :
1377 : /*
1378 : * pull_up_simple_subquery
1379 : * Attempt to pull up a single simple subquery.
1380 : *
1381 : * jtnode is a RangeTblRef that has been tentatively identified as a simple
1382 : * subquery by pull_up_subqueries. We return the replacement jointree node,
1383 : * or jtnode itself if we determine that the subquery can't be pulled up
1384 : * after all.
1385 : *
1386 : * rte is the RangeTblEntry referenced by jtnode. Remaining parameters are
1387 : * as for pull_up_subqueries_recurse.
1388 : */
1389 : static Node *
1390 28926 : pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
1391 : JoinExpr *lowest_outer_join,
1392 : AppendRelInfo *containing_appendrel)
1393 : {
1394 28926 : Query *parse = root->parse;
1395 28926 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1396 : Query *subquery;
1397 : PlannerInfo *subroot;
1398 : int rtoffset;
1399 : pullup_replace_vars_context rvcontext;
1400 : ListCell *lc;
1401 :
1402 : /*
1403 : * Make a modifiable copy of the subquery to hack on, so that the RTE will
1404 : * be left unchanged in case we decide below that we can't pull it up
1405 : * after all.
1406 : */
1407 28926 : subquery = copyObject(rte->subquery);
1408 :
1409 : /*
1410 : * Create a PlannerInfo data structure for this subquery.
1411 : *
1412 : * NOTE: the next few steps should match the first processing in
1413 : * subquery_planner(). Can we refactor to avoid code duplication, or
1414 : * would that just make things uglier?
1415 : */
1416 28926 : subroot = makeNode(PlannerInfo);
1417 28926 : subroot->parse = subquery;
1418 28926 : subroot->glob = root->glob;
1419 28926 : subroot->query_level = root->query_level;
1420 28926 : subroot->plan_name = root->plan_name;
1421 28926 : subroot->parent_root = root->parent_root;
1422 28926 : subroot->plan_params = NIL;
1423 28926 : subroot->outer_params = NULL;
1424 28926 : subroot->planner_cxt = CurrentMemoryContext;
1425 28926 : subroot->init_plans = NIL;
1426 28926 : subroot->cte_plan_ids = NIL;
1427 28926 : subroot->multiexpr_params = NIL;
1428 28926 : subroot->join_domains = NIL;
1429 28926 : subroot->eq_classes = NIL;
1430 28926 : subroot->ec_merging_done = false;
1431 28926 : subroot->last_rinfo_serial = 0;
1432 28926 : subroot->all_result_relids = NULL;
1433 28926 : subroot->leaf_result_relids = NULL;
1434 28926 : subroot->append_rel_list = NIL;
1435 28926 : subroot->row_identity_vars = NIL;
1436 28926 : subroot->rowMarks = NIL;
1437 28926 : memset(subroot->upper_rels, 0, sizeof(subroot->upper_rels));
1438 28926 : memset(subroot->upper_targets, 0, sizeof(subroot->upper_targets));
1439 28926 : subroot->processed_groupClause = NIL;
1440 28926 : subroot->processed_distinctClause = NIL;
1441 28926 : subroot->processed_tlist = NIL;
1442 28926 : subroot->update_colnos = NIL;
1443 28926 : subroot->grouping_map = NULL;
1444 28926 : subroot->minmax_aggs = NIL;
1445 28926 : subroot->qual_security_level = 0;
1446 28926 : subroot->placeholdersFrozen = false;
1447 28926 : subroot->hasRecursion = false;
1448 28926 : subroot->assumeReplanning = false;
1449 28926 : subroot->wt_param_id = -1;
1450 28926 : subroot->non_recursive_path = NULL;
1451 : /* We don't currently need a top JoinDomain for the subroot */
1452 :
1453 : /* No CTEs to worry about */
1454 : Assert(subquery->cteList == NIL);
1455 :
1456 : /*
1457 : * Scan the rangetable for relation RTEs and retrieve the necessary
1458 : * catalog information for each relation. Using this information, clear
1459 : * the inh flag for any relation that has no children, collect not-null
1460 : * attribute numbers for any relation that has column not-null
1461 : * constraints, and expand virtual generated columns for any relation that
1462 : * contains them.
1463 : */
1464 28926 : subquery = subroot->parse = preprocess_relation_rtes(subroot);
1465 :
1466 : /*
1467 : * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
1468 : * that we don't need so many special cases to deal with that situation.
1469 : */
1470 28926 : replace_empty_jointree(subquery);
1471 :
1472 : /*
1473 : * Pull up any SubLinks within the subquery's quals, so that we don't
1474 : * leave unoptimized SubLinks behind.
1475 : */
1476 28926 : if (subquery->hasSubLinks)
1477 1552 : pull_up_sublinks(subroot);
1478 :
1479 : /*
1480 : * Similarly, preprocess its function RTEs to inline any set-returning
1481 : * functions in its rangetable.
1482 : */
1483 28926 : preprocess_function_rtes(subroot);
1484 :
1485 : /*
1486 : * Recursively pull up the subquery's subqueries, so that
1487 : * pull_up_subqueries' processing is complete for its jointree and
1488 : * rangetable.
1489 : *
1490 : * Note: it's okay that the subquery's recursion starts with NULL for
1491 : * containing-join info, even if we are within an outer join in the upper
1492 : * query; the lower query starts with a clean slate for outer-join
1493 : * semantics. Likewise, we needn't pass down appendrel state.
1494 : */
1495 28926 : pull_up_subqueries(subroot);
1496 :
1497 : /*
1498 : * Now we must recheck whether the subquery is still simple enough to pull
1499 : * up. If not, abandon processing it.
1500 : *
1501 : * We don't really need to recheck all the conditions involved, but it's
1502 : * easier just to keep this "if" looking the same as the one in
1503 : * pull_up_subqueries_recurse.
1504 : */
1505 34027 : if (is_simple_subquery(root, subquery, rte, lowest_outer_join) &&
1506 5225 : (containing_appendrel == NULL || is_safe_append_member(subquery)))
1507 : {
1508 : /* good to go */
1509 : }
1510 : else
1511 : {
1512 : /*
1513 : * Give up, return unmodified RangeTblRef.
1514 : *
1515 : * Note: The work we just did will be redone when the subquery gets
1516 : * planned on its own. Perhaps we could avoid that by storing the
1517 : * modified subquery back into the rangetable, but I'm not gonna risk
1518 : * it now.
1519 : */
1520 134 : return jtnode;
1521 : }
1522 :
1523 : /*
1524 : * We must flatten any join alias Vars in the subquery's targetlist,
1525 : * because pulling up the subquery's subqueries might have changed their
1526 : * expansions into arbitrary expressions, which could affect
1527 : * pullup_replace_vars' decisions about whether PlaceHolderVar wrappers
1528 : * are needed for tlist entries. (Likely it'd be better to do
1529 : * flatten_join_alias_vars on the whole query tree at some earlier stage,
1530 : * maybe even in the rewriter; but for now let's just fix this case here.)
1531 : */
1532 28792 : subquery->targetList = (List *)
1533 28792 : flatten_join_alias_vars(subroot, subroot->parse,
1534 28792 : (Node *) subquery->targetList);
1535 :
1536 : /*
1537 : * Adjust level-0 varnos in subquery so that we can append its rangetable
1538 : * to upper query's. We have to fix the subquery's append_rel_list as
1539 : * well.
1540 : */
1541 28792 : rtoffset = list_length(parse->rtable);
1542 28792 : OffsetVarNodes((Node *) subquery, rtoffset, 0);
1543 28792 : OffsetVarNodes((Node *) subroot->append_rel_list, rtoffset, 0);
1544 :
1545 : /*
1546 : * Upper-level vars in subquery are now one level closer to their parent
1547 : * than before.
1548 : */
1549 28792 : IncrementVarSublevelsUp((Node *) subquery, -1, 1);
1550 28792 : IncrementVarSublevelsUp((Node *) subroot->append_rel_list, -1, 1);
1551 :
1552 : /*
1553 : * The subquery's targetlist items are now in the appropriate form to
1554 : * insert into the top query, except that we may need to wrap them in
1555 : * PlaceHolderVars. Set up required context data for pullup_replace_vars.
1556 : * (Note that we should include the subquery's inner joins in relids,
1557 : * since it may include join alias vars referencing them.)
1558 : */
1559 28792 : rvcontext.root = root;
1560 28792 : rvcontext.targetlist = subquery->targetList;
1561 28792 : rvcontext.target_rte = rte;
1562 28792 : rvcontext.result_relation = 0;
1563 28792 : if (rte->lateral)
1564 : {
1565 1339 : rvcontext.relids = get_relids_in_jointree((Node *) subquery->jointree,
1566 : true, true);
1567 1339 : rvcontext.nullinfo = get_nullingrels(parse);
1568 : }
1569 : else /* won't need these values */
1570 : {
1571 27453 : rvcontext.relids = NULL;
1572 27453 : rvcontext.nullinfo = NULL;
1573 : }
1574 28792 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1575 28792 : rvcontext.varno = varno;
1576 : /* this flag will be set below, if needed */
1577 28792 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
1578 : /* initialize cache array with indexes 0 .. length(tlist) */
1579 28792 : rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
1580 : sizeof(Node *));
1581 :
1582 : /*
1583 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
1584 : * each expression of the subquery's targetlist items. This ensures that
1585 : * expressions retain their separate identity so that they will match
1586 : * grouping set columns when appropriate. (It'd be sufficient to wrap
1587 : * values used in grouping set columns, and do so only in non-aggregated
1588 : * portions of the tlist and havingQual, but that would require a lot of
1589 : * infrastructure that pullup_replace_vars hasn't currently got.)
1590 : */
1591 28792 : if (parse->groupingSets)
1592 336 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
1593 :
1594 : /*
1595 : * Replace all of the top query's references to the subquery's outputs
1596 : * with copies of the adjusted subtlist items, being careful not to
1597 : * replace any of the jointree structure.
1598 : */
1599 28792 : perform_pullup_replace_vars(root, &rvcontext,
1600 : containing_appendrel);
1601 :
1602 : /*
1603 : * If the subquery had a LATERAL marker, propagate that to any of its
1604 : * child RTEs that could possibly now contain lateral cross-references.
1605 : * The children might or might not contain any actual lateral
1606 : * cross-references, but we have to mark the pulled-up child RTEs so that
1607 : * later planner stages will check for such.
1608 : */
1609 28788 : if (rte->lateral)
1610 : {
1611 3545 : foreach(lc, subquery->rtable)
1612 : {
1613 2206 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(lc);
1614 :
1615 2206 : switch (child_rte->rtekind)
1616 : {
1617 1512 : case RTE_RELATION:
1618 1512 : if (child_rte->tablesample)
1619 30 : child_rte->lateral = true;
1620 1512 : break;
1621 247 : case RTE_SUBQUERY:
1622 : case RTE_FUNCTION:
1623 : case RTE_VALUES:
1624 : case RTE_TABLEFUNC:
1625 247 : child_rte->lateral = true;
1626 247 : break;
1627 447 : case RTE_JOIN:
1628 : case RTE_CTE:
1629 : case RTE_NAMEDTUPLESTORE:
1630 : case RTE_RESULT:
1631 : case RTE_GROUP:
1632 : /* these can't contain any lateral references */
1633 447 : break;
1634 0 : case RTE_GRAPH_TABLE:
1635 : /* shouldn't happen here */
1636 : Assert(false);
1637 0 : break;
1638 : }
1639 : }
1640 : }
1641 :
1642 : /*
1643 : * Now append the adjusted rtable entries and their perminfos to upper
1644 : * query. (We hold off until after fixing the upper rtable entries; no
1645 : * point in running that code on the subquery ones too.)
1646 : */
1647 28788 : CombineRangeTables(&parse->rtable, &parse->rteperminfos,
1648 : subquery->rtable, subquery->rteperminfos);
1649 :
1650 : /*
1651 : * Pull up any FOR UPDATE/SHARE markers, too. (OffsetVarNodes already
1652 : * adjusted the marker rtindexes, so just concat the lists.)
1653 : */
1654 28788 : parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
1655 :
1656 : /*
1657 : * We also have to fix the relid sets of any PlaceHolderVar nodes in the
1658 : * parent query. (This could perhaps be done by pullup_replace_vars(),
1659 : * but it seems cleaner to use two passes.) Note in particular that any
1660 : * PlaceHolderVar nodes just created by pullup_replace_vars() will be
1661 : * adjusted, so having created them with the subquery's varno is correct.
1662 : *
1663 : * Likewise, relids appearing in AppendRelInfo nodes have to be fixed. We
1664 : * already checked that this won't require introducing multiple subrelids
1665 : * into the single-slot AppendRelInfo structs.
1666 : */
1667 28788 : if (root->glob->lastPHId != 0 || root->append_rel_list)
1668 : {
1669 : Relids subrelids;
1670 :
1671 6743 : subrelids = get_relids_in_jointree((Node *) subquery->jointree,
1672 : true, false);
1673 6743 : if (root->glob->lastPHId != 0)
1674 1672 : substitute_phv_relids((Node *) parse, varno, subrelids);
1675 6743 : fix_append_rel_relids(root, varno, subrelids);
1676 : }
1677 :
1678 : /*
1679 : * And now add subquery's AppendRelInfos to our list.
1680 : */
1681 57576 : root->append_rel_list = list_concat(root->append_rel_list,
1682 28788 : subroot->append_rel_list);
1683 :
1684 : /*
1685 : * We don't have to do the equivalent bookkeeping for outer-join info,
1686 : * because that hasn't been set up yet. placeholder_list likewise.
1687 : */
1688 : Assert(root->join_info_list == NIL);
1689 : Assert(subroot->join_info_list == NIL);
1690 : Assert(root->placeholder_list == NIL);
1691 : Assert(subroot->placeholder_list == NIL);
1692 :
1693 : /*
1694 : * We no longer need the RTE's copy of the subquery's query tree. Getting
1695 : * rid of it saves nothing in particular so far as this level of query is
1696 : * concerned; but if this query level is in turn pulled up into a parent,
1697 : * we'd waste cycles copying the now-unused query tree.
1698 : */
1699 28788 : rte->subquery = NULL;
1700 :
1701 : /*
1702 : * Miscellaneous housekeeping.
1703 : *
1704 : * Although replace_rte_variables() faithfully updated parse->hasSubLinks
1705 : * if it copied any SubLinks out of the subquery's targetlist, we still
1706 : * could have SubLinks added to the query in the expressions of FUNCTION
1707 : * and VALUES RTEs copied up from the subquery. So it's necessary to copy
1708 : * subquery->hasSubLinks anyway. Perhaps this can be improved someday.
1709 : */
1710 28788 : parse->hasSubLinks |= subquery->hasSubLinks;
1711 :
1712 : /* If subquery had any RLS conditions, now main query does too */
1713 28788 : parse->hasRowSecurity |= subquery->hasRowSecurity;
1714 :
1715 : /*
1716 : * subquery won't be pulled up if it hasAggs, hasWindowFuncs, or
1717 : * hasTargetSRFs, so no work needed on those flags
1718 : */
1719 :
1720 : /*
1721 : * Return the adjusted subquery jointree to replace the RangeTblRef entry
1722 : * in parent's jointree; or, if the FromExpr is degenerate, just return
1723 : * its single member.
1724 : */
1725 : Assert(IsA(subquery->jointree, FromExpr));
1726 : Assert(subquery->jointree->fromlist != NIL);
1727 53188 : if (subquery->jointree->quals == NULL &&
1728 24400 : list_length(subquery->jointree->fromlist) == 1)
1729 24146 : return (Node *) linitial(subquery->jointree->fromlist);
1730 :
1731 4642 : return (Node *) subquery->jointree;
1732 : }
1733 :
1734 : /*
1735 : * pull_up_simple_union_all
1736 : * Pull up a single simple UNION ALL subquery.
1737 : *
1738 : * jtnode is a RangeTblRef that has been identified as a simple UNION ALL
1739 : * subquery by pull_up_subqueries. We pull up the leaf subqueries and
1740 : * build an "append relation" for the union set. The result value is just
1741 : * jtnode, since we don't actually need to change the query jointree.
1742 : */
1743 : static Node *
1744 4039 : pull_up_simple_union_all(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1745 : {
1746 4039 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1747 4039 : Query *subquery = rte->subquery;
1748 4039 : int rtoffset = list_length(root->parse->rtable);
1749 : List *rtable;
1750 :
1751 : /*
1752 : * Make a modifiable copy of the subquery's rtable, so we can adjust
1753 : * upper-level Vars in it. There are no such Vars in the setOperations
1754 : * tree proper, so fixing the rtable should be sufficient.
1755 : */
1756 4039 : rtable = copyObject(subquery->rtable);
1757 :
1758 : /*
1759 : * Upper-level vars in subquery are now one level closer to their parent
1760 : * than before. We don't have to worry about offsetting varnos, though,
1761 : * because the UNION leaf queries can't cross-reference each other.
1762 : */
1763 4039 : IncrementVarSublevelsUp_rtable(rtable, -1, 1);
1764 :
1765 : /*
1766 : * If the UNION ALL subquery had a LATERAL marker, propagate that to all
1767 : * its children. The individual children might or might not contain any
1768 : * actual lateral cross-references, but we have to mark the pulled-up
1769 : * child RTEs so that later planner stages will check for such.
1770 : */
1771 4039 : if (rte->lateral)
1772 : {
1773 : ListCell *rt;
1774 :
1775 1048 : foreach(rt, rtable)
1776 : {
1777 817 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(rt);
1778 :
1779 : Assert(child_rte->rtekind == RTE_SUBQUERY);
1780 817 : child_rte->lateral = true;
1781 : }
1782 : }
1783 :
1784 : /*
1785 : * Append child RTEs (and their perminfos) to parent rtable.
