Age Owner Branch data TLA Line data Source code
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 *
3711 tgl@sss.pgh.pa.us 98 :CBC 4974 : plan_set_operations(PlannerInfo *root)
99 : : {
7639 100 : 4974 : Query *parse = root->parse;
3360 peter_e@gmx.net 101 : 4974 : 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 [ - + ]: 4974 : Assert(topop);
109 : :
110 : : /* check for unsupported stuff */
8329 tgl@sss.pgh.pa.us 111 [ - + ]: 4974 : Assert(parse->jointree->fromlist == NIL);
112 [ - + ]: 4974 : Assert(parse->jointree->quals == NULL);
113 [ - + ]: 4974 : Assert(parse->groupClause == NIL);
114 [ - + ]: 4974 : Assert(parse->havingQual == NULL);
6337 115 [ - + ]: 4974 : Assert(parse->windowClause == NIL);
8329 116 [ - + ]: 4974 : 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 : : */
2480 drowley@postgresql.o 124 [ - + ]: 4974 : Assert(root->eq_classes == NIL);
125 : 4974 : 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 : : */
5358 tgl@sss.pgh.pa.us 132 : 4974 : 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 : : */
9343 138 : 4974 : node = topop->larg;
139 [ + - + + ]: 8343 : while (node && IsA(node, SetOperationStmt))
140 : 3369 : node = ((SetOperationStmt *) node)->larg;
141 [ + - - + ]: 4974 : Assert(node && IsA(node, RangeTblRef));
5358 142 : 4974 : leftmostRTE = root->simple_rte_array[((RangeTblRef *) node)->rtindex];
143 : 4974 : leftmostQuery = leftmostRTE->subquery;
9343 144 [ - + ]: 4974 : Assert(leftmostQuery != NULL);
145 : :
146 : : /*
147 : : * If the topmost node is a recursive union, it needs special processing.
148 : : */
6422 149 [ + + ]: 4974 : if (root->hasRecursion)
150 : : {
2969 rhaas@postgresql.org 151 : 694 : 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 : 4280 : 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. */
3711 tgl@sss.pgh.pa.us 173 : 4970 : root->processed_tlist = top_tlist;
174 : :
175 : 4970 : 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 *
7639 214 : 17802 : 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 : :
714 rhaas@postgresql.org 223 : 17802 : *istrivial_tlist = true; /* for now */
224 : :
225 : : /* Guard against stack overflow due to overly complex setop nests */
3019 tgl@sss.pgh.pa.us 226 : 17802 : check_stack_depth();
227 : :
9343 228 [ + + ]: 17802 : if (IsA(setOp, RangeTblRef))
229 : : {
230 : 13377 : RangeTblRef *rtr = (RangeTblRef *) setOp;
5358 231 : 13377 : RangeTblEntry *rte = root->simple_rte_array[rtr->rtindex];
9175 bruce@momjian.us 232 : 13377 : Query *subquery = rte->subquery;
233 : : PlannerInfo *subroot;
234 : : List *tlist;
235 : : bool trivial_tlist;
236 : : char *plan_name;
237 : :
9343 tgl@sss.pgh.pa.us 238 [ - + ]: 13377 : Assert(subquery != NULL);
239 : :
240 : : /* Build a RelOptInfo for this leaf subquery. */
3319 rhaas@postgresql.org 241 : 13377 : rel = build_simple_rel(root, rtr->rtindex, NULL);
242 : :
243 : : /* plan_params should not be in use in current query level */
4990 tgl@sss.pgh.pa.us 244 [ - + ]: 13377 : 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 : : */
210 rhaas@postgresql.org 251 :GNC 13377 : plan_name = choose_plan_name(root->glob, "setop", true);
252 : 13377 : 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 : : */
4990 tgl@sss.pgh.pa.us 261 [ - + ]:CBC 13377 : if (root->plan_params)
4990 tgl@sss.pgh.pa.us 262 [ # # ]:UBC 0 : elog(ERROR, "unexpected outer reference in set operation subquery");
263 : :
264 : : /* Figure out the appropriate target list for this subquery. */
2969 rhaas@postgresql.org 265 :CBC 13377 : tlist = generate_setop_tlist(colTypes, colCollations,
266 : 13377 : rtr->rtindex,
267 : : true,
268 : : subroot->processed_tlist,
269 : : refnames_tlist,
270 : : &trivial_tlist);
271 : 13377 : rel->reltarget = create_pathtarget(root, tlist);
272 : :
273 : : /* Return the fully-fledged tlist to caller, too */
274 : 13377 : *pTargetList = tlist;
714 275 : 13377 : *istrivial_tlist = trivial_tlist;
276 : : }
9343 tgl@sss.pgh.pa.us 277 [ + - ]: 4425 : else if (IsA(setOp, SetOperationStmt))
278 : : {
279 : 4425 : SetOperationStmt *op = (SetOperationStmt *) setOp;
280 : :
281 : : /* UNIONs are much different from INTERSECT/EXCEPT */
282 [ + + ]: 4425 : if (op->op == SETOP_UNION)
2969 rhaas@postgresql.org 283 : 3801 : 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 : : */
502 tgl@sss.pgh.pa.us 304 [ + + ]: 4425 : if (!tlist_same_datatypes(*pTargetList, colTypes, false) ||
305 [ - + ]: 4410 : !tlist_same_collations(*pTargetList, colCollations, false))
306 : : {
307 : : PathTarget *target;
308 : : bool trivial_tlist;
309 : : ListCell *lc;
310 : :
3711 311 : 15 : *pTargetList = generate_setop_tlist(colTypes, colCollations,
312 : : 0,
313 : : false,
314 : : *pTargetList,
315 : : refnames_tlist,
316 : : &trivial_tlist);
714 rhaas@postgresql.org 317 : 15 : *istrivial_tlist = trivial_tlist;
2969 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 [ - + ]: 15 : 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 : : {
2969 rhaas@postgresql.org 337 :UBC 0 : Path *subpath = (Path *) lfirst(lc);
338 : : Path *path;
339 : :
340 [ # # ]: 0 : 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 : : }
714 rhaas@postgresql.org 348 :CBC 4425 : postprocess_setop_rel(root, rel);
349 : : }
350 : : else
351 : : {
8320 tgl@sss.pgh.pa.us 352 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
353 : : (int) nodeTag(setOp));
354 : : *pTargetList = NIL;
355 : : rel = NULL; /* keep compiler quiet */
356 : : }
357 : :
2969 rhaas@postgresql.org 358 :CBC 17802 : return rel;
359 : : }
360 : :
361 : : /*
362 : : * Generate paths for a recursive UNION node
363 : : */
364 : : static RelOptInfo *
3711 tgl@sss.pgh.pa.us 365 : 694 : 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 */
6419 384 [ - + ]: 694 : if (setOp->op != SETOP_UNION)
6419 tgl@sss.pgh.pa.us 385 [ # # ]:UBC 0 : elog(ERROR, "only UNION queries can be recursive");
386 : : /* Worktable ID should be assigned */
6422 tgl@sss.pgh.pa.us 387 [ - + ]:CBC 694 : 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 : : */
2969 rhaas@postgresql.org 393 : 694 : 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);
714 399 [ + - ]: 694 : if (lrel->rtekind == RTE_SUBQUERY)
400 : 694 : build_setop_child_paths(root, lrel, lpath_trivial_tlist, lpath_tlist,
401 : : NIL, NULL);
2969 402 : 694 : lpath = lrel->cheapest_total_path;
403 : : /* The right path will want to look at the left one ... */
3711 tgl@sss.pgh.pa.us 404 : 694 : root->non_recursive_path = lpath;
2969 rhaas@postgresql.org 405 : 694 : 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);
714 411 [ + + ]: 694 : if (rrel->rtekind == RTE_SUBQUERY)
412 : 689 : build_setop_child_paths(root, rrel, rpath_trivial_tlist, rpath_tlist,
413 : : NIL, NULL);
2969 414 : 694 : rpath = rrel->cheapest_total_path;
3711 tgl@sss.pgh.pa.us 415 : 694 : root->non_recursive_path = NULL;
416 : :
417 : : /*
418 : : * Generate tlist for RecursiveUnion path node --- same as in Append cases
419 : : */
502 420 : 694 : tlist = generate_append_tlist(setOp->colTypes, setOp->colCollations,
3711 tgl@sss.pgh.pa.us 421 :ECB (455) : list_make2(lpath_tlist, rpath_tlist),
422 : : refnames_tlist);
423 : :
3711 tgl@sss.pgh.pa.us 424 :CBC 694 : *pTargetList = tlist;
425 : :
426 : : /* Build result relation. */
2969 rhaas@postgresql.org 427 : 694 : result_rel = fetch_upper_rel(root, UPPERREL_SETOP,
428 : 694 : bms_union(lrel->relids, rrel->relids));
429 : 694 : result_rel->reltarget = create_pathtarget(root, tlist);
430 : :
431 : : /*
432 : : * If UNION, identify the grouping operators
433 : : */
6419 tgl@sss.pgh.pa.us 434 [ + + ]: 694 : if (setOp->all)
435 : : {
436 : 402 : groupList = NIL;
3711 437 : 402 : dNumGroups = 0;
438 : : }
439 : : else
440 : : {
441 : : /* Identify the grouping semantics */
6419 442 : 292 : groupList = generate_setop_grouplist(setOp, tlist);
443 : :
444 : : /* We only support hashing here */
445 [ + + ]: 292 : 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 : : */
3711 455 : 288 : dNumGroups = lpath->rows + rpath->rows * 10;
456 : : }
457 : :
458 : : /*
459 : : * And make the path node.
