Branch data Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * equivclass.c
4 : : * Routines for managing EquivalenceClasses
5 : : *
6 : : * See src/backend/optimizer/README for discussion of EquivalenceClasses.
7 : : *
8 : : *
9 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
10 : : * Portions Copyright (c) 1994, Regents of the University of California
11 : : *
12 : : * IDENTIFICATION
13 : : * src/backend/optimizer/path/equivclass.c
14 : : *
15 : : *-------------------------------------------------------------------------
16 : : */
17 : : #include "postgres.h"
18 : :
19 : : #include <limits.h>
20 : :
21 : : #include "access/stratnum.h"
22 : : #include "catalog/pg_type.h"
23 : : #include "common/hashfn.h"
24 : : #include "nodes/makefuncs.h"
25 : : #include "nodes/nodeFuncs.h"
26 : : #include "optimizer/appendinfo.h"
27 : : #include "optimizer/clauses.h"
28 : : #include "optimizer/optimizer.h"
29 : : #include "optimizer/pathnode.h"
30 : : #include "optimizer/paths.h"
31 : : #include "optimizer/planmain.h"
32 : : #include "optimizer/restrictinfo.h"
33 : : #include "rewrite/rewriteManip.h"
34 : : #include "utils/lsyscache.h"
35 : :
36 : :
37 : : static EquivalenceMember *make_eq_member(EquivalenceClass *ec,
38 : : Expr *expr, Relids relids,
39 : : JoinDomain *jdomain,
40 : : EquivalenceMember *parent,
41 : : Oid datatype);
42 : : static EquivalenceMember *add_eq_member(EquivalenceClass *ec,
43 : : Expr *expr, Relids relids,
44 : : JoinDomain *jdomain,
45 : : Oid datatype);
46 : : static EquivalenceMember *add_child_eq_member(PlannerInfo *root,
47 : : EquivalenceClass *ec,
48 : : int ec_index, Expr *expr,
49 : : Relids relids,
50 : : JoinDomain *jdomain,
51 : : EquivalenceMember *parent_em,
52 : : Oid datatype,
53 : : Index child_relid);
54 : : static void generate_base_implied_equalities_const(PlannerInfo *root,
55 : : EquivalenceClass *ec);
56 : : static void generate_base_implied_equalities_no_const(PlannerInfo *root,
57 : : EquivalenceClass *ec);
58 : : static void generate_base_implied_equalities_broken(PlannerInfo *root,
59 : : EquivalenceClass *ec);
60 : : static List *generate_join_implied_equalities_normal(PlannerInfo *root,
61 : : EquivalenceClass *ec,
62 : : Relids join_relids,
63 : : Relids outer_relids,
64 : : Relids inner_relids);
65 : : static List *generate_join_implied_equalities_broken(PlannerInfo *root,
66 : : EquivalenceClass *ec,
67 : : Relids nominal_join_relids,
68 : : Relids outer_relids,
69 : : Relids nominal_inner_relids,
70 : : RelOptInfo *inner_rel);
71 : : static Oid select_equality_operator(EquivalenceClass *ec,
72 : : Oid lefttype, Oid righttype);
73 : : static RestrictInfo *create_join_clause(PlannerInfo *root,
74 : : EquivalenceClass *ec, Oid opno,
75 : : EquivalenceMember *leftem,
76 : : EquivalenceMember *rightem,
77 : : EquivalenceClass *parent_ec);
78 : : static bool reconsider_outer_join_clause(PlannerInfo *root,
79 : : OuterJoinClauseInfo *ojcinfo,
80 : : bool outer_on_left);
81 : : static bool reconsider_full_join_clause(PlannerInfo *root,
82 : : OuterJoinClauseInfo *ojcinfo);
83 : : static JoinDomain *find_join_domain(PlannerInfo *root, Relids relids);
84 : : static Bitmapset *get_eclass_indexes_for_relids(PlannerInfo *root,
85 : : Relids relids);
86 : : static Bitmapset *get_common_eclass_indexes(PlannerInfo *root, Relids relids1,
87 : : Relids relids2);
88 : : static void ec_build_derives_hash(PlannerInfo *root, EquivalenceClass *ec);
89 : : static void ec_add_derived_clauses(EquivalenceClass *ec, List *clauses);
90 : : static void ec_add_derived_clause(EquivalenceClass *ec, RestrictInfo *clause);
91 : : static void ec_add_clause_to_derives_hash(EquivalenceClass *ec, RestrictInfo *rinfo);
92 : : static RestrictInfo *ec_search_clause_for_ems(PlannerInfo *root, EquivalenceClass *ec,
93 : : EquivalenceMember *leftem,
94 : : EquivalenceMember *rightem,
95 : : EquivalenceClass *parent_ec);
96 : : static RestrictInfo *ec_search_derived_clause_for_ems(PlannerInfo *root,
97 : : EquivalenceClass *ec,
98 : : EquivalenceMember *leftem,
99 : : EquivalenceMember *rightem,
100 : : EquivalenceClass *parent_ec);
101 : :
102 : : /*
103 : : * Hash key identifying a derived clause.
104 : : *
105 : : * This structure should not be filled manually. Use fill_ec_derives_key() to
106 : : * set it up in canonical form.
107 : : */
108 : : typedef struct
109 : : {
110 : : EquivalenceMember *em1;
111 : : EquivalenceMember *em2;
112 : : EquivalenceClass *parent_ec;
113 : : } ECDerivesKey;
114 : :
115 : : /* Hash table entry in ec_derives_hash. */
116 : : typedef struct
117 : : {
118 : : uint32 status;
119 : : ECDerivesKey key;
120 : : RestrictInfo *rinfo;
121 : : } ECDerivesEntry;
122 : :
123 : : /* Threshold for switching from list to hash table */
124 : : #define EC_DERIVES_HASH_THRESHOLD 32
125 : :
126 : : #define SH_PREFIX derives
127 : : #define SH_ELEMENT_TYPE ECDerivesEntry
128 : : #define SH_KEY_TYPE ECDerivesKey
129 : : #define SH_KEY key
130 : : #define SH_HASH_KEY(tb, key) \
131 : : hash_bytes((const unsigned char *) &(key), sizeof(ECDerivesKey))
132 : : #define SH_EQUAL(tb, a, b) \
133 : : ((a).em1 == (b).em1 && (a).em2 == (b).em2 && (a).parent_ec == (b).parent_ec)
134 : : #define SH_SCOPE static inline
135 : : #define SH_DECLARE
136 : : #define SH_DEFINE
137 : : #include "lib/simplehash.h"
138 : :
139 : : /*
140 : : * process_equivalence
141 : : * The given clause has a mergejoinable operator and is not an outer-join
142 : : * qualification, so its two sides can be considered equal
143 : : * anywhere they are both computable; moreover that equality can be
144 : : * extended transitively. Record this knowledge in the EquivalenceClass
145 : : * data structure, if applicable. Returns true if successful, false if not
146 : : * (in which case caller should treat the clause as ordinary, not an
147 : : * equivalence).
148 : : *
149 : : * In some cases, although we cannot convert a clause into EquivalenceClass
150 : : * knowledge, we can still modify it to a more useful form than the original.
151 : : * Then, *p_restrictinfo will be replaced by a new RestrictInfo, which is what
152 : : * the caller should use for further processing.
153 : : *
154 : : * jdomain is the join domain within which the given clause was found.
155 : : * This limits the applicability of deductions from the EquivalenceClass,
156 : : * as described in optimizer/README.
157 : : *
158 : : * We reject proposed equivalence clauses if they contain leaky functions
159 : : * and have security_level above zero. The EC evaluation rules require us to
160 : : * apply certain tests at certain joining levels, and we can't tolerate
161 : : * delaying any test on security_level grounds. By rejecting candidate clauses
162 : : * that might require security delays, we ensure it's safe to apply an EC
163 : : * clause as soon as it's supposed to be applied.
164 : : *
165 : : * On success return, we have also initialized the clause's left_ec/right_ec
166 : : * fields to point to the EquivalenceClass representing it. This saves lookup
167 : : * effort later.
168 : : *
169 : : * Note: constructing merged EquivalenceClasses is a standard UNION-FIND
170 : : * problem, for which there exist better data structures than simple lists.
171 : : * If this code ever proves to be a bottleneck then it could be sped up ---
172 : : * but for now, simple is beautiful.
173 : : *
174 : : * Note: this is only called during planner startup, not during GEQO
175 : : * exploration, so we need not worry about whether we're in the right
176 : : * memory context.