1786 : */
1787 4039 : CombineRangeTables(&root->parse->rtable, &root->parse->rteperminfos,
1788 : rtable, subquery->rteperminfos);
1789 :
1790 : /*
1791 : * Recursively scan the subquery's setOperations tree and add
1792 : * AppendRelInfo nodes for leaf subqueries to the parent's
1793 : * append_rel_list. Also apply pull_up_subqueries to the leaf subqueries.
1794 : */
1795 : Assert(subquery->setOperations);
1796 4039 : pull_up_union_leaf_queries(subquery->setOperations, root, varno, subquery,
1797 : rtoffset);
1798 :
1799 : /*
1800 : * Mark the parent as an append relation.
1801 : */
1802 4039 : rte->inh = true;
1803 :
1804 4039 : return jtnode;
1805 : }
1806 :
1807 : /*
1808 : * pull_up_union_leaf_queries -- recursive guts of pull_up_simple_union_all
1809 : *
1810 : * Build an AppendRelInfo for each leaf query in the setop tree, and then
1811 : * apply pull_up_subqueries to the leaf query.
1812 : *
1813 : * Note that setOpQuery is the Query containing the setOp node, whose tlist
1814 : * contains references to all the setop output columns. When called from
1815 : * pull_up_simple_union_all, this is *not* the same as root->parse, which is
1816 : * the parent Query we are pulling up into.
1817 : *
1818 : * parentRTindex is the appendrel parent's index in root->parse->rtable.
1819 : *
1820 : * The child RTEs have already been copied to the parent. childRToffset
1821 : * tells us where in the parent's range table they were copied. When called
1822 : * from flatten_simple_union_all, childRToffset is 0 since the child RTEs
1823 : * were already in root->parse->rtable and no RT index adjustment is needed.
1824 : */
1825 : static void
1826 21332 : pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
1827 : Query *setOpQuery, int childRToffset)
1828 : {
1829 21332 : if (IsA(setOp, RangeTblRef))
1830 : {
1831 12957 : RangeTblRef *rtr = (RangeTblRef *) setOp;
1832 : int childRTindex;
1833 : AppendRelInfo *appinfo;
1834 :
1835 : /*
1836 : * Calculate the index in the parent's range table
1837 : */
1838 12957 : childRTindex = childRToffset + rtr->rtindex;
1839 :
1840 : /*
1841 : * Build a suitable AppendRelInfo, and attach to parent's list.
1842 : */
1843 12957 : appinfo = makeNode(AppendRelInfo);
1844 12957 : appinfo->parent_relid = parentRTindex;
1845 12957 : appinfo->child_relid = childRTindex;
1846 12957 : appinfo->parent_reltype = InvalidOid;
1847 12957 : appinfo->child_reltype = InvalidOid;
1848 12957 : make_setop_translation_list(setOpQuery, childRTindex, appinfo);
1849 12957 : appinfo->parent_reloid = InvalidOid;
1850 12957 : root->append_rel_list = lappend(root->append_rel_list, appinfo);
1851 :
1852 : /*
1853 : * Recursively apply pull_up_subqueries to the new child RTE. (We
1854 : * must build the AppendRelInfo first, because this will modify it;
1855 : * indeed, that's the only part of the upper query where Vars
1856 : * referencing childRTindex can exist at this point.)
1857 : *
1858 : * Note that we can pass NULL for containing-join info even if we're
1859 : * actually under an outer join, because the child's expressions
1860 : * aren't going to propagate up to the join. Also, we ignore the
1861 : * possibility that pull_up_subqueries_recurse() returns a different
1862 : * jointree node than what we pass it; if it does, the important thing
1863 : * is that it replaced the child relid in the AppendRelInfo node.
1864 : */
1865 12957 : rtr = makeNode(RangeTblRef);
1866 12957 : rtr->rtindex = childRTindex;
1867 12957 : (void) pull_up_subqueries_recurse(root, (Node *) rtr,
1868 : NULL, appinfo);
1869 : }
1870 8375 : else if (IsA(setOp, SetOperationStmt))
1871 : {
1872 8375 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1873 :
1874 : /* Recurse to reach leaf queries */
1875 8375 : pull_up_union_leaf_queries(op->larg, root, parentRTindex, setOpQuery,
1876 : childRToffset);
1877 8375 : pull_up_union_leaf_queries(op->rarg, root, parentRTindex, setOpQuery,
1878 : childRToffset);
1879 : }
1880 : else
1881 : {
1882 0 : elog(ERROR, "unrecognized node type: %d",
1883 : (int) nodeTag(setOp));
1884 : }
1885 21332 : }
1886 :
1887 : /*
1888 : * make_setop_translation_list
1889 : * Build the list of translations from parent Vars to child Vars for
1890 : * a UNION ALL member. (At this point it's just a simple list of
1891 : * referencing Vars, but if we succeed in pulling up the member
1892 : * subquery, the Vars will get replaced by pulled-up expressions.)
1893 : * Also create the rather trivial reverse-translation array.
1894 : */
1895 : static void
1896 12957 : make_setop_translation_list(Query *query, int newvarno,
1897 : AppendRelInfo *appinfo)
1898 : {
1899 12957 : List *vars = NIL;
1900 : AttrNumber *pcolnos;
1901 : ListCell *l;
1902 :
1903 : /* Initialize reverse-translation array with all entries zero */
1904 : /* (entries for resjunk columns will stay that way) */
1905 12957 : appinfo->num_child_cols = list_length(query->targetList);
1906 12957 : appinfo->parent_colnos = pcolnos =
1907 12957 : (AttrNumber *) palloc0(appinfo->num_child_cols * sizeof(AttrNumber));
1908 :
1909 56060 : foreach(l, query->targetList)
1910 : {
1911 43103 : TargetEntry *tle = (TargetEntry *) lfirst(l);
1912 :
1913 43103 : if (tle->resjunk)
1914 0 : continue;
1915 :
1916 43103 : vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
1917 43103 : pcolnos[tle->resno - 1] = tle->resno;
1918 : }
1919 :
1920 12957 : appinfo->translated_vars = vars;
1921 12957 : }
1922 :
1923 : /*
1924 : * is_simple_subquery
1925 : * Check a subquery in the range table to see if it's simple enough
1926 : * to pull up into the parent query.
1927 : *
1928 : * rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
1929 : * (Note subquery is not necessarily equal to rte->subquery; it could be a
1930 : * processed copy of that.)
1931 : * lowest_outer_join is the lowest outer join above the subquery, or NULL.
1932 : */
1933 : static bool
1934 79206 : is_simple_subquery(PlannerInfo *root, Query *subquery, RangeTblEntry *rte,
1935 : JoinExpr *lowest_outer_join)
1936 : {
1937 : /*
1938 : * Let's just make sure it's a valid subselect ...
1939 : */
1940 79206 : if (!IsA(subquery, Query) ||
1941 79206 : subquery->commandType != CMD_SELECT)
1942 0 : elog(ERROR, "subquery is bogus");
1943 :
1944 : /*
1945 : * Can't currently pull up a query with setops (unless it's simple UNION
1946 : * ALL, which is handled by a different code path). Maybe after querytree
1947 : * redesign...
1948 : */
1949 79206 : if (subquery->setOperations)
1950 4629 : return false;
1951 :
1952 : /*
1953 : * Can't pull up a subquery involving grouping, aggregation, SRFs,
1954 : * sorting, limiting, or WITH. (XXX WITH could possibly be allowed later)
1955 : *
1956 : * We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
1957 : * clauses, because pullup would cause the locking to occur semantically
1958 : * higher than it should. Implicit FOR UPDATE/SHARE is okay because in
1959 : * that case the locking was originally declared in the upper query
1960 : * anyway.
1961 : */
1962 74577 : if (subquery->hasAggs ||
1963 73080 : subquery->hasWindowFuncs ||
1964 72759 : subquery->hasTargetSRFs ||
1965 69154 : subquery->groupClause ||
1966 69080 : subquery->groupingSets ||
1967 69050 : subquery->havingQual ||
1968 69050 : subquery->sortClause ||
1969 68353 : subquery->distinctClause ||
1970 67808 : subquery->limitOffset ||
1971 67423 : subquery->limitCount ||
1972 67146 : subquery->hasForUpdate ||
1973 63902 : subquery->cteList)
1974 10820 : return false;
1975 :
1976 : /*
1977 : * Don't pull up if the RTE represents a security-barrier view; we
1978 : * couldn't prevent information leakage once the RTE's Vars are scattered
1979 : * about in the upper query.
1980 : */
1981 63757 : if (rte->security_barrier)
1982 963 : return false;
1983 :
1984 : /*
1985 : * If the subquery is LATERAL, check for pullup restrictions from that.
1986 : */
1987 62794 : if (rte->lateral)
1988 : {
1989 : bool restricted;
1990 : Relids safe_upper_varnos;
1991 :
1992 : /*
1993 : * The subquery's WHERE and JOIN/ON quals mustn't contain any lateral
1994 : * references to rels outside a higher outer join (including the case
1995 : * where the outer join is within the subquery itself). In such a
1996 : * case, pulling up would result in a situation where we need to
1997 : * postpone quals from below an outer join to above it, which is
1998 : * probably completely wrong and in any case is a complication that
1999 : * doesn't seem worth addressing at the moment.
2000 : */
2001 3390 : if (lowest_outer_join != NULL)
2002 : {
2003 1020 : restricted = true;
2004 1020 : safe_upper_varnos = get_relids_in_jointree((Node *) lowest_outer_join,
2005 : true, true);
2006 : }
2007 : else
2008 : {
2009 2370 : restricted = false;
2010 2370 : safe_upper_varnos = NULL; /* doesn't matter */
2011 : }
2012 :
2013 3390 : if (jointree_contains_lateral_outer_refs(root,
2014 3390 : (Node *) subquery->jointree,
2015 : restricted, safe_upper_varnos))
2016 20 : return false;
2017 :
2018 : /*
2019 : * If there's an outer join above the LATERAL subquery, also disallow
2020 : * pullup if the subquery's targetlist has any references to rels
2021 : * outside the outer join, since these might get pulled into quals
2022 : * above the subquery (but in or below the outer join) and then lead
2023 : * to qual-postponement issues similar to the case checked for above.
2024 : * (We wouldn't need to prevent pullup if no such references appear in
2025 : * outer-query quals, but we don't have enough info here to check
2026 : * that. Also, maybe this restriction could be removed if we forced
2027 : * such refs to be wrapped in PlaceHolderVars, even when they're below
2028 : * the nearest outer join? But it's a pretty hokey usage, so not
2029 : * clear this is worth sweating over.)
2030 : *
2031 : * If you change this, see also the comments about lateral references
2032 : * in pullup_replace_vars_callback().
2033 : */
2034 3370 : if (lowest_outer_join != NULL)
2035 : {
2036 1020 : Relids lvarnos = pull_varnos_of_level(root,
2037 1020 : (Node *) subquery->targetList,
2038 : 1);
2039 :
2040 1020 : if (!bms_is_subset(lvarnos, safe_upper_varnos))
2041 10 : return false;
2042 : }
2043 : }
2044 :
2045 : /*
2046 : * Don't pull up a subquery that has any volatile functions in its
2047 : * targetlist. Otherwise we might introduce multiple evaluations of these
2048 : * functions, if they get copied to multiple places in the upper query,
2049 : * leading to surprising results. (Note: the PlaceHolderVar mechanism
2050 : * doesn't quite guarantee single evaluation; else we could pull up anyway
2051 : * and just wrap such items in PlaceHolderVars ...)
2052 : */
2053 62764 : if (contain_volatile_functions((Node *) subquery->targetList))
2054 214 : return false;
2055 :
2056 62550 : return true;
2057 : }
2058 :
2059 : /*
2060 : * pull_up_simple_values
2061 : * Pull up a single simple VALUES RTE.
2062 : *
2063 : * jtnode is a RangeTblRef that has been identified as a simple VALUES RTE
2064 : * by pull_up_subqueries. We always return a RangeTblRef representing a
2065 : * RESULT RTE to replace it (all failure cases should have been detected by
2066 : * is_simple_values()). Actually, what we return is just jtnode, because
2067 : * we replace the VALUES RTE in the rangetable with the RESULT RTE.
2068 : *
2069 : * rte is the RangeTblEntry referenced by jtnode. Because of the limited
2070 : * possible usage of VALUES RTEs, we do not need the remaining parameters
2071 : * of pull_up_subqueries_recurse.
2072 : */
2073 : static Node *
2074 3774 : pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
2075 : {
2076 3774 : Query *parse = root->parse;
2077 3774 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2078 : List *values_list;
2079 : List *tlist;
2080 : AttrNumber attrno;
2081 : pullup_replace_vars_context rvcontext;
2082 : ListCell *lc;
2083 :
2084 : Assert(rte->rtekind == RTE_VALUES);
2085 : Assert(list_length(rte->values_lists) == 1);
2086 :
2087 : /*
2088 : * Need a modifiable copy of the VALUES list to hack on, just in case it's
2089 : * multiply referenced.
2090 : */
2091 3774 : values_list = copyObject(linitial(rte->values_lists));
2092 :
2093 : /*
2094 : * The VALUES RTE can't contain any Vars of level zero, let alone any that
2095 : * are join aliases, so no need to flatten join alias Vars.
2096 : */
2097 : Assert(!contain_vars_of_level((Node *) values_list, 0));
2098 :
2099 : /*
2100 : * Set up required context data for pullup_replace_vars. In particular,
2101 : * we have to make the VALUES list look like a subquery targetlist.
2102 : */
2103 3774 : tlist = NIL;
2104 3774 : attrno = 1;
2105 8067 : foreach(lc, values_list)
2106 : {
2107 4293 : tlist = lappend(tlist,
2108 4293 : makeTargetEntry((Expr *) lfirst(lc),
2109 : attrno,
2110 : NULL,
2111 : false));
2112 4293 : attrno++;
2113 : }
2114 3774 : rvcontext.root = root;
2115 3774 : rvcontext.targetlist = tlist;
2116 3774 : rvcontext.target_rte = rte;
2117 3774 : rvcontext.result_relation = 0;
2118 3774 : rvcontext.relids = NULL; /* can't be any lateral references here */
2119 3774 : rvcontext.nullinfo = NULL;
2120 3774 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2121 3774 : rvcontext.varno = varno;
2122 3774 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2123 : /* initialize cache array with indexes 0 .. length(tlist) */
2124 3774 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
2125 : sizeof(Node *));
2126 :
2127 : /*
2128 : * Replace all of the top query's references to the RTE's outputs with
2129 : * copies of the adjusted VALUES expressions, being careful not to replace
2130 : * any of the jointree structure. We can assume there's no outer joins or
2131 : * appendrels in the dummy Query that surrounds a VALUES RTE.
2132 : */
2133 3774 : perform_pullup_replace_vars(root, &rvcontext, NULL);
2134 :
2135 : /*
2136 : * There should be no appendrels to fix, nor any outer joins and hence no
2137 : * PlaceHolderVars.
2138 : */
2139 : Assert(root->append_rel_list == NIL);
2140 : Assert(root->join_info_list == NIL);
2141 : Assert(root->placeholder_list == NIL);
2142 :
2143 : /*
2144 : * Replace the VALUES RTE with a RESULT RTE. The VALUES RTE is the only
2145 : * rtable entry in the current query level, so this is easy.
2146 : */
2147 : Assert(list_length(parse->rtable) == 1);
2148 :
2149 : /* Create suitable RTE */
2150 3774 : rte = makeNode(RangeTblEntry);
2151 3774 : rte->rtekind = RTE_RESULT;
2152 3774 : rte->eref = makeAlias("*RESULT*", NIL);
2153 :
2154 : /* Replace rangetable */
2155 3774 : parse->rtable = list_make1(rte);
2156 :
2157 : /* We could manufacture a new RangeTblRef, but the one we have is fine */
2158 : Assert(varno == 1);
2159 :
2160 3774 : return jtnode;
2161 : }
2162 :
2163 : /*
2164 : * is_simple_values
2165 : * Check a VALUES RTE in the range table to see if it's simple enough
2166 : * to pull up into the parent query.
2167 : *
2168 : * rte is the RTE_VALUES RangeTblEntry to check.
2169 : */
2170 : static bool
2171 10492 : is_simple_values(PlannerInfo *root, RangeTblEntry *rte)
2172 : {
2173 : Assert(rte->rtekind == RTE_VALUES);
2174 :
2175 : /*
2176 : * There must be exactly one VALUES list, else it's not semantically
2177 : * correct to replace the VALUES RTE with a RESULT RTE, nor would we have
2178 : * a unique set of expressions to substitute into the parent query.
2179 : */
2180 10492 : if (list_length(rte->values_lists) != 1)
2181 6718 : return false;
2182 :
2183 : /*
2184 : * Because VALUES can't appear under an outer join (or at least, we won't
2185 : * try to pull it up if it does), we need not worry about LATERAL, nor
2186 : * about validity of PHVs for the VALUES' outputs.
2187 : */
2188 :
2189 : /*
2190 : * Don't pull up a VALUES that contains any set-returning or volatile
2191 : * functions. The considerations here are basically identical to the
2192 : * restrictions on a pull-able subquery's targetlist.
2193 : */
2194 7548 : if (expression_returns_set((Node *) rte->values_lists) ||
2195 3774 : contain_volatile_functions((Node *) rte->values_lists))
2196 0 : return false;
2197 :
2198 : /*
2199 : * Do not pull up a VALUES that's not the only RTE in its parent query.
2200 : * This is actually the only case that the parser will generate at the
2201 : * moment, and assuming this is true greatly simplifies
2202 : * pull_up_simple_values().
