Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * allpaths.c
4 : : * Routines to find possible search paths for processing a query
5 : : *
6 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : : * Portions Copyright (c) 1994, Regents of the University of California
8 : : *
9 : : *
10 : : * IDENTIFICATION
11 : : * src/backend/optimizer/path/allpaths.c
12 : : *
13 : : *-------------------------------------------------------------------------
14 : : */
15 : :
16 : : #include "postgres.h"
17 : :
18 : : #include <limits.h>
19 : : #include <math.h>
20 : :
21 : : #include "access/sysattr.h"
22 : : #include "access/tsmapi.h"
23 : : #include "catalog/pg_class.h"
24 : : #include "catalog/pg_operator.h"
25 : : #include "catalog/pg_proc.h"
26 : : #include "foreign/fdwapi.h"
27 : : #include "miscadmin.h"
28 : : #include "nodes/makefuncs.h"
29 : : #include "nodes/nodeFuncs.h"
30 : : #include "nodes/supportnodes.h"
31 : : #ifdef OPTIMIZER_DEBUG
32 : : #include "nodes/print.h"
33 : : #endif
34 : : #include "optimizer/appendinfo.h"
35 : : #include "optimizer/clauses.h"
36 : : #include "optimizer/cost.h"
37 : : #include "optimizer/geqo.h"
38 : : #include "optimizer/optimizer.h"
39 : : #include "optimizer/pathnode.h"
40 : : #include "optimizer/paths.h"
41 : : #include "optimizer/plancat.h"
42 : : #include "optimizer/planner.h"
43 : : #include "optimizer/prep.h"
44 : : #include "optimizer/tlist.h"
45 : : #include "parser/parse_clause.h"
46 : : #include "parser/parsetree.h"
47 : : #include "partitioning/partbounds.h"
48 : : #include "port/pg_bitutils.h"
49 : : #include "rewrite/rewriteManip.h"
50 : : #include "utils/lsyscache.h"
51 : : #include "utils/selfuncs.h"
52 : :
53 : :
54 : : /* Bitmask flags for pushdown_safety_info.unsafeFlags */
55 : : #define UNSAFE_HAS_VOLATILE_FUNC (1 << 0)
56 : : #define UNSAFE_HAS_SET_FUNC (1 << 1)
57 : : #define UNSAFE_NOTIN_DISTINCTON_CLAUSE (1 << 2)
58 : : #define UNSAFE_NOTIN_PARTITIONBY_CLAUSE (1 << 3)
59 : : #define UNSAFE_TYPE_MISMATCH (1 << 4)
60 : :
61 : : /* results of subquery_is_pushdown_safe */
62 : : typedef struct pushdown_safety_info
63 : : {
64 : : unsigned char *unsafeFlags; /* bitmask of reasons why this target list
65 : : * column is unsafe for qual pushdown, or 0 if
66 : : * no reason. */
67 : : bool unsafeVolatile; /* don't push down volatile quals */
68 : : bool unsafeLeaky; /* don't push down leaky quals */
69 : : } pushdown_safety_info;
70 : :
71 : : /* Return type for qual_is_pushdown_safe */
72 : : typedef enum pushdown_safe_type
73 : : {
74 : : PUSHDOWN_UNSAFE, /* unsafe to push qual into subquery */
75 : : PUSHDOWN_SAFE, /* safe to push qual into subquery */
76 : : PUSHDOWN_WINDOWCLAUSE_RUNCOND, /* unsafe, but may work as WindowClause
77 : : * run condition */
78 : : } pushdown_safe_type;
79 : :
80 : : /* These parameters are set by GUC */
81 : : bool enable_geqo = false; /* just in case GUC doesn't set it */
82 : : bool enable_eager_aggregate = true;
83 : : int geqo_threshold;
84 : : double min_eager_agg_group_size;
85 : : int min_parallel_table_scan_size;
86 : : int min_parallel_index_scan_size;
87 : :
88 : : /* Hook for plugins to get control in set_rel_pathlist() */
89 : : set_rel_pathlist_hook_type set_rel_pathlist_hook = NULL;
90 : :
91 : : /* Hook for plugins to replace standard_join_search() */
92 : : join_search_hook_type join_search_hook = NULL;
93 : :
94 : :
95 : : static void set_base_rel_consider_startup(PlannerInfo *root);
96 : : static void set_base_rel_sizes(PlannerInfo *root);
97 : : static void setup_simple_grouped_rels(PlannerInfo *root);
98 : : static void set_base_rel_pathlists(PlannerInfo *root);
99 : : static void set_rel_size(PlannerInfo *root, RelOptInfo *rel,
100 : : Index rti, RangeTblEntry *rte);
101 : : static void set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
102 : : Index rti, RangeTblEntry *rte);
103 : : static void set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel,
104 : : RangeTblEntry *rte);
105 : : static void create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel);
106 : : static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
107 : : RangeTblEntry *rte);
108 : : static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
109 : : RangeTblEntry *rte);
110 : : static void set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel,
111 : : RangeTblEntry *rte);
112 : : static void set_tablesample_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
113 : : RangeTblEntry *rte);
114 : : static void set_foreign_size(PlannerInfo *root, RelOptInfo *rel,
115 : : RangeTblEntry *rte);
116 : : static void set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel,
117 : : RangeTblEntry *rte);
118 : : static void set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
119 : : Index rti, RangeTblEntry *rte);
120 : : static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
121 : : Index rti, RangeTblEntry *rte);
122 : : static void set_grouped_rel_pathlist(PlannerInfo *root, RelOptInfo *rel);
123 : : static void generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel,
124 : : List *live_childrels,
125 : : List *all_child_pathkeys);
126 : : static Path *get_cheapest_parameterized_child_path(PlannerInfo *root,
127 : : RelOptInfo *rel,
128 : : Relids required_outer);
129 : : static void accumulate_append_subpath(Path *path,
130 : : List **subpaths,
131 : : List **special_subpaths,
132 : : List **child_append_relid_sets);
133 : : static Path *get_singleton_append_subpath(Path *path,
134 : : List **child_append_relid_sets);
135 : : static void set_dummy_rel_pathlist(RelOptInfo *rel);
136 : : static void set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
137 : : Index rti, RangeTblEntry *rte);
138 : : static void set_function_pathlist(PlannerInfo *root, RelOptInfo *rel,
139 : : RangeTblEntry *rte);
140 : : static void set_values_pathlist(PlannerInfo *root, RelOptInfo *rel,
141 : : RangeTblEntry *rte);
142 : : static void set_tablefunc_pathlist(PlannerInfo *root, RelOptInfo *rel,
143 : : RangeTblEntry *rte);
144 : : static void set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel,
145 : : RangeTblEntry *rte);
146 : : static void set_namedtuplestore_pathlist(PlannerInfo *root, RelOptInfo *rel,
147 : : RangeTblEntry *rte);
148 : : static void set_result_pathlist(PlannerInfo *root, RelOptInfo *rel,
149 : : RangeTblEntry *rte);
150 : : static void set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel,
151 : : RangeTblEntry *rte);
152 : : static RelOptInfo *make_rel_from_joinlist(PlannerInfo *root, List *joinlist);
153 : : static bool subquery_is_pushdown_safe(Query *subquery, Query *topquery,
154 : : pushdown_safety_info *safetyInfo);
155 : : static bool recurse_pushdown_safe(Node *setOp, Query *topquery,
156 : : pushdown_safety_info *safetyInfo);
157 : : static void check_output_expressions(Query *subquery,
158 : : pushdown_safety_info *safetyInfo);
159 : : static void compare_tlist_datatypes(List *tlist, List *colTypes,
160 : : pushdown_safety_info *safetyInfo);
161 : : static bool targetIsInAllPartitionLists(TargetEntry *tle, Query *query);
162 : : static pushdown_safe_type qual_is_pushdown_safe(Query *subquery, Index rti,
163 : : RestrictInfo *rinfo,
164 : : pushdown_safety_info *safetyInfo);
165 : : static void subquery_push_qual(Query *subquery,
166 : : RangeTblEntry *rte, Index rti, Node *qual);
167 : : static void recurse_push_qual(Node *setOp, Query *topquery,
168 : : RangeTblEntry *rte, Index rti, Node *qual);
169 : : static void remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel,
170 : : Bitmapset *extra_used_attrs);
171 : :
172 : :
173 : : /*
174 : : * make_one_rel
175 : : * Finds all possible access paths for executing a query, returning a
176 : : * single rel that represents the join of all base rels in the query.
177 : : */
178 : : RelOptInfo *
7390 tgl@sss.pgh.pa.us 179 :CBC 184685 : make_one_rel(PlannerInfo *root, List *joinlist)
180 : : {
181 : : RelOptInfo *rel;
182 : : Index rti;
183 : : double total_pages;
184 : :
185 : : /* Mark base rels as to whether we care about fast-start plans */
3938 186 : 184685 : set_base_rel_consider_startup(root);
187 : :
188 : : /*
189 : : * Compute size estimates and consider_parallel flags for each base rel.
190 : : */
5161 191 : 184685 : set_base_rel_sizes(root);
192 : :
193 : : /*
194 : : * Build grouped relations for simple rels (i.e., base or "other" member
195 : : * relations) where possible.
196 : : */
158 rguo@postgresql.org 197 :GNC 184668 : setup_simple_grouped_rels(root);
198 : :
199 : : /*
200 : : * We should now have size estimates for every actual table involved in
201 : : * the query, and we also know which if any have been deleted from the
202 : : * query by join removal, pruned by partition pruning, or eliminated by
203 : : * constraint exclusion. So we can now compute total_table_pages.
204 : : *
205 : : * Note that appendrels are not double-counted here, even though we don't
206 : : * bother to distinguish RelOptInfos for appendrel parents, because the
207 : : * parents will have pages = 0.
208 : : *
209 : : * XXX if a table is self-joined, we will count it once per appearance,
210 : : * which perhaps is the wrong thing ... but that's not completely clear,
211 : : * and detecting self-joins here is difficult, so ignore it for now.
212 : : */
2685 tgl@sss.pgh.pa.us 213 :CBC 184668 : total_pages = 0;
214 [ + + ]: 572451 : for (rti = 1; rti < root->simple_rel_array_size; rti++)
215 : : {
216 : 387783 : RelOptInfo *brel = root->simple_rel_array[rti];
217 : :
218 : : /* there may be empty slots corresponding to non-baserel RTEs */
219 [ + + ]: 387783 : if (brel == NULL)
220 : 92173 : continue;
221 : :
222 [ - + ]: 295610 : Assert(brel->relid == rti); /* sanity check on array */
223 : :
224 [ + + ]: 295610 : if (IS_DUMMY_REL(brel))
225 : 752 : continue;
226 : :
227 [ + + + - ]: 294858 : if (IS_SIMPLE_REL(brel))
228 : 294858 : total_pages += (double) brel->pages;
229 : : }
230 : 184668 : root->total_table_pages = total_pages;
231 : :
232 : : /*
233 : : * Generate access paths for each base rel.
234 : : */
9254 235 : 184668 : set_base_rel_pathlists(root);
236 : :
237 : : /*
238 : : * Generate access paths for the entire join tree.
239 : : */
7390 240 : 184668 : rel = make_rel_from_joinlist(root, joinlist);
241 : :
242 : : /*
243 : : * The result should join all and only the query's base + outer-join rels.
244 : : */
1140 245 [ - + ]: 184668 : Assert(bms_equal(rel->relids, root->all_query_rels));
246 : :
5161 247 : 184668 : return rel;
248 : : }
249 : :
250 : : /*
251 : : * set_base_rel_consider_startup
252 : : * Set the consider_[param_]startup flags for each base-relation entry.
253 : : *
254 : : * For the moment, we only deal with consider_param_startup here; because the
255 : : * logic for consider_startup is pretty trivial and is the same for every base
256 : : * relation, we just let build_simple_rel() initialize that flag correctly to
257 : : * start with. If that logic ever gets more complicated it would probably
258 : : * be better to move it here.
259 : : */
260 : : static void
3938 261 : 184685 : set_base_rel_consider_startup(PlannerInfo *root)
262 : : {
263 : : /*
264 : : * Since parameterized paths can only be used on the inside of a nestloop
265 : : * join plan, there is usually little value in considering fast-start
266 : : * plans for them. However, for relations that are on the RHS of a SEMI
267 : : * or ANTI join, a fast-start plan can be useful because we're only going
268 : : * to care about fetching one tuple anyway.
269 : : *
270 : : * To minimize growth of planning time, we currently restrict this to
271 : : * cases where the RHS is a single base relation, not a join; there is no
272 : : * provision for consider_param_startup to get set at all on joinrels.
273 : : * Also we don't worry about appendrels. costsize.c's costing rules for
274 : : * nestloop semi/antijoins don't consider such cases either.
275 : : */
276 : : ListCell *lc;
277 : :
278 [ + + + + : 209569 : foreach(lc, root->join_info_list)
+ + ]
279 : : {
280 : 24884 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
281 : : int varno;
282 : :
283 [ + + + + : 31035 : if ((sjinfo->jointype == JOIN_SEMI || sjinfo->jointype == JOIN_ANTI) &&
+ + ]
284 : 6151 : bms_get_singleton_member(sjinfo->syn_righthand, &varno))
285 : : {
286 : 6036 : RelOptInfo *rel = find_base_rel(root, varno);
287 : :
288 : 6036 : rel->consider_param_startup = true;
289 : : }
290 : : }
291 : 184685 : }
292 : :
293 : : /*
294 : : * set_base_rel_sizes
295 : : * Set the size estimates (rows and widths) for each base-relation entry.
296 : : * Also determine whether to consider parallel paths for base relations.
297 : : *
298 : : * We do this in a separate pass over the base rels so that rowcount
299 : : * estimates are available for parameterized path generation, and also so
300 : : * that each rel's consider_parallel flag is set correctly before we begin to
301 : : * generate paths.
302 : : */
303 : : static void
5161 304 : 184685 : set_base_rel_sizes(PlannerInfo *root)
305 : : {
306 : : Index rti;
307 : :
308 [ + + ]: 572469 : for (rti = 1; rti < root->simple_rel_array_size; rti++)
309 : : {
310 : 387801 : RelOptInfo *rel = root->simple_rel_array[rti];
311 : : RangeTblEntry *rte;
312 : :
313 : : /* there may be empty slots corresponding to non-baserel RTEs */
314 [ + + ]: 387801 : if (rel == NULL)
315 : 92174 : continue;
316 : :
3189 317 [ - + ]: 295627 : Assert(rel->relid == rti); /* sanity check on array */
318 : :
319 : : /* ignore RTEs that are "other rels" */
5161 320 [ + + ]: 295627 : if (rel->reloptkind != RELOPT_BASEREL)
321 : 30881 : continue;
322 : :
3777 rhaas@postgresql.org 323 : 264746 : rte = root->simple_rte_array[rti];
324 : :
325 : : /*
326 : : * If parallelism is allowable for this query in general, see whether
327 : : * it's allowable for this rel in particular. We have to do this
328 : : * before set_rel_size(), because (a) if this rel is an inheritance
329 : : * parent, set_append_rel_size() will use and perhaps change the rel's
330 : : * consider_parallel flag, and (b) for some RTE types, set_rel_size()
331 : : * goes ahead and makes paths immediately.
332 : : */
333 [ + + ]: 264746 : if (root->glob->parallelModeOK)
334 : 210323 : set_rel_consider_parallel(root, rel, rte);
335 : :
336 : 264746 : set_rel_size(root, rel, rti, rte);
337 : : }
10841 scrappy@hub.org 338 : 184668 : }
339 : :
340 : : /*
341 : : * setup_simple_grouped_rels
342 : : * For each simple relation, build a grouped simple relation if eager
343 : : * aggregation is possible and if this relation can produce grouped paths.
344 : : */
345 : : static void
158 rguo@postgresql.org 346 :GNC 184668 : setup_simple_grouped_rels(PlannerInfo *root)
347 : : {
348 : : Index rti;
349 : :
350 : : /*
351 : : * If there are no aggregate expressions or grouping expressions, eager
352 : : * aggregation is not possible.
353 : : */
354 [ + + ]: 184668 : if (root->agg_clause_list == NIL ||
355 [ + + ]: 329 : root->group_expr_list == NIL)
356 : 184372 : return;
357 : :
358 [ + + ]: 2537 : for (rti = 1; rti < root->simple_rel_array_size; rti++)
359 : : {
360 : 2241 : RelOptInfo *rel = root->simple_rel_array[rti];
361 : :
362 : : /* there may be empty slots corresponding to non-baserel RTEs */
363 [ + + ]: 2241 : if (rel == NULL)
364 : 707 : continue;
365 : :
366 [ - + ]: 1534 : Assert(rel->relid == rti); /* sanity check on array */
367 [ + + - + ]: 1534 : Assert(IS_SIMPLE_REL(rel)); /* sanity check on rel */
368 : :
369 : 1534 : (void) build_simple_grouped_rel(root, rel);
370 : : }
371 : : }
372 : :
373 : : /*
374 : : * set_base_rel_pathlists
375 : : * Finds all paths available for scanning each base-relation entry.
376 : : * Sequential scan and any available indices are considered.
377 : : * Each useful path is attached to its relation's 'pathlist' field.
378 : : */
379 : : static void
7588 tgl@sss.pgh.pa.us 380 :CBC 184668 : set_base_rel_pathlists(PlannerInfo *root)
381 : : {
382 : : Index rti;
383 : :
7348 384 [ + + ]: 572451 : for (rti = 1; rti < root->simple_rel_array_size; rti++)
385 : : {
386 : 387783 : RelOptInfo *rel = root->simple_rel_array[rti];
387 : :
388 : : /* there may be empty slots corresponding to non-baserel RTEs */
7587 389 [ + + ]: 387783 : if (rel == NULL)
390 : 92173 : continue;
391 : :
3189 392 [ - + ]: 295610 : Assert(rel->relid == rti); /* sanity check on array */
393 : :
394 : : /* ignore RTEs that are "other rels" */
7587 395 [ + + ]: 295610 : if (rel->reloptkind != RELOPT_BASEREL)
396 : 30881 : continue;
397 : :
6903 398 : 264729 : set_rel_pathlist(root, rel, rti, root->simple_rte_array[rti]);
399 : : }
7345 400 : 184668 : }
401 : :
402 : : /*
403 : : * set_rel_size
404 : : * Set size estimates for a base relation
405 : : */
406 : : static void
5161 407 : 295466 : set_rel_size(PlannerInfo *root, RelOptInfo *rel,
408 : : Index rti, RangeTblEntry *rte)
409 : : {
5286 410 [ + + + + ]: 560212 : if (rel->reloptkind == RELOPT_BASEREL &&
411 : 264746 : relation_excluded_by_constraints(root, rel, rte))
412 : : {
413 : : /*
414 : : * We proved we don't need to scan the rel via constraint exclusion,
415 : : * so set up a single dummy path for it. Here we only check this for
416 : : * regular baserels; if it's an otherrel, CE was already checked in
417 : : * set_append_rel_size().
418 : : *
419 : : * In this case, we go ahead and set up the relation's path right away
420 : : * instead of leaving it for set_rel_pathlist to do. This is because
421 : : * we don't have a convention for marking a rel as dummy except by
422 : : * assigning a dummy path to it.
423 : : */
424 : 375 : set_dummy_rel_pathlist(rel);
425 : : }
426 [ + + ]: 295091 : else if (rte->inh)
427 : : {
428 : : /* It's an "append relation", process accordingly */
5161 429 : 13298 : set_append_rel_size(root, rel, rti, rte);
430 : : }
431 : : else
432 : : {
5500 433 [ + + + + : 281793 : switch (rel->rtekind)
+ + + +
- ]
434 : : {
435 : 230460 : case RTE_RELATION:
436 [ + + ]: 230460 : if (rte->relkind == RELKIND_FOREIGN_TABLE)
437 : : {
438 : : /* Foreign table */
5161 439 : 1241 : set_foreign_size(root, rel, rte);
440 : : }
3281 rhaas@postgresql.org 441 [ + + ]: 229219 : else if (rte->relkind == RELKIND_PARTITIONED_TABLE)
442 : : {
443 : : /*
444 : : * We could get here if asked to scan a partitioned table
445 : : * with ONLY. In that case we shouldn't scan any of the
446 : : * partitions, so mark it as a dummy rel.
447 : : */
448 : 20 : set_dummy_rel_pathlist(rel);
449 : : }
3957 simon@2ndQuadrant.co 450 [ + + ]: 229199 : else if (rte->tablesample != NULL)
451 : : {
452 : : /* Sampled relation */
453 : 153 : set_tablesample_rel_size(root, rel, rte);
454 : : }
455 : : else
456 : : {
457 : : /* Plain relation */
5161 tgl@sss.pgh.pa.us 458 : 229046 : set_plain_rel_size(root, rel, rte);
459 : : }
5500 460 : 230443 : break;
461 : 13450 : case RTE_SUBQUERY:
462 : :
463 : : /*
464 : : * Subqueries don't support making a choice between
465 : : * parameterized and unparameterized paths, so just go ahead
466 : : * and build their paths immediately.
467 : : */
468 : 13450 : set_subquery_pathlist(root, rel, rti, rte);
469 : 13450 : break;
470 : 27918 : case RTE_FUNCTION:
5161 471 : 27918 : set_function_size_estimates(root, rel);
5500 472 : 27918 : break;
3294 alvherre@alvh.no-ip. 473 : 311 : case RTE_TABLEFUNC:
474 : 311 : set_tablefunc_size_estimates(root, rel);
475 : 311 : break;
5500 tgl@sss.pgh.pa.us 476 : 4326 : case RTE_VALUES:
5161 477 : 4326 : set_values_size_estimates(root, rel);
5500 478 : 4326 : break;
479 : 2915 : case RTE_CTE:
480 : :
481 : : /*
482 : : * CTEs don't support making a choice between parameterized
483 : : * and unparameterized paths, so just go ahead and build their
484 : : * paths immediately.
485 : : */
486 [ + + ]: 2915 : if (rte->self_reference)
487 : 543 : set_worktable_pathlist(root, rel, rte);
488 : : else
489 : 2372 : set_cte_pathlist(root, rel, rte);
490 : 2915 : break;
3271 kgrittn@postgresql.o 491 : 241 : case RTE_NAMEDTUPLESTORE:
492 : : /* Might as well just build the path immediately */
493 : 241 : set_namedtuplestore_pathlist(root, rel, rte);
494 : 241 : break;
2603 tgl@sss.pgh.pa.us 495 : 2172 : case RTE_RESULT:
496 : : /* Might as well just build the path immediately */
497 : 2172 : set_result_pathlist(root, rel, rte);
498 : 2172 : break;
5500 tgl@sss.pgh.pa.us 499 :UBC 0 : default:
500 [ # # ]: 0 : elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
501 : : break;
502 : : }
503 : : }
504 : :
505 : : /*
506 : : * We insist that all non-dummy rels have a nonzero rowcount estimate.
507 : : */
3885 tgl@sss.pgh.pa.us 508 [ + + - + ]:CBC 295448 : Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
5161 509 : 295448 : }
510 : :
511 : : /*
512 : : * set_rel_pathlist
513 : : * Build access paths for a base relation
514 : : */
515 : : static void
516 : 295520 : set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
517 : : Index rti, RangeTblEntry *rte)
518 : : {
519 [ + + ]: 295520 : if (IS_DUMMY_REL(rel))
520 : : {
521 : : /* We already proved the relation empty, so nothing more to do */
522 : : }
523 [ + + ]: 294840 : else if (rte->inh)
524 : : {
525 : : /* It's an "append relation", process accordingly */
526 : 13147 : set_append_rel_pathlist(root, rel, rti, rte);
527 : : }
528 : : else
529 : : {
530 [ + + + + : 281693 : switch (rel->rtekind)
+ + + +
- ]
531 : : {
532 : 230423 : case RTE_RELATION:
533 [ + + ]: 230423 : if (rte->relkind == RELKIND_FOREIGN_TABLE)
534 : : {
535 : : /* Foreign table */
536 : 1239 : set_foreign_pathlist(root, rel, rte);
537 : : }
3957 simon@2ndQuadrant.co 538 [ + + ]: 229184 : else if (rte->tablesample != NULL)
539 : : {
540 : : /* Sampled relation */
541 : 153 : set_tablesample_rel_pathlist(root, rel, rte);
542 : : }
543 : : else
544 : : {
545 : : /* Plain relation */
5161 tgl@sss.pgh.pa.us 546 : 229031 : set_plain_rel_pathlist(root, rel, rte);
547 : : }
548 : 230423 : break;
549 : 13387 : case RTE_SUBQUERY:
550 : : /* Subquery --- fully handled during set_rel_size */
551 : 13387 : break;
552 : 27918 : case RTE_FUNCTION:
553 : : /* RangeFunction */
554 : 27918 : set_function_pathlist(root, rel, rte);
555 : 27918 : break;
3294 alvherre@alvh.no-ip. 556 : 311 : case RTE_TABLEFUNC:
557 : : /* Table Function */
558 : 311 : set_tablefunc_pathlist(root, rel, rte);
559 : 311 : break;
5161 tgl@sss.pgh.pa.us 560 : 4326 : case RTE_VALUES:
561 : : /* Values list */
562 : 4326 : set_values_pathlist(root, rel, rte);
563 : 4326 : break;
564 : 2915 : case RTE_CTE:
565 : : /* CTE reference --- fully handled during set_rel_size */
566 : 2915 : break;
3271 kgrittn@postgresql.o 567 : 241 : case RTE_NAMEDTUPLESTORE:
568 : : /* tuplestore reference --- fully handled during set_rel_size */
569 : 241 : break;
2603 tgl@sss.pgh.pa.us 570 : 2172 : case RTE_RESULT:
571 : : /* simple Result --- fully handled during set_rel_size */
572 : 2172 : break;
5161 tgl@sss.pgh.pa.us 573 :UBC 0 : default:
574 [ # # ]: 0 : elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
575 : : break;
576 : : }
577 : : }
578 : :
579 : : /*
580 : : * Allow a plugin to editorialize on the set of Paths for this base
581 : : * relation. It could add new paths (such as CustomPaths) by calling
582 : : * add_path(), or add_partial_path() if parallel aware. It could also
583 : : * delete or modify paths added by the core code.
584 : : */
2591 tgl@sss.pgh.pa.us 585 [ - + ]:CBC 295520 : if (set_rel_pathlist_hook)
2591 tgl@sss.pgh.pa.us 586 :UBC 0 : (*set_rel_pathlist_hook) (root, rel, rti, rte);
587 : :
588 : : /*
589 : : * If this is a baserel, we should normally consider gathering any partial
590 : : * paths we may have created for it. We have to do this after calling the
591 : : * set_rel_pathlist_hook, else it cannot add partial paths to be included
592 : : * here.
593 : : *
594 : : * However, if this is an inheritance child, skip it. Otherwise, we could
595 : : * end up with a very large number of gather nodes, each trying to grab
596 : : * its own pool of workers. Instead, we'll consider gathering partial
597 : : * paths for the parent appendrel.
598 : : *
599 : : * Also, if this is the topmost scan/join rel, we postpone gathering until
600 : : * the final scan/join targetlist is available (see grouping_planner).
601 : : */
2925 rhaas@postgresql.org 602 [ + + ]:CBC 295520 : if (rel->reloptkind == RELOPT_BASEREL &&
1140 tgl@sss.pgh.pa.us 603 [ + + ]: 264729 : !bms_equal(rel->relids, root->all_query_rels))
2168 tomas.vondra@postgre 604 : 137817 : generate_useful_gather_paths(root, rel, false);
605 : :
606 : : /* Now find the cheapest of the paths for this rel */
4132 tgl@sss.pgh.pa.us 607 : 295520 : set_cheapest(rel);
608 : :
609 : : /*
610 : : * If a grouped relation for this rel exists, build partial aggregation
611 : : * paths for it.
612 : : *
613 : : * Note that this can only happen after we've called set_cheapest() for
614 : : * this base rel, because we need its cheapest paths.
615 : : */
158 rguo@postgresql.org 616 :GNC 295520 : set_grouped_rel_pathlist(root, rel);
617 : :
618 : : #ifdef OPTIMIZER_DEBUG
619 : : pprint(rel);
620 : : #endif
9254 tgl@sss.pgh.pa.us 621 :CBC 295520 : }
622 : :
623 : : /*
624 : : * set_plain_rel_size
625 : : * Set size estimates for a plain relation (no subquery, no inheritance)
626 : : */
627 : : static void
5161 628 : 229046 : set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
629 : : {
630 : : /*
631 : : * Test any partial indexes of rel for applicability. We must do this
632 : : * first since partial unique indexes can affect size estimates.
633 : : */
3636 634 : 229046 : check_index_predicates(root, rel);
635 : :
636 : : /* Mark rel with estimated output rows, width, etc */
6903 637 : 229046 : set_baserel_size_estimates(root, rel);
5161 638 : 229031 : }
639 : :
640 : : /*
641 : : * If this relation could possibly be scanned from within a worker, then set
642 : : * its consider_parallel flag.
643 : : */
644 : : static void
3777 rhaas@postgresql.org 645 : 233536 : set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
646 : : RangeTblEntry *rte)
647 : : {
648 : : /*
649 : : * The flag has previously been initialized to false, so we can just
650 : : * return if it becomes clear that we can't safely set it.
651 : : */
3542 tgl@sss.pgh.pa.us 652 [ - + ]: 233536 : Assert(!rel->consider_parallel);
653 : :
654 : : /* Don't call this if parallelism is disallowed for the entire query. */
3777 rhaas@postgresql.org 655 [ - + ]: 233536 : Assert(root->glob->parallelModeOK);
656 : :
657 : : /* This should only be called for baserels and appendrel children. */
3268 658 [ + + - + ]: 233536 : Assert(IS_SIMPLE_REL(rel));
659 : :
660 : : /* Assorted checks based on rtekind. */
3777 661 [ + + - + : 233536 : switch (rte->rtekind)
+ + + + +
- - ]
662 : : {
663 : 200317 : case RTE_RELATION:
664 : :
665 : : /*
666 : : * Currently, parallel workers can't access the leader's temporary
667 : : * tables. We could possibly relax this if we wrote all of its
668 : : * local buffers at the start of the query and made no changes
669 : : * thereafter (maybe we could allow hint bit changes), and if we
670 : : * taught the workers to read them. Writing a large number of
671 : : * temporary buffers could be expensive, though, and we don't have
672 : : * the rest of the necessary infrastructure right now anyway. So
673 : : * for now, bail out if we see a temporary table.
