Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * prepjointree.c
4 : * Planner preprocessing for subqueries and join tree manipulation.
5 : *
6 : * NOTE: the intended sequence for invoking these operations is
7 : * preprocess_relation_rtes
8 : * replace_empty_jointree
9 : * pull_up_sublinks
10 : * preprocess_function_rtes
11 : * pull_up_subqueries
12 : * flatten_simple_union_all
13 : * do expression preprocessing (including flattening JOIN alias vars)
14 : * reduce_outer_joins
15 : * remove_useless_result_rtes
16 : *
17 : *
18 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
19 : * Portions Copyright (c) 1994, Regents of the University of California
20 : *
21 : *
22 : * IDENTIFICATION
23 : * src/backend/optimizer/prep/prepjointree.c
24 : *
25 : *-------------------------------------------------------------------------
26 : */
27 : #include "postgres.h"
28 :
29 : #include "access/table.h"
30 : #include "catalog/pg_type.h"
31 : #include "funcapi.h"
32 : #include "miscadmin.h"
33 : #include "nodes/makefuncs.h"
34 : #include "nodes/multibitmapset.h"
35 : #include "nodes/nodeFuncs.h"
36 : #include "optimizer/clauses.h"
37 : #include "optimizer/optimizer.h"
38 : #include "optimizer/placeholder.h"
39 : #include "optimizer/plancat.h"
40 : #include "optimizer/prep.h"
41 : #include "optimizer/subselect.h"
42 : #include "optimizer/tlist.h"
43 : #include "parser/parse_relation.h"
44 : #include "parser/parsetree.h"
45 : #include "rewrite/rewriteHandler.h"
46 : #include "rewrite/rewriteManip.h"
47 : #include "utils/rel.h"
48 :
49 :
50 : typedef struct nullingrel_info
51 : {
52 : /*
53 : * For each leaf RTE, nullingrels[rti] is the set of relids of outer joins
54 : * that potentially null that RTE.
55 : */
56 : Relids *nullingrels;
57 : /* Length of range table (maximum index in nullingrels[]) */
58 : int rtlength; /* used only for assertion checks */
59 : } nullingrel_info;
60 :
61 : /* Options for wrapping an expression for identification purposes */
62 : typedef enum ReplaceWrapOption
63 : {
64 : REPLACE_WRAP_NONE, /* no expressions need to be wrapped */
65 : REPLACE_WRAP_ALL, /* all expressions need to be wrapped */
66 : REPLACE_WRAP_VARFREE, /* variable-free expressions need to be
67 : * wrapped */
68 : } ReplaceWrapOption;
69 :
70 : typedef struct pullup_replace_vars_context
71 : {
72 : PlannerInfo *root;
73 : List *targetlist; /* tlist of subquery being pulled up */
74 : RangeTblEntry *target_rte; /* RTE of subquery */
75 : int result_relation; /* the index of the result relation in the
76 : * rewritten query */
77 : Relids relids; /* relids within subquery, as numbered after
78 : * pullup (set only if target_rte->lateral) */
79 : nullingrel_info *nullinfo; /* per-RTE nullingrel info (set only if
80 : * target_rte->lateral) */
81 : bool *outer_hasSubLinks; /* -> outer query's hasSubLinks */
82 : int varno; /* varno of subquery */
83 : ReplaceWrapOption wrap_option; /* do we need certain outputs to be PHVs? */
84 : Node **rv_cache; /* cache for results with PHVs */
85 : } pullup_replace_vars_context;
86 :
87 : typedef struct reduce_outer_joins_pass1_state
88 : {
89 : Relids relids; /* base relids within this subtree */
90 : bool contains_outer; /* does subtree contain outer join(s)? */
91 : List *sub_states; /* List of states for subtree components */
92 : } reduce_outer_joins_pass1_state;
93 :
94 : typedef struct reduce_outer_joins_pass2_state
95 : {
96 : Relids inner_reduced; /* OJ relids reduced to plain inner joins */
97 : List *partial_reduced; /* List of partially reduced FULL joins */
98 : } reduce_outer_joins_pass2_state;
99 :
100 : typedef struct reduce_outer_joins_partial_state
101 : {
102 : int full_join_rti; /* RT index of a formerly-FULL join */
103 : Relids unreduced_side; /* relids in its still-nullable side */
104 : } reduce_outer_joins_partial_state;
105 :
106 : static Query *expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
107 : RangeTblEntry *rte, int rt_index,
108 : Relation relation);
109 : static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
110 : Relids *relids);
111 : static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
112 : Node **jtlink1, Relids available_rels1,
113 : Node **jtlink2, Relids available_rels2);
114 : static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
115 : JoinExpr *lowest_outer_join,
116 : AppendRelInfo *containing_appendrel);
117 : static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
118 : RangeTblEntry *rte,
119 : JoinExpr *lowest_outer_join,
120 : AppendRelInfo *containing_appendrel);
121 : static Node *pull_up_simple_union_all(PlannerInfo *root, Node *jtnode,
122 : RangeTblEntry *rte);
123 : static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
124 : int parentRTindex, Query *setOpQuery,
125 : int childRToffset);
126 : static void make_setop_translation_list(Query *query, int newvarno,
127 : AppendRelInfo *appinfo);
128 : static bool is_simple_subquery(PlannerInfo *root, Query *subquery,
129 : RangeTblEntry *rte,
130 : JoinExpr *lowest_outer_join);
131 : static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
132 : RangeTblEntry *rte);
133 : static bool is_simple_values(PlannerInfo *root, RangeTblEntry *rte);
134 : static Node *pull_up_constant_function(PlannerInfo *root, Node *jtnode,
135 : RangeTblEntry *rte,
136 : AppendRelInfo *containing_appendrel);
137 : static bool is_simple_union_all(Query *subquery);
138 : static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery,
139 : List *colTypes);
140 : static bool is_safe_append_member(Query *subquery);
141 : static bool jointree_contains_lateral_outer_refs(PlannerInfo *root,
142 : Node *jtnode, bool restricted,
143 : Relids safe_upper_varnos);
144 : static void perform_pullup_replace_vars(PlannerInfo *root,
145 : pullup_replace_vars_context *rvcontext,
146 : AppendRelInfo *containing_appendrel);
147 : static void replace_vars_in_jointree(Node *jtnode,
148 : pullup_replace_vars_context *context);
149 : static Node *pullup_replace_vars(Node *expr,
150 : pullup_replace_vars_context *context);
151 : static Node *pullup_replace_vars_callback(Var *var,
152 : replace_rte_variables_context *context);
153 : static Query *pullup_replace_vars_subquery(Query *query,
154 : pullup_replace_vars_context *context);
155 : static reduce_outer_joins_pass1_state *reduce_outer_joins_pass1(Node *jtnode);
156 : static void reduce_outer_joins_pass2(Node *jtnode,
157 : reduce_outer_joins_pass1_state *state1,
158 : reduce_outer_joins_pass2_state *state2,
159 : PlannerInfo *root,
160 : Relids nonnullable_rels,
161 : List *forced_null_vars);
162 : static void report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
163 : int rtindex, Relids relids);
164 : static Node *remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
165 : Node **parent_quals,
166 : Relids *dropped_outer_joins);
167 : static int get_result_relid(PlannerInfo *root, Node *jtnode);
168 : static void remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc);
169 : static bool find_dependent_phvs(PlannerInfo *root, int varno);
170 : static bool find_dependent_phvs_in_jointree(PlannerInfo *root,
171 : Node *node, int varno);
172 : static void substitute_phv_relids(Node *node,
173 : int varno, Relids subrelids);
174 : static void fix_append_rel_relids(PlannerInfo *root, int varno,
175 : Relids subrelids);
176 : static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
177 : static nullingrel_info *get_nullingrels(Query *parse);
178 : static void get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
179 : nullingrel_info *info);
180 :
181 :
182 : /*
183 : * transform_MERGE_to_join
184 : * Replace a MERGE's jointree to also include the target relation.
185 : */
186 : void
187 530368 : transform_MERGE_to_join(Query *parse)
188 : {
189 : RangeTblEntry *joinrte;
190 : JoinExpr *joinexpr;
191 : bool have_action[NUM_MERGE_MATCH_KINDS];
192 : JoinType jointype;
193 : int joinrti;
194 : List *vars;
195 : RangeTblRef *rtr;
196 : FromExpr *target;
197 : Node *source;
198 : int sourcerti;
199 :
200 530368 : if (parse->commandType != CMD_MERGE)
201 528406 : return;
202 :
203 : /* XXX probably bogus */
204 1962 : vars = NIL;
205 :
206 : /*
207 : * Work out what kind of join is required. If there any WHEN NOT MATCHED
208 : * BY SOURCE/TARGET actions, an outer join is required so that we process
209 : * all unmatched tuples from the source and/or target relations.
210 : * Otherwise, we can use an inner join.
211 : */
212 1962 : have_action[MERGE_WHEN_MATCHED] = false;
213 1962 : have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = false;
214 1962 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = false;
215 :
216 6912 : foreach_node(MergeAction, action, parse->mergeActionList)
217 : {
218 2988 : if (action->commandType != CMD_NOTHING)
219 2904 : have_action[action->matchKind] = true;
220 : }
221 :
222 1962 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] &&
223 132 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
224 102 : jointype = JOIN_FULL;
225 1860 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
226 30 : jointype = JOIN_LEFT;
227 1830 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
228 848 : jointype = JOIN_RIGHT;
229 : else
230 982 : jointype = JOIN_INNER;
231 :
232 : /* Manufacture a join RTE to use. */
233 1962 : joinrte = makeNode(RangeTblEntry);
234 1962 : joinrte->rtekind = RTE_JOIN;
235 1962 : joinrte->jointype = jointype;
236 1962 : joinrte->joinmergedcols = 0;
237 1962 : joinrte->joinaliasvars = vars;
238 1962 : joinrte->joinleftcols = NIL; /* MERGE does not allow JOIN USING */
239 1962 : joinrte->joinrightcols = NIL; /* ditto */
240 1962 : joinrte->join_using_alias = NULL;
241 :
242 1962 : joinrte->alias = NULL;
243 1962 : joinrte->eref = makeAlias("*MERGE*", NIL);
244 1962 : joinrte->lateral = false;
245 1962 : joinrte->inh = false;
246 1962 : joinrte->inFromCl = true;
247 :
248 : /*
249 : * Add completed RTE to pstate's range table list, so that we know its
250 : * index.
251 : */
252 1962 : parse->rtable = lappend(parse->rtable, joinrte);
253 1962 : joinrti = list_length(parse->rtable);
254 :
255 : /*
256 : * Create a JOIN between the target and the source relation.
257 : *
258 : * Here the target is identified by parse->mergeTargetRelation. For a
259 : * regular table, this will equal parse->resultRelation, but for a
260 : * trigger-updatable view, it will be the expanded view subquery that we
261 : * need to pull data from.
262 : *
263 : * The source relation is in parse->jointree->fromlist, but any quals in
264 : * parse->jointree->quals are restrictions on the target relation (if the
265 : * target relation is an auto-updatable view).
266 : */
267 : /* target rel, with any quals */
268 1962 : rtr = makeNode(RangeTblRef);
269 1962 : rtr->rtindex = parse->mergeTargetRelation;
270 1962 : target = makeFromExpr(list_make1(rtr), parse->jointree->quals);
271 :
272 : /* source rel (expect exactly one -- see transformMergeStmt()) */
273 : Assert(list_length(parse->jointree->fromlist) == 1);
274 1962 : source = linitial(parse->jointree->fromlist);
275 :
276 : /*
277 : * index of source rel (expect either a RangeTblRef or a JoinExpr -- see
278 : * transformFromClauseItem()).
279 : */
280 1962 : if (IsA(source, RangeTblRef))
281 1878 : sourcerti = ((RangeTblRef *) source)->rtindex;
282 84 : else if (IsA(source, JoinExpr))
283 84 : sourcerti = ((JoinExpr *) source)->rtindex;
284 : else
285 : {
286 0 : elog(ERROR, "unrecognized source node type: %d",
287 : (int) nodeTag(source));
288 : sourcerti = 0; /* keep compiler quiet */
289 : }
290 :
291 : /* Join the source and target */
292 1962 : joinexpr = makeNode(JoinExpr);
293 1962 : joinexpr->jointype = jointype;
294 1962 : joinexpr->isNatural = false;
295 1962 : joinexpr->larg = (Node *) target;
296 1962 : joinexpr->rarg = source;
297 1962 : joinexpr->usingClause = NIL;
298 1962 : joinexpr->join_using_alias = NULL;
299 1962 : joinexpr->quals = parse->mergeJoinCondition;
300 1962 : joinexpr->alias = NULL;
301 1962 : joinexpr->rtindex = joinrti;
302 :
303 : /* Make the new join be the sole entry in the query's jointree */
304 1962 : parse->jointree->fromlist = list_make1(joinexpr);
305 1962 : parse->jointree->quals = NULL;
306 :
307 : /*
308 : * If necessary, mark parse->targetlist entries that refer to the target
309 : * as nullable by the join. Normally the targetlist will be empty for a
310 : * MERGE, but if the target is a trigger-updatable view, it will contain a
311 : * whole-row Var referring to the expanded view query.
312 : */
313 1962 : if (parse->targetList != NIL &&
314 42 : (jointype == JOIN_RIGHT || jointype == JOIN_FULL))
315 42 : parse->targetList = (List *)
316 42 : add_nulling_relids((Node *) parse->targetList,
317 42 : bms_make_singleton(parse->mergeTargetRelation),
318 42 : bms_make_singleton(joinrti));
319 :
320 : /*
321 : * If the source relation is on the outer side of the join, mark any
322 : * source relation Vars in the join condition, actions, and RETURNING list
323 : * as nullable by the join. These Vars will be added to the targetlist by
324 : * preprocess_targetlist(), so it's important to mark them correctly here.
325 : *
326 : * It might seem that this is not necessary for Vars in the join
327 : * condition, since it is inside the join, but it is also needed above the
328 : * join (in the ModifyTable node) to distinguish between the MATCHED and
329 : * NOT MATCHED BY SOURCE cases -- see ExecMergeMatched(). Note that this
330 : * creates a modified copy of the join condition, for use above the join,
331 : * without modifying the original join condition, inside the join.
332 : */
333 1962 : if (jointype == JOIN_LEFT || jointype == JOIN_FULL)
334 : {
335 132 : parse->mergeJoinCondition =
336 132 : add_nulling_relids(parse->mergeJoinCondition,
337 132 : bms_make_singleton(sourcerti),
338 132 : bms_make_singleton(joinrti));
339 :
340 630 : foreach_node(MergeAction, action, parse->mergeActionList)
341 : {
342 366 : action->qual =
343 366 : add_nulling_relids(action->qual,
344 366 : bms_make_singleton(sourcerti),
345 366 : bms_make_singleton(joinrti));
346 :
347 366 : action->targetList = (List *)
348 366 : add_nulling_relids((Node *) action->targetList,
349 366 : bms_make_singleton(sourcerti),
350 366 : bms_make_singleton(joinrti));
351 : }
352 :
353 132 : parse->returningList = (List *)
354 132 : add_nulling_relids((Node *) parse->returningList,
355 132 : bms_make_singleton(sourcerti),
356 132 : bms_make_singleton(joinrti));
357 : }
358 :
359 : /*
360 : * If there are any WHEN NOT MATCHED BY SOURCE actions, the executor will
361 : * use the join condition to distinguish between MATCHED and NOT MATCHED
362 : * BY SOURCE cases. Otherwise, it's no longer needed, and we set it to
363 : * NULL, saving cycles during planning and execution.
364 : *
365 : * We need to be careful though: the executor evaluates this condition
366 : * using the output of the join subplan node, which nulls the output from
367 : * the source relation when the join condition doesn't match. That risks
368 : * producing incorrect results when rechecking using a "non-strict" join
369 : * condition, such as "src.col IS NOT DISTINCT FROM tgt.col". To guard
370 : * against that, we add an additional "src IS NOT NULL" check to the join
371 : * condition, so that it does the right thing when performing a recheck
372 : * based on the output of the join subplan.
373 : */
374 1962 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
375 : {
376 : Var *var;
377 : NullTest *ntest;
378 :
379 : /* source wholerow Var (nullable by the new join) */
380 132 : var = makeWholeRowVar(rt_fetch(sourcerti, parse->rtable),
381 : sourcerti, 0, false);
382 132 : var->varnullingrels = bms_make_singleton(joinrti);
383 :
384 : /* "src IS NOT NULL" check */
385 132 : ntest = makeNode(NullTest);
386 132 : ntest->arg = (Expr *) var;
387 132 : ntest->nulltesttype = IS_NOT_NULL;
388 132 : ntest->argisrow = false;
389 132 : ntest->location = -1;
390 :
391 : /* combine it with the original join condition */
392 132 : parse->mergeJoinCondition =
393 132 : (Node *) make_and_qual((Node *) ntest, parse->mergeJoinCondition);
394 : }
395 : else
396 1830 : parse->mergeJoinCondition = NULL; /* join condition not needed */
397 : }
398 :
399 : /*
400 : * preprocess_relation_rtes
401 : * Do the preprocessing work for any relation RTEs in the FROM clause.
402 : *
403 : * This scans the rangetable for relation RTEs and retrieves the necessary
404 : * catalog information for each relation. Using this information, it clears
405 : * the inh flag for any relation that has no children, collects not-null
406 : * attribute numbers for any relation that has column not-null constraints, and
407 : * expands virtual generated columns for any relation that contains them.
408 : *
409 : * Note that expanding virtual generated columns may cause the query tree to
410 : * have new copies of rangetable entries. Therefore, we have to use list_nth
411 : * instead of foreach when iterating over the query's rangetable.
412 : *
413 : * Returns a modified copy of the query tree, if any relations with virtual
414 : * generated columns are present.
415 : */
416 : Query *
417 571876 : preprocess_relation_rtes(PlannerInfo *root)
418 : {
419 571876 : Query *parse = root->parse;
420 : int rtable_size;
421 : int rt_index;
422 :
423 571876 : rtable_size = list_length(parse->rtable);
424 :
425 1278268 : for (rt_index = 0; rt_index < rtable_size; rt_index++)
426 : {
427 706392 : RangeTblEntry *rte = rt_fetch(rt_index + 1, parse->rtable);
428 : Relation relation;
429 :
430 : /* We only care about relation RTEs. */
431 706392 : if (rte->rtekind != RTE_RELATION)
432 229304 : continue;
433 :
434 : /*
435 : * We need not lock the relation since it was already locked by the
436 : * rewriter.
437 : */
438 477088 : relation = table_open(rte->relid, NoLock);
439 :
440 : /*
441 : * Check to see if the relation actually has any children; if not,
442 : * clear the inh flag so we can treat it as a plain base relation.
443 : *
444 : * Note: this could give a false-positive result, if the rel once had
445 : * children but no longer does. We used to be able to clear rte->inh
446 : * later on when we discovered that, but no more; we have to handle
447 : * such cases as full-fledged inheritance.
448 : */
449 477088 : if (rte->inh)
450 393492 : rte->inh = relation->rd_rel->relhassubclass;
451 :
452 : /*
453 : * Check to see if the relation has any column not-null constraints;
454 : * if so, retrieve the constraint information and store it in a
455 : * relation OID based hash table.
456 : */
457 477088 : get_relation_notnullatts(root, relation);
458 :
459 : /*
460 : * Check to see if the relation has any virtual generated columns; if
461 : * so, replace all Var nodes in the query that reference these columns
462 : * with the generation expressions.
463 : */
464 477088 : parse = expand_virtual_generated_columns(root, parse,
465 : rte, rt_index + 1,
466 : relation);
467 :
468 477088 : table_close(relation, NoLock);
469 : }
470 :
471 571876 : return parse;
472 : }
473 :
474 : /*
475 : * expand_virtual_generated_columns
476 : * Expand virtual generated columns for the given relation.
477 : *
478 : * This checks whether the given relation has any virtual generated columns,
479 : * and if so, replaces all Var nodes in the query that reference those columns
480 : * with their generation expressions.
481 : *
482 : * Returns a modified copy of the query tree if the relation contains virtual
483 : * generated columns.
484 : */
485 : static Query *
486 477088 : expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
487 : RangeTblEntry *rte, int rt_index,
488 : Relation relation)
489 : {
490 : TupleDesc tupdesc;
491 :
492 : /* Only normal relations can have virtual generated columns */
493 : Assert(rte->rtekind == RTE_RELATION);
494 :
495 477088 : tupdesc = RelationGetDescr(relation);
496 477088 : if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
497 : {
498 1066 : List *tlist = NIL;
499 : pullup_replace_vars_context rvcontext;
500 :
501 4090 : for (int i = 0; i < tupdesc->natts; i++)
502 : {
503 3024 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
504 : TargetEntry *tle;
505 :
506 3024 : if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
507 : {
508 : Node *defexpr;
509 :
510 1408 : defexpr = build_generation_expression(relation, i + 1);
511 1408 : ChangeVarNodes(defexpr, 1, rt_index, 0);
512 :
513 1408 : tle = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
514 1408 : tlist = lappend(tlist, tle);
515 : }
516 : else
517 : {
518 : Var *var;
519 :
520 1616 : var = makeVar(rt_index,
521 1616 : i + 1,
522 : attr->atttypid,
523 : attr->atttypmod,
524 : attr->attcollation,
525 : 0);
526 :
527 1616 : tle = makeTargetEntry((Expr *) var, i + 1, 0, false);
528 1616 : tlist = lappend(tlist, tle);
529 : }
530 : }
531 :
532 : Assert(list_length(tlist) > 0);
533 : Assert(!rte->lateral);
534 :
535 : /*
536 : * The relation's targetlist items are now in the appropriate form to
537 : * insert into the query, except that we may need to wrap them in
538 : * PlaceHolderVars. Set up required context data for
539 : * pullup_replace_vars.
540 : */
541 1066 : rvcontext.root = root;
542 1066 : rvcontext.targetlist = tlist;
543 1066 : rvcontext.target_rte = rte;
544 1066 : rvcontext.result_relation = parse->resultRelation;
545 : /* won't need these values */
546 1066 : rvcontext.relids = NULL;
547 1066 : rvcontext.nullinfo = NULL;
548 : /* pass NULL for outer_hasSubLinks */
549 1066 : rvcontext.outer_hasSubLinks = NULL;
550 1066 : rvcontext.varno = rt_index;
551 : /* this flag will be set below, if needed */
552 1066 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
553 : /* initialize cache array with indexes 0 .. length(tlist) */
554 1066 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
555 : sizeof(Node *));
556 :
557 : /*
558 : * If the query uses grouping sets, we need a PlaceHolderVar for each
559 : * expression of the relation's targetlist items. (See comments in
560 : * pull_up_simple_subquery().)
561 : */
562 1066 : if (parse->groupingSets)
563 12 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
564 :
565 : /*
566 : * Apply pullup variable replacement throughout the query tree.
567 : */
568 1066 : parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
569 : }
570 :
571 477088 : return parse;
572 : }
573 :
574 : /*
575 : * replace_empty_jointree
576 : * If the Query's jointree is empty, replace it with a dummy RTE_RESULT
577 : * relation.
578 : *
579 : * By doing this, we can avoid a bunch of corner cases that formerly existed
580 : * for SELECTs with omitted FROM clauses. An example is that a subquery
581 : * with empty jointree previously could not be pulled up, because that would
582 : * have resulted in an empty relid set, making the subquery not uniquely
583 : * identifiable for join or PlaceHolderVar processing.