2203 : */
2204 3774 : if (list_length(root->parse->rtable) != 1 ||
2205 3774 : rte != (RangeTblEntry *) linitial(root->parse->rtable))
2206 0 : return false;
2207 :
2208 3774 : return true;
2209 : }
2210 :
2211 : /*
2212 : * pull_up_constant_function
2213 : * Pull up an RTE_FUNCTION expression that was simplified to a constant.
2214 : *
2215 : * jtnode is a RangeTblRef that has been identified as a FUNCTION RTE by
2216 : * pull_up_subqueries. If its expression is just a Const, hoist that value
2217 : * up into the parent query, and replace the RTE_FUNCTION with RTE_RESULT.
2218 : *
2219 : * In principle we could pull up any immutable expression, but we don't.
2220 : * That might result in multiple evaluations of the expression, which could
2221 : * be costly if it's not just a Const. Also, the main value of this is
2222 : * to let the constant participate in further const-folding, and of course
2223 : * that won't happen for a non-Const.
2224 : *
2225 : * The pulled-up value might need to be wrapped in a PlaceHolderVar if the
2226 : * RTE is below an outer join or is part of an appendrel; the extra
2227 : * parameters show whether that's needed.
2228 : */
2229 : static Node *
2230 35309 : pull_up_constant_function(PlannerInfo *root, Node *jtnode,
2231 : RangeTblEntry *rte,
2232 : AppendRelInfo *containing_appendrel)
2233 : {
2234 35309 : Query *parse = root->parse;
2235 : RangeTblFunction *rtf;
2236 : TypeFuncClass functypclass;
2237 : Oid funcrettype;
2238 : TupleDesc tupdesc;
2239 : pullup_replace_vars_context rvcontext;
2240 :
2241 : /* Fail if the RTE has ORDINALITY - we don't implement that here. */
2242 35309 : if (rte->funcordinality)
2243 759 : return jtnode;
2244 :
2245 : /* Fail if RTE isn't a single, simple Const expr */
2246 34550 : if (list_length(rte->functions) != 1)
2247 57 : return jtnode;
2248 34493 : rtf = linitial_node(RangeTblFunction, rte->functions);
2249 34493 : if (!IsA(rtf->funcexpr, Const))
2250 34183 : return jtnode;
2251 :
2252 : /*
2253 : * If the function's result is not a scalar, we punt. In principle we
2254 : * could break the composite constant value apart into per-column
2255 : * constants, but for now it seems not worth the work.
2256 : */
2257 310 : if (rtf->funccolcount != 1)
2258 25 : return jtnode; /* definitely composite */
2259 :
2260 : /* If it has a coldeflist, it certainly returns RECORD */
2261 285 : if (rtf->funccolnames != NIL)
2262 0 : return jtnode; /* must be a one-column RECORD type */
2263 :
2264 285 : functypclass = get_expr_result_type(rtf->funcexpr,
2265 : &funcrettype,
2266 : &tupdesc);
2267 285 : if (functypclass != TYPEFUNC_SCALAR)
2268 10 : return jtnode; /* must be a one-column composite type */
2269 :
2270 : /* Create context for applying pullup_replace_vars */
2271 275 : rvcontext.root = root;
2272 275 : rvcontext.targetlist = list_make1(makeTargetEntry((Expr *) rtf->funcexpr,
2273 : 1, /* resno */
2274 : NULL, /* resname */
2275 : false)); /* resjunk */
2276 275 : rvcontext.target_rte = rte;
2277 275 : rvcontext.result_relation = 0;
2278 :
2279 : /*
2280 : * Since this function was reduced to a Const, it doesn't contain any
2281 : * lateral references, even if it's marked as LATERAL. This means we
2282 : * don't need to fill relids or nullinfo.
2283 : */
2284 275 : rvcontext.relids = NULL;
2285 275 : rvcontext.nullinfo = NULL;
2286 :
2287 275 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2288 275 : rvcontext.varno = ((RangeTblRef *) jtnode)->rtindex;
2289 : /* this flag will be set below, if needed */
2290 275 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2291 : /* initialize cache array with indexes 0 .. length(tlist) */
2292 275 : rvcontext.rv_cache = palloc0((list_length(rvcontext.targetlist) + 1) *
2293 : sizeof(Node *));
2294 :
2295 : /*
2296 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
2297 : * each expression of the subquery's targetlist items. (See comments in
2298 : * pull_up_simple_subquery().)
2299 : */
2300 275 : if (parse->groupingSets)
2301 0 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
2302 :
2303 : /*
2304 : * Replace all of the top query's references to the RTE's output with
2305 : * copies of the funcexpr, being careful not to replace any of the
2306 : * jointree structure.
2307 : */
2308 275 : perform_pullup_replace_vars(root, &rvcontext,
2309 : containing_appendrel);
2310 :
2311 : /*
2312 : * We don't need to bother with changing PlaceHolderVars in the parent
2313 : * query. Their references to the RT index are still good for now, and
2314 : * will get removed later if we're able to drop the RTE_RESULT.
2315 : */
2316 :
2317 : /*
2318 : * Convert the RTE to be RTE_RESULT type, signifying that we don't need to
2319 : * scan it anymore, and zero out RTE_FUNCTION-specific fields. Also make
2320 : * sure the RTE is not marked LATERAL, since elsewhere we don't expect
2321 : * RTE_RESULTs to be LATERAL.
2322 : */
2323 275 : rte->rtekind = RTE_RESULT;
2324 275 : rte->functions = NIL;
2325 275 : rte->lateral = false;
2326 :
2327 : /*
2328 : * We can reuse the RangeTblRef node.
2329 : */
2330 275 : return jtnode;
2331 : }
2332 :
2333 : /*
2334 : * is_simple_union_all
2335 : * Check a subquery to see if it's a simple UNION ALL.
2336 : *
2337 : * We require all the setops to be UNION ALL (no mixing) and there can't be
2338 : * any datatype coercions involved, ie, all the leaf queries must emit the
2339 : * same datatypes.
2340 : */
2341 : static bool
2342 21354 : is_simple_union_all(Query *subquery)
2343 : {
2344 : SetOperationStmt *topop;
2345 :
2346 : /* Let's just make sure it's a valid subselect ... */
2347 21354 : if (!IsA(subquery, Query) ||
2348 21354 : subquery->commandType != CMD_SELECT)
2349 0 : elog(ERROR, "subquery is bogus");
2350 :
2351 : /* Is it a set-operation query at all? */
2352 21354 : topop = castNode(SetOperationStmt, subquery->setOperations);
2353 21354 : if (!topop)
2354 16725 : return false;
2355 :
2356 : /* Can't handle ORDER BY, LIMIT/OFFSET, locking, or WITH */
2357 4629 : if (subquery->sortClause ||
2358 4577 : subquery->limitOffset ||
2359 4577 : subquery->limitCount ||
2360 4577 : subquery->rowMarks ||
2361 4577 : subquery->cteList)
2362 158 : return false;
2363 :
2364 : /* Recursively check the tree of set operations */
2365 4471 : return is_simple_union_all_recurse((Node *) topop, subquery,
2366 : topop->colTypes);
2367 : }
2368 :
2369 : static bool
2370 27439 : is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes)
2371 : {
2372 : /* Since this function recurses, it could be driven to stack overflow. */
2373 27439 : check_stack_depth();
2374 :
2375 27439 : if (IsA(setOp, RangeTblRef))
2376 : {
2377 13815 : RangeTblRef *rtr = (RangeTblRef *) setOp;
2378 13815 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
2379 13815 : Query *subquery = rte->subquery;
2380 :
2381 : Assert(subquery != NULL);
2382 :
2383 : /* Leaf nodes are OK if they match the toplevel column types */
2384 : /* We don't have to compare typmods or collations here */
2385 13815 : return tlist_same_datatypes(subquery->targetList, colTypes, true);
2386 : }
2387 13624 : else if (IsA(setOp, SetOperationStmt))
2388 : {
2389 13624 : SetOperationStmt *op = (SetOperationStmt *) setOp;
2390 :
2391 : /* Must be UNION ALL */
2392 13624 : if (op->op != SETOP_UNION || !op->all)
2393 4155 : return false;
2394 :
2395 : /* Recurse to check inputs */
2396 18204 : return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
2397 8735 : is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
2398 : }
2399 : else
2400 : {
2401 0 : elog(ERROR, "unrecognized node type: %d",
2402 : (int) nodeTag(setOp));
2403 : return false; /* keep compiler quiet */
2404 : }
2405 : }
2406 :
2407 : /*
2408 : * is_safe_append_member
2409 : * Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
2410 : * safe to pull up.
2411 : */
2412 : static bool
2413 15158 : is_safe_append_member(Query *subquery)
2414 : {
2415 : FromExpr *jtnode;
2416 :
2417 : /*
2418 : * It's only safe to pull up the child if its jointree contains exactly
2419 : * one RTE, else the AppendRelInfo data structure breaks. The one base RTE
2420 : * could be buried in several levels of FromExpr, however. Also, if the
2421 : * child's jointree is completely empty, we can pull up because
2422 : * pull_up_simple_subquery will insert a single RTE_RESULT RTE instead.
2423 : *
2424 : * Also, the child can't have any WHERE quals because there's no place to
2425 : * put them in an appendrel. (This is a bit annoying...) If we didn't
2426 : * need to check this, we'd just test whether get_relids_in_jointree()
2427 : * yields a singleton set, to be more consistent with the coding of
2428 : * fix_append_rel_relids().
2429 : */
2430 15158 : jtnode = subquery->jointree;
2431 : Assert(IsA(jtnode, FromExpr));
2432 : /* Check the completely-empty case */
2433 15158 : if (jtnode->fromlist == NIL && jtnode->quals == NULL)
2434 554 : return true;
2435 : /* Check the more general case */
2436 25571 : while (IsA(jtnode, FromExpr))
2437 : {
2438 14614 : if (jtnode->quals != NULL)
2439 3647 : return false;
2440 10967 : if (list_length(jtnode->fromlist) != 1)
2441 0 : return false;
2442 10967 : jtnode = linitial(jtnode->fromlist);
2443 : }
2444 10957 : if (!IsA(jtnode, RangeTblRef))
2445 1185 : return false;
2446 :
2447 9772 : return true;
2448 : }
2449 :
2450 : /*
2451 : * jointree_contains_lateral_outer_refs
2452 : * Check for disallowed lateral references in a jointree's quals
2453 : *
2454 : * If restricted is false, all level-1 Vars are allowed (but we still must
2455 : * search the jointree, since it might contain outer joins below which there
2456 : * will be restrictions). If restricted is true, return true when any qual
2457 : * in the jointree contains level-1 Vars coming from outside the rels listed
2458 : * in safe_upper_varnos.
2459 : */
2460 : static bool
2461 9960 : jointree_contains_lateral_outer_refs(PlannerInfo *root, Node *jtnode,
2462 : bool restricted,
2463 : Relids safe_upper_varnos)
2464 : {
2465 9960 : if (jtnode == NULL)
2466 0 : return false;
2467 9960 : if (IsA(jtnode, RangeTblRef))
2468 6271 : return false;
2469 3689 : else if (IsA(jtnode, FromExpr))
2470 : {
2471 3430 : FromExpr *f = (FromExpr *) jtnode;
2472 : ListCell *l;
2473 :
2474 : /* First, recurse to check child joins */
2475 9462 : foreach(l, f->fromlist)
2476 : {
2477 6052 : if (jointree_contains_lateral_outer_refs(root,
2478 6052 : lfirst(l),
2479 : restricted,
2480 : safe_upper_varnos))
2481 20 : return true;
2482 : }
2483 :
2484 : /* Then check the top-level quals */
2485 3410 : if (restricted &&
2486 1060 : !bms_is_subset(pull_varnos_of_level(root, f->quals, 1),
2487 : safe_upper_varnos))
2488 0 : return true;
2489 : }
2490 259 : else if (IsA(jtnode, JoinExpr))
2491 : {
2492 259 : JoinExpr *j = (JoinExpr *) jtnode;
2493 :
2494 : /*
2495 : * If this is an outer join, we mustn't allow any upper lateral
2496 : * references in or below it.
2497 : */
2498 259 : if (j->jointype != JOIN_INNER)
2499 : {
2500 129 : restricted = true;
2501 129 : safe_upper_varnos = NULL;
2502 : }
2503 :
2504 : /* Check the child joins */
2505 259 : if (jointree_contains_lateral_outer_refs(root,
2506 : j->larg,
2507 : restricted,
2508 : safe_upper_varnos))
2509 0 : return true;
2510 259 : if (jointree_contains_lateral_outer_refs(root,
2511 : j->rarg,
2512 : restricted,
2513 : safe_upper_varnos))
2514 0 : return true;
2515 :
2516 : /* Check the JOIN's qual clauses */
2517 259 : if (restricted &&
2518 239 : !bms_is_subset(pull_varnos_of_level(root, j->quals, 1),
2519 : safe_upper_varnos))
2520 20 : return true;
2521 : }
2522 : else
2523 0 : elog(ERROR, "unrecognized node type: %d",
2524 : (int) nodeTag(jtnode));
2525 3649 : return false;
2526 : }
2527 :
2528 : /*
2529 : * Perform pullup_replace_vars everyplace it's needed in the query tree.
2530 : *
2531 : * Caller has already filled *rvcontext with data describing what to
2532 : * substitute for Vars referencing the target subquery. In addition
2533 : * we need the identity of the containing appendrel if any.
2534 : */
2535 : static void
2536 32841 : perform_pullup_replace_vars(PlannerInfo *root,
2537 : pullup_replace_vars_context *rvcontext,
2538 : AppendRelInfo *containing_appendrel)
2539 : {
2540 32841 : Query *parse = root->parse;
2541 : ListCell *lc;
2542 :
2543 : /*
2544 : * If we are considering an appendrel child subquery (that is, a UNION ALL
2545 : * member query that we're pulling up), then the only part of the upper
2546 : * query that could reference the child yet is the translated_vars list of
2547 : * the associated AppendRelInfo. Furthermore, we do not want to force use
2548 : * of PHVs in the AppendRelInfo --- there isn't any outer join between.
2549 : */
2550 32841 : if (containing_appendrel)
2551 : {
2552 5101 : ReplaceWrapOption save_wrap_option = rvcontext->wrap_option;
2553 :
2554 5101 : rvcontext->wrap_option = REPLACE_WRAP_NONE;
2555 5101 : containing_appendrel->translated_vars = (List *)
2556 5101 : pullup_replace_vars((Node *) containing_appendrel->translated_vars,
2557 : rvcontext);
2558 5101 : rvcontext->wrap_option = save_wrap_option;
2559 5101 : return;
2560 : }
2561 :
2562 : /*
2563 : * Replace all of the top query's references to the subquery's outputs
2564 : * with copies of the adjusted subtlist items, being careful not to
2565 : * replace any of the jointree structure. (This'd be a lot cleaner if we
2566 : * could use query_tree_mutator.) We have to use PHVs in the targetList,
2567 : * returningList, and havingQual, since those are certainly above any
2568 : * outer join. replace_vars_in_jointree tracks its location in the
2569 : * jointree and uses PHVs or not appropriately.
2570 : */
2571 27740 : parse->targetList = (List *)
2572 27740 : pullup_replace_vars((Node *) parse->targetList, rvcontext);
2573 27740 : parse->returningList = (List *)
2574 27740 : pullup_replace_vars((Node *) parse->returningList, rvcontext);
2575 :
2576 27740 : if (parse->onConflict)
2577 : {
2578 34 : parse->onConflict->onConflictSet = (List *)
2579 17 : pullup_replace_vars((Node *) parse->onConflict->onConflictSet,
2580 : rvcontext);
2581 17 : parse->onConflict->onConflictWhere =
2582 17 : pullup_replace_vars(parse->onConflict->onConflictWhere,
2583 : rvcontext);
2584 :
2585 : /*
2586 : * We assume ON CONFLICT's arbiterElems, arbiterWhere, exclRelTlist
2587 : * can't contain any references to a subquery.
2588 : */
2589 : }
2590 27740 : if (parse->mergeActionList)
2591 : {
2592 2333 : foreach(lc, parse->mergeActionList)
2593 : {
2594 1379 : MergeAction *action = lfirst(lc);
2595 :
2596 1379 : action->qual = pullup_replace_vars(action->qual, rvcontext);
2597 1379 : action->targetList = (List *)
2598 1379 : pullup_replace_vars((Node *) action->targetList, rvcontext);
2599 : }
2600 : }
2601 27740 : parse->mergeJoinCondition = pullup_replace_vars(parse->mergeJoinCondition,
2602 : rvcontext);
2603 27740 : replace_vars_in_jointree((Node *) parse->jointree, rvcontext);
2604 : Assert(parse->setOperations == NULL);
2605 27736 : parse->havingQual = pullup_replace_vars(parse->havingQual, rvcontext);
2606 :
2607 : /*
2608 : * Replace references in the translated_vars lists of appendrels.
2609 : */
2610 27796 : foreach(lc, root->append_rel_list)
2611 : {
2612 60 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(lc);
2613 :
2614 60 : appinfo->translated_vars = (List *)
2615 60 : pullup_replace_vars((Node *) appinfo->translated_vars, rvcontext);
2616 : }
2617 :
2618 : /*
2619 : * Replace references in the joinaliasvars lists of join RTEs and the
2620 : * groupexprs list of group RTE.