460 : : */
461 : 690 : path = (Path *) create_recursiveunion_path(root,
462 : : result_rel,
463 : : lpath,
464 : : rpath,
2969 rhaas@postgresql.org 465 : 690 : result_rel->reltarget,
466 : : groupList,
467 : : root->wt_param_id,
468 : : dNumGroups);
469 : :
470 : 690 : add_path(result_rel, path);
471 : 690 : postprocess_setop_rel(root, result_rel);
472 : 690 : 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
714 489 : 13377 : 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 : 13377 : 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 [ - + ]: 13377 : Assert(rel->rtekind == RTE_SUBQUERY);
499 : :
500 : : /* when sorting is needed, add child rel equivalences */
501 [ + + ]: 13377 : if (interesting_pathkeys != NIL)
502 : 10198 : 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 : 13377 : 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 : 13377 : final_rel = fetch_upper_rel(rel->subroot, UPPERREL_FINAL, NULL);
519 : 13377 : rel->consider_parallel = final_rel->consider_parallel;
520 : :
521 : : /* Generate subquery scan paths for any interesting path in final_rel */
522 [ + - + + : 34799 : foreach(lc, final_rel->pathlist)
+ + ]
523 : : {
524 : 21422 : Path *subpath = (Path *) lfirst(lc);
525 : : List *pathkeys;
526 : 21422 : 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 */
213 drowley@postgresql.o 531 [ + + ]:GNC 21422 : if (is_dummy_rel(final_rel))
532 : : {
533 : 72 : mark_dummy_rel(rel);
534 : 3275 : 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 : : */
714 rhaas@postgresql.org 542 [ + + ]:CBC 21350 : if (subpath == cheapest_input_path)
543 : : {
544 : : /* Convert subpath's pathkeys to outer representation */
545 : 13305 : pathkeys = convert_subquery_pathkeys(root, rel, subpath->pathkeys,
546 : : make_tlist_from_pathtarget(subpath->pathtarget));
547 : :
548 : : /* Generate outer path using this subpath */
549 : 13305 : 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 [ + + ]: 21350 : if (interesting_pathkeys == NIL)
559 : 3193 : 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 : 18157 : is_sorted = pathkeys_count_contained_in(setop_pathkeys,
567 : : subpath->pathkeys,
568 : : &presorted_keys);
569 : :
570 [ + + ]: 18157 : if (!is_sorted)
571 : : {
572 : 12044 : 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 [ + + ]: 12044 : 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 [ + + + + ]: 12034 : if (presorted_keys == 0 || !enable_incremental_sort)
591 : 9368 : 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 [ + + ]: 18147 : if (subpath != cheapest_input_path)
611 : : {
612 : : /* Convert subpath's pathkeys to outer representation */
613 : 17377 : pathkeys = convert_subquery_pathkeys(root, rel, subpath->pathkeys,
614 : : make_tlist_from_pathtarget(subpath->pathtarget));
615 : :
616 : : /* Generate outer path using this subpath */
617 : 17377 : 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 [ + + - + ]: 13377 : 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 [ + + + - ]: 13377 : if (rel->consider_parallel && bms_is_empty(rel->lateral_relids) &&
636 [ + + ]: 9324 : 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 : 13377 : 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 [ + + ]: 13377 : if (pNumGroups)
670 : : {
671 : 1218 : PlannerInfo *subroot = rel->subroot;
672 : 1218 : Query *subquery = subroot->parse;
673 : :
674 [ + - + - ]: 1218 : if (subquery->groupClause || subquery->groupingSets ||
675 [ + + + - ]: 1218 : subquery->distinctClause || subroot->hasHavingQual ||
676 [ - + ]: 1208 : subquery->hasAggs)
677 : 10 : *pNumGroups = rel->cheapest_total_path->rows;
678 : : else
679 : 1208 : *pNumGroups = estimate_num_groups(subroot,
446 akorotkov@postgresql 680 : 1208 : get_tlist_exprs(subroot->parse->targetList, false),
714 rhaas@postgresql.org 681 : 1208 : rel->cheapest_total_path->rows,
682 : : NULL,
683 : : NULL);
684 : : }
685 : 13377 : }
686 : :
687 : : /*
688 : : * Generate paths for a UNION or UNION ALL node
689 : : */
690 : : static RelOptInfo *
2969 691 : 3801 : generate_union_paths(SetOperationStmt *op, PlannerInfo *root,
692 : : List *refnames_tlist,
693 : : List **pTargetList)
694 : : {
695 : 3801 : Relids relids = NULL;
696 : : RelOptInfo *result_rel;
697 : : ListCell *lc;
698 : : ListCell *lc2;
699 : : ListCell *lc3;
84 rhaas@postgresql.org 700 :GNC 3801 : AppendPathInput cheapest = {0};
701 : 3801 : AppendPathInput ordered = {0};
702 : 3801 : AppendPathInput partial = {0};
2966 rhaas@postgresql.org 703 :CBC 3801 : bool partial_paths_valid = true;
704 : 3801 : bool consider_parallel = true;
705 : : List *rellist;
706 : : List *tlist_list;
707 : : List *trivial_tlist_list;
708 : : List *tlist;
714 709 : 3801 : List *groupList = NIL;
710 : : Path *apath;
711 : 3801 : Path *gpath = NULL;
712 : 3801 : bool try_sorted = false;
713 : 3801 : List *union_pathkeys = NIL;
714 : :
715 : : /*
716 : : * If any of my children are identical UNION nodes (same op, all-flag, and
717 : : * colTypes/colCollations) then they can be merged into this node so that
718 : : * we generate only one Append/MergeAppend and unique-ification for the
719 : : * lot. Recurse to find such nodes.
720 : : */
721 : 3801 : rellist = plan_union_children(root,
722 : : op,
723 : : refnames_tlist,
724 : : &tlist_list,
725 : : &trivial_tlist_list);
726 : :
727 : : /*
728 : : * Generate tlist for Append/MergeAppend plan node.
729 : : *
730 : : * The tlist for an Append plan isn't important as far as the Append is
731 : : * concerned, but we must make it look real anyway for the benefit of the
732 : : * next plan level up.
733 : : */
502 tgl@sss.pgh.pa.us 734 : 3801 : tlist = generate_append_tlist(op->colTypes, op->colCollations,
735 : : tlist_list, refnames_tlist);
715 736 : 3801 : *pTargetList = tlist;
737 : :
738 : : /* For UNIONs (not UNION ALL), try sorting, if sorting is possible */
714 rhaas@postgresql.org 739 [ + + ]: 3801 : if (!op->all)
740 : : {
741 : : /* Identify the grouping semantics */
742 : 3269 : groupList = generate_setop_grouplist(op, tlist);
743 : :
744 [ + + ]: 3269 : if (grouping_is_sortable(op->groupClauses))
745 : : {
746 : 3209 : try_sorted = true;
747 : : /* Determine the pathkeys for sorting by the whole target list */
748 : 3209 : union_pathkeys = make_pathkeys_for_sortclauses(root, groupList,
749 : : tlist);
750 : :
751 : 3209 : root->query_pathkeys = union_pathkeys;
752 : : }
753 : : }
754 : :
755 : : /*
756 : : * Now that we've got the append target list, we can build the union child
757 : : * paths.