584 : *
585 : * Unlike most other functions in this file, this function doesn't recurse;
586 : * we rely on other processing to invoke it on sub-queries at suitable times.
587 : */
588 : void
589 571876 : replace_empty_jointree(Query *parse)
590 : {
591 : RangeTblEntry *rte;
592 : Index rti;
593 : RangeTblRef *rtr;
594 :
595 : /* Nothing to do if jointree is already nonempty */
596 571876 : if (parse->jointree->fromlist != NIL)
597 372902 : return;
598 :
599 : /* We mustn't change it in the top level of a setop tree, either */
600 205872 : if (parse->setOperations)
601 6898 : return;
602 :
603 : /* Create suitable RTE */
604 198974 : rte = makeNode(RangeTblEntry);
605 198974 : rte->rtekind = RTE_RESULT;
606 198974 : rte->eref = makeAlias("*RESULT*", NIL);
607 :
608 : /* Add it to rangetable */
609 198974 : parse->rtable = lappend(parse->rtable, rte);
610 198974 : rti = list_length(parse->rtable);
611 :
612 : /* And jam a reference into the jointree */
613 198974 : rtr = makeNode(RangeTblRef);
614 198974 : rtr->rtindex = rti;
615 198974 : parse->jointree->fromlist = list_make1(rtr);
616 : }
617 :
618 : /*
619 : * pull_up_sublinks
620 : * Attempt to pull up ANY and EXISTS SubLinks to be treated as
621 : * semijoins or anti-semijoins.
622 : *
623 : * A clause "foo op ANY (sub-SELECT)" can be processed by pulling the
624 : * sub-SELECT up to become a rangetable entry and treating the implied
625 : * comparisons as quals of a semijoin. However, this optimization *only*
626 : * works at the top level of WHERE or a JOIN/ON clause, because we cannot
627 : * distinguish whether the ANY ought to return FALSE or NULL in cases
628 : * involving NULL inputs. Also, in an outer join's ON clause we can only
629 : * do this if the sublink is degenerate (ie, references only the nullable
630 : * side of the join). In that case it is legal to push the semijoin
631 : * down into the nullable side of the join. If the sublink references any
632 : * nonnullable-side variables then it would have to be evaluated as part
633 : * of the outer join, which makes things way too complicated.
634 : *
635 : * Under similar conditions, EXISTS and NOT EXISTS clauses can be handled
636 : * by pulling up the sub-SELECT and creating a semijoin or anti-semijoin.
637 : *
638 : * This routine searches for such clauses and does the necessary parsetree
639 : * transformations if any are found.
640 : *
641 : * This routine has to run before preprocess_expression(), so the quals
642 : * clauses are not yet reduced to implicit-AND format, and are not guaranteed
643 : * to be AND/OR-flat either. That means we need to recursively search through
644 : * explicit AND clauses. We stop as soon as we hit a non-AND item.
645 : */
646 : void
647 38726 : pull_up_sublinks(PlannerInfo *root)
648 : {
649 : Node *jtnode;
650 : Relids relids;
651 :
652 : /* Begin recursion through the jointree */
653 38726 : jtnode = pull_up_sublinks_jointree_recurse(root,
654 38726 : (Node *) root->parse->jointree,
655 : &relids);
656 :
657 : /*
658 : * root->parse->jointree must always be a FromExpr, so insert a dummy one
659 : * if we got a bare RangeTblRef or JoinExpr out of the recursion.
660 : */
661 38726 : if (IsA(jtnode, FromExpr))
662 30944 : root->parse->jointree = (FromExpr *) jtnode;
663 : else
664 7782 : root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
665 38726 : }
666 :
667 : /*
668 : * Recurse through jointree nodes for pull_up_sublinks()
669 : *
670 : * In addition to returning the possibly-modified jointree node, we return
671 : * a relids set of the contained rels into *relids.
672 : */
673 : static Node *
674 129736 : pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
675 : Relids *relids)
676 : {
677 : /* Since this function recurses, it could be driven to stack overflow. */
678 129736 : check_stack_depth();
679 :
680 129736 : if (jtnode == NULL)
681 : {
682 0 : *relids = NULL;
683 : }
684 129736 : else if (IsA(jtnode, RangeTblRef))
685 : {
686 70514 : int varno = ((RangeTblRef *) jtnode)->rtindex;
687 :
688 70514 : *relids = bms_make_singleton(varno);
689 : /* jtnode is returned unmodified */
690 : }
691 59222 : else if (IsA(jtnode, FromExpr))
692 : {
693 38954 : FromExpr *f = (FromExpr *) jtnode;
694 38954 : List *newfromlist = NIL;
695 38954 : Relids frelids = NULL;
696 : FromExpr *newf;
697 : Node *jtlink;
698 : ListCell *l;
699 :
700 : /* First, recurse to process children and collect their relids */
701 81424 : foreach(l, f->fromlist)
702 : {
703 : Node *newchild;
704 : Relids childrelids;
705 :
706 42470 : newchild = pull_up_sublinks_jointree_recurse(root,
707 42470 : lfirst(l),
708 : &childrelids);
709 42470 : newfromlist = lappend(newfromlist, newchild);
710 42470 : frelids = bms_join(frelids, childrelids);
711 : }
712 : /* Build the replacement FromExpr; no quals yet */
713 38954 : newf = makeFromExpr(newfromlist, NULL);
714 : /* Set up a link representing the rebuilt jointree */
715 38954 : jtlink = (Node *) newf;
716 : /* Now process qual --- all children are available for use */
717 38954 : newf->quals = pull_up_sublinks_qual_recurse(root, f->quals,
718 : &jtlink, frelids,
719 : NULL, NULL);
720 :
721 : /*
722 : * Note that the result will be either newf, or a stack of JoinExprs
723 : * with newf at the base. We rely on subsequent optimization steps to
724 : * flatten this and rearrange the joins as needed.
725 : *
726 : * Although we could include the pulled-up subqueries in the returned
727 : * relids, there's no need since upper quals couldn't refer to their
728 : * outputs anyway.
729 : */
730 38954 : *relids = frelids;
731 38954 : jtnode = jtlink;
732 : }
733 20268 : else if (IsA(jtnode, JoinExpr))
734 : {
735 : JoinExpr *j;
736 : Relids leftrelids;
737 : Relids rightrelids;
738 : Node *jtlink;
739 :
740 : /*
741 : * Make a modifiable copy of join node, but don't bother copying its
742 : * subnodes (yet).
743 : */
744 20268 : j = (JoinExpr *) palloc(sizeof(JoinExpr));
745 20268 : memcpy(j, jtnode, sizeof(JoinExpr));
746 20268 : jtlink = (Node *) j;
747 :
748 : /* Recurse to process children and collect their relids */
749 20268 : j->larg = pull_up_sublinks_jointree_recurse(root, j->larg,
750 : &leftrelids);
751 20268 : j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg,
752 : &rightrelids);
753 :
754 : /*
755 : * Now process qual, showing appropriate child relids as available,
756 : * and attach any pulled-up jointree items at the right place. In the
757 : * inner-join case we put new JoinExprs above the existing one (much
758 : * as for a FromExpr-style join). In outer-join cases the new
759 : * JoinExprs must go into the nullable side of the outer join. The
760 : * point of the available_rels machinations is to ensure that we only
761 : * pull up quals for which that's okay.
762 : *
763 : * We don't expect to see any pre-existing JOIN_SEMI, JOIN_ANTI,
764 : * JOIN_RIGHT_SEMI, or JOIN_RIGHT_ANTI jointypes here.
765 : */
766 20268 : switch (j->jointype)
767 : {
768 9138 : case JOIN_INNER:
769 9138 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
770 : &jtlink,
771 : bms_union(leftrelids,
772 : rightrelids),
773 : NULL, NULL);
774 9138 : break;
775 11022 : case JOIN_LEFT:
776 11022 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
777 : &j->rarg,
778 : rightrelids,
779 : NULL, NULL);
780 11022 : break;
781 12 : case JOIN_FULL:
782 : /* can't do anything with full-join quals */
783 12 : break;
784 96 : case JOIN_RIGHT:
785 96 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
786 : &j->larg,
787 : leftrelids,
788 : NULL, NULL);
789 96 : break;
790 0 : default:
791 0 : elog(ERROR, "unrecognized join type: %d",
792 : (int) j->jointype);
793 : break;
794 : }
795 :
796 : /*
797 : * Although we could include the pulled-up subqueries in the returned
798 : * relids, there's no need since upper quals couldn't refer to their
799 : * outputs anyway. But we *do* need to include the join's own rtindex
800 : * because we haven't yet collapsed join alias variables, so upper
801 : * levels would mistakenly think they couldn't use references to this
802 : * join.
803 : */
804 20268 : *relids = bms_join(leftrelids, rightrelids);
805 20268 : if (j->rtindex)
806 20268 : *relids = bms_add_member(*relids, j->rtindex);
807 20268 : jtnode = jtlink;
808 : }
809 : else
810 0 : elog(ERROR, "unrecognized node type: %d",
811 : (int) nodeTag(jtnode));
812 129736 : return jtnode;
813 : }
814 :
815 : /*
816 : * Recurse through top-level qual nodes for pull_up_sublinks()
817 : *
818 : * jtlink1 points to the link in the jointree where any new JoinExprs should
819 : * be inserted if they reference available_rels1 (i.e., available_rels1
820 : * denotes the relations present underneath jtlink1). Optionally, jtlink2 can
821 : * point to a second link where new JoinExprs should be inserted if they
822 : * reference available_rels2 (pass NULL for both those arguments if not used).
823 : * Note that SubLinks referencing both sets of variables cannot be optimized.
824 : * If we find multiple pull-up-able SubLinks, they'll get stacked onto jtlink1
825 : * and/or jtlink2 in the order we encounter them. We rely on subsequent
826 : * optimization to rearrange the stack if appropriate.
827 : *
828 : * Returns the replacement qual node, or NULL if the qual should be removed.
829 : */
830 : static Node *
831 121776 : pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
832 : Node **jtlink1, Relids available_rels1,
833 : Node **jtlink2, Relids available_rels2)
834 : {
835 121776 : if (node == NULL)
836 7474 : return NULL;
837 114302 : if (IsA(node, SubLink))
838 : {
839 5644 : SubLink *sublink = (SubLink *) node;
840 : JoinExpr *j;
841 : Relids child_rels;
842 :
843 : /* Is it a convertible ANY or EXISTS clause? */
844 5644 : if (sublink->subLinkType == ANY_SUBLINK)
845 : {
846 : ScalarArrayOpExpr *saop;
847 :
848 4666 : if ((saop = convert_VALUES_to_ANY(root,
849 : sublink->testexpr,
850 4666 : (Query *) sublink->subselect)) != NULL)
851 :
852 : /*
853 : * The VALUES sequence was simplified. Nothing more to do
854 : * here.
855 : */
856 84 : return (Node *) saop;
857 :
858 4582 : if ((j = convert_ANY_sublink_to_join(root, sublink,
859 : available_rels1)) != NULL)
860 : {
861 : /* Yes; insert the new join node into the join tree */
862 4476 : j->larg = *jtlink1;
863 4476 : *jtlink1 = (Node *) j;
864 : /* Recursively process pulled-up jointree nodes */
865 4476 : j->rarg = pull_up_sublinks_jointree_recurse(root,
866 : j->rarg,
867 : &child_rels);
868 :
869 : /*
870 : * Now recursively process the pulled-up quals. Any inserted
871 : * joins can get stacked onto either j->larg or j->rarg,
872 : * depending on which rels they reference.
873 : */
874 4476 : j->quals = pull_up_sublinks_qual_recurse(root,
875 : j->quals,
876 : &j->larg,
877 : available_rels1,
878 : &j->rarg,
879 : child_rels);
880 : /* Return NULL representing constant TRUE */
881 4476 : return NULL;
882 : }
883 112 : if (available_rels2 != NULL &&
884 6 : (j = convert_ANY_sublink_to_join(root, sublink,
885 : available_rels2)) != NULL)
886 : {
887 : /* Yes; insert the new join node into the join tree */
888 0 : j->larg = *jtlink2;
889 0 : *jtlink2 = (Node *) j;
890 : /* Recursively process pulled-up jointree nodes */
891 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
892 : j->rarg,
893 : &child_rels);
894 :
895 : /*
896 : * Now recursively process the pulled-up quals. Any inserted
897 : * joins can get stacked onto either j->larg or j->rarg,
898 : * depending on which rels they reference.
899 : */
900 0 : j->quals = pull_up_sublinks_qual_recurse(root,
901 : j->quals,
902 : &j->larg,
903 : available_rels2,
904 : &j->rarg,
905 : child_rels);
906 : /* Return NULL representing constant TRUE */
907 0 : return NULL;
908 : }
909 : }
910 978 : else if (sublink->subLinkType == EXISTS_SUBLINK)
911 : {
912 918 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, false,
913 : available_rels1)) != NULL)
914 : {
915 : /* Yes; insert the new join node into the join tree */
916 754 : j->larg = *jtlink1;
917 754 : *jtlink1 = (Node *) j;
918 : /* Recursively process pulled-up jointree nodes */
919 754 : j->rarg = pull_up_sublinks_jointree_recurse(root,
920 : j->rarg,
921 : &child_rels);
922 :
923 : /*
924 : * Now recursively process the pulled-up quals. Any inserted
925 : * joins can get stacked onto either j->larg or j->rarg,
926 : * depending on which rels they reference.
927 : */
928 754 : j->quals = pull_up_sublinks_qual_recurse(root,
929 : j->quals,
930 : &j->larg,
931 : available_rels1,
932 : &j->rarg,
933 : child_rels);
934 : /* Return NULL representing constant TRUE */
935 754 : return NULL;
936 : }
937 196 : if (available_rels2 != NULL &&
938 32 : (j = convert_EXISTS_sublink_to_join(root, sublink, false,
939 : available_rels2)) != NULL)
940 : {
941 : /* Yes; insert the new join node into the join tree */
942 32 : j->larg = *jtlink2;
943 32 : *jtlink2 = (Node *) j;
944 : /* Recursively process pulled-up jointree nodes */
945 32 : j->rarg = pull_up_sublinks_jointree_recurse(root,
946 : j->rarg,
947 : &child_rels);
948 :
949 : /*
950 : * Now recursively process the pulled-up quals. Any inserted
951 : * joins can get stacked onto either j->larg or j->rarg,
952 : * depending on which rels they reference.
953 : */
954 32 : j->quals = pull_up_sublinks_qual_recurse(root,
955 : j->quals,
956 : &j->larg,
957 : available_rels2,
958 : &j->rarg,
959 : child_rels);
960 : /* Return NULL representing constant TRUE */
961 32 : return NULL;
962 : }
963 : }
964 : /* Else return it unmodified */
965 298 : return node;
966 : }
967 108658 : if (is_notclause(node))
968 : {
969 : /* If the immediate argument of NOT is EXISTS, try to convert */
970 7442 : SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
971 : JoinExpr *j;
972 : Relids child_rels;
973 :
974 7442 : if (sublink && IsA(sublink, SubLink))
975 : {
976 2852 : if (sublink->subLinkType == EXISTS_SUBLINK)
977 : {
978 2756 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, true,
979 : available_rels1)) != NULL)
980 : {
981 : /* Yes; insert the new join node into the join tree */
982 2742 : j->larg = *jtlink1;
983 2742 : *jtlink1 = (Node *) j;
984 : /* Recursively process pulled-up jointree nodes */
985 2742 : j->rarg = pull_up_sublinks_jointree_recurse(root,
986 : j->rarg,
987 : &child_rels);
988 :
989 : /*
990 : * Now recursively process the pulled-up quals. Because
991 : * we are underneath a NOT, we can't pull up sublinks that
992 : * reference the left-hand stuff, but it's still okay to
993 : * pull up sublinks referencing j->rarg.
994 : */
995 2742 : j->quals = pull_up_sublinks_qual_recurse(root,
996 : j->quals,
997 : &j->rarg,
998 : child_rels,
999 : NULL, NULL);
1000 : /* Return NULL representing constant TRUE */
1001 2742 : return NULL;
1002 : }
1003 14 : if (available_rels2 != NULL &&
1004 0 : (j = convert_EXISTS_sublink_to_join(root, sublink, true,
1005 : available_rels2)) != NULL)
1006 : {
1007 : /* Yes; insert the new join node into the join tree */
1008 0 : j->larg = *jtlink2;
1009 0 : *jtlink2 = (Node *) j;
1010 : /* Recursively process pulled-up jointree nodes */
1011 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1012 : j->rarg,
1013 : &child_rels);
1014 :
1015 : /*
1016 : * Now recursively process the pulled-up quals. Because
1017 : * we are underneath a NOT, we can't pull up sublinks that
1018 : * reference the left-hand stuff, but it's still okay to
1019 : * pull up sublinks referencing j->rarg.
1020 : */
1021 0 : j->quals = pull_up_sublinks_qual_recurse(root,
1022 : j->quals,
1023 : &j->rarg,
1024 : child_rels,
1025 : NULL, NULL);
1026 : /* Return NULL representing constant TRUE */
1027 0 : return NULL;
1028 : }
1029 : }
1030 : }
1031 : /* Else return it unmodified */
1032 4700 : return node;
1033 : }
1034 101216 : if (is_andclause(node))
1035 : {
1036 : /* Recurse into AND clause */
1037 18976 : List *newclauses = NIL;
1038 : ListCell *l;
1039 :
1040 73538 : foreach(l, ((BoolExpr *) node)->args)
1041 : {
1042 54562 : Node *oldclause = (Node *) lfirst(l);
1043 : Node *newclause;
1044 :
1045 54562 : newclause = pull_up_sublinks_qual_recurse(root,
1046 : oldclause,
1047 : jtlink1,
1048 : available_rels1,
1049 : jtlink2,
1050 : available_rels2);
1051 54562 : if (newclause)
1052 48922 : newclauses = lappend(newclauses, newclause);
1053 : }
1054 : /* We might have got back fewer clauses than we started with */
1055 18976 : if (newclauses == NIL)
1056 124 : return NULL;
1057 18852 : else if (list_length(newclauses) == 1)
1058 1146 : return (Node *) linitial(newclauses);
1059 : else
1060 17706 : return (Node *) make_andclause(newclauses);
1061 : }
1062 : /* Stop if not an AND */
1063 82240 : return node;
1064 : }
1065 :
1066 : /*
1067 : * preprocess_function_rtes
1068 : * Constant-simplify any FUNCTION RTEs in the FROM clause, and then
1069 : * attempt to "inline" any that can be converted to simple subqueries.
1070 : *
1071 : * If an RTE_FUNCTION rtable entry invokes a set-returning SQL function that
1072 : * contains just a simple SELECT, we can convert the rtable entry to an
1073 : * RTE_SUBQUERY entry exposing the SELECT directly. Other sorts of functions
1074 : * are also inline-able if they have a support function that can generate
1075 : * the replacement sub-Query. This is especially useful if the subquery can
1076 : * then be "pulled up" for further optimization, but we do it even if not,
1077 : * to reduce executor overhead.
1078 : *
1079 : * This has to be done before we have started to do any optimization of
1080 : * subqueries, else any such steps wouldn't get applied to subqueries
1081 : * obtained via inlining. However, we do it after pull_up_sublinks
1082 : * so that we can inline any functions used in SubLink subselects.
1083 : *
1084 : * The reason for applying const-simplification at this stage is that
1085 : * (a) we'd need to do it anyway to inline a SRF, and (b) by doing it now,
1086 : * we can be sure that pull_up_constant_function() will see constants
1087 : * if there are constants to be seen. This approach also guarantees
1088 : * that every FUNCTION RTE has been const-simplified, allowing planner.c's
1089 : * preprocess_expression() to skip doing it again.
1090 : *
1091 : * Like most of the planner, this feels free to scribble on its input data
1092 : * structure.
1093 : */
1094 : void
1095 568304 : preprocess_function_rtes(PlannerInfo *root)
1096 : {
1097 : ListCell *rt;
1098 :
1099 1478060 : foreach(rt, root->parse->rtable)
1100 : {
1101 909762 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
1102 :
1103 909762 : if (rte->rtekind == RTE_FUNCTION)
1104 : {
1105 : Query *funcquery;
1106 :
1107 : /* Apply const-simplification */
1108 53132 : rte->functions = (List *)
1109 53132 : eval_const_expressions(root, (Node *) rte->functions);
1110 :
1111 : /* Check safety of expansion, and expand if possible */
1112 53132 : funcquery = inline_function_in_from(root, rte);
1113 53126 : if (funcquery)
1114 : {
1115 : /* Successful expansion, convert the RTE to a subquery */
1116 246 : rte->rtekind = RTE_SUBQUERY;
1117 246 : rte->subquery = funcquery;
1118 246 : rte->security_barrier = false;
1119 :
1120 : /*
1121 : * Clear fields that should not be set in a subquery RTE.
1122 : * However, we leave rte->functions filled in for the moment,
1123 : * in case makeWholeRowVar needs to consult it. We'll clear
1124 : * it in setrefs.c (see add_rte_to_flat_rtable) so that this
1125 : * abuse of the data structure doesn't escape the planner.
1126 : */
1127 246 : rte->funcordinality = false;
1128 : }
1129 : }
1130 : }
1131 568298 : }
1132 :
1133 : /*
1134 : * pull_up_subqueries
1135 : * Look for subqueries in the rangetable that can be pulled up into
1136 : * the parent query. If the subquery has no special features like
1137 : * grouping/aggregation then we can merge it into the parent's jointree.
1138 : * Also, subqueries that are simple UNION ALL structures can be
1139 : * converted into "append relations".
1140 : */
1141 : void
1142 568298 : pull_up_subqueries(PlannerInfo *root)
1143 : {
1144 : /* Top level of jointree must always be a FromExpr */
1145 : Assert(IsA(root->parse->jointree, FromExpr));
1146 : /* Recursion starts with no containing join nor appendrel */
1147 1136590 : root->parse->jointree = (FromExpr *)
1148 568298 : pull_up_subqueries_recurse(root, (Node *) root->parse->jointree,
1149 : NULL, NULL);
1150 : /* We should still have a FromExpr */
1151 : Assert(IsA(root->parse->jointree, FromExpr));
1152 568292 : }
1153 :
1154 : /*
1155 : * pull_up_subqueries_recurse
1156 : * Recursive guts of pull_up_subqueries.
1157 : *
1158 : * This recursively processes the jointree and returns a modified jointree.
1159 : *
1160 : * If this jointree node is within either side of an outer join, then
1161 : * lowest_outer_join references the lowest such JoinExpr node; otherwise
1162 : * it is NULL. We use this to constrain the effects of LATERAL subqueries.
1163 : *
1164 : * If we are looking at a member subquery of an append relation,
1165 : * containing_appendrel describes that relation; else it is NULL.
1166 : * This forces use of the PlaceHolderVar mechanism for all non-Var targetlist
1167 : * items, and puts some additional restrictions on what can be pulled up.
1168 : *
1169 : * A tricky aspect of this code is that if we pull up a subquery we have
1170 : * to replace Vars that reference the subquery's outputs throughout the
1171 : * parent query, including quals attached to jointree nodes above the one
1172 : * we are currently processing! We handle this by being careful to maintain
1173 : * validity of the jointree structure while recursing, in the following sense:
1174 : * whenever we recurse, all qual expressions in the tree must be reachable
1175 : * from the top level, in case the recursive call needs to modify them.
