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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * prepunion.c
4 : : * Routines to plan set-operation queries. The filename is a leftover
5 : : * from a time when only UNIONs were implemented.
6 : : *
7 : : * There are two code paths in the planner for set-operation queries.
8 : : * If a subquery consists entirely of simple UNION ALL operations, it
9 : : * is converted into an "append relation". Otherwise, it is handled
10 : : * by the general code in this module (plan_set_operations and its
11 : : * subroutines). There is some support code here for the append-relation
12 : : * case, but most of the heavy lifting for that is done elsewhere,
13 : : * notably in prepjointree.c and allpaths.c.
14 : : *
15 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
16 : : * Portions Copyright (c) 1994, Regents of the University of California
17 : : *
18 : : *
19 : : * IDENTIFICATION
20 : : * src/backend/optimizer/prep/prepunion.c
21 : : *
22 : : *-------------------------------------------------------------------------
23 : : */
24 : : #include "postgres.h"
25 : :
26 : : #include <math.h>
27 : :
28 : : #include "access/htup_details.h"
29 : : #include "catalog/pg_type.h"
30 : : #include "miscadmin.h"
31 : : #include "nodes/makefuncs.h"
32 : : #include "nodes/nodeFuncs.h"
33 : : #include "optimizer/cost.h"
34 : : #include "optimizer/pathnode.h"
35 : : #include "optimizer/paths.h"
36 : : #include "optimizer/planner.h"
37 : : #include "optimizer/prep.h"
38 : : #include "optimizer/tlist.h"
39 : : #include "parser/parse_coerce.h"
40 : : #include "port/pg_bitutils.h"
41 : : #include "utils/selfuncs.h"
42 : :
43 : :
44 : : static RelOptInfo *recurse_set_operations(Node *setOp, PlannerInfo *root,
45 : : SetOperationStmt *parentOp,
46 : : List *colTypes, List *colCollations,
47 : : List *refnames_tlist,
48 : : List **pTargetList,
49 : : bool *istrivial_tlist);
50 : : static RelOptInfo *generate_recursion_path(SetOperationStmt *setOp,
51 : : PlannerInfo *root,
52 : : List *refnames_tlist,
53 : : List **pTargetList);
54 : : static void build_setop_child_paths(PlannerInfo *root, RelOptInfo *rel,
55 : : bool trivial_tlist, List *child_tlist,
56 : : List *interesting_pathkeys,
57 : : double *pNumGroups);
58 : : static RelOptInfo *generate_union_paths(SetOperationStmt *op, PlannerInfo *root,
59 : : List *refnames_tlist,
60 : : List **pTargetList);
61 : : static RelOptInfo *generate_nonunion_paths(SetOperationStmt *op, PlannerInfo *root,
62 : : List *refnames_tlist,
63 : : List **pTargetList);
64 : : static List *plan_union_children(PlannerInfo *root,
65 : : SetOperationStmt *top_union,
66 : : List *refnames_tlist,
67 : : List **tlist_list,
68 : : List **istrivial_tlist);
69 : : static void postprocess_setop_rel(PlannerInfo *root, RelOptInfo *rel);
70 : : static List *generate_setop_tlist(List *colTypes, List *colCollations,
71 : : Index varno,
72 : : bool hack_constants,
73 : : List *input_tlist,
74 : : List *refnames_tlist,
75 : : bool *trivial_tlist);
76 : : static List *generate_append_tlist(List *colTypes, List *colCollations,
77 : : List *input_tlists,
78 : : List *refnames_tlist);
79 : : static List *generate_setop_grouplist(SetOperationStmt *op, List *targetlist);
80 : : static PathTarget *create_setop_pathtarget(PlannerInfo *root, List *tlist,
81 : : List *child_pathlist);
82 : :
83 : :
84 : : /*
85 : : * plan_set_operations
86 : : *
87 : : * Plans the queries for a tree of set operations (UNION/INTERSECT/EXCEPT)
88 : : *
89 : : * This routine only deals with the setOperations tree of the given query.
90 : : * Any top-level ORDER BY requested in root->parse->sortClause will be handled
91 : : * when we return to grouping_planner; likewise for LIMIT.
92 : : *
93 : : * What we return is an "upperrel" RelOptInfo containing at least one Path
94 : : * that implements the set-operation tree. In addition, root->processed_tlist
95 : : * receives a targetlist representing the output of the topmost setop node.
96 : : */
97 : : RelOptInfo *
98 : 4835 : plan_set_operations(PlannerInfo *root)
99 : : {
100 : 4835 : Query *parse = root->parse;
101 : 4835 : SetOperationStmt *topop = castNode(SetOperationStmt, parse->setOperations);
102 : : Node *node;
103 : : RangeTblEntry *leftmostRTE;
104 : : Query *leftmostQuery;
105 : : RelOptInfo *setop_rel;
106 : : List *top_tlist;
107 : :
108 : : Assert(topop);
109 : :
110 : : /* check for unsupported stuff */
111 : : Assert(parse->jointree->fromlist == NIL);
112 : : Assert(parse->jointree->quals == NULL);
113 : : Assert(parse->groupClause == NIL);
114 : : Assert(parse->havingQual == NULL);
115 : : Assert(parse->windowClause == NIL);
116 : : Assert(parse->distinctClause == NIL);
117 : :
118 : : /*
119 : : * In the outer query level, equivalence classes are limited to classes
120 : : * which define that the top-level target entry is equivalent to the
121 : : * corresponding child target entry. There won't be any equivalence class
122 : : * merging. Mark that merging is complete to allow us to make pathkeys.
123 : : */
124 : : Assert(root->eq_classes == NIL);
125 : 4835 : root->ec_merging_done = true;
126 : :
127 : : /*
128 : : * We'll need to build RelOptInfos for each of the leaf subqueries, which
129 : : * are RTE_SUBQUERY rangetable entries in this Query. Prepare the index
130 : : * arrays for those, and for AppendRelInfos in case they're needed.
131 : : */
132 : 4835 : setup_simple_rel_arrays(root);
133 : :
134 : : /*
135 : : * Find the leftmost component Query. We need to use its column names for
136 : : * all generated tlists (else SELECT INTO won't work right).
137 : : */
138 : 4835 : node = topop->larg;
139 [ + - + + ]: 8062 : while (node && IsA(node, SetOperationStmt))
140 : 3227 : node = ((SetOperationStmt *) node)->larg;
141 : : Assert(node && IsA(node, RangeTblRef));
142 : 4835 : leftmostRTE = root->simple_rte_array[((RangeTblRef *) node)->rtindex];
143 : 4835 : leftmostQuery = leftmostRTE->subquery;
144 : : Assert(leftmostQuery != NULL);
145 : :
146 : : /*
147 : : * If the topmost node is a recursive union, it needs special processing.
148 : : */
149 [ + + ]: 4835 : if (root->hasRecursion)
150 : : {
151 : 637 : setop_rel = generate_recursion_path(topop, root,
152 : : leftmostQuery->targetList,
153 : : &top_tlist);
154 : : }
155 : : else
156 : : {
157 : : bool trivial_tlist;
158 : :
159 : : /*
160 : : * Recurse on setOperations tree to generate paths for set ops. The
161 : : * final output paths should have just the column types shown as the
162 : : * output from the top-level node.
163 : : */
164 : 4198 : setop_rel = recurse_set_operations((Node *) topop, root,
165 : : NULL, /* no parent */
166 : : topop->colTypes, topop->colCollations,
167 : : leftmostQuery->targetList,
168 : : &top_tlist,
169 : : &trivial_tlist);
170 : : }
171 : :
172 : : /* Must return the built tlist into root->processed_tlist. */
173 : 4831 : root->processed_tlist = top_tlist;
174 : :
175 : 4831 : return setop_rel;
176 : : }
177 : :
178 : : /*
179 : : * recurse_set_operations
180 : : * Recursively handle one step in a tree of set operations
181 : : *
182 : : * setOp: current step (could be a SetOperationStmt or a leaf RangeTblRef)
183 : : * parentOp: parent step, or NULL if none (but see below)
184 : : * colTypes: OID list of set-op's result column datatypes
185 : : * colCollations: OID list of set-op's result column collations
186 : : * refnames_tlist: targetlist to take column names from
187 : : *
188 : : * parentOp should be passed as NULL unless that step is interested in
189 : : * getting sorted output from this step. ("Sorted" means "sorted according
190 : : * to the default btree opclasses of the result column datatypes".)
191 : : *
192 : : * Returns a RelOptInfo for the subtree, as well as these output parameters:
193 : : * *pTargetList: receives the fully-fledged tlist for the subtree's top plan
194 : : * *istrivial_tlist: true if, and only if, datatypes between parent and child
195 : : * match.
196 : : *
197 : : * If setOp is a leaf node, this function plans the sub-query but does
198 : : * not populate the pathlist of the returned RelOptInfo. The caller will
199 : : * generate SubqueryScan paths using useful path(s) of the subquery (see
200 : : * build_setop_child_paths). But this function does build the paths for
201 : : * set-operation nodes.
202 : : *
203 : : * The pTargetList output parameter is mostly redundant with the pathtarget
204 : : * of the returned RelOptInfo, but for the moment we need it because much of
205 : : * the logic in this file depends on flag columns being marked resjunk.
206 : : * XXX Now that there are no flag columns and hence no resjunk columns, we
207 : : * could probably refactor this file to deal only in pathtargets.
208 : : *
209 : : * We don't have to care about typmods here: the only allowed difference
210 : : * between set-op input and output typmods is input is a specific typmod
211 : : * and output is -1, and that does not require a coercion.