177 : : */
178 : : bool
179 : 28038 : process_equivalence(PlannerInfo *root,
180 : : RestrictInfo **p_restrictinfo,
181 : : JoinDomain *jdomain)
182 : : {
183 : 28038 : RestrictInfo *restrictinfo = *p_restrictinfo;
184 : 28038 : Expr *clause = restrictinfo->clause;
185 : 28038 : Oid opno,
186 : : collation,
187 : : item1_type,
188 : : item2_type;
189 : 28038 : Expr *item1;
190 : 28038 : Expr *item2;
191 : 28038 : Relids item1_relids,
192 : : item2_relids;
193 : 28038 : List *opfamilies;
194 : 28038 : EquivalenceClass *ec1,
195 : : *ec2;
196 : 28038 : EquivalenceMember *em1,
197 : : *em2;
198 : 28038 : ListCell *lc1;
199 : 28038 : int ec2_idx;
200 : :
201 : : /* Should not already be marked as having generated an eclass */
202 [ + - ]: 28038 : Assert(restrictinfo->left_ec == NULL);
203 [ + - ]: 28038 : Assert(restrictinfo->right_ec == NULL);
204 : :
205 : : /* Reject if it is potentially postponable by security considerations */
206 [ + + + + ]: 28038 : if (restrictinfo->security_level > 0 && !restrictinfo->leakproof)
207 : 34 : return false;
208 : :
209 : : /* Extract info from given clause */
210 [ + - ]: 28004 : Assert(is_opclause(clause));
211 : 28004 : opno = ((OpExpr *) clause)->opno;
212 : 28004 : collation = ((OpExpr *) clause)->inputcollid;
213 : 28004 : item1 = (Expr *) get_leftop(clause);
214 : 28004 : item2 = (Expr *) get_rightop(clause);
215 : 28004 : item1_relids = restrictinfo->left_relids;
216 : 28004 : item2_relids = restrictinfo->right_relids;
217 : :
218 : : /*
219 : : * Ensure both input expressions expose the desired collation (their types
220 : : * should be OK already); see comments for canonicalize_ec_expression.
221 : : */
222 : 56008 : item1 = canonicalize_ec_expression(item1,
223 : 28004 : exprType((Node *) item1),
224 : 28004 : collation);
225 : 56008 : item2 = canonicalize_ec_expression(item2,
226 : 28004 : exprType((Node *) item2),
227 : 28004 : collation);
228 : :
229 : : /*
230 : : * Clauses of the form X=X cannot be translated into EquivalenceClasses.
231 : : * We'd either end up with a single-entry EC, losing the knowledge that
232 : : * the clause was present at all, or else make an EC with duplicate
233 : : * entries, causing other issues.
234 : : */
235 [ + + ]: 28004 : if (equal(item1, item2))
236 : : {
237 : : /*
238 : : * If the operator is strict, then the clause can be treated as just
239 : : * "X IS NOT NULL". (Since we know we are considering a top-level
240 : : * qual, we can ignore the difference between FALSE and NULL results.)
241 : : * It's worth making the conversion because we'll typically get a much
242 : : * better selectivity estimate than we would for X=X.
243 : : *
244 : : * If the operator is not strict, we can't be sure what it will do
245 : : * with NULLs, so don't attempt to optimize it.
246 : : */
247 : 9 : set_opfuncid((OpExpr *) clause);
248 [ - + ]: 9 : if (func_strict(((OpExpr *) clause)->opfuncid))
249 : : {
250 : 9 : NullTest *ntest = makeNode(NullTest);
251 : :
252 : 9 : ntest->arg = item1;
253 : 9 : ntest->nulltesttype = IS_NOT_NULL;
254 : 9 : ntest->argisrow = false; /* correct even if composite arg */
255 : 9 : ntest->location = -1;
256 : :
257 : 9 : *p_restrictinfo =
258 : 18 : make_restrictinfo(root,
259 : 9 : (Expr *) ntest,
260 : 9 : restrictinfo->is_pushed_down,
261 : 9 : restrictinfo->has_clone,
262 : 9 : restrictinfo->is_clone,
263 : 9 : restrictinfo->pseudoconstant,
264 : 9 : restrictinfo->security_level,
265 : : NULL,
266 : 9 : restrictinfo->incompatible_relids,
267 : 9 : restrictinfo->outer_relids);
268 : 9 : }
269 : 9 : return false;
270 : : }
271 : :
272 : : /*
273 : : * We use the declared input types of the operator, not exprType() of the
274 : : * inputs, as the nominal datatypes for opfamily lookup. This presumes
275 : : * that btree operators are always registered with amoplefttype and
276 : : * amoprighttype equal to their declared input types. We will need this
277 : : * info anyway to build EquivalenceMember nodes, and by extracting it now
278 : : * we can use type comparisons to short-circuit some equal() tests.
279 : : */
280 : 27995 : op_input_types(opno, &item1_type, &item2_type);
281 : :
282 : 27995 : opfamilies = restrictinfo->mergeopfamilies;
283 : :
284 : : /*
285 : : * Sweep through the existing EquivalenceClasses looking for matches to
286 : : * item1 and item2. These are the possible outcomes:
287 : : *
288 : : * 1. We find both in the same EC. The equivalence is already known, so
289 : : * there's nothing to do.
290 : : *
291 : : * 2. We find both in different ECs. Merge the two ECs together.
292 : : *
293 : : * 3. We find just one. Add the other to its EC.
294 : : *
295 : : * 4. We find neither. Make a new, two-entry EC.
296 : : *
297 : : * Note: since all ECs are built through this process or the similar
298 : : * search in get_eclass_for_sort_expr(), it's impossible that we'd match
299 : : * an item in more than one existing nonvolatile EC. So it's okay to stop
300 : : * at the first match.
301 : : */
302 : 27995 : ec1 = ec2 = NULL;
303 : 27995 : em1 = em2 = NULL;
304 : 27995 : ec2_idx = -1;
305 [ + + + + : 46274 : foreach(lc1, root->eq_classes)
+ + ]
306 : : {
307 : 18279 : EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
308 : 18279 : ListCell *lc2;
309 : :
310 : : /* Never match to a volatile EC */
311 [ - + ]: 18279 : if (cur_ec->ec_has_volatile)
312 : 0 : continue;
313 : :
314 : : /*
315 : : * The collation has to match; check this first since it's cheaper
316 : : * than the opfamily comparison.
317 : : */
318 [ + + ]: 18279 : if (collation != cur_ec->ec_collation)
319 : 1289 : continue;
320 : :
321 : : /*
322 : : * A "match" requires matching sets of btree opfamilies. Use of
323 : : * equal() for this test has implications discussed in the comments
324 : : * for get_mergejoin_opfamilies().
325 : : */
326 [ + + ]: 16990 : if (!equal(opfamilies, cur_ec->ec_opfamilies))
327 : 5545 : continue;
328 : :
329 : : /* We don't expect any children yet */
330 [ + - ]: 11445 : Assert(cur_ec->ec_childmembers == NULL);
331 : :
332 [ + - + + : 34682 : foreach(lc2, cur_ec->ec_members)
+ + ]
333 : : {
334 : 23237 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
335 : :
336 : : /* Child members should not exist in ec_members */
337 [ - + ]: 23237 : Assert(!cur_em->em_is_child);
338 : :
339 : : /*
340 : : * Match constants only within the same JoinDomain (see
341 : : * optimizer/README).
342 : : */
343 [ + + + + ]: 23237 : if (cur_em->em_is_const && cur_em->em_jdomain != jdomain)
344 : 282 : continue;
345 : :
346 [ + + ]: 22955 : if (!ec1 &&
347 [ + + + + ]: 22298 : item1_type == cur_em->em_datatype &&
348 : 22248 : equal(item1, cur_em->em_expr))
349 : : {
350 : 1508 : ec1 = cur_ec;
351 : 1508 : em1 = cur_em;
352 [ + + ]: 1508 : if (ec2)
353 : 5 : break;
354 : 1503 : }
355 : :
356 [ + + ]: 22950 : if (!ec2 &&
357 [ + + + + ]: 22690 : item2_type == cur_em->em_datatype &&
358 : 22627 : equal(item2, cur_em->em_expr))
359 : : {
360 : 335 : ec2 = cur_ec;
361 : 335 : ec2_idx = foreach_current_index(lc1);
362 : 335 : em2 = cur_em;
363 [ + + ]: 335 : if (ec1)
364 : 3 : break;
365 : 332 : }
366 [ + + + ]: 23237 : }
367 : :
368 [ + + + + ]: 11445 : if (ec1 && ec2)
369 : 8 : break;
370 [ + + + ]: 18279 : }
371 : :
372 : : /* Sweep finished, what did we find? */
373 : :
374 [ + + + + ]: 27995 : if (ec1 && ec2)
375 : : {
376 : : /* If case 1, nothing to do, except add to sources */
377 [ + + ]: 8 : if (ec1 == ec2)
378 : : {
379 : 2 : ec1->ec_sources = lappend(ec1->ec_sources, restrictinfo);
380 [ - + ]: 2 : ec1->ec_min_security = Min(ec1->ec_min_security,
381 : : restrictinfo->security_level);
382 [ - + ]: 2 : ec1->ec_max_security = Max(ec1->ec_max_security,
383 : : restrictinfo->security_level);
384 : : /* mark the RI as associated with this eclass */
385 : 2 : restrictinfo->left_ec = ec1;
386 : 2 : restrictinfo->right_ec = ec1;
387 : : /* mark the RI as usable with this pair of EMs */
388 : 2 : restrictinfo->left_em = em1;
389 : 2 : restrictinfo->right_em = em2;
390 : 2 : return true;
391 : : }
392 : :
393 : : /*
394 : : * Case 2: need to merge ec1 and ec2. This should never happen after
395 : : * the ECs have reached canonical state; otherwise, pathkeys could be
396 : : * rendered non-canonical by the merge, and relation eclass indexes
397 : : * would get broken by removal of an eq_classes list entry.