1176 : *
1177 : * Notice also that we can't turn pullup_replace_vars loose on the whole
1178 : * jointree, because it'd return a mutated copy of the tree; we have to
1179 : * invoke it just on the quals, instead. This behavior is what makes it
1180 : * reasonable to pass lowest_outer_join as a pointer rather than some
1181 : * more-indirect way of identifying the lowest OJ. Likewise, we don't
1182 : * replace append_rel_list members but only their substructure, so the
1183 : * containing_appendrel reference is safe to use.
1184 : */
1185 : static Node *
1186 1410686 : pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
1187 : JoinExpr *lowest_outer_join,
1188 : AppendRelInfo *containing_appendrel)
1189 : {
1190 : /* Since this function recurses, it could be driven to stack overflow. */
1191 1410686 : check_stack_depth();
1192 : /* Also, since it's a bit expensive, let's check for query cancel. */
1193 1410686 : CHECK_FOR_INTERRUPTS();
1194 :
1195 : Assert(jtnode != NULL);
1196 1410686 : if (IsA(jtnode, RangeTblRef))
1197 : {
1198 730320 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1199 730320 : RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
1200 :
1201 : /*
1202 : * Is this a subquery RTE, and if so, is the subquery simple enough to
1203 : * pull up?
1204 : *
1205 : * If we are looking at an append-relation member, we can't pull it up
1206 : * unless is_safe_append_member says so.
1207 : */
1208 790578 : if (rte->rtekind == RTE_SUBQUERY &&
1209 104132 : is_simple_subquery(root, rte->subquery, rte, lowest_outer_join) &&
1210 12384 : (containing_appendrel == NULL ||
1211 12384 : is_safe_append_member(rte->subquery)))
1212 37936 : return pull_up_simple_subquery(root, jtnode, rte,
1213 : lowest_outer_join,
1214 : containing_appendrel);
1215 :
1216 : /*
1217 : * Alternatively, is it a simple UNION ALL subquery? If so, flatten
1218 : * into an "append relation".
1219 : *
1220 : * It's safe to do this regardless of whether this query is itself an
1221 : * appendrel member. (If you're thinking we should try to flatten the
1222 : * two levels of appendrel together, you're right; but we handle that
1223 : * in set_append_rel_pathlist, not here.)
1224 : */
1225 714706 : if (rte->rtekind == RTE_SUBQUERY &&
1226 22322 : is_simple_union_all(rte->subquery))
1227 4804 : return pull_up_simple_union_all(root, jtnode, rte);
1228 :
1229 : /*
1230 : * Or perhaps it's a simple VALUES RTE?
1231 : *
1232 : * We don't allow VALUES pullup below an outer join nor into an
1233 : * appendrel (such cases are impossible anyway at the moment).
1234 : */
1235 687580 : if (rte->rtekind == RTE_VALUES &&
1236 12812 : lowest_outer_join == NULL &&
1237 12812 : containing_appendrel == NULL &&
1238 12812 : is_simple_values(root, rte))
1239 4514 : return pull_up_simple_values(root, jtnode, rte);
1240 :
1241 : /*
1242 : * Or perhaps it's a FUNCTION RTE that we could inline?
1243 : */
1244 683066 : if (rte->rtekind == RTE_FUNCTION)
1245 52880 : return pull_up_constant_function(root, jtnode, rte,
1246 : containing_appendrel);
1247 :
1248 : /* Otherwise, do nothing at this node. */
1249 : }
1250 680366 : else if (IsA(jtnode, FromExpr))
1251 : {
1252 578060 : FromExpr *f = (FromExpr *) jtnode;
1253 : ListCell *l;
1254 :
1255 : Assert(containing_appendrel == NULL);
1256 : /* Recursively transform all the child nodes */
1257 1199668 : foreach(l, f->fromlist)
1258 : {
1259 621614 : lfirst(l) = pull_up_subqueries_recurse(root, lfirst(l),
1260 : lowest_outer_join,
1261 : NULL);
1262 : }
1263 : }
1264 102306 : else if (IsA(jtnode, JoinExpr))
1265 : {
1266 102306 : JoinExpr *j = (JoinExpr *) jtnode;
1267 :
1268 : Assert(containing_appendrel == NULL);
1269 : /* Recurse, being careful to tell myself when inside outer join */
1270 102306 : switch (j->jointype)
1271 : {
1272 45606 : case JOIN_INNER:
1273 45606 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1274 : lowest_outer_join,
1275 : NULL);
1276 45606 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1277 : lowest_outer_join,
1278 : NULL);
1279 45606 : break;
1280 54384 : case JOIN_LEFT:
1281 : case JOIN_SEMI:
1282 : case JOIN_ANTI:
1283 54384 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1284 : j,
1285 : NULL);
1286 54384 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1287 : j,
1288 : NULL);
1289 54384 : break;
1290 1096 : case JOIN_FULL:
1291 1096 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1292 : j,
1293 : NULL);
1294 1096 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1295 : j,
1296 : NULL);
1297 1096 : break;
1298 1220 : case JOIN_RIGHT:
1299 1220 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1300 : j,
1301 : NULL);
1302 1220 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1303 : j,
1304 : NULL);
1305 1220 : break;
1306 0 : default:
1307 0 : elog(ERROR, "unrecognized join type: %d",
1308 : (int) j->jointype);
1309 : break;
1310 : }
1311 : }
1312 : else
1313 0 : elog(ERROR, "unrecognized node type: %d",
1314 : (int) nodeTag(jtnode));
1315 1310546 : return jtnode;
1316 : }
1317 :
1318 : /*
1319 : * pull_up_simple_subquery
1320 : * Attempt to pull up a single simple subquery.
1321 : *
1322 : * jtnode is a RangeTblRef that has been tentatively identified as a simple
1323 : * subquery by pull_up_subqueries. We return the replacement jointree node,
1324 : * or jtnode itself if we determine that the subquery can't be pulled up
1325 : * after all.
1326 : *
1327 : * rte is the RangeTblEntry referenced by jtnode. Remaining parameters are
1328 : * as for pull_up_subqueries_recurse.
1329 : */
1330 : static Node *
1331 37936 : pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
1332 : JoinExpr *lowest_outer_join,
1333 : AppendRelInfo *containing_appendrel)
1334 : {
1335 37936 : Query *parse = root->parse;
1336 37936 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1337 : Query *subquery;
1338 : PlannerInfo *subroot;
1339 : int rtoffset;
1340 : pullup_replace_vars_context rvcontext;
1341 : ListCell *lc;
1342 :
1343 : /*
1344 : * Make a modifiable copy of the subquery to hack on, so that the RTE will
1345 : * be left unchanged in case we decide below that we can't pull it up
1346 : * after all.
1347 : */
1348 37936 : subquery = copyObject(rte->subquery);
1349 :
1350 : /*
1351 : * Create a PlannerInfo data structure for this subquery.
1352 : *
1353 : * NOTE: the next few steps should match the first processing in
1354 : * subquery_planner(). Can we refactor to avoid code duplication, or
1355 : * would that just make things uglier?
1356 : */
1357 37936 : subroot = makeNode(PlannerInfo);
1358 37936 : subroot->parse = subquery;
1359 37936 : subroot->glob = root->glob;
1360 37936 : subroot->query_level = root->query_level;
1361 37936 : subroot->plan_name = root->plan_name;
1362 37936 : subroot->parent_root = root->parent_root;
1363 37936 : subroot->plan_params = NIL;
1364 37936 : subroot->outer_params = NULL;
1365 37936 : subroot->planner_cxt = CurrentMemoryContext;
1366 37936 : subroot->init_plans = NIL;
1367 37936 : subroot->cte_plan_ids = NIL;
1368 37936 : subroot->multiexpr_params = NIL;
1369 37936 : subroot->join_domains = NIL;
1370 37936 : subroot->eq_classes = NIL;
1371 37936 : subroot->ec_merging_done = false;
1372 37936 : subroot->last_rinfo_serial = 0;
1373 37936 : subroot->all_result_relids = NULL;
1374 37936 : subroot->leaf_result_relids = NULL;
1375 37936 : subroot->append_rel_list = NIL;
1376 37936 : subroot->row_identity_vars = NIL;
1377 37936 : subroot->rowMarks = NIL;
1378 37936 : memset(subroot->upper_rels, 0, sizeof(subroot->upper_rels));
1379 37936 : memset(subroot->upper_targets, 0, sizeof(subroot->upper_targets));
1380 37936 : subroot->processed_groupClause = NIL;
1381 37936 : subroot->processed_distinctClause = NIL;
1382 37936 : subroot->processed_tlist = NIL;
1383 37936 : subroot->update_colnos = NIL;
1384 37936 : subroot->grouping_map = NULL;
1385 37936 : subroot->minmax_aggs = NIL;
1386 37936 : subroot->qual_security_level = 0;
1387 37936 : subroot->placeholdersFrozen = false;
1388 37936 : subroot->hasRecursion = false;
1389 37936 : subroot->assumeReplanning = false;
1390 37936 : subroot->wt_param_id = -1;
1391 37936 : subroot->non_recursive_path = NULL;
1392 : /* We don't currently need a top JoinDomain for the subroot */
1393 :
1394 : /* No CTEs to worry about */
1395 : Assert(subquery->cteList == NIL);
1396 :
1397 : /*
1398 : * Scan the rangetable for relation RTEs and retrieve the necessary
1399 : * catalog information for each relation. Using this information, clear
1400 : * the inh flag for any relation that has no children, collect not-null
1401 : * attribute numbers for any relation that has column not-null
1402 : * constraints, and expand virtual generated columns for any relation that
1403 : * contains them.
1404 : */
1405 37936 : subquery = subroot->parse = preprocess_relation_rtes(subroot);
1406 :
1407 : /*
1408 : * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
1409 : * that we don't need so many special cases to deal with that situation.
1410 : */
1411 37936 : replace_empty_jointree(subquery);
1412 :
1413 : /*
1414 : * Pull up any SubLinks within the subquery's quals, so that we don't
1415 : * leave unoptimized SubLinks behind.
1416 : */
1417 37936 : if (subquery->hasSubLinks)
1418 2384 : pull_up_sublinks(subroot);
1419 :
1420 : /*
1421 : * Similarly, preprocess its function RTEs to inline any set-returning
1422 : * functions in its rangetable.
1423 : */
1424 37936 : preprocess_function_rtes(subroot);
1425 :
1426 : /*
1427 : * Recursively pull up the subquery's subqueries, so that
1428 : * pull_up_subqueries' processing is complete for its jointree and
1429 : * rangetable.
1430 : *
1431 : * Note: it's okay that the subquery's recursion starts with NULL for
1432 : * containing-join info, even if we are within an outer join in the upper
1433 : * query; the lower query starts with a clean slate for outer-join
1434 : * semantics. Likewise, we needn't pass down appendrel state.
1435 : */
1436 37936 : pull_up_subqueries(subroot);
1437 :
1438 : /*
1439 : * Now we must recheck whether the subquery is still simple enough to pull
1440 : * up. If not, abandon processing it.
1441 : *
1442 : * We don't really need to recheck all the conditions involved, but it's
1443 : * easier just to keep this "if" looking the same as the one in
1444 : * pull_up_subqueries_recurse.
1445 : */
1446 37936 : if (is_simple_subquery(root, subquery, rte, lowest_outer_join) &&
1447 6446 : (containing_appendrel == NULL || is_safe_append_member(subquery)))
1448 : {
1449 : /* good to go */
1450 : }
1451 : else
1452 : {
1453 : /*
1454 : * Give up, return unmodified RangeTblRef.
1455 : *
1456 : * Note: The work we just did will be redone when the subquery gets
1457 : * planned on its own. Perhaps we could avoid that by storing the
1458 : * modified subquery back into the rangetable, but I'm not gonna risk
1459 : * it now.
1460 : */
1461 228 : return jtnode;
1462 : }
1463 :
1464 : /*
1465 : * We must flatten any join alias Vars in the subquery's targetlist,
1466 : * because pulling up the subquery's subqueries might have changed their
1467 : * expansions into arbitrary expressions, which could affect
1468 : * pullup_replace_vars' decisions about whether PlaceHolderVar wrappers
1469 : * are needed for tlist entries. (Likely it'd be better to do
1470 : * flatten_join_alias_vars on the whole query tree at some earlier stage,
1471 : * maybe even in the rewriter; but for now let's just fix this case here.)
1472 : */
1473 37708 : subquery->targetList = (List *)
1474 37708 : flatten_join_alias_vars(subroot, subroot->parse,
1475 37708 : (Node *) subquery->targetList);
1476 :
1477 : /*
1478 : * Adjust level-0 varnos in subquery so that we can append its rangetable
1479 : * to upper query's. We have to fix the subquery's append_rel_list as
1480 : * well.
1481 : */
1482 37708 : rtoffset = list_length(parse->rtable);
1483 37708 : OffsetVarNodes((Node *) subquery, rtoffset, 0);
1484 37708 : OffsetVarNodes((Node *) subroot->append_rel_list, rtoffset, 0);
1485 :
1486 : /*
1487 : * Upper-level vars in subquery are now one level closer to their parent
1488 : * than before.
1489 : */
1490 37708 : IncrementVarSublevelsUp((Node *) subquery, -1, 1);
1491 37708 : IncrementVarSublevelsUp((Node *) subroot->append_rel_list, -1, 1);
1492 :
1493 : /*
1494 : * The subquery's targetlist items are now in the appropriate form to
1495 : * insert into the top query, except that we may need to wrap them in
1496 : * PlaceHolderVars. Set up required context data for pullup_replace_vars.
1497 : * (Note that we should include the subquery's inner joins in relids,
1498 : * since it may include join alias vars referencing them.)
1499 : */
1500 37708 : rvcontext.root = root;
1501 37708 : rvcontext.targetlist = subquery->targetList;
1502 37708 : rvcontext.target_rte = rte;
1503 37708 : rvcontext.result_relation = 0;
1504 37708 : if (rte->lateral)
1505 : {
1506 1158 : rvcontext.relids = get_relids_in_jointree((Node *) subquery->jointree,
1507 : true, true);
1508 1158 : rvcontext.nullinfo = get_nullingrels(parse);
1509 : }
1510 : else /* won't need these values */
1511 : {
1512 36550 : rvcontext.relids = NULL;
1513 36550 : rvcontext.nullinfo = NULL;
1514 : }
1515 37708 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1516 37708 : rvcontext.varno = varno;
1517 : /* this flag will be set below, if needed */
1518 37708 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
1519 : /* initialize cache array with indexes 0 .. length(tlist) */
1520 37708 : rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
1521 : sizeof(Node *));
1522 :
1523 : /*
1524 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
1525 : * each expression of the subquery's targetlist items. This ensures that
1526 : * expressions retain their separate identity so that they will match
1527 : * grouping set columns when appropriate. (It'd be sufficient to wrap
1528 : * values used in grouping set columns, and do so only in non-aggregated
1529 : * portions of the tlist and havingQual, but that would require a lot of
1530 : * infrastructure that pullup_replace_vars hasn't currently got.)
1531 : */
1532 37708 : if (parse->groupingSets)
1533 332 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
1534 :
1535 : /*
1536 : * Replace all of the top query's references to the subquery's outputs
1537 : * with copies of the adjusted subtlist items, being careful not to
1538 : * replace any of the jointree structure.
1539 : */
1540 37708 : perform_pullup_replace_vars(root, &rvcontext,
1541 : containing_appendrel);
1542 :
1543 : /*
1544 : * If the subquery had a LATERAL marker, propagate that to any of its
1545 : * child RTEs that could possibly now contain lateral cross-references.
1546 : * The children might or might not contain any actual lateral
1547 : * cross-references, but we have to mark the pulled-up child RTEs so that
1548 : * later planner stages will check for such.
1549 : */
1550 37702 : if (rte->lateral)
1551 : {
1552 2712 : foreach(lc, subquery->rtable)
1553 : {
1554 1554 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(lc);
1555 :
1556 1554 : switch (child_rte->rtekind)
1557 : {
1558 696 : case RTE_RELATION:
1559 696 : if (child_rte->tablesample)
1560 36 : child_rte->lateral = true;
1561 696 : break;
1562 280 : case RTE_SUBQUERY:
1563 : case RTE_FUNCTION:
1564 : case RTE_VALUES:
1565 : case RTE_TABLEFUNC:
1566 280 : child_rte->lateral = true;
1567 280 : break;
1568 578 : case RTE_JOIN:
1569 : case RTE_CTE:
1570 : case RTE_NAMEDTUPLESTORE:
1571 : case RTE_RESULT:
1572 : case RTE_GROUP:
1573 : /* these can't contain any lateral references */
1574 578 : break;
1575 : }
1576 : }
1577 : }
1578 :
1579 : /*
1580 : * Now append the adjusted rtable entries and their perminfos to upper
1581 : * query. (We hold off until after fixing the upper rtable entries; no
1582 : * point in running that code on the subquery ones too.)
1583 : */
1584 37702 : CombineRangeTables(&parse->rtable, &parse->rteperminfos,
1585 : subquery->rtable, subquery->rteperminfos);
1586 :
1587 : /*
1588 : * Pull up any FOR UPDATE/SHARE markers, too. (OffsetVarNodes already
1589 : * adjusted the marker rtindexes, so just concat the lists.)
1590 : */
1591 37702 : parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
1592 :
1593 : /*
1594 : * We also have to fix the relid sets of any PlaceHolderVar nodes in the
1595 : * parent query. (This could perhaps be done by pullup_replace_vars(),
1596 : * but it seems cleaner to use two passes.) Note in particular that any
1597 : * PlaceHolderVar nodes just created by pullup_replace_vars() will be
1598 : * adjusted, so having created them with the subquery's varno is correct.
1599 : *
1600 : * Likewise, relids appearing in AppendRelInfo nodes have to be fixed. We
1601 : * already checked that this won't require introducing multiple subrelids
1602 : * into the single-slot AppendRelInfo structs.
1603 : */
1604 37702 : if (root->glob->lastPHId != 0 || root->append_rel_list)
1605 : {
1606 : Relids subrelids;
1607 :
1608 8166 : subrelids = get_relids_in_jointree((Node *) subquery->jointree,
1609 : true, false);
1610 8166 : if (root->glob->lastPHId != 0)
1611 1990 : substitute_phv_relids((Node *) parse, varno, subrelids);
1612 8166 : fix_append_rel_relids(root, varno, subrelids);
1613 : }
1614 :
1615 : /*
1616 : * And now add subquery's AppendRelInfos to our list.
1617 : */
1618 75404 : root->append_rel_list = list_concat(root->append_rel_list,
1619 37702 : subroot->append_rel_list);
1620 :
1621 : /*
1622 : * We don't have to do the equivalent bookkeeping for outer-join info,
1623 : * because that hasn't been set up yet. placeholder_list likewise.
1624 : */
1625 : Assert(root->join_info_list == NIL);
1626 : Assert(subroot->join_info_list == NIL);
1627 : Assert(root->placeholder_list == NIL);
1628 : Assert(subroot->placeholder_list == NIL);
1629 :
1630 : /*
1631 : * We no longer need the RTE's copy of the subquery's query tree. Getting
1632 : * rid of it saves nothing in particular so far as this level of query is
1633 : * concerned; but if this query level is in turn pulled up into a parent,
1634 : * we'd waste cycles copying the now-unused query tree.
1635 : */
1636 37702 : rte->subquery = NULL;
1637 :
1638 : /*
1639 : * Miscellaneous housekeeping.
1640 : *
1641 : * Although replace_rte_variables() faithfully updated parse->hasSubLinks
1642 : * if it copied any SubLinks out of the subquery's targetlist, we still
1643 : * could have SubLinks added to the query in the expressions of FUNCTION
1644 : * and VALUES RTEs copied up from the subquery. So it's necessary to copy
1645 : * subquery->hasSubLinks anyway. Perhaps this can be improved someday.
1646 : */
1647 37702 : parse->hasSubLinks |= subquery->hasSubLinks;
1648 :
1649 : /* If subquery had any RLS conditions, now main query does too */
1650 37702 : parse->hasRowSecurity |= subquery->hasRowSecurity;
1651 :
1652 : /*
1653 : * subquery won't be pulled up if it hasAggs, hasWindowFuncs, or
1654 : * hasTargetSRFs, so no work needed on those flags
1655 : */
1656 :
1657 : /*
1658 : * Return the adjusted subquery jointree to replace the RangeTblRef entry
1659 : * in parent's jointree; or, if the FromExpr is degenerate, just return
1660 : * its single member.
1661 : */
1662 : Assert(IsA(subquery->jointree, FromExpr));
1663 : Assert(subquery->jointree->fromlist != NIL);
1664 69986 : if (subquery->jointree->quals == NULL &&
1665 32284 : list_length(subquery->jointree->fromlist) == 1)
1666 31958 : return (Node *) linitial(subquery->jointree->fromlist);
1667 :
1668 5744 : return (Node *) subquery->jointree;
1669 : }
1670 :
1671 : /*
1672 : * pull_up_simple_union_all
1673 : * Pull up a single simple UNION ALL subquery.
1674 : *
1675 : * jtnode is a RangeTblRef that has been identified as a simple UNION ALL
1676 : * subquery by pull_up_subqueries. We pull up the leaf subqueries and
1677 : * build an "append relation" for the union set. The result value is just
1678 : * jtnode, since we don't actually need to change the query jointree.
1679 : */
1680 : static Node *
1681 4804 : pull_up_simple_union_all(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1682 : {
1683 4804 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1684 4804 : Query *subquery = rte->subquery;
1685 4804 : int rtoffset = list_length(root->parse->rtable);
1686 : List *rtable;
1687 :
1688 : /*
1689 : * Make a modifiable copy of the subquery's rtable, so we can adjust
1690 : * upper-level Vars in it. There are no such Vars in the setOperations
1691 : * tree proper, so fixing the rtable should be sufficient.
1692 : */
1693 4804 : rtable = copyObject(subquery->rtable);
1694 :
1695 : /*
1696 : * Upper-level vars in subquery are now one level closer to their parent
1697 : * than before. We don't have to worry about offsetting varnos, though,
1698 : * because the UNION leaf queries can't cross-reference each other.
1699 : */
1700 4804 : IncrementVarSublevelsUp_rtable(rtable, -1, 1);
1701 :
1702 : /*
1703 : * If the UNION ALL subquery had a LATERAL marker, propagate that to all
1704 : * its children. The individual children might or might not contain any
1705 : * actual lateral cross-references, but we have to mark the pulled-up
1706 : * child RTEs so that later planner stages will check for such.
1707 : */
1708 4804 : if (rte->lateral)
1709 : {
1710 : ListCell *rt;
1711 :
1712 198 : foreach(rt, rtable)
1713 : {
1714 132 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(rt);
1715 :
1716 : Assert(child_rte->rtekind == RTE_SUBQUERY);
1717 132 : child_rte->lateral = true;
1718 : }
1719 : }
1720 :
1721 : /*
1722 : * Append child RTEs (and their perminfos) to parent rtable.
1723 : */
1724 4804 : CombineRangeTables(&root->parse->rtable, &root->parse->rteperminfos,
1725 : rtable, subquery->rteperminfos);
1726 :
1727 : /*
1728 : * Recursively scan the subquery's setOperations tree and add
1729 : * AppendRelInfo nodes for leaf subqueries to the parent's
1730 : * append_rel_list. Also apply pull_up_subqueries to the leaf subqueries.