212 : : */
213 : : static RelOptInfo *
214 : 17300 : recurse_set_operations(Node *setOp, PlannerInfo *root,
215 : : SetOperationStmt *parentOp,
216 : : List *colTypes, List *colCollations,
217 : : List *refnames_tlist,
218 : : List **pTargetList,
219 : : bool *istrivial_tlist)
220 : : {
221 : : RelOptInfo *rel;
222 : :
223 : 17300 : *istrivial_tlist = true; /* for now */
224 : :
225 : : /* Guard against stack overflow due to overly complex setop nests */
226 : 17300 : check_stack_depth();
227 : :
228 [ + + ]: 17300 : if (IsA(setOp, RangeTblRef))
229 : : {
230 : 12957 : RangeTblRef *rtr = (RangeTblRef *) setOp;
231 : 12957 : RangeTblEntry *rte = root->simple_rte_array[rtr->rtindex];
232 : 12957 : Query *subquery = rte->subquery;
233 : : PlannerInfo *subroot;
234 : : List *tlist;
235 : : bool trivial_tlist;
236 : : char *plan_name;
237 : :
238 : : Assert(subquery != NULL);
239 : :
240 : : /* Build a RelOptInfo for this leaf subquery. */
241 : 12957 : rel = build_simple_rel(root, rtr->rtindex, NULL);
242 : :
243 : : /* plan_params should not be in use in current query level */
244 : : Assert(root->plan_params == NIL);
245 : :
246 : : /*
247 : : * Generate a subroot and Paths for the subquery. If we have a
248 : : * parentOp, pass that down to encourage subquery_planner to consider
249 : : * suitably-sorted Paths.
250 : : */
251 : 12957 : plan_name = choose_plan_name(root->glob, "setop", true);
252 : 12957 : subroot = rel->subroot = subquery_planner(root->glob, subquery,
253 : : plan_name, root, NULL,
254 : : false, root->tuple_fraction,
255 : : parentOp);
256 : :
257 : : /*
258 : : * It should not be possible for the primitive query to contain any
259 : : * cross-references to other primitive queries in the setop tree.
260 : : */
261 [ - + ]: 12957 : if (root->plan_params)
262 [ # # ]: 0 : elog(ERROR, "unexpected outer reference in set operation subquery");
263 : :
264 : : /* Figure out the appropriate target list for this subquery. */
265 : 12957 : tlist = generate_setop_tlist(colTypes, colCollations,
266 : 12957 : rtr->rtindex,
267 : : true,
268 : : subroot->processed_tlist,
269 : : refnames_tlist,
270 : : &trivial_tlist);
271 : 12957 : rel->reltarget = create_pathtarget(root, tlist);
272 : :
273 : : /* Return the fully-fledged tlist to caller, too */
274 : 12957 : *pTargetList = tlist;
275 : 12957 : *istrivial_tlist = trivial_tlist;
276 : : }
277 [ + - ]: 4343 : else if (IsA(setOp, SetOperationStmt))
278 : : {
279 : 4343 : SetOperationStmt *op = (SetOperationStmt *) setOp;
280 : :
281 : : /* UNIONs are much different from INTERSECT/EXCEPT */
282 [ + + ]: 4343 : if (op->op == SETOP_UNION)
283 : 3719 : rel = generate_union_paths(op, root,
284 : : refnames_tlist,
285 : : pTargetList);
286 : : else
287 : 624 : rel = generate_nonunion_paths(op, root,
288 : : refnames_tlist,
289 : : pTargetList);
290 : :
291 : : /*
292 : : * If necessary, add a Result node to project the caller-requested
293 : : * output columns.
294 : : *
295 : : * XXX you don't really want to know about this: setrefs.c will apply
296 : : * fix_upper_expr() to the Result node's tlist. This would fail if the
297 : : * Vars generated by generate_setop_tlist() were not exactly equal()
298 : : * to the corresponding tlist entries of the subplan. However, since
299 : : * the subplan was generated by generate_union_paths() or
300 : : * generate_nonunion_paths(), and hence its tlist was generated by
301 : : * generate_append_tlist() or generate_setop_tlist(), this will work.
302 : : * We just tell generate_setop_tlist() to use varno 0.
303 : : */
304 [ + + ]: 4343 : if (!tlist_same_datatypes(*pTargetList, colTypes, false) ||
305 [ - + ]: 4328 : !tlist_same_collations(*pTargetList, colCollations, false))
306 : : {
307 : : PathTarget *target;
308 : : bool trivial_tlist;
309 : : ListCell *lc;
310 : :
311 : 15 : *pTargetList = generate_setop_tlist(colTypes, colCollations,
312 : : 0,
313 : : false,
314 : : *pTargetList,
315 : : refnames_tlist,
316 : : &trivial_tlist);
317 : 15 : *istrivial_tlist = trivial_tlist;
318 : 15 : target = create_pathtarget(root, *pTargetList);
319 : :
320 : : /* Apply projection to each path */
321 [ + - + + : 30 : foreach(lc, rel->pathlist)
+ + ]
322 : : {
323 : 15 : Path *subpath = (Path *) lfirst(lc);
324 : : Path *path;
325 : :
326 : : Assert(subpath->param_info == NULL);
327 : 15 : path = apply_projection_to_path(root, subpath->parent,
328 : : subpath, target);
329 : : /* If we had to add a Result, path is different from subpath */
330 [ + - ]: 15 : if (path != subpath)
331 : 15 : lfirst(lc) = path;
332 : : }
333 : :
334 : : /* Apply projection to each partial path */
335 [ - + - - : 15 : foreach(lc, rel->partial_pathlist)
- + ]
336 : : {
337 : 0 : Path *subpath = (Path *) lfirst(lc);
338 : : Path *path;
339 : :
340 : : Assert(subpath->param_info == NULL);
341 : :
342 : : /* avoid apply_projection_to_path, in case of multiple refs */
343 : 0 : path = (Path *) create_projection_path(root, subpath->parent,
344 : : subpath, target);
345 : 0 : lfirst(lc) = path;
346 : : }
347 : : }
348 : 4343 : postprocess_setop_rel(root, rel);
349 : : }
350 : : else
351 : : {
352 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d",
353 : : (int) nodeTag(setOp));
354 : : *pTargetList = NIL;
355 : : rel = NULL; /* keep compiler quiet */
356 : : }
357 : :
358 : 17300 : return rel;
359 : : }
360 : :
361 : : /*
362 : : * Generate paths for a recursive UNION node
363 : : */
364 : : static RelOptInfo *
365 : 637 : generate_recursion_path(SetOperationStmt *setOp, PlannerInfo *root,
366 : : List *refnames_tlist,
367 : : List **pTargetList)
368 : : {
369 : : RelOptInfo *result_rel;
370 : : Path *path;
371 : : RelOptInfo *lrel,
372 : : *rrel;
373 : : Path *lpath;
374 : : Path *rpath;
375 : : List *lpath_tlist;
376 : : bool lpath_trivial_tlist;
377 : : List *rpath_tlist;
378 : : bool rpath_trivial_tlist;
379 : : List *tlist;
380 : : List *groupList;
381 : : double dNumGroups;
382 : :
383 : : /* Parser should have rejected other cases */
384 [ - + ]: 637 : if (setOp->op != SETOP_UNION)
385 [ # # ]: 0 : elog(ERROR, "only UNION queries can be recursive");
386 : : /* Worktable ID should be assigned */
387 : : Assert(root->wt_param_id >= 0);
388 : :
389 : : /*
390 : : * Unlike a regular UNION node, process the left and right inputs
391 : : * separately without any intention of combining them into one Append.
392 : : */
393 : 637 : lrel = recurse_set_operations(setOp->larg, root,
394 : : NULL, /* no value in sorted results */
395 : : setOp->colTypes, setOp->colCollations,
396 : : refnames_tlist,
397 : : &lpath_tlist,
398 : : &lpath_trivial_tlist);
399 [ + - ]: 637 : if (lrel->rtekind == RTE_SUBQUERY)
400 : 637 : build_setop_child_paths(root, lrel, lpath_trivial_tlist, lpath_tlist,
401 : : NIL, NULL);
402 : 637 : lpath = lrel->cheapest_total_path;
403 : : /* The right path will want to look at the left one ... */
404 : 637 : root->non_recursive_path = lpath;
405 : 637 : rrel = recurse_set_operations(setOp->rarg, root,
406 : : NULL, /* no value in sorted results */
407 : : setOp->colTypes, setOp->colCollations,
408 : : refnames_tlist,
409 : : &rpath_tlist,
410 : : &rpath_trivial_tlist);
411 [ + + ]: 637 : if (rrel->rtekind == RTE_SUBQUERY)
412 : 632 : build_setop_child_paths(root, rrel, rpath_trivial_tlist, rpath_tlist,
413 : : NIL, NULL);
414 : 637 : rpath = rrel->cheapest_total_path;
415 : 637 : root->non_recursive_path = NULL;
416 : :
417 : : /*
418 : : * Generate tlist for RecursiveUnion path node --- same as in Append cases
419 : : */
420 : 637 : tlist = generate_append_tlist(setOp->colTypes, setOp->colCollations,
421 : : list_make2(lpath_tlist, rpath_tlist),
422 : : refnames_tlist);
423 : :
424 : 637 : *pTargetList = tlist;
425 : :
426 : : /* Build result relation. */
427 : 637 : result_rel = fetch_upper_rel(root, UPPERREL_SETOP,
428 : 637 : bms_union(lrel->relids, rrel->relids));
429 : 637 : result_rel->reltarget = create_pathtarget(root, tlist);
430 : :
431 : : /*
432 : : * If UNION, identify the grouping operators
433 : : */
434 [ + + ]: 637 : if (setOp->all)
435 : : {
436 : 417 : groupList = NIL;
437 : 417 : dNumGroups = 0;
438 : : }
439 : : else
440 : : {
441 : : /* Identify the grouping semantics */
442 : 220 : groupList = generate_setop_grouplist(setOp, tlist);
443 : :
444 : : /* We only support hashing here */
445 [ + + ]: 220 : if (!grouping_is_hashable(groupList))
446 [ + - ]: 4 : ereport(ERROR,
447 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
448 : : errmsg("could not implement recursive UNION"),
449 : : errdetail("All column datatypes must be hashable.")));
450 : :
451 : : /*
452 : : * For the moment, take the number of distinct groups as equal to the
453 : : * total input size, ie, the worst case.