674 : : */
675 [ + + ]: 200317 : if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
676 : 4545 : return;
677 : :
678 : : /*
679 : : * Table sampling can be pushed down to workers if the sample
680 : : * function and its arguments are safe.
681 : : */
682 [ + + ]: 195772 : if (rte->tablesample != NULL)
683 : : {
3393 tgl@sss.pgh.pa.us 684 : 165 : char proparallel = func_parallel(rte->tablesample->tsmhandler);
685 : :
3777 rhaas@postgresql.org 686 [ + + ]: 165 : if (proparallel != PROPARALLEL_SAFE)
687 : 18 : return;
3495 tgl@sss.pgh.pa.us 688 [ + + ]: 147 : if (!is_parallel_safe(root, (Node *) rte->tablesample->args))
3777 rhaas@postgresql.org 689 : 6 : return;
690 : : }
691 : :
692 : : /*
693 : : * Ask FDWs whether they can support performing a ForeignScan
694 : : * within a worker. Most often, the answer will be no. For
695 : : * example, if the nature of the FDW is such that it opens a TCP
696 : : * connection with a remote server, each parallel worker would end
697 : : * up with a separate connection, and these connections might not
698 : : * be appropriately coordinated between workers and the leader.
699 : : */
3670 700 [ + + ]: 195748 : if (rte->relkind == RELKIND_FOREIGN_TABLE)
701 : : {
702 [ - + ]: 786 : Assert(rel->fdwroutine);
703 [ + + ]: 786 : if (!rel->fdwroutine->IsForeignScanParallelSafe)
704 : 748 : return;
705 [ - + ]: 38 : if (!rel->fdwroutine->IsForeignScanParallelSafe(root, rel, rte))
3670 rhaas@postgresql.org 706 :UBC 0 : return;
707 : : }
708 : :
709 : : /*
710 : : * There are additional considerations for appendrels, which we'll
711 : : * deal with in set_append_rel_size and set_append_rel_pathlist.
712 : : * For now, just set consider_parallel based on the rel's own
713 : : * quals and targetlist.
714 : : */
3777 rhaas@postgresql.org 715 :CBC 195000 : break;
716 : :
717 : 11590 : case RTE_SUBQUERY:
718 : :
719 : : /*
720 : : * There's no intrinsic problem with scanning a subquery-in-FROM
721 : : * (as distinct from a SubPlan or InitPlan) in a parallel worker.
722 : : * If the subquery doesn't happen to have any parallel-safe paths,
723 : : * then flagging it as consider_parallel won't change anything,
724 : : * but that's true for plain tables, too. We must set
725 : : * consider_parallel based on the rel's own quals and targetlist,
726 : : * so that if a subquery path is parallel-safe but the quals and
727 : : * projection we're sticking onto it are not, we correctly mark
728 : : * the SubqueryScanPath as not parallel-safe. (Note that
729 : : * set_subquery_pathlist() might push some of these quals down
730 : : * into the subquery itself, but that doesn't change anything.)
731 : : *
732 : : * We can't push sub-select containing LIMIT/OFFSET to workers as
733 : : * there is no guarantee that the row order will be fully
734 : : * deterministic, and applying LIMIT/OFFSET will lead to
735 : : * inconsistent results at the top-level. (In some cases, where
736 : : * the result is ordered, we could relax this restriction. But it
737 : : * doesn't currently seem worth expending extra effort to do so.)
738 : : */
739 : : {
2739 akapila@postgresql.o 740 : 11590 : Query *subquery = castNode(Query, rte->subquery);
741 : :
742 [ + + ]: 11590 : if (limit_needed(subquery))
743 : 256 : return;
744 : : }
3542 tgl@sss.pgh.pa.us 745 : 11334 : break;
746 : :
3777 rhaas@postgresql.org 747 :UBC 0 : case RTE_JOIN:
748 : : /* Shouldn't happen; we're only considering baserels here. */
749 : 0 : Assert(false);
750 : : return;
751 : :
3777 rhaas@postgresql.org 752 :CBC 15409 : case RTE_FUNCTION:
753 : : /* Check for parallel-restricted functions. */
3495 tgl@sss.pgh.pa.us 754 [ + + ]: 15409 : if (!is_parallel_safe(root, (Node *) rte->functions))
3777 rhaas@postgresql.org 755 : 7065 : return;
756 : 8344 : break;
757 : :
3294 alvherre@alvh.no-ip. 758 : 311 : case RTE_TABLEFUNC:
759 : : /* not parallel safe */
760 : 311 : return;
761 : :
3777 rhaas@postgresql.org 762 : 1443 : case RTE_VALUES:
763 : : /* Check for parallel-restricted functions. */
3495 tgl@sss.pgh.pa.us 764 [ + + ]: 1443 : if (!is_parallel_safe(root, (Node *) rte->values_lists))
765 : 6 : return;
3777 rhaas@postgresql.org 766 : 1437 : break;
767 : :
768 : 2293 : case RTE_CTE:
769 : :
770 : : /*
771 : : * CTE tuplestores aren't shared among parallel workers, so we
772 : : * force all CTE scans to happen in the leader. Also, populating
773 : : * the CTE would require executing a subplan that's not available
774 : : * in the worker, might be parallel-restricted, and must get
775 : : * executed only once.
776 : : */
777 : 2293 : return;
778 : :
3271 kgrittn@postgresql.o 779 : 227 : case RTE_NAMEDTUPLESTORE:
780 : :
781 : : /*
782 : : * tuplestore cannot be shared, at least without more
783 : : * infrastructure to support that.
784 : : */
785 : 227 : return;
786 : :
2603 tgl@sss.pgh.pa.us 787 : 1946 : case RTE_RESULT:
788 : : /* RESULT RTEs, in themselves, are no problem. */
789 : 1946 : break;
551 rguo@postgresql.org 790 :UBC 0 : case RTE_GROUP:
791 : : /* Shouldn't happen; we're only considering baserels here. */
792 : 0 : Assert(false);
793 : : return;
794 : : }
795 : :
796 : : /*
797 : : * If there's anything in baserestrictinfo that's parallel-restricted, we
798 : : * give up on parallelizing access to this relation. We could consider
799 : : * instead postponing application of the restricted quals until we're
800 : : * above all the parallelism in the plan tree, but it's not clear that
801 : : * that would be a win in very many cases, and it might be tricky to make
802 : : * outer join clauses work correctly. It would likely break equivalence
803 : : * classes, too.
804 : : */
3495 tgl@sss.pgh.pa.us 805 [ + + ]:CBC 218061 : if (!is_parallel_safe(root, (Node *) rel->baserestrictinfo))
3777 rhaas@postgresql.org 806 : 15103 : return;
807 : :
808 : : /*
809 : : * Likewise, if the relation's outputs are not parallel-safe, give up.
810 : : * (Usually, they're just Vars, but sometimes they're not.)
811 : : */
3495 tgl@sss.pgh.pa.us 812 [ + + ]: 202958 : if (!is_parallel_safe(root, (Node *) rel->reltarget->exprs))
3566 rhaas@postgresql.org 813 : 9 : return;
814 : :
815 : : /* We have a winner. */
3777 816 : 202949 : rel->consider_parallel = true;
817 : : }
818 : :
819 : : /*
820 : : * set_plain_rel_pathlist
821 : : * Build access paths for a plain relation (no subquery, no inheritance)
822 : : */
823 : : static void
5161 tgl@sss.pgh.pa.us 824 : 229031 : set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
825 : : {
826 : : Relids required_outer;
827 : :
828 : : /*
829 : : * We don't support pushing join clauses into the quals of a seqscan, but
830 : : * it could still have required parameterization due to LATERAL refs in
831 : : * its tlist.
832 : : */
4949 833 : 229031 : required_outer = rel->lateral_relids;
834 : :
835 : : /*
836 : : * Consider TID scans.
837 : : *
838 : : * If create_tidscan_paths returns true, then a TID scan path is forced.
839 : : * This happens when rel->baserestrictinfo contains CurrentOfExpr, because
840 : : * the executor can't handle any other type of path for such queries.
841 : : * Hence, we return without adding any other paths.
842 : : */
601 rhaas@postgresql.org 843 [ + + ]: 229031 : if (create_tidscan_paths(root, rel))
844 : 202 : return;
845 : :
846 : : /* Consider sequential scan */
3777 847 : 228829 : add_path(rel, create_seqscan_path(root, rel, required_outer, 0));
848 : :
849 : : /* If appropriate, consider parallel sequential scan */
3707 850 [ + + + + ]: 228829 : if (rel->consider_parallel && required_outer == NULL)
3606 tgl@sss.pgh.pa.us 851 : 172979 : create_plain_partial_paths(root, rel);
852 : :
853 : : /* Consider index scans */
7629 854 : 228829 : create_index_paths(root, rel);
855 : : }
856 : :
857 : : /*
858 : : * create_plain_partial_paths
859 : : * Build partial access paths for parallel scan of a plain relation
860 : : */
861 : : static void
3606 862 : 172979 : create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel)
863 : : {
864 : : int parallel_workers;
865 : :
2963 rhaas@postgresql.org 866 : 172979 : parallel_workers = compute_parallel_worker(rel, rel->pages, -1,
867 : : max_parallel_workers_per_gather);
868 : :
869 : : /* If any limit was set to zero, the user doesn't want a parallel scan. */
3566 tgl@sss.pgh.pa.us 870 [ + + ]: 172979 : if (parallel_workers <= 0)
871 : 158383 : return;
872 : :
873 : : /* Add an unordered partial path based on a parallel sequential scan. */
rhaas@postgresql.org 874 : 14596 : add_partial_path(rel, create_seqscan_path(root, rel, NULL, parallel_workers));
875 : : }
876 : :
877 : : /*
878 : : * set_tablesample_rel_size
879 : : * Set size estimates for a sampled relation
880 : : */
881 : : static void
3957 simon@2ndQuadrant.co 882 : 153 : set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
883 : : {
3886 tgl@sss.pgh.pa.us 884 : 153 : TableSampleClause *tsc = rte->tablesample;
885 : : TsmRoutine *tsm;
886 : : BlockNumber pages;
887 : : double tuples;
888 : :
889 : : /*
890 : : * Test any partial indexes of rel for applicability. We must do this
891 : : * first since partial unique indexes can affect size estimates.
892 : : */
3636 893 : 153 : check_index_predicates(root, rel);
894 : :
895 : : /*
896 : : * Call the sampling method's estimation function to estimate the number
897 : : * of pages it will read and the number of tuples it will return. (Note:
898 : : * we assume the function returns sane values.)
899 : : */
3886 900 : 153 : tsm = GetTsmRoutine(tsc->tsmhandler);
901 : 153 : tsm->SampleScanGetSampleSize(root, rel, tsc->args,
902 : : &pages, &tuples);
903 : :
904 : : /*
905 : : * For the moment, because we will only consider a SampleScan path for the
906 : : * rel, it's okay to just overwrite the pages and tuples estimates for the
907 : : * whole relation. If we ever consider multiple path types for sampled
908 : : * rels, we'll need more complication.
909 : : */
910 : 153 : rel->pages = pages;
911 : 153 : rel->tuples = tuples;
912 : :
913 : : /* Mark rel with estimated output rows, width, etc */
3957 simon@2ndQuadrant.co 914 : 153 : set_baserel_size_estimates(root, rel);
915 : 153 : }
916 : :
917 : : /*
918 : : * set_tablesample_rel_pathlist
919 : : * Build access paths for a sampled relation
920 : : */
921 : : static void
922 : 153 : set_tablesample_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
923 : : {
924 : : Relids required_outer;
925 : : Path *path;
926 : :
927 : : /*
928 : : * We don't support pushing join clauses into the quals of a samplescan,
929 : : * but it could still have required parameterization due to LATERAL refs
930 : : * in its tlist or TABLESAMPLE arguments.
931 : : */
932 : 153 : required_outer = rel->lateral_relids;
933 : :
934 : : /* Consider sampled scan */
935 : 153 : path = create_samplescan_path(root, rel, required_outer);
936 : :
937 : : /*
938 : : * If the sampling method does not support repeatable scans, we must avoid
939 : : * plans that would scan the rel multiple times. Ideally, we'd simply
940 : : * avoid putting the rel on the inside of a nestloop join; but adding such
941 : : * a consideration to the planner seems like a great deal of complication
942 : : * to support an uncommon usage of second-rate sampling methods. Instead,
943 : : * if there is a risk that the query might perform an unsafe join, just
944 : : * wrap the SampleScan in a Materialize node. We can check for joins by
945 : : * counting the membership of all_query_rels (note that this correctly
946 : : * counts inheritance trees as single rels). If we're inside a subquery,
947 : : * we can't easily check whether a join might occur in the outer query, so
948 : : * just assume one is possible.
949 : : *
950 : : * GetTsmRoutine is relatively expensive compared to the other tests here,
951 : : * so check repeatable_across_scans last, even though that's a bit odd.
952 : : */
3886 tgl@sss.pgh.pa.us 953 [ + + + + ]: 293 : if ((root->query_level > 1 ||
1140 954 : 140 : bms_membership(root->all_query_rels) != BMS_SINGLETON) &&
3189 955 [ + + ]: 49 : !(GetTsmRoutine(rte->tablesample->tsmhandler)->repeatable_across_scans))
956 : : {
46 rhaas@postgresql.org 957 :GNC 4 : path = (Path *) create_material_path(rel, path, true);
958 : : }
959 : :
3886 tgl@sss.pgh.pa.us 960 :CBC 153 : add_path(rel, path);
961 : :
962 : : /* For the moment, at least, there are no other paths to consider */
3957 simon@2ndQuadrant.co 963 : 153 : }
964 : :
965 : : /*
966 : : * set_foreign_size
967 : : * Set size estimates for a foreign table RTE
968 : : */
969 : : static void
5161 tgl@sss.pgh.pa.us 970 : 1241 : set_foreign_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
971 : : {
972 : : /* Mark rel with estimated output rows, width, etc */
973 : 1241 : set_foreign_size_estimates(root, rel);
974 : :
975 : : /* Let FDW adjust the size estimates, if it can */
5119 976 : 1241 : rel->fdwroutine->GetForeignRelSize(root, rel, rte->relid);
977 : :
978 : : /* ... but do not let it set the rows estimate to zero */
3885 979 : 1239 : rel->rows = clamp_row_est(rel->rows);
980 : :
981 : : /*
982 : : * Also, make sure rel->tuples is not insane relative to rel->rows.
983 : : * Notably, this ensures sanity if pg_class.reltuples contains -1 and the
984 : : * FDW doesn't do anything to replace that.
985 : : */
2081 986 [ + + ]: 1239 : rel->tuples = Max(rel->tuples, rel->rows);
5161 987 : 1239 : }
988 : :
989 : : /*
990 : : * set_foreign_pathlist
991 : : * Build access paths for a foreign table RTE
992 : : */
993 : : static void
994 : 1239 : set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
995 : : {
996 : : /* Call the FDW's GetForeignPaths function to generate path(s) */
5119 997 : 1239 : rel->fdwroutine->GetForeignPaths(root, rel, rte->relid);
5161 998 : 1239 : }
999 : :
1000 : : /*
1001 : : * set_append_rel_size
1002 : : * Set size estimates for a simple "append relation"
1003 : : *
1004 : : * The passed-in rel and RTE represent the entire append relation. The
1005 : : * relation's contents are computed by appending together the output of the
1006 : : * individual member relations. Note that in the non-partitioned inheritance
1007 : : * case, the first member relation is actually the same table as is mentioned
1008 : : * in the parent RTE ... but it has a different RTE and RelOptInfo. This is
1009 : : * a good thing because their outputs are not the same size.
1010 : : */
1011 : : static void
1012 : 13298 : set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
1013 : : Index rti, RangeTblEntry *rte)
1014 : : {
9065 1015 : 13298 : int parentRTindex = rti;
1016 : : bool has_live_children;
1017 : : double parent_tuples;
1018 : : double parent_rows;
1019 : : double parent_size;
1020 : : double *parent_attrsizes;
1021 : : int nattrs;
1022 : : ListCell *l;
1023 : :
1024 : : /* Guard against stack overflow due to overly deep inheritance tree. */
3104 rhaas@postgresql.org 1025 : 13298 : check_stack_depth();
1026 : :
3268 1027 [ + + - + ]: 13298 : Assert(IS_SIMPLE_REL(rel));
1028 : :
1029 : : /*
1030 : : * If this is a partitioned baserel, set the consider_partitionwise_join
1031 : : * flag; currently, we only consider partitionwise joins with the baserel
1032 : : * if its targetlist doesn't contain a whole-row Var.
1033 : : */
2753 efujita@postgresql.o 1034 [ + + ]: 13298 : if (enable_partitionwise_join &&
1035 [ + + ]: 2517 : rel->reloptkind == RELOPT_BASEREL &&
1036 [ + - ]: 2007 : rte->relkind == RELKIND_PARTITIONED_TABLE &&
1140 tgl@sss.pgh.pa.us 1037 [ + + ]: 2007 : bms_is_empty(rel->attr_needed[InvalidAttrNumber - rel->min_attr]))
2753 efujita@postgresql.o 1038 : 1969 : rel->consider_partitionwise_join = true;
1039 : :
1040 : : /*
1041 : : * Initialize to compute size estimates for whole append relation.
1042 : : *
1043 : : * We handle tuples estimates by setting "tuples" to the total number of
1044 : : * tuples accumulated from each live child, rather than using "rows".
1045 : : * Although an appendrel itself doesn't directly enforce any quals, its
1046 : : * child relations may. Therefore, setting "tuples" equal to "rows" for
1047 : : * an appendrel isn't always appropriate, and can lead to inaccurate cost
1048 : : * estimates. For example, when estimating the number of distinct values
1049 : : * from an appendrel, we would be unable to adjust the estimate based on
1050 : : * the restriction selectivity (see estimate_num_groups).
1051 : : *
1052 : : * We handle width estimates by weighting the widths of different child
1053 : : * rels proportionally to their number of rows. This is sensible because
1054 : : * the use of width estimates is mainly to compute the total relation
1055 : : * "footprint" if we have to sort or hash it. To do this, we sum the
1056 : : * total equivalent size (in "double" arithmetic) and then divide by the
1057 : : * total rowcount estimate. This is done separately for the total rel
1058 : : * width and each attribute.
1059 : : *
1060 : : * Note: if you consider changing this logic, beware that child rels could
1061 : : * have zero rows and/or width, if they were excluded by constraints.
1062 : : */
3885 tgl@sss.pgh.pa.us 1063 : 13298 : has_live_children = false;
391 rguo@postgresql.org 1064 : 13298 : parent_tuples = 0;
6470 tgl@sss.pgh.pa.us 1065 : 13298 : parent_rows = 0;
1066 : 13298 : parent_size = 0;
1067 : 13298 : nattrs = rel->max_attr - rel->min_attr + 1;
1068 : 13298 : parent_attrsizes = (double *) palloc0(nattrs * sizeof(double));
1069 : :
7348 1070 [ + + + + : 70176 : foreach(l, root->append_rel_list)
+ + ]
1071 : : {
1072 : 56879 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
1073 : : int childRTindex;
1074 : : RangeTblEntry *childRTE;
1075 : : RelOptInfo *childrel;
1076 : : List *childrinfos;
1077 : : ListCell *parentvars;
1078 : : ListCell *childvars;
1079 : : ListCell *lc;
1080 : :
1081 : : /* append_rel_list contains all append rels; ignore others */
1082 [ + + ]: 56879 : if (appinfo->parent_relid != parentRTindex)
1083 : 26228 : continue;
1084 : :
1085 : 30825 : childRTindex = appinfo->child_relid;
6903 1086 : 30825 : childRTE = root->simple_rte_array[childRTindex];
1087 : :
1088 : : /*
1089 : : * The child rel's RelOptInfo was already created during
1090 : : * add_other_rels_to_query.
1091 : : */
7117 1092 : 30825 : childrel = find_base_rel(root, childRTindex);
1093 [ - + ]: 30825 : Assert(childrel->reloptkind == RELOPT_OTHER_MEMBER_REL);
1094 : :
1095 : : /* We may have already proven the child to be dummy. */
2542 1096 [ + + ]: 30825 : if (IS_DUMMY_REL(childrel))
2599 alvherre@alvh.no-ip. 1097 : 9 : continue;
1098 : :
1099 : : /*
1100 : : * We have to copy the parent's targetlist and quals to the child,
1101 : : * with appropriate substitution of variables. However, the
1102 : : * baserestrictinfo quals were already copied/substituted when the
1103 : : * child RelOptInfo was built. So we don't need any additional setup
1104 : : * before applying constraint exclusion.
1105 : : */
6557 tgl@sss.pgh.pa.us 1106 [ + + ]: 30816 : if (relation_excluded_by_constraints(root, childrel, childRTE))
1107 : : {
1108 : : /*
1109 : : * This child need not be scanned, so we can omit it from the
1110 : : * appendrel.
1111 : : */
6868 1112 : 96 : set_dummy_rel_pathlist(childrel);
6903 1113 : 96 : continue;
1114 : : }
1115 : :
1116 : : /*
1117 : : * Constraint exclusion failed, so copy the parent's join quals and
1118 : : * targetlist to the child, with appropriate variable substitutions.
1119 : : *
1120 : : * We skip join quals that came from above outer joins that can null
1121 : : * this rel, since they would be of no value while generating paths
1122 : : * for the child. This saves some effort while processing the child
1123 : : * rel, and it also avoids an implementation restriction in
1124 : : * adjust_appendrel_attrs (it can't apply nullingrels to a non-Var).
1125 : : */
1099 1126 : 30720 : childrinfos = NIL;
1127 [ + + + + : 37320 : foreach(lc, rel->joininfo)
+ + ]
1128 : : {
1129 : 6600 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1130 : :
1131 [ + + ]: 6600 : if (!bms_overlap(rinfo->clause_relids, rel->nulling_relids))
1132 : 5439 : childrinfos = lappend(childrinfos,
1133 : 5439 : adjust_appendrel_attrs(root,
1134 : : (Node *) rinfo,
1135 : : 1, &appinfo));
1136 : : }
1137 : 30720 : childrel->joininfo = childrinfos;
1138 : :
1139 : : /*
1140 : : * Now for the child's targetlist.
1141 : : *
1142 : : * NB: the resulting childrel->reltarget->exprs may contain arbitrary
1143 : : * expressions, which otherwise would not occur in a rel's targetlist.
1144 : : * Code that might be looking at an appendrel child must cope with
1145 : : * such. (Normally, a rel's targetlist would only include Vars and
1146 : : * PlaceHolderVars.) XXX we do not bother to update the cost or width
1147 : : * fields of childrel->reltarget; not clear if that would be useful.
1148 : : */
2610 efujita@postgresql.o 1149 : 61440 : childrel->reltarget->exprs = (List *)
1150 : 30720 : adjust_appendrel_attrs(root,
1151 : 30720 : (Node *) rel->reltarget->exprs,
1152 : : 1, &appinfo);
1153 : :
1154 : : /*
1155 : : * We have to make child entries in the EquivalenceClass data
1156 : : * structures as well. This is needed either if the parent
1157 : : * participates in some eclass joins (because we will want to consider
1158 : : * inner-indexscan joins on the individual children) or if the parent
1159 : : * has useful pathkeys (because we should try to build MergeAppend
1160 : : * paths that produce those sort orderings).
1161 : : */
1162 [ + + + + ]: 30720 : if (rel->has_eclass_joins || has_useful_pathkeys(root, rel))
1163 : 19232 : add_child_rel_equivalences(root, appinfo, rel, childrel);
1164 : 30720 : childrel->has_eclass_joins = rel->has_eclass_joins;
1165 : :
1166 : : /*
1167 : : * Note: we could compute appropriate attr_needed data for the child's
1168 : : * variables, by transforming the parent's attr_needed through the
1169 : : * translated_vars mapping. However, currently there's no need
1170 : : * because attr_needed is only examined for base relations not
1171 : : * otherrels. So we just leave the child's attr_needed empty.
1172 : : */
1173 : :
1174 : : /*
1175 : : * If we consider partitionwise joins with the parent rel, do the same
1176 : : * for partitioned child rels.
1177 : : *
1178 : : * Note: here we abuse the consider_partitionwise_join flag by setting
1179 : : * it for child rels that are not themselves partitioned. We do so to
1180 : : * tell try_partitionwise_join() that the child rel is sufficiently
1181 : : * valid to be used as a per-partition input, even if it later gets
1182 : : * proven to be dummy. (It's not usable until we've set up the
1183 : : * reltarget and EC entries, which we just did.)
1184 : : */
1185 [ + + ]: 30720 : if (rel->consider_partitionwise_join)
2753 1186 : 6651 : childrel->consider_partitionwise_join = true;
1187 : :
1188 : : /*
1189 : : * If parallelism is allowable for this query in general, see whether
1190 : : * it's allowable for this childrel in particular. But if we've
1191 : : * already decided the appendrel is not parallel-safe as a whole,
1192 : : * there's no point in considering parallelism for this child. For
1193 : : * consistency, do this before calling set_rel_size() for the child.
1194 : : */
3542 tgl@sss.pgh.pa.us 1195 [ + + + + ]: 30720 : if (root->glob->parallelModeOK && rel->consider_parallel)
1196 : 23213 : set_rel_consider_parallel(root, childrel, childRTE);
1197 : :
1198 : : /*
1199 : : * Compute the child's size.
1200 : : */
5161 1201 : 30720 : set_rel_size(root, childrel, childRTindex, childRTE);
1202 : :
1203 : : /*
1204 : : * It is possible that constraint exclusion detected a contradiction
1205 : : * within a child subquery, even though we didn't prove one above. If
1206 : : * so, we can skip this child.
1207 : : */
1208 [ + + ]: 30719 : if (IS_DUMMY_REL(childrel))
5286 1209 : 69 : continue;
1210 : :
1211 : : /* We have at least one live child. */
3885 1212 : 30650 : has_live_children = true;
1213 : :
1214 : : /*
1215 : : * If any live child is not parallel-safe, treat the whole appendrel
1216 : : * as not parallel-safe. In future we might be able to generate plans
1217 : : * in which some children are farmed out to workers while others are
1218 : : * not; but we don't have that today, so it's a waste to consider
1219 : : * partial paths anywhere in the appendrel unless it's all safe.
1220 : : * (Child rels visited before this one will be unmarked in
1221 : : * set_append_rel_pathlist().)
1222 : : */
3542 1223 [ + + ]: 30650 : if (!childrel->consider_parallel)
1224 : 7865 : rel->consider_parallel = false;
1225 : :
1226 : : /*
1227 : : * Accumulate size information from each live child.
1228 : : */
3885 1229 [ - + ]: 30650 : Assert(childrel->rows > 0);
1230 : :
391 rguo@postgresql.org 1231 : 30650 : parent_tuples += childrel->tuples;
3885 tgl@sss.pgh.pa.us 1232 : 30650 : parent_rows += childrel->rows;
3653 1233 : 30650 : parent_size += childrel->reltarget->width * childrel->rows;
1234 : :
1235 : : /*
1236 : : * Accumulate per-column estimates too. We need not do anything for
1237 : : * PlaceHolderVars in the parent list. If child expression isn't a
1238 : : * Var, or we didn't record a width estimate for it, we have to fall
1239 : : * back on a datatype-based estimate.
1240 : : *
1241 : : * By construction, child's targetlist is 1-to-1 with parent's.
1242 : : */
1243 [ + + + + : 104109 : forboth(parentvars, rel->reltarget->exprs,
+ + + + +
+ + - +
+ ]
1244 : : childvars, childrel->reltarget->exprs)
1245 : : {
3885 1246 : 73459 : Var *parentvar = (Var *) lfirst(parentvars);
1247 : 73459 : Node *childvar = (Node *) lfirst(childvars);
1248 : :
1810 1249 [ + + + + ]: 73459 : if (IsA(parentvar, Var) && parentvar->varno == parentRTindex)
1250 : : {
3885 1251 : 66909 : int pndx = parentvar->varattno - rel->min_attr;
1252 : 66909 : int32 child_width = 0;
1253 : :
1254 [ + + ]: 66909 : if (IsA(childvar, Var) &&
1255 [ + + ]: 64396 : ((Var *) childvar)->varno == childrel->relid)
1256 : : {
1257 : 64351 : int cndx = ((Var *) childvar)->varattno - childrel->min_attr;
1258 : :
1259 : 64351 : child_width = childrel->attr_widths[cndx];
1260 : : }
1261 [ + + ]: 66909 : if (child_width <= 0)
1262 : 2558 : child_width = get_typavgwidth(exprType(childvar),
1263 : : exprTypmod(childvar));
1264 [ - + ]: 66909 : Assert(child_width > 0);
1265 : 66909 : parent_attrsizes[pndx] += child_width * childrel->rows;
1266 : : }
1267 : : }
1268 : : }
1269 : :
1270 [ + + ]: 13297 : if (has_live_children)
1271 : : {
1272 : : /*
1273 : : * Save the finished size estimates.
1274 : : */
1275 : : int i;
1276 : :
1277 [ - + ]: 13147 : Assert(parent_rows > 0);
391 rguo@postgresql.org 1278 : 13147 : rel->tuples = parent_tuples;
3885 tgl@sss.pgh.pa.us 1279 : 13147 : rel->rows = parent_rows;
3653 1280 : 13147 : rel->reltarget->width = rint(parent_size / parent_rows);
6470 1281 [ + + ]: 122299 : for (i = 0; i < nattrs; i++)
1282 : 109152 : rel->attr_widths[i] = rint(parent_attrsizes[i] / parent_rows);
1283 : :
1284 : : /*
1285 : : * Note that we leave rel->pages as zero; this is important to avoid
1286 : : * double-counting the appendrel tree in total_table_pages.
1287 : : */
1288 : : }
1289 : : else
1290 : : {
1291 : : /*
1292 : : * All children were excluded by constraints, so mark the whole
1293 : : * appendrel dummy. We must do this in this phase so that the rel's
1294 : : * dummy-ness is visible when we generate paths for other rels.