1731 : */
1732 : Assert(subquery->setOperations);
1733 4804 : pull_up_union_leaf_queries(subquery->setOperations, root, varno, subquery,
1734 : rtoffset);
1735 :
1736 : /*
1737 : * Mark the parent as an append relation.
1738 : */
1739 4804 : rte->inh = true;
1740 :
1741 4804 : return jtnode;
1742 : }
1743 :
1744 : /*
1745 : * pull_up_union_leaf_queries -- recursive guts of pull_up_simple_union_all
1746 : *
1747 : * Build an AppendRelInfo for each leaf query in the setop tree, and then
1748 : * apply pull_up_subqueries to the leaf query.
1749 : *
1750 : * Note that setOpQuery is the Query containing the setOp node, whose tlist
1751 : * contains references to all the setop output columns. When called from
1752 : * pull_up_simple_union_all, this is *not* the same as root->parse, which is
1753 : * the parent Query we are pulling up into.
1754 : *
1755 : * parentRTindex is the appendrel parent's index in root->parse->rtable.
1756 : *
1757 : * The child RTEs have already been copied to the parent. childRToffset
1758 : * tells us where in the parent's range table they were copied. When called
1759 : * from flatten_simple_union_all, childRToffset is 0 since the child RTEs
1760 : * were already in root->parse->rtable and no RT index adjustment is needed.
1761 : */
1762 : static void
1763 26738 : pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
1764 : Query *setOpQuery, int childRToffset)
1765 : {
1766 26738 : if (IsA(setOp, RangeTblRef))
1767 : {
1768 16162 : RangeTblRef *rtr = (RangeTblRef *) setOp;
1769 : int childRTindex;
1770 : AppendRelInfo *appinfo;
1771 :
1772 : /*
1773 : * Calculate the index in the parent's range table
1774 : */
1775 16162 : childRTindex = childRToffset + rtr->rtindex;
1776 :
1777 : /*
1778 : * Build a suitable AppendRelInfo, and attach to parent's list.
1779 : */
1780 16162 : appinfo = makeNode(AppendRelInfo);
1781 16162 : appinfo->parent_relid = parentRTindex;
1782 16162 : appinfo->child_relid = childRTindex;
1783 16162 : appinfo->parent_reltype = InvalidOid;
1784 16162 : appinfo->child_reltype = InvalidOid;
1785 16162 : make_setop_translation_list(setOpQuery, childRTindex, appinfo);
1786 16162 : appinfo->parent_reloid = InvalidOid;
1787 16162 : root->append_rel_list = lappend(root->append_rel_list, appinfo);
1788 :
1789 : /*
1790 : * Recursively apply pull_up_subqueries to the new child RTE. (We
1791 : * must build the AppendRelInfo first, because this will modify it;
1792 : * indeed, that's the only part of the upper query where Vars
1793 : * referencing childRTindex can exist at this point.)
1794 : *
1795 : * Note that we can pass NULL for containing-join info even if we're
1796 : * actually under an outer join, because the child's expressions
1797 : * aren't going to propagate up to the join. Also, we ignore the
1798 : * possibility that pull_up_subqueries_recurse() returns a different
1799 : * jointree node than what we pass it; if it does, the important thing
1800 : * is that it replaced the child relid in the AppendRelInfo node.
1801 : */
1802 16162 : rtr = makeNode(RangeTblRef);
1803 16162 : rtr->rtindex = childRTindex;
1804 16162 : (void) pull_up_subqueries_recurse(root, (Node *) rtr,
1805 : NULL, appinfo);
1806 : }
1807 10576 : else if (IsA(setOp, SetOperationStmt))
1808 : {
1809 10576 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1810 :
1811 : /* Recurse to reach leaf queries */
1812 10576 : pull_up_union_leaf_queries(op->larg, root, parentRTindex, setOpQuery,
1813 : childRToffset);
1814 10576 : pull_up_union_leaf_queries(op->rarg, root, parentRTindex, setOpQuery,
1815 : childRToffset);
1816 : }
1817 : else
1818 : {
1819 0 : elog(ERROR, "unrecognized node type: %d",
1820 : (int) nodeTag(setOp));
1821 : }
1822 26738 : }
1823 :
1824 : /*
1825 : * make_setop_translation_list
1826 : * Build the list of translations from parent Vars to child Vars for
1827 : * a UNION ALL member. (At this point it's just a simple list of
1828 : * referencing Vars, but if we succeed in pulling up the member
1829 : * subquery, the Vars will get replaced by pulled-up expressions.)
1830 : * Also create the rather trivial reverse-translation array.
1831 : */
1832 : static void
1833 16162 : make_setop_translation_list(Query *query, int newvarno,
1834 : AppendRelInfo *appinfo)
1835 : {
1836 16162 : List *vars = NIL;
1837 : AttrNumber *pcolnos;
1838 : ListCell *l;
1839 :
1840 : /* Initialize reverse-translation array with all entries zero */
1841 : /* (entries for resjunk columns will stay that way) */
1842 16162 : appinfo->num_child_cols = list_length(query->targetList);
1843 16162 : appinfo->parent_colnos = pcolnos =
1844 16162 : (AttrNumber *) palloc0(appinfo->num_child_cols * sizeof(AttrNumber));
1845 :
1846 73804 : foreach(l, query->targetList)
1847 : {
1848 57642 : TargetEntry *tle = (TargetEntry *) lfirst(l);
1849 :
1850 57642 : if (tle->resjunk)
1851 0 : continue;
1852 :
1853 57642 : vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
1854 57642 : pcolnos[tle->resno - 1] = tle->resno;
1855 : }
1856 :
1857 16162 : appinfo->translated_vars = vars;
1858 16162 : }
1859 :
1860 : /*
1861 : * is_simple_subquery
1862 : * Check a subquery in the range table to see if it's simple enough
1863 : * to pull up into the parent query.
1864 : *
1865 : * rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
1866 : * (Note subquery is not necessarily equal to rte->subquery; it could be a
1867 : * processed copy of that.)
1868 : * lowest_outer_join is the lowest outer join above the subquery, or NULL.
1869 : */
1870 : static bool
1871 98194 : is_simple_subquery(PlannerInfo *root, Query *subquery, RangeTblEntry *rte,
1872 : JoinExpr *lowest_outer_join)
1873 : {
1874 : /*
1875 : * Let's just make sure it's a valid subselect ...
1876 : */
1877 98194 : if (!IsA(subquery, Query) ||
1878 98194 : subquery->commandType != CMD_SELECT)
1879 0 : elog(ERROR, "subquery is bogus");
1880 :
1881 : /*
1882 : * Can't currently pull up a query with setops (unless it's simple UNION
1883 : * ALL, which is handled by a different code path). Maybe after querytree
1884 : * redesign...
1885 : */
1886 98194 : if (subquery->setOperations)
1887 5646 : return false;
1888 :
1889 : /*
1890 : * Can't pull up a subquery involving grouping, aggregation, SRFs,
1891 : * sorting, limiting, or WITH. (XXX WITH could possibly be allowed later)
1892 : *
1893 : * We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
1894 : * clauses, because pullup would cause the locking to occur semantically
1895 : * higher than it should. Implicit FOR UPDATE/SHARE is okay because in
1896 : * that case the locking was originally declared in the upper query
1897 : * anyway.
1898 : */
1899 92548 : if (subquery->hasAggs ||
1900 90750 : subquery->hasWindowFuncs ||
1901 90364 : subquery->hasTargetSRFs ||
1902 86172 : subquery->groupClause ||
1903 86092 : subquery->groupingSets ||
1904 86092 : subquery->havingQual ||
1905 86092 : subquery->sortClause ||
1906 85216 : subquery->distinctClause ||
1907 84322 : subquery->limitOffset ||
1908 83872 : subquery->limitCount ||
1909 83562 : subquery->hasForUpdate ||
1910 82960 : subquery->cteList)
1911 9756 : return false;
1912 :
1913 : /*
1914 : * Don't pull up if the RTE represents a security-barrier view; we
1915 : * couldn't prevent information leakage once the RTE's Vars are scattered
1916 : * about in the upper query.
1917 : */
1918 82792 : if (rte->security_barrier)
1919 692 : return false;
1920 :
1921 : /*
1922 : * If the subquery is LATERAL, check for pullup restrictions from that.
1923 : */
1924 82100 : if (rte->lateral)
1925 : {
1926 : bool restricted;
1927 : Relids safe_upper_varnos;
1928 :
1929 : /*
1930 : * The subquery's WHERE and JOIN/ON quals mustn't contain any lateral
1931 : * references to rels outside a higher outer join (including the case
1932 : * where the outer join is within the subquery itself). In such a
1933 : * case, pulling up would result in a situation where we need to
1934 : * postpone quals from below an outer join to above it, which is
1935 : * probably completely wrong and in any case is a complication that
1936 : * doesn't seem worth addressing at the moment.
1937 : */
1938 2412 : if (lowest_outer_join != NULL)
1939 : {
1940 1364 : restricted = true;
1941 1364 : safe_upper_varnos = get_relids_in_jointree((Node *) lowest_outer_join,
1942 : true, true);
1943 : }
1944 : else
1945 : {
1946 1048 : restricted = false;
1947 1048 : safe_upper_varnos = NULL; /* doesn't matter */
1948 : }
1949 :
1950 2412 : if (jointree_contains_lateral_outer_refs(root,
1951 2412 : (Node *) subquery->jointree,
1952 : restricted, safe_upper_varnos))
1953 24 : return false;
1954 :
1955 : /*
1956 : * If there's an outer join above the LATERAL subquery, also disallow
1957 : * pullup if the subquery's targetlist has any references to rels
1958 : * outside the outer join, since these might get pulled into quals
1959 : * above the subquery (but in or below the outer join) and then lead
1960 : * to qual-postponement issues similar to the case checked for above.
1961 : * (We wouldn't need to prevent pullup if no such references appear in
1962 : * outer-query quals, but we don't have enough info here to check
1963 : * that. Also, maybe this restriction could be removed if we forced
1964 : * such refs to be wrapped in PlaceHolderVars, even when they're below
1965 : * the nearest outer join? But it's a pretty hokey usage, so not
1966 : * clear this is worth sweating over.)
1967 : *
1968 : * If you change this, see also the comments about lateral references
1969 : * in pullup_replace_vars_callback().
1970 : */
1971 2388 : if (lowest_outer_join != NULL)
1972 : {
1973 1364 : Relids lvarnos = pull_varnos_of_level(root,
1974 1364 : (Node *) subquery->targetList,
1975 : 1);
1976 :
1977 1364 : if (!bms_is_subset(lvarnos, safe_upper_varnos))
1978 12 : return false;
1979 : }
1980 : }
1981 :
1982 : /*
1983 : * Don't pull up a subquery that has any volatile functions in its
1984 : * targetlist. Otherwise we might introduce multiple evaluations of these
1985 : * functions, if they get copied to multiple places in the upper query,
1986 : * leading to surprising results. (Note: the PlaceHolderVar mechanism
1987 : * doesn't quite guarantee single evaluation; else we could pull up anyway
1988 : * and just wrap such items in PlaceHolderVars ...)
1989 : */
1990 82064 : if (contain_volatile_functions((Node *) subquery->targetList))
1991 266 : return false;
1992 :
1993 81798 : return true;
1994 : }
1995 :
1996 : /*
1997 : * pull_up_simple_values
1998 : * Pull up a single simple VALUES RTE.
1999 : *
2000 : * jtnode is a RangeTblRef that has been identified as a simple VALUES RTE
2001 : * by pull_up_subqueries. We always return a RangeTblRef representing a
2002 : * RESULT RTE to replace it (all failure cases should have been detected by
2003 : * is_simple_values()). Actually, what we return is just jtnode, because
2004 : * we replace the VALUES RTE in the rangetable with the RESULT RTE.
2005 : *
2006 : * rte is the RangeTblEntry referenced by jtnode. Because of the limited
2007 : * possible usage of VALUES RTEs, we do not need the remaining parameters
2008 : * of pull_up_subqueries_recurse.
2009 : */
2010 : static Node *
2011 4514 : pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
2012 : {
2013 4514 : Query *parse = root->parse;
2014 4514 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2015 : List *values_list;
2016 : List *tlist;
2017 : AttrNumber attrno;
2018 : pullup_replace_vars_context rvcontext;
2019 : ListCell *lc;
2020 :
2021 : Assert(rte->rtekind == RTE_VALUES);
2022 : Assert(list_length(rte->values_lists) == 1);
2023 :
2024 : /*
2025 : * Need a modifiable copy of the VALUES list to hack on, just in case it's
2026 : * multiply referenced.
2027 : */
2028 4514 : values_list = copyObject(linitial(rte->values_lists));
2029 :
2030 : /*
2031 : * The VALUES RTE can't contain any Vars of level zero, let alone any that
2032 : * are join aliases, so no need to flatten join alias Vars.
2033 : */
2034 : Assert(!contain_vars_of_level((Node *) values_list, 0));
2035 :
2036 : /*
2037 : * Set up required context data for pullup_replace_vars. In particular,
2038 : * we have to make the VALUES list look like a subquery targetlist.
2039 : */
2040 4514 : tlist = NIL;
2041 4514 : attrno = 1;
2042 9764 : foreach(lc, values_list)
2043 : {
2044 5250 : tlist = lappend(tlist,
2045 5250 : makeTargetEntry((Expr *) lfirst(lc),
2046 : attrno,
2047 : NULL,
2048 : false));
2049 5250 : attrno++;
2050 : }
2051 4514 : rvcontext.root = root;
2052 4514 : rvcontext.targetlist = tlist;
2053 4514 : rvcontext.target_rte = rte;
2054 4514 : rvcontext.result_relation = 0;
2055 4514 : rvcontext.relids = NULL; /* can't be any lateral references here */
2056 4514 : rvcontext.nullinfo = NULL;
2057 4514 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2058 4514 : rvcontext.varno = varno;
2059 4514 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2060 : /* initialize cache array with indexes 0 .. length(tlist) */
2061 4514 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
2062 : sizeof(Node *));
2063 :
2064 : /*
2065 : * Replace all of the top query's references to the RTE's outputs with
2066 : * copies of the adjusted VALUES expressions, being careful not to replace
2067 : * any of the jointree structure. We can assume there's no outer joins or
2068 : * appendrels in the dummy Query that surrounds a VALUES RTE.
2069 : */
2070 4514 : perform_pullup_replace_vars(root, &rvcontext, NULL);
2071 :
2072 : /*
2073 : * There should be no appendrels to fix, nor any outer joins and hence no
2074 : * PlaceHolderVars.
2075 : */
2076 : Assert(root->append_rel_list == NIL);
2077 : Assert(root->join_info_list == NIL);
2078 : Assert(root->placeholder_list == NIL);
2079 :
2080 : /*
2081 : * Replace the VALUES RTE with a RESULT RTE. The VALUES RTE is the only
2082 : * rtable entry in the current query level, so this is easy.
2083 : */
2084 : Assert(list_length(parse->rtable) == 1);
2085 :
2086 : /* Create suitable RTE */
2087 4514 : rte = makeNode(RangeTblEntry);
2088 4514 : rte->rtekind = RTE_RESULT;
2089 4514 : rte->eref = makeAlias("*RESULT*", NIL);
2090 :
2091 : /* Replace rangetable */
2092 4514 : parse->rtable = list_make1(rte);
2093 :
2094 : /* We could manufacture a new RangeTblRef, but the one we have is fine */
2095 : Assert(varno == 1);
2096 :
2097 4514 : return jtnode;
2098 : }
2099 :
2100 : /*
2101 : * is_simple_values
2102 : * Check a VALUES RTE in the range table to see if it's simple enough
2103 : * to pull up into the parent query.
2104 : *
2105 : * rte is the RTE_VALUES RangeTblEntry to check.
2106 : */
2107 : static bool
2108 12812 : is_simple_values(PlannerInfo *root, RangeTblEntry *rte)
2109 : {
2110 : Assert(rte->rtekind == RTE_VALUES);
2111 :
2112 : /*
2113 : * There must be exactly one VALUES list, else it's not semantically
2114 : * correct to replace the VALUES RTE with a RESULT RTE, nor would we have
2115 : * a unique set of expressions to substitute into the parent query.
2116 : */
2117 12812 : if (list_length(rte->values_lists) != 1)
2118 8298 : return false;
2119 :
2120 : /*
2121 : * Because VALUES can't appear under an outer join (or at least, we won't
2122 : * try to pull it up if it does), we need not worry about LATERAL, nor
2123 : * about validity of PHVs for the VALUES' outputs.
2124 : */
2125 :
2126 : /*
2127 : * Don't pull up a VALUES that contains any set-returning or volatile
2128 : * functions. The considerations here are basically identical to the
2129 : * restrictions on a pull-able subquery's targetlist.
2130 : */
2131 9028 : if (expression_returns_set((Node *) rte->values_lists) ||
2132 4514 : contain_volatile_functions((Node *) rte->values_lists))
2133 0 : return false;
2134 :
2135 : /*
2136 : * Do not pull up a VALUES that's not the only RTE in its parent query.
2137 : * This is actually the only case that the parser will generate at the
2138 : * moment, and assuming this is true greatly simplifies
2139 : * pull_up_simple_values().
2140 : */
2141 4514 : if (list_length(root->parse->rtable) != 1 ||
2142 4514 : rte != (RangeTblEntry *) linitial(root->parse->rtable))
2143 0 : return false;
2144 :
2145 4514 : return true;
2146 : }
2147 :
2148 : /*
2149 : * pull_up_constant_function
2150 : * Pull up an RTE_FUNCTION expression that was simplified to a constant.
2151 : *
2152 : * jtnode is a RangeTblRef that has been identified as a FUNCTION RTE by
2153 : * pull_up_subqueries. If its expression is just a Const, hoist that value
2154 : * up into the parent query, and replace the RTE_FUNCTION with RTE_RESULT.
2155 : *
2156 : * In principle we could pull up any immutable expression, but we don't.
2157 : * That might result in multiple evaluations of the expression, which could
2158 : * be costly if it's not just a Const. Also, the main value of this is
2159 : * to let the constant participate in further const-folding, and of course
2160 : * that won't happen for a non-Const.
2161 : *
2162 : * The pulled-up value might need to be wrapped in a PlaceHolderVar if the
2163 : * RTE is below an outer join or is part of an appendrel; the extra
2164 : * parameters show whether that's needed.
2165 : */
2166 : static Node *
2167 52880 : pull_up_constant_function(PlannerInfo *root, Node *jtnode,
2168 : RangeTblEntry *rte,
2169 : AppendRelInfo *containing_appendrel)
2170 : {
2171 52880 : Query *parse = root->parse;
2172 : RangeTblFunction *rtf;
2173 : TypeFuncClass functypclass;
2174 : Oid funcrettype;
2175 : TupleDesc tupdesc;
2176 : pullup_replace_vars_context rvcontext;
2177 :
2178 : /* Fail if the RTE has ORDINALITY - we don't implement that here. */
2179 52880 : if (rte->funcordinality)
2180 922 : return jtnode;
2181 :
2182 : /* Fail if RTE isn't a single, simple Const expr */
2183 51958 : if (list_length(rte->functions) != 1)
2184 72 : return jtnode;
2185 51886 : rtf = linitial_node(RangeTblFunction, rte->functions);
2186 51886 : if (!IsA(rtf->funcexpr, Const))
2187 51514 : return jtnode;
2188 :
2189 : /*
2190 : * If the function's result is not a scalar, we punt. In principle we
2191 : * could break the composite constant value apart into per-column
2192 : * constants, but for now it seems not worth the work.
2193 : */
2194 372 : if (rtf->funccolcount != 1)
2195 30 : return jtnode; /* definitely composite */
2196 :
2197 : /* If it has a coldeflist, it certainly returns RECORD */
2198 342 : if (rtf->funccolnames != NIL)
2199 0 : return jtnode; /* must be a one-column RECORD type */
2200 :
2201 342 : functypclass = get_expr_result_type(rtf->funcexpr,
2202 : &funcrettype,
2203 : &tupdesc);
2204 342 : if (functypclass != TYPEFUNC_SCALAR)
2205 12 : return jtnode; /* must be a one-column composite type */
2206 :
2207 : /* Create context for applying pullup_replace_vars */
2208 330 : rvcontext.root = root;
2209 330 : rvcontext.targetlist = list_make1(makeTargetEntry((Expr *) rtf->funcexpr,
2210 : 1, /* resno */
2211 : NULL, /* resname */
2212 : false)); /* resjunk */
2213 330 : rvcontext.target_rte = rte;
2214 330 : rvcontext.result_relation = 0;
2215 :
2216 : /*
2217 : * Since this function was reduced to a Const, it doesn't contain any
2218 : * lateral references, even if it's marked as LATERAL. This means we
2219 : * don't need to fill relids or nullinfo.
2220 : */
2221 330 : rvcontext.relids = NULL;
2222 330 : rvcontext.nullinfo = NULL;
2223 :
2224 330 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2225 330 : rvcontext.varno = ((RangeTblRef *) jtnode)->rtindex;
2226 : /* this flag will be set below, if needed */
2227 330 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2228 : /* initialize cache array with indexes 0 .. length(tlist) */
2229 330 : rvcontext.rv_cache = palloc0((list_length(rvcontext.targetlist) + 1) *
2230 : sizeof(Node *));
2231 :
2232 : /*
2233 : * If the parent query uses grouping sets, we need a PlaceHolderVar for
2234 : * each expression of the subquery's targetlist items. (See comments in
2235 : * pull_up_simple_subquery().)
2236 : */
2237 330 : if (parse->groupingSets)
2238 0 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
2239 :
2240 : /*
2241 : * Replace all of the top query's references to the RTE's output with
2242 : * copies of the funcexpr, being careful not to replace any of the
2243 : * jointree structure.
2244 : */
2245 330 : perform_pullup_replace_vars(root, &rvcontext,
2246 : containing_appendrel);
2247 :
2248 : /*
2249 : * We don't need to bother with changing PlaceHolderVars in the parent
2250 : * query. Their references to the RT index are still good for now, and
2251 : * will get removed later if we're able to drop the RTE_RESULT.
2252 : */
2253 :
2254 : /*
2255 : * Convert the RTE to be RTE_RESULT type, signifying that we don't need to
2256 : * scan it anymore, and zero out RTE_FUNCTION-specific fields. Also make
2257 : * sure the RTE is not marked LATERAL, since elsewhere we don't expect
2258 : * RTE_RESULTs to be LATERAL.
2259 : */
2260 330 : rte->rtekind = RTE_RESULT;
2261 330 : rte->functions = NIL;
2262 330 : rte->lateral = false;
2263 :
2264 : /*
2265 : * We can reuse the RangeTblRef node.
2266 : */
2267 330 : return jtnode;
2268 : }
2269 :
2270 : /*
2271 : * is_simple_union_all
2272 : * Check a subquery to see if it's a simple UNION ALL.
2273 : *
2274 : * We require all the setops to be UNION ALL (no mixing) and there can't be
2275 : * any datatype coercions involved, ie, all the leaf queries must emit the
2276 : * same datatypes.