758 : : */
759 [ + - + + : 14687 : forthree(lc, rellist, lc2, trivial_tlist_list, lc3, tlist_list)
+ - + + +
- + + + +
+ - + - +
+ ]
760 : : {
761 : 10886 : RelOptInfo *rel = lfirst(lc);
762 : 10886 : bool trivial_tlist = lfirst_int(lc2);
763 : 10886 : List *child_tlist = lfirst_node(List, lc3);
764 : :
765 : : /* only build paths for the union children */
766 [ + + ]: 10886 : if (rel->rtekind == RTE_SUBQUERY)
767 : 10776 : build_setop_child_paths(root, rel, trivial_tlist, child_tlist,
768 : : union_pathkeys, NULL);
769 : : }
770 : :
771 : : /* Build path lists and relid set. */
2969 772 [ + - + + : 14687 : foreach(lc, rellist)
+ + ]
773 : : {
774 : 10886 : RelOptInfo *rel = lfirst(lc);
775 : : Path *ordered_path;
776 : :
777 : : /*
778 : : * Record the relids so that we can identify the correct
779 : : * UPPERREL_SETOP RelOptInfo below.
780 : : */
181 drowley@postgresql.o 781 :GNC 10886 : relids = bms_add_members(relids, rel->relids);
782 : :
783 : : /* Skip any UNION children that are proven not to yield any rows */
213 784 [ + + ]: 10886 : if (is_dummy_rel(rel))
785 : 42 : continue;
786 : :
84 rhaas@postgresql.org 787 : 21688 : cheapest.subpaths = lappend(cheapest.subpaths,
714 rhaas@postgresql.org 788 :CBC 10844 : rel->cheapest_total_path);
789 : :
790 [ + + ]: 10844 : if (try_sorted)
791 : : {
792 : 3466 : ordered_path = get_cheapest_path_for_pathkeys(rel->pathlist,
793 : : union_pathkeys,
794 : : NULL,
795 : : TOTAL_COST,
796 : : false);
797 : :
798 [ + + ]: 3466 : if (ordered_path != NULL)
84 rhaas@postgresql.org 799 :GNC 509 : ordered.subpaths = lappend(ordered.subpaths, ordered_path);
800 : : else
801 : : {
802 : : /*
803 : : * If we can't find a sorted path, just give up trying to
804 : : * generate a list of correctly sorted child paths. This can
805 : : * happen when type coercion was added to the targetlist due
806 : : * to mismatching types from the union children.
807 : : */
714 rhaas@postgresql.org 808 :CBC 2957 : try_sorted = false;
809 : : }
810 : : }
811 : :
2966 812 [ + + ]: 10844 : if (consider_parallel)
813 : : {
814 [ + + ]: 7904 : if (!rel->consider_parallel)
815 : : {
816 : 2825 : consider_parallel = false;
817 : 2825 : partial_paths_valid = false;
818 : : }
819 [ + + ]: 5079 : else if (rel->partial_pathlist == NIL)
820 : 5069 : partial_paths_valid = false;
821 : : else
84 rhaas@postgresql.org 822 :GNC 10 : partial.partial_subpaths = lappend(partial.partial_subpaths,
823 : 10 : linitial(rel->partial_pathlist));
824 : : }
825 : : }
826 : :
827 : : /* Build result relation. */
2969 rhaas@postgresql.org 828 :CBC 3801 : result_rel = fetch_upper_rel(root, UPPERREL_SETOP, relids);
218 drowley@postgresql.o 829 :GNC 3801 : result_rel->reltarget = create_setop_pathtarget(root, tlist,
830 : : cheapest.subpaths);
2966 rhaas@postgresql.org 831 :CBC 3801 : result_rel->consider_parallel = consider_parallel;
714 832 : 3801 : result_rel->consider_startup = (root->tuple_fraction > 0);
833 : :
834 : : /* If all UNION children were dummy rels, make the resulting rel dummy */
84 rhaas@postgresql.org 835 [ + + ]:GNC 3801 : if (cheapest.subpaths == NIL)
836 : : {
213 drowley@postgresql.o 837 : 5 : mark_dummy_rel(result_rel);
838 : :
839 : 5 : return result_rel;
840 : : }
841 : :
842 : : /*
843 : : * Append the child results together using the cheapest paths from each
844 : : * union child.
845 : : */
84 rhaas@postgresql.org 846 : 3796 : apath = (Path *) create_append_path(root, result_rel, cheapest,
847 : : NIL, NULL, 0, false, -1);
848 : :
849 : : /*
850 : : * Estimate number of groups. For now we just assume the output is unique
851 : : * --- this is certainly true for the UNION case, and we want worst-case
852 : : * estimates anyway.
853 : : */
714 rhaas@postgresql.org 854 :CBC 3796 : result_rel->rows = apath->rows;
855 : :
856 : : /*
857 : : * Now consider doing the same thing using the partial paths plus Append
858 : : * plus Gather.
859 : : */
2966 860 [ + + ]: 3796 : if (partial_paths_valid)
861 : : {
862 : : Path *papath;
863 : 5 : int parallel_workers = 0;
864 : :
865 : : /* Find the highest number of workers requested for any subpath. */
84 rhaas@postgresql.org 866 [ + - + + :GNC 15 : foreach(lc, partial.partial_subpaths)
+ + ]
867 : : {
1308 drowley@postgresql.o 868 :CBC 10 : Path *subpath = lfirst(lc);
869 : :
870 : 10 : parallel_workers = Max(parallel_workers,
871 : : subpath->parallel_workers);
872 : : }
2966 rhaas@postgresql.org 873 [ - + ]: 5 : Assert(parallel_workers > 0);
874 : :
875 : : /*
876 : : * If the use of parallel append is permitted, always request at least
877 : : * log2(# of children) paths. We assume it can be useful to have
878 : : * extra workers in this case because they will be spread out across
879 : : * the children. The precise formula is just a guess; see
880 : : * add_paths_to_append_rel.
881 : : */
882 [ + - ]: 5 : if (enable_parallel_append)
883 : : {
884 [ + - ]: 5 : parallel_workers = Max(parallel_workers,
885 : : pg_leftmost_one_pos32(list_length(partial.partial_subpaths)) + 1);
886 : 5 : parallel_workers = Min(parallel_workers,
887 : : max_parallel_workers_per_gather);
888 : : }
889 [ - + ]: 5 : Assert(parallel_workers > 0);
890 : :
891 : : papath = (Path *)
84 rhaas@postgresql.org 892 :GNC 5 : create_append_path(root, result_rel, partial,
893 : : NIL, NULL, parallel_workers,
894 : : enable_parallel_append, -1);
895 : : gpath = (Path *)
714 rhaas@postgresql.org 896 :CBC 5 : create_gather_path(root, result_rel, papath,
2966 897 : 5 : result_rel->reltarget, NULL, NULL);
898 : : }
899 : :
714 900 [ + + ]: 3796 : if (!op->all)
901 : : {
902 : : double dNumGroups;
903 : 3264 : bool can_sort = grouping_is_sortable(groupList);
904 : 3264 : bool can_hash = grouping_is_hashable(groupList);
84 rhaas@postgresql.org 905 :GNC 3264 : Path *first_path = linitial(cheapest.subpaths);
906 : :
907 : : /*
908 : : * Estimate the number of UNION output rows. In the case when only a
909 : : * single UNION child remains, we can use estimate_num_groups() on
910 : : * that child. We must be careful not to do this when that child is
911 : : * the result of some other set operation as the targetlist will
912 : : * contain Vars with varno==0, which estimate_num_groups() wouldn't
913 : : * like.