2621 : */
2622 77628 : foreach(lc, parse->rtable)
2623 : {
2624 49892 : RangeTblEntry *otherrte = (RangeTblEntry *) lfirst(lc);
2625 :
2626 49892 : if (otherrte->rtekind == RTE_JOIN)
2627 5354 : otherrte->joinaliasvars = (List *)
2628 5354 : pullup_replace_vars((Node *) otherrte->joinaliasvars,
2629 : rvcontext);
2630 44538 : else if (otherrte->rtekind == RTE_GROUP)
2631 673 : otherrte->groupexprs = (List *)
2632 673 : pullup_replace_vars((Node *) otherrte->groupexprs,
2633 : rvcontext);
2634 : }
2635 : }
2636 :
2637 : /*
2638 : * Helper routine for perform_pullup_replace_vars: do pullup_replace_vars on
2639 : * every expression in the jointree, without changing the jointree structure
2640 : * itself. Ugly, but there's no other way...
2641 : */
2642 : static void
2643 72887 : replace_vars_in_jointree(Node *jtnode,
2644 : pullup_replace_vars_context *context)
2645 : {
2646 72887 : if (jtnode == NULL)
2647 0 : return;
2648 72887 : if (IsA(jtnode, RangeTblRef))
2649 : {
2650 : /*
2651 : * If the RangeTblRef refers to a LATERAL subquery (that isn't the
2652 : * same subquery we're pulling up), it might contain references to the
2653 : * target subquery, which we must replace. We drive this from the
2654 : * jointree scan, rather than a scan of the rtable, so that we can
2655 : * avoid processing no-longer-referenced RTEs.
2656 : */
2657 36610 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2658 :
2659 36610 : if (varno != context->varno) /* ignore target subquery itself */
2660 : {
2661 8870 : RangeTblEntry *rte = rt_fetch(varno, context->root->parse->rtable);
2662 :
2663 : Assert(rte != context->target_rte);
2664 8870 : if (rte->lateral)
2665 : {
2666 750 : switch (rte->rtekind)
2667 : {
2668 0 : case RTE_RELATION:
2669 : /* shouldn't be marked LATERAL unless tablesample */
2670 : Assert(rte->tablesample);
2671 0 : rte->tablesample = (TableSampleClause *)
2672 0 : pullup_replace_vars((Node *) rte->tablesample,
2673 : context);
2674 0 : break;
2675 371 : case RTE_SUBQUERY:
2676 371 : rte->subquery =
2677 371 : pullup_replace_vars_subquery(rte->subquery,
2678 : context);
2679 371 : break;
2680 289 : case RTE_FUNCTION:
2681 289 : rte->functions = (List *)
2682 289 : pullup_replace_vars((Node *) rte->functions,
2683 : context);
2684 289 : break;
2685 90 : case RTE_TABLEFUNC:
2686 90 : rte->tablefunc = (TableFunc *)
2687 90 : pullup_replace_vars((Node *) rte->tablefunc,
2688 : context);
2689 90 : break;
2690 0 : case RTE_VALUES:
2691 0 : rte->values_lists = (List *)
2692 0 : pullup_replace_vars((Node *) rte->values_lists,
2693 : context);
2694 0 : break;
2695 0 : case RTE_JOIN:
2696 : case RTE_CTE:
2697 : case RTE_NAMEDTUPLESTORE:
2698 : case RTE_RESULT:
2699 : case RTE_GROUP:
2700 : /* these shouldn't be marked LATERAL */
2701 : Assert(false);
2702 0 : break;
2703 0 : case RTE_GRAPH_TABLE:
2704 : /* shouldn't happen here */
2705 : Assert(false);
2706 0 : break;
2707 : }
2708 : }
2709 : }
2710 : }
2711 36277 : else if (IsA(jtnode, FromExpr))
2712 : {
2713 29944 : FromExpr *f = (FromExpr *) jtnode;
2714 : ListCell *l;
2715 :
2716 62425 : foreach(l, f->fromlist)
2717 32481 : replace_vars_in_jointree(lfirst(l), context);
2718 29944 : f->quals = pullup_replace_vars(f->quals, context);
2719 : }
2720 6333 : else if (IsA(jtnode, JoinExpr))
2721 : {
2722 6333 : JoinExpr *j = (JoinExpr *) jtnode;
2723 6333 : ReplaceWrapOption save_wrap_option = context->wrap_option;
2724 :
2725 6333 : replace_vars_in_jointree(j->larg, context);
2726 6333 : replace_vars_in_jointree(j->rarg, context);
2727 :
2728 : /*
2729 : * Use PHVs within the join quals of a full join for variable-free
2730 : * expressions. Otherwise, we cannot identify which side of the join
2731 : * a pulled-up variable-free expression came from, which can lead to
2732 : * failure to make a plan at all because none of the quals appear to
2733 : * be mergeable or hashable conditions.
2734 : */
2735 6333 : if (j->jointype == JOIN_FULL)
2736 495 : context->wrap_option = REPLACE_WRAP_VARFREE;
2737 :
2738 6333 : j->quals = pullup_replace_vars(j->quals, context);
2739 :
2740 6333 : context->wrap_option = save_wrap_option;
2741 : }
2742 : else
2743 0 : elog(ERROR, "unrecognized node type: %d",
2744 : (int) nodeTag(jtnode));
2745 : }
2746 :
2747 : /*
2748 : * Apply pullup variable replacement throughout an expression tree
2749 : *
2750 : * Returns a modified copy of the tree, so this can't be used where we
2751 : * need to do in-place replacement.
2752 : */
2753 : static Node *
2754 162477 : pullup_replace_vars(Node *expr, pullup_replace_vars_context *context)
2755 : {
2756 162477 : return replace_rte_variables(expr,
2757 : context->varno, 0,
2758 : pullup_replace_vars_callback,
2759 : context,
2760 : context->outer_hasSubLinks);
2761 : }
2762 :
2763 : static Node *
2764 94138 : pullup_replace_vars_callback(const Var *var,
2765 : replace_rte_variables_context *context)
2766 : {
2767 94138 : pullup_replace_vars_context *rcon = (pullup_replace_vars_context *) context->callback_arg;
2768 94138 : int varattno = var->varattno;
2769 : bool need_phv;
2770 : Node *newnode;
2771 :
2772 : /* System columns are not replaced. */
2773 94138 : if (varattno < InvalidAttrNumber)
2774 35 : return (Node *) copyObject(var);
2775 :
2776 : /*
2777 : * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
2778 : * varnullingrels (unless we find below that the replacement expression is
2779 : * a Var or PlaceHolderVar that we can just add the nullingrels to). We
2780 : * also need one if the caller has instructed us that certain expression
2781 : * replacements need to be wrapped for identification purposes.
2782 : */
2783 178633 : need_phv = (var->varnullingrels != NULL) ||
2784 84530 : (rcon->wrap_option != REPLACE_WRAP_NONE);
2785 :
2786 : /*
2787 : * If PlaceHolderVars are needed, we cache the modified expressions in
2788 : * rcon->rv_cache[]. This is not in hopes of any material speed gain
2789 : * within this function, but to avoid generating identical PHVs with
2790 : * different IDs. That would result in duplicate evaluations at runtime,
2791 : * and possibly prevent optimizations that rely on recognizing different
2792 : * references to the same subquery output as being equal(). So it's worth
2793 : * a bit of extra effort to avoid it.
2794 : *
2795 : * The cached items have phlevelsup = 0 and phnullingrels = NULL; we'll
2796 : * copy them and adjust those values for this reference site below.
2797 : */
2798 94103 : if (need_phv &&
2799 11331 : varattno >= InvalidAttrNumber &&
2800 11331 : varattno <= list_length(rcon->targetlist) &&
2801 11331 : rcon->rv_cache[varattno] != NULL)
2802 : {
2803 : /* Just copy the entry and fall through to adjust phlevelsup etc */
2804 2383 : newnode = copyObject(rcon->rv_cache[varattno]);
2805 : }
2806 : else
2807 : {
2808 : /*
2809 : * Generate the replacement expression. This takes care of expanding
2810 : * wholerow references and dealing with non-default varreturningtype.
2811 : */
2812 91720 : newnode = ReplaceVarFromTargetList(var,
2813 : rcon->target_rte,
2814 : rcon->targetlist,
2815 : rcon->result_relation,
2816 : REPLACEVARS_REPORT_ERROR,
2817 : 0);
2818 :
2819 : /* Insert PlaceHolderVar if needed */
2820 91720 : if (need_phv)
2821 : {
2822 : bool wrap;
2823 :
2824 8948 : if (rcon->wrap_option == REPLACE_WRAP_ALL)
2825 : {
2826 : /* Caller told us to wrap all expressions in a PlaceHolderVar */
2827 792 : wrap = true;
2828 : }
2829 8156 : else if (varattno == InvalidAttrNumber)
2830 : {
2831 : /*
2832 : * Insert PlaceHolderVar for whole-tuple reference. Notice
2833 : * that we are wrapping one PlaceHolderVar around the whole
2834 : * RowExpr, rather than putting one around each element of the
2835 : * row. This is because we need the expression to yield NULL,
2836 : * not ROW(NULL,NULL,...) when it is forced to null by an
2837 : * outer join.
2838 : */
2839 55 : wrap = true;
2840 : }
2841 8101 : else if (newnode && IsA(newnode, Var) &&
2842 6498 : ((Var *) newnode)->varlevelsup == 0)
2843 : {
2844 : /*
2845 : * Simple Vars always escape being wrapped, unless they are
2846 : * lateral references to something outside the subquery being
2847 : * pulled up and the referenced rel is not under the same
2848 : * lowest nulling outer join.
2849 : */
2850 6486 : wrap = false;
2851 6486 : if (rcon->target_rte->lateral &&
2852 1175 : !bms_is_member(((Var *) newnode)->varno, rcon->relids))
2853 : {
2854 110 : nullingrel_info *nullinfo = rcon->nullinfo;
2855 110 : int lvarno = ((Var *) newnode)->varno;
2856 :
2857 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2858 110 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2859 110 : nullinfo->nullingrels[lvarno]))
2860 90 : wrap = true;
2861 : }
2862 : }
2863 1615 : else if (newnode && IsA(newnode, PlaceHolderVar) &&
2864 150 : ((PlaceHolderVar *) newnode)->phlevelsup == 0)
2865 : {
2866 : /* The same rules apply for a PlaceHolderVar */
2867 150 : wrap = false;
2868 150 : if (rcon->target_rte->lateral &&
2869 40 : !bms_is_subset(((PlaceHolderVar *) newnode)->phrels,
2870 40 : rcon->relids))
2871 : {
2872 40 : nullingrel_info *nullinfo = rcon->nullinfo;
2873 40 : Relids lvarnos = ((PlaceHolderVar *) newnode)->phrels;
2874 : int lvarno;
2875 :
2876 40 : lvarno = -1;
2877 60 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2878 : {
2879 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2880 40 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2881 40 : nullinfo->nullingrels[lvarno]))
2882 : {
2883 20 : wrap = true;
2884 20 : break;
2885 : }
2886 : }
2887 : }
2888 : }
2889 : else
2890 : {
2891 : /*
2892 : * If the node contains Var(s) or PlaceHolderVar(s) of the
2893 : * subquery being pulled up, or of rels that are under the
2894 : * same lowest nulling outer join as the subquery, and does
2895 : * not contain any non-strict constructs, then instead of
2896 : * adding a PHV on top we can add the required nullingrels to
2897 : * those Vars/PHVs. (This is fundamentally a generalization
2898 : * of the above cases for bare Vars and PHVs.)
2899 : *
2900 : * This test is somewhat expensive, but it avoids pessimizing
2901 : * the plan in cases where the nullingrels get removed again
2902 : * later by outer join reduction.
2903 : *
2904 : * Note that we don't force wrapping of expressions containing
2905 : * lateral references, so long as they also contain Vars/PHVs
2906 : * of the subquery, or of rels that are under the same lowest
2907 : * nulling outer join as the subquery. This is okay because
2908 : * of the restriction to strict constructs: if those Vars/PHVs
2909 : * have been forced to NULL by an outer join then the end
2910 : * result of the expression will be NULL too, regardless of
2911 : * the lateral references. So it's not necessary to force the
2912 : * expression to be evaluated below the outer join. This can
2913 : * be a very valuable optimization, because it may allow us to
2914 : * avoid using a nested loop to pass the lateral reference
2915 : * down.
2916 : *
2917 : * This analysis could be tighter: in particular, a non-strict
2918 : * construct hidden within a lower-level PlaceHolderVar is not
2919 : * reason to add another PHV. But for now it doesn't seem
2920 : * worth the code to be more exact. This is also why it's
2921 : * preferable to handle bare PHVs in the above branch, rather
2922 : * than this branch. We also prefer to handle bare Vars in a
2923 : * separate branch, as it's cheaper this way and parallels the
2924 : * handling of PHVs.
2925 : *
2926 : * For a LATERAL subquery, we have to check the actual var
2927 : * membership of the node, but if it's non-lateral then any
2928 : * level-zero var must belong to the subquery.
2929 : */
2930 1465 : bool contain_nullable_vars = false;
2931 :
2932 1465 : if (!rcon->target_rte->lateral)
2933 : {
2934 1275 : if (contain_vars_of_level(newnode, 0))
2935 443 : contain_nullable_vars = true;
2936 : }
2937 : else
2938 : {
2939 : Relids all_varnos;
2940 :
2941 190 : all_varnos = pull_varnos(rcon->root, newnode);
2942 190 : if (bms_overlap(all_varnos, rcon->relids))
2943 110 : contain_nullable_vars = true;
2944 : else
2945 : {
2946 80 : nullingrel_info *nullinfo = rcon->nullinfo;
2947 : int varno;
2948 :
2949 80 : varno = -1;
2950 150 : while ((varno = bms_next_member(all_varnos, varno)) >= 0)
2951 : {
2952 : Assert(varno > 0 && varno <= nullinfo->rtlength);
2953 90 : if (bms_is_subset(nullinfo->nullingrels[rcon->varno],
2954 90 : nullinfo->nullingrels[varno]))
2955 : {
2956 20 : contain_nullable_vars = true;
2957 20 : break;
2958 : }
2959 : }
2960 : }
2961 : }
2962 :
2963 1465 : if (contain_nullable_vars &&
2964 573 : !contain_nonstrict_functions(newnode))
2965 : {
2966 : /* No wrap needed */
2967 240 : wrap = false;
2968 : }
2969 : else
2970 : {
2971 : /* Else wrap it in a PlaceHolderVar */
2972 1225 : wrap = true;
2973 : }
2974 : }
2975 :
2976 8948 : if (wrap)
2977 : {
2978 : newnode = (Node *)
2979 2182 : make_placeholder_expr(rcon->root,
2980 : (Expr *) newnode,
2981 : bms_make_singleton(rcon->varno));
2982 :
2983 : /*
2984 : * Cache it if possible (ie, if the attno is in range, which
2985 : * it probably always should be).
2986 : */
2987 4364 : if (varattno >= InvalidAttrNumber &&
2988 2182 : varattno <= list_length(rcon->targetlist))
2989 2182 : rcon->rv_cache[varattno] = copyObject(newnode);
2990 : }
2991 : }
2992 : }
2993 :
2994 : /* Propagate any varnullingrels into the replacement expression */
2995 94103 : if (var->varnullingrels != NULL)
2996 : {
2997 9573 : if (IsA(newnode, Var))
2998 : {
2999 6017 : Var *newvar = (Var *) newnode;
3000 :
3001 : Assert(newvar->varlevelsup == 0);
3002 6017 : newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
3003 6017 : var->varnullingrels);
3004 : }
3005 3556 : else if (IsA(newnode, PlaceHolderVar))
3006 : {
3007 3316 : PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
3008 :
3009 : Assert(newphv->phlevelsup == 0);
3010 3316 : newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
3011 3316 : var->varnullingrels);
3012 : }
3013 : else
3014 : {
3015 : /*
3016 : * There should be Vars/PHVs within the expression that we can
3017 : * modify. Vars/PHVs of the subquery should have the full
3018 : * var->varnullingrels added to them, but if there are lateral
3019 : * references within the expression, those must be marked with
3020 : * only the nullingrels that potentially apply to them. (This
3021 : * corresponds to the fact that the expression will now be
3022 : * evaluated at the join level of the Var that we are replacing:
3023 : * the lateral references may have bubbled up through fewer outer
3024 : * joins than the subquery's Vars have. Per the discussion above,
3025 : * we'll still get the right answers.) That relid set could be
3026 : * different for different lateral relations, so we have to do
3027 : * this work for each one.
3028 : *
3029 : * (Currently, the restrictions in is_simple_subquery() mean that
3030 : * at most we have to remove the lowest outer join's relid from
3031 : * the nullingrels of a lateral reference. However, we might
3032 : * relax those restrictions someday, so let's do this right.)
3033 : */
3034 240 : if (rcon->target_rte->lateral)
3035 : {
3036 70 : nullingrel_info *nullinfo = rcon->nullinfo;
3037 : Relids lvarnos;
3038 : int lvarno;
3039 :
3040 : /*
3041 : * Identify lateral varnos used within newnode. We must do
3042 : * this before injecting var->varnullingrels into the tree.