1295 : : */
3885 1296 : 150 : set_dummy_rel_pathlist(rel);
1297 : : }
1298 : :
6470 1299 : 13297 : pfree(parent_attrsizes);
5161 1300 : 13297 : }
1301 : :
1302 : : /*
1303 : : * set_append_rel_pathlist
1304 : : * Build access paths for an "append relation"
1305 : : */
1306 : : static void
1307 : 13147 : set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
1308 : : Index rti, RangeTblEntry *rte)
1309 : : {
1310 : 13147 : int parentRTindex = rti;
1311 : 13147 : List *live_childrels = NIL;
1312 : : ListCell *l;
1313 : :
1314 : : /*
1315 : : * Generate access paths for each member relation, and remember the
1316 : : * non-dummy children.
1317 : : */
1318 [ + - + + : 69818 : foreach(l, root->append_rel_list)
+ + ]
1319 : : {
1320 : 56671 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
1321 : : int childRTindex;
1322 : : RangeTblEntry *childRTE;
1323 : : RelOptInfo *childrel;
1324 : :
1325 : : /* append_rel_list contains all append rels; ignore others */
1326 [ + + ]: 56671 : if (appinfo->parent_relid != parentRTindex)
1327 : 25880 : continue;
1328 : :
1329 : : /* Re-locate the child RTE and RelOptInfo */
1330 : 30791 : childRTindex = appinfo->child_relid;
1331 : 30791 : childRTE = root->simple_rte_array[childRTindex];
1332 : 30791 : childrel = root->simple_rel_array[childRTindex];
1333 : :
1334 : : /*
1335 : : * If set_append_rel_size() decided the parent appendrel was
1336 : : * parallel-unsafe at some point after visiting this child rel, we
1337 : : * need to propagate the unsafety marking down to the child, so that
1338 : : * we don't generate useless partial paths for it.
1339 : : */
3542 1340 [ + + ]: 30791 : if (!rel->consider_parallel)
1341 : 7966 : childrel->consider_parallel = false;
1342 : :
1343 : : /*
1344 : : * Compute the child's access paths.
1345 : : */
5161 1346 : 30791 : set_rel_pathlist(root, childrel, childRTindex, childRTE);
1347 : :
1348 : : /*
1349 : : * If child is dummy, ignore it.
1350 : : */
1351 [ + + ]: 30791 : if (IS_DUMMY_REL(childrel))
1352 : 141 : continue;
1353 : :
1354 : : /*
1355 : : * Child is live, so add it to the live_childrels list for use below.
1356 : : */
4964 1357 : 30650 : live_childrels = lappend(live_childrels, childrel);
1358 : : }
1359 : :
1360 : : /* Add paths to the append relation. */
3288 rhaas@postgresql.org 1361 : 13147 : add_paths_to_append_rel(root, rel, live_childrels);
1362 : 13147 : }
1363 : :
1364 : : /*
1365 : : * set_grouped_rel_pathlist
1366 : : * If a grouped relation for the given 'rel' exists, build partial
1367 : : * aggregation paths for it.
1368 : : */
1369 : : static void
158 rguo@postgresql.org 1370 :GNC 295520 : set_grouped_rel_pathlist(PlannerInfo *root, RelOptInfo *rel)
1371 : : {
1372 : : RelOptInfo *grouped_rel;
1373 : :
1374 : : /*
1375 : : * If there are no aggregate expressions or grouping expressions, eager
1376 : : * aggregation is not possible.
1377 : : */
1378 [ + + ]: 295520 : if (root->agg_clause_list == NIL ||
1379 [ + + ]: 1666 : root->group_expr_list == NIL)
1380 : 293986 : return;
1381 : :
1382 : : /* Add paths to the grouped base relation if one exists. */
1383 : 1534 : grouped_rel = rel->grouped_rel;
1384 [ + + ]: 1534 : if (grouped_rel)
1385 : : {
1386 [ - + ]: 293 : Assert(IS_GROUPED_REL(grouped_rel));
1387 : :
1388 : 293 : generate_grouped_paths(root, grouped_rel, rel);
1389 : 293 : set_cheapest(grouped_rel);
1390 : : }
1391 : : }
1392 : :
1393 : :
1394 : : /*
1395 : : * add_paths_to_append_rel
1396 : : * Generate paths for the given append relation given the set of non-dummy
1397 : : * child rels.
1398 : : *
1399 : : * The function collects all parameterizations and orderings supported by the
1400 : : * non-dummy children. For every such parameterization or ordering, it creates
1401 : : * an append path collecting one path from each non-dummy child with given
1402 : : * parameterization or ordering. Similarly it collects partial paths from
1403 : : * non-dummy children to create partial append paths.
1404 : : */
1405 : : void
3288 rhaas@postgresql.org 1406 :CBC 23954 : add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
1407 : : List *live_childrels)
1408 : : {
33 rhaas@postgresql.org 1409 :GNC 23954 : AppendPathInput unparameterized = {0};
1410 : 23954 : AppendPathInput startup = {0};
1411 : 23954 : AppendPathInput partial_only = {0};
1412 : 23954 : AppendPathInput parallel_append = {0};
1413 : 23954 : bool unparameterized_valid = true;
1414 : 23954 : bool startup_valid = true;
1415 : 23954 : bool partial_only_valid = true;
1416 : 23954 : bool parallel_append_valid = true;
3288 rhaas@postgresql.org 1417 :CBC 23954 : List *all_child_pathkeys = NIL;
1418 : 23954 : List *all_child_outers = NIL;
1419 : : ListCell *l;
3022 1420 : 23954 : double partial_rows = -1;
1421 : :
1422 : : /* If appropriate, consider parallel append */
33 rhaas@postgresql.org 1423 [ + + + + ]:GNC 23954 : parallel_append_valid = enable_parallel_append && rel->consider_parallel;
1424 : :
1425 : : /*
1426 : : * For every non-dummy child, remember the cheapest path. Also, identify
1427 : : * all pathkeys (orderings) and parameterizations (required_outer sets)
1428 : : * available for the non-dummy member relations.
1429 : : */
3288 rhaas@postgresql.org 1430 [ + - + + :CBC 77614 : foreach(l, live_childrels)
+ + ]
1431 : : {
1432 : 53660 : RelOptInfo *childrel = lfirst(l);
1433 : : ListCell *lcp;
3022 1434 : 53660 : Path *cheapest_partial_path = NULL;
1435 : :
1436 : : /*
1437 : : * If child has an unparameterized cheapest-total path, add that to
1438 : : * the unparameterized Append path we are constructing for the parent.
1439 : : * If not, there's no workable unparameterized path.
1440 : : *
1441 : : * With partitionwise aggregates, the child rel's pathlist may be
1442 : : * empty, so don't assume that a path exists here.
1443 : : */
2915 1444 [ + - ]: 53660 : if (childrel->pathlist != NIL &&
1445 [ + + ]: 53660 : childrel->cheapest_total_path->param_info == NULL)
3022 1446 : 53282 : accumulate_append_subpath(childrel->cheapest_total_path,
1447 : : &unparameterized.subpaths, NULL, &unparameterized.child_append_relid_sets);
1448 : : else
33 rhaas@postgresql.org 1449 :GNC 378 : unparameterized_valid = false;
1450 : :
1451 : : /*
1452 : : * When the planner is considering cheap startup plans, we'll also
1453 : : * collect all the cheapest_startup_paths (if set) and build an
1454 : : * AppendPath containing those as subpaths.
1455 : : */
887 drowley@postgresql.o 1456 [ + + + + ]:CBC 53660 : if (rel->consider_startup && childrel->cheapest_startup_path != NULL)
1457 : 865 : {
1458 : : Path *cheapest_path;
1459 : :
1460 : : /*
1461 : : * With an indication of how many tuples the query should provide,
1462 : : * the optimizer tries to choose the path optimal for that
1463 : : * specific number of tuples.
1464 : : */
370 akorotkov@postgresql 1465 [ + - ]: 865 : if (root->tuple_fraction > 0.0)
1466 : : cheapest_path =
1467 : 865 : get_cheapest_fractional_path(childrel,
1468 : : root->tuple_fraction);
1469 : : else
370 akorotkov@postgresql 1470 :UBC 0 : cheapest_path = childrel->cheapest_startup_path;
1471 : :
1472 : : /* cheapest_startup_path must not be a parameterized path. */
370 akorotkov@postgresql 1473 [ - + ]:CBC 865 : Assert(cheapest_path->param_info == NULL);
1474 : 865 : accumulate_append_subpath(cheapest_path,
1475 : : &startup.subpaths,
1476 : : NULL,
1477 : : &startup.child_append_relid_sets);
1478 : : }
1479 : : else
33 rhaas@postgresql.org 1480 :GNC 52795 : startup_valid = false;
1481 : :
1482 : :
1483 : : /* Same idea, but for a partial plan. */
3707 rhaas@postgresql.org 1484 [ + + ]:CBC 53660 : if (childrel->partial_pathlist != NIL)
1485 : : {
3022 1486 : 32635 : cheapest_partial_path = linitial(childrel->partial_pathlist);
1487 : 32635 : accumulate_append_subpath(cheapest_partial_path,
1488 : : &partial_only.partial_subpaths, NULL,
1489 : : &partial_only.child_append_relid_sets);
1490 : : }
1491 : : else
33 rhaas@postgresql.org 1492 :GNC 21025 : partial_only_valid = false;
1493 : :
1494 : : /*
1495 : : * Same idea, but for a parallel append mixing partial and non-partial
1496 : : * paths.
1497 : : */
1498 [ + + ]: 53660 : if (parallel_append_valid)
1499 : : {
3022 rhaas@postgresql.org 1500 :CBC 40635 : Path *nppath = NULL;
1501 : :
1502 : : nppath =
1503 : 40635 : get_cheapest_parallel_safe_total_inner(childrel->pathlist);
1504 : :
1505 [ + + + + ]: 40635 : if (cheapest_partial_path == NULL && nppath == NULL)
1506 : : {
1507 : : /* Neither a partial nor a parallel-safe path? Forget it. */
33 rhaas@postgresql.org 1508 :GNC 283 : parallel_append_valid = false;
1509 : : }
3022 rhaas@postgresql.org 1510 [ + + + + ]:CBC 40352 : else if (nppath == NULL ||
1511 : 32410 : (cheapest_partial_path != NULL &&
1512 [ + + ]: 32410 : cheapest_partial_path->total_cost < nppath->total_cost))
1513 : : {
1514 : : /* Partial path is cheaper or the only option. */
1515 [ - + ]: 32340 : Assert(cheapest_partial_path != NULL);
1516 : 32340 : accumulate_append_subpath(cheapest_partial_path,
1517 : : ¶llel_append.partial_subpaths,
1518 : : ¶llel_append.subpaths,
1519 : : ¶llel_append.child_append_relid_sets);
1520 : : }
1521 : : else
1522 : : {
1523 : : /*
1524 : : * Either we've got only a non-partial path, or we think that
1525 : : * a single backend can execute the best non-partial path
1526 : : * faster than all the parallel backends working together can
1527 : : * execute the best partial path.
1528 : : *
1529 : : * It might make sense to be more aggressive here. Even if
1530 : : * the best non-partial path is more expensive than the best
1531 : : * partial path, it could still be better to choose the
1532 : : * non-partial path if there are several such paths that can
1533 : : * be given to different workers. For now, we don't try to
1534 : : * figure that out.
1535 : : */
1536 : 8012 : accumulate_append_subpath(nppath,
1537 : : ¶llel_append.subpaths,
1538 : : NULL,
1539 : : ¶llel_append.child_append_relid_sets);
1540 : : }
1541 : : }
1542 : :
1543 : : /*
1544 : : * Collect lists of all the available path orderings and
1545 : : * parameterizations for all the children. We use these as a
1546 : : * heuristic to indicate which sort orderings and parameterizations we
1547 : : * should build Append and MergeAppend paths for.
1548 : : */
5161 tgl@sss.pgh.pa.us 1549 [ + - + + : 126200 : foreach(lcp, childrel->pathlist)
+ + ]
1550 : : {
1551 : 72540 : Path *childpath = (Path *) lfirst(lcp);
1552 : 72540 : List *childkeys = childpath->pathkeys;
5078 1553 [ + + ]: 72540 : Relids childouter = PATH_REQ_OUTER(childpath);
1554 : :
1555 : : /* Unsorted paths don't contribute to pathkey list */
5161 1556 [ + + ]: 72540 : if (childkeys != NIL)
1557 : : {
1558 : : ListCell *lpk;
1559 : 18713 : bool found = false;
1560 : :
1561 : : /* Have we already seen this ordering? */
1562 [ + + + + : 18828 : foreach(lpk, all_child_pathkeys)
+ + ]
1563 : : {
1564 : 12680 : List *existing_pathkeys = (List *) lfirst(lpk);
1565 : :
1566 [ + + ]: 12680 : if (compare_pathkeys(existing_pathkeys,
1567 : : childkeys) == PATHKEYS_EQUAL)
1568 : : {
1569 : 12565 : found = true;
1570 : 12565 : break;
1571 : : }
1572 : : }
1573 [ + + ]: 18713 : if (!found)
1574 : : {
1575 : : /* No, so add it to all_child_pathkeys */
1576 : 6148 : all_child_pathkeys = lappend(all_child_pathkeys,
1577 : : childkeys);
1578 : : }
1579 : : }
1580 : :
1581 : : /* Unparameterized paths don't contribute to param-set list */
1582 [ + + ]: 72540 : if (childouter)
1583 : : {
1584 : : ListCell *lco;
1585 : 3429 : bool found = false;
1586 : :
1587 : : /* Have we already seen this param set? */
1588 [ + + + + : 3843 : foreach(lco, all_child_outers)
+ + ]
1589 : : {
5026 bruce@momjian.us 1590 : 2540 : Relids existing_outers = (Relids) lfirst(lco);
1591 : :
5161 tgl@sss.pgh.pa.us 1592 [ + + ]: 2540 : if (bms_equal(existing_outers, childouter))
1593 : : {
1594 : 2126 : found = true;
1595 : 2126 : break;
1596 : : }
1597 : : }
1598 [ + + ]: 3429 : if (!found)
1599 : : {
1600 : : /* No, so add it to all_child_outers */
1601 : 1303 : all_child_outers = lappend(all_child_outers,
1602 : : childouter);
1603 : : }
1604 : : }
1605 : : }
1606 : : }
1607 : :
1608 : : /*
1609 : : * If we found unparameterized paths for all children, build an unordered,
1610 : : * unparameterized Append path for the rel. (Note: this is correct even
1611 : : * if we have zero or one live subpath due to constraint exclusion.)
1612 : : */
33 rhaas@postgresql.org 1613 [ + + ]:GNC 23954 : if (unparameterized_valid)
1614 : 23792 : add_path(rel, (Path *) create_append_path(root, rel, unparameterized,
1615 : : NIL, NULL, 0, false,
1616 : : -1));
1617 : :
1618 : : /* build an AppendPath for the cheap startup paths, if valid */
1619 [ + + ]: 23954 : if (startup_valid)
1620 : 350 : add_path(rel, (Path *) create_append_path(root, rel, startup,
1621 : : NIL, NULL, 0, false, -1));
1622 : :
1623 : : /*
1624 : : * Consider an append of unordered, unparameterized partial paths. Make
1625 : : * it parallel-aware if possible.
1626 : : */
1627 [ + + + - ]: 23954 : if (partial_only_valid && partial_only.partial_subpaths != NIL)
1628 : : {
1629 : : AppendPath *appendpath;
1630 : : ListCell *lc;
3566 rhaas@postgresql.org 1631 :CBC 14194 : int parallel_workers = 0;
1632 : :
1633 : : /* Find the highest number of workers requested for any subpath. */
33 rhaas@postgresql.org 1634 [ + - + + :GNC 49054 : foreach(lc, partial_only.partial_subpaths)
+ + ]
1635 : : {
3707 rhaas@postgresql.org 1636 :CBC 34860 : Path *path = lfirst(lc);
1637 : :
3566 1638 : 34860 : parallel_workers = Max(parallel_workers, path->parallel_workers);
1639 : : }
1640 [ - + ]: 14194 : Assert(parallel_workers > 0);
1641 : :
1642 : : /*
1643 : : * If the use of parallel append is permitted, always request at least
1644 : : * log2(# of children) workers. We assume it can be useful to have
1645 : : * extra workers in this case because they will be spread out across
1646 : : * the children. The precise formula is just a guess, but we don't
1647 : : * want to end up with a radically different answer for a table with N
1648 : : * partitions vs. an unpartitioned table with the same data, so the
1649 : : * use of some kind of log-scaling here seems to make some sense.
1650 : : */
3022 1651 [ + + ]: 14194 : if (enable_parallel_append)
1652 : : {
1653 [ + + ]: 14170 : parallel_workers = Max(parallel_workers,
1654 : : pg_leftmost_one_pos32(list_length(live_childrels)) + 1);
1655 : 14170 : parallel_workers = Min(parallel_workers,
1656 : : max_parallel_workers_per_gather);
1657 : : }
1658 [ - + ]: 14194 : Assert(parallel_workers > 0);
1659 : :
1660 : : /* Generate a partial append path. */
33 rhaas@postgresql.org 1661 :GNC 14194 : appendpath = create_append_path(root, rel, partial_only,
1662 : : NIL, NULL, parallel_workers,
1663 : : enable_parallel_append,
1664 : : -1);
1665 : :
1666 : : /*
1667 : : * Make sure any subsequent partial paths use the same row count
1668 : : * estimate.
1669 : : */
3022 rhaas@postgresql.org 1670 :CBC 14194 : partial_rows = appendpath->path.rows;
1671 : :
1672 : : /* Add the path. */
1673 : 14194 : add_partial_path(rel, (Path *) appendpath);
1674 : : }
1675 : :
1676 : : /*
1677 : : * Consider a parallel-aware append using a mix of partial and non-partial
1678 : : * paths. (This only makes sense if there's at least one child which has
1679 : : * a non-partial path that is substantially cheaper than any partial path;
1680 : : * otherwise, we should use the append path added in the previous step.)
1681 : : */
33 rhaas@postgresql.org 1682 [ + + + + ]:GNC 23954 : if (parallel_append_valid && parallel_append.subpaths != NIL)
1683 : : {
1684 : : AppendPath *appendpath;
1685 : : ListCell *lc;
3022 rhaas@postgresql.org 1686 :CBC 2614 : int parallel_workers = 0;
1687 : :
1688 : : /*
1689 : : * Find the highest number of workers requested for any partial
1690 : : * subpath.
1691 : : */
33 rhaas@postgresql.org 1692 [ + + + + :GNC 3065 : foreach(lc, parallel_append.partial_subpaths)
+ + ]
1693 : : {
3022 rhaas@postgresql.org 1694 :CBC 451 : Path *path = lfirst(lc);
1695 : :
1696 : 451 : parallel_workers = Max(parallel_workers, path->parallel_workers);
1697 : : }
1698 : :
1699 : : /*
1700 : : * Same formula here as above. It's even more important in this
1701 : : * instance because the non-partial paths won't contribute anything to
1702 : : * the planned number of parallel workers.
1703 : : */
1704 [ + - ]: 2614 : parallel_workers = Max(parallel_workers,
1705 : : pg_leftmost_one_pos32(list_length(live_childrels)) + 1);
1706 : 2614 : parallel_workers = Min(parallel_workers,
1707 : : max_parallel_workers_per_gather);
1708 [ - + ]: 2614 : Assert(parallel_workers > 0);
1709 : :
33 rhaas@postgresql.org 1710 :GNC 2614 : appendpath = create_append_path(root, rel, parallel_append,
1711 : : NIL, NULL, parallel_workers, true,
1712 : : partial_rows);
3707 rhaas@postgresql.org 1713 :CBC 2614 : add_partial_path(rel, (Path *) appendpath);
1714 : : }
1715 : :
1716 : : /*
1717 : : * Also build unparameterized ordered append paths based on the collected
1718 : : * list of child pathkeys.
1719 : : */
33 rhaas@postgresql.org 1720 [ + + ]:GNC 23954 : if (unparameterized_valid)
2536 tgl@sss.pgh.pa.us 1721 :CBC 23792 : generate_orderedappend_paths(root, rel, live_childrels,
1722 : : all_child_pathkeys);
1723 : :
1724 : : /*
1725 : : * Build Append paths for each parameterization seen among the child rels.
1726 : : * (This may look pretty expensive, but in most cases of practical
1727 : : * interest, the child rels will expose mostly the same parameterizations,
1728 : : * so that not that many cases actually get considered here.)
1729 : : *
1730 : : * The Append node itself cannot enforce quals, so all qual checking must
1731 : : * be done in the child paths. This means that to have a parameterized
1732 : : * Append path, we must have the exact same parameterization for each
1733 : : * child path; otherwise some children might be failing to check the
1734 : : * moved-down quals. To make them match up, we can try to increase the
1735 : : * parameterization of lesser-parameterized paths.
1736 : : */
5161 1737 [ + + + + : 25257 : foreach(l, all_child_outers)
+ + ]
1738 : : {
5026 bruce@momjian.us 1739 : 1303 : Relids required_outer = (Relids) lfirst(l);
1740 : : ListCell *lcr;
33 rhaas@postgresql.org 1741 :GNC 1303 : AppendPathInput parameterized = {0};
1742 : 1303 : bool parameterized_valid = true;
1743 : :
1744 : : /* Select the child paths for an Append with this parameterization */
5161 tgl@sss.pgh.pa.us 1745 [ + - + + :CBC 4780 : foreach(lcr, live_childrels)
+ + ]
1746 : : {
1747 : 3483 : RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
1748 : : Path *subpath;
1749 : :
2915 rhaas@postgresql.org 1750 [ - + ]: 3483 : if (childrel->pathlist == NIL)
1751 : : {
1752 : : /* failed to make a suitable path for this child */
33 rhaas@postgresql.org 1753 :UNC 0 : parameterized_valid = false;
2915 rhaas@postgresql.org 1754 :UBC 0 : break;
1755 : : }
1756 : :
4634 tgl@sss.pgh.pa.us 1757 :CBC 3483 : subpath = get_cheapest_parameterized_child_path(root,
1758 : : childrel,
1759 : : required_outer);
1760 [ + + ]: 3483 : if (subpath == NULL)
1761 : : {
1762 : : /* failed to make a suitable path for this child */
33 rhaas@postgresql.org 1763 :GNC 6 : parameterized_valid = false;
4634 tgl@sss.pgh.pa.us 1764 :CBC 6 : break;
1765 : : }
33 rhaas@postgresql.org 1766 :GNC 3477 : accumulate_append_subpath(subpath, ¶meterized.subpaths, NULL,
1767 : : ¶meterized.child_append_relid_sets);
1768 : : }
1769 : :
1770 [ + + ]: 1303 : if (parameterized_valid)
5078 tgl@sss.pgh.pa.us 1771 :CBC 1297 : add_path(rel, (Path *)
33 rhaas@postgresql.org 1772 :GNC 1297 : create_append_path(root, rel, parameterized,
1773 : : NIL, required_outer, 0, false,
1774 : : -1));
1775 : : }
1776 : :
1777 : : /*
1778 : : * When there is only a single child relation, the Append path can inherit
1779 : : * any ordering available for the child rel's path, so that it's useful to
1780 : : * consider ordered partial paths. Above we only considered the cheapest
1781 : : * partial path for each child, but let's also make paths using any
1782 : : * partial paths that have pathkeys.
1783 : : */
2547 tgl@sss.pgh.pa.us 1784 [ + + ]:CBC 23954 : if (list_length(live_childrels) == 1)
1785 : : {
1786 : 7394 : RelOptInfo *childrel = (RelOptInfo *) linitial(live_childrels);
1787 : :
1788 : : /* skip the cheapest partial path, since we already used that above */
1959 drowley@postgresql.o 1789 [ + + + + : 7502 : for_each_from(l, childrel->partial_pathlist, 1)
+ + ]
1790 : : {
2547 tgl@sss.pgh.pa.us 1791 : 108 : Path *path = (Path *) lfirst(l);
1792 : : AppendPath *appendpath;
33 rhaas@postgresql.org 1793 :GNC 108 : AppendPathInput append = {0};
1794 : :
1795 : : /* skip paths with no pathkeys. */
1959 drowley@postgresql.o 1796 [ - + ]:CBC 108 : if (path->pathkeys == NIL)
2547 tgl@sss.pgh.pa.us 1797 :UBC 0 : continue;
1798 : :
33 rhaas@postgresql.org 1799 :GNC 108 : append.partial_subpaths = list_make1(path);
1800 : 108 : appendpath = create_append_path(root, rel, append, NIL, NULL,
1801 : : path->parallel_workers, true,
1802 : : partial_rows);
2547 tgl@sss.pgh.pa.us 1803 :CBC 108 : add_partial_path(rel, (Path *) appendpath);
1804 : : }
1805 : : }
5161 1806 : 23954 : }
1807 : :
1808 : : /*
1809 : : * generate_orderedappend_paths
1810 : : * Generate ordered append paths for an append relation
1811 : : *
1812 : : * Usually we generate MergeAppend paths here, but there are some special
1813 : : * cases where we can generate simple Append paths, because the subpaths
1814 : : * can provide tuples in the required order already.
1815 : : *
1816 : : * We generate a path for each ordering (pathkey list) appearing in
1817 : : * all_child_pathkeys.
1818 : : *
1819 : : * We consider the cheapest-startup and cheapest-total cases, and also the
1820 : : * cheapest-fractional case when not all tuples need to be retrieved. For each
1821 : : * interesting ordering, we collect all the cheapest startup subpaths, all the
1822 : : * cheapest total paths, and, if applicable, all the cheapest fractional paths,
1823 : : * and build a suitable path for each case.
1824 : : *
1825 : : * We don't currently generate any parameterized ordered paths here. While
1826 : : * it would not take much more code here to do so, it's very unclear that it
1827 : : * is worth the planning cycles to investigate such paths: there's little
1828 : : * use for an ordered path on the inside of a nestloop. In fact, it's likely
1829 : : * that the current coding of add_path would reject such paths out of hand,
1830 : : * because add_path gives no credit for sort ordering of parameterized paths,
1831 : : * and a parameterized MergeAppend is going to be more expensive than the
1832 : : * corresponding parameterized Append path. If we ever try harder to support
1833 : : * parameterized mergejoin plans, it might be worth adding support for
1834 : : * parameterized paths here to feed such joins. (See notes in
1835 : : * optimizer/README for why that might not ever happen, though.)
1836 : : */
1837 : : static void
2536 1838 : 23792 : generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel,
1839 : : List *live_childrels,
1840 : : List *all_child_pathkeys)
1841 : : {
1842 : : ListCell *lcp;
1843 : 23792 : List *partition_pathkeys = NIL;
1844 : 23792 : List *partition_pathkeys_desc = NIL;
1845 : 23792 : bool partition_pathkeys_partial = true;
1846 : 23792 : bool partition_pathkeys_desc_partial = true;
1847 : :
1848 : : /*
1849 : : * Some partitioned table setups may allow us to use an Append node
1850 : : * instead of a MergeAppend. This is possible in cases such as RANGE
1851 : : * partitioned tables where it's guaranteed that an earlier partition must
1852 : : * contain rows which come earlier in the sort order. To detect whether
1853 : : * this is relevant, build pathkey descriptions of the partition ordering,
1854 : : * for both forward and reverse scans.
1855 : : */
1856 [ + + + + : 38473 : if (rel->part_scheme != NULL && IS_SIMPLE_REL(rel) &&
+ + + + ]
1685 drowley@postgresql.o 1857 : 14681 : partitions_are_ordered(rel->boundinfo, rel->live_parts))
1858 : : {
2536 tgl@sss.pgh.pa.us 1859 : 12225 : partition_pathkeys = build_partition_pathkeys(root, rel,
1860 : : ForwardScanDirection,
1861 : : &partition_pathkeys_partial);
1862 : :
1863 : 12225 : partition_pathkeys_desc = build_partition_pathkeys(root, rel,
1864 : : BackwardScanDirection,
1865 : : &partition_pathkeys_desc_partial);
1866 : :
1867 : : /*
1868 : : * You might think we should truncate_useless_pathkeys here, but
1869 : : * allowing partition keys which are a subset of the query's pathkeys
1870 : : * can often be useful. For example, consider a table partitioned by
1871 : : * RANGE (a, b), and a query with ORDER BY a, b, c. If we have child
1872 : : * paths that can produce the a, b, c ordering (perhaps via indexes on
1873 : : * (a, b, c)) then it works to consider the appendrel output as
1874 : : * ordered by a, b, c.
1875 : : */
1876 : : }
1877 : :
1878 : : /* Now consider each interesting sort ordering */
5161 1879 [ + + + + : 29910 : foreach(lcp, all_child_pathkeys)
+ + ]
1880 : : {
1881 : 6118 : List *pathkeys = (List *) lfirst(lcp);
33 rhaas@postgresql.org 1882 :GNC 6118 : AppendPathInput startup = {0};
1883 : 6118 : AppendPathInput total = {0};
1884 : 6118 : AppendPathInput fractional = {0};
5453 bruce@momjian.us 1885 :CBC 6118 : bool startup_neq_total = false;
130 rguo@postgresql.org 1886 :GNC 6118 : bool fraction_neq_total = false;
1887 : : bool match_partition_order;
1888 : : bool match_partition_order_desc;
1889 : : int end_index;
1890 : : int first_index;
1891 : : int direction;
1892 : :
1893 : : /*
1894 : : * Determine if this sort ordering matches any partition pathkeys we
1895 : : * have, for both ascending and descending partition order. If the
1896 : : * partition pathkeys happen to be contained in pathkeys then it still
1897 : : * works, as described above, providing that the partition pathkeys
1898 : : * are complete and not just a prefix of the partition keys. (In such
1899 : : * cases we'll be relying on the child paths to have sorted the
1900 : : * lower-order columns of the required pathkeys.)