454 : : */
455 : 216 : dNumGroups = lpath->rows + rpath->rows * 10;
456 : : }
457 : :
458 : : /*
459 : : * And make the path node.
460 : : */
461 : 633 : path = (Path *) create_recursiveunion_path(root,
462 : : result_rel,
463 : : lpath,
464 : : rpath,
465 : 633 : result_rel->reltarget,
466 : : groupList,
467 : : root->wt_param_id,
468 : : dNumGroups);
469 : :
470 : 633 : add_path(result_rel, path);
471 : 633 : postprocess_setop_rel(root, result_rel);
472 : 633 : return result_rel;
473 : : }
474 : :
475 : : /*
476 : : * build_setop_child_paths
477 : : * Build paths for the set op child relation denoted by 'rel'.
478 : : *
479 : : * 'rel' is an RTE_SUBQUERY relation. We have already generated paths within
480 : : * the subquery's subroot; the task here is to create SubqueryScan paths for
481 : : * 'rel', representing scans of the useful subquery paths.
482 : : *
483 : : * interesting_pathkeys: if not NIL, also include paths that suit these
484 : : * pathkeys, sorting any unsorted paths as required.
485 : : * *pNumGroups: if not NULL, we estimate the number of distinct groups
486 : : * in the result, and store it there.
487 : : */
488 : : static void
489 : 12957 : build_setop_child_paths(PlannerInfo *root, RelOptInfo *rel,
490 : : bool trivial_tlist, List *child_tlist,
491 : : List *interesting_pathkeys, double *pNumGroups)
492 : : {
493 : : RelOptInfo *final_rel;
494 : 12957 : List *setop_pathkeys = rel->subroot->setop_pathkeys;
495 : : ListCell *lc;
496 : :
497 : : /* it can't be a set op child rel if it's not a subquery */
498 : : Assert(rel->rtekind == RTE_SUBQUERY);
499 : :
500 : : /* when sorting is needed, add child rel equivalences */
501 [ + + ]: 12957 : if (interesting_pathkeys != NIL)
502 : 10208 : add_setop_child_rel_equivalences(root,
503 : : rel,
504 : : child_tlist,
505 : : interesting_pathkeys);
506 : :
507 : : /*
508 : : * Mark rel with estimated output rows, width, etc. Note that we have to
509 : : * do this before generating outer-query paths, else cost_subqueryscan is
510 : : * not happy.
511 : : */
512 : 12957 : set_subquery_size_estimates(root, rel);
513 : :
514 : : /*
515 : : * Since we may want to add a partial path to this relation, we must set
516 : : * its consider_parallel flag correctly.
517 : : */
518 : 12957 : final_rel = fetch_upper_rel(rel->subroot, UPPERREL_FINAL, NULL);
519 : 12957 : rel->consider_parallel = final_rel->consider_parallel;
520 : :
521 : : /* Generate subquery scan paths for any interesting path in final_rel */
522 [ + - + + : 33959 : foreach(lc, final_rel->pathlist)
+ + ]
523 : : {
524 : 21002 : Path *subpath = (Path *) lfirst(lc);
525 : : List *pathkeys;
526 : 21002 : Path *cheapest_input_path = final_rel->cheapest_total_path;
527 : : bool is_sorted;
528 : : int presorted_keys;
529 : :
530 : : /* If the input rel is dummy, propagate that to this query level */
531 [ + + ]: 21002 : if (is_dummy_rel(final_rel))
532 : : {
533 : 68 : mark_dummy_rel(rel);
534 : 2845 : continue;
535 : : }
536 : :
537 : : /*
538 : : * Include the cheapest path as-is so that the set operation can be
539 : : * cheaply implemented using a method which does not require the input
540 : : * to be sorted.
541 : : */
542 [ + + ]: 20934 : if (subpath == cheapest_input_path)
543 : : {
544 : : /* Convert subpath's pathkeys to outer representation */
545 : 12889 : pathkeys = convert_subquery_pathkeys(root, rel, subpath->pathkeys,
546 : : make_tlist_from_pathtarget(subpath->pathtarget));
547 : :
548 : : /* Generate outer path using this subpath */
549 : 12889 : add_path(rel, (Path *) create_subqueryscan_path(root,
550 : : rel,
551 : : subpath,
552 : : trivial_tlist,
553 : : pathkeys,
554 : : NULL));
555 : : }
556 : :
557 : : /* skip dealing with sorted paths if the setop doesn't need them */
558 [ + + ]: 20934 : if (interesting_pathkeys == NIL)
559 : 2767 : continue;
560 : :
561 : : /*
562 : : * Create paths to suit final sort order required for setop_pathkeys.
563 : : * Here we'll sort the cheapest input path (if not sorted already) and
564 : : * incremental sort any paths which are partially sorted.
565 : : */
566 : 18167 : is_sorted = pathkeys_count_contained_in(setop_pathkeys,
567 : : subpath->pathkeys,
568 : : &presorted_keys);
569 : :
570 [ + + ]: 18167 : if (!is_sorted)
571 : : {
572 : 12054 : double limittuples = rel->subroot->limit_tuples;
573 : :
574 : : /*
575 : : * Try at least sorting the cheapest path and also try
576 : : * incrementally sorting any path which is partially sorted
577 : : * already (no need to deal with paths which have presorted keys
578 : : * when incremental sort is disabled unless it's the cheapest
579 : : * input path).
580 : : */
581 [ + + ]: 12054 : if (subpath != cheapest_input_path &&
582 [ + + - + ]: 2676 : (presorted_keys == 0 || !enable_incremental_sort))
583 : 10 : continue;
584 : :
585 : : /*
586 : : * We've no need to consider both a sort and incremental sort.
587 : : * We'll just do a sort if there are no presorted keys and an
588 : : * incremental sort when there are presorted keys.
589 : : */
590 [ + + + + ]: 12044 : if (presorted_keys == 0 || !enable_incremental_sort)
591 : 9378 : subpath = (Path *) create_sort_path(rel->subroot,
592 : : final_rel,
593 : : subpath,
594 : : setop_pathkeys,
595 : : limittuples);
596 : : else
597 : 2666 : subpath = (Path *) create_incremental_sort_path(rel->subroot,
598 : : final_rel,
599 : : subpath,
600 : : setop_pathkeys,
601 : : presorted_keys,
602 : : limittuples);
603 : : }
604 : :
605 : : /*
606 : : * subpath is now sorted, so add it to the pathlist. We already added
607 : : * the cheapest_input_path above, so don't add it again unless we just
608 : : * sorted it.
609 : : */
610 [ + + ]: 18157 : if (subpath != cheapest_input_path)
611 : : {
612 : : /* Convert subpath's pathkeys to outer representation */
613 : 17387 : pathkeys = convert_subquery_pathkeys(root, rel, subpath->pathkeys,
614 : : make_tlist_from_pathtarget(subpath->pathtarget));
615 : :
616 : : /* Generate outer path using this subpath */
617 : 17387 : add_path(rel, (Path *) create_subqueryscan_path(root,
618 : : rel,
619 : : subpath,
620 : : trivial_tlist,
621 : : pathkeys,
622 : : NULL));
623 : : }
624 : : }
625 : :
626 : : /* if consider_parallel is false, there should be no partial paths */
627 : : Assert(final_rel->consider_parallel ||
628 : : final_rel->partial_pathlist == NIL);
629 : :
630 : : /*
631 : : * If we have a partial path for the child relation, we can use that to
632 : : * build a partial path for this relation. But there's no point in
633 : : * considering any path but the cheapest.
634 : : */
635 [ + + + - ]: 12957 : if (rel->consider_parallel && bms_is_empty(rel->lateral_relids) &&
636 [ + + ]: 8961 : final_rel->partial_pathlist != NIL)
637 : : {
638 : : Path *partial_subpath;
639 : : Path *partial_path;
640 : :
641 : 15 : partial_subpath = linitial(final_rel->partial_pathlist);
642 : : partial_path = (Path *)
643 : 15 : create_subqueryscan_path(root, rel, partial_subpath,
644 : : trivial_tlist,
645 : : NIL, NULL);
646 : 15 : add_partial_path(rel, partial_path);
647 : : }
648 : :
649 : 12957 : postprocess_setop_rel(root, rel);
650 : :
651 : : /*
652 : : * Estimate number of groups if caller wants it. If the subquery used
653 : : * grouping or aggregation, its output is probably mostly unique anyway;
654 : : * otherwise do statistical estimation.
655 : : *
656 : : * XXX you don't really want to know about this: we do the estimation
657 : : * using the subroot->parse's original targetlist expressions, not the
658 : : * subroot->processed_tlist which might seem more appropriate. The reason
659 : : * is that if the subquery is itself a setop, it may return a
660 : : * processed_tlist containing "varno 0" Vars generated by
661 : : * generate_append_tlist, and those would confuse estimate_num_groups
662 : : * mightily. We ought to get rid of the "varno 0" hack, but that requires
663 : : * a redesign of the parsetree representation of setops, so that there can
664 : : * be an RTE corresponding to each setop's output. Note, we use this not
665 : : * subquery's targetlist but subroot->parse's targetlist, because it was
666 : : * revised by self-join removal. subquery's targetlist might contain the
667 : : * references to the removed relids.