3043 : */
3044 70 : lvarnos = pull_varnos(rcon->root, newnode);
3045 70 : lvarnos = bms_del_members(lvarnos, rcon->relids);
3046 : /* For each one, add relevant nullingrels if any */
3047 70 : lvarno = -1;
3048 140 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
3049 : {
3050 : Relids lnullingrels;
3051 :
3052 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
3053 70 : lnullingrels = bms_intersect(var->varnullingrels,
3054 70 : nullinfo->nullingrels[lvarno]);
3055 70 : if (!bms_is_empty(lnullingrels))
3056 40 : newnode = add_nulling_relids(newnode,
3057 40 : bms_make_singleton(lvarno),
3058 : lnullingrels);
3059 : }
3060 : }
3061 :
3062 : /* Finally, deal with Vars/PHVs of the subquery itself */
3063 240 : newnode = add_nulling_relids(newnode,
3064 240 : rcon->relids,
3065 240 : var->varnullingrels);
3066 : /* Assert we did put the varnullingrels into the expression */
3067 : Assert(bms_is_subset(var->varnullingrels,
3068 : pull_varnos(rcon->root, newnode)));
3069 : }
3070 : }
3071 :
3072 : /* Must adjust varlevelsup if replaced Var is within a subquery */
3073 94103 : if (var->varlevelsup > 0)
3074 880 : IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
3075 :
3076 94103 : return newnode;
3077 : }
3078 :
3079 : /*
3080 : * Apply pullup variable replacement to a subquery
3081 : *
3082 : * This needs to be different from pullup_replace_vars() because
3083 : * replace_rte_variables will think that it shouldn't increment sublevels_up
3084 : * before entering the Query; so we need to call it with sublevels_up == 1.
3085 : */
3086 : static Query *
3087 371 : pullup_replace_vars_subquery(Query *query,
3088 : pullup_replace_vars_context *context)
3089 : {
3090 : Assert(IsA(query, Query));
3091 371 : return (Query *) replace_rte_variables((Node *) query,
3092 : context->varno, 1,
3093 : pullup_replace_vars_callback,
3094 : context,
3095 : NULL);
3096 : }
3097 :
3098 :
3099 : /*
3100 : * flatten_simple_union_all
3101 : * Try to optimize top-level UNION ALL structure into an appendrel
3102 : *
3103 : * If a query's setOperations tree consists entirely of simple UNION ALL
3104 : * operations, flatten it into an append relation, which we can process more
3105 : * intelligently than the general setops case. Otherwise, do nothing.
3106 : *
3107 : * In most cases, this can succeed only for a top-level query, because for a
3108 : * subquery in FROM, the parent query's invocation of pull_up_subqueries would
3109 : * already have flattened the UNION via pull_up_simple_union_all. But there
3110 : * are a few cases we can support here but not in that code path, for example
3111 : * when the subquery also contains ORDER BY.
3112 : */
3113 : void
3114 5455 : flatten_simple_union_all(PlannerInfo *root)
3115 : {
3116 5455 : Query *parse = root->parse;
3117 : SetOperationStmt *topop;
3118 : Node *leftmostjtnode;
3119 : int leftmostRTI;
3120 : RangeTblEntry *leftmostRTE;
3121 : int childRTI;
3122 : RangeTblEntry *childRTE;
3123 : RangeTblRef *rtr;
3124 :
3125 : /* Shouldn't be called unless query has setops */
3126 5455 : topop = castNode(SetOperationStmt, parse->setOperations);
3127 : Assert(topop);
3128 :
3129 : /* Can't optimize away a recursive UNION */
3130 5455 : if (root->hasRecursion)
3131 4912 : return;
3132 :
3133 : /*
3134 : * Recursively check the tree of set operations. If not all UNION ALL
3135 : * with identical column types, punt.
3136 : */
3137 4764 : if (!is_simple_union_all_recurse((Node *) topop, parse, topop->colTypes))
3138 4221 : return;
3139 :
3140 : /*
3141 : * Locate the leftmost leaf query in the setops tree. The upper query's
3142 : * Vars all refer to this RTE (see transformSetOperationStmt).
3143 : */
3144 543 : leftmostjtnode = topop->larg;
3145 773 : while (leftmostjtnode && IsA(leftmostjtnode, SetOperationStmt))
3146 230 : leftmostjtnode = ((SetOperationStmt *) leftmostjtnode)->larg;
3147 : Assert(leftmostjtnode && IsA(leftmostjtnode, RangeTblRef));
3148 543 : leftmostRTI = ((RangeTblRef *) leftmostjtnode)->rtindex;
3149 543 : leftmostRTE = rt_fetch(leftmostRTI, parse->rtable);
3150 : Assert(leftmostRTE->rtekind == RTE_SUBQUERY);
3151 :
3152 : /*
3153 : * Make a copy of the leftmost RTE and add it to the rtable. This copy
3154 : * will represent the leftmost leaf query in its capacity as a member of
3155 : * the appendrel. The original will represent the appendrel as a whole.
3156 : * (We must do things this way because the upper query's Vars have to be
3157 : * seen as referring to the whole appendrel.)
3158 : */
3159 543 : childRTE = copyObject(leftmostRTE);
3160 543 : parse->rtable = lappend(parse->rtable, childRTE);
3161 543 : childRTI = list_length(parse->rtable);
3162 :
3163 : /* Modify the setops tree to reference the child copy */
3164 543 : ((RangeTblRef *) leftmostjtnode)->rtindex = childRTI;
3165 :
3166 : /* Modify the formerly-leftmost RTE to mark it as an appendrel parent */
3167 543 : leftmostRTE->inh = true;
3168 :
3169 : /*
3170 : * Form a RangeTblRef for the appendrel, and insert it into FROM. The top
3171 : * Query of a setops tree should have had an empty FromClause initially.
3172 : */
3173 543 : rtr = makeNode(RangeTblRef);
3174 543 : rtr->rtindex = leftmostRTI;
3175 : Assert(parse->jointree->fromlist == NIL);
3176 543 : parse->jointree->fromlist = list_make1(rtr);
3177 :
3178 : /*
3179 : * Now pretend the query has no setops. We must do this before trying to
3180 : * do subquery pullup, because of Assert in pull_up_simple_subquery.
3181 : */
3182 543 : parse->setOperations = NULL;
3183 :
3184 : /*
3185 : * Build AppendRelInfo information, and apply pull_up_subqueries to the
3186 : * leaf queries of the UNION ALL. (We must do that now because they
3187 : * weren't previously referenced by the jointree, and so were missed by
3188 : * the main invocation of pull_up_subqueries.)
3189 : */
3190 543 : pull_up_union_leaf_queries((Node *) topop, root, leftmostRTI, parse, 0);
3191 : }
3192 :
3193 :
3194 : /*
3195 : * reduce_outer_joins
3196 : * Attempt to reduce outer joins to plain inner joins.
3197 : *
3198 : * The idea here is that given a query like
3199 : * SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
3200 : * we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
3201 : * is strict. The strict operator will always return NULL, causing the outer
3202 : * WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
3203 : * columns. Therefore, there's no need for the join to produce null-extended
3204 : * rows in the first place --- which makes it a plain join not an outer join.
3205 : * (This scenario may not be very likely in a query written out by hand, but
3206 : * it's reasonably likely when pushing quals down into complex views.)
3207 : *
3208 : * More generally, an outer join can be reduced in strength if there is a
3209 : * strict qual above it in the qual tree that constrains a Var from the
3210 : * nullable side of the join to be non-null. (For FULL joins this applies
3211 : * to each side separately.)
3212 : *
3213 : * Another transformation we apply here is to recognize cases like
3214 : * SELECT ... FROM a LEFT JOIN b ON (a.x = b.y) WHERE b.z IS NULL;
3215 : * If we can prove that b.z must be non-null for any matching row, either
3216 : * because the join clause is strict for b.z and b.z happens to be the join
3217 : * key b.y, or because b.z is defined NOT NULL by table constraints and is
3218 : * not nullable due to lower-level outer joins, then only null-extended rows
3219 : * could pass the upper WHERE, and we can conclude that what the query is
3220 : * really specifying is an anti-semijoin. We change the join type from
3221 : * JOIN_LEFT to JOIN_ANTI. The IS NULL clause then becomes redundant, and
3222 : * must be removed to prevent bogus selectivity calculations, but we leave
3223 : * it to distribute_qual_to_rels to get rid of such clauses.
3224 : *
3225 : * Also, we get rid of JOIN_RIGHT cases by flipping them around to become
3226 : * JOIN_LEFT. This saves some code here and in some later planner routines;
3227 : * the main benefit is to reduce the number of jointypes that can appear in
3228 : * SpecialJoinInfo nodes. Note that we can still generate Paths and Plans
3229 : * that use JOIN_RIGHT (or JOIN_RIGHT_ANTI) by switching the inputs again.
3230 : *
3231 : * To ease recognition of strict qual clauses, we require this routine to be
3232 : * run after expression preprocessing (i.e., qual canonicalization and JOIN
3233 : * alias-var expansion).
3234 : */
3235 : void
3236 25691 : reduce_outer_joins(PlannerInfo *root)
3237 : {
3238 : reduce_outer_joins_pass1_state *state1;
3239 : reduce_outer_joins_pass2_state state2;
3240 : ListCell *lc;
3241 :
3242 : /*
3243 : * To avoid doing strictness checks on more quals than necessary, we want
3244 : * to stop descending the jointree as soon as there are no outer joins
3245 : * below our current point. This consideration forces a two-pass process.
3246 : * The first pass gathers information about which base rels appear below
3247 : * each side of each join clause, about whether there are outer join(s)
3248 : * below each side of each join clause, and about which base rels are from
3249 : * the nullable side of those outer join(s). The second pass examines
3250 : * qual clauses and changes join types as it descends the tree.
3251 : */
3252 25691 : state1 = reduce_outer_joins_pass1((Node *) root->parse->jointree);
3253 :
3254 : /* planner.c shouldn't have called me if no outer joins */
3255 25691 : if (state1 == NULL || !state1->contains_outer)
3256 0 : elog(ERROR, "so where are the outer joins?");
3257 :
3258 25691 : state2.inner_reduced = NULL;
3259 25691 : state2.partial_reduced = NIL;
3260 :
3261 25691 : reduce_outer_joins_pass2((Node *) root->parse->jointree,
3262 : state1, &state2,
3263 : root, NULL, NIL);
3264 :
3265 : /*
3266 : * If we successfully reduced the strength of any outer joins, we must
3267 : * remove references to those joins as nulling rels. This is handled as
3268 : * an additional pass, for simplicity and because we can handle all
3269 : * fully-reduced joins in a single pass over the parse tree.
3270 : */
3271 25691 : if (!bms_is_empty(state2.inner_reduced))
3272 : {
3273 2028 : root->parse = (Query *)
3274 2028 : remove_nulling_relids((Node *) root->parse,
3275 2028 : state2.inner_reduced,
3276 : NULL);
3277 : /* There could be references in the append_rel_list, too */
3278 2028 : root->append_rel_list = (List *)
3279 2028 : remove_nulling_relids((Node *) root->append_rel_list,
3280 2028 : state2.inner_reduced,
3281 : NULL);
3282 : }
3283 :
3284 : /*
3285 : * Partially-reduced full joins have to be done one at a time, since
3286 : * they'll each need a different setting of except_relids.
3287 : */
3288 25730 : foreach(lc, state2.partial_reduced)
3289 : {
3290 39 : reduce_outer_joins_partial_state *statep = lfirst(lc);
3291 39 : Relids full_join_relids = bms_make_singleton(statep->full_join_rti);
3292 :
3293 39 : root->parse = (Query *)
3294 39 : remove_nulling_relids((Node *) root->parse,
3295 : full_join_relids,
3296 39 : statep->unreduced_side);
3297 39 : root->append_rel_list = (List *)
3298 39 : remove_nulling_relids((Node *) root->append_rel_list,
3299 : full_join_relids,
3300 39 : statep->unreduced_side);
3301 : }
3302 25691 : }
3303 :
3304 : /*
3305 : * reduce_outer_joins_pass1 - phase 1 data collection
3306 : *
3307 : * Returns a state node describing the given jointree node.
3308 : */
3309 : static reduce_outer_joins_pass1_state *
3310 146353 : reduce_outer_joins_pass1(Node *jtnode)
3311 : {
3312 : reduce_outer_joins_pass1_state *result;
3313 :
3314 146353 : result = palloc_object(reduce_outer_joins_pass1_state);
3315 146353 : result->relids = NULL;
3316 146353 : result->contains_outer = false;
3317 146353 : result->nullable_rels = NULL;
3318 146353 : result->sub_states = NIL;
3319 :
3320 146353 : if (jtnode == NULL)
3321 0 : return result;
3322 146353 : if (IsA(jtnode, RangeTblRef))
3323 : {
3324 73090 : int varno = ((RangeTblRef *) jtnode)->rtindex;
3325 :
3326 73090 : result->relids = bms_make_singleton(varno);
3327 : }
3328 73263 : else if (IsA(jtnode, FromExpr))
3329 : {
3330 28302 : FromExpr *f = (FromExpr *) jtnode;
3331 : ListCell *l;
3332 :
3333 59042 : foreach(l, f->fromlist)
3334 : {
3335 : reduce_outer_joins_pass1_state *sub_state;
3336 :
3337 30740 : sub_state = reduce_outer_joins_pass1(lfirst(l));
3338 61480 : result->relids = bms_add_members(result->relids,
3339 30740 : sub_state->relids);
3340 30740 : result->contains_outer |= sub_state->contains_outer;
3341 61480 : result->nullable_rels = bms_add_members(result->nullable_rels,
3342 30740 : sub_state->nullable_rels);
3343 30740 : result->sub_states = lappend(result->sub_states, sub_state);
3344 : }
3345 : }
3346 44961 : else if (IsA(jtnode, JoinExpr))
3347 : {
3348 44961 : JoinExpr *j = (JoinExpr *) jtnode;
3349 : reduce_outer_joins_pass1_state *left_state;
3350 : reduce_outer_joins_pass1_state *right_state;
3351 :
3352 : /* Recurse to children */
3353 44961 : left_state = reduce_outer_joins_pass1(j->larg);
3354 44961 : right_state = reduce_outer_joins_pass1(j->rarg);
3355 :
3356 : /* join's own RT index is not wanted in result->relids */
3357 44961 : result->relids = bms_union(left_state->relids, right_state->relids);
3358 :
3359 : /* Store children's states for pass 2 */
3360 44961 : result->sub_states = list_make2(left_state, right_state);
3361 :
3362 : /* Collect outer join information */
3363 44961 : switch (j->jointype)
3364 : {
3365 7651 : case JOIN_INNER:
3366 : case JOIN_SEMI:
3367 : /* No new nullability; propagate state from children */
3368 14688 : result->contains_outer = left_state->contains_outer ||
3369 7037 : right_state->contains_outer;
3370 15302 : result->nullable_rels = bms_union(left_state->nullable_rels,
3371 7651 : right_state->nullable_rels);
3372 7651 : break;
3373 35497 : case JOIN_LEFT:
3374 : case JOIN_ANTI:
3375 : /* RHS is nullable; LHS keeps existing status */
3376 35497 : result->contains_outer = true;
3377 70994 : result->nullable_rels = bms_union(left_state->nullable_rels,
3378 35497 : right_state->relids);
3379 35497 : break;
3380 955 : case JOIN_RIGHT:
3381 : /* LHS is nullable; RHS keeps existing status */
3382 955 : result->contains_outer = true;
3383 1910 : result->nullable_rels = bms_union(left_state->relids,
3384 955 : right_state->nullable_rels);
3385 955 : break;
3386 858 : case JOIN_FULL:
3387 : /* Both sides are nullable */
3388 858 : result->contains_outer = true;
3389 1716 : result->nullable_rels = bms_union(left_state->relids,
3390 858 : right_state->relids);
3391 858 : break;
3392 0 : default:
3393 0 : elog(ERROR, "unrecognized join type: %d",
3394 : (int) j->jointype);
3395 : break;
3396 : }
3397 : }
3398 : else
3399 0 : elog(ERROR, "unrecognized node type: %d",
3400 : (int) nodeTag(jtnode));
3401 146353 : return result;
3402 : }
3403 :
3404 : /*
3405 : * reduce_outer_joins_pass2 - phase 2 processing
3406 : *
3407 : * jtnode: current jointree node
3408 : * state1: state data collected by phase 1 for this node
3409 : * state2: where to accumulate info about successfully-reduced joins
3410 : * root: toplevel planner state
3411 : * nonnullable_rels: set of base relids forced non-null by upper quals
3412 : * forced_null_vars: multibitmapset of Vars forced null by upper quals
3413 : *
3414 : * Returns info in state2 about outer joins that were successfully simplified.
3415 : * Joins that were fully reduced to inner joins are all added to
3416 : * state2->inner_reduced. If a full join is reduced to a left join,
3417 : * it needs its own entry in state2->partial_reduced, since that will
3418 : * require custom processing to remove only the correct nullingrel markers.
3419 : */
3420 : static void
3421 64873 : reduce_outer_joins_pass2(Node *jtnode,
3422 : reduce_outer_joins_pass1_state *state1,
3423 : reduce_outer_joins_pass2_state *state2,
3424 : PlannerInfo *root,
3425 : Relids nonnullable_rels,
3426 : List *forced_null_vars)
3427 : {
3428 : /*
3429 : * pass 2 should never descend as far as an empty subnode or base rel,
3430 : * because it's only called on subtrees marked as contains_outer.