1901 : : */
2536 tgl@sss.pgh.pa.us 1902 :CBC 6118 : match_partition_order =
1903 [ + + ]: 11058 : pathkeys_contained_in(pathkeys, partition_pathkeys) ||
1904 [ + + + + ]: 5044 : (!partition_pathkeys_partial &&
1905 : 104 : pathkeys_contained_in(partition_pathkeys, pathkeys));
1906 : :
1907 [ + + + + ]: 15872 : match_partition_order_desc = !match_partition_order &&
1908 : 4886 : (pathkeys_contained_in(pathkeys, partition_pathkeys_desc) ||
1909 [ + + + + ]: 4900 : (!partition_pathkeys_desc_partial &&
1910 : 32 : pathkeys_contained_in(partition_pathkeys_desc, pathkeys)));
1911 : :
1912 : : /*
1913 : : * When the required pathkeys match the reverse of the partition
1914 : : * order, we must build the list of paths in reverse starting with the
1915 : : * last matching partition first. We can get away without making any
1916 : : * special cases for this in the loop below by just looping backward
1917 : : * over the child relations in this case.
1918 : : */
1119 drowley@postgresql.o 1919 [ + + ]: 6118 : if (match_partition_order_desc)
1920 : : {
1921 : : /* loop backward */
1922 : 24 : first_index = list_length(live_childrels) - 1;
1923 : 24 : end_index = -1;
1924 : 24 : direction = -1;
1925 : :
1926 : : /*
1927 : : * Set this to true to save us having to check for
1928 : : * match_partition_order_desc in the loop below.
1929 : : */
1930 : 24 : match_partition_order = true;
1931 : : }
1932 : : else
1933 : : {
1934 : : /* for all other case, loop forward */
1935 : 6094 : first_index = 0;
1936 : 6094 : end_index = list_length(live_childrels);
1937 : 6094 : direction = 1;
1938 : : }
1939 : :
1940 : : /* Select the child paths for this ordering... */
1941 [ + + ]: 21972 : for (int i = first_index; i != end_index; i += direction)
1942 : : {
1943 : 15854 : RelOptInfo *childrel = list_nth_node(RelOptInfo, live_childrels, i);
1944 : : Path *cheapest_startup,
1945 : : *cheapest_total,
1523 tomas.vondra@postgre 1946 : 15854 : *cheapest_fractional = NULL;
1947 : :
1948 : : /* Locate the right paths, if they are available. */
1949 : : cheapest_startup =
5631 tgl@sss.pgh.pa.us 1950 : 15854 : get_cheapest_path_for_pathkeys(childrel->pathlist,
1951 : : pathkeys,
1952 : : NULL,
1953 : : STARTUP_COST,
1954 : : false);
1955 : : cheapest_total =
1956 : 15854 : get_cheapest_path_for_pathkeys(childrel->pathlist,
1957 : : pathkeys,
1958 : : NULL,
1959 : : TOTAL_COST,
1960 : : false);
1961 : :
1962 : : /*
1963 : : * If we can't find any paths with the right order just use the
1964 : : * cheapest-total path; we'll have to sort it later.
1965 : : */
5161 1966 [ + + - + ]: 15854 : if (cheapest_startup == NULL || cheapest_total == NULL)
1967 : : {
5078 1968 : 170 : cheapest_startup = cheapest_total =
1969 : : childrel->cheapest_total_path;
1970 : : /* Assert we do have an unparameterized path for this child */
4964 1971 [ - + ]: 170 : Assert(cheapest_total->param_info == NULL);
1972 : : }
1973 : :
1974 : : /*
1975 : : * When building a fractional path, determine a cheapest
1976 : : * fractional path for each child relation too. Looking at startup
1977 : : * and total costs is not enough, because the cheapest fractional
1978 : : * path may be dominated by two separate paths (one for startup,
1979 : : * one for total).
1980 : : *
1981 : : * When needed (building fractional path), determine the cheapest
1982 : : * fractional path too.
1983 : : */
1523 tomas.vondra@postgre 1984 [ + + ]: 15854 : if (root->tuple_fraction > 0)
1985 : : {
301 akorotkov@postgresql 1986 : 448 : double path_fraction = root->tuple_fraction;
1987 : :
1988 : : /*
1989 : : * We should not have a dummy child relation here. However,
1990 : : * we cannot use childrel->rows to compute the tuple fraction,
1991 : : * as childrel can be an upper relation with an unset row
1992 : : * estimate. Instead, we use the row estimate from the
1993 : : * cheapest_total path, which should already have been forced
1994 : : * to a sane value.
1995 : : */
130 rguo@postgresql.org 1996 [ - + ]: 448 : Assert(cheapest_total->rows > 0);
1997 : :
1998 : : /* Convert absolute limit to a path fraction */
301 akorotkov@postgresql 1999 [ + - ]: 448 : if (path_fraction >= 1.0)
130 rguo@postgresql.org 2000 : 448 : path_fraction /= cheapest_total->rows;
2001 : :
2002 : : cheapest_fractional =
1523 tomas.vondra@postgre 2003 : 448 : get_cheapest_fractional_path_for_pathkeys(childrel->pathlist,
2004 : : pathkeys,
2005 : : NULL,
2006 : : path_fraction);
2007 : :
2008 : : /*
2009 : : * If we found no path with matching pathkeys, use the
2010 : : * cheapest total path instead.
2011 : : *
2012 : : * XXX We might consider partially sorted paths too (with an
2013 : : * incremental sort on top). But we'd have to build all the
2014 : : * incremental paths, do the costing etc.
2015 : : *
2016 : : * Also, notice whether we actually have different paths for
2017 : : * the "fractional" and "total" cases. This helps avoid
2018 : : * generating two identical ordered append paths.
2019 : : */
130 rguo@postgresql.org 2020 [ + + ]:GNC 448 : if (cheapest_fractional == NULL)
1523 tomas.vondra@postgre 2021 :CBC 22 : cheapest_fractional = cheapest_total;
130 rguo@postgresql.org 2022 [ - + ]:GNC 426 : else if (cheapest_fractional != cheapest_total)
130 rguo@postgresql.org 2023 :UNC 0 : fraction_neq_total = true;
2024 : : }
2025 : :
2026 : : /*
2027 : : * Notice whether we actually have different paths for the
2028 : : * "cheapest" and "total" cases. This helps avoid generating two
2029 : : * identical ordered append paths.
2030 : : */
5631 tgl@sss.pgh.pa.us 2031 [ + + ]:CBC 15854 : if (cheapest_startup != cheapest_total)
2032 : 48 : startup_neq_total = true;
2033 : :
2034 : : /*
2035 : : * Collect the appropriate child paths. The required logic varies
2036 : : * for the Append and MergeAppend cases.
2037 : : */
2536 2038 [ + + ]: 15854 : if (match_partition_order)
2039 : : {
2040 : : /*
2041 : : * We're going to make a plain Append path. We don't need
2042 : : * most of what accumulate_append_subpath would do, but we do
2043 : : * want to cut out child Appends or MergeAppends if they have
2044 : : * just a single subpath (and hence aren't doing anything
2045 : : * useful).
2046 : : */
2047 : : cheapest_startup =
33 rhaas@postgresql.org 2048 :GNC 3345 : get_singleton_append_subpath(cheapest_startup,
2049 : : &startup.child_append_relid_sets);
2050 : : cheapest_total =
2051 : 3345 : get_singleton_append_subpath(cheapest_total,
2052 : : &total.child_append_relid_sets);
2053 : :
2054 : 3345 : startup.subpaths = lappend(startup.subpaths, cheapest_startup);
2055 : 3345 : total.subpaths = lappend(total.subpaths, cheapest_total);
2056 : :
1523 tomas.vondra@postgre 2057 [ + + ]:CBC 3345 : if (cheapest_fractional)
2058 : : {
2059 : : cheapest_fractional =
33 rhaas@postgresql.org 2060 :GNC 72 : get_singleton_append_subpath(cheapest_fractional,
2061 : : &fractional.child_append_relid_sets);
2062 : 72 : fractional.subpaths =
2063 : 72 : lappend(fractional.subpaths, cheapest_fractional);
2064 : : }
2065 : : }
2066 : : else
2067 : : {
2068 : : /*
2069 : : * Otherwise, rely on accumulate_append_subpath to collect the
2070 : : * child paths for the MergeAppend.
2071 : : */
2536 tgl@sss.pgh.pa.us 2072 :CBC 12509 : accumulate_append_subpath(cheapest_startup,
2073 : : &startup.subpaths, NULL,
2074 : : &startup.child_append_relid_sets);
2075 : 12509 : accumulate_append_subpath(cheapest_total,
2076 : : &total.subpaths, NULL,
2077 : : &total.child_append_relid_sets);
2078 : :
1523 tomas.vondra@postgre 2079 [ + + ]: 12509 : if (cheapest_fractional)
2080 : 376 : accumulate_append_subpath(cheapest_fractional,
2081 : : &fractional.subpaths, NULL,
2082 : : &fractional.child_append_relid_sets);
2083 : : }
2084 : : }
2085 : :
2086 : : /* ... and build the Append or MergeAppend paths */
1119 drowley@postgresql.o 2087 [ + + ]: 6118 : if (match_partition_order)
2088 : : {
2089 : : /* We only need Append */
2536 tgl@sss.pgh.pa.us 2090 : 1256 : add_path(rel, (Path *) create_append_path(root,
2091 : : rel,
2092 : : startup,
2093 : : pathkeys,
2094 : : NULL,
2095 : : 0,
2096 : : false,
2097 : : -1));
2098 [ - + ]: 1256 : if (startup_neq_total)
2536 tgl@sss.pgh.pa.us 2099 :UBC 0 : add_path(rel, (Path *) create_append_path(root,
2100 : : rel,
2101 : : total,
2102 : : pathkeys,
2103 : : NULL,
2104 : : 0,
2105 : : false,
2106 : : -1));
2107 : :
33 rhaas@postgresql.org 2108 [ + + - + ]:GNC 1256 : if (fractional.subpaths && fraction_neq_total)
1523 tomas.vondra@postgre 2109 :LBC (36) : add_path(rel, (Path *) create_append_path(root,
2110 : : rel,
2111 : : fractional,
2112 : : pathkeys,
2113 : : NULL,
2114 : : 0,
2115 : : false,
2116 : : -1));
2117 : : }
2118 : : else
2119 : : {
2120 : : /* We need MergeAppend */
5631 tgl@sss.pgh.pa.us 2121 :CBC 4862 : add_path(rel, (Path *) create_merge_append_path(root,
2122 : : rel,
2123 : : startup.subpaths,
2124 : : startup.child_append_relid_sets,
2125 : : pathkeys,
2126 : : NULL));
2536 2127 [ + + ]: 4862 : if (startup_neq_total)
2128 : 30 : add_path(rel, (Path *) create_merge_append_path(root,
2129 : : rel,
2130 : : total.subpaths,
2131 : : total.child_append_relid_sets,
2132 : : pathkeys,
2133 : : NULL));
2134 : :
33 rhaas@postgresql.org 2135 [ + + - + ]:GNC 4862 : if (fractional.subpaths && fraction_neq_total)
1523 tomas.vondra@postgre 2136 :LBC (134) : add_path(rel, (Path *) create_merge_append_path(root,
2137 : : rel,
2138 : : fractional.subpaths,
2139 : : fractional.child_append_relid_sets,
2140 : : pathkeys,
2141 : : NULL));
2142 : : }
2143 : : }
10841 scrappy@hub.org 2144 :CBC 23792 : }
2145 : :
2146 : : /*
2147 : : * get_cheapest_parameterized_child_path
2148 : : * Get cheapest path for this relation that has exactly the requested
2149 : : * parameterization.
2150 : : *
2151 : : * Returns NULL if unable to create such a path.
2152 : : */
2153 : : static Path *
4634 tgl@sss.pgh.pa.us 2154 : 3483 : get_cheapest_parameterized_child_path(PlannerInfo *root, RelOptInfo *rel,
2155 : : Relids required_outer)
2156 : : {
2157 : : Path *cheapest;
2158 : : ListCell *lc;
2159 : :
2160 : : /*
2161 : : * Look up the cheapest existing path with no more than the needed
2162 : : * parameterization. If it has exactly the needed parameterization, we're
2163 : : * done.
2164 : : */
2165 : 3483 : cheapest = get_cheapest_path_for_pathkeys(rel->pathlist,
2166 : : NIL,
2167 : : required_outer,
2168 : : TOTAL_COST,
2169 : : false);
2170 [ - + ]: 3483 : Assert(cheapest != NULL);
2171 [ + + + + ]: 3483 : if (bms_equal(PATH_REQ_OUTER(cheapest), required_outer))
2172 : 3313 : return cheapest;
2173 : :
2174 : : /*
2175 : : * Otherwise, we can "reparameterize" an existing path to match the given
2176 : : * parameterization, which effectively means pushing down additional
2177 : : * joinquals to be checked within the path's scan. However, some existing
2178 : : * paths might check the available joinquals already while others don't;
2179 : : * therefore, it's not clear which existing path will be cheapest after
2180 : : * reparameterization. We have to go through them all and find out.
2181 : : */
2182 : 170 : cheapest = NULL;
2183 [ + - + + : 590 : foreach(lc, rel->pathlist)
+ + ]
2184 : : {
2185 : 420 : Path *path = (Path *) lfirst(lc);
2186 : :
2187 : : /* Can't use it if it needs more than requested parameterization */
2188 [ + + + + ]: 420 : if (!bms_is_subset(PATH_REQ_OUTER(path), required_outer))
2189 : 12 : continue;
2190 : :
2191 : : /*
2192 : : * Reparameterization can only increase the path's cost, so if it's
2193 : : * already more expensive than the current cheapest, forget it.
2194 : : */
2195 [ + + + + ]: 636 : if (cheapest != NULL &&
2196 : 228 : compare_path_costs(cheapest, path, TOTAL_COST) <= 0)
2197 : 192 : continue;
2198 : :
2199 : : /* Reparameterize if needed, then recheck cost */
2200 [ + + + + ]: 216 : if (!bms_equal(PATH_REQ_OUTER(path), required_outer))
2201 : : {
2202 : 178 : path = reparameterize_path(root, path, required_outer, 1.0);
2203 [ + + ]: 178 : if (path == NULL)
2204 : 16 : continue; /* failed to reparameterize this one */
2205 [ + - - + ]: 162 : Assert(bms_equal(PATH_REQ_OUTER(path), required_outer));
2206 : :
2207 [ - + - - ]: 162 : if (cheapest != NULL &&
4634 tgl@sss.pgh.pa.us 2208 :UBC 0 : compare_path_costs(cheapest, path, TOTAL_COST) <= 0)
2209 : 0 : continue;
2210 : : }
2211 : :
2212 : : /* We have a new best path */
4634 tgl@sss.pgh.pa.us 2213 :CBC 200 : cheapest = path;
2214 : : }
2215 : :
2216 : : /* Return the best path, or NULL if we found no suitable candidate */
2217 : 170 : return cheapest;
2218 : : }
2219 : :
2220 : : /*
2221 : : * accumulate_append_subpath
2222 : : * Add a subpath to the list being built for an Append or MergeAppend.
2223 : : *
2224 : : * It's possible that the child is itself an Append or MergeAppend path, in
2225 : : * which case we can "cut out the middleman" and just add its child paths to
2226 : : * our own list. (We don't try to do this earlier because we need to apply
2227 : : * both levels of transformation to the quals.)
2228 : : *
2229 : : * Note that if we omit a child MergeAppend in this way, we are effectively
2230 : : * omitting a sort step, which seems fine: if the parent is to be an Append,
2231 : : * its result would be unsorted anyway, while if the parent is to be a
2232 : : * MergeAppend, there's no point in a separate sort on a child.
2233 : : *
2234 : : * Normally, either path is a partial path and subpaths is a list of partial
2235 : : * paths, or else path is a non-partial plan and subpaths is a list of those.
2236 : : * However, if path is a parallel-aware Append, then we add its partial path
2237 : : * children to subpaths and the rest to special_subpaths. If the latter is
2238 : : * NULL, we don't flatten the path at all (unless it contains only partial
2239 : : * paths).
2240 : : */
2241 : : static void
33 rhaas@postgresql.org 2242 :GNC 156005 : accumulate_append_subpath(Path *path, List **subpaths, List **special_subpaths,
2243 : : List **child_append_relid_sets)
2244 : : {
5631 tgl@sss.pgh.pa.us 2245 [ + + ]:CBC 156005 : if (IsA(path, AppendPath))
2246 : : {
5453 bruce@momjian.us 2247 : 7876 : AppendPath *apath = (AppendPath *) path;
2248 : :
3022 rhaas@postgresql.org 2249 [ + + + + ]: 7876 : if (!apath->path.parallel_aware || apath->first_partial_path == 0)
2250 : : {
2407 tgl@sss.pgh.pa.us 2251 : 7708 : *subpaths = list_concat(*subpaths, apath->subpaths);
33 rhaas@postgresql.org 2252 :GNC 7708 : *child_append_relid_sets =
2253 : 7708 : lappend(*child_append_relid_sets, path->parent->relids);
2254 : 7708 : *child_append_relid_sets =
2255 : 7708 : list_concat(*child_append_relid_sets,
2256 : 7708 : apath->child_append_relid_sets);
3022 rhaas@postgresql.org 2257 :CBC 7708 : return;
2258 : : }
2259 [ + + ]: 168 : else if (special_subpaths != NULL)
2260 : : {
2261 : : List *new_special_subpaths;
2262 : :
2263 : : /* Split Parallel Append into partial and non-partial subpaths */
2264 : 84 : *subpaths = list_concat(*subpaths,
2265 : 84 : list_copy_tail(apath->subpaths,
2266 : : apath->first_partial_path));
1341 drowley@postgresql.o 2267 : 84 : new_special_subpaths = list_copy_head(apath->subpaths,
2268 : : apath->first_partial_path);
3022 rhaas@postgresql.org 2269 : 84 : *special_subpaths = list_concat(*special_subpaths,
2270 : : new_special_subpaths);
33 rhaas@postgresql.org 2271 :GNC 84 : *child_append_relid_sets =
2272 : 84 : lappend(*child_append_relid_sets, path->parent->relids);
2273 : 84 : *child_append_relid_sets =
2274 : 84 : list_concat(*child_append_relid_sets,
2275 : 84 : apath->child_append_relid_sets);
2986 rhaas@postgresql.org 2276 :CBC 84 : return;
2277 : : }
2278 : : }
4370 tgl@sss.pgh.pa.us 2279 [ + + ]: 148129 : else if (IsA(path, MergeAppendPath))
2280 : : {
2281 : 538 : MergeAppendPath *mpath = (MergeAppendPath *) path;
2282 : :
2407 2283 : 538 : *subpaths = list_concat(*subpaths, mpath->subpaths);
33 rhaas@postgresql.org 2284 :GNC 538 : *child_append_relid_sets =
2285 : 538 : lappend(*child_append_relid_sets, path->parent->relids);
2286 : 538 : *child_append_relid_sets =
2287 : 538 : list_concat(*child_append_relid_sets,
2288 : 538 : mpath->child_append_relid_sets);
3022 rhaas@postgresql.org 2289 :CBC 538 : return;
2290 : : }
2291 : :
2292 : 147675 : *subpaths = lappend(*subpaths, path);
2293 : : }
2294 : :
2295 : : /*
2296 : : * get_singleton_append_subpath
2297 : : * Returns the single subpath of an Append/MergeAppend, or just
2298 : : * return 'path' if it's not a single sub-path Append/MergeAppend.
2299 : : *
2300 : : * As a side effect, whenever we return a single subpath rather than the
2301 : : * original path, add the relid sets for the original path to
2302 : : * child_append_relid_sets, so that those relids don't entirely disappear
2303 : : * from the final plan.
2304 : : *
2305 : : * Note: 'path' must not be a parallel-aware path.
2306 : : */
2307 : : static Path *
33 rhaas@postgresql.org 2308 :GNC 6762 : get_singleton_append_subpath(Path *path, List **child_append_relid_sets)
2309 : : {
2536 tgl@sss.pgh.pa.us 2310 [ - + ]:CBC 6762 : Assert(!path->parallel_aware);
2311 : :
2312 [ + + ]: 6762 : if (IsA(path, AppendPath))
2313 : : {
2314 : 206 : AppendPath *apath = (AppendPath *) path;
2315 : :
2316 [ + + ]: 206 : if (list_length(apath->subpaths) == 1)
2317 : : {
33 rhaas@postgresql.org 2318 :GNC 108 : *child_append_relid_sets =
2319 : 108 : lappend(*child_append_relid_sets, path->parent->relids);
2320 : 108 : *child_append_relid_sets =
2321 : 108 : list_concat(*child_append_relid_sets,
2322 : 108 : apath->child_append_relid_sets);
2536 tgl@sss.pgh.pa.us 2323 :CBC 108 : return (Path *) linitial(apath->subpaths);
2324 : : }
2325 : : }
2326 [ + + ]: 6556 : else if (IsA(path, MergeAppendPath))
2327 : : {
2328 : 174 : MergeAppendPath *mpath = (MergeAppendPath *) path;
2329 : :
2330 [ - + ]: 174 : if (list_length(mpath->subpaths) == 1)
2331 : : {
33 rhaas@postgresql.org 2332 :UNC 0 : *child_append_relid_sets =
2333 : 0 : lappend(*child_append_relid_sets, path->parent->relids);
2334 : 0 : *child_append_relid_sets =
2335 : 0 : list_concat(*child_append_relid_sets,
2336 : 0 : mpath->child_append_relid_sets);
2536 tgl@sss.pgh.pa.us 2337 :UBC 0 : return (Path *) linitial(mpath->subpaths);
2338 : : }
2339 : : }
2340 : :
2536 tgl@sss.pgh.pa.us 2341 :CBC 6654 : return path;
2342 : : }
2343 : :
2344 : : /*
2345 : : * set_dummy_rel_pathlist
2346 : : * Build a dummy path for a relation that's been excluded by constraints
2347 : : *
2348 : : * Rather than inventing a special "dummy" path type, we represent this as an
2349 : : * AppendPath with no members (see also IS_DUMMY_APPEND/IS_DUMMY_REL macros).
2350 : : *
2351 : : * (See also mark_dummy_rel, which does basically the same thing, but is
2352 : : * typically used to change a rel into dummy state after we already made
2353 : : * paths for it.)
2354 : : */
2355 : : static void
6868 2356 : 704 : set_dummy_rel_pathlist(RelOptInfo *rel)
2357 : : {
33 rhaas@postgresql.org 2358 :GNC 704 : AppendPathInput in = {0};
2359 : :
2360 : : /* Set dummy size estimates --- we leave attr_widths[] as zeroes */
6868 tgl@sss.pgh.pa.us 2361 :CBC 704 : rel->rows = 0;
3653 2362 : 704 : rel->reltarget->width = 0;
2363 : :
2364 : : /* Discard any pre-existing paths; no further need for them */
5161 2365 : 704 : rel->pathlist = NIL;
3707 rhaas@postgresql.org 2366 : 704 : rel->partial_pathlist = NIL;
2367 : :
2368 : : /* Set up the dummy path */
33 rhaas@postgresql.org 2369 :GNC 704 : add_path(rel, (Path *) create_append_path(NULL, rel, in,
2370 : : NIL, rel->lateral_relids,
2371 : : 0, false, -1));
2372 : :
2373 : : /*
2374 : : * We set the cheapest-path fields immediately, just in case they were
2375 : : * pointing at some discarded path. This is redundant in current usage
2376 : : * because set_rel_pathlist will do it later, but it's cheap so we keep it
2377 : : * for safety and consistency with mark_dummy_rel.
2378 : : */
6868 tgl@sss.pgh.pa.us 2379 :CBC 704 : set_cheapest(rel);
2380 : 704 : }
2381 : :
2382 : : /*
2383 : : * find_window_run_conditions
2384 : : * Determine if 'wfunc' is really a WindowFunc and call its prosupport
2385 : : * function to determine the function's monotonic properties. We then
2386 : : * see if 'opexpr' can be used to short-circuit execution.
2387 : : *
2388 : : * For example row_number() over (order by ...) always produces a value one
2389 : : * higher than the previous. If someone has a window function in a subquery
2390 : : * and has a WHERE clause in the outer query to filter rows <= 10, then we may
2391 : : * as well stop processing the windowagg once the row number reaches 11. Here
2392 : : * we check if 'opexpr' might help us to stop doing needless extra processing
2393 : : * in WindowAgg nodes.
2394 : : *
2395 : : * '*keep_original' is set to true if the caller should also use 'opexpr' for
2396 : : * its original purpose. This is set to false if the caller can assume that
2397 : : * the run condition will handle all of the required filtering.
2398 : : *
2399 : : * Returns true if 'opexpr' was found to be useful and was added to the
2400 : : * WindowFunc's runCondition. We also set *keep_original accordingly and add
2401 : : * 'attno' to *run_cond_attrs offset by FirstLowInvalidHeapAttributeNumber.
2402 : : * If the 'opexpr' cannot be used then we set *keep_original to true and
2403 : : * return false.
2404 : : */
2405 : : static bool
166 drowley@postgresql.o 2406 :GNC 120 : find_window_run_conditions(Query *subquery, AttrNumber attno,
2407 : : WindowFunc *wfunc, OpExpr *opexpr, bool wfunc_left,
2408 : : bool *keep_original, Bitmapset **run_cond_attrs)
2409 : : {
2410 : : Oid prosupport;
2411 : : Expr *otherexpr;
2412 : : SupportRequestWFuncMonotonic req;
2413 : : SupportRequestWFuncMonotonic *res;
2414 : : WindowClause *wclause;
2415 : : List *opinfos;
2416 : : OpExpr *runopexpr;
2417 : : Oid runoperator;
2418 : : ListCell *lc;
2419 : :
1437 drowley@postgresql.o 2420 :CBC 120 : *keep_original = true;
2421 : :
2422 [ - + ]: 120 : while (IsA(wfunc, RelabelType))
1437 drowley@postgresql.o 2423 :UBC 0 : wfunc = (WindowFunc *) ((RelabelType *) wfunc)->arg;
2424 : :
2425 : : /* we can only work with window functions */
1437 drowley@postgresql.o 2426 [ + + ]:CBC 120 : if (!IsA(wfunc, WindowFunc))
2427 : 12 : return false;
2428 : :
2429 : : /* can't use it if there are subplans in the WindowFunc */
1094 2430 [ + + ]: 108 : if (contain_subplans((Node *) wfunc))
2431 : 3 : return false;
2432 : :
1437 2433 : 105 : prosupport = get_func_support(wfunc->winfnoid);
2434 : :
2435 : : /* Check if there's a support function for 'wfunc' */
2436 [ + + ]: 105 : if (!OidIsValid(prosupport))
2437 : 9 : return false;
2438 : :
2439 : : /* get the Expr from the other side of the OpExpr */
2440 [ + + ]: 96 : if (wfunc_left)
2441 : 84 : otherexpr = lsecond(opexpr->args);
2442 : : else
2443 : 12 : otherexpr = linitial(opexpr->args);
2444 : :
2445 : : /*
2446 : : * The value being compared must not change during the evaluation of the
2447 : : * window partition.
2448 : : */
2449 [ - + ]: 96 : if (!is_pseudo_constant_clause((Node *) otherexpr))
1437 drowley@postgresql.o 2450 :UBC 0 : return false;
2451 : :
2452 : : /* find the window clause belonging to the window function */
1437 drowley@postgresql.o 2453 :CBC 96 : wclause = (WindowClause *) list_nth(subquery->windowClause,
2454 : 96 : wfunc->winref - 1);
2455 : :
2456 : 96 : req.type = T_SupportRequestWFuncMonotonic;
2457 : 96 : req.window_func = wfunc;
2458 : 96 : req.window_clause = wclause;
2459 : :
2460 : : /* call the support function */
2461 : : res = (SupportRequestWFuncMonotonic *)
2462 : 96 : DatumGetPointer(OidFunctionCall1(prosupport,
2463 : : PointerGetDatum(&req)));
2464 : :
2465 : : /*
2466 : : * Nothing to do if the function is neither monotonically increasing nor
2467 : : * monotonically decreasing.
2468 : : */
2469 [ + - - + ]: 96 : if (res == NULL || res->monotonic == MONOTONICFUNC_NONE)
1437 drowley@postgresql.o 2470 :UBC 0 : return false;
2471 : :
1437 drowley@postgresql.o 2472 :CBC 96 : runopexpr = NULL;
2473 : 96 : runoperator = InvalidOid;
343 peter@eisentraut.org 2474 : 96 : opinfos = get_op_index_interpretation(opexpr->opno);
2475 : :
1437 drowley@postgresql.o 2476 [ + - + - : 96 : foreach(lc, opinfos)
+ - ]
2477 : : {
343 peter@eisentraut.org 2478 : 96 : OpIndexInterpretation *opinfo = (OpIndexInterpretation *) lfirst(lc);
2479 : 96 : CompareType cmptype = opinfo->cmptype;
2480 : :
2481 : : /* handle < / <= */
2482 [ + + + + ]: 96 : if (cmptype == COMPARE_LT || cmptype == COMPARE_LE)
2483 : : {
2484 : : /*
2485 : : * < / <= is supported for monotonically increasing functions in
2486 : : * the form <wfunc> op <pseudoconst> and <pseudoconst> op <wfunc>
2487 : : * for monotonically decreasing functions.
2488 : : */
1437 drowley@postgresql.o 2489 [ + + + + ]: 69 : if ((wfunc_left && (res->monotonic & MONOTONICFUNC_INCREASING)) ||
2490 [ + + + + ]: 9 : (!wfunc_left && (res->monotonic & MONOTONICFUNC_DECREASING)))
2491 : : {
2492 : 63 : *keep_original = false;
2493 : 63 : runopexpr = opexpr;
2494 : 63 : runoperator = opexpr->opno;
2495 : : }
2496 : 69 : break;
2497 : : }
2498 : : /* handle > / >= */
343 peter@eisentraut.org 2499 [ + + + + ]: 27 : else if (cmptype == COMPARE_GT || cmptype == COMPARE_GE)
2500 : : {
2501 : : /*
2502 : : * > / >= is supported for monotonically decreasing functions in
2503 : : * the form <wfunc> op <pseudoconst> and <pseudoconst> op <wfunc>
2504 : : * for monotonically increasing functions.