914 : : */
915 [ + + ]: 3264 : if (list_length(cheapest.subpaths) == 1 &&
180 drowley@postgresql.o 916 [ + + ]: 15 : first_path->parent->reloptkind != RELOPT_UPPER_REL)
917 : : {
213 918 : 10 : dNumGroups = estimate_num_groups(root,
180 919 : 10 : first_path->pathtarget->exprs,
920 : : first_path->rows,
921 : : NULL,
922 : : NULL);
923 : : }
924 : : else
925 : : {
926 : : /*
927 : : * Otherwise, for the moment, take the number of distinct groups
928 : : * as equal to the total input size, i.e., the worst case. This
929 : : * is too conservative, but it's not clear how to get a decent
930 : : * estimate of the true size. One should note as well the
931 : : * propensity of novices to write UNION rather than UNION ALL even
932 : : * when they don't expect any duplicates...
933 : : */
213 934 : 3254 : dNumGroups = apath->rows;
935 : : }
936 : :
714 rhaas@postgresql.org 937 [ + + ]:CBC 3264 : if (can_hash)
938 : : {
939 : : Path *path;
940 : :
941 : : /*
942 : : * Try a hash aggregate plan on 'apath'. This is the cheapest
943 : : * available path containing each append child.
944 : : */
945 : 3204 : path = (Path *) create_agg_path(root,
946 : : result_rel,
947 : : apath,
218 drowley@postgresql.o 948 :GNC 3204 : result_rel->reltarget,
949 : : AGG_HASHED,
950 : : AGGSPLIT_SIMPLE,
951 : : groupList,
952 : : NIL,
953 : : NULL,
954 : : dNumGroups);
714 rhaas@postgresql.org 955 :CBC 3204 : add_path(result_rel, path);
956 : :
957 : : /* Try hash aggregate on the Gather path, if valid */
958 [ + + ]: 3204 : if (gpath != NULL)
959 : : {
960 : : /* Hashed aggregate plan --- no sort needed */
961 : 5 : path = (Path *) create_agg_path(root,
962 : : result_rel,
963 : : gpath,
218 drowley@postgresql.o 964 :GNC 5 : result_rel->reltarget,
965 : : AGG_HASHED,
966 : : AGGSPLIT_SIMPLE,
967 : : groupList,
968 : : NIL,
969 : : NULL,
970 : : dNumGroups);
714 rhaas@postgresql.org 971 :CBC 5 : add_path(result_rel, path);
972 : : }
973 : : }
974 : :
975 [ + + ]: 3264 : if (can_sort)
976 : : {
977 : 3204 : Path *path = apath;
978 : :
979 : : /* Try Sort -> Unique on the Append path */
980 [ + + ]: 3204 : if (groupList != NIL)
981 : 3179 : path = (Path *) create_sort_path(root, result_rel, path,
982 : : make_pathkeys_for_sortclauses(root, groupList, tlist),
983 : : -1.0);
984 : :
259 rguo@postgresql.org 985 :GNC 3204 : path = (Path *) create_unique_path(root,
986 : : result_rel,
987 : : path,
988 : 3204 : list_length(path->pathkeys),
989 : : dNumGroups);
990 : :
714 rhaas@postgresql.org 991 :CBC 3204 : add_path(result_rel, path);
992 : :
993 : : /* Try Sort -> Unique on the Gather path, if set */
994 [ + + ]: 3204 : if (gpath != NULL)
995 : : {
996 : 5 : path = gpath;
997 : :
998 : 5 : path = (Path *) create_sort_path(root, result_rel, path,
999 : : make_pathkeys_for_sortclauses(root, groupList, tlist),
1000 : : -1.0);
1001 : :
259 rguo@postgresql.org 1002 :GNC 5 : path = (Path *) create_unique_path(root,
1003 : : result_rel,
1004 : : path,
1005 : 5 : list_length(path->pathkeys),
1006 : : dNumGroups);
714 rhaas@postgresql.org 1007 :CBC 5 : add_path(result_rel, path);
1008 : : }
1009 : : }
1010 : :
1011 : : /*
1012 : : * Try making a MergeAppend path if we managed to find a path with the
1013 : : * correct pathkeys in each union child query.
1014 : : */
1015 [ + + + + ]: 3264 : if (try_sorted && groupList != NIL)
1016 : : {
1017 : : Path *path;
1018 : :
1019 : 222 : path = (Path *) create_merge_append_path(root,
1020 : : result_rel,
1021 : : ordered.subpaths,
1022 : : NIL,
1023 : : union_pathkeys,
1024 : : NULL);
1025 : :
1026 : : /* and make the MergeAppend unique */
259 rguo@postgresql.org 1027 :GNC 222 : path = (Path *) create_unique_path(root,
1028 : : result_rel,
1029 : : path,
1030 : : list_length(tlist),
1031 : : dNumGroups);
1032 : :
714 rhaas@postgresql.org 1033 :CBC 222 : add_path(result_rel, path);
1034 : : }
1035 : : }
1036 : : else
1037 : : {
1038 : : /* UNION ALL */
1039 : 532 : add_path(result_rel, apath);
1040 : :
1041 [ - + ]: 532 : if (gpath != NULL)
714 rhaas@postgresql.org 1042 :UBC 0 : add_path(result_rel, gpath);
1043 : : }
1044 : :
2969 rhaas@postgresql.org 1045 :CBC 3796 : return result_rel;
1046 : : }
1047 : :
1048 : : /*
1049 : : * Generate paths for an INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL node
1050 : : */
1051 : : static RelOptInfo *
1052 : 624 : generate_nonunion_paths(SetOperationStmt *op, PlannerInfo *root,
1053 : : List *refnames_tlist,
1054 : : List **pTargetList)
1055 : : {
1056 : : RelOptInfo *result_rel;
1057 : : RelOptInfo *lrel,
1058 : : *rrel;
3711 tgl@sss.pgh.pa.us 1059 : 624 : double save_fraction = root->tuple_fraction;
1060 : : Path *lpath,
1061 : : *rpath,
1062 : : *path;
1063 : : List *lpath_tlist,
1064 : : *rpath_tlist,
1065 : : *tlist,
1066 : : *groupList;
1067 : : bool lpath_trivial_tlist,
1068 : : rpath_trivial_tlist,
1069 : : result_trivial_tlist;
502 1070 : 624 : List *nonunion_pathkeys = NIL;
1071 : : double dLeftGroups,
1072 : : dRightGroups,
1073 : : dNumGroups,
1074 : : dNumOutputRows;
1075 : : bool can_sort;
1076 : : bool can_hash;
1077 : : SetOpCmd cmd;
1078 : :
1079 : : /*
1080 : : * Tell children to fetch all tuples.
1081 : : */
3711 1082 : 624 : root->tuple_fraction = 0.0;
1083 : :
1084 : : /* Recurse on children */
2969 rhaas@postgresql.org 1085 : 624 : lrel = recurse_set_operations(op->larg, root,
1086 : : op,
1087 : : op->colTypes, op->colCollations,
1088 : : refnames_tlist,
1089 : : &lpath_tlist,
1090 : : &lpath_trivial_tlist);
1091 : :
1092 : 624 : rrel = recurse_set_operations(op->rarg, root,
1093 : : op,
1094 : : op->colTypes, op->colCollations,
1095 : : refnames_tlist,
1096 : : &rpath_tlist,
1097 : : &rpath_trivial_tlist);
1098 : :
1099 : : /*
1100 : : * Generate tlist for SetOp plan node.
1101 : : *
1102 : : * The tlist for a SetOp plan isn't important so far as the SetOp is
1103 : : * concerned, but we must make it look real anyway for the benefit of the
1104 : : * next plan level up.