3431 : */
3432 64873 : if (jtnode == NULL)
3433 0 : elog(ERROR, "reached empty jointree");
3434 64873 : if (IsA(jtnode, RangeTblRef))
3435 0 : elog(ERROR, "reached base rel");
3436 64873 : else if (IsA(jtnode, FromExpr))
3437 : {
3438 26835 : FromExpr *f = (FromExpr *) jtnode;
3439 : ListCell *l;
3440 : ListCell *s;
3441 : Relids pass_nonnullable_rels;
3442 : List *pass_forced_null_vars;
3443 :
3444 : /* Scan quals to see if we can add any constraints */
3445 26835 : pass_nonnullable_rels = find_nonnullable_rels(f->quals);
3446 26835 : pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels,
3447 : nonnullable_rels);
3448 26835 : pass_forced_null_vars = find_forced_null_vars(f->quals);
3449 26835 : pass_forced_null_vars = mbms_add_members(pass_forced_null_vars,
3450 : forced_null_vars);
3451 : /* And recurse --- but only into interesting subtrees */
3452 : Assert(list_length(f->fromlist) == list_length(state1->sub_states));
3453 55973 : forboth(l, f->fromlist, s, state1->sub_states)
3454 : {
3455 29138 : reduce_outer_joins_pass1_state *sub_state = lfirst(s);
3456 :
3457 29138 : if (sub_state->contains_outer)
3458 26860 : reduce_outer_joins_pass2(lfirst(l), sub_state,
3459 : state2, root,
3460 : pass_nonnullable_rels,
3461 : pass_forced_null_vars);
3462 : }
3463 26835 : bms_free(pass_nonnullable_rels);
3464 : /* can't so easily clean up var lists, unfortunately */
3465 : }
3466 38038 : else if (IsA(jtnode, JoinExpr))
3467 : {
3468 38038 : JoinExpr *j = (JoinExpr *) jtnode;
3469 38038 : int rtindex = j->rtindex;
3470 38038 : JoinType jointype = j->jointype;
3471 38038 : reduce_outer_joins_pass1_state *left_state = linitial(state1->sub_states);
3472 38038 : reduce_outer_joins_pass1_state *right_state = lsecond(state1->sub_states);
3473 :
3474 : /* Can we simplify this join? */
3475 38038 : switch (jointype)
3476 : {
3477 681 : case JOIN_INNER:
3478 681 : break;
3479 35167 : case JOIN_LEFT:
3480 35167 : if (bms_overlap(nonnullable_rels, right_state->relids))
3481 2265 : jointype = JOIN_INNER;
3482 35167 : break;
3483 955 : case JOIN_RIGHT:
3484 955 : if (bms_overlap(nonnullable_rels, left_state->relids))
3485 64 : jointype = JOIN_INNER;
3486 955 : break;
3487 858 : case JOIN_FULL:
3488 858 : if (bms_overlap(nonnullable_rels, left_state->relids))
3489 : {
3490 20 : if (bms_overlap(nonnullable_rels, right_state->relids))
3491 10 : jointype = JOIN_INNER;
3492 : else
3493 : {
3494 10 : jointype = JOIN_LEFT;
3495 : /* Also report partial reduction in state2 */
3496 10 : report_reduced_full_join(state2, rtindex,
3497 : right_state->relids);
3498 : }
3499 : }
3500 : else
3501 : {
3502 838 : if (bms_overlap(nonnullable_rels, right_state->relids))
3503 : {
3504 29 : jointype = JOIN_RIGHT;
3505 : /* Also report partial reduction in state2 */
3506 29 : report_reduced_full_join(state2, rtindex,
3507 : left_state->relids);
3508 : }
3509 : }
3510 858 : break;
3511 377 : case JOIN_SEMI:
3512 : case JOIN_ANTI:
3513 :
3514 : /*
3515 : * These could only have been introduced by pull_up_sublinks,
3516 : * so there's no way that upper quals could refer to their
3517 : * righthand sides, and no point in checking. We don't expect
3518 : * to see JOIN_RIGHT_SEMI or JOIN_RIGHT_ANTI yet.
3519 : */
3520 377 : break;
3521 0 : default:
3522 0 : elog(ERROR, "unrecognized join type: %d",
3523 : (int) jointype);
3524 : break;
3525 : }
3526 :
3527 : /*
3528 : * Convert JOIN_RIGHT to JOIN_LEFT. Note that in the case where we
3529 : * reduced JOIN_FULL to JOIN_RIGHT, this will mean the JoinExpr no
3530 : * longer matches the internal ordering of any CoalesceExpr's built to
3531 : * represent merged join variables. We don't care about that at
3532 : * present, but be wary of it ...
3533 : */
3534 38038 : if (jointype == JOIN_RIGHT)
3535 : {
3536 : Node *tmparg;
3537 :
3538 920 : tmparg = j->larg;
3539 920 : j->larg = j->rarg;
3540 920 : j->rarg = tmparg;
3541 920 : jointype = JOIN_LEFT;
3542 920 : right_state = linitial(state1->sub_states);
3543 920 : left_state = lsecond(state1->sub_states);
3544 : }
3545 :
3546 : /*
3547 : * See if we can reduce JOIN_LEFT to JOIN_ANTI. This is the case if
3548 : * any var from the RHS was forced null by higher qual levels, but is
3549 : * known to be non-nullable. We detect this either by seeing if the
3550 : * join's own quals are strict for the var, or by checking if the var
3551 : * is defined NOT NULL by table constraints (being careful to exclude
3552 : * vars that are nullable due to lower-level outer joins). In either
3553 : * case, the only way the higher qual clause's requirement for NULL
3554 : * can be met is if the join fails to match, producing a null-extended
3555 : * row. Thus, we can treat this as an anti-join.
3556 : */
3557 38038 : if (jointype == JOIN_LEFT && forced_null_vars != NIL)
3558 : {
3559 : List *nonnullable_vars;
3560 : Bitmapset *overlap;
3561 :
3562 : /* Find Vars in j->quals that must be non-null in joined rows */
3563 1003 : nonnullable_vars = find_nonnullable_vars(j->quals);
3564 :
3565 : /*
3566 : * It's not sufficient to check whether nonnullable_vars and
3567 : * forced_null_vars overlap: we need to know if the overlap
3568 : * includes any RHS variables.
3569 : *
3570 : * Also check if any forced-null var is defined NOT NULL by table
3571 : * constraints.
3572 : */
3573 1003 : overlap = mbms_overlap_sets(nonnullable_vars, forced_null_vars);
3574 1157 : if (bms_overlap(overlap, right_state->relids) ||
3575 154 : has_notnull_forced_var(root, forced_null_vars, right_state))
3576 869 : jointype = JOIN_ANTI;
3577 : }
3578 :
3579 : /*
3580 : * Apply the jointype change, if any, to both jointree node and RTE.
3581 : * Also, if we changed an RTE to INNER, add its RTI to inner_reduced.
3582 : */
3583 38038 : if (rtindex && jointype != j->jointype)
3584 : {
3585 4138 : RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
3586 :
3587 : Assert(rte->rtekind == RTE_JOIN);
3588 : Assert(rte->jointype == j->jointype);
3589 4138 : rte->jointype = jointype;
3590 4138 : if (jointype == JOIN_INNER)
3591 2339 : state2->inner_reduced = bms_add_member(state2->inner_reduced,
3592 : rtindex);
3593 : }
3594 38038 : j->jointype = jointype;
3595 :
3596 : /* Only recurse if there's more to do below here */
3597 38038 : if (left_state->contains_outer || right_state->contains_outer)
3598 : {
3599 : Relids local_nonnullable_rels;
3600 : List *local_forced_null_vars;
3601 : Relids pass_nonnullable_rels;
3602 : List *pass_forced_null_vars;
3603 :
3604 : /*
3605 : * If this join is (now) inner, we can add any constraints its
3606 : * quals provide to those we got from above. But if it is outer,
3607 : * we can pass down the local constraints only into the nullable
3608 : * side, because an outer join never eliminates any rows from its
3609 : * non-nullable side. Also, there is no point in passing upper
3610 : * constraints into the nullable side, since if there were any
3611 : * we'd have been able to reduce the join. (In the case of upper
3612 : * forced-null constraints, we *must not* pass them into the
3613 : * nullable side --- they either applied here, or not.) The upshot
3614 : * is that we pass either the local or the upper constraints,
3615 : * never both, to the children of an outer join.
3616 : *
3617 : * Note that a SEMI join works like an inner join here: it's okay
3618 : * to pass down both local and upper constraints. (There can't be
3619 : * any upper constraints affecting its inner side, but it's not
3620 : * worth having a separate code path to avoid passing them.)
3621 : *
3622 : * At a FULL join we just punt and pass nothing down --- is it
3623 : * possible to be smarter?
3624 : */
3625 12268 : if (jointype != JOIN_FULL)
3626 : {
3627 12170 : local_nonnullable_rels = find_nonnullable_rels(j->quals);
3628 12170 : local_forced_null_vars = find_forced_null_vars(j->quals);
3629 12170 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3630 : {
3631 : /* OK to merge upper and local constraints */
3632 1485 : local_nonnullable_rels = bms_add_members(local_nonnullable_rels,
3633 : nonnullable_rels);
3634 1485 : local_forced_null_vars = mbms_add_members(local_forced_null_vars,
3635 : forced_null_vars);
3636 : }
3637 : }
3638 : else
3639 : {
3640 : /* no use in calculating these */
3641 98 : local_nonnullable_rels = NULL;
3642 98 : local_forced_null_vars = NIL;
3643 : }
3644 :
3645 12268 : if (left_state->contains_outer)
3646 : {
3647 11634 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3648 : {
3649 : /* pass union of local and upper constraints */
3650 1315 : pass_nonnullable_rels = local_nonnullable_rels;
3651 1315 : pass_forced_null_vars = local_forced_null_vars;
3652 : }
3653 10319 : else if (jointype != JOIN_FULL) /* ie, LEFT or ANTI */
3654 : {
3655 : /* can't pass local constraints to non-nullable side */
3656 10239 : pass_nonnullable_rels = nonnullable_rels;
3657 10239 : pass_forced_null_vars = forced_null_vars;
3658 : }
3659 : else
3660 : {
3661 : /* no constraints pass through JOIN_FULL */
3662 80 : pass_nonnullable_rels = NULL;
3663 80 : pass_forced_null_vars = NIL;
3664 : }
3665 11634 : reduce_outer_joins_pass2(j->larg, left_state,
3666 : state2, root,
3667 : pass_nonnullable_rels,
3668 : pass_forced_null_vars);
3669 : }
3670 :
3671 12268 : if (right_state->contains_outer)
3672 : {
3673 688 : if (jointype != JOIN_FULL) /* ie, INNER/LEFT/SEMI/ANTI */
3674 : {
3675 : /* pass appropriate constraints, per comment above */
3676 670 : pass_nonnullable_rels = local_nonnullable_rels;
3677 670 : pass_forced_null_vars = local_forced_null_vars;
3678 : }
3679 : else
3680 : {
3681 : /* no constraints pass through JOIN_FULL */
3682 18 : pass_nonnullable_rels = NULL;
3683 18 : pass_forced_null_vars = NIL;
3684 : }
3685 688 : reduce_outer_joins_pass2(j->rarg, right_state,
3686 : state2, root,
3687 : pass_nonnullable_rels,
3688 : pass_forced_null_vars);
3689 : }
3690 12268 : bms_free(local_nonnullable_rels);
3691 : }
3692 : }
3693 : else
3694 0 : elog(ERROR, "unrecognized node type: %d",
3695 : (int) nodeTag(jtnode));
3696 64873 : }
3697 :
3698 : /* Helper for reduce_outer_joins_pass2 */
3699 : static void
3700 39 : report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
3701 : int rtindex, Relids relids)
3702 : {
3703 : reduce_outer_joins_partial_state *statep;
3704 :
3705 39 : statep = palloc_object(reduce_outer_joins_partial_state);
3706 39 : statep->full_join_rti = rtindex;
3707 39 : statep->unreduced_side = relids;
3708 39 : state2->partial_reduced = lappend(state2->partial_reduced, statep);
3709 39 : }
3710 :
3711 : /*
3712 : * has_notnull_forced_var
3713 : * Check if "forced_null_vars" contains any Vars belonging to the subtree
3714 : * indicated by "right_state" that are known to be non-nullable due to
3715 : * table constraints.
3716 : *
3717 : * Note that we must also consider the situation where a NOT NULL Var can be
3718 : * nulled by lower-level outer joins.
3719 : *
3720 : * Helper for reduce_outer_joins_pass2.
3721 : */
3722 : static bool
3723 154 : has_notnull_forced_var(PlannerInfo *root, List *forced_null_vars,
3724 : reduce_outer_joins_pass1_state *right_state)
3725 : {
3726 154 : int varno = -1;
3727 :
3728 1246 : foreach_node(Bitmapset, attrs, forced_null_vars)
3729 : {
3730 : RangeTblEntry *rte;
3731 : Bitmapset *notnullattnums;
3732 978 : Bitmapset *forcednullattnums = NULL;
3733 : int attno;
3734 :
3735 978 : varno++;
3736 :
3737 : /* Skip empty bitmaps */
3738 978 : if (bms_is_empty(attrs))
3739 824 : continue;
3740 :
3741 : /* Skip Vars that do not belong to the target relations */
3742 154 : if (!bms_is_member(varno, right_state->relids))
3743 65 : continue;
3744 :
3745 : /*
3746 : * Skip Vars that can be nulled by lower-level outer joins within the
3747 : * given subtree. These Vars might be NULL even if the schema defines
3748 : * them as NOT NULL.
3749 : */
3750 89 : if (bms_is_member(varno, right_state->nullable_rels))
3751 5 : continue;
3752 :
3753 : /*
3754 : * Iterate over attributes and adjust the bitmap indexes by
3755 : * FirstLowInvalidHeapAttributeNumber to get the actual attribute
3756 : * numbers.
3757 : */
3758 84 : attno = -1;
3759 168 : while ((attno = bms_next_member(attrs, attno)) >= 0)
3760 : {
3761 84 : AttrNumber real_attno = attno + FirstLowInvalidHeapAttributeNumber;
3762 :
3763 : /* system columns cannot be NULL */
3764 84 : if (real_attno < 0)
3765 20 : return true;
3766 :
3767 84 : forcednullattnums = bms_add_member(forcednullattnums, real_attno);
3768 : }
3769 :
3770 84 : rte = rt_fetch(varno, root->parse->rtable);
3771 :
3772 : /* We can only reason about ordinary relations */
3773 84 : if (rte->rtekind != RTE_RELATION)
3774 : {
3775 34 : bms_free(forcednullattnums);
3776 34 : continue;
3777 : }
3778 :
3779 : /*
3780 : * We must skip inheritance parent tables, as some child tables may
3781 : * have a NOT NULL constraint for a column while others may not. This
3782 : * cannot happen with partitioned tables, though.
3783 : */
3784 50 : if (rte->inh && rte->relkind != RELKIND_PARTITIONED_TABLE)
3785 : {
3786 0 : bms_free(forcednullattnums);
3787 0 : continue;
3788 : }
3789 :
3790 : /* Get the column not-null constraint information for this relation */
3791 50 : notnullattnums = find_relation_notnullatts(root, rte->relid);
3792 :
3793 : /*
3794 : * Check if any forced-null attributes are defined as NOT NULL by
3795 : * table constraints.
3796 : */
3797 50 : if (bms_overlap(notnullattnums, forcednullattnums))
3798 : {
3799 20 : bms_free(forcednullattnums);
3800 20 : return true;
3801 : }
3802 :
3803 30 : bms_free(forcednullattnums);
3804 : }
3805 :
3806 134 : return false;
3807 : }
3808 :
3809 :
3810 : /*
3811 : * remove_useless_result_rtes
3812 : * Attempt to remove RTE_RESULT RTEs from the join tree.
3813 : * Also, elide single-child FromExprs where possible.
3814 : *
3815 : * We can remove RTE_RESULT entries from the join tree using the knowledge
3816 : * that RTE_RESULT returns exactly one row and has no output columns. Hence,
3817 : * if one is inner-joined to anything else, we can delete it. Optimizations
3818 : * are also possible for some outer-join cases, as detailed below.
3819 : *
3820 : * This pass also replaces single-child FromExprs with their child node
3821 : * where possible. It's appropriate to do that here and not earlier because
3822 : * RTE_RESULT removal might reduce a multiple-child FromExpr to have only one
3823 : * child. We can remove such a FromExpr if its quals are empty, or if it's
3824 : * semantically valid to merge the quals into those of the parent node.
3825 : * While removing unnecessary join tree nodes has some micro-efficiency value,
3826 : * the real reason to do this is to eliminate cases where the nullable side of
3827 : * an outer join node is a FromExpr whose single child is another outer join.
3828 : * To correctly determine whether the two outer joins can commute,
3829 : * deconstruct_jointree() must treat any quals of such a FromExpr as being
3830 : * degenerate quals of the upper outer join. The best way to do that is to
3831 : * make them actually *be* quals of the upper join, by dropping the FromExpr
3832 : * and hoisting the quals up into the upper join's quals. (Note that there is
3833 : * no hazard when the intermediate FromExpr has multiple children, since then
3834 : * it represents an inner join that cannot commute with the upper outer join.)
3835 : * As long as we have to do that, we might as well elide such FromExprs
3836 : * everywhere.
3837 : *
3838 : * Some of these optimizations depend on recognizing empty (constant-true)
3839 : * quals for FromExprs and JoinExprs. That makes it useful to apply this
3840 : * optimization pass after expression preprocessing, since that will have
3841 : * eliminated constant-true quals, allowing more cases to be recognized as
3842 : * optimizable. What's more, the usual reason for an RTE_RESULT to be present
3843 : * is that we pulled up a subquery or VALUES clause, thus very possibly
3844 : * replacing Vars with constants, making it more likely that a qual can be
3845 : * reduced to constant true. Also, because some optimizations depend on
3846 : * the outer-join type, it's best to have done reduce_outer_joins() first.