398 : : */
399 [ + - ]: 6 : if (root->ec_merging_done)
400 [ # # # # ]: 0 : elog(ERROR, "too late to merge equivalence classes");
401 : :
402 : : /*
403 : : * We add ec2's items to ec1, then set ec2's ec_merged link to point
404 : : * to ec1 and remove ec2 from the eq_classes list. We cannot simply
405 : : * delete ec2 because that could leave dangling pointers in existing
406 : : * PathKeys. We leave it behind with a link so that the merged EC can
407 : : * be found.
408 : : */
409 : 6 : ec1->ec_members = list_concat(ec1->ec_members, ec2->ec_members);
410 : 6 : ec1->ec_sources = list_concat(ec1->ec_sources, ec2->ec_sources);
411 : :
412 : : /*
413 : : * Appends ec2's derived clauses to ec1->ec_derives_list and adds them
414 : : * to ec1->ec_derives_hash if present.
415 : : */
416 : 6 : ec_add_derived_clauses(ec1, ec2->ec_derives_list);
417 : 6 : ec1->ec_relids = bms_join(ec1->ec_relids, ec2->ec_relids);
418 : 6 : ec1->ec_has_const |= ec2->ec_has_const;
419 : : /* can't need to set has_volatile */
420 [ - + ]: 6 : ec1->ec_min_security = Min(ec1->ec_min_security,
421 : : ec2->ec_min_security);
422 [ - + ]: 6 : ec1->ec_max_security = Max(ec1->ec_max_security,
423 : : ec2->ec_max_security);
424 : 6 : ec2->ec_merged = ec1;
425 : 6 : root->eq_classes = list_delete_nth_cell(root->eq_classes, ec2_idx);
426 : : /* just to avoid debugging confusion w/ dangling pointers: */
427 : 6 : ec2->ec_members = NIL;
428 : 6 : ec2->ec_sources = NIL;
429 : 6 : ec_clear_derived_clauses(ec2);
430 : 6 : ec2->ec_relids = NULL;
431 : 6 : ec1->ec_sources = lappend(ec1->ec_sources, restrictinfo);
432 [ - + ]: 6 : ec1->ec_min_security = Min(ec1->ec_min_security,
433 : : restrictinfo->security_level);
434 [ - + ]: 6 : ec1->ec_max_security = Max(ec1->ec_max_security,
435 : : restrictinfo->security_level);
436 : : /* mark the RI as associated with this eclass */
437 : 6 : restrictinfo->left_ec = ec1;
438 : 6 : restrictinfo->right_ec = ec1;
439 : : /* mark the RI as usable with this pair of EMs */
440 : 6 : restrictinfo->left_em = em1;
441 : 6 : restrictinfo->right_em = em2;
442 : 6 : }
443 [ + + ]: 27987 : else if (ec1)
444 : : {
445 : : /* Case 3: add item2 to ec1 */
446 : 3000 : em2 = add_eq_member(ec1, item2, item2_relids,
447 : 1500 : jdomain, item2_type);
448 : 1500 : ec1->ec_sources = lappend(ec1->ec_sources, restrictinfo);
449 [ + + ]: 1500 : ec1->ec_min_security = Min(ec1->ec_min_security,
450 : : restrictinfo->security_level);
451 [ - + ]: 1500 : ec1->ec_max_security = Max(ec1->ec_max_security,
452 : : restrictinfo->security_level);
453 : : /* mark the RI as associated with this eclass */
454 : 1500 : restrictinfo->left_ec = ec1;
455 : 1500 : restrictinfo->right_ec = ec1;
456 : : /* mark the RI as usable with this pair of EMs */
457 : 1500 : restrictinfo->left_em = em1;
458 : 1500 : restrictinfo->right_em = em2;
459 : 1500 : }
460 [ + + ]: 26487 : else if (ec2)
461 : : {
462 : : /* Case 3: add item1 to ec2 */
463 : 654 : em1 = add_eq_member(ec2, item1, item1_relids,
464 : 327 : jdomain, item1_type);
465 : 327 : ec2->ec_sources = lappend(ec2->ec_sources, restrictinfo);
466 [ - + ]: 327 : ec2->ec_min_security = Min(ec2->ec_min_security,
467 : : restrictinfo->security_level);
468 [ - + ]: 327 : ec2->ec_max_security = Max(ec2->ec_max_security,
469 : : restrictinfo->security_level);
470 : : /* mark the RI as associated with this eclass */
471 : 327 : restrictinfo->left_ec = ec2;
472 : 327 : restrictinfo->right_ec = ec2;
473 : : /* mark the RI as usable with this pair of EMs */
474 : 327 : restrictinfo->left_em = em1;
475 : 327 : restrictinfo->right_em = em2;
476 : 327 : }
477 : : else
478 : : {
479 : : /* Case 4: make a new, two-entry EC */
480 : 26160 : EquivalenceClass *ec = makeNode(EquivalenceClass);
481 : :
482 : 26160 : ec->ec_opfamilies = opfamilies;
483 : 26160 : ec->ec_collation = collation;
484 : 26160 : ec->ec_childmembers_size = 0;
485 : 26160 : ec->ec_members = NIL;
486 : 26160 : ec->ec_childmembers = NULL;
487 : 26160 : ec->ec_sources = list_make1(restrictinfo);
488 : 26160 : ec->ec_derives_list = NIL;
489 : 26160 : ec->ec_derives_hash = NULL;
490 : 26160 : ec->ec_relids = NULL;
491 : 26160 : ec->ec_has_const = false;
492 : 26160 : ec->ec_has_volatile = false;
493 : 26160 : ec->ec_broken = false;
494 : 26160 : ec->ec_sortref = 0;
495 : 26160 : ec->ec_min_security = restrictinfo->security_level;
496 : 26160 : ec->ec_max_security = restrictinfo->security_level;
497 : 26160 : ec->ec_merged = NULL;
498 : 52320 : em1 = add_eq_member(ec, item1, item1_relids,
499 : 26160 : jdomain, item1_type);
500 : 52320 : em2 = add_eq_member(ec, item2, item2_relids,
501 : 26160 : jdomain, item2_type);
502 : :
503 : 26160 : root->eq_classes = lappend(root->eq_classes, ec);
504 : :
505 : : /* mark the RI as associated with this eclass */
506 : 26160 : restrictinfo->left_ec = ec;
507 : 26160 : restrictinfo->right_ec = ec;
508 : : /* mark the RI as usable with this pair of EMs */
509 : 26160 : restrictinfo->left_em = em1;
510 : 26160 : restrictinfo->right_em = em2;
511 : 26160 : }
512 : :
513 : 27993 : return true;
514 : 28038 : }
515 : :
516 : : /*
517 : : * canonicalize_ec_expression
518 : : *
519 : : * This function ensures that the expression exposes the expected type and
520 : : * collation, so that it will be equal() to other equivalence-class expressions
521 : : * that it ought to be equal() to.
522 : : *
523 : : * The rule for datatypes is that the exposed type should match what it would
524 : : * be for an input to an operator of the EC's opfamilies; which is usually
525 : : * the declared input type of the operator, but in the case of polymorphic
526 : : * operators no relabeling is wanted (compare the behavior of parse_coerce.c).
527 : : * Expressions coming in from quals will generally have the right type
528 : : * already, but expressions coming from indexkeys may not (because they are
529 : : * represented without any explicit relabel in pg_index), and the same problem
530 : : * occurs for sort expressions (because the parser is likewise cavalier about
531 : : * putting relabels on them). Such cases will be binary-compatible with the
532 : : * real operators, so adding a RelabelType is sufficient.
533 : : *
534 : : * Also, the expression's exposed collation must match the EC's collation.
535 : : * This is important because in comparisons like "foo < bar COLLATE baz",
536 : : * only one of the expressions has the correct exposed collation as we receive
537 : : * it from the parser. Forcing both of them to have it ensures that all
538 : : * variant spellings of such a construct behave the same. Again, we can
539 : : * stick on a RelabelType to force the right exposed collation. (It might
540 : : * work to not label the collation at all in EC members, but this is risky
541 : : * since some parts of the system expect exprCollation() to deliver the
542 : : * right answer for a sort key.)
543 : : */
544 : : Expr *
545 : 593596 : canonicalize_ec_expression(Expr *expr, Oid req_type, Oid req_collation)
546 : : {
547 : 593596 : Oid expr_type = exprType((Node *) expr);
548 : :
549 : : /*
550 : : * For a polymorphic-input-type opclass, just keep the same exposed type.
551 : : * RECORD opclasses work like polymorphic-type ones for this purpose.