2505 : : */
1437 drowley@postgresql.o 2506 [ + + - + ]: 9 : if ((wfunc_left && (res->monotonic & MONOTONICFUNC_DECREASING)) ||
2507 [ + - + - ]: 6 : (!wfunc_left && (res->monotonic & MONOTONICFUNC_INCREASING)))
2508 : : {
2509 : 9 : *keep_original = false;
2510 : 9 : runopexpr = opexpr;
2511 : 9 : runoperator = opexpr->opno;
2512 : : }
2513 : 9 : break;
2514 : : }
2515 : : /* handle = */
343 peter@eisentraut.org 2516 [ + - ]: 18 : else if (cmptype == COMPARE_EQ)
2517 : : {
2518 : : CompareType newcmptype;
2519 : :
2520 : : /*
2521 : : * When both monotonically increasing and decreasing then the
2522 : : * return value of the window function will be the same each time.
2523 : : * We can simply use 'opexpr' as the run condition without
2524 : : * modifying it.
2525 : : */
1437 drowley@postgresql.o 2526 [ + + ]: 18 : if ((res->monotonic & MONOTONICFUNC_BOTH) == MONOTONICFUNC_BOTH)
2527 : : {
2528 : 3 : *keep_original = false;
2529 : 3 : runopexpr = opexpr;
1318 2530 : 3 : runoperator = opexpr->opno;
1437 2531 : 3 : break;
2532 : : }
2533 : :
2534 : : /*
2535 : : * When monotonically increasing we make a qual with <wfunc> <=
2536 : : * <value> or <value> >= <wfunc> in order to filter out values
2537 : : * which are above the value in the equality condition. For
2538 : : * monotonically decreasing functions we want to filter values
2539 : : * below the value in the equality condition.
2540 : : */
2541 [ + - ]: 15 : if (res->monotonic & MONOTONICFUNC_INCREASING)
343 peter@eisentraut.org 2542 [ + - ]: 15 : newcmptype = wfunc_left ? COMPARE_LE : COMPARE_GE;
2543 : : else
343 peter@eisentraut.org 2544 [ # # ]:UBC 0 : newcmptype = wfunc_left ? COMPARE_GE : COMPARE_LE;
2545 : :
2546 : : /* We must keep the original equality qual */
1437 drowley@postgresql.o 2547 :CBC 15 : *keep_original = true;
2548 : 15 : runopexpr = opexpr;
2549 : :
2550 : : /* determine the operator to use for the WindowFuncRunCondition */
343 peter@eisentraut.org 2551 : 15 : runoperator = get_opfamily_member_for_cmptype(opinfo->opfamily_id,
2552 : : opinfo->oplefttype,
2553 : : opinfo->oprighttype,
2554 : : newcmptype);
1437 drowley@postgresql.o 2555 : 15 : break;
2556 : : }
2557 : : }
2558 : :
2559 [ + + ]: 96 : if (runopexpr != NULL)
2560 : : {
2561 : : WindowFuncRunCondition *wfuncrc;
2562 : :
679 2563 : 90 : wfuncrc = makeNode(WindowFuncRunCondition);
2564 : 90 : wfuncrc->opno = runoperator;
2565 : 90 : wfuncrc->inputcollid = runopexpr->inputcollid;
2566 : 90 : wfuncrc->wfunc_left = wfunc_left;
2567 : 90 : wfuncrc->arg = copyObject(otherexpr);
2568 : :
2569 : 90 : wfunc->runCondition = lappend(wfunc->runCondition, wfuncrc);
2570 : :
2571 : : /* record that this attno was used in a run condition */
1388 2572 : 90 : *run_cond_attrs = bms_add_member(*run_cond_attrs,
2573 : : attno - FirstLowInvalidHeapAttributeNumber);
1437 2574 : 90 : return true;
2575 : : }
2576 : :
2577 : : /* unsupported OpExpr */
2578 : 6 : return false;
2579 : : }
2580 : :
2581 : : /*
2582 : : * check_and_push_window_quals
2583 : : * Check if 'clause' is a qual that can be pushed into a WindowFunc
2584 : : * as a 'runCondition' qual. These, when present, allow some unnecessary
2585 : : * work to be skipped during execution.
2586 : : *
2587 : : * 'run_cond_attrs' will be populated with all targetlist resnos of subquery
2588 : : * targets (offset by FirstLowInvalidHeapAttributeNumber) that we pushed
2589 : : * window quals for.
2590 : : *
2591 : : * Returns true if the caller still must keep the original qual or false if
2592 : : * the caller can safely ignore the original qual because the WindowAgg node
2593 : : * will use the runCondition to stop returning tuples.
2594 : : */
2595 : : static bool
166 drowley@postgresql.o 2596 :GNC 126 : check_and_push_window_quals(Query *subquery, Node *clause,
2597 : : Bitmapset **run_cond_attrs)
2598 : : {
1437 drowley@postgresql.o 2599 :CBC 126 : OpExpr *opexpr = (OpExpr *) clause;
2600 : 126 : bool keep_original = true;
2601 : : Var *var1;
2602 : : Var *var2;
2603 : :
2604 : : /* We're only able to use OpExprs with 2 operands */
2605 [ + + ]: 126 : if (!IsA(opexpr, OpExpr))
2606 : 9 : return true;
2607 : :
2608 [ - + ]: 117 : if (list_length(opexpr->args) != 2)
1437 drowley@postgresql.o 2609 :UBC 0 : return true;
2610 : :
2611 : : /*
2612 : : * Currently, we restrict this optimization to strict OpExprs. The reason
2613 : : * for this is that during execution, once the runcondition becomes false,
2614 : : * we stop evaluating WindowFuncs. To avoid leaving around stale window
2615 : : * function result values, we set them to NULL. Having only strict
2616 : : * OpExprs here ensures that we properly filter out the tuples with NULLs
2617 : : * in the top-level WindowAgg.
2618 : : */
1194 drowley@postgresql.o 2619 :CBC 117 : set_opfuncid(opexpr);
2620 [ - + ]: 117 : if (!func_strict(opexpr->opfuncid))
1194 drowley@postgresql.o 2621 :UBC 0 : return true;
2622 : :
2623 : : /*
2624 : : * Check for plain Vars that reference window functions in the subquery.
2625 : : * If we find any, we'll ask find_window_run_conditions() if 'opexpr' can
2626 : : * be used as part of the run condition.
2627 : : */
2628 : :
2629 : : /* Check the left side of the OpExpr */
1437 drowley@postgresql.o 2630 :CBC 117 : var1 = linitial(opexpr->args);
2631 [ + + + - ]: 117 : if (IsA(var1, Var) && var1->varattno > 0)
2632 : : {
2633 : 99 : TargetEntry *tle = list_nth(subquery->targetList, var1->varattno - 1);
2634 : 99 : WindowFunc *wfunc = (WindowFunc *) tle->expr;
2635 : :
166 drowley@postgresql.o 2636 [ + + ]:GNC 99 : if (find_window_run_conditions(subquery, tle->resno, wfunc, opexpr,
2637 : : true, &keep_original, run_cond_attrs))
1437 drowley@postgresql.o 2638 :CBC 81 : return keep_original;
2639 : : }
2640 : :
2641 : : /* and check the right side */
2642 : 36 : var2 = lsecond(opexpr->args);
2643 [ + + + - ]: 36 : if (IsA(var2, Var) && var2->varattno > 0)
2644 : : {
2645 : 21 : TargetEntry *tle = list_nth(subquery->targetList, var2->varattno - 1);
2646 : 21 : WindowFunc *wfunc = (WindowFunc *) tle->expr;
2647 : :
166 drowley@postgresql.o 2648 [ + + ]:GNC 21 : if (find_window_run_conditions(subquery, tle->resno, wfunc, opexpr,
2649 : : false, &keep_original, run_cond_attrs))
1437 drowley@postgresql.o 2650 :CBC 9 : return keep_original;
2651 : : }
2652 : :
2653 : 27 : return true;
2654 : : }
2655 : :
2656 : : /*
2657 : : * set_subquery_pathlist
2658 : : * Generate SubqueryScan access paths for a subquery RTE
2659 : : *
2660 : : * We don't currently support generating parameterized paths for subqueries
2661 : : * by pushing join clauses down into them; it seems too expensive to re-plan
2662 : : * the subquery multiple times to consider different alternatives.
2663 : : * (XXX that could stand to be reconsidered, now that we use Paths.)
2664 : : * So the paths made here will be parameterized if the subquery contains
2665 : : * LATERAL references, otherwise not. As long as that's true, there's no need
2666 : : * for a separate set_subquery_size phase: just make the paths right away.
2667 : : */
2668 : : static void
7588 tgl@sss.pgh.pa.us 2669 : 13450 : set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
2670 : : Index rti, RangeTblEntry *rte)
2671 : : {
7583 2672 : 13450 : Query *parse = root->parse;
9008 2673 : 13450 : Query *subquery = rte->subquery;
2674 : : bool trivial_pathtarget;
2675 : : Relids required_outer;
2676 : : pushdown_safety_info safetyInfo;
2677 : : double tuple_fraction;
2678 : : RelOptInfo *sub_final_rel;
1388 drowley@postgresql.o 2679 : 13450 : Bitmapset *run_cond_attrs = NULL;
2680 : : ListCell *lc;
2681 : : char *plan_name;
2682 : :
2683 : : /*
2684 : : * Must copy the Query so that planning doesn't mess up the RTE contents
2685 : : * (really really need to fix the planner to not scribble on its input,
2686 : : * someday ... but see remove_unused_subquery_outputs to start with).
2687 : : */
6214 tgl@sss.pgh.pa.us 2688 : 13450 : subquery = copyObject(subquery);
2689 : :
2690 : : /*
2691 : : * If it's a LATERAL subquery, it might contain some Vars of the current
2692 : : * query level, requiring it to be treated as parameterized, even though
2693 : : * we don't support pushing down join quals into subqueries.
2694 : : */
4949 2695 : 13450 : required_outer = rel->lateral_relids;
2696 : :
2697 : : /*
2698 : : * Zero out result area for subquery_is_pushdown_safe, so that it can set
2699 : : * flags as needed while recursing. In particular, we need a workspace
2700 : : * for keeping track of the reasons why columns are unsafe to reference.
2701 : : * These reasons are stored in the bits inside unsafeFlags[i] when we
2702 : : * discover reasons that column i of the subquery is unsafe to be used in
2703 : : * a pushed-down qual.
2704 : : */
4279 2705 : 13450 : memset(&safetyInfo, 0, sizeof(safetyInfo));
1094 drowley@postgresql.o 2706 : 13450 : safetyInfo.unsafeFlags = (unsigned char *)
2707 : 13450 : palloc0((list_length(subquery->targetList) + 1) * sizeof(unsigned char));
2708 : :
2709 : : /*
2710 : : * If the subquery has the "security_barrier" flag, it means the subquery
2711 : : * originated from a view that must enforce row-level security. Then we
2712 : : * must not push down quals that contain leaky functions. (Ideally this
2713 : : * would be checked inside subquery_is_pushdown_safe, but since we don't
2714 : : * currently pass the RTE to that function, we must do it here.)
2715 : : */
4279 tgl@sss.pgh.pa.us 2716 : 13450 : safetyInfo.unsafeLeaky = rte->security_barrier;
2717 : :
2718 : : /*
2719 : : * If there are any restriction clauses that have been attached to the
2720 : : * subquery relation, consider pushing them down to become WHERE or HAVING
2721 : : * quals of the subquery itself. This transformation is useful because it
2722 : : * may allow us to generate a better plan for the subquery than evaluating
2723 : : * all the subquery output rows and then filtering them.
2724 : : *
2725 : : * There are several cases where we cannot push down clauses. Restrictions
2726 : : * involving the subquery are checked by subquery_is_pushdown_safe().
2727 : : * Restrictions on individual clauses are checked by
2728 : : * qual_is_pushdown_safe(). Also, we don't want to push down
2729 : : * pseudoconstant clauses; better to have the gating node above the
2730 : : * subquery.
2731 : : *
2732 : : * Non-pushed-down clauses will get evaluated as qpquals of the
2733 : : * SubqueryScan node.
2734 : : *
2735 : : * XXX Are there any cases where we want to make a policy decision not to
2736 : : * push down a pushable qual, because it'd result in a worse plan?
2737 : : */
8599 2738 [ + + + + ]: 15030 : if (rel->baserestrictinfo != NIL &&
4279 2739 : 1580 : subquery_is_pushdown_safe(subquery, subquery, &safetyInfo))
2740 : : {
2741 : : /* OK to consider pushing down individual quals */
9008 2742 : 1507 : List *upperrestrictlist = NIL;
2743 : : ListCell *l;
2744 : :
7963 neilc@samurai.com 2745 [ + - + + : 4036 : foreach(l, rel->baserestrictinfo)
+ + ]
2746 : : {
2747 : 2529 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
1437 drowley@postgresql.o 2748 : 2529 : Node *clause = (Node *) rinfo->clause;
2749 : :
1094 2750 [ + + ]: 2529 : if (rinfo->pseudoconstant)
2751 : : {
2752 : 2 : upperrestrictlist = lappend(upperrestrictlist, rinfo);
2753 : 2 : continue;
2754 : : }
2755 : :
2756 [ + + + - ]: 2527 : switch (qual_is_pushdown_safe(subquery, rti, rinfo, &safetyInfo))
2757 : : {
2758 : 1975 : case PUSHDOWN_SAFE:
2759 : : /* Push it down */
2760 : 1975 : subquery_push_qual(subquery, rte, rti, clause);
2761 : 1975 : break;
2762 : :
2763 : 126 : case PUSHDOWN_WINDOWCLAUSE_RUNCOND:
2764 : :
2765 : : /*
2766 : : * Since we can't push the qual down into the subquery,
2767 : : * check if it happens to reference a window function. If
2768 : : * so then it might be useful to use for the WindowAgg's
2769 : : * runCondition.
2770 : : */
2771 [ + - + + ]: 252 : if (!subquery->hasWindowFuncs ||
166 drowley@postgresql.o 2772 :GNC 126 : check_and_push_window_quals(subquery, clause,
2773 : : &run_cond_attrs))
2774 : : {
2775 : : /*
2776 : : * subquery has no window funcs or the clause is not a
2777 : : * suitable window run condition qual or it is, but
2778 : : * the original must also be kept in the upper query.
2779 : : */
1094 drowley@postgresql.o 2780 :CBC 51 : upperrestrictlist = lappend(upperrestrictlist, rinfo);
2781 : : }
2782 : 126 : break;
2783 : :
2784 : 426 : case PUSHDOWN_UNSAFE:
1437 2785 : 426 : upperrestrictlist = lappend(upperrestrictlist, rinfo);
1094 2786 : 426 : break;
2787 : : }
2788 : : }
9008 tgl@sss.pgh.pa.us 2789 : 1507 : rel->baserestrictinfo = upperrestrictlist;
2790 : : /* We don't bother recomputing baserestrict_min_security */
2791 : : }
2792 : :
1094 drowley@postgresql.o 2793 : 13450 : pfree(safetyInfo.unsafeFlags);
2794 : :
2795 : : /*
2796 : : * The upper query might not use all the subquery's output columns; if
2797 : : * not, we can simplify. Pass the attributes that were pushed down into
2798 : : * WindowAgg run conditions to ensure we don't accidentally think those
2799 : : * are unused.
2800 : : */
1388 2801 : 13450 : remove_unused_subquery_outputs(subquery, rel, run_cond_attrs);
2802 : :
2803 : : /*
2804 : : * We can safely pass the outer tuple_fraction down to the subquery if the
2805 : : * outer level has no joining, aggregation, or sorting to do. Otherwise
2806 : : * we'd better tell the subquery to plan for full retrieval. (XXX This
2807 : : * could probably be made more intelligent ...)
2808 : : */
7583 tgl@sss.pgh.pa.us 2809 [ + + ]: 13450 : if (parse->hasAggs ||
2810 [ + + ]: 9899 : parse->groupClause ||
3956 andres@anarazel.de 2811 [ + - ]: 9890 : parse->groupingSets ||
1244 tgl@sss.pgh.pa.us 2812 [ + - ]: 9890 : root->hasHavingQual ||
7583 2813 [ + + ]: 9890 : parse->distinctClause ||
2814 [ + + + + ]: 13338 : parse->sortClause ||
887 2815 : 3712 : bms_membership(root->all_baserels) == BMS_MULTIPLE)
7583 2816 : 10748 : tuple_fraction = 0.0; /* default case */
2817 : : else
2818 : 2702 : tuple_fraction = root->tuple_fraction;
2819 : :
2820 : : /* plan_params should not be in use in current query level */
4939 2821 [ - + ]: 13450 : Assert(root->plan_params == NIL);
2822 : :
2823 : : /* Generate a subroot and Paths for the subquery */
159 rhaas@postgresql.org 2824 :GNC 13450 : plan_name = choose_plan_name(root->glob, rte->eref->aliasname, false);
2825 : 13450 : rel->subroot = subquery_planner(root->glob, subquery, plan_name,
2826 : : root, false, tuple_fraction, NULL);
2827 : :
2828 : : /* Isolate the params needed by this specific subplan */
4939 tgl@sss.pgh.pa.us 2829 :CBC 13450 : rel->subplan_params = root->plan_params;
2830 : 13450 : root->plan_params = NIL;
2831 : :
2832 : : /*
2833 : : * It's possible that constraint exclusion proved the subquery empty. If
2834 : : * so, it's desirable to produce an unadorned dummy path so that we will
2835 : : * recognize appropriate optimizations at this query level.
2836 : : */
3660 2837 : 13450 : sub_final_rel = fetch_upper_rel(rel->subroot, UPPERREL_FINAL, NULL);
2838 : :
2839 [ + + ]: 13450 : if (IS_DUMMY_REL(sub_final_rel))
2840 : : {
5286 2841 : 63 : set_dummy_rel_pathlist(rel);
2842 : 63 : return;
2843 : : }
2844 : :
2845 : : /*
2846 : : * Mark rel with estimated output rows, width, etc. Note that we have to
2847 : : * do this before generating outer-query paths, else cost_subqueryscan is
2848 : : * not happy.
2849 : : */
5307 2850 : 13387 : set_subquery_size_estimates(root, rel);
2851 : :
2852 : : /*
2853 : : * Also detect whether the reltarget is trivial, so that we can pass that
2854 : : * info to cost_subqueryscan (rather than re-deriving it multiple times).
2855 : : * It's trivial if it fetches all the subplan output columns in order.
2856 : : */
1335 2857 [ + + ]: 13387 : if (list_length(rel->reltarget->exprs) != list_length(subquery->targetList))
2858 : 8345 : trivial_pathtarget = false;
2859 : : else
2860 : : {
2861 : 5042 : trivial_pathtarget = true;
2862 [ + + + + : 16412 : foreach(lc, rel->reltarget->exprs)
+ + ]
2863 : : {
2864 : 11519 : Node *node = (Node *) lfirst(lc);
2865 : : Var *var;
2866 : :
2867 [ - + ]: 11519 : if (!IsA(node, Var))
2868 : : {
1335 tgl@sss.pgh.pa.us 2869 :UBC 0 : trivial_pathtarget = false;
2870 : 0 : break;
2871 : : }
1335 tgl@sss.pgh.pa.us 2872 :CBC 11519 : var = (Var *) node;
2873 [ + - ]: 11519 : if (var->varno != rti ||
2874 [ + + ]: 11519 : var->varattno != foreach_current_index(lc) + 1)
2875 : : {
2876 : 149 : trivial_pathtarget = false;
2877 : 149 : break;
2878 : : }
2879 : : }
2880 : : }
2881 : :
2882 : : /*
2883 : : * For each Path that subquery_planner produced, make a SubqueryScanPath
2884 : : * in the outer query.
2885 : : */
3660 2886 [ + - + + : 27864 : foreach(lc, sub_final_rel->pathlist)
+ + ]
2887 : : {
2888 : 14477 : Path *subpath = (Path *) lfirst(lc);
2889 : : List *pathkeys;
2890 : :
2891 : : /* Convert subpath's pathkeys to outer representation */
2892 : 14477 : pathkeys = convert_subquery_pathkeys(root,
2893 : : rel,
2894 : : subpath->pathkeys,
2895 : : make_tlist_from_pathtarget(subpath->pathtarget));
2896 : :
2897 : : /* Generate outer path using this subpath */
2898 : 14477 : add_path(rel, (Path *)
2899 : 14477 : create_subqueryscan_path(root, rel, subpath,
2900 : : trivial_pathtarget,
2901 : : pathkeys, required_outer));
2902 : : }
2903 : :
2904 : : /* If outer rel allows parallelism, do same for partial paths. */
2881 rhaas@postgresql.org 2905 [ + + + + ]: 13387 : if (rel->consider_parallel && bms_is_empty(required_outer))
2906 : : {
2907 : : /* If consider_parallel is false, there should be no partial paths. */
2908 [ + + - + ]: 7911 : Assert(sub_final_rel->consider_parallel ||
2909 : : sub_final_rel->partial_pathlist == NIL);
2910 : :
2911 : : /* Same for partial paths. */
2912 [ + + + + : 7938 : foreach(lc, sub_final_rel->partial_pathlist)
+ + ]
2913 : : {
2914 : 27 : Path *subpath = (Path *) lfirst(lc);
2915 : : List *pathkeys;
2916 : :
2917 : : /* Convert subpath's pathkeys to outer representation */
2918 : 27 : pathkeys = convert_subquery_pathkeys(root,
2919 : : rel,
2920 : : subpath->pathkeys,
2921 : : make_tlist_from_pathtarget(subpath->pathtarget));
2922 : :
2923 : : /* Generate outer path using this subpath */
2924 : 27 : add_partial_path(rel, (Path *)
2925 : 27 : create_subqueryscan_path(root, rel, subpath,
2926 : : trivial_pathtarget,
2927 : : pathkeys,
2928 : : required_outer));
2929 : : }
2930 : : }
2931 : : }
2932 : :
2933 : : /*
2934 : : * set_function_pathlist
2935 : : * Build the (single) access path for a function RTE
2936 : : */
2937 : : static void
7588 tgl@sss.pgh.pa.us 2938 : 27918 : set_function_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
2939 : : {
2940 : : Relids required_outer;
4497 2941 : 27918 : List *pathkeys = NIL;
2942 : :
2943 : : /*
2944 : : * We don't support pushing join clauses into the quals of a function
2945 : : * scan, but it could still have required parameterization due to LATERAL
2946 : : * refs in the function expression.
2947 : : */
4949 2948 : 27918 : required_outer = rel->lateral_relids;
2949 : :
2950 : : /*
2951 : : * The result is considered unordered unless ORDINALITY was used, in which
2952 : : * case it is ordered by the ordinal column (the last one). See if we
2953 : : * care, by checking for uses of that Var in equivalence classes.
2954 : : */
4497 2955 [ + + ]: 27918 : if (rte->funcordinality)
2956 : : {
2957 : 479 : AttrNumber ordattno = rel->max_attr;
2958 : 479 : Var *var = NULL;
2959 : : ListCell *lc;
2960 : :
2961 : : /*
2962 : : * Is there a Var for it in rel's targetlist? If not, the query did
2963 : : * not reference the ordinality column, or at least not in any way
2964 : : * that would be interesting for sorting.
2965 : : */
3653 2966 [ + - + + : 1071 : foreach(lc, rel->reltarget->exprs)
+ + ]
2967 : : {
4497 2968 : 1068 : Var *node = (Var *) lfirst(lc);
2969 : :
2970 : : /* checking varno/varlevelsup is just paranoia */
2971 [ + - ]: 1068 : if (IsA(node, Var) &&
2972 [ + + ]: 1068 : node->varattno == ordattno &&
2973 [ + - ]: 476 : node->varno == rel->relid &&
2974 [ + - ]: 476 : node->varlevelsup == 0)
2975 : : {
2976 : 476 : var = node;
2977 : 476 : break;
2978 : : }
2979 : : }
2980 : :
2981 : : /*
2982 : : * Try to build pathkeys for this Var with int8 sorting. We tell
2983 : : * build_expression_pathkey not to build any new equivalence class; if
2984 : : * the Var isn't already mentioned in some EC, it means that nothing
2985 : : * cares about the ordering.
2986 : : */
2987 [ + + ]: 479 : if (var)
2988 : 476 : pathkeys = build_expression_pathkey(root,
2989 : : (Expr *) var,
2990 : : Int8LessOperator,
2991 : : rel->relids,
2992 : : false);
2993 : : }
2994 : :
2995 : : /* Generate appropriate path */
2996 : 27918 : add_path(rel, create_functionscan_path(root, rel,
2997 : : pathkeys, required_outer));
8708 2998 : 27918 : }
2999 : :
3000 : : /*
3001 : : * set_values_pathlist
3002 : : * Build the (single) access path for a VALUES RTE
3003 : : */
3004 : : static void
7165 mail@joeconway.com 3005 : 4326 : set_values_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
3006 : : {
3007 : : Relids required_outer;
3008 : :
3009 : : /*
3010 : : * We don't support pushing join clauses into the quals of a values scan,
3011 : : * but it could still have required parameterization due to LATERAL refs
3012 : : * in the values expressions.
3013 : : */
4949 tgl@sss.pgh.pa.us 3014 : 4326 : required_outer = rel->lateral_relids;
3015 : :
3016 : : /* Generate appropriate path */
4963 3017 : 4326 : add_path(rel, create_valuesscan_path(root, rel, required_outer));
7165 mail@joeconway.com 3018 : 4326 : }
3019 : :
3020 : : /*
3021 : : * set_tablefunc_pathlist
3022 : : * Build the (single) access path for a table func RTE
3023 : : */
3024 : : static void
3294 alvherre@alvh.no-ip. 3025 : 311 : set_tablefunc_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
3026 : : {
3027 : : Relids required_outer;
3028 : :
3029 : : /*
3030 : : * We don't support pushing join clauses into the quals of a tablefunc
3031 : : * scan, but it could still have required parameterization due to LATERAL
3032 : : * refs in the function expression.
3033 : : */
3034 : 311 : required_outer = rel->lateral_relids;
3035 : :
3036 : : /* Generate appropriate path */
3037 : 311 : add_path(rel, create_tablefuncscan_path(root, rel,
3038 : : required_outer));
3039 : 311 : }
3040 : :
3041 : : /*
3042 : : * set_cte_pathlist
3043 : : * Build the (single) access path for a non-self-reference CTE RTE
3044 : : *
3045 : : * There's no need for a separate set_cte_size phase, since we don't
3046 : : * support join-qual-parameterized paths for CTEs.
3047 : : */
3048 : : static void
6371 tgl@sss.pgh.pa.us 3049 : 2372 : set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
3050 : : {
3051 : : Path *ctepath;
3052 : : Plan *cteplan;
3053 : : PlannerInfo *cteroot;
3054 : : Index levelsup;
3055 : : List *pathkeys;
3056 : : int ndx;
3057 : : ListCell *lc;
3058 : : int plan_id;
3059 : : Relids required_outer;
3060 : :
3061 : : /*
3062 : : * Find the referenced CTE, and locate the path and plan previously made
3063 : : * for it.
3064 : : */
3065 : 2372 : levelsup = rte->ctelevelsup;
3066 : 2372 : cteroot = root;
3067 [ + + ]: 4137 : while (levelsup-- > 0)
3068 : : {
3069 : 1765 : cteroot = cteroot->parent_root;
3070 [ - + ]: 1765 : if (!cteroot) /* shouldn't happen */
6371 tgl@sss.pgh.pa.us 3071 [ # # ]:UBC 0 : elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
3072 : : }
3073 : :
3074 : : /*
3075 : : * Note: cte_plan_ids can be shorter than cteList, if we are still working
3076 : : * on planning the CTEs (ie, this is a side-reference from another CTE).
3077 : : * So we mustn't use forboth here.
3078 : : */
6371 tgl@sss.pgh.pa.us 3079 :CBC 2372 : ndx = 0;
3080 [ + - + - : 3211 : foreach(lc, cteroot->parse->cteList)
+ - ]
3081 : : {
3082 : 3211 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
3083 : :
3084 [ + + ]: 3211 : if (strcmp(cte->ctename, rte->ctename) == 0)
3085 : 2372 : break;
3086 : 839 : ndx++;
3087 : : }
3088 [ - + ]: 2372 : if (lc == NULL) /* shouldn't happen */
6371 tgl@sss.pgh.pa.us 3089 [ # # ]:UBC 0 : elog(ERROR, "could not find CTE \"%s\"", rte->ctename);
6371 tgl@sss.pgh.pa.us 3090 [ - + ]:CBC 2372 : if (ndx >= list_length(cteroot->cte_plan_ids))
6371 tgl@sss.pgh.pa.us 3091 [ # # ]:UBC 0 : elog(ERROR, "could not find plan for CTE \"%s\"", rte->ctename);
6371 tgl@sss.pgh.pa.us 3092 :CBC 2372 : plan_id = list_nth_int(cteroot->cte_plan_ids, ndx);
1424 3093 [ - + ]: 2372 : if (plan_id <= 0)
1424 tgl@sss.pgh.pa.us 3094 [ # # ]:UBC 0 : elog(ERROR, "no plan was made for CTE \"%s\"", rte->ctename);
3095 : :
719 tgl@sss.pgh.pa.us 3096 [ - + ]:CBC 2372 : Assert(list_length(root->glob->subpaths) == list_length(root->glob->subplans));
3097 : 2372 : ctepath = (Path *) list_nth(root->glob->subpaths, plan_id - 1);
6371 3098 : 2372 : cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
3099 : :
3100 : : /* Mark rel with estimated output rows, width, etc */
3660 3101 : 2372 : set_cte_size_estimates(root, rel, cteplan->plan_rows);
3102 : :
3103 : : /* Convert the ctepath's pathkeys to outer query's representation */
719 3104 : 2372 : pathkeys = convert_subquery_pathkeys(root,
3105 : : rel,
3106 : : ctepath->pathkeys,
3107 : : cteplan->targetlist);
3108 : :
3109 : : /*
3110 : : * We don't support pushing join clauses into the quals of a CTE scan, but
3111 : : * it could still have required parameterization due to LATERAL refs in
3112 : : * its tlist.