2277 : */
2278 : static bool
2279 22322 : is_simple_union_all(Query *subquery)
2280 : {
2281 : SetOperationStmt *topop;
2282 :
2283 : /* Let's just make sure it's a valid subselect ... */
2284 22322 : if (!IsA(subquery, Query) ||
2285 22322 : subquery->commandType != CMD_SELECT)
2286 0 : elog(ERROR, "subquery is bogus");
2287 :
2288 : /* Is it a set-operation query at all? */
2289 22322 : topop = castNode(SetOperationStmt, subquery->setOperations);
2290 22322 : if (!topop)
2291 16676 : return false;
2292 :
2293 : /* Can't handle ORDER BY, LIMIT/OFFSET, locking, or WITH */
2294 5646 : if (subquery->sortClause ||
2295 5582 : subquery->limitOffset ||
2296 5582 : subquery->limitCount ||
2297 5582 : subquery->rowMarks ||
2298 5582 : subquery->cteList)
2299 252 : return false;
2300 :
2301 : /* Recursively check the tree of set operations */
2302 5394 : return is_simple_union_all_recurse((Node *) topop, subquery,
2303 : topop->colTypes);
2304 : }
2305 :
2306 : static bool
2307 34272 : is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes)
2308 : {
2309 : /* Since this function recurses, it could be driven to stack overflow. */
2310 34272 : check_stack_depth();
2311 :
2312 34272 : if (IsA(setOp, RangeTblRef))
2313 : {
2314 17458 : RangeTblRef *rtr = (RangeTblRef *) setOp;
2315 17458 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
2316 17458 : Query *subquery = rte->subquery;
2317 :
2318 : Assert(subquery != NULL);
2319 :
2320 : /* Leaf nodes are OK if they match the toplevel column types */
2321 : /* We don't have to compare typmods or collations here */
2322 17458 : return tlist_same_datatypes(subquery->targetList, colTypes, true);
2323 : }
2324 16814 : else if (IsA(setOp, SetOperationStmt))
2325 : {
2326 16814 : SetOperationStmt *op = (SetOperationStmt *) setOp;
2327 :
2328 : /* Must be UNION ALL */
2329 16814 : if (op->op != SETOP_UNION || !op->all)
2330 5014 : return false;
2331 :
2332 : /* Recurse to check inputs */
2333 22914 : return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
2334 11114 : is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
2335 : }
2336 : else
2337 : {
2338 0 : elog(ERROR, "unrecognized node type: %d",
2339 : (int) nodeTag(setOp));
2340 : return false; /* keep compiler quiet */
2341 : }
2342 : }
2343 :
2344 : /*
2345 : * is_safe_append_member
2346 : * Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
2347 : * safe to pull up.
2348 : */
2349 : static bool
2350 18830 : is_safe_append_member(Query *subquery)
2351 : {
2352 : FromExpr *jtnode;
2353 :
2354 : /*
2355 : * It's only safe to pull up the child if its jointree contains exactly
2356 : * one RTE, else the AppendRelInfo data structure breaks. The one base RTE
2357 : * could be buried in several levels of FromExpr, however. Also, if the
2358 : * child's jointree is completely empty, we can pull up because
2359 : * pull_up_simple_subquery will insert a single RTE_RESULT RTE instead.
2360 : *
2361 : * Also, the child can't have any WHERE quals because there's no place to
2362 : * put them in an appendrel. (This is a bit annoying...) If we didn't
2363 : * need to check this, we'd just test whether get_relids_in_jointree()
2364 : * yields a singleton set, to be more consistent with the coding of
2365 : * fix_append_rel_relids().
2366 : */
2367 18830 : jtnode = subquery->jointree;
2368 : Assert(IsA(jtnode, FromExpr));
2369 : /* Check the completely-empty case */
2370 18830 : if (jtnode->fromlist == NIL && jtnode->quals == NULL)
2371 584 : return true;
2372 : /* Check the more general case */
2373 32084 : while (IsA(jtnode, FromExpr))
2374 : {
2375 18258 : if (jtnode->quals != NULL)
2376 4420 : return false;
2377 13838 : if (list_length(jtnode->fromlist) != 1)
2378 0 : return false;
2379 13838 : jtnode = linitial(jtnode->fromlist);
2380 : }
2381 13826 : if (!IsA(jtnode, RangeTblRef))
2382 1734 : return false;
2383 :
2384 12092 : return true;
2385 : }
2386 :
2387 : /*
2388 : * jointree_contains_lateral_outer_refs
2389 : * Check for disallowed lateral references in a jointree's quals
2390 : *
2391 : * If restricted is false, all level-1 Vars are allowed (but we still must
2392 : * search the jointree, since it might contain outer joins below which there
2393 : * will be restrictions). If restricted is true, return true when any qual
2394 : * in the jointree contains level-1 Vars coming from outside the rels listed
2395 : * in safe_upper_varnos.
2396 : */
2397 : static bool
2398 5184 : jointree_contains_lateral_outer_refs(PlannerInfo *root, Node *jtnode,
2399 : bool restricted,
2400 : Relids safe_upper_varnos)
2401 : {
2402 5184 : if (jtnode == NULL)
2403 0 : return false;
2404 5184 : if (IsA(jtnode, RangeTblRef))
2405 2410 : return false;
2406 2774 : else if (IsA(jtnode, FromExpr))
2407 : {
2408 2460 : FromExpr *f = (FromExpr *) jtnode;
2409 : ListCell *l;
2410 :
2411 : /* First, recurse to check child joins */
2412 4580 : foreach(l, f->fromlist)
2413 : {
2414 2144 : if (jointree_contains_lateral_outer_refs(root,
2415 2144 : lfirst(l),
2416 : restricted,
2417 : safe_upper_varnos))
2418 24 : return true;
2419 : }
2420 :
2421 : /* Then check the top-level quals */
2422 2436 : if (restricted &&
2423 1412 : !bms_is_subset(pull_varnos_of_level(root, f->quals, 1),
2424 : safe_upper_varnos))
2425 0 : return true;
2426 : }
2427 314 : else if (IsA(jtnode, JoinExpr))
2428 : {
2429 314 : JoinExpr *j = (JoinExpr *) jtnode;
2430 :
2431 : /*
2432 : * If this is an outer join, we mustn't allow any upper lateral
2433 : * references in or below it.
2434 : */
2435 314 : if (j->jointype != JOIN_INNER)
2436 : {
2437 158 : restricted = true;
2438 158 : safe_upper_varnos = NULL;
2439 : }
2440 :
2441 : /* Check the child joins */
2442 314 : if (jointree_contains_lateral_outer_refs(root,
2443 : j->larg,
2444 : restricted,
2445 : safe_upper_varnos))
2446 0 : return true;
2447 314 : if (jointree_contains_lateral_outer_refs(root,
2448 : j->rarg,
2449 : restricted,
2450 : safe_upper_varnos))
2451 0 : return true;
2452 :
2453 : /* Check the JOIN's qual clauses */
2454 314 : if (restricted &&
2455 290 : !bms_is_subset(pull_varnos_of_level(root, j->quals, 1),
2456 : safe_upper_varnos))
2457 24 : return true;
2458 : }
2459 : else
2460 0 : elog(ERROR, "unrecognized node type: %d",
2461 : (int) nodeTag(jtnode));
2462 2726 : return false;
2463 : }
2464 :
2465 : /*
2466 : * Perform pullup_replace_vars everyplace it's needed in the query tree.
2467 : *
2468 : * Caller has already filled *rvcontext with data describing what to
2469 : * substitute for Vars referencing the target subquery. In addition
2470 : * we need the identity of the containing appendrel if any.
2471 : */
2472 : static void
2473 42552 : perform_pullup_replace_vars(PlannerInfo *root,
2474 : pullup_replace_vars_context *rvcontext,
2475 : AppendRelInfo *containing_appendrel)
2476 : {
2477 42552 : Query *parse = root->parse;
2478 : ListCell *lc;
2479 :
2480 : /*
2481 : * If we are considering an appendrel child subquery (that is, a UNION ALL
2482 : * member query that we're pulling up), then the only part of the upper
2483 : * query that could reference the child yet is the translated_vars list of
2484 : * the associated AppendRelInfo. Furthermore, we do not want to force use
2485 : * of PHVs in the AppendRelInfo --- there isn't any outer join between.
2486 : */
2487 42552 : if (containing_appendrel)
2488 : {
2489 6230 : ReplaceWrapOption save_wrap_option = rvcontext->wrap_option;
2490 :
2491 6230 : rvcontext->wrap_option = REPLACE_WRAP_NONE;
2492 6230 : containing_appendrel->translated_vars = (List *)
2493 6230 : pullup_replace_vars((Node *) containing_appendrel->translated_vars,
2494 : rvcontext);
2495 6230 : rvcontext->wrap_option = save_wrap_option;
2496 6230 : return;
2497 : }
2498 :
2499 : /*
2500 : * Replace all of the top query's references to the subquery's outputs
2501 : * with copies of the adjusted subtlist items, being careful not to
2502 : * replace any of the jointree structure. (This'd be a lot cleaner if we
2503 : * could use query_tree_mutator.) We have to use PHVs in the targetList,
2504 : * returningList, and havingQual, since those are certainly above any
2505 : * outer join. replace_vars_in_jointree tracks its location in the
2506 : * jointree and uses PHVs or not appropriately.
2507 : */
2508 36322 : parse->targetList = (List *)
2509 36322 : pullup_replace_vars((Node *) parse->targetList, rvcontext);
2510 36322 : parse->returningList = (List *)
2511 36322 : pullup_replace_vars((Node *) parse->returningList, rvcontext);
2512 :
2513 36322 : if (parse->onConflict)
2514 : {
2515 44 : parse->onConflict->onConflictSet = (List *)
2516 22 : pullup_replace_vars((Node *) parse->onConflict->onConflictSet,
2517 : rvcontext);
2518 22 : parse->onConflict->onConflictWhere =
2519 22 : pullup_replace_vars(parse->onConflict->onConflictWhere,
2520 : rvcontext);
2521 :
2522 : /*
2523 : * We assume ON CONFLICT's arbiterElems, arbiterWhere, exclRelTlist
2524 : * can't contain any references to a subquery.
2525 : */
2526 : }
2527 36322 : if (parse->mergeActionList)
2528 : {
2529 3038 : foreach(lc, parse->mergeActionList)
2530 : {
2531 1814 : MergeAction *action = lfirst(lc);
2532 :
2533 1814 : action->qual = pullup_replace_vars(action->qual, rvcontext);
2534 1814 : action->targetList = (List *)
2535 1814 : pullup_replace_vars((Node *) action->targetList, rvcontext);
2536 : }
2537 : }
2538 36322 : parse->mergeJoinCondition = pullup_replace_vars(parse->mergeJoinCondition,
2539 : rvcontext);
2540 36322 : replace_vars_in_jointree((Node *) parse->jointree, rvcontext);
2541 : Assert(parse->setOperations == NULL);
2542 36316 : parse->havingQual = pullup_replace_vars(parse->havingQual, rvcontext);
2543 :
2544 : /*
2545 : * Replace references in the translated_vars lists of appendrels.
2546 : */
2547 36352 : foreach(lc, root->append_rel_list)
2548 : {
2549 36 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(lc);
2550 :
2551 36 : appinfo->translated_vars = (List *)
2552 36 : pullup_replace_vars((Node *) appinfo->translated_vars, rvcontext);
2553 : }
2554 :
2555 : /*
2556 : * Replace references in the joinaliasvars lists of join RTEs and the
2557 : * groupexprs list of group RTE.
2558 : */
2559 101248 : foreach(lc, parse->rtable)
2560 : {
2561 64932 : RangeTblEntry *otherrte = (RangeTblEntry *) lfirst(lc);
2562 :
2563 64932 : if (otherrte->rtekind == RTE_JOIN)
2564 6856 : otherrte->joinaliasvars = (List *)
2565 6856 : pullup_replace_vars((Node *) otherrte->joinaliasvars,
2566 : rvcontext);
2567 58076 : else if (otherrte->rtekind == RTE_GROUP)
2568 736 : otherrte->groupexprs = (List *)
2569 736 : pullup_replace_vars((Node *) otherrte->groupexprs,
2570 : rvcontext);
2571 : }
2572 : }
2573 :
2574 : /*
2575 : * Helper routine for perform_pullup_replace_vars: do pullup_replace_vars on
2576 : * every expression in the jointree, without changing the jointree structure
2577 : * itself. Ugly, but there's no other way...
2578 : */
2579 : static void
2580 94618 : replace_vars_in_jointree(Node *jtnode,
2581 : pullup_replace_vars_context *context)
2582 : {
2583 94618 : if (jtnode == NULL)
2584 0 : return;
2585 94618 : if (IsA(jtnode, RangeTblRef))
2586 : {
2587 : /*
2588 : * If the RangeTblRef refers to a LATERAL subquery (that isn't the
2589 : * same subquery we're pulling up), it might contain references to the
2590 : * target subquery, which we must replace. We drive this from the
2591 : * jointree scan, rather than a scan of the rtable, so that we can
2592 : * avoid processing no-longer-referenced RTEs.
2593 : */
2594 47508 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2595 :
2596 47508 : if (varno != context->varno) /* ignore target subquery itself */
2597 : {
2598 11186 : RangeTblEntry *rte = rt_fetch(varno, context->root->parse->rtable);
2599 :
2600 : Assert(rte != context->target_rte);
2601 11186 : if (rte->lateral)
2602 : {
2603 926 : switch (rte->rtekind)
2604 : {
2605 0 : case RTE_RELATION:
2606 : /* shouldn't be marked LATERAL unless tablesample */
2607 : Assert(rte->tablesample);
2608 0 : rte->tablesample = (TableSampleClause *)
2609 0 : pullup_replace_vars((Node *) rte->tablesample,
2610 : context);
2611 0 : break;
2612 450 : case RTE_SUBQUERY:
2613 450 : rte->subquery =
2614 450 : pullup_replace_vars_subquery(rte->subquery,
2615 : context);
2616 450 : break;
2617 368 : case RTE_FUNCTION:
2618 368 : rte->functions = (List *)
2619 368 : pullup_replace_vars((Node *) rte->functions,
2620 : context);
2621 368 : break;
2622 108 : case RTE_TABLEFUNC:
2623 108 : rte->tablefunc = (TableFunc *)
2624 108 : pullup_replace_vars((Node *) rte->tablefunc,
2625 : context);
2626 108 : break;
2627 0 : case RTE_VALUES:
2628 0 : rte->values_lists = (List *)
2629 0 : pullup_replace_vars((Node *) rte->values_lists,
2630 : context);
2631 0 : break;
2632 0 : case RTE_JOIN:
2633 : case RTE_CTE:
2634 : case RTE_NAMEDTUPLESTORE:
2635 : case RTE_RESULT:
2636 : case RTE_GROUP:
2637 : /* these shouldn't be marked LATERAL */
2638 : Assert(false);
2639 0 : break;
2640 : }
2641 : }
2642 : }
2643 : }
2644 47110 : else if (IsA(jtnode, FromExpr))
2645 : {
2646 39038 : FromExpr *f = (FromExpr *) jtnode;
2647 : ListCell *l;
2648 :
2649 81190 : foreach(l, f->fromlist)
2650 42152 : replace_vars_in_jointree(lfirst(l), context);
2651 39038 : f->quals = pullup_replace_vars(f->quals, context);
2652 : }
2653 8072 : else if (IsA(jtnode, JoinExpr))
2654 : {
2655 8072 : JoinExpr *j = (JoinExpr *) jtnode;
2656 8072 : ReplaceWrapOption save_wrap_option = context->wrap_option;
2657 :
2658 8072 : replace_vars_in_jointree(j->larg, context);
2659 8072 : replace_vars_in_jointree(j->rarg, context);
2660 :
2661 : /*
2662 : * Use PHVs within the join quals of a full join for variable-free
2663 : * expressions. Otherwise, we cannot identify which side of the join
2664 : * a pulled-up variable-free expression came from, which can lead to
2665 : * failure to make a plan at all because none of the quals appear to
2666 : * be mergeable or hashable conditions.
2667 : */
2668 8072 : if (j->jointype == JOIN_FULL)
2669 628 : context->wrap_option = REPLACE_WRAP_VARFREE;
2670 :
2671 8072 : j->quals = pullup_replace_vars(j->quals, context);
2672 :
2673 8072 : context->wrap_option = save_wrap_option;
2674 : }
2675 : else
2676 0 : elog(ERROR, "unrecognized node type: %d",
2677 : (int) nodeTag(jtnode));
2678 : }
2679 :
2680 : /*
2681 : * Apply pullup variable replacement throughout an expression tree
2682 : *
2683 : * Returns a modified copy of the tree, so this can't be used where we
2684 : * need to do in-place replacement.
2685 : */
2686 : static Node *
2687 211464 : pullup_replace_vars(Node *expr, pullup_replace_vars_context *context)
2688 : {
2689 211464 : return replace_rte_variables(expr,
2690 : context->varno, 0,
2691 : pullup_replace_vars_callback,
2692 : context,
2693 : context->outer_hasSubLinks);
2694 : }
2695 :
2696 : static Node *
2697 117744 : pullup_replace_vars_callback(Var *var,
2698 : replace_rte_variables_context *context)
2699 : {
2700 117744 : pullup_replace_vars_context *rcon = (pullup_replace_vars_context *) context->callback_arg;
2701 117744 : int varattno = var->varattno;
2702 : bool need_phv;
2703 : Node *newnode;
2704 :
2705 : /* System columns are not replaced. */
2706 117744 : if (varattno < InvalidAttrNumber)
2707 42 : return (Node *) copyObject(var);
2708 :
2709 : /*
2710 : * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
2711 : * varnullingrels (unless we find below that the replacement expression is
2712 : * a Var or PlaceHolderVar that we can just add the nullingrels to). We
2713 : * also need one if the caller has instructed us that certain expression
2714 : * replacements need to be wrapped for identification purposes.
2715 : */
2716 223554 : need_phv = (var->varnullingrels != NULL) ||
2717 105852 : (rcon->wrap_option != REPLACE_WRAP_NONE);
2718 :
2719 : /*
2720 : * If PlaceHolderVars are needed, we cache the modified expressions in
2721 : * rcon->rv_cache[]. This is not in hopes of any material speed gain
2722 : * within this function, but to avoid generating identical PHVs with
2723 : * different IDs. That would result in duplicate evaluations at runtime,
2724 : * and possibly prevent optimizations that rely on recognizing different
2725 : * references to the same subquery output as being equal(). So it's worth
2726 : * a bit of extra effort to avoid it.
2727 : *
2728 : * The cached items have phlevelsup = 0 and phnullingrels = NULL; we'll
2729 : * copy them and adjust those values for this reference site below.
2730 : */
2731 117702 : if (need_phv &&
2732 13816 : varattno >= InvalidAttrNumber &&
2733 13816 : varattno <= list_length(rcon->targetlist) &&
2734 13816 : rcon->rv_cache[varattno] != NULL)
2735 : {
2736 : /* Just copy the entry and fall through to adjust phlevelsup etc */
2737 2828 : newnode = copyObject(rcon->rv_cache[varattno]);
2738 : }
2739 : else
2740 : {
2741 : /*
2742 : * Generate the replacement expression. This takes care of expanding
2743 : * wholerow references and dealing with non-default varreturningtype.
2744 : */
2745 114874 : newnode = ReplaceVarFromTargetList(var,
2746 : rcon->target_rte,
2747 : rcon->targetlist,
2748 : rcon->result_relation,
2749 : REPLACEVARS_REPORT_ERROR,
2750 : 0);
2751 :
2752 : /* Insert PlaceHolderVar if needed */
2753 114874 : if (need_phv)
2754 : {
2755 : bool wrap;
2756 :
2757 10988 : if (rcon->wrap_option == REPLACE_WRAP_ALL)
2758 : {
2759 : /* Caller told us to wrap all expressions in a PlaceHolderVar */
2760 800 : wrap = true;
2761 : }
2762 10188 : else if (varattno == InvalidAttrNumber)
2763 : {
2764 : /*
2765 : * Insert PlaceHolderVar for whole-tuple reference. Notice
2766 : * that we are wrapping one PlaceHolderVar around the whole
2767 : * RowExpr, rather than putting one around each element of the
2768 : * row. This is because we need the expression to yield NULL,
2769 : * not ROW(NULL,NULL,...) when it is forced to null by an
2770 : * outer join.
2771 : */
2772 72 : wrap = true;
2773 : }
2774 10116 : else if (newnode && IsA(newnode, Var) &&
2775 8090 : ((Var *) newnode)->varlevelsup == 0)
2776 : {
2777 : /*
2778 : * Simple Vars always escape being wrapped, unless they are
2779 : * lateral references to something outside the subquery being
2780 : * pulled up and the referenced rel is not under the same
2781 : * lowest nulling outer join.
2782 : */
2783 8074 : wrap = false;
2784 8074 : if (rcon->target_rte->lateral &&
2785 1410 : !bms_is_member(((Var *) newnode)->varno, rcon->relids))
2786 : {
2787 132 : nullingrel_info *nullinfo = rcon->nullinfo;
2788 132 : int lvarno = ((Var *) newnode)->varno;
2789 :
2790 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2791 132 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2792 132 : nullinfo->nullingrels[lvarno]))
2793 108 : wrap = true;
2794 : }
2795 : }
2796 2042 : else if (newnode && IsA(newnode, PlaceHolderVar) &&
2797 180 : ((PlaceHolderVar *) newnode)->phlevelsup == 0)
2798 : {
2799 : /* The same rules apply for a PlaceHolderVar */
2800 180 : wrap = false;
2801 180 : if (rcon->target_rte->lateral &&
2802 48 : !bms_is_subset(((PlaceHolderVar *) newnode)->phrels,
2803 48 : rcon->relids))
2804 : {
2805 48 : nullingrel_info *nullinfo = rcon->nullinfo;
2806 48 : Relids lvarnos = ((PlaceHolderVar *) newnode)->phrels;
2807 : int lvarno;
2808 :
2809 48 : lvarno = -1;
2810 72 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2811 : {
2812 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2813 48 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2814 48 : nullinfo->nullingrels[lvarno]))
2815 : {
2816 24 : wrap = true;
2817 24 : break;
2818 : }
2819 : }
2820 : }
2821 : }
2822 : else
2823 : {
2824 : /*
2825 : * If the node contains Var(s) or PlaceHolderVar(s) of the
2826 : * subquery being pulled up, or of rels that are under the
2827 : * same lowest nulling outer join as the subquery, and does
2828 : * not contain any non-strict constructs, then instead of
2829 : * adding a PHV on top we can add the required nullingrels to
2830 : * those Vars/PHVs. (This is fundamentally a generalization
2831 : * of the above cases for bare Vars and PHVs.)
2832 : *
2833 : * This test is somewhat expensive, but it avoids pessimizing
2834 : * the plan in cases where the nullingrels get removed again
2835 : * later by outer join reduction.
2836 : *
2837 : * Note that we don't force wrapping of expressions containing
2838 : * lateral references, so long as they also contain Vars/PHVs
2839 : * of the subquery, or of rels that are under the same lowest
2840 : * nulling outer join as the subquery. This is okay because
2841 : * of the restriction to strict constructs: if those Vars/PHVs
2842 : * have been forced to NULL by an outer join then the end
2843 : * result of the expression will be NULL too, regardless of
2844 : * the lateral references. So it's not necessary to force the
2845 : * expression to be evaluated below the outer join. This can
2846 : * be a very valuable optimization, because it may allow us to
2847 : * avoid using a nested loop to pass the lateral reference
2848 : * down.