1105 : : */
502 tgl@sss.pgh.pa.us 1106 : 624 : tlist = generate_setop_tlist(op->colTypes, op->colCollations,
1107 : : 0, false, lpath_tlist, refnames_tlist,
1108 : : &result_trivial_tlist);
1109 : :
1110 : : /* We should not have needed any type coercions in the tlist */
1111 [ - + ]: 624 : Assert(result_trivial_tlist);
1112 : :
1113 : 624 : *pTargetList = tlist;
1114 : :
1115 : : /* Identify the grouping semantics */
1116 : 624 : groupList = generate_setop_grouplist(op, tlist);
1117 : :
1118 : : /* Check whether the operators support sorting or hashing */
1119 : 624 : can_sort = grouping_is_sortable(groupList);
1120 : 624 : can_hash = grouping_is_hashable(groupList);
1121 [ - + - - ]: 624 : if (!can_sort && !can_hash)
502 tgl@sss.pgh.pa.us 1122 [ # # # # ]:UBC 0 : ereport(ERROR,
1123 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1124 : : /* translator: %s is INTERSECT or EXCEPT */
1125 : : errmsg("could not implement %s",
1126 : : (op->op == SETOP_INTERSECT) ? "INTERSECT" : "EXCEPT"),
1127 : : errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
1128 : :
502 tgl@sss.pgh.pa.us 1129 [ + - ]:CBC 624 : if (can_sort)
1130 : : {
1131 : : /* Determine the pathkeys for sorting by the whole target list */
1132 : 624 : nonunion_pathkeys = make_pathkeys_for_sortclauses(root, groupList,
1133 : : tlist);
1134 : :
1135 : 624 : root->query_pathkeys = nonunion_pathkeys;
1136 : : }
1137 : :
1138 : : /*
1139 : : * Now that we've got all that info, we can build the child paths.
1140 : : */
1141 [ + + ]: 624 : if (lrel->rtekind == RTE_SUBQUERY)
1142 : 604 : build_setop_child_paths(root, lrel, lpath_trivial_tlist, lpath_tlist,
1143 : : nonunion_pathkeys, &dLeftGroups);
1144 : : else
1145 : 20 : dLeftGroups = lrel->rows;
714 rhaas@postgresql.org 1146 [ + + ]: 624 : if (rrel->rtekind == RTE_SUBQUERY)
1147 : 614 : build_setop_child_paths(root, rrel, rpath_trivial_tlist, rpath_tlist,
1148 : : nonunion_pathkeys, &dRightGroups);
1149 : : else
1150 : 10 : dRightGroups = rrel->rows;
1151 : :
1152 : : /* Undo effects of forcing tuple_fraction to 0 */
3711 tgl@sss.pgh.pa.us 1153 : 624 : root->tuple_fraction = save_fraction;
1154 : :
1155 : : /*
1156 : : * For EXCEPT, we must put the left input first. For INTERSECT, either
1157 : : * order should give the same results, and we prefer to put the smaller
1158 : : * input first in order to (a) minimize the size of the hash table in the
1159 : : * hashing case, and (b) improve our chances of exploiting the executor's
1160 : : * fast path for empty left-hand input. "Smaller" means the one with the
1161 : : * fewer groups.
1162 : : */
502 1163 [ + + + + ]: 624 : if (op->op != SETOP_EXCEPT && dLeftGroups > dRightGroups)
1164 : : {
1165 : : /* need to swap the two inputs */
1166 : : RelOptInfo *tmprel;
1167 : : List *tmplist;
1168 : : double tmpd;
1169 : :
1170 : 30 : tmprel = lrel;
1171 : 30 : lrel = rrel;
1172 : 30 : rrel = tmprel;
1173 : 30 : tmplist = lpath_tlist;
1174 : 30 : lpath_tlist = rpath_tlist;
1175 : 30 : rpath_tlist = tmplist;
1176 : 30 : tmpd = dLeftGroups;
1177 : 30 : dLeftGroups = dRightGroups;
1178 : 30 : dRightGroups = tmpd;
1179 : : }
1180 : :
1181 : 624 : lpath = lrel->cheapest_total_path;
1182 : 624 : rpath = rrel->cheapest_total_path;
1183 : :
1184 : : /* Build result relation. */
2969 rhaas@postgresql.org 1185 : 624 : result_rel = fetch_upper_rel(root, UPPERREL_SETOP,
1186 : 624 : bms_union(lrel->relids, rrel->relids));
1187 : :
1188 : : /*
1189 : : * Create the PathTarget and set the width accordingly. For EXCEPT, since
1190 : : * the set op result won't contain rows from the rpath, we only account
1191 : : * for the width of the lpath. For INTERSECT, use both input paths.
1192 : : */
218 drowley@postgresql.o 1193 [ + + ]:GNC 624 : if (op->op == SETOP_EXCEPT)
1194 : 419 : result_rel->reltarget = create_setop_pathtarget(root, tlist,
1195 : : list_make1(lpath));
1196 : : else
1197 : 205 : result_rel->reltarget = create_setop_pathtarget(root, tlist,
1198 : : list_make2(lpath, rpath));
1199 : :
1200 : : /* Check for provably empty setop inputs and add short-circuit paths. */
210 1201 [ + + ]: 624 : if (op->op == SETOP_EXCEPT)
1202 : : {
1203 : : /*
1204 : : * For EXCEPTs, if the left side is dummy then there's no need to
1205 : : * inspect the right-hand side as scanning the right to find tuples to
1206 : : * remove won't make the left-hand input any more empty.
1207 : : */
1208 [ + + ]: 419 : if (is_dummy_rel(lrel))
1209 : : {
1210 : 5 : mark_dummy_rel(result_rel);
1211 : :
1212 : 5 : return result_rel;
1213 : : }
1214 : :
1215 : : /* Handle EXCEPTs with dummy right input */
1216 [ + + ]: 414 : if (is_dummy_rel(rrel))
1217 : : {
1218 [ + - ]: 5 : if (op->all)
1219 : : {
1220 : : Path *apath;
84 rhaas@postgresql.org 1221 : 5 : AppendPathInput append = {0};
1222 : :
1223 : 5 : append.subpaths = list_make1(lpath);
1224 : :
1225 : : /*
1226 : : * EXCEPT ALL: If the right-hand input is dummy then we can
1227 : : * simply scan the left-hand input. To keep createplan.c
1228 : : * happy, use a single child Append to handle the translation
1229 : : * between the set op targetlist and the targetlist of the
1230 : : * left input. The Append will be removed in setrefs.c.
1231 : : */
1232 : 5 : apath = (Path *) create_append_path(root, result_rel,
1233 : : append, NIL, NULL, 0,
1234 : : false, -1);
1235 : :
210 drowley@postgresql.o 1236 : 5 : add_path(result_rel, apath);
1237 : :
1238 : 5 : return result_rel;
1239 : : }
1240 : : else
1241 : : {
1242 : : /*
1243 : : * To make EXCEPT with a dummy RHS work means having to
1244 : : * deduplicate the left input. That could be done with
1245 : : * AggPaths, but it doesn't seem worth the effort. Let the
1246 : : * normal path generation code below handle this one.
1247 : : */
1248 : : }
1249 : : }
1250 : : }
1251 : : else
1252 : : {
1253 : : /*
1254 : : * For INTERSECT, if either input is a dummy rel then we can mark the
1255 : : * result_rel as dummy since intersecting with an empty relation can
1256 : : * never yield any results. This is true regardless of INTERSECT or
1257 : : * INTERSECT ALL.
1258 : : */
1259 [ + + - + ]: 205 : if (is_dummy_rel(lrel) || is_dummy_rel(rrel))
1260 : : {
1261 : 15 : mark_dummy_rel(result_rel);
1262 : :
1263 : 15 : return result_rel;
1264 : : }
1265 : : }
1266 : :
1267 : : /*
1268 : : * Estimate number of distinct groups that we'll need hashtable entries
1269 : : * for; this is the size of the left-hand input for EXCEPT, or the smaller
1270 : : * input for INTERSECT. Also estimate the number of eventual output rows.
1271 : : * In non-ALL cases, we estimate each group produces one output row; in
1272 : : * ALL cases use the relevant relation size. These are worst-case
1273 : : * estimates, of course, but we need to be conservative.