552 : : */
553 [ + + + + : 593596 : if (IsPolymorphicType(req_type) || req_type == RECORDOID)
+ - + + +
+ + + + -
+ - + - +
- + - ]
554 : 593596 : req_type = expr_type;
555 : :
556 : : /*
557 : : * No work if the expression exposes the right type/collation already.
558 : : */
559 [ + + + + ]: 982 : if (expr_type != req_type ||
560 : 286000 : exprCollation((Node *) expr) != req_collation)
561 : : {
562 : : /*
563 : : * If we have to change the type of the expression, set typmod to -1,
564 : : * since the new type may not have the same typmod interpretation.
565 : : * When we only have to change collation, preserve the exposed typmod.
566 : : */
567 : 558529 : int32 req_typmod;
568 : :
569 [ + + ]: 558529 : if (expr_type != req_type)
570 : 11289 : req_typmod = -1;
571 : : else
572 : 218 : req_typmod = exprTypmod((Node *) expr);
573 : :
574 : : /*
575 : : * Use applyRelabelType so that we preserve const-flatness. This is
576 : : * important since eval_const_expressions has already been applied.
577 : : */
578 : 23014 : expr = (Expr *) applyRelabelType((Node *) expr,
579 : 11507 : req_type, req_typmod, req_collation,
580 : : COERCE_IMPLICIT_CAST, -1, false);
581 : 11507 : }
582 : :
583 : 47992 : return expr;
584 : 23996 : }
585 : :
586 : : /*
587 : : * make_eq_member
588 : : * Build a new EquivalenceMember without adding it to an EC. If 'parent'
589 : : * is NULL, the result will be a parent member, otherwise a child member.
590 : : */
591 : : static EquivalenceMember *
592 : 97842 : make_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids,
593 : : JoinDomain *jdomain, EquivalenceMember *parent, Oid datatype)
594 : : {
595 : 97842 : EquivalenceMember *em = makeNode(EquivalenceMember);
596 : :
597 : 97842 : em->em_expr = expr;
598 : 97842 : em->em_relids = relids;
599 : 97842 : em->em_is_const = false;
600 : 97842 : em->em_is_child = (parent != NULL);
601 : 97842 : em->em_datatype = datatype;
602 : 97842 : em->em_jdomain = jdomain;
603 : 97842 : em->em_parent = parent;
604 : :
605 [ + + ]: 97842 : if (bms_is_empty(relids))
606 : : {
607 : : /*
608 : : * No Vars, assume it's a pseudoconstant. This is correct for entries
609 : : * generated from process_equivalence(), because a WHERE clause can't
610 : : * contain aggregates or SRFs, and non-volatility was checked before
611 : : * process_equivalence() ever got called. But
612 : : * get_eclass_for_sort_expr() has to work harder. We put the tests
613 : : * there not here to save cycles in the equivalence case.
614 : : */
615 [ + - ]: 20652 : Assert(!parent);
616 : 20652 : em->em_is_const = true;
617 : 20652 : ec->ec_has_const = true;
618 : : /* it can't affect ec_relids */
619 : 20652 : }
620 : :
621 : 195684 : return em;
622 : 97842 : }
623 : :
624 : : /*
625 : : * add_eq_member - build a new non-child EquivalenceMember and add it to 'ec'.
626 : : */
627 : : static EquivalenceMember *
628 : 83610 : add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids,
629 : : JoinDomain *jdomain, Oid datatype)
630 : : {
631 : 167220 : EquivalenceMember *em = make_eq_member(ec, expr, relids, jdomain,
632 : 83610 : NULL, datatype);
633 : :
634 : : /* add to the members list */
635 : 83610 : ec->ec_members = lappend(ec->ec_members, em);
636 : :
637 : : /* record the relids for parent members */
638 : 83610 : ec->ec_relids = bms_add_members(ec->ec_relids, relids);
639 : :
640 : 167220 : return em;
641 : 83610 : }
642 : :
643 : : /*
644 : : * add_child_eq_member
645 : : * Create an em_is_child=true EquivalenceMember and add it to 'ec'.
646 : : *
647 : : * 'root' is the PlannerInfo that 'ec' belongs to.
648 : : * 'ec' is the EquivalenceClass to add the child member to.
649 : : * 'ec_index' the index of 'ec' within root->eq_classes, or -1 if maintaining
650 : : * the RelOptInfo.eclass_indexes isn't needed.
651 : : * 'expr' is the em_expr for the new member.
652 : : * 'relids' is the 'em_relids' for the new member.
653 : : * 'jdomain' is the 'em_jdomain' for the new member.
654 : : * 'parent_em' is the parent member of the child to create.
655 : : * 'datatype' is the em_datatype of the new member.
656 : : * 'child_relid' defines which element of ec_childmembers to add this member
657 : : * to. This is generally a RELOPT_OTHER_MEMBER_REL, but for set operations
658 : : * can be a RELOPT_BASEREL representing the set-op children.
659 : : */
660 : : static EquivalenceMember *
661 : 14232 : add_child_eq_member(PlannerInfo *root, EquivalenceClass *ec, int ec_index,
662 : : Expr *expr, Relids relids, JoinDomain *jdomain,
663 : : EquivalenceMember *parent_em, Oid datatype,
664 : : Index child_relid)
665 : : {
666 : 14232 : EquivalenceMember *em;
667 : :
668 [ + - ]: 14232 : Assert(parent_em != NULL);
669 : :
670 : : /*
671 : : * Allocate the array to store child members; an array of Lists indexed by
672 : : * relid, or expand the existing one, if necessary.
673 : : */
674 [ + + ]: 14232 : if (unlikely(ec->ec_childmembers_size < root->simple_rel_array_size))
675 : : {
676 [ - + ]: 4224 : if (ec->ec_childmembers == NULL)
677 : 4224 : ec->ec_childmembers = palloc0_array(List *, root->simple_rel_array_size);
678 : : else
679 : 0 : ec->ec_childmembers = repalloc0_array(ec->ec_childmembers, List *,
680 : : ec->ec_childmembers_size,
681 : : root->simple_rel_array_size);
682 : :
683 : 4224 : ec->ec_childmembers_size = root->simple_rel_array_size;
684 : 4224 : }
685 : :
686 : 14232 : em = make_eq_member(ec, expr, relids, jdomain, parent_em, datatype);
687 : :
688 : : /* add member to the ec_childmembers List for the given child_relid */
689 : 14232 : ec->ec_childmembers[child_relid] = lappend(ec->ec_childmembers[child_relid], em);
690 : :
691 : : /* Record this EC index for the child rel */
692 [ + + ]: 14232 : if (ec_index >= 0)
693 : : {
694 : 8282 : RelOptInfo *child_rel = root->simple_rel_array[child_relid];
695 : :
696 : 8282 : child_rel->eclass_indexes =
697 : 8282 : bms_add_member(child_rel->eclass_indexes, ec_index);
698 : 8282 : }
699 : :
700 : 28464 : return em;
701 : 14232 : }
702 : :
703 : :
704 : : /*
705 : : * get_eclass_for_sort_expr
706 : : * Given an expression and opfamily/collation info, find an existing
707 : : * equivalence class it is a member of; if none, optionally build a new
708 : : * single-member EquivalenceClass for it.
709 : : *
710 : : * sortref is the SortGroupRef of the originating SortGroupClause, if any,
711 : : * or zero if not. (It should never be zero if the expression is volatile!)
712 : : *
713 : : * If rel is not NULL, it identifies a specific relation we're considering
714 : : * a path for, and indicates that child EC members for that relation can be
715 : : * considered. Otherwise child members are ignored. (Note: since child EC
716 : : * members aren't guaranteed unique, a non-NULL value means that there could
717 : : * be more than one EC that matches the expression; if so it's order-dependent
718 : : * which one you get. This is annoying but it only happens in corner cases,
719 : : * so for now we live with just reporting the first match. See also
720 : : * generate_implied_equalities_for_column and match_pathkeys_to_index.)
721 : : *
722 : : * If create_it is true, we'll build a new EquivalenceClass when there is no
723 : : * match. If create_it is false, we just return NULL when no match.
724 : : *
725 : : * This can be used safely both before and after EquivalenceClass merging;
726 : : * since it never causes merging it does not invalidate any existing ECs
727 : : * or PathKeys. However, ECs added after path generation has begun are
728 : : * of limited usefulness, so usually it's best to create them beforehand.
729 : : *
730 : : * Note: opfamilies must be chosen consistently with the way
731 : : * process_equivalence() would do; that is, generated from a mergejoinable
732 : : * equality operator. Else we might fail to detect valid equivalences,
733 : : * generating poor (but not incorrect) plans.
734 : : */
735 : : EquivalenceClass *
736 : 217637 : get_eclass_for_sort_expr(PlannerInfo *root,
737 : : Expr *expr,
738 : : List *opfamilies,
739 : : Oid opcintype,
740 : : Oid collation,
741 : : Index sortref,
742 : : Relids rel,
743 : : bool create_it)
744 : : {
745 : 217637 : JoinDomain *jdomain;
746 : 217637 : Relids expr_relids;
747 : 217637 : EquivalenceClass *newec;
748 : 217637 : EquivalenceMember *newem;
749 : 217637 : ListCell *lc1;
750 : 217637 : MemoryContext oldcontext;
751 : :
752 : : /*
753 : : * Ensure the expression exposes the correct type and collation.