3847 : *
3848 : * A PlaceHolderVar referencing an RTE_RESULT RTE poses an obstacle to this
3849 : * process: we must remove the RTE_RESULT's relid from the PHV's phrels, but
3850 : * we must not reduce the phrels set to empty. If that would happen, and
3851 : * the RTE_RESULT is an immediate child of an outer join, we have to give up
3852 : * and not remove the RTE_RESULT: there is noplace else to evaluate the
3853 : * PlaceHolderVar. (That is, in such cases the RTE_RESULT *does* have output
3854 : * columns.) But if the RTE_RESULT is an immediate child of an inner join,
3855 : * we can usually change the PlaceHolderVar's phrels so as to evaluate it at
3856 : * the inner join instead. This is OK because we really only care that PHVs
3857 : * are evaluated above or below the correct outer joins. We can't, however,
3858 : * postpone the evaluation of a PHV to above where it is used; so there are
3859 : * some checks below on whether output PHVs are laterally referenced in the
3860 : * other join input rel(s).
3861 : *
3862 : * We used to try to do this work as part of pull_up_subqueries() where the
3863 : * potentially-optimizable cases get introduced; but it's way simpler, and
3864 : * more effective, to do it separately.
3865 : */
3866 : void
3867 166564 : remove_useless_result_rtes(PlannerInfo *root)
3868 : {
3869 166564 : Relids dropped_outer_joins = NULL;
3870 : ListCell *cell;
3871 :
3872 : /* Top level of jointree must always be a FromExpr */
3873 : Assert(IsA(root->parse->jointree, FromExpr));
3874 : /* Recurse ... */
3875 333128 : root->parse->jointree = (FromExpr *)
3876 166564 : remove_useless_results_recurse(root,
3877 166564 : (Node *) root->parse->jointree,
3878 : NULL,
3879 : &dropped_outer_joins);
3880 : /* We should still have a FromExpr */
3881 : Assert(IsA(root->parse->jointree, FromExpr));
3882 :
3883 : /*
3884 : * If we removed any outer-join nodes from the jointree, run around and
3885 : * remove references to those joins as nulling rels. (There could be such
3886 : * references in PHVs that we pulled up out of the original subquery that
3887 : * the RESULT rel replaced. This is kosher on the grounds that we now
3888 : * know that such an outer join wouldn't really have nulled anything.) We
3889 : * don't do this during the main recursion, for simplicity and because we
3890 : * can handle all such joins in a single pass over the parse tree.
3891 : */
3892 166564 : if (!bms_is_empty(dropped_outer_joins))
3893 : {
3894 50 : root->parse = (Query *)
3895 50 : remove_nulling_relids((Node *) root->parse,
3896 : dropped_outer_joins,
3897 : NULL);
3898 : /* There could be references in the append_rel_list, too */
3899 50 : root->append_rel_list = (List *)
3900 50 : remove_nulling_relids((Node *) root->append_rel_list,
3901 : dropped_outer_joins,
3902 : NULL);
3903 : }
3904 :
3905 : /*
3906 : * Remove any PlanRowMark referencing an RTE_RESULT RTE. We obviously
3907 : * must do that for any RTE_RESULT that we just removed. But one for a
3908 : * RTE that we did not remove can be dropped anyway: since the RTE has
3909 : * only one possible output row, there is no need for EPQ to mark and
3910 : * restore that row.
3911 : *
3912 : * It's necessary, not optional, to remove the PlanRowMark for a surviving
3913 : * RTE_RESULT RTE; otherwise we'll generate a whole-row Var for the
3914 : * RTE_RESULT, which the executor has no support for.
3915 : */
3916 168126 : foreach(cell, root->rowMarks)
3917 : {
3918 1562 : PlanRowMark *rc = (PlanRowMark *) lfirst(cell);
3919 :
3920 1562 : if (rt_fetch(rc->rti, root->parse->rtable)->rtekind == RTE_RESULT)
3921 646 : root->rowMarks = foreach_delete_current(root->rowMarks, cell);
3922 : }
3923 166564 : }
3924 :
3925 : /*
3926 : * remove_useless_results_recurse
3927 : * Recursive guts of remove_useless_result_rtes.
3928 : *
3929 : * This recursively processes the jointree and returns a modified jointree.
3930 : * In addition, the RT indexes of any removed outer-join nodes are added to
3931 : * *dropped_outer_joins.
3932 : *
3933 : * jtnode is the current jointree node. If it could be valid to merge
3934 : * its quals into those of the parent node, parent_quals should point to
3935 : * the parent's quals list; otherwise, pass NULL for parent_quals.
3936 : * (Note that in some cases, parent_quals points to the quals of a parent
3937 : * more than one level up in the tree.)
3938 : */
3939 : static Node *
3940 437935 : remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
3941 : Node **parent_quals,
3942 : Relids *dropped_outer_joins)
3943 : {
3944 : Assert(jtnode != NULL);
3945 437935 : if (IsA(jtnode, RangeTblRef))
3946 : {
3947 : /* Can't immediately do anything with a RangeTblRef */
3948 : }
3949 220272 : else if (IsA(jtnode, FromExpr))
3950 : {
3951 172199 : FromExpr *f = (FromExpr *) jtnode;
3952 172199 : Relids result_relids = NULL;
3953 : ListCell *cell;
3954 :
3955 : /*
3956 : * We can drop RTE_RESULT rels from the fromlist so long as at least
3957 : * one child remains, since joining to a one-row table changes
3958 : * nothing. (But we can't drop a RTE_RESULT that computes PHV(s) that
3959 : * are needed by some sibling. The cleanup transformation below would
3960 : * reassign the PHVs to be computed at the join, which is too late for
3961 : * the sibling's use.) The easiest way to mechanize this rule is to
3962 : * modify the list in-place.
3963 : */
3964 347424 : foreach(cell, f->fromlist)
3965 : {
3966 175225 : Node *child = (Node *) lfirst(cell);
3967 : int varno;
3968 :
3969 : /* Recursively transform child, allowing it to push up quals ... */
3970 175225 : child = remove_useless_results_recurse(root, child,
3971 : &f->quals,
3972 : dropped_outer_joins);
3973 : /* ... and stick it back into the tree */
3974 175225 : lfirst(cell) = child;
3975 :
3976 : /*
3977 : * If it's an RTE_RESULT with at least one sibling, and no sibling
3978 : * references dependent PHVs, we can drop it. We don't yet know
3979 : * what the inner join's final relid set will be, so postpone
3980 : * cleanup of PHVs etc till after this loop.
3981 : */
3982 180099 : if (list_length(f->fromlist) > 1 &&
3983 4874 : (varno = get_result_relid(root, child)) != 0 &&
3984 278 : !find_dependent_phvs_in_jointree(root, (Node *) f, varno))
3985 : {
3986 258 : f->fromlist = foreach_delete_current(f->fromlist, cell);
3987 258 : result_relids = bms_add_member(result_relids, varno);
3988 : }
3989 : }
3990 :
3991 : /*
3992 : * Clean up if we dropped any RTE_RESULT RTEs. This is a bit
3993 : * inefficient if there's more than one, but it seems better to
3994 : * optimize the support code for the single-relid case.
3995 : */
3996 172199 : if (result_relids)
3997 : {
3998 248 : int varno = -1;
3999 :
4000 506 : while ((varno = bms_next_member(result_relids, varno)) >= 0)
4001 258 : remove_result_refs(root, varno, (Node *) f);
4002 : }
4003 :
4004 : /*
4005 : * If the FromExpr now has only one child, see if we can elide it.
4006 : * This is always valid if there are no quals, except at the top of
4007 : * the jointree (since Query.jointree is required to point to a
4008 : * FromExpr). Otherwise, we can do it if we can push the quals up to
4009 : * the parent node.
4010 : *
4011 : * Note: while it would not be terribly hard to generalize this
4012 : * transformation to merge multi-child FromExprs into their parent
4013 : * FromExpr, that risks making the parent join too expensive to plan.
4014 : * We leave it to later processing to decide heuristically whether
4015 : * that's a good idea. Pulling up a single child is always OK,
4016 : * however.
4017 : */
4018 172199 : if (list_length(f->fromlist) == 1 &&
4019 170514 : f != root->parse->jointree &&
4020 5435 : (f->quals == NULL || parent_quals != NULL))
4021 : {
4022 : /*
4023 : * Merge any quals up to parent. They should be in implicit-AND
4024 : * format by now, so we just need to concatenate lists. Put the
4025 : * child quals at the front, on the grounds that they should
4026 : * nominally be evaluated earlier.
4027 : */
4028 2268 : if (f->quals != NULL)
4029 1164 : *parent_quals = (Node *)
4030 1164 : list_concat(castNode(List, f->quals),
4031 : castNode(List, *parent_quals));
4032 2268 : return (Node *) linitial(f->fromlist);
4033 : }
4034 : }
4035 48073 : else if (IsA(jtnode, JoinExpr))
4036 : {
4037 48073 : JoinExpr *j = (JoinExpr *) jtnode;
4038 : int varno;
4039 :
4040 : /*
4041 : * First, recurse. We can absorb pushed-up FromExpr quals from either
4042 : * child into this node if the jointype is INNER, since then this is
4043 : * equivalent to a FromExpr. When the jointype is LEFT, we can absorb
4044 : * quals from the RHS child into the current node, as they're
4045 : * essentially degenerate quals of the outer join. Moreover, if we've
4046 : * been passed down a parent_quals pointer then we can allow quals of
4047 : * the LHS child to be absorbed into the parent. (This is important
4048 : * to ensure we remove single-child FromExprs immediately below
4049 : * commutable left joins.) For other jointypes, we can't move child
4050 : * quals up, or at least there's no particular reason to.
4051 : */
4052 48073 : j->larg = remove_useless_results_recurse(root, j->larg,
4053 48073 : (j->jointype == JOIN_INNER) ?
4054 : &j->quals :
4055 37681 : (j->jointype == JOIN_LEFT) ?
4056 37681 : parent_quals : NULL,
4057 : dropped_outer_joins);
4058 48073 : j->rarg = remove_useless_results_recurse(root, j->rarg,
4059 48073 : (j->jointype == JOIN_INNER ||
4060 37681 : j->jointype == JOIN_LEFT) ?
4061 : &j->quals : NULL,
4062 : dropped_outer_joins);
4063 :
4064 : /* Apply join-type-specific optimization rules */
4065 48073 : switch (j->jointype)
4066 : {
4067 10392 : case JOIN_INNER:
4068 :
4069 : /*
4070 : * An inner join is equivalent to a FromExpr, so if either
4071 : * side was simplified to an RTE_RESULT rel, we can replace
4072 : * the join with a FromExpr with just the other side.
4073 : * Furthermore, we can elide that FromExpr according to the
4074 : * same rules as above.
4075 : *
4076 : * Just as in the FromExpr case, we can't simplify if the
4077 : * other input rel references any PHVs that are marked as to
4078 : * be evaluated at the RTE_RESULT rel, because we can't
4079 : * postpone their evaluation in that case. But we only have
4080 : * to check this in cases where it's syntactically legal for
4081 : * the other input to have a LATERAL reference to the
4082 : * RTE_RESULT rel. Only RHSes of inner and left joins are
4083 : * allowed to have such refs.
4084 : */
4085 10392 : if ((varno = get_result_relid(root, j->larg)) != 0 &&
4086 83 : !find_dependent_phvs_in_jointree(root, j->rarg, varno))
4087 : {
4088 83 : remove_result_refs(root, varno, j->rarg);
4089 83 : if (j->quals != NULL && parent_quals == NULL)
4090 10 : jtnode = (Node *)
4091 10 : makeFromExpr(list_make1(j->rarg), j->quals);
4092 : else
4093 : {
4094 : /* Merge any quals up to parent */
4095 73 : if (j->quals != NULL)
4096 55 : *parent_quals = (Node *)
4097 55 : list_concat(castNode(List, j->quals),
4098 : castNode(List, *parent_quals));
4099 73 : jtnode = j->rarg;
4100 : }
4101 : }
4102 10309 : else if ((varno = get_result_relid(root, j->rarg)) != 0)
4103 : {
4104 565 : remove_result_refs(root, varno, j->larg);
4105 565 : if (j->quals != NULL && parent_quals == NULL)
4106 10 : jtnode = (Node *)
4107 10 : makeFromExpr(list_make1(j->larg), j->quals);
4108 : else
4109 : {
4110 : /* Merge any quals up to parent */
4111 555 : if (j->quals != NULL)
4112 394 : *parent_quals = (Node *)
4113 394 : list_concat(castNode(List, j->quals),
4114 : castNode(List, *parent_quals));
4115 555 : jtnode = j->larg;
4116 : }
4117 : }
4118 10392 : break;
4119 32963 : case JOIN_LEFT:
4120 :
4121 : /*
4122 : * We can simplify this case if the RHS is an RTE_RESULT, with
4123 : * two different possibilities:
4124 : *
4125 : * If the qual is empty (JOIN ON TRUE), then the join can be
4126 : * strength-reduced to a plain inner join, since each LHS row
4127 : * necessarily has exactly one join partner. So we can always
4128 : * discard the RHS, much as in the JOIN_INNER case above.
4129 : * (Again, the LHS could not contain a lateral reference to
4130 : * the RHS.)
4131 : *
4132 : * Otherwise, it's still true that each LHS row should be
4133 : * returned exactly once, and since the RHS returns no columns
4134 : * (unless there are PHVs that have to be evaluated there), we
4135 : * don't much care if it's null-extended or not. So in this
4136 : * case also, we can just ignore the qual and discard the left
4137 : * join.
4138 : */
4139 32963 : if ((varno = get_result_relid(root, j->rarg)) != 0 &&
4140 109 : (j->quals == NULL ||
4141 59 : !find_dependent_phvs(root, varno)))
4142 : {
4143 50 : remove_result_refs(root, varno, j->larg);
4144 50 : *dropped_outer_joins = bms_add_member(*dropped_outer_joins,
4145 : j->rtindex);
4146 50 : jtnode = j->larg;
4147 : }
4148 32963 : break;
4149 2710 : case JOIN_SEMI:
4150 :
4151 : /*
4152 : * We may simplify this case if the RHS is an RTE_RESULT; the
4153 : * join qual becomes effectively just a filter qual for the
4154 : * LHS, since we should either return the LHS row or not. The
4155 : * filter clause must go into a new FromExpr if we can't push
4156 : * it up to the parent.
4157 : *
4158 : * There is a fine point about PHVs that are supposed to be
4159 : * evaluated at the RHS. Such PHVs could only appear in the
4160 : * semijoin's qual, since the rest of the query cannot
4161 : * reference any outputs of the semijoin's RHS. Therefore,
4162 : * they can't actually go to null before being examined, and
4163 : * it'd be OK to just remove the PHV wrapping. We don't have
4164 : * infrastructure for that, but remove_result_refs() will
4165 : * relabel them as to be evaluated at the LHS, which is fine.
4166 : *
4167 : * Also, we don't need to worry about removing traces of the
4168 : * join's rtindex, since it hasn't got one.
4169 : */
4170 2710 : if ((varno = get_result_relid(root, j->rarg)) != 0)
4171 : {
4172 : Assert(j->rtindex == 0);
4173 30 : remove_result_refs(root, varno, j->larg);
4174 30 : if (j->quals != NULL && parent_quals == NULL)
4175 0 : jtnode = (Node *)
4176 0 : makeFromExpr(list_make1(j->larg), j->quals);
4177 : else
4178 : {
4179 : /* Merge any quals up to parent */
4180 30 : if (j->quals != NULL)
4181 30 : *parent_quals = (Node *)
4182 30 : list_concat(castNode(List, j->quals),
4183 : castNode(List, *parent_quals));
4184 30 : jtnode = j->larg;
4185 : }
4186 : }
4187 2710 : break;
4188 2008 : case JOIN_FULL:
4189 : case JOIN_ANTI:
4190 : /* We have no special smarts for these cases */
4191 2008 : break;
4192 0 : default:
4193 : /* Note: JOIN_RIGHT should be gone at this point */
4194 0 : elog(ERROR, "unrecognized join type: %d",
4195 : (int) j->jointype);
4196 : break;
4197 : }
4198 : }
4199 : else
4200 0 : elog(ERROR, "unrecognized node type: %d",
4201 : (int) nodeTag(jtnode));
4202 435667 : return jtnode;
4203 : }
4204 :
4205 : /*
4206 : * get_result_relid
4207 : * If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
4208 : * otherwise return 0.
4209 : */
4210 : static int
4211 61248 : get_result_relid(PlannerInfo *root, Node *jtnode)
4212 : {
4213 : int varno;
4214 :
4215 61248 : if (!IsA(jtnode, RangeTblRef))
4216 6363 : return 0;
4217 54885 : varno = ((RangeTblRef *) jtnode)->rtindex;
4218 54885 : if (rt_fetch(varno, root->parse->rtable)->rtekind != RTE_RESULT)
4219 53820 : return 0;
4220 1065 : return varno;
4221 : }
4222 :
4223 : /*
4224 : * remove_result_refs
4225 : * Helper routine for dropping an unneeded RTE_RESULT RTE.
4226 : *
4227 : * This doesn't physically remove the RTE from the jointree, because that's
4228 : * more easily handled in remove_useless_results_recurse. What it does do
4229 : * is the necessary cleanup in the rest of the tree: we must adjust any PHVs
4230 : * that may reference the RTE. Be sure to call this at a point where the
4231 : * jointree is valid (no disconnected nodes).
4232 : *
4233 : * Note that we don't need to process the append_rel_list, since RTEs
4234 : * referenced directly in the jointree won't be appendrel members.
4235 : *
4236 : * varno is the RTE_RESULT's relid.
4237 : * newjtloc is the jointree location at which any PHVs referencing the
4238 : * RTE_RESULT should be evaluated instead.