1274 : : */
6480 tgl@sss.pgh.pa.us 1275 [ + + ]:CBC 599 : if (op->op == SETOP_EXCEPT)
1276 : : {
1277 : 409 : dNumGroups = dLeftGroups;
3711 1278 [ + + ]: 409 : dNumOutputRows = op->all ? lpath->rows : dNumGroups;
1279 : : }
1280 : : else
1281 : : {
502 1282 : 190 : dNumGroups = dLeftGroups;
3711 1283 [ + + - + ]: 190 : dNumOutputRows = op->all ? Min(lpath->rows, rpath->rows) : dNumGroups;
1284 : : }
502 1285 : 599 : result_rel->rows = dNumOutputRows;
1286 : :
1287 : : /* Select the SetOpCmd type */
1288 [ + + - ]: 599 : switch (op->op)
1289 : : {
1290 : 190 : case SETOP_INTERSECT:
1291 : 190 : cmd = op->all ? SETOPCMD_INTERSECT_ALL : SETOPCMD_INTERSECT;
1292 : 190 : break;
1293 : 409 : case SETOP_EXCEPT:
1294 [ + + ]: 409 : cmd = op->all ? SETOPCMD_EXCEPT_ALL : SETOPCMD_EXCEPT;
1295 : 409 : break;
502 tgl@sss.pgh.pa.us 1296 :UBC 0 : default:
1297 [ # # ]: 0 : elog(ERROR, "unrecognized set op: %d", (int) op->op);
1298 : : cmd = SETOPCMD_INTERSECT; /* keep compiler quiet */
1299 : : break;
1300 : : }
1301 : :
1302 : : /*
1303 : : * If we can hash, that just requires a SetOp atop the cheapest inputs.
1304 : : */
502 tgl@sss.pgh.pa.us 1305 [ + + ]:CBC 599 : if (can_hash)
1306 : : {
1307 : 549 : path = (Path *) create_setop_path(root,
1308 : : result_rel,
1309 : : lpath,
1310 : : rpath,
1311 : : cmd,
1312 : : SETOP_HASHED,
1313 : : groupList,
1314 : : dNumGroups,
1315 : : dNumOutputRows);
1316 : 549 : add_path(result_rel, path);
1317 : : }
1318 : :
1319 : : /*
1320 : : * If we can sort, generate the cheapest sorted input paths, and add a
1321 : : * SetOp atop those.
1322 : : */
1323 [ + - ]: 599 : if (can_sort)
1324 : : {
1325 : : List *pathkeys;
1326 : : Path *slpath,
1327 : : *srpath;
1328 : :
1329 : : /* First the left input ... */
1330 : 599 : pathkeys = make_pathkeys_for_sortclauses(root,
1331 : : groupList,
1332 : : lpath_tlist);
1333 [ + + ]: 599 : if (pathkeys_contained_in(pathkeys, lpath->pathkeys))
1334 : 80 : slpath = lpath; /* cheapest path is already sorted */
1335 : : else
1336 : : {
1337 : 519 : slpath = get_cheapest_path_for_pathkeys(lrel->pathlist,
1338 : : nonunion_pathkeys,
1339 : : NULL,
1340 : : TOTAL_COST,
1341 : : false);
1342 : : /* Subquery failed to produce any presorted paths? */
1343 [ + + ]: 519 : if (slpath == NULL)
1344 : 165 : slpath = (Path *) create_sort_path(root,
1345 : : lpath->parent,
1346 : : lpath,
1347 : : pathkeys,
1348 : : -1.0);
1349 : : }
1350 : :
1351 : : /* and now the same for the right. */
1352 : 599 : pathkeys = make_pathkeys_for_sortclauses(root,
1353 : : groupList,
1354 : : rpath_tlist);
1355 [ + + ]: 599 : if (pathkeys_contained_in(pathkeys, rpath->pathkeys))
1356 : 90 : srpath = rpath; /* cheapest path is already sorted */
1357 : : else
1358 : : {
1359 : 509 : srpath = get_cheapest_path_for_pathkeys(rrel->pathlist,
1360 : : nonunion_pathkeys,
1361 : : NULL,
1362 : : TOTAL_COST,
1363 : : false);
1364 : : /* Subquery failed to produce any presorted paths? */
1365 [ + + ]: 509 : if (srpath == NULL)
1366 : 165 : srpath = (Path *) create_sort_path(root,
1367 : : rpath->parent,
1368 : : rpath,
1369 : : pathkeys,
1370 : : -1.0);
1371 : : }
1372 : :
1373 : 599 : path = (Path *) create_setop_path(root,
1374 : : result_rel,
1375 : : slpath,
1376 : : srpath,
1377 : : cmd,
1378 : : SETOP_SORTED,
1379 : : groupList,
1380 : : dNumGroups,
1381 : : dNumOutputRows);
1382 : 599 : add_path(result_rel, path);
1383 : : }
1384 : :
2969 rhaas@postgresql.org 1385 : 599 : return result_rel;
1386 : : }
1387 : :
1388 : : /*
1389 : : * Pull up children of a UNION node that are identically-propertied UNIONs,
1390 : : * and perform planning of the queries underneath the N-way UNION.
1391 : : *
1392 : : * The result is a list of RelOptInfos containing Paths for sub-nodes, with
1393 : : * one entry for each descendant that is a leaf query or non-identical setop.
1394 : : * We also return parallel lists of the childrens' targetlists and
1395 : : * is-trivial-tlist flags.
1396 : : *
1397 : : * NOTE: we can also pull a UNION ALL up into a UNION, since the distinct
1398 : : * output rows will be lost anyway.
1399 : : */
1400 : : static List *
1401 : 3801 : plan_union_children(PlannerInfo *root,
1402 : : SetOperationStmt *top_union,
1403 : : List *refnames_tlist,
1404 : : List **tlist_list,
1405 : : List **istrivial_tlist)
1406 : : {
1407 : 3801 : List *pending_rels = list_make1(top_union);
1408 : 3801 : List *result = NIL;
1409 : : List *child_tlist;
1410 : : bool trivial_tlist;
1411 : :
1412 : 3801 : *tlist_list = NIL;
714 1413 : 3801 : *istrivial_tlist = NIL;
1414 : :
2969 1415 [ + + ]: 21772 : while (pending_rels != NIL)
1416 : : {
1417 : 17971 : Node *setOp = linitial(pending_rels);
1418 : :
1419 : 17971 : pending_rels = list_delete_first(pending_rels);
1420 : :
1421 [ + + ]: 17971 : if (IsA(setOp, SetOperationStmt))
1422 : : {
1423 : 7195 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1424 : :
1425 [ + + ]: 7195 : if (op->op == top_union->op &&
1426 [ + + + + : 14215 : (op->all == top_union->all || op->all) &&
+ + ]
532 tgl@sss.pgh.pa.us 1427 [ + - ]: 14185 : equal(op->colTypes, top_union->colTypes) &&
1428 : 7085 : equal(op->colCollations, top_union->colCollations))
1429 : : {
1430 : : /* Same UNION, so fold children into parent */
2969 rhaas@postgresql.org 1431 : 7085 : pending_rels = lcons(op->rarg, pending_rels);
1432 : 7085 : pending_rels = lcons(op->larg, pending_rels);
1433 : 7085 : continue;
1434 : : }
1435 : : }
1436 : :
1437 : : /*
1438 : : * Not same, so plan this child separately.
1439 : : *
1440 : : * If top_union isn't a UNION ALL, then we are interested in sorted
1441 : : * output from the child, so pass top_union as parentOp. Note that
1442 : : * this isn't necessarily the child node's immediate SetOperationStmt
1443 : : * parent, but that's fine: it's the effective parent.
1444 : : */
1445 : 10886 : result = lappend(result, recurse_set_operations(setOp, root,
502 tgl@sss.pgh.pa.us 1446 [ + + ]: 10886 : top_union->all ? NULL : top_union,
1447 : : top_union->colTypes,
1448 : : top_union->colCollations,
1449 : : refnames_tlist,
1450 : : &child_tlist,
1451 : : &trivial_tlist));
2969 rhaas@postgresql.org 1452 : 10886 : *tlist_list = lappend(*tlist_list, child_tlist);
714 1453 : 10886 : *istrivial_tlist = lappend_int(*istrivial_tlist, trivial_tlist);
1454 : : }
1455 : :
3711 tgl@sss.pgh.pa.us 1456 : 3801 : return result;
1457 : : }
1458 : :
1459 : : /*
1460 : : * postprocess_setop_rel - perform steps required after adding paths
1461 : : */
1462 : : static void
2969 rhaas@postgresql.org 1463 : 18492 : postprocess_setop_rel(PlannerInfo *root, RelOptInfo *rel)
1464 : : {
1465 : : /*
1466 : : * We don't currently worry about allowing FDWs to contribute paths to
1467 : : * this relation, but give extensions a chance.