754 : : */
755 : 217637 : expr = canonicalize_ec_expression(expr, opcintype, collation);
756 : :
757 : : /*
758 : : * Since SortGroupClause nodes are top-level expressions (GROUP BY, ORDER
759 : : * BY, etc), they can be presumed to belong to the top JoinDomain.
760 : : */
761 : 217637 : jdomain = linitial_node(JoinDomain, root->join_domains);
762 : :
763 : : /*
764 : : * Scan through the existing EquivalenceClasses for a match
765 : : */
766 [ + + + + : 800955 : foreach(lc1, root->eq_classes)
+ + + + ]
767 : : {
768 : 583318 : EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
769 : 583318 : EquivalenceMemberIterator it;
770 : 583318 : EquivalenceMember *cur_em;
771 : :
772 : : /*
773 : : * Never match to a volatile EC, except when we are looking at another
774 : : * reference to the same volatile SortGroupClause.
775 : : */
776 [ + + + + ]: 583323 : if (cur_ec->ec_has_volatile &&
777 [ + + ]: 103 : (sortref == 0 || sortref != cur_ec->ec_sortref))
778 : 100 : continue;
779 : :
780 [ + + ]: 583218 : if (collation != cur_ec->ec_collation)
781 : 193081 : continue;
782 [ + + ]: 390137 : if (!equal(opfamilies, cur_ec->ec_opfamilies))
783 : 75996 : continue;
784 : :
785 : 314141 : setup_eclass_member_iterator(&it, cur_ec, rel);
786 [ + + ]: 675154 : while ((cur_em = eclass_member_iterator_next(&it)) != NULL)
787 : : {
788 : : /*
789 : : * Ignore child members unless they match the request.
790 : : */
791 [ + + + - ]: 482837 : if (cur_em->em_is_child &&
792 : 16681 : !bms_equal(cur_em->em_relids, rel))
793 : 0 : continue;
794 : :
795 : : /*
796 : : * Match constants only within the same JoinDomain (see
797 : : * optimizer/README).
798 : : */
799 [ + + + + ]: 482837 : if (cur_em->em_is_const && cur_em->em_jdomain != jdomain)
800 : 6458 : continue;
801 : :
802 [ + + + + ]: 476379 : if (opcintype == cur_em->em_datatype &&
803 : 473385 : equal(expr, cur_em->em_expr))
804 : 121824 : return cur_ec; /* Match! */
805 : : }
806 [ + + + ]: 583318 : }
807 : :
808 : : /* No match; does caller want a NULL result? */
809 [ + + ]: 95813 : if (!create_it)
810 : 66350 : return NULL;
811 : :
812 : : /*
813 : : * OK, build a new single-member EC
814 : : *
815 : : * Here, we must be sure that we construct the EC in the right context.
816 : : */
817 : 29463 : oldcontext = MemoryContextSwitchTo(root->planner_cxt);
818 : :
819 : 29463 : newec = makeNode(EquivalenceClass);
820 : 29463 : newec->ec_opfamilies = list_copy(opfamilies);
821 : 29463 : newec->ec_collation = collation;
822 : 29463 : newec->ec_childmembers_size = 0;
823 : 29463 : newec->ec_members = NIL;
824 : 29463 : newec->ec_childmembers = NULL;
825 : 29463 : newec->ec_sources = NIL;
826 : 29463 : newec->ec_derives_list = NIL;
827 : 29463 : newec->ec_derives_hash = NULL;
828 : 29463 : newec->ec_relids = NULL;
829 : 29463 : newec->ec_has_const = false;
830 : 29463 : newec->ec_has_volatile = contain_volatile_functions((Node *) expr);
831 : 29463 : newec->ec_broken = false;
832 : 29463 : newec->ec_sortref = sortref;
833 : 29463 : newec->ec_min_security = UINT_MAX;
834 : 29463 : newec->ec_max_security = 0;
835 : 29463 : newec->ec_merged = NULL;
836 : :
837 [ + + + - ]: 29463 : if (newec->ec_has_volatile && sortref == 0) /* should not happen */
838 [ # # # # ]: 0 : elog(ERROR, "volatile EquivalenceClass has no sortref");
839 : :
840 : : /*
841 : : * Get the precise set of relids appearing in the expression.
842 : : */
843 : 29463 : expr_relids = pull_varnos(root, (Node *) expr);
844 : :
845 : 58926 : newem = add_eq_member(newec, copyObject(expr), expr_relids,
846 : 29463 : jdomain, opcintype);
847 : :
848 : : /*
849 : : * add_eq_member doesn't check for volatile functions, set-returning
850 : : * functions, aggregates, or window functions, but such could appear in
851 : : * sort expressions; so we have to check whether its const-marking was
852 : : * correct.
853 : : */
854 [ + + ]: 29463 : if (newec->ec_has_const)
855 : : {
856 [ + + ]: 1361 : if (newec->ec_has_volatile ||
857 [ + + ]: 1342 : expression_returns_set((Node *) expr) ||
858 [ + + + + ]: 1317 : contain_agg_clause((Node *) expr) ||
859 : 1289 : contain_window_function((Node *) expr))
860 : : {
861 : 73 : newec->ec_has_const = false;
862 : 73 : newem->em_is_const = false;
863 : 73 : }
864 : 1361 : }
865 : :
866 : 29463 : root->eq_classes = lappend(root->eq_classes, newec);
867 : :
868 : : /*
869 : : * If EC merging is already complete, we have to mop up by adding the new
870 : : * EC to the eclass_indexes of the relation(s) mentioned in it.
871 : : */
872 [ + + ]: 29463 : if (root->ec_merging_done)
873 : : {
874 : 20220 : int ec_index = list_length(root->eq_classes) - 1;
875 : 20220 : int i = -1;
876 : :
877 [ + + ]: 38804 : while ((i = bms_next_member(newec->ec_relids, i)) > 0)
878 : : {
879 : 18584 : RelOptInfo *rel = root->simple_rel_array[i];
880 : :
881 : : /* ignore the RTE_GROUP RTE */
882 [ + + ]: 18584 : if (i == root->group_rtindex)
883 : 114 : continue;
884 : :
885 [ + + ]: 18470 : if (rel == NULL) /* must be an outer join */
886 : : {
887 [ - + ]: 960 : Assert(bms_is_member(i, root->outer_join_rels));
888 : 960 : continue;
889 : : }
890 : :
891 [ - + ]: 17510 : Assert(rel->reloptkind == RELOPT_BASEREL);
892 : :
893 : 35020 : rel->eclass_indexes = bms_add_member(rel->eclass_indexes,
894 : 17510 : ec_index);
895 [ - + + ]: 18584 : }
896 : 20220 : }
897 : :
898 : 29463 : MemoryContextSwitchTo(oldcontext);
899 : :
900 : 29463 : return newec;
901 : 217637 : }
902 : :
903 : : /*
904 : : * find_ec_member_matching_expr
905 : : * Locate an EquivalenceClass member matching the given expr, if any;
906 : : * return NULL if no match.
907 : : *
908 : : * "Matching" is defined as "equal after stripping RelabelTypes".
909 : : * This is used for identifying sort expressions, and we need to allow
910 : : * binary-compatible relabeling for some cases involving binary-compatible
911 : : * sort operators.
912 : : *
913 : : * Child EC members are ignored unless they belong to given 'relids'.
914 : : */
915 : : EquivalenceMember *
916 : 46631 : find_ec_member_matching_expr(EquivalenceClass *ec,
917 : : Expr *expr,
918 : : Relids relids)
919 : : {
920 : 46631 : EquivalenceMemberIterator it;
921 : 46631 : EquivalenceMember *em;
922 : :
923 : : /* We ignore binary-compatible relabeling on both ends */
924 [ - + + + ]: 50906 : while (expr && IsA(expr, RelabelType))
925 : 4275 : expr = ((RelabelType *) expr)->arg;
926 : :
927 : 46631 : setup_eclass_member_iterator(&it, ec, relids);
928 [ + + ]: 79517 : while ((em = eclass_member_iterator_next(&it)) != NULL)
929 : : {
930 : 51694 : Expr *emexpr;
931 : :
932 : : /*
933 : : * We shouldn't be trying to sort by an equivalence class that
934 : : * contains a constant, so no need to consider such cases any further.
935 : : */
936 [ - + ]: 51694 : if (em->em_is_const)
937 : 0 : continue;
938 : :
939 : : /*
940 : : * Ignore child members unless they belong to the requested rel.
941 : : */
942 [ + + + + ]: 51694 : if (em->em_is_child &&
943 : 2007 : !bms_is_subset(em->em_relids, relids))
944 : 678 : continue;
945 : :
946 : : /*
947 : : * Match if same expression (after stripping relabel).