4239 : */
4240 : static void
4241 986 : remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc)
4242 : {
4243 : /* Fix up PlaceHolderVars as needed */
4244 : /* If there are no PHVs anywhere, we can skip this bit */
4245 986 : if (root->glob->lastPHId != 0)
4246 : {
4247 : Relids subrelids;
4248 :
4249 198 : subrelids = get_relids_in_jointree(newjtloc, true, false);
4250 : Assert(!bms_is_empty(subrelids));
4251 198 : substitute_phv_relids((Node *) root->parse, varno, subrelids);
4252 198 : fix_append_rel_relids(root, varno, subrelids);
4253 : }
4254 :
4255 : /*
4256 : * We also need to remove any PlanRowMark referencing the RTE, but we
4257 : * postpone that work until we return to remove_useless_result_rtes.
4258 : */
4259 986 : }
4260 :
4261 :
4262 : /*
4263 : * find_dependent_phvs - are there any PlaceHolderVars whose relids are
4264 : * exactly the given varno?
4265 : *
4266 : * find_dependent_phvs should be used when we want to see if there are
4267 : * any such PHVs anywhere in the Query. Another use-case is to see if
4268 : * a subtree of the join tree contains such PHVs; but for that, we have
4269 : * to look not only at the join tree nodes themselves but at the
4270 : * referenced RTEs. For that, use find_dependent_phvs_in_jointree.
4271 : */
4272 :
4273 : typedef struct
4274 : {
4275 : Relids relids;
4276 : int sublevels_up;
4277 : } find_dependent_phvs_context;
4278 :
4279 : static bool
4280 1678 : find_dependent_phvs_walker(Node *node,
4281 : find_dependent_phvs_context *context)
4282 : {
4283 1678 : if (node == NULL)
4284 400 : return false;
4285 1278 : if (IsA(node, PlaceHolderVar))
4286 : {
4287 114 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4288 :
4289 228 : if (phv->phlevelsup == context->sublevels_up &&
4290 114 : bms_equal(context->relids, phv->phrels))
4291 79 : return true;
4292 : /* fall through to examine children */
4293 : }
4294 1199 : if (IsA(node, Query))
4295 : {
4296 : /* Recurse into subselects */
4297 : bool result;
4298 :
4299 40 : context->sublevels_up++;
4300 40 : result = query_tree_walker((Query *) node,
4301 : find_dependent_phvs_walker,
4302 : context, 0);
4303 40 : context->sublevels_up--;
4304 40 : return result;
4305 : }
4306 : /* Shouldn't need to handle most planner auxiliary nodes here */
4307 : Assert(!IsA(node, SpecialJoinInfo));
4308 : Assert(!IsA(node, PlaceHolderInfo));
4309 : Assert(!IsA(node, MinMaxAggInfo));
4310 :
4311 1159 : return expression_tree_walker(node, find_dependent_phvs_walker, context);
4312 : }
4313 :
4314 : static bool
4315 59 : find_dependent_phvs(PlannerInfo *root, int varno)
4316 : {
4317 : find_dependent_phvs_context context;
4318 :
4319 : /* If there are no PHVs anywhere, we needn't work hard */
4320 59 : if (root->glob->lastPHId == 0)
4321 0 : return false;
4322 :
4323 59 : context.relids = bms_make_singleton(varno);
4324 59 : context.sublevels_up = 0;
4325 :
4326 59 : if (query_tree_walker(root->parse, find_dependent_phvs_walker, &context, 0))
4327 59 : return true;
4328 : /* The append_rel_list could be populated already, so check it too */
4329 0 : if (expression_tree_walker((Node *) root->append_rel_list,
4330 : find_dependent_phvs_walker,
4331 : &context))
4332 0 : return true;
4333 0 : return false;
4334 : }
4335 :
4336 : static bool
4337 361 : find_dependent_phvs_in_jointree(PlannerInfo *root, Node *node, int varno)
4338 : {
4339 : find_dependent_phvs_context context;
4340 : Relids subrelids;
4341 : int relid;
4342 :
4343 : /* If there are no PHVs anywhere, we needn't work hard */
4344 361 : if (root->glob->lastPHId == 0)
4345 306 : return false;
4346 :
4347 55 : context.relids = bms_make_singleton(varno);
4348 55 : context.sublevels_up = 0;
4349 :
4350 : /*
4351 : * See if the jointree fragment itself contains references (in join quals)
4352 : */
4353 55 : if (find_dependent_phvs_walker(node, &context))
4354 0 : return true;
4355 :
4356 : /*
4357 : * Otherwise, identify the set of referenced RTEs (we can ignore joins,
4358 : * since they should be flattened already, so their join alias lists no
4359 : * longer matter), and tediously check each RTE. We can ignore RTEs that
4360 : * are not marked LATERAL, though, since they couldn't possibly contain
4361 : * any cross-references to other RTEs.
4362 : */
4363 55 : subrelids = get_relids_in_jointree(node, false, false);
4364 55 : relid = -1;
4365 120 : while ((relid = bms_next_member(subrelids, relid)) >= 0)
4366 : {
4367 85 : RangeTblEntry *rte = rt_fetch(relid, root->parse->rtable);
4368 :
4369 105 : if (rte->lateral &&
4370 20 : range_table_entry_walker(rte, find_dependent_phvs_walker, &context, 0))
4371 20 : return true;
4372 : }
4373 :
4374 35 : return false;
4375 : }
4376 :
4377 : /*
4378 : * substitute_phv_relids - adjust PlaceHolderVar relid sets after pulling up
4379 : * a subquery or removing an RTE_RESULT jointree item
4380 : *
4381 : * Find any PlaceHolderVar nodes in the given tree that reference the
4382 : * pulled-up relid, and change them to reference the replacement relid(s).
4383 : *
4384 : * NOTE: although this has the form of a walker, we cheat and modify the
4385 : * nodes in-place. This should be OK since the tree was copied by
4386 : * pullup_replace_vars earlier. Avoid scribbling on the original values of
4387 : * the bitmapsets, though, because expression_tree_mutator doesn't copy those.
4388 : */
4389 :
4390 : typedef struct
4391 : {
4392 : int varno;
4393 : int sublevels_up;
4394 : Relids subrelids;
4395 : } substitute_phv_relids_context;
4396 :
4397 : static bool
4398 215704 : substitute_phv_relids_walker(Node *node,
4399 : substitute_phv_relids_context *context)
4400 : {
4401 215704 : if (node == NULL)
4402 83382 : return false;
4403 132322 : if (IsA(node, PlaceHolderVar))
4404 : {
4405 6364 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4406 :
4407 12704 : if (phv->phlevelsup == context->sublevels_up &&
4408 6340 : bms_is_member(context->varno, phv->phrels))
4409 : {
4410 9160 : phv->phrels = bms_union(phv->phrels,
4411 4580 : context->subrelids);
4412 4580 : phv->phrels = bms_del_member(phv->phrels,
4413 : context->varno);
4414 : /* Assert we haven't broken the PHV */
4415 : Assert(!bms_is_empty(phv->phrels));
4416 : }
4417 : /* fall through to examine children */
4418 : }
4419 132322 : if (IsA(node, Query))
4420 : {
4421 : /* Recurse into subselects */
4422 : bool result;
4423 :
4424 3598 : context->sublevels_up++;
4425 3598 : result = query_tree_walker((Query *) node,
4426 : substitute_phv_relids_walker,
4427 : context, 0);
4428 3598 : context->sublevels_up--;
4429 3598 : return result;
4430 : }
4431 : /* Shouldn't need to handle planner auxiliary nodes here */
4432 : Assert(!IsA(node, SpecialJoinInfo));
4433 : Assert(!IsA(node, AppendRelInfo));
4434 : Assert(!IsA(node, PlaceHolderInfo));
4435 : Assert(!IsA(node, MinMaxAggInfo));
4436 :
4437 128724 : return expression_tree_walker(node, substitute_phv_relids_walker, context);
4438 : }
4439 :
4440 : static void
4441 2005 : substitute_phv_relids(Node *node, int varno, Relids subrelids)
4442 : {
4443 : substitute_phv_relids_context context;
4444 :
4445 2005 : context.varno = varno;
4446 2005 : context.sublevels_up = 0;
4447 2005 : context.subrelids = subrelids;
4448 :
4449 : /*
4450 : * Must be prepared to start with a Query or a bare expression tree.
4451 : */
4452 2005 : query_or_expression_tree_walker(node,
4453 : substitute_phv_relids_walker,
4454 : &context,
4455 : 0);
4456 2005 : }
4457 :
4458 : /*
4459 : * fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
4460 : *
4461 : * When we pull up a subquery, any AppendRelInfo references to the subquery's
4462 : * RT index have to be replaced by the substituted relid (and there had better
4463 : * be only one). We also need to apply substitute_phv_relids to their
4464 : * translated_vars lists, since those might contain PlaceHolderVars.
4465 : *
4466 : * We assume we may modify the AppendRelInfo nodes in-place.
4467 : */
4468 : static void
4469 6941 : fix_append_rel_relids(PlannerInfo *root, int varno, Relids subrelids)
4470 : {
4471 : ListCell *l;
4472 6941 : int subvarno = -1;
4473 :
4474 : /*
4475 : * We only want to extract the member relid once, but we mustn't fail
4476 : * immediately if there are multiple members; it could be that none of the
4477 : * AppendRelInfo nodes refer to it. So compute it on first use. Note that
4478 : * bms_singleton_member will complain if set is not singleton.
4479 : */
4480 16474 : foreach(l, root->append_rel_list)
4481 : {
4482 9533 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
4483 :
4484 : /* The parent_relid shouldn't ever be a pullup target */
4485 : Assert(appinfo->parent_relid != varno);
4486 :
4487 9533 : if (appinfo->child_relid == varno)
4488 : {
4489 5101 : if (subvarno < 0)
4490 5101 : subvarno = bms_singleton_member(subrelids);
4491 5101 : appinfo->child_relid = subvarno;
4492 : }
4493 :
4494 : /* Also fix up any PHVs in its translated vars */
4495 9533 : if (root->glob->lastPHId != 0)
4496 135 : substitute_phv_relids((Node *) appinfo->translated_vars,
4497 : varno, subrelids);
4498 : }
4499 6941 : }
4500 :
4501 : /*
4502 : * get_relids_in_jointree: get set of RT indexes present in a jointree
4503 : *
4504 : * Base-relation relids are always included in the result.
4505 : * If include_outer_joins is true, outer-join RT indexes are included.
4506 : * If include_inner_joins is true, inner-join RT indexes are included.
4507 : *
4508 : * Note that for most purposes in the planner, outer joins are included
4509 : * in standard relid sets. Setting include_inner_joins true is only
4510 : * appropriate for special purposes during subquery flattening.
4511 : */
4512 : Relids
4513 76665 : get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
4514 : bool include_inner_joins)
4515 : {
4516 76665 : Relids result = NULL;
4517 :
4518 76665 : if (jtnode == NULL)
4519 0 : return result;
4520 76665 : if (IsA(jtnode, RangeTblRef))
4521 : {
4522 38862 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4523 :
4524 38862 : result = bms_make_singleton(varno);
4525 : }
4526 37803 : else if (IsA(jtnode, FromExpr))
4527 : {
4528 33120 : FromExpr *f = (FromExpr *) jtnode;
4529 : ListCell *l;
4530 :
4531 67760 : foreach(l, f->fromlist)
4532 : {
4533 34640 : result = bms_join(result,
4534 34640 : get_relids_in_jointree(lfirst(l),
4535 : include_outer_joins,
4536 : include_inner_joins));
4537 : }
4538 : }
4539 4683 : else if (IsA(jtnode, JoinExpr))
4540 : {
4541 4683 : JoinExpr *j = (JoinExpr *) jtnode;
4542 :
4543 4683 : result = get_relids_in_jointree(j->larg,
4544 : include_outer_joins,
4545 : include_inner_joins);
4546 4683 : result = bms_join(result,
4547 : get_relids_in_jointree(j->rarg,
4548 : include_outer_joins,
4549 : include_inner_joins));
4550 4683 : if (j->rtindex)
4551 : {
4552 4424 : if (j->jointype == JOIN_INNER)
4553 : {
4554 1841 : if (include_inner_joins)
4555 635 : result = bms_add_member(result, j->rtindex);
4556 : }
4557 : else
4558 : {
4559 2583 : if (include_outer_joins)
4560 1661 : result = bms_add_member(result, j->rtindex);
4561 : }
4562 : }
4563 : }
4564 : else
4565 0 : elog(ERROR, "unrecognized node type: %d",
4566 : (int) nodeTag(jtnode));
4567 76665 : return result;
4568 : }
4569 :
4570 : /*
4571 : * get_relids_for_join: get set of base+OJ RT indexes making up a join
4572 : */
4573 : Relids
4574 297 : get_relids_for_join(Query *query, int joinrelid)
4575 : {
4576 : Node *jtnode;
4577 :
4578 297 : jtnode = find_jointree_node_for_rel((Node *) query->jointree,
4579 : joinrelid);
4580 297 : if (!jtnode)
4581 0 : elog(ERROR, "could not find join node %d", joinrelid);
4582 297 : return get_relids_in_jointree(jtnode, true, false);
4583 : }
4584 :
4585 : /*
4586 : * find_jointree_node_for_rel: locate jointree node for a base or join RT index
4587 : *
4588 : * Returns NULL if not found
4589 : */
4590 : static Node *
4591 1435 : find_jointree_node_for_rel(Node *jtnode, int relid)
4592 : {
4593 1435 : if (jtnode == NULL)
4594 0 : return NULL;
4595 1435 : if (IsA(jtnode, RangeTblRef))
4596 : {
4597 377 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4598 :
4599 377 : if (relid == varno)
4600 0 : return jtnode;
4601 : }
4602 1058 : else if (IsA(jtnode, FromExpr))
4603 : {
4604 304 : FromExpr *f = (FromExpr *) jtnode;
4605 : ListCell *l;
4606 :
4607 319 : foreach(l, f->fromlist)
4608 : {
4609 319 : jtnode = find_jointree_node_for_rel(lfirst(l), relid);
4610 319 : if (jtnode)
4611 304 : return jtnode;
4612 : }
4613 : }
4614 754 : else if (IsA(jtnode, JoinExpr))
4615 : {
4616 754 : JoinExpr *j = (JoinExpr *) jtnode;
4617 :
4618 754 : if (relid == j->rtindex)
4619 297 : return jtnode;
4620 457 : jtnode = find_jointree_node_for_rel(j->larg, relid);
4621 457 : if (jtnode)
4622 95 : return jtnode;
4623 362 : jtnode = find_jointree_node_for_rel(j->rarg, relid);
4624 362 : if (jtnode)
4625 362 : return jtnode;
4626 : }
4627 : else
4628 0 : elog(ERROR, "unrecognized node type: %d",
4629 : (int) nodeTag(jtnode));
4630 377 : return NULL;
4631 : }
4632 :
4633 : /*
4634 : * get_nullingrels: collect info about which outer joins null which relations
4635 : *
4636 : * The result struct contains, for each leaf relation used in the query,
4637 : * the set of relids of outer joins that potentially null that rel.
4638 : */
4639 : static nullingrel_info *
4640 1339 : get_nullingrels(Query *parse)
4641 : {
4642 1339 : nullingrel_info *result = palloc_object(nullingrel_info);
4643 :
4644 1339 : result->rtlength = list_length(parse->rtable);
4645 1339 : result->nullingrels = palloc0_array(Relids, result->rtlength + 1);
4646 1339 : get_nullingrels_recurse((Node *) parse->jointree, NULL, result);
4647 1339 : return result;
4648 : }
4649 :
4650 : /*
4651 : * Recursive guts of get_nullingrels().
4652 : *
4653 : * Note: at any recursion level, the passed-down upper_nullingrels must be
4654 : * treated as a constant, but it can be stored directly into *info
4655 : * if we're at leaf level. Upper recursion levels do not free their mutated
4656 : * copies of the nullingrels, because those are probably referenced by
4657 : * at least one leaf rel.
4658 : */
4659 : static void
4660 5549 : get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
4661 : nullingrel_info *info)
4662 : {
4663 5549 : if (jtnode == NULL)
4664 0 : return;
4665 5549 : if (IsA(jtnode, RangeTblRef))
4666 : {
4667 2929 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4668 :
4669 : Assert(varno > 0 && varno <= info->rtlength);
4670 2929 : info->nullingrels[varno] = upper_nullingrels;
4671 : }
4672 2620 : else if (IsA(jtnode, FromExpr))
4673 : {
4674 1409 : FromExpr *f = (FromExpr *) jtnode;
4675 : ListCell *l;
4676 :
4677 3197 : foreach(l, f->fromlist)
4678 : {
4679 1788 : get_nullingrels_recurse(lfirst(l), upper_nullingrels, info);
4680 : }
4681 : }
4682 1211 : else if (IsA(jtnode, JoinExpr))
4683 : {
4684 1211 : JoinExpr *j = (JoinExpr *) jtnode;
4685 : Relids local_nullingrels;
4686 :
4687 1211 : switch (j->jointype)
4688 : {
4689 395 : case JOIN_INNER:
4690 395 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4691 395 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4692 395 : break;
4693 811 : case JOIN_LEFT:
4694 : case JOIN_SEMI:
4695 : case JOIN_ANTI:
4696 811 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4697 : j->rtindex);
4698 811 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4699 811 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4700 811 : break;
4701 5 : case JOIN_FULL:
4702 5 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4703 : j->rtindex);
4704 5 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4705 5 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4706 5 : break;
4707 0 : case JOIN_RIGHT:
4708 0 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4709 : j->rtindex);
4710 0 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4711 0 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4712 0 : break;
4713 0 : default:
4714 0 : elog(ERROR, "unrecognized join type: %d",
4715 : (int) j->jointype);
4716 : break;
4717 : }
4718 : }
4719 : else
4720 0 : elog(ERROR, "unrecognized node type: %d",
4721 : (int) nodeTag(jtnode));
4722 : }
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