2849 : *
2850 : * This analysis could be tighter: in particular, a non-strict
2851 : * construct hidden within a lower-level PlaceHolderVar is not
2852 : * reason to add another PHV. But for now it doesn't seem
2853 : * worth the code to be more exact. This is also why it's
2854 : * preferable to handle bare PHVs in the above branch, rather
2855 : * than this branch. We also prefer to handle bare Vars in a
2856 : * separate branch, as it's cheaper this way and parallels the
2857 : * handling of PHVs.
2858 : *
2859 : * For a LATERAL subquery, we have to check the actual var
2860 : * membership of the node, but if it's non-lateral then any
2861 : * level-zero var must belong to the subquery.
2862 : */
2863 1862 : bool contain_nullable_vars = false;
2864 :
2865 1862 : if (!rcon->target_rte->lateral)
2866 : {
2867 1634 : if (contain_vars_of_level(newnode, 0))
2868 534 : contain_nullable_vars = true;
2869 : }
2870 : else
2871 : {
2872 : Relids all_varnos;
2873 :
2874 228 : all_varnos = pull_varnos(rcon->root, newnode);
2875 228 : if (bms_overlap(all_varnos, rcon->relids))
2876 132 : contain_nullable_vars = true;
2877 : else
2878 : {
2879 96 : nullingrel_info *nullinfo = rcon->nullinfo;
2880 : int varno;
2881 :
2882 96 : varno = -1;
2883 180 : while ((varno = bms_next_member(all_varnos, varno)) >= 0)
2884 : {
2885 : Assert(varno > 0 && varno <= nullinfo->rtlength);
2886 108 : if (bms_is_subset(nullinfo->nullingrels[rcon->varno],
2887 108 : nullinfo->nullingrels[varno]))
2888 : {
2889 24 : contain_nullable_vars = true;
2890 24 : break;
2891 : }
2892 : }
2893 : }
2894 : }
2895 :
2896 1862 : if (contain_nullable_vars &&
2897 690 : !contain_nonstrict_functions(newnode))
2898 : {
2899 : /* No wrap needed */
2900 288 : wrap = false;
2901 : }
2902 : else
2903 : {
2904 : /* Else wrap it in a PlaceHolderVar */
2905 1574 : wrap = true;
2906 : }
2907 : }
2908 :
2909 10988 : if (wrap)
2910 : {
2911 : newnode = (Node *)
2912 2578 : make_placeholder_expr(rcon->root,
2913 : (Expr *) newnode,
2914 : bms_make_singleton(rcon->varno));
2915 :
2916 : /*
2917 : * Cache it if possible (ie, if the attno is in range, which
2918 : * it probably always should be).
2919 : */
2920 5156 : if (varattno >= InvalidAttrNumber &&
2921 2578 : varattno <= list_length(rcon->targetlist))
2922 2578 : rcon->rv_cache[varattno] = copyObject(newnode);
2923 : }
2924 : }
2925 : }
2926 :
2927 : /* Propagate any varnullingrels into the replacement expression */
2928 117702 : if (var->varnullingrels != NULL)
2929 : {
2930 11850 : if (IsA(newnode, Var))
2931 : {
2932 7476 : Var *newvar = (Var *) newnode;
2933 :
2934 : Assert(newvar->varlevelsup == 0);
2935 7476 : newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
2936 7476 : var->varnullingrels);
2937 : }
2938 4374 : else if (IsA(newnode, PlaceHolderVar))
2939 : {
2940 4086 : PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
2941 :
2942 : Assert(newphv->phlevelsup == 0);
2943 4086 : newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
2944 4086 : var->varnullingrels);
2945 : }
2946 : else
2947 : {
2948 : /*
2949 : * There should be Vars/PHVs within the expression that we can
2950 : * modify. Vars/PHVs of the subquery should have the full
2951 : * var->varnullingrels added to them, but if there are lateral
2952 : * references within the expression, those must be marked with
2953 : * only the nullingrels that potentially apply to them. (This
2954 : * corresponds to the fact that the expression will now be
2955 : * evaluated at the join level of the Var that we are replacing:
2956 : * the lateral references may have bubbled up through fewer outer
2957 : * joins than the subquery's Vars have. Per the discussion above,
2958 : * we'll still get the right answers.) That relid set could be
2959 : * different for different lateral relations, so we have to do
2960 : * this work for each one.
2961 : *
2962 : * (Currently, the restrictions in is_simple_subquery() mean that
2963 : * at most we have to remove the lowest outer join's relid from
2964 : * the nullingrels of a lateral reference. However, we might
2965 : * relax those restrictions someday, so let's do this right.)
2966 : */
2967 288 : if (rcon->target_rte->lateral)
2968 : {
2969 84 : nullingrel_info *nullinfo = rcon->nullinfo;
2970 : Relids lvarnos;
2971 : int lvarno;
2972 :
2973 : /*
2974 : * Identify lateral varnos used within newnode. We must do
2975 : * this before injecting var->varnullingrels into the tree.
2976 : */
2977 84 : lvarnos = pull_varnos(rcon->root, newnode);
2978 84 : lvarnos = bms_del_members(lvarnos, rcon->relids);
2979 : /* For each one, add relevant nullingrels if any */
2980 84 : lvarno = -1;
2981 168 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2982 : {
2983 : Relids lnullingrels;
2984 :
2985 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2986 84 : lnullingrels = bms_intersect(var->varnullingrels,
2987 84 : nullinfo->nullingrels[lvarno]);
2988 84 : if (!bms_is_empty(lnullingrels))
2989 48 : newnode = add_nulling_relids(newnode,
2990 48 : bms_make_singleton(lvarno),
2991 : lnullingrels);
2992 : }
2993 : }
2994 :
2995 : /* Finally, deal with Vars/PHVs of the subquery itself */
2996 288 : newnode = add_nulling_relids(newnode,
2997 288 : rcon->relids,
2998 288 : var->varnullingrels);
2999 : /* Assert we did put the varnullingrels into the expression */
3000 : Assert(bms_is_subset(var->varnullingrels,
3001 : pull_varnos(rcon->root, newnode)));
3002 : }
3003 : }
3004 :
3005 : /* Must adjust varlevelsup if replaced Var is within a subquery */
3006 117702 : if (var->varlevelsup > 0)
3007 1212 : IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
3008 :
3009 117702 : return newnode;
3010 : }
3011 :
3012 : /*
3013 : * Apply pullup variable replacement to a subquery
3014 : *
3015 : * This needs to be different from pullup_replace_vars() because
3016 : * replace_rte_variables will think that it shouldn't increment sublevels_up
3017 : * before entering the Query; so we need to call it with sublevels_up == 1.
3018 : */
3019 : static Query *
3020 450 : pullup_replace_vars_subquery(Query *query,
3021 : pullup_replace_vars_context *context)
3022 : {
3023 : Assert(IsA(query, Query));
3024 450 : return (Query *) replace_rte_variables((Node *) query,
3025 : context->varno, 1,
3026 : pullup_replace_vars_callback,
3027 : context,
3028 : NULL);
3029 : }
3030 :
3031 :
3032 : /*
3033 : * flatten_simple_union_all
3034 : * Try to optimize top-level UNION ALL structure into an appendrel
3035 : *
3036 : * If a query's setOperations tree consists entirely of simple UNION ALL
3037 : * operations, flatten it into an append relation, which we can process more
3038 : * intelligently than the general setops case. Otherwise, do nothing.
3039 : *
3040 : * In most cases, this can succeed only for a top-level query, because for a
3041 : * subquery in FROM, the parent query's invocation of pull_up_subqueries would
3042 : * already have flattened the UNION via pull_up_simple_union_all. But there
3043 : * are a few cases we can support here but not in that code path, for example
3044 : * when the subquery also contains ORDER BY.
3045 : */
3046 : void
3047 6898 : flatten_simple_union_all(PlannerInfo *root)
3048 : {
3049 6898 : Query *parse = root->parse;
3050 : SetOperationStmt *topop;
3051 : Node *leftmostjtnode;
3052 : int leftmostRTI;
3053 : RangeTblEntry *leftmostRTE;
3054 : int childRTI;
3055 : RangeTblEntry *childRTE;
3056 : RangeTblRef *rtr;
3057 :
3058 : /* Shouldn't be called unless query has setops */
3059 6898 : topop = castNode(SetOperationStmt, parse->setOperations);
3060 : Assert(topop);
3061 :
3062 : /* Can't optimize away a recursive UNION */
3063 6898 : if (root->hasRecursion)
3064 6116 : return;
3065 :
3066 : /*
3067 : * Recursively check the tree of set operations. If not all UNION ALL
3068 : * with identical column types, punt.
3069 : */
3070 5964 : if (!is_simple_union_all_recurse((Node *) topop, parse, topop->colTypes))
3071 5182 : return;
3072 :
3073 : /*
3074 : * Locate the leftmost leaf query in the setops tree. The upper query's
3075 : * Vars all refer to this RTE (see transformSetOperationStmt).
3076 : */
3077 782 : leftmostjtnode = topop->larg;
3078 1182 : while (leftmostjtnode && IsA(leftmostjtnode, SetOperationStmt))
3079 400 : leftmostjtnode = ((SetOperationStmt *) leftmostjtnode)->larg;
3080 : Assert(leftmostjtnode && IsA(leftmostjtnode, RangeTblRef));
3081 782 : leftmostRTI = ((RangeTblRef *) leftmostjtnode)->rtindex;
3082 782 : leftmostRTE = rt_fetch(leftmostRTI, parse->rtable);
3083 : Assert(leftmostRTE->rtekind == RTE_SUBQUERY);
3084 :
3085 : /*
3086 : * Make a copy of the leftmost RTE and add it to the rtable. This copy
3087 : * will represent the leftmost leaf query in its capacity as a member of
3088 : * the appendrel. The original will represent the appendrel as a whole.
3089 : * (We must do things this way because the upper query's Vars have to be
3090 : * seen as referring to the whole appendrel.)
3091 : */
3092 782 : childRTE = copyObject(leftmostRTE);
3093 782 : parse->rtable = lappend(parse->rtable, childRTE);
3094 782 : childRTI = list_length(parse->rtable);
3095 :
3096 : /* Modify the setops tree to reference the child copy */
3097 782 : ((RangeTblRef *) leftmostjtnode)->rtindex = childRTI;
3098 :
3099 : /* Modify the formerly-leftmost RTE to mark it as an appendrel parent */
3100 782 : leftmostRTE->inh = true;
3101 :
3102 : /*
3103 : * Form a RangeTblRef for the appendrel, and insert it into FROM. The top
3104 : * Query of a setops tree should have had an empty FromClause initially.
3105 : */
3106 782 : rtr = makeNode(RangeTblRef);
3107 782 : rtr->rtindex = leftmostRTI;
3108 : Assert(parse->jointree->fromlist == NIL);
3109 782 : parse->jointree->fromlist = list_make1(rtr);
3110 :
3111 : /*
3112 : * Now pretend the query has no setops. We must do this before trying to
3113 : * do subquery pullup, because of Assert in pull_up_simple_subquery.
3114 : */
3115 782 : parse->setOperations = NULL;
3116 :
3117 : /*
3118 : * Build AppendRelInfo information, and apply pull_up_subqueries to the
3119 : * leaf queries of the UNION ALL. (We must do that now because they
3120 : * weren't previously referenced by the jointree, and so were missed by
3121 : * the main invocation of pull_up_subqueries.)
3122 : */
3123 782 : pull_up_union_leaf_queries((Node *) topop, root, leftmostRTI, parse, 0);
3124 : }
3125 :
3126 :
3127 : /*
3128 : * reduce_outer_joins
3129 : * Attempt to reduce outer joins to plain inner joins.
3130 : *
3131 : * The idea here is that given a query like
3132 : * SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
3133 : * we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
3134 : * is strict. The strict operator will always return NULL, causing the outer
3135 : * WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
3136 : * columns. Therefore, there's no need for the join to produce null-extended
3137 : * rows in the first place --- which makes it a plain join not an outer join.
3138 : * (This scenario may not be very likely in a query written out by hand, but
3139 : * it's reasonably likely when pushing quals down into complex views.)
3140 : *
3141 : * More generally, an outer join can be reduced in strength if there is a
3142 : * strict qual above it in the qual tree that constrains a Var from the
3143 : * nullable side of the join to be non-null. (For FULL joins this applies
3144 : * to each side separately.)
3145 : *
3146 : * Another transformation we apply here is to recognize cases like
3147 : * SELECT ... FROM a LEFT JOIN b ON (a.x = b.y) WHERE b.y IS NULL;
3148 : * If the join clause is strict for b.y, then only null-extended rows could
3149 : * pass the upper WHERE, and we can conclude that what the query is really
3150 : * specifying is an anti-semijoin. We change the join type from JOIN_LEFT
3151 : * to JOIN_ANTI. The IS NULL clause then becomes redundant, and must be
3152 : * removed to prevent bogus selectivity calculations, but we leave it to
3153 : * distribute_qual_to_rels to get rid of such clauses.
3154 : *
3155 : * Also, we get rid of JOIN_RIGHT cases by flipping them around to become
3156 : * JOIN_LEFT. This saves some code here and in some later planner routines;
3157 : * the main benefit is to reduce the number of jointypes that can appear in
3158 : * SpecialJoinInfo nodes. Note that we can still generate Paths and Plans
3159 : * that use JOIN_RIGHT (or JOIN_RIGHT_ANTI) by switching the inputs again.
3160 : *
3161 : * To ease recognition of strict qual clauses, we require this routine to be
3162 : * run after expression preprocessing (i.e., qual canonicalization and JOIN
3163 : * alias-var expansion).
3164 : */
3165 : void
3166 34174 : reduce_outer_joins(PlannerInfo *root)
3167 : {
3168 : reduce_outer_joins_pass1_state *state1;
3169 : reduce_outer_joins_pass2_state state2;
3170 : ListCell *lc;
3171 :
3172 : /*
3173 : * To avoid doing strictness checks on more quals than necessary, we want
3174 : * to stop descending the jointree as soon as there are no outer joins
3175 : * below our current point. This consideration forces a two-pass process.
3176 : * The first pass gathers information about which base rels appear below
3177 : * each side of each join clause, and about whether there are outer
3178 : * join(s) below each side of each join clause. The second pass examines
3179 : * qual clauses and changes join types as it descends the tree.
3180 : */
3181 34174 : state1 = reduce_outer_joins_pass1((Node *) root->parse->jointree);
3182 :
3183 : /* planner.c shouldn't have called me if no outer joins */
3184 34174 : if (state1 == NULL || !state1->contains_outer)
3185 0 : elog(ERROR, "so where are the outer joins?");
3186 :
3187 34174 : state2.inner_reduced = NULL;
3188 34174 : state2.partial_reduced = NIL;
3189 :
3190 34174 : reduce_outer_joins_pass2((Node *) root->parse->jointree,
3191 : state1, &state2,
3192 : root, NULL, NIL);
3193 :
3194 : /*
3195 : * If we successfully reduced the strength of any outer joins, we must
3196 : * remove references to those joins as nulling rels. This is handled as
3197 : * an additional pass, for simplicity and because we can handle all
3198 : * fully-reduced joins in a single pass over the parse tree.
3199 : */
3200 34174 : if (!bms_is_empty(state2.inner_reduced))
3201 : {
3202 1882 : root->parse = (Query *)
3203 1882 : remove_nulling_relids((Node *) root->parse,
3204 1882 : state2.inner_reduced,
3205 : NULL);
3206 : /* There could be references in the append_rel_list, too */
3207 1882 : root->append_rel_list = (List *)
3208 1882 : remove_nulling_relids((Node *) root->append_rel_list,
3209 1882 : state2.inner_reduced,
3210 : NULL);
3211 : }
3212 :
3213 : /*
3214 : * Partially-reduced full joins have to be done one at a time, since
3215 : * they'll each need a different setting of except_relids.
3216 : */
3217 34224 : foreach(lc, state2.partial_reduced)
3218 : {
3219 50 : reduce_outer_joins_partial_state *statep = lfirst(lc);
3220 50 : Relids full_join_relids = bms_make_singleton(statep->full_join_rti);
3221 :
3222 50 : root->parse = (Query *)
3223 50 : remove_nulling_relids((Node *) root->parse,
3224 : full_join_relids,
3225 50 : statep->unreduced_side);
3226 50 : root->append_rel_list = (List *)
3227 50 : remove_nulling_relids((Node *) root->append_rel_list,
3228 : full_join_relids,
3229 50 : statep->unreduced_side);
3230 : }
3231 34174 : }
3232 :
3233 : /*
3234 : * reduce_outer_joins_pass1 - phase 1 data collection
3235 : *
3236 : * Returns a state node describing the given jointree node.
3237 : */
3238 : static reduce_outer_joins_pass1_state *
3239 194652 : reduce_outer_joins_pass1(Node *jtnode)
3240 : {
3241 : reduce_outer_joins_pass1_state *result;
3242 :
3243 : result = (reduce_outer_joins_pass1_state *)
3244 194652 : palloc(sizeof(reduce_outer_joins_pass1_state));
3245 194652 : result->relids = NULL;
3246 194652 : result->contains_outer = false;
3247 194652 : result->sub_states = NIL;
3248 :
3249 194652 : if (jtnode == NULL)
3250 0 : return result;
3251 194652 : if (IsA(jtnode, RangeTblRef))
3252 : {
3253 97096 : int varno = ((RangeTblRef *) jtnode)->rtindex;
3254 :
3255 97096 : result->relids = bms_make_singleton(varno);
3256 : }
3257 97556 : else if (IsA(jtnode, FromExpr))
3258 : {
3259 37460 : FromExpr *f = (FromExpr *) jtnode;
3260 : ListCell *l;
3261 :
3262 77746 : foreach(l, f->fromlist)
3263 : {
3264 : reduce_outer_joins_pass1_state *sub_state;
3265 :
3266 40286 : sub_state = reduce_outer_joins_pass1(lfirst(l));
3267 80572 : result->relids = bms_add_members(result->relids,
3268 40286 : sub_state->relids);
3269 40286 : result->contains_outer |= sub_state->contains_outer;
3270 40286 : result->sub_states = lappend(result->sub_states, sub_state);
3271 : }
3272 : }
3273 60096 : else if (IsA(jtnode, JoinExpr))
3274 : {
3275 60096 : JoinExpr *j = (JoinExpr *) jtnode;
3276 : reduce_outer_joins_pass1_state *sub_state;
3277 :
3278 : /* join's own RT index is not wanted in result->relids */
3279 60096 : if (IS_OUTER_JOIN(j->jointype))
3280 49110 : result->contains_outer = true;
3281 :
3282 60096 : sub_state = reduce_outer_joins_pass1(j->larg);
3283 120192 : result->relids = bms_add_members(result->relids,
3284 60096 : sub_state->relids);
3285 60096 : result->contains_outer |= sub_state->contains_outer;
3286 60096 : result->sub_states = lappend(result->sub_states, sub_state);
3287 :
3288 60096 : sub_state = reduce_outer_joins_pass1(j->rarg);
3289 120192 : result->relids = bms_add_members(result->relids,
3290 60096 : sub_state->relids);
3291 60096 : result->contains_outer |= sub_state->contains_outer;
3292 60096 : result->sub_states = lappend(result->sub_states, sub_state);
3293 : }
3294 : else
3295 0 : elog(ERROR, "unrecognized node type: %d",
3296 : (int) nodeTag(jtnode));
3297 194652 : return result;
3298 : }
3299 :
3300 : /*
3301 : * reduce_outer_joins_pass2 - phase 2 processing
3302 : *
3303 : * jtnode: current jointree node
3304 : * state1: state data collected by phase 1 for this node
3305 : * state2: where to accumulate info about successfully-reduced joins
3306 : * root: toplevel planner state
3307 : * nonnullable_rels: set of base relids forced non-null by upper quals
3308 : * forced_null_vars: multibitmapset of Vars forced null by upper quals
3309 : *
3310 : * Returns info in state2 about outer joins that were successfully simplified.
3311 : * Joins that were fully reduced to inner joins are all added to
3312 : * state2->inner_reduced. If a full join is reduced to a left join,
3313 : * it needs its own entry in state2->partial_reduced, since that will
3314 : * require custom processing to remove only the correct nullingrel markers.
3315 : */
3316 : static void
3317 85332 : reduce_outer_joins_pass2(Node *jtnode,
3318 : reduce_outer_joins_pass1_state *state1,
3319 : reduce_outer_joins_pass2_state *state2,
3320 : PlannerInfo *root,
3321 : Relids nonnullable_rels,
3322 : List *forced_null_vars)
3323 : {
3324 : /*
3325 : * pass 2 should never descend as far as an empty subnode or base rel,
3326 : * because it's only called on subtrees marked as contains_outer.
3327 : */
3328 85332 : if (jtnode == NULL)
3329 0 : elog(ERROR, "reached empty jointree");
3330 85332 : if (IsA(jtnode, RangeTblRef))
3331 0 : elog(ERROR, "reached base rel");
3332 85332 : else if (IsA(jtnode, FromExpr))
3333 : {
3334 35604 : FromExpr *f = (FromExpr *) jtnode;
3335 : ListCell *l;
3336 : ListCell *s;
3337 : Relids pass_nonnullable_rels;
3338 : List *pass_forced_null_vars;
3339 :
3340 : /* Scan quals to see if we can add any constraints */
3341 35604 : pass_nonnullable_rels = find_nonnullable_rels(f->quals);
3342 35604 : pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels,
3343 : nonnullable_rels);
3344 35604 : pass_forced_null_vars = find_forced_null_vars(f->quals);
3345 35604 : pass_forced_null_vars = mbms_add_members(pass_forced_null_vars,
3346 : forced_null_vars);
3347 : /* And recurse --- but only into interesting subtrees */
3348 : Assert(list_length(f->fromlist) == list_length(state1->sub_states));
3349 73872 : forboth(l, f->fromlist, s, state1->sub_states)
3350 : {
3351 38268 : reduce_outer_joins_pass1_state *sub_state = lfirst(s);
3352 :
3353 38268 : if (sub_state->contains_outer)
3354 35634 : reduce_outer_joins_pass2(lfirst(l), sub_state,
3355 : state2, root,
3356 : pass_nonnullable_rels,
3357 : pass_forced_null_vars);
3358 : }
3359 35604 : bms_free(pass_nonnullable_rels);
3360 : /* can't so easily clean up var lists, unfortunately */
3361 : }
3362 49728 : else if (IsA(jtnode, JoinExpr))
3363 : {
3364 49728 : JoinExpr *j = (JoinExpr *) jtnode;
3365 49728 : int rtindex = j->rtindex;
3366 49728 : JoinType jointype = j->jointype;
3367 49728 : reduce_outer_joins_pass1_state *left_state = linitial(state1->sub_states);
3368 49728 : reduce_outer_joins_pass1_state *right_state = lsecond(state1->sub_states);
3369 :
3370 : /* Can we simplify this join? */
3371 49728 : switch (jointype)
3372 : {
3373 556 : case JOIN_INNER:
3374 556 : break;
3375 46380 : case JOIN_LEFT:
3376 46380 : if (bms_overlap(nonnullable_rels, right_state->relids))
3377 1940 : jointype = JOIN_INNER;
3378 46380 : break;
3379 1208 : case JOIN_RIGHT:
3380 1208 : if (bms_overlap(nonnullable_rels, left_state->relids))
3381 80 : jointype = JOIN_INNER;
3382 1208 : break;
3383 1096 : case JOIN_FULL:
3384 1096 : if (bms_overlap(nonnullable_rels, left_state->relids))
3385 : {
3386 24 : if (bms_overlap(nonnullable_rels, right_state->relids))
3387 12 : jointype = JOIN_INNER;
3388 : else
3389 : {
3390 12 : jointype = JOIN_LEFT;
3391 : /* Also report partial reduction in state2 */
3392 12 : report_reduced_full_join(state2, rtindex,
3393 : right_state->relids);
3394 : }
3395 : }
3396 : else
3397 : {
3398 1072 : if (bms_overlap(nonnullable_rels, right_state->relids))
3399 : {
3400 38 : jointype = JOIN_RIGHT;
3401 : /* Also report partial reduction in state2 */
3402 38 : report_reduced_full_join(state2, rtindex,
3403 : left_state->relids);
3404 : }
3405 : }
3406 1096 : break;
3407 488 : case JOIN_SEMI:
3408 : case JOIN_ANTI:
3409 :
3410 : /*
3411 : * These could only have been introduced by pull_up_sublinks,
3412 : * so there's no way that upper quals could refer to their
3413 : * righthand sides, and no point in checking. We don't expect
3414 : * to see JOIN_RIGHT_SEMI or JOIN_RIGHT_ANTI yet.