668 : : */
669 [ + + ]: 12957 : if (pNumGroups)
670 : : {
671 : 10498 : PlannerInfo *subroot = rel->subroot;
672 : 10498 : Query *subquery = subroot->parse;
673 : :
674 [ + - + - ]: 10498 : if (subquery->groupClause || subquery->groupingSets ||
675 [ + + + - ]: 10498 : subquery->distinctClause || subroot->hasHavingQual ||
676 [ - + ]: 10488 : subquery->hasAggs)
677 : 10 : *pNumGroups = rel->cheapest_total_path->rows;
678 : : else
679 : 10488 : *pNumGroups = estimate_num_groups(subroot,
680 : 10488 : get_tlist_exprs(subroot->parse->targetList, false),
681 : 10488 : rel->cheapest_total_path->rows,
682 : : NULL,
683 : : NULL);
684 : : }
685 : 12957 : }
686 : :
687 : : /*
688 : : * Generate paths for a UNION or UNION ALL node
689 : : */
690 : : static RelOptInfo *
691 : 3719 : generate_union_paths(SetOperationStmt *op, PlannerInfo *root,
692 : : List *refnames_tlist,
693 : : List **pTargetList)
694 : : {
695 : 3719 : Relids relids = NULL;
696 : : RelOptInfo *result_rel;
697 : : ListCell *lc;
698 : : ListCell *lc2;
699 : : ListCell *lc3;
700 : 3719 : AppendPathInput cheapest = {0};
701 : 3719 : AppendPathInput ordered = {0};
702 : 3719 : AppendPathInput partial = {0};
703 : 3719 : bool partial_paths_valid = true;
704 : 3719 : bool consider_parallel = true;
705 : : List *rellist;
706 : : List *tlist_list;
707 : : List *trivial_tlist_list;
708 : : List *tlist;
709 : 3719 : List *groupList = NIL;
710 : : Path *apath;
711 : 3719 : Path *gpath = NULL;
712 : 3719 : bool try_sorted = false;
713 : 3719 : List *union_pathkeys = NIL;
714 : 3719 : double dNumChildGroups = 0;
715 : :
716 : : /*
717 : : * If any of my children are identical UNION nodes (same op, all-flag, and
718 : : * colTypes/colCollations) then they can be merged into this node so that
719 : : * we generate only one Append/MergeAppend and unique-ification for the
720 : : * lot. Recurse to find such nodes.
721 : : */
722 : 3719 : rellist = plan_union_children(root,
723 : : op,
724 : : refnames_tlist,
725 : : &tlist_list,
726 : : &trivial_tlist_list);
727 : :
728 : : /*
729 : : * Generate tlist for Append/MergeAppend plan node.
730 : : *
731 : : * The tlist for an Append plan isn't important as far as the Append is
732 : : * concerned, but we must make it look real anyway for the benefit of the
733 : : * next plan level up.
734 : : */
735 : 3719 : tlist = generate_append_tlist(op->colTypes, op->colCollations,
736 : : tlist_list, refnames_tlist);
737 : 3719 : *pTargetList = tlist;
738 : :
739 : : /* For UNIONs (not UNION ALL), try sorting, if sorting is possible */
740 [ + + ]: 3719 : if (!op->all)
741 : : {
742 : : /* Identify the grouping semantics */
743 : 3274 : groupList = generate_setop_grouplist(op, tlist);
744 : :
745 [ + + ]: 3274 : if (grouping_is_sortable(op->groupClauses))
746 : : {
747 : 3214 : try_sorted = true;
748 : : /* Determine the pathkeys for sorting by the whole target list */
749 : 3214 : union_pathkeys = make_pathkeys_for_sortclauses(root, groupList,
750 : : tlist);
751 : :
752 : 3214 : root->query_pathkeys = union_pathkeys;
753 : : }
754 : : }
755 : :
756 : : /*
757 : : * Now that we've got the append target list, we can build the union child
758 : : * paths.
759 : : */
760 [ + - + + : 14299 : forthree(lc, rellist, lc2, trivial_tlist_list, lc3, tlist_list)
+ - + + +
- + + + +
+ - + - +
+ ]
761 : : {
762 : 10580 : RelOptInfo *rel = lfirst(lc);
763 : 10580 : bool trivial_tlist = lfirst_int(lc2);
764 : 10580 : List *child_tlist = lfirst_node(List, lc3);
765 : 10580 : double childGroups = 0;
766 : :
767 : : /* only build paths for the union children */
768 [ + + ]: 10580 : if (rel->rtekind == RTE_SUBQUERY)
769 : 10470 : build_setop_child_paths(root, rel, trivial_tlist, child_tlist,
770 : : union_pathkeys,
771 [ + + ]: 10470 : op->all ? NULL : &childGroups);
772 : : else
773 : 110 : childGroups = rel->rows;
774 : :
775 : : /*
776 : : * For UNION (not UNION ALL), accumulate the per-child distinct-group
777 : : * estimates. This sum is the basis for the UNION's output estimate
778 : : * below: since distinct(A union B) <= distinct(A) + distinct(B), the
779 : : * union cannot have more distinct rows than its children do in total.
780 : : * Children that are known to be empty contribute nothing, so skip
781 : : * them.
782 : : */
783 [ + + + + ]: 10580 : if (!op->all && !is_dummy_rel(rel))
784 : 9260 : dNumChildGroups += childGroups;
785 : : }
786 : :
787 : : /* Build path lists and relid set. */
788 [ + - + + : 14299 : foreach(lc, rellist)
+ + ]
789 : : {
790 : 10580 : RelOptInfo *rel = lfirst(lc);
791 : : Path *ordered_path;
792 : :
793 : : /*
794 : : * Record the relids so that we can identify the correct
795 : : * UPPERREL_SETOP RelOptInfo below.
796 : : */
797 : 10580 : relids = bms_add_members(relids, rel->relids);
798 : :
799 : : /* Skip any UNION children that are proven not to yield any rows */
800 [ + + ]: 10580 : if (is_dummy_rel(rel))
801 : 38 : continue;
802 : :
803 : 21084 : cheapest.subpaths = lappend(cheapest.subpaths,
804 : 10542 : rel->cheapest_total_path);
805 : :
806 [ + + ]: 10542 : if (try_sorted)
807 : : {
808 : 3476 : ordered_path = get_cheapest_path_for_pathkeys(rel->pathlist,
809 : : union_pathkeys,
810 : : NULL,
811 : : TOTAL_COST,
812 : : false);
813 : :
814 [ + + ]: 3476 : if (ordered_path != NULL)
815 : 519 : ordered.subpaths = lappend(ordered.subpaths, ordered_path);
816 : : else
817 : : {
818 : : /*
819 : : * If we can't find a sorted path, just give up trying to
820 : : * generate a list of correctly sorted child paths. This can
821 : : * happen when type coercion was added to the targetlist due
822 : : * to mismatching types from the union children.
823 : : */
824 : 2957 : try_sorted = false;
825 : : }
826 : : }
827 : :
828 [ + + ]: 10542 : if (consider_parallel)
829 : : {
830 [ + + ]: 7602 : if (!rel->consider_parallel)
831 : : {
832 : 2825 : consider_parallel = false;
833 : 2825 : partial_paths_valid = false;
834 : : }
835 [ + + ]: 4777 : else if (rel->partial_pathlist == NIL)
836 : 4767 : partial_paths_valid = false;
837 : : else
838 : 10 : partial.partial_subpaths = lappend(partial.partial_subpaths,
839 : 10 : linitial(rel->partial_pathlist));
840 : : }
841 : : }
842 : :
843 : : /* Build result relation. */
844 : 3719 : result_rel = fetch_upper_rel(root, UPPERREL_SETOP, relids);
845 : 3719 : result_rel->reltarget = create_setop_pathtarget(root, tlist,
846 : : cheapest.subpaths);
847 : 3719 : result_rel->consider_parallel = consider_parallel;
848 : 3719 : result_rel->consider_startup = (root->tuple_fraction > 0);
849 : :
850 : : /* If all UNION children were dummy rels, make the resulting rel dummy */
851 [ + + ]: 3719 : if (cheapest.subpaths == NIL)
852 : : {
853 : 5 : mark_dummy_rel(result_rel);
854 : :
855 : 5 : return result_rel;
856 : : }
857 : :
858 : : /*
859 : : * Append the child results together using the cheapest paths from each
860 : : * union child.
861 : : */
862 : 3714 : apath = (Path *) create_append_path(root, result_rel, cheapest,
863 : : NIL, NULL, 0, false, -1);
864 : :
865 : : /*
866 : : * Initialize the result row estimate to the total input size. This is
867 : : * correct for UNION ALL; for the UNION case it is overwritten below with
868 : : * the estimated number of distinct groups.
869 : : */
870 : 3714 : result_rel->rows = apath->rows;
871 : :
872 : : /*
873 : : * Now consider doing the same thing using the partial paths plus Append
874 : : * plus Gather.
875 : : */
876 [ + + ]: 3714 : if (partial_paths_valid)
877 : : {
878 : : Path *papath;
879 : 5 : int parallel_workers = 0;
880 : :
881 : : /* Find the highest number of workers requested for any subpath. */
882 [ + - + + : 15 : foreach(lc, partial.partial_subpaths)
+ + ]
883 : : {
884 : 10 : Path *subpath = lfirst(lc);
885 : :
886 : 10 : parallel_workers = Max(parallel_workers,
887 : : subpath->parallel_workers);
888 : : }
889 : : Assert(parallel_workers > 0);
890 : :
891 : : /*
892 : : * If the use of parallel append is permitted, always request at least
893 : : * log2(# of children) paths. We assume it can be useful to have
894 : : * extra workers in this case because they will be spread out across
895 : : * the children. The precise formula is just a guess; see
896 : : * add_paths_to_append_rel.