3113 : : */
4949 3114 : 2372 : required_outer = rel->lateral_relids;
3115 : :
3116 : : /* Generate appropriate path */
719 3117 : 2372 : add_path(rel, create_ctescan_path(root, rel, pathkeys, required_outer));
6371 3118 : 2372 : }
3119 : :
3120 : : /*
3121 : : * set_namedtuplestore_pathlist
3122 : : * Build the (single) access path for a named tuplestore RTE
3123 : : *
3124 : : * There's no need for a separate set_namedtuplestore_size phase, since we
3125 : : * don't support join-qual-parameterized paths for tuplestores.
3126 : : */
3127 : : static void
3271 kgrittn@postgresql.o 3128 : 241 : set_namedtuplestore_pathlist(PlannerInfo *root, RelOptInfo *rel,
3129 : : RangeTblEntry *rte)
3130 : : {
3131 : : Relids required_outer;
3132 : :
3133 : : /* Mark rel with estimated output rows, width, etc */
3134 : 241 : set_namedtuplestore_size_estimates(root, rel);
3135 : :
3136 : : /*
3137 : : * We don't support pushing join clauses into the quals of a tuplestore
3138 : : * scan, but it could still have required parameterization due to LATERAL
3139 : : * refs in its tlist.
3140 : : */
3141 : 241 : required_outer = rel->lateral_relids;
3142 : :
3143 : : /* Generate appropriate path */
3144 : 241 : add_path(rel, create_namedtuplestorescan_path(root, rel, required_outer));
3145 : 241 : }
3146 : :
3147 : : /*
3148 : : * set_result_pathlist
3149 : : * Build the (single) access path for an RTE_RESULT RTE
3150 : : *
3151 : : * There's no need for a separate set_result_size phase, since we
3152 : : * don't support join-qual-parameterized paths for these RTEs.
3153 : : */
3154 : : static void
2603 tgl@sss.pgh.pa.us 3155 : 2172 : set_result_pathlist(PlannerInfo *root, RelOptInfo *rel,
3156 : : RangeTblEntry *rte)
3157 : : {
3158 : : Relids required_outer;
3159 : :
3160 : : /* Mark rel with estimated output rows, width, etc */
3161 : 2172 : set_result_size_estimates(root, rel);
3162 : :
3163 : : /*
3164 : : * We don't support pushing join clauses into the quals of a Result scan,
3165 : : * but it could still have required parameterization due to LATERAL refs
3166 : : * in its tlist.
3167 : : */
3168 : 2172 : required_outer = rel->lateral_relids;
3169 : :
3170 : : /* Generate appropriate path */
3171 : 2172 : add_path(rel, create_resultscan_path(root, rel, required_outer));
3172 : 2172 : }
3173 : :
3174 : : /*
3175 : : * set_worktable_pathlist
3176 : : * Build the (single) access path for a self-reference CTE RTE
3177 : : *
3178 : : * There's no need for a separate set_worktable_size phase, since we don't
3179 : : * support join-qual-parameterized paths for CTEs.
3180 : : */
3181 : : static void
6371 3182 : 543 : set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
3183 : : {
3184 : : Path *ctepath;
3185 : : PlannerInfo *cteroot;
3186 : : Index levelsup;
3187 : : Relids required_outer;
3188 : :
3189 : : /*
3190 : : * We need to find the non-recursive term's path, which is in the plan
3191 : : * level that's processing the recursive UNION, which is one level *below*
3192 : : * where the CTE comes from.
3193 : : */
3194 : 543 : levelsup = rte->ctelevelsup;
3195 [ - + ]: 543 : if (levelsup == 0) /* shouldn't happen */
6371 tgl@sss.pgh.pa.us 3196 [ # # ]:UBC 0 : elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
6371 tgl@sss.pgh.pa.us 3197 :CBC 543 : levelsup--;
3198 : 543 : cteroot = root;
3199 [ + + ]: 1300 : while (levelsup-- > 0)
3200 : : {
3201 : 757 : cteroot = cteroot->parent_root;
3202 [ - + ]: 757 : if (!cteroot) /* shouldn't happen */
6371 tgl@sss.pgh.pa.us 3203 [ # # ]:UBC 0 : elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
3204 : : }
3660 tgl@sss.pgh.pa.us 3205 :CBC 543 : ctepath = cteroot->non_recursive_path;
3206 [ - + ]: 543 : if (!ctepath) /* shouldn't happen */
3660 tgl@sss.pgh.pa.us 3207 [ # # ]:UBC 0 : elog(ERROR, "could not find path for CTE \"%s\"", rte->ctename);
3208 : :
3209 : : /* Mark rel with estimated output rows, width, etc */
3660 tgl@sss.pgh.pa.us 3210 :CBC 543 : set_cte_size_estimates(root, rel, ctepath->rows);
3211 : :
3212 : : /*
3213 : : * We don't support pushing join clauses into the quals of a worktable
3214 : : * scan, but it could still have required parameterization due to LATERAL
3215 : : * refs in its tlist. (I'm not sure this is actually possible given the
3216 : : * restrictions on recursive references, but it's easy enough to support.)
3217 : : */
4949 3218 : 543 : required_outer = rel->lateral_relids;
3219 : :
3220 : : /* Generate appropriate path */
3221 : 543 : add_path(rel, create_worktablescan_path(root, rel, required_outer));
6371 3222 : 543 : }
3223 : :
3224 : : /*
3225 : : * generate_gather_paths
3226 : : * Generate parallel access paths for a relation by pushing a Gather or
3227 : : * Gather Merge on top of a partial path.
3228 : : *
3229 : : * This must not be called until after we're done creating all partial paths
3230 : : * for the specified relation. (Otherwise, add_partial_path might delete a
3231 : : * path that some GatherPath or GatherMergePath has a reference to.)
3232 : : *
3233 : : * If we're generating paths for a scan or join relation, override_rows will
3234 : : * be false, and we'll just use the relation's size estimate. When we're
3235 : : * being called for a partially-grouped or partially-distinct path, though, we
3236 : : * need to override the rowcount estimate. (It's not clear that the
3237 : : * particular value we're using here is actually best, but the underlying rel
3238 : : * has no estimate so we must do something.)
3239 : : */
3240 : : void
2939 rhaas@postgresql.org 3241 : 13542 : generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
3242 : : {
3243 : : Path *cheapest_partial_path;
3244 : : Path *simple_gather_path;
3245 : : ListCell *lc;
3246 : : double rows;
3247 : 13542 : double *rowsp = NULL;
3248 : :
3249 : : /* If there are no partial paths, there's nothing to do here. */
3707 3250 [ - + ]: 13542 : if (rel->partial_pathlist == NIL)
3707 rhaas@postgresql.org 3251 :UBC 0 : return;
3252 : :
3253 : : /* Should we override the rel's rowcount estimate? */
2939 rhaas@postgresql.org 3254 [ + + ]:CBC 13542 : if (override_rows)
3255 : 3486 : rowsp = &rows;
3256 : :
3257 : : /*
3258 : : * The output of Gather is always unsorted, so there's only one partial
3259 : : * path of interest: the cheapest one. That will be the one at the front
3260 : : * of partial_pathlist because of the way add_partial_path works.
3261 : : */
3707 3262 : 13542 : cheapest_partial_path = linitial(rel->partial_pathlist);
600 rguo@postgresql.org 3263 : 13542 : rows = compute_gather_rows(cheapest_partial_path);
3264 : : simple_gather_path = (Path *)
3646 rhaas@postgresql.org 3265 : 13542 : create_gather_path(root, rel, cheapest_partial_path, rel->reltarget,
3266 : : NULL, rowsp);
3707 3267 : 13542 : add_path(rel, simple_gather_path);
3268 : :
3269 : : /*
3270 : : * For each useful ordering, we can consider an order-preserving Gather
3271 : : * Merge.
3272 : : */
3224 bruce@momjian.us 3273 [ + - + + : 30213 : foreach(lc, rel->partial_pathlist)
+ + ]
3274 : : {
3275 : 16671 : Path *subpath = (Path *) lfirst(lc);
3276 : : GatherMergePath *path;
3277 : :
3293 rhaas@postgresql.org 3278 [ + + ]: 16671 : if (subpath->pathkeys == NIL)
3279 : 13203 : continue;
3280 : :
600 rguo@postgresql.org 3281 : 3468 : rows = compute_gather_rows(subpath);
3293 rhaas@postgresql.org 3282 : 3468 : path = create_gather_merge_path(root, rel, subpath, rel->reltarget,
3283 : : subpath->pathkeys, NULL, rowsp);
3284 : 3468 : add_path(rel, &path->path);
3285 : : }
3286 : : }
3287 : :
3288 : : /*
3289 : : * get_useful_pathkeys_for_relation
3290 : : * Determine which orderings of a relation might be useful.
3291 : : *
3292 : : * Getting data in sorted order can be useful either because the requested
3293 : : * order matches the final output ordering for the overall query we're
3294 : : * planning, or because it enables an efficient merge join. Here, we try
3295 : : * to figure out which pathkeys to consider.
3296 : : *
3297 : : * This allows us to do incremental sort on top of an index scan under a gather
3298 : : * merge node, i.e. parallelized.
3299 : : *
3300 : : * If the require_parallel_safe is true, we also require the expressions to
3301 : : * be parallel safe (which allows pushing the sort below Gather Merge).
3302 : : *
3303 : : * XXX At the moment this can only ever return a list with a single element,
3304 : : * because it looks at query_pathkeys only. So we might return the pathkeys
3305 : : * directly, but it seems plausible we'll want to consider other orderings
3306 : : * in the future. For example, we might want to consider pathkeys useful for
3307 : : * merge joins.
3308 : : */
3309 : : static List *
1910 tomas.vondra@postgre 3310 : 13542 : get_useful_pathkeys_for_relation(PlannerInfo *root, RelOptInfo *rel,
3311 : : bool require_parallel_safe)
3312 : : {
2168 3313 : 13542 : List *useful_pathkeys_list = NIL;
3314 : :
3315 : : /*
3316 : : * Considering query_pathkeys is always worth it, because it might allow
3317 : : * us to avoid a total sort when we have a partially presorted path
3318 : : * available or to push the total sort into the parallel portion of the
3319 : : * query.
3320 : : */
3321 [ + + ]: 13542 : if (root->query_pathkeys)
3322 : : {
3323 : : ListCell *lc;
2131 tgl@sss.pgh.pa.us 3324 : 7775 : int npathkeys = 0; /* useful pathkeys */
3325 : :
2168 tomas.vondra@postgre 3326 [ + - + + : 13803 : foreach(lc, root->query_pathkeys)
+ + ]
3327 : : {
3328 : 9983 : PathKey *pathkey = (PathKey *) lfirst(lc);
3329 : 9983 : EquivalenceClass *pathkey_ec = pathkey->pk_eclass;
3330 : :
3331 : : /*
3332 : : * We can only build a sort for pathkeys that contain a
3333 : : * safe-to-compute-early EC member computable from the current
3334 : : * relation's reltarget, so ignore the remainder of the list as
3335 : : * soon as we find a pathkey without such a member.
3336 : : *
3337 : : * It's still worthwhile to return any prefix of the pathkeys list
3338 : : * that meets this requirement, as we may be able to do an
3339 : : * incremental sort.
3340 : : *
3341 : : * If requested, ensure the sort expression is parallel-safe too.
3342 : : */
1790 tgl@sss.pgh.pa.us 3343 [ + + ]: 9983 : if (!relation_can_be_sorted_early(root, rel, pathkey_ec,
3344 : : require_parallel_safe))
2168 tomas.vondra@postgre 3345 : 3955 : break;
3346 : :
3347 : 6028 : npathkeys++;
3348 : : }
3349 : :
3350 : : /*
3351 : : * The whole query_pathkeys list matches, so append it directly, to
3352 : : * allow comparing pathkeys easily by comparing list pointer. If we
3353 : : * have to truncate the pathkeys, we gotta do a copy though.
3354 : : */
3355 [ + + ]: 7775 : if (npathkeys == list_length(root->query_pathkeys))
3356 : 3820 : useful_pathkeys_list = lappend(useful_pathkeys_list,
3357 : 3820 : root->query_pathkeys);
3358 [ + + ]: 3955 : else if (npathkeys > 0)
3359 : 237 : useful_pathkeys_list = lappend(useful_pathkeys_list,
1341 drowley@postgresql.o 3360 : 237 : list_copy_head(root->query_pathkeys,
3361 : : npathkeys));
3362 : : }
3363 : :
2168 tomas.vondra@postgre 3364 : 13542 : return useful_pathkeys_list;
3365 : : }
3366 : :
3367 : : /*
3368 : : * generate_useful_gather_paths
3369 : : * Generate parallel access paths for a relation by pushing a Gather or
3370 : : * Gather Merge on top of a partial path.
3371 : : *
3372 : : * Unlike plain generate_gather_paths, this looks both at pathkeys of input
3373 : : * paths (aiming to preserve the ordering), but also considers ordering that
3374 : : * might be useful for nodes above the gather merge node, and tries to add
3375 : : * a sort (regular or incremental) to provide that.
3376 : : */
3377 : : void
3378 : 353213 : generate_useful_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
3379 : : {
3380 : : ListCell *lc;
3381 : : double rows;
3382 : 353213 : double *rowsp = NULL;
3383 : 353213 : List *useful_pathkeys_list = NIL;
3384 : 353213 : Path *cheapest_partial_path = NULL;
3385 : :
3386 : : /* If there are no partial paths, there's nothing to do here. */
3387 [ + + ]: 353213 : if (rel->partial_pathlist == NIL)
3388 : 339671 : return;
3389 : :
3390 : : /* Should we override the rel's rowcount estimate? */
3391 [ + + ]: 13542 : if (override_rows)
3392 : 3486 : rowsp = &rows;
3393 : :
3394 : : /* generate the regular gather (merge) paths */
3395 : 13542 : generate_gather_paths(root, rel, override_rows);
3396 : :
3397 : : /* consider incremental sort for interesting orderings */
1910 3398 : 13542 : useful_pathkeys_list = get_useful_pathkeys_for_relation(root, rel, true);
3399 : :
3400 : : /* used for explicit (full) sort paths */
2168 3401 : 13542 : cheapest_partial_path = linitial(rel->partial_pathlist);
3402 : :
3403 : : /*
3404 : : * Consider sorted paths for each interesting ordering. We generate both
3405 : : * incremental and full sort.
3406 : : */
3407 [ + + + + : 17599 : foreach(lc, useful_pathkeys_list)
+ + ]
3408 : : {
3409 : 4057 : List *useful_pathkeys = lfirst(lc);
3410 : : ListCell *lc2;
3411 : : bool is_sorted;
3412 : : int presorted_keys;
3413 : :
3414 [ + - + + : 9574 : foreach(lc2, rel->partial_pathlist)
+ + ]
3415 : : {
3416 : 5517 : Path *subpath = (Path *) lfirst(lc2);
3417 : : GatherMergePath *path;
3418 : :
3419 : 5517 : is_sorted = pathkeys_count_contained_in(useful_pathkeys,
3420 : : subpath->pathkeys,
3421 : : &presorted_keys);
3422 : :
3423 : : /*
3424 : : * We don't need to consider the case where a subpath is already
3425 : : * fully sorted because generate_gather_paths already creates a
3426 : : * gather merge path for every subpath that has pathkeys present.
3427 : : *
3428 : : * But since the subpath is already sorted, we know we don't need
3429 : : * to consider adding a sort (full or incremental) on top of it,
3430 : : * so we can continue here.
3431 : : */
3432 [ + + ]: 5517 : if (is_sorted)
3433 : 1518 : continue;
3434 : :
3435 : : /*
3436 : : * Try at least sorting the cheapest path and also try
3437 : : * incrementally sorting any path which is partially sorted
3438 : : * already (no need to deal with paths which have presorted keys
3439 : : * when incremental sort is disabled unless it's the cheapest
3440 : : * input path).
3441 : : */
1185 drowley@postgresql.o 3442 [ + + ]: 3999 : if (subpath != cheapest_partial_path &&
3443 [ + + + + ]: 189 : (presorted_keys == 0 || !enable_incremental_sort))
3444 : 51 : continue;
3445 : :
3446 : : /*
3447 : : * Consider regular sort for any path that's not presorted or if
3448 : : * incremental sort is disabled. We've no need to consider both
3449 : : * sort and incremental sort on the same path. We assume that
3450 : : * incremental sort is always faster when there are presorted
3451 : : * keys.
3452 : : *
3453 : : * This is not redundant with the gather paths created in
3454 : : * generate_gather_paths, because that doesn't generate ordered
3455 : : * output. Here we add an explicit sort to match the useful
3456 : : * ordering.
3457 : : */
3458 [ + + + + ]: 3948 : if (presorted_keys == 0 || !enable_incremental_sort)
3459 : : {
3460 : 3804 : subpath = (Path *) create_sort_path(root,
3461 : : rel,
3462 : : subpath,
3463 : : useful_pathkeys,
3464 : : -1.0);
3465 : : }
3466 : : else
3467 : 144 : subpath = (Path *) create_incremental_sort_path(root,
3468 : : rel,
3469 : : subpath,
3470 : : useful_pathkeys,
3471 : : presorted_keys,
3472 : : -1);
600 rguo@postgresql.org 3473 : 3948 : rows = compute_gather_rows(subpath);
1185 drowley@postgresql.o 3474 : 3948 : path = create_gather_merge_path(root, rel,
3475 : : subpath,
3476 : 3948 : rel->reltarget,
3477 : : subpath->pathkeys,
3478 : : NULL,
3479 : : rowsp);
3480 : :
3481 : 3948 : add_path(rel, &path->path);
3482 : : }
3483 : : }
3484 : : }
3485 : :
3486 : : /*
3487 : : * generate_grouped_paths
3488 : : * Generate paths for a grouped relation by adding sorted and hashed
3489 : : * partial aggregation paths on top of paths of the ungrouped relation.
3490 : : *
3491 : : * The information needed is provided by the RelAggInfo structure stored in
3492 : : * "grouped_rel".
3493 : : */
3494 : : void
158 rguo@postgresql.org 3495 :GNC 449 : generate_grouped_paths(PlannerInfo *root, RelOptInfo *grouped_rel,
3496 : : RelOptInfo *rel)
3497 : : {
3498 : 449 : RelAggInfo *agg_info = grouped_rel->agg_info;
3499 : : AggClauseCosts agg_costs;
3500 : : bool can_hash;
3501 : : bool can_sort;
3502 : 449 : Path *cheapest_total_path = NULL;
3503 : 449 : Path *cheapest_partial_path = NULL;
3504 : 449 : double dNumGroups = 0;
3505 : 449 : double dNumPartialGroups = 0;
3506 : 449 : List *group_pathkeys = NIL;
3507 : :
3508 [ - + ]: 449 : if (IS_DUMMY_REL(rel))
3509 : : {
158 rguo@postgresql.org 3510 :UNC 0 : mark_dummy_rel(grouped_rel);
3511 : 0 : return;
3512 : : }
3513 : :
3514 : : /*
3515 : : * We push partial aggregation only to the lowest possible level in the
3516 : : * join tree that is deemed useful.
3517 : : */
152 rguo@postgresql.org 3518 [ + - ]:GNC 449 : if (!bms_equal(agg_info->apply_agg_at, rel->relids) ||
158 3519 [ - + ]: 449 : !agg_info->agg_useful)
158 rguo@postgresql.org 3520 :UNC 0 : return;
3521 : :
158 rguo@postgresql.org 3522 [ + - + - :GNC 2694 : MemSet(&agg_costs, 0, sizeof(AggClauseCosts));
+ - + - +
+ ]
3523 : 449 : get_agg_clause_costs(root, AGGSPLIT_INITIAL_SERIAL, &agg_costs);
3524 : :
3525 : : /*
3526 : : * Determine whether it's possible to perform sort-based implementations
3527 : : * of grouping, and generate the pathkeys that represent the grouping
3528 : : * requirements in that case.
3529 : : */
3530 : 449 : can_sort = grouping_is_sortable(agg_info->group_clauses);
3531 [ + - ]: 449 : if (can_sort)
3532 : : {
3533 : : RelOptInfo *top_grouped_rel;
3534 : : List *top_group_tlist;
3535 : :
3536 [ + + - + ]: 251 : top_grouped_rel = IS_OTHER_REL(rel) ?
3537 [ + + ]: 700 : rel->top_parent->grouped_rel : grouped_rel;
3538 : : top_group_tlist =
3539 : 449 : make_tlist_from_pathtarget(top_grouped_rel->agg_info->target);
3540 : :
3541 : : group_pathkeys =
3542 : 449 : make_pathkeys_for_sortclauses(root, agg_info->group_clauses,
3543 : : top_group_tlist);
3544 : : }
3545 : :
3546 : : /*
3547 : : * Determine whether we should consider hash-based implementations of
3548 : : * grouping.
3549 : : */
3550 [ - + ]: 449 : Assert(root->numOrderedAggs == 0);
3551 [ + - + - ]: 898 : can_hash = (agg_info->group_clauses != NIL &&
3552 : 449 : grouping_is_hashable(agg_info->group_clauses));
3553 : :
3554 : : /*
3555 : : * Consider whether we should generate partially aggregated non-partial
3556 : : * paths. We can only do this if we have a non-partial path.
3557 : : */
3558 [ + - ]: 449 : if (rel->pathlist != NIL)
3559 : : {
3560 : 449 : cheapest_total_path = rel->cheapest_total_path;
3561 [ - + ]: 449 : Assert(cheapest_total_path != NULL);
3562 : : }
3563 : :
3564 : : /*
3565 : : * If parallelism is possible for grouped_rel, then we should consider
3566 : : * generating partially-grouped partial paths. However, if the ungrouped
3567 : : * rel has no partial paths, then we can't.
3568 : : */
3569 [ + + + + ]: 449 : if (grouped_rel->consider_parallel && rel->partial_pathlist != NIL)
3570 : : {
3571 : 366 : cheapest_partial_path = linitial(rel->partial_pathlist);
3572 [ - + ]: 366 : Assert(cheapest_partial_path != NULL);
3573 : : }
3574 : :
3575 : : /* Estimate number of partial groups. */
3576 [ + - ]: 449 : if (cheapest_total_path != NULL)
3577 : 449 : dNumGroups = estimate_num_groups(root,
3578 : : agg_info->group_exprs,
3579 : : cheapest_total_path->rows,
3580 : : NULL, NULL);
3581 [ + + ]: 449 : if (cheapest_partial_path != NULL)
3582 : 366 : dNumPartialGroups = estimate_num_groups(root,
3583 : : agg_info->group_exprs,
3584 : : cheapest_partial_path->rows,
3585 : : NULL, NULL);
3586 : :
3587 [ + - + - ]: 449 : if (can_sort && cheapest_total_path != NULL)
3588 : : {
3589 : : ListCell *lc;
3590 : :
3591 : : /*
3592 : : * Use any available suitably-sorted path as input, and also consider
3593 : : * sorting the cheapest-total path and incremental sort on any paths
3594 : : * with presorted keys.
3595 : : *
3596 : : * To save planning time, we ignore parameterized input paths unless
3597 : : * they are the cheapest-total path.
3598 : : */
3599 [ + - + + : 1087 : foreach(lc, rel->pathlist)
+ + ]
3600 : : {
3601 : 638 : Path *input_path = (Path *) lfirst(lc);
3602 : : Path *path;
3603 : : bool is_sorted;
3604 : : int presorted_keys;
3605 : :
3606 : : /*
3607 : : * Ignore parameterized paths that are not the cheapest-total
3608 : : * path.
3609 : : */
3610 [ + + + - ]: 638 : if (input_path->param_info &&
3611 : : input_path != cheapest_total_path)
3612 : 15 : continue;
3613 : :
3614 : 635 : is_sorted = pathkeys_count_contained_in(group_pathkeys,
3615 : : input_path->pathkeys,
3616 : : &presorted_keys);
3617 : :
3618 : : /*
3619 : : * Ignore paths that are not suitably or partially sorted, unless
3620 : : * they are the cheapest total path (no need to deal with paths
3621 : : * which have presorted keys when incremental sort is disabled).
3622 : : */
3623 [ + + + + ]: 635 : if (!is_sorted && input_path != cheapest_total_path &&
3624 [ + + - + ]: 84 : (presorted_keys == 0 || !enable_incremental_sort))
3625 : 12 : continue;
3626 : :
3627 : : /*
3628 : : * Since the path originates from a non-grouped relation that is
3629 : : * not aware of eager aggregation, we must ensure that it provides
3630 : : * the correct input for partial aggregation.
3631 : : */
3632 : 623 : path = (Path *) create_projection_path(root,
3633 : : grouped_rel,
3634 : : input_path,
3635 : 623 : agg_info->agg_input);
3636 : :
3637 [ + + ]: 623 : if (!is_sorted)
3638 : : {
3639 : : /*
3640 : : * We've no need to consider both a sort and incremental sort.
3641 : : * We'll just do a sort if there are no presorted keys and an
3642 : : * incremental sort when there are presorted keys.
3643 : : */
3644 [ + + - + ]: 518 : if (presorted_keys == 0 || !enable_incremental_sort)
3645 : 446 : path = (Path *) create_sort_path(root,
3646 : : grouped_rel,
3647 : : path,
3648 : : group_pathkeys,
3649 : : -1.0);
3650 : : else
3651 : 72 : path = (Path *) create_incremental_sort_path(root,
3652 : : grouped_rel,
3653 : : path,
3654 : : group_pathkeys,
3655 : : presorted_keys,
3656 : : -1.0);
3657 : : }
3658 : :
3659 : : /*
3660 : : * qual is NIL because the HAVING clause cannot be evaluated until
3661 : : * the final value of the aggregate is known.
3662 : : */
3663 : 623 : path = (Path *) create_agg_path(root,
3664 : : grouped_rel,
3665 : : path,
3666 : 623 : agg_info->target,
3667 : : AGG_SORTED,
3668 : : AGGSPLIT_INITIAL_SERIAL,
3669 : : agg_info->group_clauses,
3670 : : NIL,
3671 : : &agg_costs,
3672 : : dNumGroups);
3673 : :
3674 : 623 : add_path(grouped_rel, path);
3675 : : }
3676 : : }
3677 : :
3678 [ + - + + ]: 449 : if (can_sort && cheapest_partial_path != NULL)
3679 : : {
3680 : : ListCell *lc;
3681 : :
3682 : : /* Similar to above logic, but for partial paths. */
3683 [ + - + + : 852 : foreach(lc, rel->partial_pathlist)
+ + ]
3684 : : {
3685 : 486 : Path *input_path = (Path *) lfirst(lc);
3686 : : Path *path;
3687 : : bool is_sorted;
3688 : : int presorted_keys;
3689 : :
3690 : 486 : is_sorted = pathkeys_count_contained_in(group_pathkeys,
3691 : : input_path->pathkeys,
3692 : : &presorted_keys);
3693 : :
3694 : : /*
3695 : : * Ignore paths that are not suitably or partially sorted, unless
3696 : : * they are the cheapest partial path (no need to deal with paths
3697 : : * which have presorted keys when incremental sort is disabled).
3698 : : */
3699 [ + + + + ]: 486 : if (!is_sorted && input_path != cheapest_partial_path &&
3700 [ + - - + ]: 48 : (presorted_keys == 0 || !enable_incremental_sort))
158 rguo@postgresql.org 3701 :UNC 0 : continue;
3702 : :
3703 : : /*
3704 : : * Since the path originates from a non-grouped relation that is
3705 : : * not aware of eager aggregation, we must ensure that it provides
3706 : : * the correct input for partial aggregation.
3707 : : */
158 rguo@postgresql.org 3708 :GNC 486 : path = (Path *) create_projection_path(root,
3709 : : grouped_rel,
3710 : : input_path,
3711 : 486 : agg_info->agg_input);
3712 : :
3713 [ + + ]: 486 : if (!is_sorted)
3714 : : {
3715 : : /*
3716 : : * We've no need to consider both a sort and incremental sort.
3717 : : * We'll just do a sort if there are no presorted keys and an
3718 : : * incremental sort when there are presorted keys.
3719 : : */
3720 [ + + - + ]: 414 : if (presorted_keys == 0 || !enable_incremental_sort)
3721 : 366 : path = (Path *) create_sort_path(root,
3722 : : grouped_rel,
3723 : : path,
3724 : : group_pathkeys,
3725 : : -1.0);
3726 : : else
3727 : 48 : path = (Path *) create_incremental_sort_path(root,
3728 : : grouped_rel,
3729 : : path,
3730 : : group_pathkeys,
3731 : : presorted_keys,
3732 : : -1.0);
3733 : : }
3734 : :
3735 : : /*
3736 : : * qual is NIL because the HAVING clause cannot be evaluated until
3737 : : * the final value of the aggregate is known.
3738 : : */
3739 : 486 : path = (Path *) create_agg_path(root,
3740 : : grouped_rel,
3741 : : path,
3742 : 486 : agg_info->target,
3743 : : AGG_SORTED,
3744 : : AGGSPLIT_INITIAL_SERIAL,
3745 : : agg_info->group_clauses,
3746 : : NIL,
3747 : : &agg_costs,
3748 : : dNumPartialGroups);
3749 : :
3750 : 486 : add_partial_path(grouped_rel, path);
3751 : : }
3752 : : }
3753 : :
3754 : : /*
3755 : : * Add a partially-grouped HashAgg Path where possible
3756 : : */
3757 [ + - + - ]: 449 : if (can_hash && cheapest_total_path != NULL)
3758 : : {
3759 : : Path *path;
3760 : :
3761 : : /*
3762 : : * Since the path originates from a non-grouped relation that is not
3763 : : * aware of eager aggregation, we must ensure that it provides the
3764 : : * correct input for partial aggregation.
3765 : : */
3766 : 449 : path = (Path *) create_projection_path(root,
3767 : : grouped_rel,
3768 : : cheapest_total_path,
3769 : 449 : agg_info->agg_input);
3770 : :
3771 : : /*
3772 : : * qual is NIL because the HAVING clause cannot be evaluated until the
3773 : : * final value of the aggregate is known.