948 : : */
949 : 51016 : emexpr = em->em_expr;
950 [ - + + + ]: 52096 : while (emexpr && IsA(emexpr, RelabelType))
951 : 1080 : emexpr = ((RelabelType *) emexpr)->arg;
952 : :
953 [ + + ]: 51016 : if (equal(emexpr, expr))
954 : 18808 : return em;
955 [ + + + ]: 51694 : }
956 : :
957 : 27823 : return NULL;
958 : 46631 : }
959 : :
960 : : /*
961 : : * find_computable_ec_member
962 : : * Locate an EquivalenceClass member that can be computed from the
963 : : * expressions appearing in "exprs"; return NULL if no match.
964 : : *
965 : : * "exprs" can be either a list of bare expression trees, or a list of
966 : : * TargetEntry nodes. Typically it will contain Vars and possibly Aggrefs
967 : : * and WindowFuncs; however, when considering an appendrel member the list
968 : : * could contain arbitrary expressions. We consider an EC member to be
969 : : * computable if all the Vars, PlaceHolderVars, Aggrefs, and WindowFuncs
970 : : * it needs are present in "exprs".
971 : : *
972 : : * There is some subtlety in that definition: for example, if an EC member is
973 : : * Var_A + 1 while what is in "exprs" is Var_A + 2, it's still computable.
974 : : * This works because in the final plan tree, the EC member's expression will
975 : : * be computed as part of the same plan node targetlist that is currently
976 : : * represented by "exprs". So if we have Var_A available for the existing
977 : : * tlist member, it must be OK to use it in the EC expression too.
978 : : *
979 : : * Unlike find_ec_member_matching_expr, there's no special provision here
980 : : * for binary-compatible relabeling. This is intentional: if we have to
981 : : * compute an expression in this way, setrefs.c is going to insist on exact
982 : : * matches of Vars to the source tlist.
983 : : *
984 : : * Child EC members are ignored unless they belong to given 'relids'.
985 : : * Also, non-parallel-safe expressions are ignored if 'require_parallel_safe'.
986 : : *
987 : : * Note: some callers pass root == NULL for notational reasons. This is OK
988 : : * when require_parallel_safe is false.
989 : : */
990 : : EquivalenceMember *
991 : 1361 : find_computable_ec_member(PlannerInfo *root,
992 : : EquivalenceClass *ec,
993 : : List *exprs,
994 : : Relids relids,
995 : : bool require_parallel_safe)
996 : : {
997 : 1361 : List *exprvars;
998 : 1361 : EquivalenceMemberIterator it;
999 : 1361 : EquivalenceMember *em;
1000 : :
1001 : : /*
1002 : : * Pull out the Vars and quasi-Vars present in "exprs". In the typical
1003 : : * non-appendrel case, this is just another representation of the same
1004 : : * list. However, it does remove the distinction between the case of a
1005 : : * list of plain expressions and a list of TargetEntrys.
1006 : : */
1007 : 1361 : exprvars = pull_var_clause((Node *) exprs,
1008 : : PVC_INCLUDE_AGGREGATES |
1009 : : PVC_INCLUDE_WINDOWFUNCS |
1010 : : PVC_INCLUDE_PLACEHOLDERS);
1011 : :
1012 : 1361 : setup_eclass_member_iterator(&it, ec, relids);
1013 [ + + ]: 2729 : while ((em = eclass_member_iterator_next(&it)) != NULL)
1014 : : {
1015 : 1454 : List *emvars;
1016 : 1454 : ListCell *lc2;
1017 : :
1018 : : /*
1019 : : * We shouldn't be trying to sort by an equivalence class that
1020 : : * contains a constant, so no need to consider such cases any further.
1021 : : */
1022 [ - + ]: 1454 : if (em->em_is_const)
1023 : 0 : continue;
1024 : :
1025 : : /*
1026 : : * Ignore child members unless they belong to the requested rel.
1027 : : */
1028 [ + + + + ]: 1454 : if (em->em_is_child &&
1029 : 54 : !bms_is_subset(em->em_relids, relids))
1030 : 22 : continue;
1031 : :
1032 : : /*
1033 : : * Match if all Vars and quasi-Vars are present in "exprs".
1034 : : */
1035 : 1432 : emvars = pull_var_clause((Node *) em->em_expr,
1036 : : PVC_INCLUDE_AGGREGATES |
1037 : : PVC_INCLUDE_WINDOWFUNCS |
1038 : : PVC_INCLUDE_PLACEHOLDERS);
1039 [ + + + + : 2896 : foreach(lc2, emvars)
+ + ]
1040 : : {
1041 [ + + ]: 1464 : if (!list_member(exprvars, lfirst(lc2)))
1042 : 1341 : break;
1043 : 123 : }
1044 : 1432 : list_free(emvars);
1045 [ + + ]: 1432 : if (lc2)
1046 : 1341 : continue; /* we hit a non-available Var */
1047 : :
1048 : : /*
1049 : : * If requested, reject expressions that are not parallel-safe. We
1050 : : * check this last because it's a rather expensive test.
1051 : : */
1052 [ + + + + ]: 91 : if (require_parallel_safe &&
1053 : 21 : !is_parallel_safe(root, (Node *) em->em_expr))
1054 : 5 : continue;
1055 : :
1056 : 86 : return em; /* found usable expression */
1057 [ + + ]: 1454 : }
1058 : :
1059 : 1275 : return NULL;
1060 : 1361 : }
1061 : :
1062 : : /*
1063 : : * relation_can_be_sorted_early
1064 : : * Can this relation be sorted on this EC before the final output step?
1065 : : *
1066 : : * To succeed, we must find an EC member that prepare_sort_from_pathkeys knows
1067 : : * how to sort on, given the rel's reltarget as input. There are also a few
1068 : : * additional constraints based on the fact that the desired sort will be done
1069 : : * "early", within the scan/join part of the plan. Also, non-parallel-safe
1070 : : * expressions are ignored if 'require_parallel_safe'.
1071 : : *
1072 : : * At some point we might want to return the identified EquivalenceMember,
1073 : : * but for now, callers only want to know if there is one.
1074 : : */
1075 : : bool
1076 : 3009 : relation_can_be_sorted_early(PlannerInfo *root, RelOptInfo *rel,
1077 : : EquivalenceClass *ec, bool require_parallel_safe)
1078 : : {
1079 : 3009 : PathTarget *target = rel->reltarget;
1080 : 3009 : EquivalenceMember *em;
1081 : 3009 : ListCell *lc;
1082 : :
1083 : : /*
1084 : : * Reject volatile ECs immediately; such sorts must always be postponed.
1085 : : */
1086 [ + + ]: 3009 : if (ec->ec_has_volatile)
1087 : 12 : return false;
1088 : :
1089 : : /*
1090 : : * Try to find an EM directly matching some reltarget member.
1091 : : */
1092 [ + + + + : 8149 : foreach(lc, target->exprs)
+ + + + ]
1093 : : {
1094 : 5152 : Expr *targetexpr = (Expr *) lfirst(lc);
1095 : :
1096 : 5152 : em = find_ec_member_matching_expr(ec, targetexpr, rel->relids);
1097 [ + + ]: 5152 : if (!em)
1098 : 3446 : continue;
1099 : :
1100 : : /*
1101 : : * Reject expressions involving set-returning functions, as those
1102 : : * can't be computed early either. (Note: this test and the following
1103 : : * one are effectively checking properties of targetexpr, so there's
1104 : : * no point in asking whether some other EC member would be better.)
1105 : : */
1106 [ - + ]: 1706 : if (expression_returns_set((Node *) em->em_expr))
1107 : 0 : continue;
1108 : :
1109 : : /*
1110 : : * If requested, reject expressions that are not parallel-safe. We
1111 : : * check this last because it's a rather expensive test.
1112 : : */
1113 [ + - + - ]: 1706 : if (require_parallel_safe &&
1114 : 1706 : !is_parallel_safe(root, (Node *) em->em_expr))
1115 : 0 : continue;
1116 : :
1117 : 1706 : return true;
1118 [ + + ]: 5152 : }
1119 : :
1120 : : /*
1121 : : * Try to find an expression computable from the reltarget.
1122 : : */
1123 : 2582 : em = find_computable_ec_member(root, ec, target->exprs, rel->relids,
1124 : 1291 : require_parallel_safe);
1125 [ + + ]: 1291 : if (!em)
1126 : 1275 : return false;
1127 : :
1128 : : /*
1129 : : * Reject expressions involving set-returning functions, as those can't be
1130 : : * computed early either. (There's no point in looking for another EC
1131 : : * member in this case; since SRFs can't appear in WHERE, they cannot
1132 : : * belong to multi-member ECs.)
1133 : : */
1134 [ + + ]: 16 : if (expression_returns_set((Node *) em->em_expr))
1135 : 2 : return false;
1136 : :
1137 : 14 : return true;
1138 : 3009 : }
1139 : :
1140 : : /*
1141 : : * generate_base_implied_equalities
1142 : : * Generate any restriction clauses that we can deduce from equivalence
1143 : : * classes.