897 : : */
898 [ + - ]: 5 : if (enable_parallel_append)
899 : : {
900 [ + - ]: 5 : parallel_workers = Max(parallel_workers,
901 : : pg_leftmost_one_pos32(list_length(partial.partial_subpaths)) + 1);
902 : 5 : parallel_workers = Min(parallel_workers,
903 : : max_parallel_workers_per_gather);
904 : : }
905 : : Assert(parallel_workers > 0);
906 : :
907 : : papath = (Path *)
908 : 5 : create_append_path(root, result_rel, partial,
909 : : NIL, NULL, parallel_workers,
910 : : enable_parallel_append, -1);
911 : : gpath = (Path *)
912 : 5 : create_gather_path(root, result_rel, papath,
913 : 5 : result_rel->reltarget, NULL, NULL);
914 : : }
915 : :
916 [ + + ]: 3714 : if (!op->all)
917 : : {
918 : 3269 : bool can_sort = grouping_is_sortable(groupList);
919 : 3269 : bool can_hash = grouping_is_hashable(groupList);
920 : :
921 : : /*
922 : : * result_rel->rows was initialized to the total input size above,
923 : : * which is the correct estimate for UNION ALL. A UNION removes
924 : : * duplicates, so override it with the estimated number of distinct
925 : : * groups.
926 : : */
927 : 3269 : result_rel->rows = dNumChildGroups;
928 : :
929 [ + + ]: 3269 : if (can_hash)
930 : : {
931 : : Path *path;
932 : :
933 : : /*
934 : : * Try a hash aggregate plan on 'apath'. This is the cheapest
935 : : * available path containing each append child.
936 : : */
937 : 3209 : path = (Path *) create_agg_path(root,
938 : : result_rel,
939 : : apath,
940 : 3209 : result_rel->reltarget,
941 : : AGG_HASHED,
942 : : AGGSPLIT_SIMPLE,
943 : : groupList,
944 : : NIL,
945 : : NULL,
946 : : dNumChildGroups);
947 : 3209 : add_path(result_rel, path);
948 : :
949 : : /* Try hash aggregate on the Gather path, if valid */
950 [ + + ]: 3209 : if (gpath != NULL)
951 : : {
952 : : /* Hashed aggregate plan --- no sort needed */
953 : 5 : path = (Path *) create_agg_path(root,
954 : : result_rel,
955 : : gpath,
956 : 5 : result_rel->reltarget,
957 : : AGG_HASHED,
958 : : AGGSPLIT_SIMPLE,
959 : : groupList,
960 : : NIL,
961 : : NULL,
962 : : dNumChildGroups);
963 : 5 : add_path(result_rel, path);
964 : : }
965 : : }
966 : :
967 [ + + ]: 3269 : if (can_sort)
968 : : {
969 : 3209 : Path *path = apath;
970 : :
971 : : /* Try Sort -> Unique on the Append path */
972 [ + + ]: 3209 : if (groupList != NIL)
973 : 3184 : path = (Path *) create_sort_path(root, result_rel, path,
974 : : make_pathkeys_for_sortclauses(root, groupList, tlist),
975 : : -1.0);
976 : :
977 : 3209 : path = (Path *) create_unique_path(root,
978 : : result_rel,
979 : : path,
980 : 3209 : list_length(path->pathkeys),
981 : : dNumChildGroups);
982 : :
983 : 3209 : add_path(result_rel, path);
984 : :
985 : : /* Try Sort -> Unique on the Gather path, if set */
986 [ + + ]: 3209 : if (gpath != NULL)
987 : : {
988 : 5 : path = gpath;
989 : :
990 : 5 : path = (Path *) create_sort_path(root, result_rel, path,
991 : : make_pathkeys_for_sortclauses(root, groupList, tlist),
992 : : -1.0);
993 : :
994 : 5 : path = (Path *) create_unique_path(root,
995 : : result_rel,
996 : : path,
997 : 5 : list_length(path->pathkeys),
998 : : dNumChildGroups);
999 : 5 : add_path(result_rel, path);
1000 : : }
1001 : : }
1002 : :
1003 : : /*
1004 : : * Try making a MergeAppend path if we managed to find a path with the
1005 : : * correct pathkeys in each union child query.
1006 : : */
1007 [ + + + + ]: 3269 : if (try_sorted && groupList != NIL)
1008 : : {
1009 : : Path *path;
1010 : :
1011 : 227 : path = (Path *) create_merge_append_path(root,
1012 : : result_rel,
1013 : : ordered.subpaths,
1014 : : NIL,
1015 : : union_pathkeys,
1016 : : NULL);
1017 : :
1018 : : /* and make the MergeAppend unique */
1019 : 227 : path = (Path *) create_unique_path(root,
1020 : : result_rel,
1021 : : path,
1022 : : list_length(tlist),
1023 : : dNumChildGroups);
1024 : :
1025 : 227 : add_path(result_rel, path);
1026 : : }
1027 : : }
1028 : : else
1029 : : {
1030 : : /* UNION ALL */
1031 : 445 : add_path(result_rel, apath);
1032 : :
1033 [ - + ]: 445 : if (gpath != NULL)
1034 : 0 : add_path(result_rel, gpath);
1035 : : }
1036 : :
1037 : 3714 : return result_rel;
1038 : : }
1039 : :
1040 : : /*
1041 : : * Generate paths for an INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL node
1042 : : */
1043 : : static RelOptInfo *
1044 : 624 : generate_nonunion_paths(SetOperationStmt *op, PlannerInfo *root,
1045 : : List *refnames_tlist,
1046 : : List **pTargetList)
1047 : : {
1048 : : RelOptInfo *result_rel;
1049 : : RelOptInfo *lrel,
1050 : : *rrel;
1051 : 624 : double save_fraction = root->tuple_fraction;
1052 : : Path *lpath,
1053 : : *rpath,
1054 : : *path;
1055 : : List *lpath_tlist,
1056 : : *rpath_tlist,
1057 : : *tlist,
1058 : : *groupList;
1059 : : bool lpath_trivial_tlist,
1060 : : rpath_trivial_tlist,
1061 : : result_trivial_tlist;
1062 : 624 : List *nonunion_pathkeys = NIL;
1063 : : double dLeftGroups,
1064 : : dRightGroups,
1065 : : dNumGroups,
1066 : : dNumOutputRows;
1067 : : bool can_sort;
1068 : : bool can_hash;
1069 : : SetOpCmd cmd;
1070 : :
1071 : : /*
1072 : : * Tell children to fetch all tuples.
1073 : : */
1074 : 624 : root->tuple_fraction = 0.0;
1075 : :
1076 : : /* Recurse on children */
1077 : 624 : lrel = recurse_set_operations(op->larg, root,
1078 : : op,
1079 : : op->colTypes, op->colCollations,
1080 : : refnames_tlist,
1081 : : &lpath_tlist,
1082 : : &lpath_trivial_tlist);
1083 : :
1084 : 624 : rrel = recurse_set_operations(op->rarg, root,
1085 : : op,
1086 : : op->colTypes, op->colCollations,
1087 : : refnames_tlist,
1088 : : &rpath_tlist,
1089 : : &rpath_trivial_tlist);
1090 : :
1091 : : /*
1092 : : * Generate tlist for SetOp plan node.
1093 : : *
1094 : : * The tlist for a SetOp plan isn't important so far as the SetOp is
1095 : : * concerned, but we must make it look real anyway for the benefit of the
1096 : : * next plan level up.
1097 : : */
1098 : 624 : tlist = generate_setop_tlist(op->colTypes, op->colCollations,
1099 : : 0, false, lpath_tlist, refnames_tlist,
1100 : : &result_trivial_tlist);
1101 : :
1102 : : /* We should not have needed any type coercions in the tlist */
1103 : : Assert(result_trivial_tlist);
1104 : :
1105 : 624 : *pTargetList = tlist;
1106 : :
1107 : : /* Identify the grouping semantics */
1108 : 624 : groupList = generate_setop_grouplist(op, tlist);
1109 : :
1110 : : /* Check whether the operators support sorting or hashing */
1111 : 624 : can_sort = grouping_is_sortable(groupList);
1112 : 624 : can_hash = grouping_is_hashable(groupList);
1113 [ - + - - ]: 624 : if (!can_sort && !can_hash)
1114 [ # # # # ]: 0 : ereport(ERROR,
1115 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1116 : : /* translator: %s is INTERSECT or EXCEPT */
1117 : : errmsg("could not implement %s",
1118 : : (op->op == SETOP_INTERSECT) ? "INTERSECT" : "EXCEPT"),
1119 : : errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
1120 : :
1121 [ + - ]: 624 : if (can_sort)
1122 : : {
1123 : : /* Determine the pathkeys for sorting by the whole target list */
1124 : 624 : nonunion_pathkeys = make_pathkeys_for_sortclauses(root, groupList,
1125 : : tlist);
1126 : :
1127 : 624 : root->query_pathkeys = nonunion_pathkeys;
1128 : : }
1129 : :
1130 : : /*
1131 : : * Now that we've got all that info, we can build the child paths.