1468 : : */
1469 [ - + ]: 18492 : if (create_upper_paths_hook)
2969 rhaas@postgresql.org 1470 :UBC 0 : (*create_upper_paths_hook) (root, UPPERREL_SETOP,
1471 : : NULL, rel, NULL);
1472 : :
1473 : : /* Select cheapest path */
2969 rhaas@postgresql.org 1474 :CBC 18492 : set_cheapest(rel);
1475 : 18492 : }
1476 : :
1477 : : /*
1478 : : * Generate targetlist for a set-operation plan node
1479 : : *
1480 : : * colTypes: OID list of set-op's result column datatypes
1481 : : * colCollations: OID list of set-op's result column collations
1482 : : * varno: varno to use in generated Vars
1483 : : * hack_constants: true to copy up constants (see comments in code)
1484 : : * input_tlist: targetlist of this node's input node
1485 : : * refnames_tlist: targetlist to take column names from
1486 : : * trivial_tlist: output parameter, set to true if targetlist is trivial
1487 : : */
1488 : : static List *
5498 tgl@sss.pgh.pa.us 1489 : 14016 : generate_setop_tlist(List *colTypes, List *colCollations,
1490 : : Index varno,
1491 : : bool hack_constants,
1492 : : List *input_tlist,
1493 : : List *refnames_tlist,
1494 : : bool *trivial_tlist)
1495 : : {
9343 1496 : 14016 : List *tlist = NIL;
1497 : 14016 : int resno = 1;
1498 : : ListCell *ctlc,
1499 : : *cclc,
1500 : : *itlc,
1501 : : *rtlc;
1502 : : TargetEntry *tle;
1503 : : Node *expr;
1504 : :
1386 1505 : 14016 : *trivial_tlist = true; /* until proven differently */
1506 : :
2623 1507 [ + + + + : 56525 : forfour(ctlc, colTypes, cclc, colCollations,
+ + + + +
+ + + + +
+ + + + +
- + - + -
+ + ]
1508 : : itlc, input_tlist, rtlc, refnames_tlist)
1509 : : {
5498 1510 : 42509 : Oid colType = lfirst_oid(ctlc);
1511 : 42509 : Oid colColl = lfirst_oid(cclc);
1512 : 42509 : TargetEntry *inputtle = (TargetEntry *) lfirst(itlc);
1513 : 42509 : TargetEntry *reftle = (TargetEntry *) lfirst(rtlc);
1514 : :
7699 1515 [ - + ]: 42509 : Assert(inputtle->resno == resno);
1516 [ - + ]: 42509 : Assert(reftle->resno == resno);
1517 [ - + ]: 42509 : Assert(!inputtle->resjunk);
1518 [ - + ]: 42509 : Assert(!reftle->resjunk);
1519 : :
1520 : : /*
1521 : : * Generate columns referencing input columns and having appropriate
1522 : : * data types and column names. Insert datatype coercions where
1523 : : * necessary.
1524 : : *
1525 : : * HACK: constants in the input's targetlist are copied up as-is
1526 : : * rather than being referenced as subquery outputs. This is mainly
1527 : : * to ensure that when we try to coerce them to the output column's
1528 : : * datatype, the right things happen for UNKNOWN constants. But do
1529 : : * this only at the first level of subquery-scan plans; we don't want
1530 : : * phony constants appearing in the output tlists of upper-level
1531 : : * nodes!
1532 : : *
1533 : : * Note that copying a constant doesn't in itself require us to mark
1534 : : * the tlist nontrivial; see trivial_subqueryscan() in setrefs.c.
1535 : : */
9308 1536 [ + + + - : 42509 : if (hack_constants && inputtle->expr && IsA(inputtle->expr, Const))
+ + ]
8545 1537 : 13206 : expr = (Node *) inputtle->expr;
1538 : : else
7653 1539 : 117212 : expr = (Node *) makeVar(varno,
7699 1540 : 29303 : inputtle->resno,
1541 : 29303 : exprType((Node *) inputtle->expr),
1542 : 29303 : exprTypmod((Node *) inputtle->expr),
5565 peter_e@gmx.net 1543 : 29303 : exprCollation((Node *) inputtle->expr),
1544 : : 0);
1545 : :
7699 tgl@sss.pgh.pa.us 1546 [ + + ]: 42509 : if (exprType(expr) != colType)
1547 : : {
1548 : : /*
1549 : : * Note: it's not really cool to be applying coerce_to_common_type
1550 : : * here; one notable point is that assign_expr_collations never
1551 : : * gets run on any generated nodes. For the moment that's not a
1552 : : * problem because we force the correct exposed collation below.
1553 : : * It would likely be best to make the parser generate the correct
1554 : : * output tlist for every set-op to begin with, though.
1555 : : */
8310 bruce@momjian.us 1556 : 1353 : expr = coerce_to_common_type(NULL, /* no UNKNOWNs here */
1557 : : expr,
1558 : : colType,
1559 : : "UNION/INTERSECT/EXCEPT");
1386 tgl@sss.pgh.pa.us 1560 : 1353 : *trivial_tlist = false; /* the coercion makes it not trivial */
1561 : : }
1562 : :
1563 : : /*
1564 : : * Ensure the tlist entry's exposed collation matches the set-op. This
1565 : : * is necessary because plan_set_operations() reports the result
1566 : : * ordering as a list of SortGroupClauses, which don't carry collation
1567 : : * themselves but just refer to tlist entries. If we don't show the
1568 : : * right collation then planner.c might do the wrong thing in
1569 : : * higher-level queries.
1570 : : *
1571 : : * Note we use RelabelType, not CollateExpr, since this expression
1572 : : * will reach the executor without any further processing.
1573 : : */
5498 1574 [ + + ]: 42509 : if (exprCollation(expr) != colColl)
1575 : : {
2085 1576 : 10915 : expr = applyRelabelType(expr,
1577 : : exprType(expr), exprTypmod(expr), colColl,
1578 : : COERCE_IMPLICIT_CAST, -1, false);
1386 1579 : 10915 : *trivial_tlist = false; /* the relabel makes it not trivial */
1580 : : }
1581 : :
7699 1582 : 85018 : tle = makeTargetEntry((Expr *) expr,
1583 : 42509 : (AttrNumber) resno++,
1584 : 42509 : pstrdup(reftle->resname),
1585 : : false);
1586 : :
1587 : : /*
1588 : : * By convention, all output columns in a setop tree have
1589 : : * ressortgroupref equal to their resno. In some cases the ref isn't
1590 : : * needed, but this is a cleaner way than modifying the tlist later.
1591 : : */
3711 1592 : 42509 : tle->ressortgroupref = tle->resno;
1593 : :
7699 1594 : 42509 : tlist = lappend(tlist, tle);
1595 : : }
1596 : :
9343 1597 : 14016 : return tlist;
1598 : : }
1599 : :
1600 : : /*
1601 : : * Generate targetlist for a set-operation Append node
1602 : : *
1603 : : * colTypes: OID list of set-op's result column datatypes
1604 : : * colCollations: OID list of set-op's result column collations
1605 : : * input_tlists: list of tlists for sub-plans of the Append
1606 : : * refnames_tlist: targetlist to take column names from
1607 : : *
1608 : : * The entries in the Append's targetlist should always be simple Vars;
1609 : : * we just have to make sure they have the right datatypes/typmods/collations.
1610 : : * The Vars are always generated with varno 0.
1611 : : *
1612 : : * XXX a problem with the varno-zero approach is that set_pathtarget_cost_width
1613 : : * cannot figure out a realistic width for the tlist we make here. But we
1614 : : * ought to refactor this code to produce a PathTarget directly, anyway.
1615 : : */
1616 : : static List *
5498 1617 : 4495 : generate_append_tlist(List *colTypes, List *colCollations,
1618 : : List *input_tlists,
1619 : : List *refnames_tlist)
1620 : : {
8827 1621 : 4495 : List *tlist = NIL;
1622 : 4495 : int resno = 1;
1623 : : ListCell *curColType;
1624 : : ListCell *curColCollation;
1625 : : ListCell *ref_tl_item;
1626 : : int colindex;
1627 : : TargetEntry *tle;
1628 : : Node *expr;
1629 : : ListCell *tlistl;
1630 : : int32 *colTypmods;
1631 : :
1632 : : /*
1633 : : * First extract typmods to use.