1144 : : *
1145 : : * When an EC contains pseudoconstants, our strategy is to generate
1146 : : * "member = const1" clauses where const1 is the first constant member, for
1147 : : * every other member (including other constants). If we are able to do this
1148 : : * then we don't need any "var = var" comparisons because we've successfully
1149 : : * constrained all the vars at their points of creation. If we fail to
1150 : : * generate any of these clauses due to lack of cross-type operators, we fall
1151 : : * back to the "ec_broken" strategy described below. (XXX if there are
1152 : : * multiple constants of different types, it's possible that we might succeed
1153 : : * in forming all the required clauses if we started from a different const
1154 : : * member; but this seems a sufficiently hokey corner case to not be worth
1155 : : * spending lots of cycles on.)
1156 : : *
1157 : : * For ECs that contain no pseudoconstants, we generate derived clauses
1158 : : * "member1 = member2" for each pair of members belonging to the same base
1159 : : * relation (actually, if there are more than two for the same base relation,
1160 : : * we only need enough clauses to link each to each other). This provides
1161 : : * the base case for the recursion: each row emitted by a base relation scan
1162 : : * will constrain all computable members of the EC to be equal. As each
1163 : : * join path is formed, we'll add additional derived clauses on-the-fly
1164 : : * to maintain this invariant (see generate_join_implied_equalities).
1165 : : *
1166 : : * If the opfamilies used by the EC do not provide complete sets of cross-type
1167 : : * equality operators, it is possible that we will fail to generate a clause
1168 : : * that must be generated to maintain the invariant. (An example: given
1169 : : * "WHERE a.x = b.y AND b.y = a.z", the scheme breaks down if we cannot
1170 : : * generate "a.x = a.z" as a restriction clause for A.) In this case we mark
1171 : : * the EC "ec_broken" and fall back to regurgitating its original source
1172 : : * RestrictInfos at appropriate times. We do not try to retract any derived
1173 : : * clauses already generated from the broken EC, so the resulting plan could
1174 : : * be poor due to bad selectivity estimates caused by redundant clauses. But
1175 : : * the correct solution to that is to fix the opfamilies ...
1176 : : *
1177 : : * Equality clauses derived by this function are passed off to
1178 : : * process_implied_equality (in plan/initsplan.c) to be inserted into the
1179 : : * restrictinfo datastructures. Note that this must be called after initial
1180 : : * scanning of the quals and before Path construction begins.
1181 : : *
1182 : : * We make no attempt to avoid generating duplicate RestrictInfos here: we
1183 : : * don't search existing source or derived clauses in the EC for matches. It
1184 : : * doesn't really seem worth the trouble to do so.
1185 : : */
1186 : : void
1187 : 33901 : generate_base_implied_equalities(PlannerInfo *root)
1188 : : {
1189 : 33901 : int ec_index;
1190 : 33901 : ListCell *lc;
1191 : :
1192 : : /*
1193 : : * At this point, we're done absorbing knowledge of equivalences in the
1194 : : * query, so no further EC merging should happen, and ECs remaining in the
1195 : : * eq_classes list can be considered canonical. (But note that it's still
1196 : : * possible for new single-member ECs to be added through
1197 : : * get_eclass_for_sort_expr().)
1198 : : */
1199 : 33901 : root->ec_merging_done = true;
1200 : :
1201 : 33901 : ec_index = 0;
1202 [ + + + + : 69298 : foreach(lc, root->eq_classes)
+ + ]
1203 : : {
1204 : 35397 : EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc);
1205 : 35397 : bool can_generate_joinclause = false;
1206 : 35397 : int i;
1207 : :
1208 [ - + ]: 35397 : Assert(ec->ec_merged == NULL); /* else shouldn't be in list */
1209 [ - + ]: 35397 : Assert(!ec->ec_broken); /* not yet anyway... */
1210 : :
1211 : : /*
1212 : : * Generate implied equalities that are restriction clauses.
1213 : : * Single-member ECs won't generate any deductions, either here or at
1214 : : * the join level.
1215 : : */
1216 [ + + ]: 35397 : if (list_length(ec->ec_members) > 1)
1217 : : {
1218 [ + + ]: 26361 : if (ec->ec_has_const)
1219 : 19268 : generate_base_implied_equalities_const(root, ec);
1220 : : else
1221 : 7093 : generate_base_implied_equalities_no_const(root, ec);
1222 : :
1223 : : /* Recover if we failed to generate required derived clauses */
1224 [ + + ]: 26361 : if (ec->ec_broken)
1225 : 5 : generate_base_implied_equalities_broken(root, ec);
1226 : :
1227 : : /* Detect whether this EC might generate join clauses */
1228 : 26361 : can_generate_joinclause =
1229 : 26361 : (bms_membership(ec->ec_relids) == BMS_MULTIPLE);
1230 : 26361 : }
1231 : :
1232 : : /*
1233 : : * Mark the base rels cited in each eclass (which should all exist by
1234 : : * now) with the eq_classes indexes of all eclasses mentioning them.
1235 : : * This will let us avoid searching in subsequent lookups. While
1236 : : * we're at it, we can mark base rels that have pending eclass joins;
1237 : : * this is a cheap version of has_relevant_eclass_joinclause().
1238 : : */
1239 : 35397 : i = -1;
1240 [ + + ]: 79374 : while ((i = bms_next_member(ec->ec_relids, i)) > 0)
1241 : : {
1242 : 43977 : RelOptInfo *rel = root->simple_rel_array[i];
1243 : :
1244 : : /* ignore the RTE_GROUP RTE */
1245 [ - + ]: 43977 : if (i == root->group_rtindex)
1246 : 0 : continue;
1247 : :
1248 [ + + ]: 43977 : if (rel == NULL) /* must be an outer join */
1249 : : {
1250 [ - + ]: 178 : Assert(bms_is_member(i, root->outer_join_rels));
1251 : 178 : continue;
1252 : : }
1253 : :
1254 [ - + ]: 43799 : Assert(rel->reloptkind == RELOPT_BASEREL);
1255 : :
1256 : 87598 : rel->eclass_indexes = bms_add_member(rel->eclass_indexes,
1257 : 43799 : ec_index);
1258 : :
1259 [ + + ]: 43799 : if (can_generate_joinclause)
1260 : 16744 : rel->has_eclass_joins = true;
1261 [ - + + ]: 43977 : }
1262 : :
1263 : 35397 : ec_index++;
1264 : 35397 : }
1265 : 33901 : }
1266 : :
1267 : : /*
1268 : : * generate_base_implied_equalities when EC contains pseudoconstant(s)
1269 : : */
1270 : : static void
1271 : 19268 : generate_base_implied_equalities_const(PlannerInfo *root,
1272 : : EquivalenceClass *ec)
1273 : : {
1274 : 19268 : EquivalenceMember *const_em = NULL;
1275 : 19268 : ListCell *lc;
1276 : :
1277 : : /*
1278 : : * In the trivial case where we just had one "var = const" clause, push
1279 : : * the original clause back into the main planner machinery. There is
1280 : : * nothing to be gained by doing it differently, and we save the effort to
1281 : : * re-build and re-analyze an equality clause that will be exactly
1282 : : * equivalent to the old one.
1283 : : */
1284 [ + + - + ]: 19268 : if (list_length(ec->ec_members) == 2 &&
1285 : 17847 : list_length(ec->ec_sources) == 1)
1286 : : {
1287 : 17847 : RestrictInfo *restrictinfo = (RestrictInfo *) linitial(ec->ec_sources);
1288 : :
1289 : 17847 : distribute_restrictinfo_to_rels(root, restrictinfo);
1290 : : return;
1291 : 17847 : }
1292 : :
1293 : : /* We don't expect any children yet */
1294 [ + - ]: 1421 : Assert(ec->ec_childmembers == NULL);
1295 : :
1296 : : /*
1297 : : * Find the constant member to use. We prefer an actual constant to
1298 : : * pseudo-constants (such as Params), because the constraint exclusion
1299 : : * machinery might be able to exclude relations on the basis of generated
1300 : : * "var = const" equalities, but "var = param" won't work for that.
1301 : : */
1302 [ + - + + : 5218 : foreach(lc, ec->ec_members)
+ + ]
1303 : : {
1304 : 3797 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
1305 : :
1306 [ + + ]: 3797 : if (cur_em->em_is_const)
1307 : : {
1308 : 1422 : const_em = cur_em;
1309 [ + + ]: 1422 : if (IsA(cur_em->em_expr, Const))
1310 : 1410 : break;
1311 : 12 : }
1312 [ + + ]: 3797 : }
1313 [ + - ]: 1421 : Assert(const_em != NULL);
1314 : :
1315 : : /* Generate a derived equality against each other member */
1316 [ + - + + : 5715 : foreach(lc, ec->ec_members)
+ + ]
1317 : : {
1318 : 4294 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
1319 : 4294 : Oid eq_op;
1320 : 4294 : RestrictInfo *rinfo;
1321 : :
1322 : : /* Child members should not exist in ec_members */
1323 [ + - ]: 4294 : Assert(!cur_em->em_is_child);
1324 [ + + ]: 4294 : if (cur_em == const_em)
1325 : 1417 : continue;
1326 : 5754 : eq_op = select_equality_operator(ec,
1327 : 2877 : cur_em->em_datatype,
1328 : 2877 : const_em->em_datatype);
1329 [ + + ]: 2877 : if (!OidIsValid(eq_op))
1330 : : {
1331 : : /* failed... */
1332 : 5 : ec->ec_broken = true;
1333 : 5 : break;
1334 : : }
1335 : :
1336 : : /*
1337 : : * We use the constant's em_jdomain as qualscope, so that if the
1338 : : * generated clause is variable-free (i.e, both EMs are consts) it
1339 : : * will be enforced at the join domain level.