1132 : : */
1133 [ + + ]: 624 : if (lrel->rtekind == RTE_SUBQUERY)
1134 : 604 : build_setop_child_paths(root, lrel, lpath_trivial_tlist, lpath_tlist,
1135 : : nonunion_pathkeys, &dLeftGroups);
1136 : : else
1137 : 20 : dLeftGroups = lrel->rows;
1138 [ + + ]: 624 : if (rrel->rtekind == RTE_SUBQUERY)
1139 : 614 : build_setop_child_paths(root, rrel, rpath_trivial_tlist, rpath_tlist,
1140 : : nonunion_pathkeys, &dRightGroups);
1141 : : else
1142 : 10 : dRightGroups = rrel->rows;
1143 : :
1144 : : /* Undo effects of forcing tuple_fraction to 0 */
1145 : 624 : root->tuple_fraction = save_fraction;
1146 : :
1147 : : /*
1148 : : * For EXCEPT, we must put the left input first. For INTERSECT, either
1149 : : * order should give the same results, and we prefer to put the smaller
1150 : : * input first in order to (a) minimize the size of the hash table in the
1151 : : * hashing case, and (b) improve our chances of exploiting the executor's
1152 : : * fast path for empty left-hand input. "Smaller" means the one with the
1153 : : * fewer groups.
1154 : : */
1155 [ + + + + ]: 624 : if (op->op != SETOP_EXCEPT && dLeftGroups > dRightGroups)
1156 : : {
1157 : : /* need to swap the two inputs */
1158 : : RelOptInfo *tmprel;
1159 : : List *tmplist;
1160 : : double tmpd;
1161 : :
1162 : 30 : tmprel = lrel;
1163 : 30 : lrel = rrel;
1164 : 30 : rrel = tmprel;
1165 : 30 : tmplist = lpath_tlist;
1166 : 30 : lpath_tlist = rpath_tlist;
1167 : 30 : rpath_tlist = tmplist;
1168 : 30 : tmpd = dLeftGroups;
1169 : 30 : dLeftGroups = dRightGroups;
1170 : 30 : dRightGroups = tmpd;
1171 : : }
1172 : :
1173 : 624 : lpath = lrel->cheapest_total_path;
1174 : 624 : rpath = rrel->cheapest_total_path;
1175 : :
1176 : : /* Build result relation. */
1177 : 624 : result_rel = fetch_upper_rel(root, UPPERREL_SETOP,
1178 : 624 : bms_union(lrel->relids, rrel->relids));
1179 : :
1180 : : /*
1181 : : * Create the PathTarget and set the width accordingly. For EXCEPT, since
1182 : : * the set op result won't contain rows from the rpath, we only account
1183 : : * for the width of the lpath. For INTERSECT, use both input paths.
1184 : : */
1185 [ + + ]: 624 : if (op->op == SETOP_EXCEPT)
1186 : 419 : result_rel->reltarget = create_setop_pathtarget(root, tlist,
1187 : : list_make1(lpath));
1188 : : else
1189 : 205 : result_rel->reltarget = create_setop_pathtarget(root, tlist,
1190 : : list_make2(lpath, rpath));
1191 : :
1192 : : /* Check for provably empty setop inputs and add short-circuit paths. */
1193 [ + + ]: 624 : if (op->op == SETOP_EXCEPT)
1194 : : {
1195 : : /*
1196 : : * For EXCEPTs, if the left side is dummy then there's no need to
1197 : : * inspect the right-hand side as scanning the right to find tuples to
1198 : : * remove won't make the left-hand input any more empty.
1199 : : */
1200 [ + + ]: 419 : if (is_dummy_rel(lrel))
1201 : : {
1202 : 5 : mark_dummy_rel(result_rel);
1203 : :
1204 : 5 : return result_rel;
1205 : : }
1206 : :
1207 : : /* Handle EXCEPTs with dummy right input */
1208 [ + + ]: 414 : if (is_dummy_rel(rrel))
1209 : : {
1210 [ + - ]: 5 : if (op->all)
1211 : : {
1212 : : Path *apath;
1213 : 5 : AppendPathInput append = {0};
1214 : :
1215 : 5 : append.subpaths = list_make1(lpath);
1216 : :
1217 : : /*
1218 : : * EXCEPT ALL: If the right-hand input is dummy then we can
1219 : : * simply scan the left-hand input. To keep createplan.c
1220 : : * happy, use a single child Append to handle the translation
1221 : : * between the set op targetlist and the targetlist of the
1222 : : * left input. The Append will be removed in setrefs.c.
1223 : : */
1224 : 5 : apath = (Path *) create_append_path(root, result_rel,
1225 : : append, NIL, NULL, 0,
1226 : : false, -1);
1227 : :
1228 : 5 : add_path(result_rel, apath);
1229 : :
1230 : 5 : return result_rel;
1231 : : }
1232 : : else
1233 : : {
1234 : : /*
1235 : : * To make EXCEPT with a dummy RHS work means having to
1236 : : * deduplicate the left input. That could be done with
1237 : : * AggPaths, but it doesn't seem worth the effort. Let the
1238 : : * normal path generation code below handle this one.
1239 : : */
1240 : : }
1241 : : }
1242 : : }
1243 : : else
1244 : : {
1245 : : /*
1246 : : * For INTERSECT, if either input is a dummy rel then we can mark the
1247 : : * result_rel as dummy since intersecting with an empty relation can
1248 : : * never yield any results. This is true regardless of INTERSECT or
1249 : : * INTERSECT ALL.
1250 : : */
1251 [ + + - + ]: 205 : if (is_dummy_rel(lrel) || is_dummy_rel(rrel))
1252 : : {
1253 : 15 : mark_dummy_rel(result_rel);
1254 : :
1255 : 15 : return result_rel;
1256 : : }
1257 : : }
1258 : :
1259 : : /*
1260 : : * Estimate number of distinct groups that we'll need hashtable entries
1261 : : * for; this is the size of the left-hand input for EXCEPT, or the smaller
1262 : : * input for INTERSECT. Also estimate the number of eventual output rows.
1263 : : * In non-ALL cases, we estimate each group produces one output row; in
1264 : : * ALL cases use the relevant relation size. These are worst-case
1265 : : * estimates, of course, but we need to be conservative.
1266 : : */
1267 [ + + ]: 599 : if (op->op == SETOP_EXCEPT)
1268 : : {
1269 : 409 : dNumGroups = dLeftGroups;
1270 [ + + ]: 409 : dNumOutputRows = op->all ? lpath->rows : dNumGroups;
1271 : : }
1272 : : else
1273 : : {
1274 : 190 : dNumGroups = dLeftGroups;
1275 [ + + - + ]: 190 : dNumOutputRows = op->all ? Min(lpath->rows, rpath->rows) : dNumGroups;
1276 : : }
1277 : 599 : result_rel->rows = dNumOutputRows;
1278 : :
1279 : : /* Select the SetOpCmd type */
1280 [ + + - ]: 599 : switch (op->op)
1281 : : {
1282 : 190 : case SETOP_INTERSECT:
1283 : 190 : cmd = op->all ? SETOPCMD_INTERSECT_ALL : SETOPCMD_INTERSECT;
1284 : 190 : break;
1285 : 409 : case SETOP_EXCEPT:
1286 [ + + ]: 409 : cmd = op->all ? SETOPCMD_EXCEPT_ALL : SETOPCMD_EXCEPT;
1287 : 409 : break;
1288 : 0 : default:
1289 [ # # ]: 0 : elog(ERROR, "unrecognized set op: %d", (int) op->op);
1290 : : cmd = SETOPCMD_INTERSECT; /* keep compiler quiet */
1291 : : break;
1292 : : }
1293 : :
1294 : : /*
1295 : : * If we can hash, that just requires a SetOp atop the cheapest inputs.
1296 : : */
1297 [ + + ]: 599 : if (can_hash)
1298 : : {
1299 : 549 : path = (Path *) create_setop_path(root,
1300 : : result_rel,
1301 : : lpath,
1302 : : rpath,
1303 : : cmd,
1304 : : SETOP_HASHED,
1305 : : groupList,
1306 : : dNumGroups,
1307 : : dNumOutputRows);
1308 : 549 : add_path(result_rel, path);
1309 : : }
1310 : :
1311 : : /*
1312 : : * If we can sort, generate the cheapest sorted input paths, and add a
1313 : : * SetOp atop those.
1314 : : */
1315 [ + - ]: 599 : if (can_sort)
1316 : : {
1317 : : List *pathkeys;
1318 : : Path *slpath,
1319 : : *srpath;
1320 : :
1321 : : /* First the left input ... */
1322 : 599 : pathkeys = make_pathkeys_for_sortclauses(root,
1323 : : groupList,
1324 : : lpath_tlist);
1325 [ + + ]: 599 : if (pathkeys_contained_in(pathkeys, lpath->pathkeys))
1326 : 80 : slpath = lpath; /* cheapest path is already sorted */
1327 : : else
1328 : : {
1329 : 519 : slpath = get_cheapest_path_for_pathkeys(lrel->pathlist,
1330 : : nonunion_pathkeys,
1331 : : NULL,
1332 : : TOTAL_COST,
1333 : : false);
1334 : : /* Subquery failed to produce any presorted paths? */
1335 [ + + ]: 519 : if (slpath == NULL)
1336 : 165 : slpath = (Path *) create_sort_path(root,
1337 : : lpath->parent,
1338 : : lpath,
1339 : : pathkeys,
1340 : : -1.0);
1341 : : }
1342 : :
1343 : : /* and now the same for the right. */
1344 : 599 : pathkeys = make_pathkeys_for_sortclauses(root,
1345 : : groupList,
1346 : : rpath_tlist);
1347 [ + + ]: 599 : if (pathkeys_contained_in(pathkeys, rpath->pathkeys))
1348 : 90 : srpath = rpath; /* cheapest path is already sorted */
1349 : : else
1350 : : {
1351 : 509 : srpath = get_cheapest_path_for_pathkeys(rrel->pathlist,
1352 : : nonunion_pathkeys,
1353 : : NULL,
1354 : : TOTAL_COST,
1355 : : false);
1356 : : /* Subquery failed to produce any presorted paths? */
1357 [ + + ]: 509 : if (srpath == NULL)
1358 : 165 : srpath = (Path *) create_sort_path(root,
1359 : : rpath->parent,
1360 : : rpath,
1361 : : pathkeys,
1362 : : -1.0);
1363 : : }
1364 : :
1365 : 599 : path = (Path *) create_setop_path(root,
1366 : : result_rel,
1367 : : slpath,
1368 : : srpath,
1369 : : cmd,
1370 : : SETOP_SORTED,
1371 : : groupList,
1372 : : dNumGroups,
1373 : : dNumOutputRows);
1374 : 599 : add_path(result_rel, path);
1375 : : }
1376 : :
1377 : 599 : return result_rel;
1378 : : }
1379 : :
1380 : : /*
1381 : : * Pull up children of a UNION node that are identically-propertied UNIONs,
1382 : : * and perform planning of the queries underneath the N-way UNION.