3774 : : */
3775 : 449 : path = (Path *) create_agg_path(root,
3776 : : grouped_rel,
3777 : : path,
3778 : 449 : agg_info->target,
3779 : : AGG_HASHED,
3780 : : AGGSPLIT_INITIAL_SERIAL,
3781 : : agg_info->group_clauses,
3782 : : NIL,
3783 : : &agg_costs,
3784 : : dNumGroups);
3785 : :
3786 : 449 : add_path(grouped_rel, path);
3787 : : }
3788 : :
3789 : : /*
3790 : : * Now add a partially-grouped HashAgg partial Path where possible
3791 : : */
3792 [ + - + + ]: 449 : if (can_hash && cheapest_partial_path != NULL)
3793 : : {
3794 : : Path *path;
3795 : :
3796 : : /*
3797 : : * Since the path originates from a non-grouped relation that is not
3798 : : * aware of eager aggregation, we must ensure that it provides the
3799 : : * correct input for partial aggregation.
3800 : : */
3801 : 366 : path = (Path *) create_projection_path(root,
3802 : : grouped_rel,
3803 : : cheapest_partial_path,
3804 : 366 : agg_info->agg_input);
3805 : :
3806 : : /*
3807 : : * qual is NIL because the HAVING clause cannot be evaluated until the
3808 : : * final value of the aggregate is known.
3809 : : */
3810 : 366 : path = (Path *) create_agg_path(root,
3811 : : grouped_rel,
3812 : : path,
3813 : 366 : agg_info->target,
3814 : : AGG_HASHED,
3815 : : AGGSPLIT_INITIAL_SERIAL,
3816 : : agg_info->group_clauses,
3817 : : NIL,
3818 : : &agg_costs,
3819 : : dNumPartialGroups);
3820 : :
3821 : 366 : add_partial_path(grouped_rel, path);
3822 : : }
3823 : : }
3824 : :
3825 : : /*
3826 : : * make_rel_from_joinlist
3827 : : * Build access paths using a "joinlist" to guide the join path search.
3828 : : *
3829 : : * See comments for deconstruct_jointree() for definition of the joinlist
3830 : : * data structure.
3831 : : */
3832 : : static RelOptInfo *
7390 tgl@sss.pgh.pa.us 3833 :CBC 186414 : make_rel_from_joinlist(PlannerInfo *root, List *joinlist)
3834 : : {
3835 : : int levels_needed;
3836 : : List *initial_rels;
3837 : : ListCell *jl;
3838 : :
3839 : : /*
3840 : : * Count the number of child joinlist nodes. This is the depth of the
3841 : : * dynamic-programming algorithm we must employ to consider all ways of
3842 : : * joining the child nodes.
3843 : : */
3844 : 186414 : levels_needed = list_length(joinlist);
3845 : :
9298 3846 [ - + ]: 186414 : if (levels_needed <= 0)
9298 tgl@sss.pgh.pa.us 3847 :UBC 0 : return NULL; /* nothing to do? */
3848 : :
3849 : : /*
3850 : : * Construct a list of rels corresponding to the child joinlist nodes.
3851 : : * This may contain both base rels and rels constructed according to
3852 : : * sub-joinlists.
3853 : : */
7390 tgl@sss.pgh.pa.us 3854 :CBC 186414 : initial_rels = NIL;
3855 [ + - + + : 452889 : foreach(jl, joinlist)
+ + ]
3856 : : {
3857 : 266475 : Node *jlnode = (Node *) lfirst(jl);
3858 : : RelOptInfo *thisrel;
3859 : :
3860 [ + + ]: 266475 : if (IsA(jlnode, RangeTblRef))
3861 : : {
3862 : 264729 : int varno = ((RangeTblRef *) jlnode)->rtindex;
3863 : :
3864 : 264729 : thisrel = find_base_rel(root, varno);
3865 : : }
3866 [ + - ]: 1746 : else if (IsA(jlnode, List))
3867 : : {
3868 : : /* Recurse to handle subproblem */
3869 : 1746 : thisrel = make_rel_from_joinlist(root, (List *) jlnode);
3870 : : }
3871 : : else
3872 : : {
7390 tgl@sss.pgh.pa.us 3873 [ # # ]:UBC 0 : elog(ERROR, "unrecognized joinlist node type: %d",
3874 : : (int) nodeTag(jlnode));
3875 : : thisrel = NULL; /* keep compiler quiet */
3876 : : }
3877 : :
7390 tgl@sss.pgh.pa.us 3878 :CBC 266475 : initial_rels = lappend(initial_rels, thisrel);
3879 : : }
3880 : :
9298 3881 [ + + ]: 186414 : if (levels_needed == 1)
3882 : : {
3883 : : /*
3884 : : * Single joinlist node, so we're done.
3885 : : */
7963 neilc@samurai.com 3886 : 128403 : return (RelOptInfo *) linitial(initial_rels);
3887 : : }
3888 : : else
3889 : : {
3890 : : /*
3891 : : * Consider the different orders in which we could join the rels,
3892 : : * using a plugin, GEQO, or the regular join search code.
3893 : : *
3894 : : * We put the initial_rels list into a PlannerInfo field because
3895 : : * has_legal_joinclause() needs to look at it (ugly :-().
3896 : : */
6638 tgl@sss.pgh.pa.us 3897 : 58011 : root->initial_rels = initial_rels;
3898 : :
6745 3899 [ - + ]: 58011 : if (join_search_hook)
6745 tgl@sss.pgh.pa.us 3900 :UBC 0 : return (*join_search_hook) (root, levels_needed, initial_rels);
6745 tgl@sss.pgh.pa.us 3901 [ + - + + ]:CBC 58011 : else if (enable_geqo && levels_needed >= geqo_threshold)
9298 3902 : 21 : return geqo(root, levels_needed, initial_rels);
3903 : : else
6745 3904 : 57990 : return standard_join_search(root, levels_needed, initial_rels);
3905 : : }
3906 : : }
3907 : :
3908 : : /*
3909 : : * standard_join_search
3910 : : * Find possible joinpaths for a query by successively finding ways
3911 : : * to join component relations into join relations.
3912 : : *
3913 : : * 'levels_needed' is the number of iterations needed, ie, the number of
3914 : : * independent jointree items in the query. This is > 1.
3915 : : *
3916 : : * 'initial_rels' is a list of RelOptInfo nodes for each independent
3917 : : * jointree item. These are the components to be joined together.
3918 : : * Note that levels_needed == list_length(initial_rels).
3919 : : *
3920 : : * Returns the final level of join relations, i.e., the relation that is
3921 : : * the result of joining all the original relations together.
3922 : : * At least one implementation path must be provided for this relation and
3923 : : * all required sub-relations.
3924 : : *
3925 : : * To support loadable plugins that modify planner behavior by changing the
3926 : : * join searching algorithm, we provide a hook variable that lets a plugin
3927 : : * replace or supplement this function. Any such hook must return the same
3928 : : * final join relation as the standard code would, but it might have a
3929 : : * different set of implementation paths attached, and only the sub-joinrels
3930 : : * needed for these paths need have been instantiated.
3931 : : *
3932 : : * Note to plugin authors: the functions invoked during standard_join_search()
3933 : : * modify root->join_rel_list and root->join_rel_hash. If you want to do more
3934 : : * than one join-order search, you'll probably need to save and restore the
3935 : : * original states of those data structures. See geqo_eval() for an example.
3936 : : */
3937 : : RelOptInfo *
3938 : 57990 : standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels)
3939 : : {
3940 : : int lev;
3941 : : RelOptInfo *rel;
3942 : :
3943 : : /*
3944 : : * This function cannot be invoked recursively within any one planning
3945 : : * problem, so join_rel_level[] can't be in use already.
3946 : : */
5951 3947 [ - + ]: 57990 : Assert(root->join_rel_level == NULL);
3948 : :
3949 : : /*
3950 : : * We employ a simple "dynamic programming" algorithm: we first find all
3951 : : * ways to build joins of two jointree items, then all ways to build joins
3952 : : * of three items (from two-item joins and single items), then four-item
3953 : : * joins, and so on until we have considered all ways to join all the
3954 : : * items into one rel.
3955 : : *
3956 : : * root->join_rel_level[j] is a list of all the j-item rels. Initially we
3957 : : * set root->join_rel_level[1] to represent all the single-jointree-item
3958 : : * relations.
3959 : : */
3960 : 57990 : root->join_rel_level = (List **) palloc0((levels_needed + 1) * sizeof(List *));
3961 : :
3962 : 57990 : root->join_rel_level[1] = initial_rels;
3963 : :
9533 3964 [ + + ]: 138021 : for (lev = 2; lev <= levels_needed; lev++)
3965 : : {
3966 : : ListCell *lc;
3967 : :
3968 : : /*
3969 : : * Determine all possible pairs of relations to be joined at this
3970 : : * level, and build paths for making each one from every available
3971 : : * pair of lower-level relations.
3972 : : */
5951 3973 : 80031 : join_search_one_level(root, lev);
3974 : :
3975 : : /*
3976 : : * Run generate_partitionwise_join_paths() and
3977 : : * generate_useful_gather_paths() for each just-processed joinrel. We
3978 : : * could not do this earlier because both regular and partial paths
3979 : : * can get added to a particular joinrel at multiple times within
3980 : : * join_search_one_level.
3981 : : *
3982 : : * After that, we're done creating paths for the joinrel, so run
3983 : : * set_cheapest().
3984 : : *
3985 : : * In addition, we also run generate_grouped_paths() for the grouped
3986 : : * relation of each just-processed joinrel, and run set_cheapest() for
3987 : : * the grouped relation afterwards.
3988 : : */
3989 [ + + + + : 206567 : foreach(lc, root->join_rel_level[lev])
+ + ]
3990 : : {
3991 : : bool is_top_rel;
3992 : :
3993 : 126536 : rel = (RelOptInfo *) lfirst(lc);
3994 : :
158 rguo@postgresql.org 3995 :GNC 126536 : is_top_rel = bms_equal(rel->relids, root->all_query_rels);
3996 : :
3997 : : /* Create paths for partitionwise joins. */
2949 peter_e@gmx.net 3998 :CBC 126536 : generate_partitionwise_join_paths(root, rel);
3999 : :
4000 : : /*
4001 : : * Except for the topmost scan/join rel, consider gathering
4002 : : * partial paths. We'll do the same for the topmost scan/join rel
4003 : : * once we know the final targetlist (see grouping_planner's and
4004 : : * its call to apply_scanjoin_target_to_paths).
4005 : : */
158 rguo@postgresql.org 4006 [ + + ]:GNC 126536 : if (!is_top_rel)
2168 tomas.vondra@postgre 4007 :CBC 68801 : generate_useful_gather_paths(root, rel, false);
4008 : :
4009 : : /* Find and save the cheapest paths for this rel */
9525 tgl@sss.pgh.pa.us 4010 : 126536 : set_cheapest(rel);
4011 : :
4012 : : /*
4013 : : * Except for the topmost scan/join rel, consider generating
4014 : : * partial aggregation paths for the grouped relation on top of
4015 : : * the paths of this rel. After that, we're done creating paths
4016 : : * for the grouped relation, so run set_cheapest().
4017 : : */
158 rguo@postgresql.org 4018 [ + + + + ]:GNC 126536 : if (rel->grouped_rel != NULL && !is_top_rel)
4019 : : {
4020 : 36 : RelOptInfo *grouped_rel = rel->grouped_rel;
4021 : :
4022 [ - + ]: 36 : Assert(IS_GROUPED_REL(grouped_rel));
4023 : :
4024 : 36 : generate_grouped_paths(root, grouped_rel, rel);
4025 : 36 : set_cheapest(grouped_rel);
4026 : : }
4027 : :
4028 : : #ifdef OPTIMIZER_DEBUG
4029 : : pprint(rel);
4030 : : #endif
4031 : : }
4032 : : }
4033 : :
4034 : : /*
4035 : : * We should have a single rel at the final level.
4036 : : */
5951 tgl@sss.pgh.pa.us 4037 [ - + ]:CBC 57990 : if (root->join_rel_level[levels_needed] == NIL)
8124 tgl@sss.pgh.pa.us 4038 [ # # ]:UBC 0 : elog(ERROR, "failed to build any %d-way joins", levels_needed);
5951 tgl@sss.pgh.pa.us 4039 [ - + ]:CBC 57990 : Assert(list_length(root->join_rel_level[levels_needed]) == 1);
4040 : :
4041 : 57990 : rel = (RelOptInfo *) linitial(root->join_rel_level[levels_needed]);
4042 : :
4043 : 57990 : root->join_rel_level = NULL;
4044 : :
9533 4045 : 57990 : return rel;
4046 : : }
4047 : :
4048 : : /*****************************************************************************
4049 : : * PUSHING QUALS DOWN INTO SUBQUERIES
4050 : : *****************************************************************************/
4051 : :
4052 : : /*
4053 : : * subquery_is_pushdown_safe - is a subquery safe for pushing down quals?
4054 : : *
4055 : : * subquery is the particular component query being checked. topquery
4056 : : * is the top component of a set-operations tree (the same Query if no
4057 : : * set-op is involved).
4058 : : *
4059 : : * Conditions checked here:
4060 : : *
4061 : : * 1. If the subquery has a LIMIT clause, we must not push down any quals,
4062 : : * since that could change the set of rows returned.
4063 : : *
4064 : : * 2. If the subquery contains EXCEPT or EXCEPT ALL set ops we cannot push
4065 : : * quals into it, because that could change the results.
4066 : : *
4067 : : * 3. If the subquery uses DISTINCT, we cannot push volatile quals into it.
4068 : : * This is because upper-level quals should semantically be evaluated only
4069 : : * once per distinct row, not once per original row, and if the qual is
4070 : : * volatile then extra evaluations could change the results. (This issue
4071 : : * does not apply to other forms of aggregation such as GROUP BY, because
4072 : : * when those are present we push into HAVING not WHERE, so that the quals
4073 : : * are still applied after aggregation.)
4074 : : *
4075 : : * 4. If the subquery contains window functions, we cannot push volatile quals
4076 : : * into it. The issue here is a bit different from DISTINCT: a volatile qual
4077 : : * might succeed for some rows of a window partition and fail for others,
4078 : : * thereby changing the partition contents and thus the window functions'
4079 : : * results for rows that remain.
4080 : : *
4081 : : * 5. If the subquery contains any set-returning functions in its targetlist,
4082 : : * we cannot push volatile quals into it. That would push them below the SRFs
4083 : : * and thereby change the number of times they are evaluated. Also, a
4084 : : * volatile qual could succeed for some SRF output rows and fail for others,
4085 : : * a behavior that cannot occur if it's evaluated before SRF expansion.
4086 : : *
4087 : : * 6. If the subquery has nonempty grouping sets, we cannot push down any
4088 : : * quals. The concern here is that a qual referencing a "constant" grouping
4089 : : * column could get constant-folded, which would be improper because the value
4090 : : * is potentially nullable by grouping-set expansion. This restriction could
4091 : : * be removed if we had a parsetree representation that shows that such
4092 : : * grouping columns are not really constant. (There are other ideas that
4093 : : * could be used to relax this restriction, but that's the approach most
4094 : : * likely to get taken in the future. Note that there's not much to be gained
4095 : : * so long as subquery_planner can't move HAVING clauses to WHERE within such
4096 : : * a subquery.)
4097 : : *
4098 : : * In addition, we make several checks on the subquery's output columns to see
4099 : : * if it is safe to reference them in pushed-down quals. If output column k
4100 : : * is found to be unsafe to reference, we set the reason for that inside
4101 : : * safetyInfo->unsafeFlags[k], but we don't reject the subquery overall since
4102 : : * column k might not be referenced by some/all quals. The unsafeFlags[]
4103 : : * array will be consulted later by qual_is_pushdown_safe(). It's better to
4104 : : * do it this way than to make the checks directly in qual_is_pushdown_safe(),
4105 : : * because when the subquery involves set operations we have to check the
4106 : : * output expressions in each arm of the set op.
4107 : : *
4108 : : * Note: pushing quals into a DISTINCT subquery is theoretically dubious:
4109 : : * we're effectively assuming that the quals cannot distinguish values that
4110 : : * the DISTINCT's equality operator sees as equal, yet there are many
4111 : : * counterexamples to that assumption. However use of such a qual with a
4112 : : * DISTINCT subquery would be unsafe anyway, since there's no guarantee which
4113 : : * "equal" value will be chosen as the output value by the DISTINCT operation.
4114 : : * So we don't worry too much about that. Another objection is that if the
4115 : : * qual is expensive to evaluate, running it for each original row might cost
4116 : : * more than we save by eliminating rows before the DISTINCT step. But it
4117 : : * would be very hard to estimate that at this stage, and in practice pushdown
4118 : : * seldom seems to make things worse, so we ignore that problem too.
4119 : : *
4120 : : * Note: likewise, pushing quals into a subquery with window functions is a
4121 : : * bit dubious: the quals might remove some rows of a window partition while
4122 : : * leaving others, causing changes in the window functions' results for the
4123 : : * surviving rows. We insist that such a qual reference only partitioning
4124 : : * columns, but again that only protects us if the qual does not distinguish
4125 : : * values that the partitioning equality operator sees as equal. The risks
4126 : : * here are perhaps larger than for DISTINCT, since no de-duplication of rows
4127 : : * occurs and thus there is no theoretical problem with such a qual. But
4128 : : * we'll do this anyway because the potential performance benefits are very
4129 : : * large, and we've seen no field complaints about the longstanding comparable
4130 : : * behavior with DISTINCT.
4131 : : */
4132 : : static bool
8361 4133 : 1768 : subquery_is_pushdown_safe(Query *subquery, Query *topquery,
4134 : : pushdown_safety_info *safetyInfo)
4135 : : {
4136 : : SetOperationStmt *topop;
4137 : :
4138 : : /* Check point 1 */
8394 4139 [ + + + + ]: 1768 : if (subquery->limitOffset != NULL || subquery->limitCount != NULL)
8599 4140 : 67 : return false;
4141 : :
4142 : : /* Check point 6 */
2031 4143 [ + + + + ]: 1701 : if (subquery->groupClause && subquery->groupingSets)
4144 : 6 : return false;
4145 : :
4146 : : /* Check points 3, 4, and 5 */
3456 4147 [ + + ]: 1695 : if (subquery->distinctClause ||
4148 [ + + ]: 1653 : subquery->hasWindowFuncs ||
4149 [ + + ]: 1520 : subquery->hasTargetSRFs)
4279 4150 : 466 : safetyInfo->unsafeVolatile = true;
4151 : :
4152 : : /*
4153 : : * If we're at a leaf query, check for unsafe expressions in its target
4154 : : * list, and mark any reasons why they're unsafe in unsafeFlags[].
4155 : : * (Non-leaf nodes in setop trees have only simple Vars in their tlists,
4156 : : * so no need to check them.)
4157 : : */
4666 4158 [ + + ]: 1695 : if (subquery->setOperations == NULL)
4279 4159 : 1601 : check_output_expressions(subquery, safetyInfo);
4160 : :
4161 : : /* Are we at top level, or looking at a setop component? */
8599 4162 [ + + ]: 1695 : if (subquery == topquery)
4163 : : {
4164 : : /* Top level, so check any component queries */
4165 [ + + ]: 1507 : if (subquery->setOperations != NULL)
8361 4166 [ - + ]: 94 : if (!recurse_pushdown_safe(subquery->setOperations, topquery,
4167 : : safetyInfo))
8599 tgl@sss.pgh.pa.us 4168 :UBC 0 : return false;
4169 : : }
4170 : : else
4171 : : {
4172 : : /* Setop component must not have more components (too weird) */
8599 tgl@sss.pgh.pa.us 4173 [ - + ]:CBC 188 : if (subquery->setOperations != NULL)
8599 tgl@sss.pgh.pa.us 4174 :UBC 0 : return false;
4175 : : /* Check whether setop component output types match top level */
3309 peter_e@gmx.net 4176 :CBC 188 : topop = castNode(SetOperationStmt, topquery->setOperations);
4177 [ - + ]: 188 : Assert(topop);
8361 tgl@sss.pgh.pa.us 4178 : 188 : compare_tlist_datatypes(subquery->targetList,
4179 : : topop->colTypes,
4180 : : safetyInfo);
4181 : : }
8599 4182 : 1695 : return true;
4183 : : }
4184 : :
4185 : : /*
4186 : : * Helper routine to recurse through setOperations tree
4187 : : */
4188 : : static bool
8361 4189 : 282 : recurse_pushdown_safe(Node *setOp, Query *topquery,
4190 : : pushdown_safety_info *safetyInfo)
4191 : : {
8599 4192 [ + + ]: 282 : if (IsA(setOp, RangeTblRef))
4193 : : {
4194 : 188 : RangeTblRef *rtr = (RangeTblRef *) setOp;
4195 : 188 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, topquery->rtable);
4196 : 188 : Query *subquery = rte->subquery;
4197 : :
4198 [ - + ]: 188 : Assert(subquery != NULL);
4279 4199 : 188 : return subquery_is_pushdown_safe(subquery, topquery, safetyInfo);
4200 : : }
8599 4201 [ + - ]: 94 : else if (IsA(setOp, SetOperationStmt))
4202 : : {
4203 : 94 : SetOperationStmt *op = (SetOperationStmt *) setOp;
4204 : :
4205 : : /* EXCEPT is no good (point 2 for subquery_is_pushdown_safe) */
4206 [ - + ]: 94 : if (op->op == SETOP_EXCEPT)
8599 tgl@sss.pgh.pa.us 4207 :UBC 0 : return false;
4208 : : /* Else recurse */
4279 tgl@sss.pgh.pa.us 4209 [ - + ]:CBC 94 : if (!recurse_pushdown_safe(op->larg, topquery, safetyInfo))
8599 tgl@sss.pgh.pa.us 4210 :UBC 0 : return false;
4279 tgl@sss.pgh.pa.us 4211 [ - + ]:CBC 94 : if (!recurse_pushdown_safe(op->rarg, topquery, safetyInfo))
8599 tgl@sss.pgh.pa.us 4212 :UBC 0 : return false;
4213 : : }
4214 : : else
4215 : : {
8269 4216 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d",
4217 : : (int) nodeTag(setOp));
4218 : : }
8599 tgl@sss.pgh.pa.us 4219 :CBC 94 : return true;
4220 : : }
4221 : :
4222 : : /*
4223 : : * check_output_expressions - check subquery's output expressions for safety
4224 : : *
4225 : : * There are several cases in which it's unsafe to push down an upper-level
4226 : : * qual if it references a particular output column of a subquery. We check
4227 : : * each output column of the subquery and set flags in unsafeFlags[k] when we
4228 : : * see that column is unsafe for a pushed-down qual to reference. The
4229 : : * conditions checked here are:
4230 : : *
4231 : : * 1. We must not push down any quals that refer to subselect outputs that
4232 : : * return sets, else we'd introduce functions-returning-sets into the
4233 : : * subquery's WHERE/HAVING quals.
4234 : : *
4235 : : * 2. We must not push down any quals that refer to subselect outputs that
4236 : : * contain volatile functions, for fear of introducing strange results due
4237 : : * to multiple evaluation of a volatile function.
4238 : : *
4239 : : * 3. If the subquery uses DISTINCT ON, we must not push down any quals that
4240 : : * refer to non-DISTINCT output columns, because that could change the set
4241 : : * of rows returned. (This condition is vacuous for DISTINCT, because then
4242 : : * there are no non-DISTINCT output columns, so we needn't check. Note that
4243 : : * subquery_is_pushdown_safe already reported that we can't use volatile
4244 : : * quals if there's DISTINCT or DISTINCT ON.)
4245 : : *
4246 : : * 4. If the subquery has any window functions, we must not push down quals
4247 : : * that reference any output columns that are not listed in all the subquery's
4248 : : * window PARTITION BY clauses. We can push down quals that use only
4249 : : * partitioning columns because they should succeed or fail identically for
4250 : : * every row of any one window partition, and totally excluding some
4251 : : * partitions will not change a window function's results for remaining
4252 : : * partitions. (Again, this also requires nonvolatile quals, but
4253 : : * subquery_is_pushdown_safe handles that.). Subquery columns marked as
4254 : : * unsafe for this reason can still have WindowClause run conditions pushed
4255 : : * down.
4256 : : */
4257 : : static void
4279 4258 : 1601 : check_output_expressions(Query *subquery, pushdown_safety_info *safetyInfo)
4259 : : {
55 rguo@postgresql.org 4260 : 1601 : List *flattened_targetList = subquery->targetList;
4261 : : ListCell *lc;
4262 : :
4263 : : /*
4264 : : * We must be careful with grouping Vars and join alias Vars in the
4265 : : * subquery's outputs, as they hide the underlying expressions.
4266 : : *
4267 : : * We need to expand grouping Vars to their underlying expressions (the
4268 : : * grouping clauses) because the grouping expressions themselves might be
4269 : : * volatile or set-returning. However, we do not need to expand join
4270 : : * alias Vars, as their underlying structure does not introduce volatile
4271 : : * or set-returning functions at the current level.
4272 : : *
4273 : : * In neither case do we need to recursively examine the Vars contained in
4274 : : * these underlying expressions. Even if they reference outputs from
4275 : : * lower-level subqueries (at any depth), those references are guaranteed
4276 : : * not to expand to volatile or set-returning functions, because
4277 : : * subqueries containing such functions in their targetlists are never
4278 : : * pulled up.
4279 : : */
4280 [ + + ]: 1601 : if (subquery->hasGroupRTE)
4281 : : {
4282 : : /*
4283 : : * We can safely pass NULL for the root here. This function uses the
4284 : : * expanded expressions solely to check for volatile or set-returning
4285 : : * functions, which is independent of the Vars' nullingrels.
4286 : : */
4287 : : flattened_targetList = (List *)
4288 : 160 : flatten_group_exprs(NULL, subquery, (Node *) subquery->targetList);
4289 : : }
4290 : :
4291 [ + - + + : 18289 : foreach(lc, flattened_targetList)
+ + ]
4292 : : {
4666 tgl@sss.pgh.pa.us 4293 : 16688 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
4294 : :
4295 [ + + ]: 16688 : if (tle->resjunk)
4296 : 67 : continue; /* ignore resjunk columns */
4297 : :
4298 : : /* Functions returning sets are unsafe (point 1) */
3470 4299 [ + + ]: 16621 : if (subquery->hasTargetSRFs &&
1094 drowley@postgresql.o 4300 [ + - ]: 720 : (safetyInfo->unsafeFlags[tle->resno] &
4301 [ + + ]: 720 : UNSAFE_HAS_SET_FUNC) == 0 &&
3470 tgl@sss.pgh.pa.us 4302 : 720 : expression_returns_set((Node *) tle->expr))
4303 : : {
1094 drowley@postgresql.o 4304 : 568 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_HAS_SET_FUNC;
4666 tgl@sss.pgh.pa.us 4305 : 568 : continue;
4306 : : }
4307 : :
4308 : : /* Volatile functions are unsafe (point 2) */
1094 drowley@postgresql.o 4309 [ + + ]: 16053 : if ((safetyInfo->unsafeFlags[tle->resno] &
4310 [ + + ]: 16047 : UNSAFE_HAS_VOLATILE_FUNC) == 0 &&
4311 : 16047 : contain_volatile_functions((Node *) tle->expr))
4312 : : {
4313 : 45 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_HAS_VOLATILE_FUNC;
4666 tgl@sss.pgh.pa.us 4314 : 45 : continue;
4315 : : }
4316 : :
4317 : : /* If subquery uses DISTINCT ON, check point 3 */
4318 [ - + ]: 16008 : if (subquery->hasDistinctOn &&
1094 drowley@postgresql.o 4319 [ # # ]:UBC 0 : (safetyInfo->unsafeFlags[tle->resno] &
4320 : 0 : UNSAFE_NOTIN_DISTINCTON_CLAUSE) == 0 &&
4666 tgl@sss.pgh.pa.us 4321 [ # # ]: 0 : !targetIsInSortList(tle, InvalidOid, subquery->distinctClause))
4322 : : {
4323 : : /* non-DISTINCT column, so mark it unsafe */
1094 drowley@postgresql.o 4324 : 0 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_NOTIN_DISTINCTON_CLAUSE;
4666 tgl@sss.pgh.pa.us 4325 : 0 : continue;
4326 : : }
4327 : :
4328 : : /* If subquery uses window functions, check point 4 */
4279 tgl@sss.pgh.pa.us 4329 [ + + ]:CBC 16008 : if (subquery->hasWindowFuncs &&
1094 drowley@postgresql.o 4330 [ + - ]: 545 : (safetyInfo->unsafeFlags[tle->resno] &
4331 : 1046 : UNSAFE_NOTIN_DISTINCTON_CLAUSE) == 0 &&
4279 tgl@sss.pgh.pa.us 4332 [ + + ]: 545 : !targetIsInAllPartitionLists(tle, subquery))
4333 : : {
4334 : : /* not present in all PARTITION BY clauses, so mark it unsafe */
1094 drowley@postgresql.o 4335 : 501 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_NOTIN_PARTITIONBY_CLAUSE;
4279 tgl@sss.pgh.pa.us 4336 : 501 : continue;
4337 : : }
4338 : : }
4666 4339 : 1601 : }
4340 : :
4341 : : /*
4342 : : * For subqueries using UNION/UNION ALL/INTERSECT/INTERSECT ALL, we can
4343 : : * push quals into each component query, but the quals can only reference
4344 : : * subquery columns that suffer no type coercions in the set operation.
4345 : : * Otherwise there are possible semantic gotchas. So, we check the
4346 : : * component queries to see if any of them have output types different from
4347 : : * the top-level setop outputs. We set the UNSAFE_TYPE_MISMATCH bit in
4348 : : * unsafeFlags[k] if column k has different type in any component.
4349 : : *
4350 : : * We don't have to care about typmods here: the only allowed difference
4351 : : * between set-op input and output typmods is input is a specific typmod
4352 : : * and output is -1, and that does not require a coercion.
4353 : : *
4354 : : * tlist is a subquery tlist.
4355 : : * colTypes is an OID list of the top-level setop's output column types.
4356 : : * safetyInfo is the pushdown_safety_info to set unsafeFlags[] for.