3415 : */
3416 488 : break;
3417 0 : default:
3418 0 : elog(ERROR, "unrecognized join type: %d",
3419 : (int) jointype);
3420 : break;
3421 : }
3422 :
3423 : /*
3424 : * Convert JOIN_RIGHT to JOIN_LEFT. Note that in the case where we
3425 : * reduced JOIN_FULL to JOIN_RIGHT, this will mean the JoinExpr no
3426 : * longer matches the internal ordering of any CoalesceExpr's built to
3427 : * represent merged join variables. We don't care about that at
3428 : * present, but be wary of it ...
3429 : */
3430 49728 : if (jointype == JOIN_RIGHT)
3431 : {
3432 : Node *tmparg;
3433 :
3434 1166 : tmparg = j->larg;
3435 1166 : j->larg = j->rarg;
3436 1166 : j->rarg = tmparg;
3437 1166 : jointype = JOIN_LEFT;
3438 1166 : right_state = linitial(state1->sub_states);
3439 1166 : left_state = lsecond(state1->sub_states);
3440 : }
3441 :
3442 : /*
3443 : * See if we can reduce JOIN_LEFT to JOIN_ANTI. This is the case if
3444 : * the join's own quals are strict for any var that was forced null by
3445 : * higher qual levels. NOTE: there are other ways that we could
3446 : * detect an anti-join, in particular if we were to check whether Vars
3447 : * coming from the RHS must be non-null because of table constraints.
3448 : * That seems complicated and expensive though (in particular, one
3449 : * would have to be wary of lower outer joins). For the moment this
3450 : * seems sufficient.
3451 : */
3452 49728 : if (jointype == JOIN_LEFT)
3453 : {
3454 : List *nonnullable_vars;
3455 : Bitmapset *overlap;
3456 :
3457 : /* Find Vars in j->quals that must be non-null in joined rows */
3458 45618 : nonnullable_vars = find_nonnullable_vars(j->quals);
3459 :
3460 : /*
3461 : * It's not sufficient to check whether nonnullable_vars and
3462 : * forced_null_vars overlap: we need to know if the overlap
3463 : * includes any RHS variables.
3464 : */
3465 45618 : overlap = mbms_overlap_sets(nonnullable_vars, forced_null_vars);
3466 45618 : if (bms_overlap(overlap, right_state->relids))
3467 1154 : jointype = JOIN_ANTI;
3468 : }
3469 :
3470 : /*
3471 : * Apply the jointype change, if any, to both jointree node and RTE.
3472 : * Also, if we changed an RTE to INNER, add its RTI to inner_reduced.
3473 : */
3474 49728 : if (rtindex && jointype != j->jointype)
3475 : {
3476 4364 : RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
3477 :
3478 : Assert(rte->rtekind == RTE_JOIN);
3479 : Assert(rte->jointype == j->jointype);
3480 4364 : rte->jointype = jointype;
3481 4364 : if (jointype == JOIN_INNER)
3482 2032 : state2->inner_reduced = bms_add_member(state2->inner_reduced,
3483 : rtindex);
3484 : }
3485 49728 : j->jointype = jointype;
3486 :
3487 : /* Only recurse if there's more to do below here */
3488 49728 : if (left_state->contains_outer || right_state->contains_outer)
3489 : {
3490 : Relids local_nonnullable_rels;
3491 : List *local_forced_null_vars;
3492 : Relids pass_nonnullable_rels;
3493 : List *pass_forced_null_vars;
3494 :
3495 : /*
3496 : * If this join is (now) inner, we can add any constraints its
3497 : * quals provide to those we got from above. But if it is outer,
3498 : * we can pass down the local constraints only into the nullable
3499 : * side, because an outer join never eliminates any rows from its
3500 : * non-nullable side. Also, there is no point in passing upper
3501 : * constraints into the nullable side, since if there were any
3502 : * we'd have been able to reduce the join. (In the case of upper
3503 : * forced-null constraints, we *must not* pass them into the
3504 : * nullable side --- they either applied here, or not.) The upshot
3505 : * is that we pass either the local or the upper constraints,
3506 : * never both, to the children of an outer join.
3507 : *
3508 : * Note that a SEMI join works like an inner join here: it's okay
3509 : * to pass down both local and upper constraints. (There can't be
3510 : * any upper constraints affecting its inner side, but it's not
3511 : * worth having a separate code path to avoid passing them.)
3512 : *
3513 : * At a FULL join we just punt and pass nothing down --- is it
3514 : * possible to be smarter?
3515 : */
3516 15456 : if (jointype != JOIN_FULL)
3517 : {
3518 15320 : local_nonnullable_rels = find_nonnullable_rels(j->quals);
3519 15320 : local_forced_null_vars = find_forced_null_vars(j->quals);
3520 15320 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3521 : {
3522 : /* OK to merge upper and local constraints */
3523 1010 : local_nonnullable_rels = bms_add_members(local_nonnullable_rels,
3524 : nonnullable_rels);
3525 1010 : local_forced_null_vars = mbms_add_members(local_forced_null_vars,
3526 : forced_null_vars);
3527 : }
3528 : }
3529 : else
3530 : {
3531 : /* no use in calculating these */
3532 136 : local_nonnullable_rels = NULL;
3533 136 : local_forced_null_vars = NIL;
3534 : }
3535 :
3536 15456 : if (left_state->contains_outer)
3537 : {
3538 14714 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3539 : {
3540 : /* pass union of local and upper constraints */
3541 798 : pass_nonnullable_rels = local_nonnullable_rels;
3542 798 : pass_forced_null_vars = local_forced_null_vars;
3543 : }
3544 13916 : else if (jointype != JOIN_FULL) /* ie, LEFT or ANTI */
3545 : {
3546 : /* can't pass local constraints to non-nullable side */
3547 13808 : pass_nonnullable_rels = nonnullable_rels;
3548 13808 : pass_forced_null_vars = forced_null_vars;
3549 : }
3550 : else
3551 : {
3552 : /* no constraints pass through JOIN_FULL */
3553 108 : pass_nonnullable_rels = NULL;
3554 108 : pass_forced_null_vars = NIL;
3555 : }
3556 14714 : reduce_outer_joins_pass2(j->larg, left_state,
3557 : state2, root,
3558 : pass_nonnullable_rels,
3559 : pass_forced_null_vars);
3560 : }
3561 :
3562 15456 : if (right_state->contains_outer)
3563 : {
3564 810 : if (jointype != JOIN_FULL) /* ie, INNER/LEFT/SEMI/ANTI */
3565 : {
3566 : /* pass appropriate constraints, per comment above */
3567 782 : pass_nonnullable_rels = local_nonnullable_rels;
3568 782 : pass_forced_null_vars = local_forced_null_vars;
3569 : }
3570 : else
3571 : {
3572 : /* no constraints pass through JOIN_FULL */
3573 28 : pass_nonnullable_rels = NULL;
3574 28 : pass_forced_null_vars = NIL;
3575 : }
3576 810 : reduce_outer_joins_pass2(j->rarg, right_state,
3577 : state2, root,
3578 : pass_nonnullable_rels,
3579 : pass_forced_null_vars);
3580 : }
3581 15456 : bms_free(local_nonnullable_rels);
3582 : }
3583 : }
3584 : else
3585 0 : elog(ERROR, "unrecognized node type: %d",
3586 : (int) nodeTag(jtnode));
3587 85332 : }
3588 :
3589 : /* Helper for reduce_outer_joins_pass2 */
3590 : static void
3591 50 : report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
3592 : int rtindex, Relids relids)
3593 : {
3594 : reduce_outer_joins_partial_state *statep;
3595 :
3596 50 : statep = palloc(sizeof(reduce_outer_joins_partial_state));
3597 50 : statep->full_join_rti = rtindex;
3598 50 : statep->unreduced_side = relids;
3599 50 : state2->partial_reduced = lappend(state2->partial_reduced, statep);
3600 50 : }
3601 :
3602 :
3603 : /*
3604 : * remove_useless_result_rtes
3605 : * Attempt to remove RTE_RESULT RTEs from the join tree.
3606 : * Also, elide single-child FromExprs where possible.
3607 : *
3608 : * We can remove RTE_RESULT entries from the join tree using the knowledge
3609 : * that RTE_RESULT returns exactly one row and has no output columns. Hence,
3610 : * if one is inner-joined to anything else, we can delete it. Optimizations
3611 : * are also possible for some outer-join cases, as detailed below.
3612 : *
3613 : * This pass also replaces single-child FromExprs with their child node
3614 : * where possible. It's appropriate to do that here and not earlier because
3615 : * RTE_RESULT removal might reduce a multiple-child FromExpr to have only one
3616 : * child. We can remove such a FromExpr if its quals are empty, or if it's
3617 : * semantically valid to merge the quals into those of the parent node.
3618 : * While removing unnecessary join tree nodes has some micro-efficiency value,
3619 : * the real reason to do this is to eliminate cases where the nullable side of
3620 : * an outer join node is a FromExpr whose single child is another outer join.
3621 : * To correctly determine whether the two outer joins can commute,
3622 : * deconstruct_jointree() must treat any quals of such a FromExpr as being
3623 : * degenerate quals of the upper outer join. The best way to do that is to
3624 : * make them actually *be* quals of the upper join, by dropping the FromExpr
3625 : * and hoisting the quals up into the upper join's quals. (Note that there is
3626 : * no hazard when the intermediate FromExpr has multiple children, since then
3627 : * it represents an inner join that cannot commute with the upper outer join.)
3628 : * As long as we have to do that, we might as well elide such FromExprs
3629 : * everywhere.
3630 : *
3631 : * Some of these optimizations depend on recognizing empty (constant-true)
3632 : * quals for FromExprs and JoinExprs. That makes it useful to apply this
3633 : * optimization pass after expression preprocessing, since that will have
3634 : * eliminated constant-true quals, allowing more cases to be recognized as
3635 : * optimizable. What's more, the usual reason for an RTE_RESULT to be present
3636 : * is that we pulled up a subquery or VALUES clause, thus very possibly
3637 : * replacing Vars with constants, making it more likely that a qual can be
3638 : * reduced to constant true. Also, because some optimizations depend on
3639 : * the outer-join type, it's best to have done reduce_outer_joins() first.
3640 : *
3641 : * A PlaceHolderVar referencing an RTE_RESULT RTE poses an obstacle to this
3642 : * process: we must remove the RTE_RESULT's relid from the PHV's phrels, but
3643 : * we must not reduce the phrels set to empty. If that would happen, and
3644 : * the RTE_RESULT is an immediate child of an outer join, we have to give up
3645 : * and not remove the RTE_RESULT: there is noplace else to evaluate the
3646 : * PlaceHolderVar. (That is, in such cases the RTE_RESULT *does* have output
3647 : * columns.) But if the RTE_RESULT is an immediate child of an inner join,
3648 : * we can usually change the PlaceHolderVar's phrels so as to evaluate it at
3649 : * the inner join instead. This is OK because we really only care that PHVs
3650 : * are evaluated above or below the correct outer joins. We can't, however,
3651 : * postpone the evaluation of a PHV to above where it is used; so there are
3652 : * some checks below on whether output PHVs are laterally referenced in the
3653 : * other join input rel(s).
3654 : *
3655 : * We used to try to do this work as part of pull_up_subqueries() where the
3656 : * potentially-optimizable cases get introduced; but it's way simpler, and
3657 : * more effective, to do it separately.
3658 : */
3659 : void
3660 232484 : remove_useless_result_rtes(PlannerInfo *root)
3661 : {
3662 232484 : Relids dropped_outer_joins = NULL;
3663 : ListCell *cell;
3664 :
3665 : /* Top level of jointree must always be a FromExpr */
3666 : Assert(IsA(root->parse->jointree, FromExpr));
3667 : /* Recurse ... */
3668 464968 : root->parse->jointree = (FromExpr *)
3669 232484 : remove_useless_results_recurse(root,
3670 232484 : (Node *) root->parse->jointree,
3671 : NULL,
3672 : &dropped_outer_joins);
3673 : /* We should still have a FromExpr */
3674 : Assert(IsA(root->parse->jointree, FromExpr));
3675 :
3676 : /*
3677 : * If we removed any outer-join nodes from the jointree, run around and
3678 : * remove references to those joins as nulling rels. (There could be such
3679 : * references in PHVs that we pulled up out of the original subquery that
3680 : * the RESULT rel replaced. This is kosher on the grounds that we now
3681 : * know that such an outer join wouldn't really have nulled anything.) We
3682 : * don't do this during the main recursion, for simplicity and because we
3683 : * can handle all such joins in a single pass over the parse tree.
3684 : */
3685 232484 : if (!bms_is_empty(dropped_outer_joins))
3686 : {
3687 60 : root->parse = (Query *)
3688 60 : remove_nulling_relids((Node *) root->parse,
3689 : dropped_outer_joins,
3690 : NULL);
3691 : /* There could be references in the append_rel_list, too */
3692 60 : root->append_rel_list = (List *)
3693 60 : remove_nulling_relids((Node *) root->append_rel_list,
3694 : dropped_outer_joins,
3695 : NULL);
3696 : }
3697 :
3698 : /*
3699 : * Remove any PlanRowMark referencing an RTE_RESULT RTE. We obviously
3700 : * must do that for any RTE_RESULT that we just removed. But one for a
3701 : * RTE that we did not remove can be dropped anyway: since the RTE has
3702 : * only one possible output row, there is no need for EPQ to mark and
3703 : * restore that row.
3704 : *
3705 : * It's necessary, not optional, to remove the PlanRowMark for a surviving
3706 : * RTE_RESULT RTE; otherwise we'll generate a whole-row Var for the
3707 : * RTE_RESULT, which the executor has no support for.
3708 : */
3709 234462 : foreach(cell, root->rowMarks)
3710 : {
3711 1978 : PlanRowMark *rc = (PlanRowMark *) lfirst(cell);
3712 :
3713 1978 : if (rt_fetch(rc->rti, root->parse->rtable)->rtekind == RTE_RESULT)
3714 840 : root->rowMarks = foreach_delete_current(root->rowMarks, cell);
3715 : }
3716 232484 : }
3717 :
3718 : /*
3719 : * remove_useless_results_recurse
3720 : * Recursive guts of remove_useless_result_rtes.
3721 : *
3722 : * This recursively processes the jointree and returns a modified jointree.
3723 : * In addition, the RT indexes of any removed outer-join nodes are added to
3724 : * *dropped_outer_joins.
3725 : *
3726 : * jtnode is the current jointree node. If it could be valid to merge
3727 : * its quals into those of the parent node, parent_quals should point to
3728 : * the parent's quals list; otherwise, pass NULL for parent_quals.
3729 : * (Note that in some cases, parent_quals points to the quals of a parent
3730 : * more than one level up in the tree.)
3731 : */
3732 : static Node *
3733 602852 : remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
3734 : Node **parent_quals,
3735 : Relids *dropped_outer_joins)
3736 : {
3737 : Assert(jtnode != NULL);
3738 602852 : if (IsA(jtnode, RangeTblRef))
3739 : {
3740 : /* Can't immediately do anything with a RangeTblRef */
3741 : }
3742 303104 : else if (IsA(jtnode, FromExpr))
3743 : {
3744 239312 : FromExpr *f = (FromExpr *) jtnode;
3745 239312 : Relids result_relids = NULL;
3746 : ListCell *cell;
3747 :
3748 : /*
3749 : * We can drop RTE_RESULT rels from the fromlist so long as at least
3750 : * one child remains, since joining to a one-row table changes
3751 : * nothing. (But we can't drop a RTE_RESULT that computes PHV(s) that
3752 : * are needed by some sibling. The cleanup transformation below would
3753 : * reassign the PHVs to be computed at the join, which is too late for
3754 : * the sibling's use.) The easiest way to mechanize this rule is to
3755 : * modify the list in-place.
3756 : */
3757 482096 : foreach(cell, f->fromlist)
3758 : {
3759 242784 : Node *child = (Node *) lfirst(cell);
3760 : int varno;
3761 :
3762 : /* Recursively transform child, allowing it to push up quals ... */
3763 242784 : child = remove_useless_results_recurse(root, child,
3764 : &f->quals,
3765 : dropped_outer_joins);
3766 : /* ... and stick it back into the tree */
3767 242784 : lfirst(cell) = child;
3768 :
3769 : /*
3770 : * If it's an RTE_RESULT with at least one sibling, and no sibling
3771 : * references dependent PHVs, we can drop it. We don't yet know
3772 : * what the inner join's final relid set will be, so postpone
3773 : * cleanup of PHVs etc till after this loop.
3774 : */
3775 248386 : if (list_length(f->fromlist) > 1 &&
3776 5602 : (varno = get_result_relid(root, child)) != 0 &&
3777 346 : !find_dependent_phvs_in_jointree(root, (Node *) f, varno))
3778 : {
3779 322 : f->fromlist = foreach_delete_current(f->fromlist, cell);
3780 322 : result_relids = bms_add_member(result_relids, varno);
3781 : }
3782 : }
3783 :
3784 : /*
3785 : * Clean up if we dropped any RTE_RESULT RTEs. This is a bit
3786 : * inefficient if there's more than one, but it seems better to
3787 : * optimize the support code for the single-relid case.
3788 : */
3789 239312 : if (result_relids)
3790 : {
3791 310 : int varno = -1;
3792 :
3793 632 : while ((varno = bms_next_member(result_relids, varno)) >= 0)
3794 322 : remove_result_refs(root, varno, (Node *) f);
3795 : }
3796 :
3797 : /*
3798 : * If the FromExpr now has only one child, see if we can elide it.
3799 : * This is always valid if there are no quals, except at the top of
3800 : * the jointree (since Query.jointree is required to point to a
3801 : * FromExpr). Otherwise, we can do it if we can push the quals up to
3802 : * the parent node.
3803 : *
3804 : * Note: while it would not be terribly hard to generalize this
3805 : * transformation to merge multi-child FromExprs into their parent
3806 : * FromExpr, that risks making the parent join too expensive to plan.
3807 : * We leave it to later processing to decide heuristically whether
3808 : * that's a good idea. Pulling up a single child is always OK,
3809 : * however.
3810 : */
3811 239312 : if (list_length(f->fromlist) == 1 &&
3812 237390 : f != root->parse->jointree &&
3813 6596 : (f->quals == NULL || parent_quals != NULL))
3814 : {
3815 : /*
3816 : * Merge any quals up to parent. They should be in implicit-AND
3817 : * format by now, so we just need to concatenate lists. Put the
3818 : * child quals at the front, on the grounds that they should
3819 : * nominally be evaluated earlier.
3820 : */
3821 2762 : if (f->quals != NULL)
3822 1390 : *parent_quals = (Node *)
3823 1390 : list_concat(castNode(List, f->quals),
3824 : castNode(List, *parent_quals));
3825 2762 : return (Node *) linitial(f->fromlist);
3826 : }
3827 : }
3828 63792 : else if (IsA(jtnode, JoinExpr))
3829 : {
3830 63792 : JoinExpr *j = (JoinExpr *) jtnode;
3831 : int varno;
3832 :
3833 : /*
3834 : * First, recurse. We can absorb pushed-up FromExpr quals from either
3835 : * child into this node if the jointype is INNER, since then this is
3836 : * equivalent to a FromExpr. When the jointype is LEFT, we can absorb
3837 : * quals from the RHS child into the current node, as they're
3838 : * essentially degenerate quals of the outer join. Moreover, if we've
3839 : * been passed down a parent_quals pointer then we can allow quals of
3840 : * the LHS child to be absorbed into the parent. (This is important
3841 : * to ensure we remove single-child FromExprs immediately below
3842 : * commutable left joins.) For other jointypes, we can't move child
3843 : * quals up, or at least there's no particular reason to.
3844 : */
3845 63792 : j->larg = remove_useless_results_recurse(root, j->larg,
3846 63792 : (j->jointype == JOIN_INNER) ?
3847 : &j->quals :
3848 50274 : (j->jointype == JOIN_LEFT) ?
3849 50274 : parent_quals : NULL,
3850 : dropped_outer_joins);
3851 63792 : j->rarg = remove_useless_results_recurse(root, j->rarg,
3852 63792 : (j->jointype == JOIN_INNER ||
3853 50274 : j->jointype == JOIN_LEFT) ?
3854 : &j->quals : NULL,
3855 : dropped_outer_joins);
3856 :
3857 : /* Apply join-type-specific optimization rules */
3858 63792 : switch (j->jointype)
3859 : {
3860 13518 : case JOIN_INNER:
3861 :
3862 : /*
3863 : * An inner join is equivalent to a FromExpr, so if either
3864 : * side was simplified to an RTE_RESULT rel, we can replace
3865 : * the join with a FromExpr with just the other side.
3866 : * Furthermore, we can elide that FromExpr according to the
3867 : * same rules as above.
3868 : *
3869 : * Just as in the FromExpr case, we can't simplify if the
3870 : * other input rel references any PHVs that are marked as to
3871 : * be evaluated at the RTE_RESULT rel, because we can't
3872 : * postpone their evaluation in that case. But we only have
3873 : * to check this in cases where it's syntactically legal for
3874 : * the other input to have a LATERAL reference to the
3875 : * RTE_RESULT rel. Only RHSes of inner and left joins are
3876 : * allowed to have such refs.
3877 : */
3878 13518 : if ((varno = get_result_relid(root, j->larg)) != 0 &&
3879 106 : !find_dependent_phvs_in_jointree(root, j->rarg, varno))
3880 : {
3881 106 : remove_result_refs(root, varno, j->rarg);
3882 106 : if (j->quals != NULL && parent_quals == NULL)
3883 12 : jtnode = (Node *)
3884 12 : makeFromExpr(list_make1(j->rarg), j->quals);
3885 : else
3886 : {
3887 : /* Merge any quals up to parent */
3888 94 : if (j->quals != NULL)
3889 70 : *parent_quals = (Node *)
3890 70 : list_concat(castNode(List, j->quals),
3891 : castNode(List, *parent_quals));
3892 94 : jtnode = j->rarg;
3893 : }
3894 : }
3895 13412 : else if ((varno = get_result_relid(root, j->rarg)) != 0)
3896 : {
3897 788 : remove_result_refs(root, varno, j->larg);
3898 788 : if (j->quals != NULL && parent_quals == NULL)
3899 12 : jtnode = (Node *)
3900 12 : makeFromExpr(list_make1(j->larg), j->quals);
3901 : else
3902 : {
3903 : /* Merge any quals up to parent */
3904 776 : if (j->quals != NULL)
3905 512 : *parent_quals = (Node *)
3906 512 : list_concat(castNode(List, j->quals),
3907 : castNode(List, *parent_quals));
3908 776 : jtnode = j->larg;
3909 : }
3910 : }
3911 13518 : break;
3912 44464 : case JOIN_LEFT:
3913 :
3914 : /*
3915 : * We can simplify this case if the RHS is an RTE_RESULT, with
3916 : * two different possibilities:
3917 : *
3918 : * If the qual is empty (JOIN ON TRUE), then the join can be
3919 : * strength-reduced to a plain inner join, since each LHS row
3920 : * necessarily has exactly one join partner. So we can always
3921 : * discard the RHS, much as in the JOIN_INNER case above.