1634 : : *
1635 : : * If the inputs all agree on type and typmod of a particular column, use
1636 : : * that typmod; else use -1.
1637 : : */
146 michael@paquier.xyz 1638 :GNC 4495 : colTypmods = palloc_array(int32, list_length(colTypes));
1639 : :
3711 tgl@sss.pgh.pa.us 1640 [ + - + + :CBC 16769 : foreach(tlistl, input_tlists)
+ + ]
1641 : : {
1642 : 12274 : List *subtlist = (List *) lfirst(tlistl);
1643 : : ListCell *subtlistl;
1644 : :
8014 neilc@samurai.com 1645 : 12274 : curColType = list_head(colTypes);
8827 tgl@sss.pgh.pa.us 1646 : 12274 : colindex = 0;
3711 1647 [ + + + + : 48272 : foreach(subtlistl, subtlist)
+ + ]
1648 : : {
1649 : 35998 : TargetEntry *subtle = (TargetEntry *) lfirst(subtlistl);
1650 : :
502 1651 [ - + ]: 35998 : Assert(!subtle->resjunk);
8014 neilc@samurai.com 1652 [ - + ]: 35998 : Assert(curColType != NULL);
7699 tgl@sss.pgh.pa.us 1653 [ + - ]: 35998 : if (exprType((Node *) subtle->expr) == lfirst_oid(curColType))
1654 : : {
1655 : : /* If first subplan, copy the typmod; else compare */
1656 : 35998 : int32 subtypmod = exprTypmod((Node *) subtle->expr);
1657 : :
3711 1658 [ + + ]: 35998 : if (tlistl == list_head(input_tlists))
7699 1659 : 12348 : colTypmods[colindex] = subtypmod;
1660 [ + + ]: 23650 : else if (subtypmod != colTypmods[colindex])
8827 1661 : 10 : colTypmods[colindex] = -1;
1662 : : }
1663 : : else
1664 : : {
1665 : : /* types disagree, so force typmod to -1 */
8827 tgl@sss.pgh.pa.us 1666 :UBC 0 : colTypmods[colindex] = -1;
1667 : : }
2486 tgl@sss.pgh.pa.us 1668 :CBC 35998 : curColType = lnext(colTypes, curColType);
8827 1669 : 35998 : colindex++;
1670 : : }
8014 neilc@samurai.com 1671 [ - + ]: 12274 : Assert(curColType == NULL);
1672 : : }
1673 : :
1674 : : /*
1675 : : * Now we can build the tlist for the Append.
1676 : : */
8827 tgl@sss.pgh.pa.us 1677 : 4495 : colindex = 0;
5498 1678 [ + + + + : 16843 : forthree(curColType, colTypes, curColCollation, colCollations,
+ + + + +
+ + + + +
+ - + - +
+ ]
1679 : : ref_tl_item, refnames_tlist)
1680 : : {
8010 neilc@samurai.com 1681 : 12348 : Oid colType = lfirst_oid(curColType);
8827 tgl@sss.pgh.pa.us 1682 : 12348 : int32 colTypmod = colTypmods[colindex++];
5565 peter_e@gmx.net 1683 : 12348 : Oid colColl = lfirst_oid(curColCollation);
8014 neilc@samurai.com 1684 : 12348 : TargetEntry *reftle = (TargetEntry *) lfirst(ref_tl_item);
1685 : :
7699 tgl@sss.pgh.pa.us 1686 [ - + ]: 12348 : Assert(reftle->resno == resno);
1687 [ - + ]: 12348 : Assert(!reftle->resjunk);
8827 1688 : 12348 : expr = (Node *) makeVar(0,
1689 : : resno,
1690 : : colType,
1691 : : colTypmod,
1692 : : colColl,
1693 : : 0);
7699 1694 : 24696 : tle = makeTargetEntry((Expr *) expr,
1695 : 12348 : (AttrNumber) resno++,
1696 : 12348 : pstrdup(reftle->resname),
1697 : : false);
1698 : :
1699 : : /*
1700 : : * By convention, all output columns in a setop tree have
1701 : : * ressortgroupref equal to their resno. In some cases the ref isn't
1702 : : * needed, but this is a cleaner way than modifying the tlist later.
1703 : : */
3711 1704 : 12348 : tle->ressortgroupref = tle->resno;
1705 : :
7699 1706 : 12348 : tlist = lappend(tlist, tle);
1707 : : }
1708 : :
8827 1709 : 4495 : pfree(colTypmods);
1710 : :
1711 : 4495 : return tlist;
1712 : : }
1713 : :
1714 : : /*
1715 : : * generate_setop_grouplist
1716 : : * Build a SortGroupClause list defining the sort/grouping properties
1717 : : * of the setop's output columns.
1718 : : *
1719 : : * Parse analysis already determined the properties and built a suitable
1720 : : * list, except that the entries do not have sortgrouprefs set because
1721 : : * the parser output representation doesn't include a tlist for each
1722 : : * setop. So what we need to do here is copy that list and install
1723 : : * proper sortgrouprefs into it (copying those from the targetlist).
1724 : : */
1725 : : static List *
6480 1726 : 4185 : generate_setop_grouplist(SetOperationStmt *op, List *targetlist)
1727 : : {
3344 peter_e@gmx.net 1728 : 4185 : List *grouplist = copyObject(op->groupClauses);
1729 : : ListCell *lg;
1730 : : ListCell *lt;
1731 : :
6480 tgl@sss.pgh.pa.us 1732 : 4185 : lg = list_head(grouplist);
1733 [ + + + + : 16103 : foreach(lt, targetlist)
+ + ]
1734 : : {
1735 : 11918 : TargetEntry *tle = (TargetEntry *) lfirst(lt);
1736 : : SortGroupClause *sgc;
1737 : :
502 1738 [ - + ]: 11918 : Assert(!tle->resjunk);
1739 : :
1740 : : /* non-resjunk columns should have sortgroupref = resno */
3711 1741 [ - + ]: 11918 : Assert(tle->ressortgroupref == tle->resno);
1742 : :
1743 : : /* non-resjunk columns should have grouping clauses */
6480 1744 [ - + ]: 11918 : Assert(lg != NULL);
1745 : 11918 : sgc = (SortGroupClause *) lfirst(lg);
2486 1746 : 11918 : lg = lnext(grouplist, lg);
6480 1747 [ - + ]: 11918 : Assert(sgc->tleSortGroupRef == 0);
1748 : :
3711 1749 : 11918 : sgc->tleSortGroupRef = tle->ressortgroupref;
1750 : : }
6480 1751 [ - + ]: 4185 : Assert(lg == NULL);
1752 : 4185 : return grouplist;
1753 : : }
1754 : :
1755 : : /*
1756 : : * create_setop_pathtarget
1757 : : * Do the normal create_pathtarget() work, plus set the resulting
1758 : : * PathTarget's width to the average width of the Paths in child_pathlist
1759 : : * weighted using the estimated row count of each path.
1760 : : *
1761 : : * Note: This is required because set op target lists use varno==0, which
1762 : : * results in a type default width estimate rather than one that's based on
1763 : : * statistics of the columns from the set op children.
1764 : : */
1765 : : static PathTarget *
218 drowley@postgresql.o 1766 :GNC 4425 : create_setop_pathtarget(PlannerInfo *root, List *tlist, List *child_pathlist)
1767 : : {
1768 : : PathTarget *reltarget;
1769 : : ListCell *lc;
1770 : 4425 : double parent_rows = 0;
1771 : 4425 : double parent_size = 0;
1772 : :
1773 : 4425 : reltarget = create_pathtarget(root, tlist);
1774 : :
1775 : : /* Calculate the total rows and total size. */
1776 [ + + + + : 16098 : foreach(lc, child_pathlist)
+ + ]
1777 : : {
1778 : 11673 : Path *path = (Path *) lfirst(lc);
1779 : :
1780 : 11673 : parent_rows += path->rows;
1781 : 11673 : parent_size += path->parent->reltarget->width * path->rows;
1782 : : }
1783 : :
1784 [ + + ]: 4425 : if (parent_rows > 0)
1785 : 4410 : reltarget->width = rint(parent_size / parent_rows);
1786 : :
1787 : 4425 : return reltarget;
1788 : : }
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