4357 : : */
4358 : : static void
8361 4359 : 188 : compare_tlist_datatypes(List *tlist, List *colTypes,
4360 : : pushdown_safety_info *safetyInfo)
4361 : : {
4362 : : ListCell *l;
7963 neilc@samurai.com 4363 : 188 : ListCell *colType = list_head(colTypes);
4364 : :
4365 [ + - + + : 588 : foreach(l, tlist)
+ + ]
4366 : : {
4367 : 400 : TargetEntry *tle = (TargetEntry *) lfirst(l);
4368 : :
7648 tgl@sss.pgh.pa.us 4369 [ - + ]: 400 : if (tle->resjunk)
8361 tgl@sss.pgh.pa.us 4370 :UBC 0 : continue; /* ignore resjunk columns */
7963 neilc@samurai.com 4371 [ - + ]:CBC 400 : if (colType == NULL)
8361 tgl@sss.pgh.pa.us 4372 [ # # ]:UBC 0 : elog(ERROR, "wrong number of tlist entries");
7648 tgl@sss.pgh.pa.us 4373 [ + + ]:CBC 400 : if (exprType((Node *) tle->expr) != lfirst_oid(colType))
1094 drowley@postgresql.o 4374 : 68 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_TYPE_MISMATCH;
2435 tgl@sss.pgh.pa.us 4375 : 400 : colType = lnext(colTypes, colType);
4376 : : }
7963 neilc@samurai.com 4377 [ - + ]: 188 : if (colType != NULL)
8361 tgl@sss.pgh.pa.us 4378 [ # # ]:UBC 0 : elog(ERROR, "wrong number of tlist entries");
8361 tgl@sss.pgh.pa.us 4379 :CBC 188 : }
4380 : :
4381 : : /*
4382 : : * targetIsInAllPartitionLists
4383 : : * True if the TargetEntry is listed in the PARTITION BY clause
4384 : : * of every window defined in the query.
4385 : : *
4386 : : * It would be safe to ignore windows not actually used by any window
4387 : : * function, but it's not easy to get that info at this stage; and it's
4388 : : * unlikely to be useful to spend any extra cycles getting it, since
4389 : : * unreferenced window definitions are probably infrequent in practice.
4390 : : */
4391 : : static bool
4279 4392 : 545 : targetIsInAllPartitionLists(TargetEntry *tle, Query *query)
4393 : : {
4394 : : ListCell *lc;
4395 : :
4396 [ + - + + : 601 : foreach(lc, query->windowClause)
+ + ]
4397 : : {
4398 : 557 : WindowClause *wc = (WindowClause *) lfirst(lc);
4399 : :
4400 [ + + ]: 557 : if (!targetIsInSortList(tle, InvalidOid, wc->partitionClause))
4401 : 501 : return false;
4402 : : }
4403 : 44 : return true;
4404 : : }
4405 : :
4406 : : /*
4407 : : * qual_is_pushdown_safe - is a particular rinfo safe to push down?
4408 : : *
4409 : : * rinfo is a restriction clause applying to the given subquery (whose RTE
4410 : : * has index rti in the parent query).
4411 : : *
4412 : : * Conditions checked here:
4413 : : *
4414 : : * 1. rinfo's clause must not contain any SubPlans (mainly because it's
4415 : : * unclear that it will work correctly: SubLinks will already have been
4416 : : * transformed into SubPlans in the qual, but not in the subquery). Note that
4417 : : * SubLinks that transform to initplans are safe, and will be accepted here
4418 : : * because what we'll see in the qual is just a Param referencing the initplan
4419 : : * output.
4420 : : *
4421 : : * 2. If unsafeVolatile is set, rinfo's clause must not contain any volatile
4422 : : * functions.
4423 : : *
4424 : : * 3. If unsafeLeaky is set, rinfo's clause must not contain any leaky
4425 : : * functions that are passed Var nodes, and therefore might reveal values from
4426 : : * the subquery as side effects.
4427 : : *
4428 : : * 4. rinfo's clause must not refer to the whole-row output of the subquery
4429 : : * (since there is no easy way to name that within the subquery itself).
4430 : : *
4431 : : * 5. rinfo's clause must not refer to any subquery output columns that were
4432 : : * found to be unsafe to reference by subquery_is_pushdown_safe().
4433 : : */
4434 : : static pushdown_safe_type
1812 drowley@postgresql.o 4435 : 2527 : qual_is_pushdown_safe(Query *subquery, Index rti, RestrictInfo *rinfo,
4436 : : pushdown_safety_info *safetyInfo)
4437 : : {
1094 4438 : 2527 : pushdown_safe_type safe = PUSHDOWN_SAFE;
1812 4439 : 2527 : Node *qual = (Node *) rinfo->clause;
4440 : : List *vars;
4441 : : ListCell *vl;
4442 : :
4443 : : /* Refuse subselects (point 1) */
8394 tgl@sss.pgh.pa.us 4444 [ + + ]: 2527 : if (contain_subplans(qual))
1094 drowley@postgresql.o 4445 : 33 : return PUSHDOWN_UNSAFE;
4446 : :
4447 : : /* Refuse volatile quals if we found they'd be unsafe (point 2) */
4279 tgl@sss.pgh.pa.us 4448 [ + + + + ]: 3013 : if (safetyInfo->unsafeVolatile &&
1812 drowley@postgresql.o 4449 : 519 : contain_volatile_functions((Node *) rinfo))
1094 4450 : 9 : return PUSHDOWN_UNSAFE;
4451 : :
4452 : : /* Refuse leaky quals if told to (point 3) */
4279 tgl@sss.pgh.pa.us 4453 [ + + + + ]: 3996 : if (safetyInfo->unsafeLeaky &&
3975 sfrost@snowman.net 4454 : 1511 : contain_leaked_vars(qual))
1094 drowley@postgresql.o 4455 : 81 : return PUSHDOWN_UNSAFE;
4456 : :
4457 : : /*
4458 : : * Examine all Vars used in clause. Since it's a restriction clause, all
4459 : : * such Vars must refer to subselect output columns ... unless this is
4460 : : * part of a LATERAL subquery, in which case there could be lateral
4461 : : * references.
4462 : : *
4463 : : * By omitting the relevant flags, this also gives us a cheap sanity check
4464 : : * that no aggregates or window functions appear in the qual. Those would
4465 : : * be unsafe to push down, but at least for the moment we could never see
4466 : : * any in a qual anyhow.
4467 : : */
3657 tgl@sss.pgh.pa.us 4468 : 2404 : vars = pull_var_clause(qual, PVC_INCLUDE_PLACEHOLDERS);
8394 4469 [ + + + + : 4559 : foreach(vl, vars)
+ + ]
4470 : : {
8259 bruce@momjian.us 4471 : 2458 : Var *var = (Var *) lfirst(vl);
4472 : :
4473 : : /*
4474 : : * XXX Punt if we find any PlaceHolderVars in the restriction clause.
4475 : : * It's not clear whether a PHV could safely be pushed down, and even
4476 : : * less clear whether such a situation could arise in any cases of
4477 : : * practical interest anyway. So for the moment, just refuse to push
4478 : : * down.
4479 : : */
6354 tgl@sss.pgh.pa.us 4480 [ - + ]: 2458 : if (!IsA(var, Var))
4481 : : {
1094 drowley@postgresql.o 4482 :UBC 0 : safe = PUSHDOWN_UNSAFE;
6354 tgl@sss.pgh.pa.us 4483 : 0 : break;
4484 : : }
4485 : :
4486 : : /*
4487 : : * Punt if we find any lateral references. It would be safe to push
4488 : : * these down, but we'd have to convert them into outer references,
4489 : : * which subquery_push_qual lacks the infrastructure to do. The case
4490 : : * arises so seldom that it doesn't seem worth working hard on.
4491 : : */
2071 tgl@sss.pgh.pa.us 4492 [ + + ]:CBC 2458 : if (var->varno != rti)
4493 : : {
1094 drowley@postgresql.o 4494 : 6 : safe = PUSHDOWN_UNSAFE;
2071 tgl@sss.pgh.pa.us 4495 : 6 : break;
4496 : : }
4497 : :
4498 : : /* Subqueries have no system columns */
4666 4499 [ - + ]: 2452 : Assert(var->varattno >= 0);
4500 : :
4501 : : /* Check point 4 */
7335 4502 [ - + ]: 2452 : if (var->varattno == 0)
4503 : : {
1094 drowley@postgresql.o 4504 :UBC 0 : safe = PUSHDOWN_UNSAFE;
7335 tgl@sss.pgh.pa.us 4505 : 0 : break;
4506 : : }
4507 : :
4508 : : /* Check point 5 */
1094 drowley@postgresql.o 4509 [ + + ]:CBC 2452 : if (safetyInfo->unsafeFlags[var->varattno] != 0)
4510 : : {
4511 [ + + ]: 462 : if (safetyInfo->unsafeFlags[var->varattno] &
4512 : : (UNSAFE_HAS_VOLATILE_FUNC | UNSAFE_HAS_SET_FUNC |
4513 : : UNSAFE_NOTIN_DISTINCTON_CLAUSE | UNSAFE_TYPE_MISMATCH))
4514 : : {
4515 : 297 : safe = PUSHDOWN_UNSAFE;
4516 : 297 : break;
4517 : : }
4518 : : else
4519 : : {
4520 : : /* UNSAFE_NOTIN_PARTITIONBY_CLAUSE is ok for run conditions */
4521 : 165 : safe = PUSHDOWN_WINDOWCLAUSE_RUNCOND;
4522 : : /* don't break, we might find another Var that's unsafe */
4523 : : }
4524 : : }
4525 : : }
4526 : :
7959 neilc@samurai.com 4527 : 2404 : list_free(vars);
4528 : :
8394 tgl@sss.pgh.pa.us 4529 : 2404 : return safe;
4530 : : }
4531 : :
4532 : : /*
4533 : : * subquery_push_qual - push down a qual that we have determined is safe
4534 : : */
4535 : : static void
7589 4536 : 2139 : subquery_push_qual(Query *subquery, RangeTblEntry *rte, Index rti, Node *qual)
4537 : : {
8599 4538 [ + + ]: 2139 : if (subquery->setOperations != NULL)
4539 : : {
4540 : : /* Recurse to push it separately to each component query */
7878 4541 : 82 : recurse_push_qual(subquery->setOperations, subquery,
4542 : : rte, rti, qual);
4543 : : }
4544 : : else
4545 : : {
4546 : : /*
4547 : : * We need to replace Vars in the qual (which must refer to outputs of
4548 : : * the subquery) with copies of the subquery's targetlist expressions.
4549 : : * Note that at this point, any uplevel Vars in the qual should have
4550 : : * been replaced with Params, so they need no work.
4551 : : *
4552 : : * This step also ensures that when we are pushing into a setop tree,
4553 : : * each component query gets its own copy of the qual.
4554 : : */
4875 4555 : 2057 : qual = ReplaceVarsFromTargetList(qual, rti, 0, rte,
4556 : : subquery->targetList,
4557 : : subquery->resultRelation,
4558 : : REPLACEVARS_REPORT_ERROR, 0,
4559 : : &subquery->hasSubLinks);
4560 : :
4561 : : /*
4562 : : * Now attach the qual to the proper place: normally WHERE, but if the
4563 : : * subquery uses grouping or aggregation, put it in HAVING (since the
4564 : : * qual really refers to the group-result rows).
4565 : : */
3956 andres@anarazel.de 4566 [ + + + - : 2057 : if (subquery->hasAggs || subquery->groupClause || subquery->groupingSets || subquery->havingQual)
+ - - + ]
7675 tgl@sss.pgh.pa.us 4567 : 196 : subquery->havingQual = make_and_qual(subquery->havingQual, qual);
4568 : : else
4569 : 1861 : subquery->jointree->quals =
4570 : 1861 : make_and_qual(subquery->jointree->quals, qual);
4571 : :
4572 : : /*
4573 : : * We need not change the subquery's hasAggs or hasSubLinks flags,
4574 : : * since we can't be pushing down any aggregates that weren't there
4575 : : * before, and we don't push down subselects at all.
4576 : : */
4577 : : }
8599 4578 : 2139 : }
4579 : :
4580 : : /*
4581 : : * Helper routine to recurse through setOperations tree
4582 : : */
4583 : : static void
4584 : 246 : recurse_push_qual(Node *setOp, Query *topquery,
4585 : : RangeTblEntry *rte, Index rti, Node *qual)
4586 : : {
4587 [ + + ]: 246 : if (IsA(setOp, RangeTblRef))
4588 : : {
4589 : 164 : RangeTblRef *rtr = (RangeTblRef *) setOp;
7979 4590 : 164 : RangeTblEntry *subrte = rt_fetch(rtr->rtindex, topquery->rtable);
4591 : 164 : Query *subquery = subrte->subquery;
4592 : :
8599 4593 [ - + ]: 164 : Assert(subquery != NULL);
7589 4594 : 164 : subquery_push_qual(subquery, rte, rti, qual);
4595 : : }
8599 4596 [ + - ]: 82 : else if (IsA(setOp, SetOperationStmt))
4597 : : {
4598 : 82 : SetOperationStmt *op = (SetOperationStmt *) setOp;
4599 : :
7589 4600 : 82 : recurse_push_qual(op->larg, topquery, rte, rti, qual);
4601 : 82 : recurse_push_qual(op->rarg, topquery, rte, rti, qual);
4602 : : }
4603 : : else
4604 : : {
8269 tgl@sss.pgh.pa.us 4605 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
4606 : : (int) nodeTag(setOp));
4607 : : }
8599 tgl@sss.pgh.pa.us 4608 :CBC 246 : }
4609 : :
4610 : : /*****************************************************************************
4611 : : * SIMPLIFYING SUBQUERY TARGETLISTS
4612 : : *****************************************************************************/
4613 : :
4614 : : /*
4615 : : * remove_unused_subquery_outputs
4616 : : * Remove subquery targetlist items we don't need
4617 : : *
4618 : : * It's possible, even likely, that the upper query does not read all the
4619 : : * output columns of the subquery. We can remove any such outputs that are
4620 : : * not needed by the subquery itself (e.g., as sort/group columns) and do not
4621 : : * affect semantics otherwise (e.g., volatile functions can't be removed).
4622 : : * This is useful not only because we might be able to remove expensive-to-
4623 : : * compute expressions, but because deletion of output columns might allow
4624 : : * optimizations such as join removal to occur within the subquery.
4625 : : *
4626 : : * extra_used_attrs can be passed as non-NULL to mark any columns (offset by
4627 : : * FirstLowInvalidHeapAttributeNumber) that we should not remove. This
4628 : : * parameter is modified by the function, so callers must make a copy if they
4629 : : * need to use the passed in Bitmapset after calling this function.
4630 : : *
4631 : : * To avoid affecting column numbering in the targetlist, we don't physically
4632 : : * remove unused tlist entries, but rather replace their expressions with NULL
4633 : : * constants. This is implemented by modifying subquery->targetList.
4634 : : */
4635 : : static void
1388 drowley@postgresql.o 4636 : 13450 : remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel,
4637 : : Bitmapset *extra_used_attrs)
4638 : : {
4639 : : Bitmapset *attrs_used;
4640 : : ListCell *lc;
4641 : :
4642 : : /*
4643 : : * Just point directly to extra_used_attrs. No need to bms_copy as none of
4644 : : * the current callers use the Bitmapset after calling this function.
4645 : : */
4646 : 13450 : attrs_used = extra_used_attrs;
4647 : :
4648 : : /*
4649 : : * Do nothing if subquery has UNION/INTERSECT/EXCEPT: in principle we
4650 : : * could update all the child SELECTs' tlists, but it seems not worth the
4651 : : * trouble presently.
4652 : : */
4294 tgl@sss.pgh.pa.us 4653 [ + + ]: 13450 : if (subquery->setOperations)
4654 : 1080 : return;
4655 : :
4656 : : /*
4657 : : * If subquery has regular DISTINCT (not DISTINCT ON), we're wasting our
4658 : : * time: all its output columns must be used in the distinctClause.
4659 : : */
4660 [ + + + + ]: 12974 : if (subquery->distinctClause && !subquery->hasDistinctOn)
4661 : 447 : return;
4662 : :
4663 : : /*
4664 : : * Collect a bitmap of all the output column numbers used by the upper
4665 : : * query.
4666 : : *
4667 : : * Add all the attributes needed for joins or final output. Note: we must
4668 : : * look at rel's targetlist, not the attr_needed data, because attr_needed
4669 : : * isn't computed for inheritance child rels, cf set_append_rel_size().
4670 : : * (XXX might be worth changing that sometime.)
4671 : : */
3653 4672 : 12527 : pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
4673 : :
4674 : : /* Add all the attributes used by un-pushed-down restriction clauses. */
4294 4675 [ + + + + : 13094 : foreach(lc, rel->baserestrictinfo)
+ + ]
4676 : : {
4677 : 567 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
4678 : :
4679 : 567 : pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
4680 : : }
4681 : :
4682 : : /*
4683 : : * If there's a whole-row reference to the subquery, we can't remove
4684 : : * anything.
4685 : : */
4686 [ + + ]: 12527 : if (bms_is_member(0 - FirstLowInvalidHeapAttributeNumber, attrs_used))
4687 : 157 : return;
4688 : :
4689 : : /*
4690 : : * Run through the tlist and zap entries we don't need. It's okay to
4691 : : * modify the tlist items in-place because set_subquery_pathlist made a
4692 : : * copy of the subquery.
4693 : : */
4694 [ + + + + : 71284 : foreach(lc, subquery->targetList)
+ + ]
4695 : : {
4696 : 58914 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
4697 : 58914 : Node *texpr = (Node *) tle->expr;
4698 : :
4699 : : /*
4700 : : * If it has a sortgroupref number, it's used in some sort/group
4701 : : * clause so we'd better not remove it. Also, don't remove any
4702 : : * resjunk columns, since their reason for being has nothing to do
4703 : : * with anybody reading the subquery's output. (It's likely that
4704 : : * resjunk columns in a sub-SELECT would always have ressortgroupref
4705 : : * set, but even if they don't, it seems imprudent to remove them.)
4706 : : */
4707 [ + + - + ]: 58914 : if (tle->ressortgroupref || tle->resjunk)
4708 : 1502 : continue;
4709 : :
4710 : : /*
4711 : : * If it's used by the upper query, we can't remove it.
4712 : : */
4713 [ + + ]: 57412 : if (bms_is_member(tle->resno - FirstLowInvalidHeapAttributeNumber,
4714 : : attrs_used))
4715 : 32860 : continue;
4716 : :
4717 : : /*
4718 : : * If it contains a set-returning function, we can't remove it since
4719 : : * that could change the number of rows returned by the subquery.
4720 : : */
3470 4721 [ + + + + ]: 25098 : if (subquery->hasTargetSRFs &&
4722 : 546 : expression_returns_set(texpr))
4294 4723 : 412 : continue;
4724 : :
4725 : : /*
4726 : : * If it contains volatile functions, we daren't remove it for fear
4727 : : * that the user is expecting their side-effects to happen.
4728 : : */
4729 [ + + ]: 24140 : if (contain_volatile_functions(texpr))
4730 : 16 : continue;
4731 : :
4732 : : /*
4733 : : * OK, we don't need it. Replace the expression with a NULL constant.
4734 : : * Preserve the exposed type of the expression, in case something
4735 : : * looks at the rowtype of the subquery's result.
4736 : : */
4737 : 24124 : tle->expr = (Expr *) makeNullConst(exprType(texpr),
4738 : : exprTypmod(texpr),
4739 : : exprCollation(texpr));
4740 : : }
4741 : : }
4742 : :
4743 : : /*
4744 : : * create_partial_bitmap_paths
4745 : : * Build partial bitmap heap path for the relation
4746 : : */
4747 : : void
3294 rhaas@postgresql.org 4748 : 82563 : create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel,
4749 : : Path *bitmapqual)
4750 : : {
4751 : : int parallel_workers;
4752 : : double pages_fetched;
4753 : :
4754 : : /* Compute heap pages for bitmap heap scan */
4755 : 82563 : pages_fetched = compute_bitmap_pages(root, rel, bitmapqual, 1.0,
4756 : : NULL, NULL);
4757 : :
2963 4758 : 82563 : parallel_workers = compute_parallel_worker(rel, pages_fetched, -1,
4759 : : max_parallel_workers_per_gather);
4760 : :
3294 4761 [ + + ]: 82563 : if (parallel_workers <= 0)
4762 : 80090 : return;
4763 : :
4764 : 2473 : add_partial_path(rel, (Path *) create_bitmap_heap_path(root, rel,
4765 : : bitmapqual, rel->lateral_relids, 1.0, parallel_workers));
4766 : : }
4767 : :
4768 : : /*
4769 : : * Compute the number of parallel workers that should be used to scan a
4770 : : * relation. We compute the parallel workers based on the size of the heap to
4771 : : * be scanned and the size of the index to be scanned, then choose a minimum
4772 : : * of those.
4773 : : *
4774 : : * "heap_pages" is the number of pages from the table that we expect to scan, or
4775 : : * -1 if we don't expect to scan any.
4776 : : *
4777 : : * "index_pages" is the number of pages from the index that we expect to scan, or
4778 : : * -1 if we don't expect to scan any.
4779 : : *
4780 : : * "max_workers" is caller's limit on the number of workers. This typically
4781 : : * comes from a GUC.
4782 : : */
4783 : : int
2963 4784 : 438931 : compute_parallel_worker(RelOptInfo *rel, double heap_pages, double index_pages,
4785 : : int max_workers)
4786 : : {
3315 4787 : 438931 : int parallel_workers = 0;
4788 : :
4789 : : /*
4790 : : * If the user has set the parallel_workers reloption, use that; otherwise
4791 : : * select a default number of workers.
4792 : : */
3343 4793 [ + + ]: 438931 : if (rel->rel_parallel_workers != -1)
4794 : 1650 : parallel_workers = rel->rel_parallel_workers;
4795 : : else
4796 : : {
4797 : : /*
4798 : : * If the number of pages being scanned is insufficient to justify a
4799 : : * parallel scan, just return zero ... unless it's an inheritance
4800 : : * child. In that case, we want to generate a parallel path here
4801 : : * anyway. It might not be worthwhile just for this relation, but
4802 : : * when combined with all of its inheritance siblings it may well pay
4803 : : * off.
4804 : : */
3288 4805 [ + + + + ]: 437281 : if (rel->reloptkind == RELOPT_BASEREL &&
4806 [ + + + + ]: 416931 : ((heap_pages >= 0 && heap_pages < min_parallel_table_scan_size) ||
3189 tgl@sss.pgh.pa.us 4807 [ + + ]: 13537 : (index_pages >= 0 && index_pages < min_parallel_index_scan_size)))
3343 rhaas@postgresql.org 4808 : 416442 : return 0;
4809 : :
3288 4810 [ + + ]: 20839 : if (heap_pages >= 0)
4811 : : {
4812 : : int heap_parallel_threshold;
4813 : 19773 : int heap_parallel_workers = 1;
4814 : :
4815 : : /*
4816 : : * Select the number of workers based on the log of the size of
4817 : : * the relation. This probably needs to be a good deal more
4818 : : * sophisticated, but we need something here for now. Note that
4819 : : * the upper limit of the min_parallel_table_scan_size GUC is
4820 : : * chosen to prevent overflow here.
4821 : : */
3315 4822 : 19773 : heap_parallel_threshold = Max(min_parallel_table_scan_size, 1);
4823 [ + + ]: 22523 : while (heap_pages >= (BlockNumber) (heap_parallel_threshold * 3))
4824 : : {
4825 : 2750 : heap_parallel_workers++;
4826 : 2750 : heap_parallel_threshold *= 3;
4827 [ - + ]: 2750 : if (heap_parallel_threshold > INT_MAX / 3)
3315 rhaas@postgresql.org 4828 :UBC 0 : break; /* avoid overflow */
4829 : : }
4830 : :
3315 rhaas@postgresql.org 4831 :CBC 19773 : parallel_workers = heap_parallel_workers;
4832 : : }
4833 : :
3288 4834 [ + + ]: 20839 : if (index_pages >= 0)
4835 : : {
4836 : 4979 : int index_parallel_workers = 1;
4837 : : int index_parallel_threshold;
4838 : :
4839 : : /* same calculation as for heap_pages above */
3315 4840 : 4979 : index_parallel_threshold = Max(min_parallel_index_scan_size, 1);
4841 [ + + ]: 5117 : while (index_pages >= (BlockNumber) (index_parallel_threshold * 3))
4842 : : {
4843 : 138 : index_parallel_workers++;
4844 : 138 : index_parallel_threshold *= 3;
4845 [ - + ]: 138 : if (index_parallel_threshold > INT_MAX / 3)
3315 rhaas@postgresql.org 4846 :UBC 0 : break; /* avoid overflow */
4847 : : }
4848 : :
3315 rhaas@postgresql.org 4849 [ + + ]:CBC 4979 : if (parallel_workers > 0)
4850 : 3913 : parallel_workers = Min(parallel_workers, index_parallel_workers);
4851 : : else
4852 : 1066 : parallel_workers = index_parallel_workers;
4853 : : }
4854 : : }
4855 : :
4856 : : /* In no case use more than caller supplied maximum number of workers */
2963 4857 : 22489 : parallel_workers = Min(parallel_workers, max_workers);
4858 : :
3343 4859 : 22489 : return parallel_workers;
4860 : : }
4861 : :
4862 : : /*
4863 : : * generate_partitionwise_join_paths
4864 : : * Create paths representing partitionwise join for given partitioned
4865 : : * join relation.
4866 : : *
4867 : : * This must not be called until after we are done adding paths for all
4868 : : * child-joins. Otherwise, add_path might delete a path to which some path
4869 : : * generated here has a reference.
4870 : : */
4871 : : void
2949 peter_e@gmx.net 4872 : 139093 : generate_partitionwise_join_paths(PlannerInfo *root, RelOptInfo *rel)
4873 : : {
3082 rhaas@postgresql.org 4874 : 139093 : List *live_children = NIL;
4875 : : int cnt_parts;
4876 : : int num_parts;
4877 : : RelOptInfo **part_rels;
4878 : :
4879 : : /* Handle only join relations here. */
4880 [ + + - + ]: 139093 : if (!IS_JOIN_REL(rel))
3082 rhaas@postgresql.org 4881 :UBC 0 : return;
4882 : :
4883 : : /* We've nothing to do if the relation is not partitioned. */
2960 rhaas@postgresql.org 4884 [ + + + + :CBC 139093 : if (!IS_PARTITIONED_REL(rel))
+ + + - +
+ ]
3082 4885 : 135496 : return;
4886 : :
4887 : : /* The relation should have consider_partitionwise_join set. */
2753 efujita@postgresql.o 4888 [ - + ]: 3597 : Assert(rel->consider_partitionwise_join);
4889 : :
4890 : : /* Guard against stack overflow due to overly deep partition hierarchy. */
3082 rhaas@postgresql.org 4891 : 3597 : check_stack_depth();
4892 : :
4893 : 3597 : num_parts = rel->nparts;
4894 : 3597 : part_rels = rel->part_rels;
4895 : :
4896 : : /* Collect non-dummy child-joins. */
4897 [ + + ]: 12820 : for (cnt_parts = 0; cnt_parts < num_parts; cnt_parts++)
4898 : : {
4899 : 9223 : RelOptInfo *child_rel = part_rels[cnt_parts];
4900 : :
4901 : : /* If it's been pruned entirely, it's certainly dummy. */
2542 tgl@sss.pgh.pa.us 4902 [ + + ]: 9223 : if (child_rel == NULL)
4903 : 32 : continue;
4904 : :
4905 : : /* Make partitionwise join paths for this partitioned child-join. */
2949 peter_e@gmx.net 4906 : 9191 : generate_partitionwise_join_paths(root, child_rel);
4907 : :
4908 : : /* If we failed to make any path for this child, we must give up. */
1197 tgl@sss.pgh.pa.us 4909 [ - + ]: 9191 : if (child_rel->pathlist == NIL)
4910 : : {
4911 : : /*
4912 : : * Mark the parent joinrel as unpartitioned so that later
4913 : : * functions treat it correctly.
4914 : : */
1197 tgl@sss.pgh.pa.us 4915 :UBC 0 : rel->nparts = 0;
4916 : 0 : return;
4917 : : }
4918 : :
4919 : : /* Else, identify the cheapest path for it. */
2565 tgl@sss.pgh.pa.us 4920 :CBC 9191 : set_cheapest(child_rel);
4921 : :
4922 : : /* Dummy children need not be scanned, so ignore those. */
3082 rhaas@postgresql.org 4923 [ - + ]: 9191 : if (IS_DUMMY_REL(child_rel))
3082 rhaas@postgresql.org 4924 :UBC 0 : continue;
4925 : :
4926 : : /*
4927 : : * Except for the topmost scan/join rel, consider generating partial
4928 : : * aggregation paths for the grouped relation on top of the paths of
4929 : : * this partitioned child-join. After that, we're done creating paths
4930 : : * for the grouped relation, so run set_cheapest().
4931 : : */
158 rguo@postgresql.org 4932 [ + + ]:GNC 9191 : if (child_rel->grouped_rel != NULL &&
4933 [ + + - + : 6438 : !bms_equal(IS_OTHER_REL(rel) ?
+ + ]
4934 : : rel->top_parent_relids : rel->relids,
4935 [ + - ]: 6438 : root->all_query_rels))
4936 : : {
4937 : 120 : RelOptInfo *grouped_rel = child_rel->grouped_rel;
4938 : :
4939 [ - + ]: 120 : Assert(IS_GROUPED_REL(grouped_rel));
4940 : :
4941 : 120 : generate_grouped_paths(root, grouped_rel, child_rel);
4942 : 120 : set_cheapest(grouped_rel);
4943 : : }
4944 : :
4945 : : #ifdef OPTIMIZER_DEBUG
4946 : : pprint(child_rel);
4947 : : #endif
4948 : :
3082 rhaas@postgresql.org 4949 :CBC 9191 : live_children = lappend(live_children, child_rel);
4950 : : }
4951 : :
4952 : : /* If all child-joins are dummy, parent join is also dummy. */
4953 [ - + ]: 3597 : if (!live_children)
4954 : : {
3082 rhaas@postgresql.org 4955 :UBC 0 : mark_dummy_rel(rel);
4956 : 0 : return;
4957 : : }
4958 : :
4959 : : /* Build additional paths for this rel from child-join paths. */
3082 rhaas@postgresql.org 4960 :CBC 3597 : add_paths_to_append_rel(root, rel, live_children);
4961 : 3597 : list_free(live_children);
4962 : : }
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