3922 : * (Again, the LHS could not contain a lateral reference to
3923 : * the RHS.)
3924 : *
3925 : * Otherwise, it's still true that each LHS row should be
3926 : * returned exactly once, and since the RHS returns no columns
3927 : * (unless there are PHVs that have to be evaluated there), we
3928 : * don't much care if it's null-extended or not. So in this
3929 : * case also, we can just ignore the qual and discard the left
3930 : * join.
3931 : */
3932 44464 : if ((varno = get_result_relid(root, j->rarg)) != 0 &&
3933 150 : (j->quals == NULL ||
3934 90 : !find_dependent_phvs(root, varno)))
3935 : {
3936 60 : remove_result_refs(root, varno, j->larg);
3937 60 : *dropped_outer_joins = bms_add_member(*dropped_outer_joins,
3938 : j->rtindex);
3939 60 : jtnode = j->larg;
3940 : }
3941 44464 : break;
3942 3196 : case JOIN_SEMI:
3943 :
3944 : /*
3945 : * We may simplify this case if the RHS is an RTE_RESULT; the
3946 : * join qual becomes effectively just a filter qual for the
3947 : * LHS, since we should either return the LHS row or not. The
3948 : * filter clause must go into a new FromExpr if we can't push
3949 : * it up to the parent.
3950 : *
3951 : * There is a fine point about PHVs that are supposed to be
3952 : * evaluated at the RHS. Such PHVs could only appear in the
3953 : * semijoin's qual, since the rest of the query cannot
3954 : * reference any outputs of the semijoin's RHS. Therefore,
3955 : * they can't actually go to null before being examined, and
3956 : * it'd be OK to just remove the PHV wrapping. We don't have
3957 : * infrastructure for that, but remove_result_refs() will
3958 : * relabel them as to be evaluated at the LHS, which is fine.
3959 : *
3960 : * Also, we don't need to worry about removing traces of the
3961 : * join's rtindex, since it hasn't got one.
3962 : */
3963 3196 : if ((varno = get_result_relid(root, j->rarg)) != 0)
3964 : {
3965 : Assert(j->rtindex == 0);
3966 36 : remove_result_refs(root, varno, j->larg);
3967 36 : if (j->quals != NULL && parent_quals == NULL)
3968 0 : jtnode = (Node *)
3969 0 : makeFromExpr(list_make1(j->larg), j->quals);
3970 : else
3971 : {
3972 : /* Merge any quals up to parent */
3973 36 : if (j->quals != NULL)
3974 36 : *parent_quals = (Node *)
3975 36 : list_concat(castNode(List, j->quals),
3976 : castNode(List, *parent_quals));
3977 36 : jtnode = j->larg;
3978 : }
3979 : }
3980 3196 : break;
3981 2614 : case JOIN_FULL:
3982 : case JOIN_ANTI:
3983 : /* We have no special smarts for these cases */
3984 2614 : break;
3985 0 : default:
3986 : /* Note: JOIN_RIGHT should be gone at this point */
3987 0 : elog(ERROR, "unrecognized join type: %d",
3988 : (int) j->jointype);
3989 : break;
3990 : }
3991 : }
3992 : else
3993 0 : elog(ERROR, "unrecognized node type: %d",
3994 : (int) nodeTag(jtnode));
3995 600090 : return jtnode;
3996 : }
3997 :
3998 : /*
3999 : * get_result_relid
4000 : * If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
4001 : * otherwise return 0.
4002 : */
4003 : static int
4004 80192 : get_result_relid(PlannerInfo *root, Node *jtnode)
4005 : {
4006 : int varno;
4007 :
4008 80192 : if (!IsA(jtnode, RangeTblRef))
4009 6628 : return 0;
4010 73564 : varno = ((RangeTblRef *) jtnode)->rtindex;
4011 73564 : if (rt_fetch(varno, root->parse->rtable)->rtekind != RTE_RESULT)
4012 72138 : return 0;
4013 1426 : return varno;
4014 : }
4015 :
4016 : /*
4017 : * remove_result_refs
4018 : * Helper routine for dropping an unneeded RTE_RESULT RTE.
4019 : *
4020 : * This doesn't physically remove the RTE from the jointree, because that's
4021 : * more easily handled in remove_useless_results_recurse. What it does do
4022 : * is the necessary cleanup in the rest of the tree: we must adjust any PHVs
4023 : * that may reference the RTE. Be sure to call this at a point where the
4024 : * jointree is valid (no disconnected nodes).
4025 : *
4026 : * Note that we don't need to process the append_rel_list, since RTEs
4027 : * referenced directly in the jointree won't be appendrel members.
4028 : *
4029 : * varno is the RTE_RESULT's relid.
4030 : * newjtloc is the jointree location at which any PHVs referencing the
4031 : * RTE_RESULT should be evaluated instead.
4032 : */
4033 : static void
4034 1312 : remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc)
4035 : {
4036 : /* Fix up PlaceHolderVars as needed */
4037 : /* If there are no PHVs anywhere, we can skip this bit */
4038 1312 : if (root->glob->lastPHId != 0)
4039 : {
4040 : Relids subrelids;
4041 :
4042 272 : subrelids = get_relids_in_jointree(newjtloc, true, false);
4043 : Assert(!bms_is_empty(subrelids));
4044 272 : substitute_phv_relids((Node *) root->parse, varno, subrelids);
4045 272 : fix_append_rel_relids(root, varno, subrelids);
4046 : }
4047 :
4048 : /*
4049 : * We also need to remove any PlanRowMark referencing the RTE, but we
4050 : * postpone that work until we return to remove_useless_result_rtes.
4051 : */
4052 1312 : }
4053 :
4054 :
4055 : /*
4056 : * find_dependent_phvs - are there any PlaceHolderVars whose relids are
4057 : * exactly the given varno?
4058 : *
4059 : * find_dependent_phvs should be used when we want to see if there are
4060 : * any such PHVs anywhere in the Query. Another use-case is to see if
4061 : * a subtree of the join tree contains such PHVs; but for that, we have
4062 : * to look not only at the join tree nodes themselves but at the
4063 : * referenced RTEs. For that, use find_dependent_phvs_in_jointree.
4064 : */
4065 :
4066 : typedef struct
4067 : {
4068 : Relids relids;
4069 : int sublevels_up;
4070 : } find_dependent_phvs_context;
4071 :
4072 : static bool
4073 2400 : find_dependent_phvs_walker(Node *node,
4074 : find_dependent_phvs_context *context)
4075 : {
4076 2400 : if (node == NULL)
4077 564 : return false;
4078 1836 : if (IsA(node, PlaceHolderVar))
4079 : {
4080 156 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4081 :
4082 312 : if (phv->phlevelsup == context->sublevels_up &&
4083 156 : bms_equal(context->relids, phv->phrels))
4084 114 : return true;
4085 : /* fall through to examine children */
4086 : }
4087 1722 : if (IsA(node, Query))
4088 : {
4089 : /* Recurse into subselects */
4090 : bool result;
4091 :
4092 48 : context->sublevels_up++;
4093 48 : result = query_tree_walker((Query *) node,
4094 : find_dependent_phvs_walker,
4095 : context, 0);
4096 48 : context->sublevels_up--;
4097 48 : return result;
4098 : }
4099 : /* Shouldn't need to handle most planner auxiliary nodes here */
4100 : Assert(!IsA(node, SpecialJoinInfo));
4101 : Assert(!IsA(node, PlaceHolderInfo));
4102 : Assert(!IsA(node, MinMaxAggInfo));
4103 :
4104 1674 : return expression_tree_walker(node, find_dependent_phvs_walker, context);
4105 : }
4106 :
4107 : static bool
4108 90 : find_dependent_phvs(PlannerInfo *root, int varno)
4109 : {
4110 : find_dependent_phvs_context context;
4111 :
4112 : /* If there are no PHVs anywhere, we needn't work hard */
4113 90 : if (root->glob->lastPHId == 0)
4114 0 : return false;
4115 :
4116 90 : context.relids = bms_make_singleton(varno);
4117 90 : context.sublevels_up = 0;
4118 :
4119 90 : if (query_tree_walker(root->parse, find_dependent_phvs_walker, &context, 0))
4120 90 : return true;
4121 : /* The append_rel_list could be populated already, so check it too */
4122 0 : if (expression_tree_walker((Node *) root->append_rel_list,
4123 : find_dependent_phvs_walker,
4124 : &context))
4125 0 : return true;
4126 0 : return false;
4127 : }
4128 :
4129 : static bool
4130 452 : find_dependent_phvs_in_jointree(PlannerInfo *root, Node *node, int varno)
4131 : {
4132 : find_dependent_phvs_context context;
4133 : Relids subrelids;
4134 : int relid;
4135 :
4136 : /* If there are no PHVs anywhere, we needn't work hard */
4137 452 : if (root->glob->lastPHId == 0)
4138 386 : return false;
4139 :
4140 66 : context.relids = bms_make_singleton(varno);
4141 66 : context.sublevels_up = 0;
4142 :
4143 : /*
4144 : * See if the jointree fragment itself contains references (in join quals)
4145 : */
4146 66 : if (find_dependent_phvs_walker(node, &context))
4147 0 : return true;
4148 :
4149 : /*
4150 : * Otherwise, identify the set of referenced RTEs (we can ignore joins,
4151 : * since they should be flattened already, so their join alias lists no
4152 : * longer matter), and tediously check each RTE. We can ignore RTEs that
4153 : * are not marked LATERAL, though, since they couldn't possibly contain
4154 : * any cross-references to other RTEs.
4155 : */
4156 66 : subrelids = get_relids_in_jointree(node, false, false);
4157 66 : relid = -1;
4158 144 : while ((relid = bms_next_member(subrelids, relid)) >= 0)
4159 : {
4160 102 : RangeTblEntry *rte = rt_fetch(relid, root->parse->rtable);
4161 :
4162 126 : if (rte->lateral &&
4163 24 : range_table_entry_walker(rte, find_dependent_phvs_walker, &context, 0))
4164 24 : return true;
4165 : }
4166 :
4167 42 : return false;
4168 : }
4169 :
4170 : /*
4171 : * substitute_phv_relids - adjust PlaceHolderVar relid sets after pulling up
4172 : * a subquery or removing an RTE_RESULT jointree item
4173 : *
4174 : * Find any PlaceHolderVar nodes in the given tree that reference the
4175 : * pulled-up relid, and change them to reference the replacement relid(s).
4176 : *
4177 : * NOTE: although this has the form of a walker, we cheat and modify the
4178 : * nodes in-place. This should be OK since the tree was copied by
4179 : * pullup_replace_vars earlier. Avoid scribbling on the original values of
4180 : * the bitmapsets, though, because expression_tree_mutator doesn't copy those.
4181 : */
4182 :
4183 : typedef struct
4184 : {
4185 : int varno;
4186 : int sublevels_up;
4187 : Relids subrelids;
4188 : } substitute_phv_relids_context;
4189 :
4190 : static bool
4191 269462 : substitute_phv_relids_walker(Node *node,
4192 : substitute_phv_relids_context *context)
4193 : {
4194 269462 : if (node == NULL)
4195 102626 : return false;
4196 166836 : if (IsA(node, PlaceHolderVar))
4197 : {
4198 7660 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4199 :
4200 15288 : if (phv->phlevelsup == context->sublevels_up &&
4201 7628 : bms_is_member(context->varno, phv->phrels))
4202 : {
4203 10936 : phv->phrels = bms_union(phv->phrels,
4204 5468 : context->subrelids);
4205 5468 : phv->phrels = bms_del_member(phv->phrels,
4206 : context->varno);
4207 : /* Assert we haven't broken the PHV */
4208 : Assert(!bms_is_empty(phv->phrels));
4209 : }
4210 : /* fall through to examine children */
4211 : }
4212 166836 : if (IsA(node, Query))
4213 : {
4214 : /* Recurse into subselects */
4215 : bool result;
4216 :
4217 4428 : context->sublevels_up++;
4218 4428 : result = query_tree_walker((Query *) node,
4219 : substitute_phv_relids_walker,
4220 : context, 0);
4221 4428 : context->sublevels_up--;
4222 4428 : return result;
4223 : }
4224 : /* Shouldn't need to handle planner auxiliary nodes here */
4225 : Assert(!IsA(node, SpecialJoinInfo));
4226 : Assert(!IsA(node, AppendRelInfo));
4227 : Assert(!IsA(node, PlaceHolderInfo));
4228 : Assert(!IsA(node, MinMaxAggInfo));
4229 :
4230 162408 : return expression_tree_walker(node, substitute_phv_relids_walker, context);
4231 : }
4232 :
4233 : static void
4234 2424 : substitute_phv_relids(Node *node, int varno, Relids subrelids)
4235 : {
4236 : substitute_phv_relids_context context;
4237 :
4238 2424 : context.varno = varno;
4239 2424 : context.sublevels_up = 0;
4240 2424 : context.subrelids = subrelids;
4241 :
4242 : /*
4243 : * Must be prepared to start with a Query or a bare expression tree.
4244 : */
4245 2424 : query_or_expression_tree_walker(node,
4246 : substitute_phv_relids_walker,
4247 : &context,
4248 : 0);
4249 2424 : }
4250 :
4251 : /*
4252 : * fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
4253 : *
4254 : * When we pull up a subquery, any AppendRelInfo references to the subquery's
4255 : * RT index have to be replaced by the substituted relid (and there had better
4256 : * be only one). We also need to apply substitute_phv_relids to their
4257 : * translated_vars lists, since those might contain PlaceHolderVars.
4258 : *
4259 : * We assume we may modify the AppendRelInfo nodes in-place.
4260 : */
4261 : static void
4262 8438 : fix_append_rel_relids(PlannerInfo *root, int varno, Relids subrelids)
4263 : {
4264 : ListCell *l;
4265 8438 : int subvarno = -1;
4266 :
4267 : /*
4268 : * We only want to extract the member relid once, but we mustn't fail
4269 : * immediately if there are multiple members; it could be that none of the
4270 : * AppendRelInfo nodes refer to it. So compute it on first use. Note that
4271 : * bms_singleton_member will complain if set is not singleton.
4272 : */
4273 19962 : foreach(l, root->append_rel_list)
4274 : {
4275 11524 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
4276 :
4277 : /* The parent_relid shouldn't ever be a pullup target */
4278 : Assert(appinfo->parent_relid != varno);
4279 :
4280 11524 : if (appinfo->child_relid == varno)
4281 : {
4282 6230 : if (subvarno < 0)
4283 6230 : subvarno = bms_singleton_member(subrelids);
4284 6230 : appinfo->child_relid = subvarno;
4285 : }
4286 :
4287 : /* Also fix up any PHVs in its translated vars */
4288 11524 : if (root->glob->lastPHId != 0)
4289 162 : substitute_phv_relids((Node *) appinfo->translated_vars,
4290 : varno, subrelids);
4291 : }
4292 8438 : }
4293 :
4294 : /*
4295 : * get_relids_in_jointree: get set of RT indexes present in a jointree
4296 : *
4297 : * Base-relation relids are always included in the result.
4298 : * If include_outer_joins is true, outer-join RT indexes are included.
4299 : * If include_inner_joins is true, inner-join RT indexes are included.
4300 : *
4301 : * Note that for most purposes in the planner, outer joins are included
4302 : * in standard relid sets. Setting include_inner_joins true is only
4303 : * appropriate for special purposes during subquery flattening.
4304 : */
4305 : Relids
4306 93770 : get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
4307 : bool include_inner_joins)
4308 : {
4309 93770 : Relids result = NULL;
4310 :
4311 93770 : if (jtnode == NULL)
4312 0 : return result;
4313 93770 : if (IsA(jtnode, RangeTblRef))
4314 : {
4315 47282 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4316 :
4317 47282 : result = bms_make_singleton(varno);
4318 : }
4319 46488 : else if (IsA(jtnode, FromExpr))
4320 : {
4321 40170 : FromExpr *f = (FromExpr *) jtnode;
4322 : ListCell *l;
4323 :
4324 81612 : foreach(l, f->fromlist)
4325 : {
4326 41442 : result = bms_join(result,
4327 41442 : get_relids_in_jointree(lfirst(l),
4328 : include_outer_joins,
4329 : include_inner_joins));
4330 : }
4331 : }
4332 6318 : else if (IsA(jtnode, JoinExpr))
4333 : {
4334 6318 : JoinExpr *j = (JoinExpr *) jtnode;
4335 :
4336 6318 : result = get_relids_in_jointree(j->larg,
4337 : include_outer_joins,
4338 : include_inner_joins);
4339 6318 : result = bms_join(result,
4340 : get_relids_in_jointree(j->rarg,
4341 : include_outer_joins,
4342 : include_inner_joins));
4343 6318 : if (j->rtindex)
4344 : {
4345 5992 : if (j->jointype == JOIN_INNER)
4346 : {
4347 2670 : if (include_inner_joins)
4348 1042 : result = bms_add_member(result, j->rtindex);
4349 : }
4350 : else
4351 : {
4352 3322 : if (include_outer_joins)
4353 2158 : result = bms_add_member(result, j->rtindex);
4354 : }
4355 : }
4356 : }
4357 : else
4358 0 : elog(ERROR, "unrecognized node type: %d",
4359 : (int) nodeTag(jtnode));
4360 93770 : return result;
4361 : }
4362 :
4363 : /*
4364 : * get_relids_for_join: get set of base+OJ RT indexes making up a join
4365 : */
4366 : Relids
4367 358 : get_relids_for_join(Query *query, int joinrelid)
4368 : {
4369 : Node *jtnode;
4370 :
4371 358 : jtnode = find_jointree_node_for_rel((Node *) query->jointree,
4372 : joinrelid);
4373 358 : if (!jtnode)
4374 0 : elog(ERROR, "could not find join node %d", joinrelid);
4375 358 : return get_relids_in_jointree(jtnode, true, false);
4376 : }
4377 :
4378 : /*
4379 : * find_jointree_node_for_rel: locate jointree node for a base or join RT index
4380 : *
4381 : * Returns NULL if not found
4382 : */
4383 : static Node *
4384 1730 : find_jointree_node_for_rel(Node *jtnode, int relid)
4385 : {
4386 1730 : if (jtnode == NULL)
4387 0 : return NULL;
4388 1730 : if (IsA(jtnode, RangeTblRef))
4389 : {
4390 454 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4391 :
4392 454 : if (relid == varno)
4393 0 : return jtnode;
4394 : }
4395 1276 : else if (IsA(jtnode, FromExpr))
4396 : {
4397 368 : FromExpr *f = (FromExpr *) jtnode;
4398 : ListCell *l;
4399 :
4400 386 : foreach(l, f->fromlist)
4401 : {
4402 386 : jtnode = find_jointree_node_for_rel(lfirst(l), relid);
4403 386 : if (jtnode)
4404 368 : return jtnode;
4405 : }
4406 : }
4407 908 : else if (IsA(jtnode, JoinExpr))
4408 : {
4409 908 : JoinExpr *j = (JoinExpr *) jtnode;
4410 :
4411 908 : if (relid == j->rtindex)
4412 358 : return jtnode;
4413 550 : jtnode = find_jointree_node_for_rel(j->larg, relid);
4414 550 : if (jtnode)
4415 114 : return jtnode;
4416 436 : jtnode = find_jointree_node_for_rel(j->rarg, relid);
4417 436 : if (jtnode)
4418 436 : return jtnode;
4419 : }
4420 : else
4421 0 : elog(ERROR, "unrecognized node type: %d",
4422 : (int) nodeTag(jtnode));
4423 454 : return NULL;
4424 : }
4425 :
4426 : /*
4427 : * get_nullingrels: collect info about which outer joins null which relations
4428 : *
4429 : * The result struct contains, for each leaf relation used in the query,
4430 : * the set of relids of outer joins that potentially null that rel.
4431 : */
4432 : static nullingrel_info *
4433 1158 : get_nullingrels(Query *parse)
4434 : {
4435 1158 : nullingrel_info *result = palloc_object(nullingrel_info);
4436 :
4437 1158 : result->rtlength = list_length(parse->rtable);
4438 1158 : result->nullingrels = palloc0_array(Relids, result->rtlength + 1);
4439 1158 : get_nullingrels_recurse((Node *) parse->jointree, NULL, result);
4440 1158 : return result;
4441 : }
4442 :
4443 : /*
4444 : * Recursive guts of get_nullingrels().
4445 : *
4446 : * Note: at any recursion level, the passed-down upper_nullingrels must be
4447 : * treated as a constant, but it can be stored directly into *info
4448 : * if we're at leaf level. Upper recursion levels do not free their mutated
4449 : * copies of the nullingrels, because those are probably referenced by
4450 : * at least one leaf rel.
4451 : */
4452 : static void
4453 6120 : get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
4454 : nullingrel_info *info)
4455 : {
4456 6120 : if (jtnode == NULL)
4457 0 : return;
4458 6120 : if (IsA(jtnode, RangeTblRef))
4459 : {
4460 3238 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4461 :
4462 : Assert(varno > 0 && varno <= info->rtlength);
4463 3238 : info->nullingrels[varno] = upper_nullingrels;
4464 : }
4465 2882 : else if (IsA(jtnode, FromExpr))
4466 : {
4467 1242 : FromExpr *f = (FromExpr *) jtnode;
4468 : ListCell *l;
4469 :
4470 2924 : foreach(l, f->fromlist)
4471 : {
4472 1682 : get_nullingrels_recurse(lfirst(l), upper_nullingrels, info);
4473 : }
4474 : }
4475 1640 : else if (IsA(jtnode, JoinExpr))
4476 : {
4477 1640 : JoinExpr *j = (JoinExpr *) jtnode;
4478 : Relids local_nullingrels;
4479 :
4480 1640 : switch (j->jointype)
4481 : {
4482 590 : case JOIN_INNER:
4483 590 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4484 590 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4485 590 : break;
4486 1044 : case JOIN_LEFT:
4487 : case JOIN_SEMI:
4488 : case JOIN_ANTI:
4489 1044 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4490 : j->rtindex);
4491 1044 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4492 1044 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4493 1044 : break;
4494 6 : case JOIN_FULL:
4495 6 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4496 : j->rtindex);
4497 6 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4498 6 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4499 6 : break;
4500 0 : case JOIN_RIGHT:
4501 0 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4502 : j->rtindex);
4503 0 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4504 0 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4505 0 : break;
4506 0 : default:
4507 0 : elog(ERROR, "unrecognized join type: %d",
4508 : (int) j->jointype);
4509 : break;
4510 : }
4511 : }
4512 : else
4513 0 : elog(ERROR, "unrecognized node type: %d",
4514 : (int) nodeTag(jtnode));
4515 : }
|