1383 : : *
1384 : : * The result is a list of RelOptInfos containing Paths for sub-nodes, with
1385 : : * one entry for each descendant that is a leaf query or non-identical setop.
1386 : : * We also return parallel lists of the childrens' targetlists and
1387 : : * is-trivial-tlist flags.
1388 : : *
1389 : : * NOTE: we can also pull a UNION ALL up into a UNION, since the distinct
1390 : : * output rows will be lost anyway.
1391 : : */
1392 : : static List *
1393 : 3719 : plan_union_children(PlannerInfo *root,
1394 : : SetOperationStmt *top_union,
1395 : : List *refnames_tlist,
1396 : : List **tlist_list,
1397 : : List **istrivial_tlist)
1398 : : {
1399 : 3719 : List *pending_rels = list_make1(top_union);
1400 : 3719 : List *result = NIL;
1401 : : List *child_tlist;
1402 : : bool trivial_tlist;
1403 : :
1404 : 3719 : *tlist_list = NIL;
1405 : 3719 : *istrivial_tlist = NIL;
1406 : :
1407 [ + + ]: 21160 : while (pending_rels != NIL)
1408 : : {
1409 : 17441 : Node *setOp = linitial(pending_rels);
1410 : :
1411 : 17441 : pending_rels = list_delete_first(pending_rels);
1412 : :
1413 [ + + ]: 17441 : if (IsA(setOp, SetOperationStmt))
1414 : : {
1415 : 6971 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1416 : :
1417 [ + + ]: 6971 : if (op->op == top_union->op &&
1418 [ + + + + : 13767 : (op->all == top_union->all || op->all) &&
+ + ]
1419 [ + - ]: 13737 : equal(op->colTypes, top_union->colTypes) &&
1420 : 6861 : equal(op->colCollations, top_union->colCollations))
1421 : : {
1422 : : /* Same UNION, so fold children into parent */
1423 : 6861 : pending_rels = lcons(op->rarg, pending_rels);
1424 : 6861 : pending_rels = lcons(op->larg, pending_rels);
1425 : 6861 : continue;
1426 : : }
1427 : : }
1428 : :
1429 : : /*
1430 : : * Not same, so plan this child separately.
1431 : : *
1432 : : * If top_union isn't a UNION ALL, then we are interested in sorted
1433 : : * output from the child, so pass top_union as parentOp. Note that
1434 : : * this isn't necessarily the child node's immediate SetOperationStmt
1435 : : * parent, but that's fine: it's the effective parent.
1436 : : */
1437 : 10580 : result = lappend(result, recurse_set_operations(setOp, root,
1438 [ + + ]: 10580 : top_union->all ? NULL : top_union,
1439 : : top_union->colTypes,
1440 : : top_union->colCollations,
1441 : : refnames_tlist,
1442 : : &child_tlist,
1443 : : &trivial_tlist));
1444 : 10580 : *tlist_list = lappend(*tlist_list, child_tlist);
1445 : 10580 : *istrivial_tlist = lappend_int(*istrivial_tlist, trivial_tlist);
1446 : : }
1447 : :
1448 : 3719 : return result;
1449 : : }
1450 : :
1451 : : /*
1452 : : * postprocess_setop_rel - perform steps required after adding paths
1453 : : */
1454 : : static void
1455 : 17933 : postprocess_setop_rel(PlannerInfo *root, RelOptInfo *rel)
1456 : : {
1457 : : /*
1458 : : * We don't currently worry about allowing FDWs to contribute paths to
1459 : : * this relation, but give extensions a chance.
1460 : : */
1461 [ - + ]: 17933 : if (create_upper_paths_hook)
1462 : 0 : (*create_upper_paths_hook) (root, UPPERREL_SETOP,
1463 : : NULL, rel, NULL);
1464 : :
1465 : : /* Select cheapest path */
1466 : 17933 : set_cheapest(rel);
1467 : 17933 : }
1468 : :
1469 : : /*
1470 : : * Generate targetlist for a set-operation plan node
1471 : : *
1472 : : * colTypes: OID list of set-op's result column datatypes
1473 : : * colCollations: OID list of set-op's result column collations
1474 : : * varno: varno to use in generated Vars
1475 : : * hack_constants: true to copy up constants (see comments in code)
1476 : : * input_tlist: targetlist of this node's input node
1477 : : * refnames_tlist: targetlist to take column names from
1478 : : * trivial_tlist: output parameter, set to true if targetlist is trivial
1479 : : */
1480 : : static List *
1481 : 13596 : generate_setop_tlist(List *colTypes, List *colCollations,
1482 : : Index varno,
1483 : : bool hack_constants,
1484 : : List *input_tlist,
1485 : : List *refnames_tlist,
1486 : : bool *trivial_tlist)
1487 : : {
1488 : 13596 : List *tlist = NIL;
1489 : 13596 : int resno = 1;
1490 : : ListCell *ctlc,
1491 : : *cclc,
1492 : : *itlc,
1493 : : *rtlc;
1494 : : TargetEntry *tle;
1495 : : Node *expr;
1496 : :
1497 : 13596 : *trivial_tlist = true; /* until proven differently */
1498 : :
1499 [ + + + + : 54379 : forfour(ctlc, colTypes, cclc, colCollations,
+ + + + +
+ + + + +
+ + + + +
- + - + -
+ + ]
1500 : : itlc, input_tlist, rtlc, refnames_tlist)
1501 : : {
1502 : 40783 : Oid colType = lfirst_oid(ctlc);
1503 : 40783 : Oid colColl = lfirst_oid(cclc);
1504 : 40783 : TargetEntry *inputtle = (TargetEntry *) lfirst(itlc);
1505 : 40783 : TargetEntry *reftle = (TargetEntry *) lfirst(rtlc);
1506 : :
1507 : : Assert(inputtle->resno == resno);
1508 : : Assert(reftle->resno == resno);
1509 : : Assert(!inputtle->resjunk);
1510 : : Assert(!reftle->resjunk);
1511 : :
1512 : : /*
1513 : : * Generate columns referencing input columns and having appropriate
1514 : : * data types and column names. Insert datatype coercions where
1515 : : * necessary.
1516 : : *
1517 : : * HACK: constants in the input's targetlist are copied up as-is
1518 : : * rather than being referenced as subquery outputs. This is mainly
1519 : : * to ensure that when we try to coerce them to the output column's
1520 : : * datatype, the right things happen for UNKNOWN constants. But do
1521 : : * this only at the first level of subquery-scan plans; we don't want
1522 : : * phony constants appearing in the output tlists of upper-level
1523 : : * nodes!
1524 : : *
1525 : : * Note that copying a constant doesn't in itself require us to mark
1526 : : * the tlist nontrivial; see trivial_subqueryscan() in setrefs.c.
1527 : : */
1528 [ + + + - : 40783 : if (hack_constants && inputtle->expr && IsA(inputtle->expr, Const))
+ + ]
1529 : 12961 : expr = (Node *) inputtle->expr;
1530 : : else
1531 : 111288 : expr = (Node *) makeVar(varno,
1532 : 27822 : inputtle->resno,
1533 : 27822 : exprType((Node *) inputtle->expr),
1534 : 27822 : exprTypmod((Node *) inputtle->expr),
1535 : 27822 : exprCollation((Node *) inputtle->expr),
1536 : : 0);
1537 : :
1538 [ + + ]: 40783 : if (exprType(expr) != colType)
1539 : : {
1540 : : /*
1541 : : * Note: it's not really cool to be applying coerce_to_common_type
1542 : : * here; one notable point is that assign_expr_collations never
1543 : : * gets run on any generated nodes. For the moment that's not a
1544 : : * problem because we force the correct exposed collation below.
1545 : : * It would likely be best to make the parser generate the correct
1546 : : * output tlist for every set-op to begin with, though.
1547 : : */
1548 : 1124 : expr = coerce_to_common_type(NULL, /* no UNKNOWNs here */
1549 : : expr,
1550 : : colType,
1551 : : "UNION/INTERSECT/EXCEPT");
1552 : 1124 : *trivial_tlist = false; /* the coercion makes it not trivial */
1553 : : }
1554 : :
1555 : : /*
1556 : : * Ensure the tlist entry's exposed collation matches the set-op. This
1557 : : * is necessary because plan_set_operations() reports the result
1558 : : * ordering as a list of SortGroupClauses, which don't carry collation
1559 : : * themselves but just refer to tlist entries. If we don't show the
1560 : : * right collation then planner.c might do the wrong thing in
1561 : : * higher-level queries.
1562 : : *
1563 : : * Note we use RelabelType, not CollateExpr, since this expression
1564 : : * will reach the executor without any further processing.
1565 : : */
1566 [ + + ]: 40783 : if (exprCollation(expr) != colColl)
1567 : : {
1568 : 10915 : expr = applyRelabelType(expr,
1569 : : exprType(expr), exprTypmod(expr), colColl,
1570 : : COERCE_IMPLICIT_CAST, -1, false);
1571 : 10915 : *trivial_tlist = false; /* the relabel makes it not trivial */
1572 : : }
1573 : :
1574 : 81566 : tle = makeTargetEntry((Expr *) expr,
1575 : 40783 : (AttrNumber) resno++,
1576 : 40783 : pstrdup(reftle->resname),
1577 : : false);
1578 : :
1579 : : /*
1580 : : * By convention, all output columns in a setop tree have
1581 : : * ressortgroupref equal to their resno. In some cases the ref isn't
1582 : : * needed, but this is a cleaner way than modifying the tlist later.
1583 : : */
1584 : 40783 : tle->ressortgroupref = tle->resno;
1585 : :
1586 : 40783 : tlist = lappend(tlist, tle);
1587 : : }
1588 : :
1589 : 13596 : return tlist;
1590 : : }
1591 : :
1592 : : /*
1593 : : * Generate targetlist for a set-operation Append node
1594 : : *
1595 : : * colTypes: OID list of set-op's result column datatypes
1596 : : * colCollations: OID list of set-op's result column collations
1597 : : * input_tlists: list of tlists for sub-plans of the Append
1598 : : * refnames_tlist: targetlist to take column names from
1599 : : *
1600 : : * The entries in the Append's targetlist should always be simple Vars;
1601 : : * we just have to make sure they have the right datatypes/typmods/collations.
1602 : : * The Vars are always generated with varno 0.
1603 : : *
1604 : : * XXX a problem with the varno-zero approach is that set_pathtarget_cost_width
1605 : : * cannot figure out a realistic width for the tlist we make here. But we
1606 : : * ought to refactor this code to produce a PathTarget directly, anyway.
1607 : : */
1608 : : static List *
1609 : 4356 : generate_append_tlist(List *colTypes, List *colCollations,
1610 : : List *input_tlists,
1611 : : List *refnames_tlist)
1612 : : {
1613 : 4356 : List *tlist = NIL;
1614 : 4356 : int resno = 1;
1615 : : ListCell *curColType;
1616 : : ListCell *curColCollation;
1617 : : ListCell *ref_tl_item;
1618 : : int colindex;
1619 : : TargetEntry *tle;
1620 : : Node *expr;
1621 : : ListCell *tlistl;
1622 : : int32 *colTypmods;
1623 : :
1624 : : /*
1625 : : * First extract typmods to use.
1626 : : *
1627 : : * If the inputs all agree on type and typmod of a particular column, use
1628 : : * that typmod; else use -1.
1629 : : */
1630 : 4356 : colTypmods = palloc_array(int32, list_length(colTypes));
1631 : :
1632 [ + - + + : 16210 : foreach(tlistl, input_tlists)
+ + ]
1633 : : {
1634 : 11854 : List *subtlist = (List *) lfirst(tlistl);
1635 : : ListCell *subtlistl;
1636 : :
1637 : 11854 : curColType = list_head(colTypes);
1638 : 11854 : colindex = 0;
1639 [ + + + + : 46126 : foreach(subtlistl, subtlist)
+ + ]
1640 : : {
1641 : 34272 : TargetEntry *subtle = (TargetEntry *) lfirst(subtlistl);
1642 : :
1643 : : Assert(!subtle->resjunk);
1644 : : Assert(curColType != NULL);
1645 [ + - ]: 34272 : if (exprType((Node *) subtle->expr) == lfirst_oid(curColType))
1646 : : {
1647 : : /* If first subplan, copy the typmod; else compare */
1648 : 34272 : int32 subtypmod = exprTypmod((Node *) subtle->expr);
1649 : :
1650 [ + + ]: 34272 : if (tlistl == list_head(input_tlists))
1651 : 11840 : colTypmods[colindex] = subtypmod;
1652 [ + + ]: 22432 : else if (subtypmod != colTypmods[colindex])
1653 : 10 : colTypmods[colindex] = -1;
1654 : : }
1655 : : else
1656 : : {
1657 : : /* types disagree, so force typmod to -1 */
1658 : 0 : colTypmods[colindex] = -1;
1659 : : }
1660 : 34272 : curColType = lnext(colTypes, curColType);
1661 : 34272 : colindex++;
1662 : : }
1663 : : Assert(curColType == NULL);
1664 : : }
1665 : :
1666 : : /*
1667 : : * Now we can build the tlist for the Append.
1668 : : */
1669 : 4356 : colindex = 0;
1670 [ + + + + : 16196 : forthree(curColType, colTypes, curColCollation, colCollations,
+ + + + +
+ + + + +
+ - + - +
+ ]
1671 : : ref_tl_item, refnames_tlist)
1672 : : {
1673 : 11840 : Oid colType = lfirst_oid(curColType);
1674 : 11840 : int32 colTypmod = colTypmods[colindex++];
1675 : 11840 : Oid colColl = lfirst_oid(curColCollation);
1676 : 11840 : TargetEntry *reftle = (TargetEntry *) lfirst(ref_tl_item);
1677 : :
1678 : : Assert(reftle->resno == resno);
1679 : : Assert(!reftle->resjunk);
1680 : 11840 : expr = (Node *) makeVar(0,
1681 : : resno,
1682 : : colType,
1683 : : colTypmod,
1684 : : colColl,
1685 : : 0);
1686 : 23680 : tle = makeTargetEntry((Expr *) expr,
1687 : 11840 : (AttrNumber) resno++,
1688 : 11840 : pstrdup(reftle->resname),
1689 : : false);
1690 : :
1691 : : /*
1692 : : * By convention, all output columns in a setop tree have
1693 : : * ressortgroupref equal to their resno. In some cases the ref isn't
1694 : : * needed, but this is a cleaner way than modifying the tlist later.
1695 : : */
1696 : 11840 : tle->ressortgroupref = tle->resno;
1697 : :
1698 : 11840 : tlist = lappend(tlist, tle);
1699 : : }
1700 : :
1701 : 4356 : pfree(colTypmods);
1702 : :
1703 : 4356 : return tlist;
1704 : : }
1705 : :
1706 : : /*
1707 : : * generate_setop_grouplist
1708 : : * Build a SortGroupClause list defining the sort/grouping properties
1709 : : * of the setop's output columns.
1710 : : *
1711 : : * Parse analysis already determined the properties and built a suitable
1712 : : * list, except that the entries do not have sortgrouprefs set because
1713 : : * the parser output representation doesn't include a tlist for each
1714 : : * setop. So what we need to do here is copy that list and install
1715 : : * proper sortgrouprefs into it (copying those from the targetlist).
1716 : : */
1717 : : static List *
1718 : 4118 : generate_setop_grouplist(SetOperationStmt *op, List *targetlist)
1719 : : {
1720 : 4118 : List *grouplist = copyObject(op->groupClauses);
1721 : : ListCell *lg;
1722 : : ListCell *lt;
1723 : :
1724 : 4118 : lg = list_head(grouplist);
1725 [ + + + + : 15825 : foreach(lt, targetlist)
+ + ]
1726 : : {
1727 : 11707 : TargetEntry *tle = (TargetEntry *) lfirst(lt);
1728 : : SortGroupClause *sgc;
1729 : :
1730 : : Assert(!tle->resjunk);
1731 : :
1732 : : /* non-resjunk columns should have sortgroupref = resno */
1733 : : Assert(tle->ressortgroupref == tle->resno);
1734 : :
1735 : : /* non-resjunk columns should have grouping clauses */
1736 : : Assert(lg != NULL);
1737 : 11707 : sgc = (SortGroupClause *) lfirst(lg);
1738 : 11707 : lg = lnext(grouplist, lg);
1739 : : Assert(sgc->tleSortGroupRef == 0);
1740 : :
1741 : 11707 : sgc->tleSortGroupRef = tle->ressortgroupref;
1742 : : }
1743 : : Assert(lg == NULL);
1744 : 4118 : return grouplist;
1745 : : }
1746 : :
1747 : : /*
1748 : : * create_setop_pathtarget
1749 : : * Do the normal create_pathtarget() work, plus set the resulting
1750 : : * PathTarget's width to the average width of the Paths in child_pathlist
1751 : : * weighted using the estimated row count of each path.
1752 : : *
1753 : : * Note: This is required because set op target lists use varno==0, which
1754 : : * results in a type default width estimate rather than one that's based on
1755 : : * statistics of the columns from the set op children.
1756 : : */
1757 : : static PathTarget *
1758 : 4343 : create_setop_pathtarget(PlannerInfo *root, List *tlist, List *child_pathlist)
1759 : : {
1760 : : PathTarget *reltarget;
1761 : : ListCell *lc;
1762 : 4343 : double parent_rows = 0;
1763 : 4343 : double parent_size = 0;
1764 : :
1765 : 4343 : reltarget = create_pathtarget(root, tlist);
1766 : :
1767 : : /* Calculate the total rows and total size. */
1768 [ + + + + : 15714 : foreach(lc, child_pathlist)
+ + ]
1769 : : {
1770 : 11371 : Path *path = (Path *) lfirst(lc);
1771 : :
1772 : 11371 : parent_rows += path->rows;
1773 : 11371 : parent_size += path->parent->reltarget->width * path->rows;
1774 : : }
1775 : :
1776 [ + + ]: 4343 : if (parent_rows > 0)
1777 : 4328 : reltarget->width = rint(parent_size / parent_rows);
1778 : :
1779 : 4343 : return reltarget;
1780 : : }
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