1340 : : */
1341 : 5744 : rinfo = process_implied_equality(root, eq_op, ec->ec_collation,
1342 : 2872 : cur_em->em_expr, const_em->em_expr,
1343 : 2872 : const_em->em_jdomain->jd_relids,
1344 : 2872 : ec->ec_min_security,
1345 : 2872 : cur_em->em_is_const);
1346 : :
1347 : : /*
1348 : : * If the clause didn't degenerate to a constant, fill in the correct
1349 : : * markings for a mergejoinable clause, and save it as a derived
1350 : : * clause. (We will not re-use such clauses directly, but selectivity
1351 : : * estimation may consult those later. Note that this use of derived
1352 : : * clauses does not overlap with its use for join clauses, since we
1353 : : * never generate join clauses from an ec_has_const eclass.)
1354 : : */
1355 [ + - + + ]: 2872 : if (rinfo && rinfo->mergeopfamilies)
1356 : : {
1357 : : /* it's not redundant, so don't set parent_ec */
1358 : 2850 : rinfo->left_ec = rinfo->right_ec = ec;
1359 : 2850 : rinfo->left_em = cur_em;
1360 : 2850 : rinfo->right_em = const_em;
1361 : 2850 : ec_add_derived_clause(ec, rinfo);
1362 : 2850 : }
1363 [ + + + ]: 4294 : }
1364 [ - + ]: 19268 : }
1365 : :
1366 : : /*
1367 : : * generate_base_implied_equalities when EC contains no pseudoconstants
1368 : : */
1369 : : static void
1370 : 7093 : generate_base_implied_equalities_no_const(PlannerInfo *root,
1371 : : EquivalenceClass *ec)
1372 : : {
1373 : 7093 : EquivalenceMember **prev_ems;
1374 : 7093 : ListCell *lc;
1375 : :
1376 : : /*
1377 : : * We scan the EC members once and track the last-seen member for each
1378 : : * base relation. When we see another member of the same base relation,
1379 : : * we generate "prev_em = cur_em". This results in the minimum number of
1380 : : * derived clauses, but it's possible that it will fail when a different
1381 : : * ordering would succeed. XXX FIXME: use a UNION-FIND algorithm similar
1382 : : * to the way we build merged ECs. (Use a list-of-lists for each rel.)
1383 : : */
1384 : 7093 : prev_ems = (EquivalenceMember **)
1385 : 7093 : palloc0(root->simple_rel_array_size * sizeof(EquivalenceMember *));
1386 : :
1387 : : /* We don't expect any children yet */
1388 [ + - ]: 7093 : Assert(ec->ec_childmembers == NULL);
1389 : :
1390 [ + - + + : 21452 : foreach(lc, ec->ec_members)
+ + ]
1391 : : {
1392 : 14359 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
1393 : 14359 : int relid;
1394 : :
1395 : : /* Child members should not exist in ec_members */
1396 [ + - ]: 14359 : Assert(!cur_em->em_is_child);
1397 : :
1398 [ + + ]: 14359 : if (!bms_get_singleton_member(cur_em->em_relids, &relid))
1399 : 33 : continue;
1400 [ + - ]: 14326 : Assert(relid < root->simple_rel_array_size);
1401 : :
1402 [ + + ]: 14326 : if (prev_ems[relid] != NULL)
1403 : : {
1404 : 70 : EquivalenceMember *prev_em = prev_ems[relid];
1405 : 70 : Oid eq_op;
1406 : 70 : RestrictInfo *rinfo;
1407 : :
1408 : 140 : eq_op = select_equality_operator(ec,
1409 : 70 : prev_em->em_datatype,
1410 : 70 : cur_em->em_datatype);
1411 [ + - ]: 70 : if (!OidIsValid(eq_op))
1412 : : {
1413 : : /* failed... */
1414 : 0 : ec->ec_broken = true;
1415 : 0 : break;
1416 : : }
1417 : :
1418 : : /*
1419 : : * The expressions aren't constants, so the passed qualscope will
1420 : : * never be used to place the generated clause. We just need to
1421 : : * be sure it covers both expressions, which em_relids should do.
1422 : : */
1423 : 140 : rinfo = process_implied_equality(root, eq_op, ec->ec_collation,
1424 : 70 : prev_em->em_expr, cur_em->em_expr,
1425 : 70 : cur_em->em_relids,
1426 : 70 : ec->ec_min_security,
1427 : : false);
1428 : :
1429 : : /*
1430 : : * If the clause didn't degenerate to a constant, fill in the
1431 : : * correct markings for a mergejoinable clause. We don't record
1432 : : * it as a derived clause, since we don't currently need to
1433 : : * re-find such clauses, and don't want to clutter the
1434 : : * derived-clause set with non-join clauses.
1435 : : */
1436 [ + - - + ]: 70 : if (rinfo && rinfo->mergeopfamilies)
1437 : : {
1438 : : /* it's not redundant, so don't set parent_ec */
1439 : 70 : rinfo->left_ec = rinfo->right_ec = ec;
1440 : 70 : rinfo->left_em = prev_em;
1441 : 70 : rinfo->right_em = cur_em;
1442 : 70 : }
1443 [ - + ]: 70 : }
1444 : 14326 : prev_ems[relid] = cur_em;
1445 [ + - + ]: 14359 : }
1446 : :
1447 : 7093 : pfree(prev_ems);
1448 : :
1449 : : /*
1450 : : * We also have to make sure that all the Vars used in the member clauses
1451 : : * will be available at any join node we might try to reference them at.
1452 : : * For the moment we force all the Vars to be available at all join nodes
1453 : : * for this eclass. Perhaps this could be improved by doing some
1454 : : * pre-analysis of which members we prefer to join, but it's no worse than
1455 : : * what happened in the pre-8.3 code. (Note: rebuild_eclass_attr_needed
1456 : : * needs to match this code.)
1457 : : */
1458 [ + - + + : 21452 : foreach(lc, ec->ec_members)
+ + ]
1459 : : {
1460 : 14359 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
1461 : 14359 : List *vars = pull_var_clause((Node *) cur_em->em_expr,
1462 : : PVC_RECURSE_AGGREGATES |
1463 : : PVC_RECURSE_WINDOWFUNCS |
1464 : : PVC_INCLUDE_PLACEHOLDERS);
1465 : :
1466 : 14359 : add_vars_to_targetlist(root, vars, ec->ec_relids);
1467 : 14359 : list_free(vars);
1468 : 14359 : }
1469 : 7093 : }
1470 : :
1471 : : /*
1472 : : * generate_base_implied_equalities cleanup after failure
1473 : : *
1474 : : * What we must do here is push any zero- or one-relation source RestrictInfos
1475 : : * of the EC back into the main restrictinfo datastructures. Multi-relation
1476 : : * clauses will be regurgitated later by generate_join_implied_equalities().
1477 : : * (We do it this way to maintain continuity with the case that ec_broken
1478 : : * becomes set only after we've gone up a join level or two.) However, for
1479 : : * an EC that contains constants, we can adopt a simpler strategy and just
1480 : : * throw back all the source RestrictInfos immediately; that works because
1481 : : * we know that such an EC can't become broken later. (This rule justifies
1482 : : * ignoring ec_has_const ECs in generate_join_implied_equalities, even when
1483 : : * they are broken.)
1484 : : */
1485 : : static void
1486 : 5 : generate_base_implied_equalities_broken(PlannerInfo *root,
1487 : : EquivalenceClass *ec)
1488 : : {
1489 : 5 : ListCell *lc;
1490 : :
1491 [ + - + + : 16 : foreach(lc, ec->ec_sources)
+ + ]
1492 : : {
1493 : 11 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(lc);
1494 : :
1495 [ - + # # ]: 11 : if (ec->ec_has_const ||
1496 : 0 : bms_membership(restrictinfo->required_relids) != BMS_MULTIPLE)
1497 : 11 : distribute_restrictinfo_to_rels(root, restrictinfo);
1498 : 11 : }
1499 : 5 : }
1500 : :
1501 : :
1502 : : /*
1503 : : * generate_join_implied_equalities
1504 : : * Generate any join clauses that we can deduce from equivalence classes.
1505 : : *
1506 : : * At a join node, we must enforce restriction clauses sufficient to ensure
1507 : : * that all equivalence-class members computable at that node are equal.
1508 : : * Since the set of clauses to enforce can vary depending on which subset
1509 : : * relations are the inputs, we have to compute this afresh for each join
1510 : : * relation pair. Hence a fresh List of RestrictInfo nodes is built and
1511 : : * passed back on each call.
1512 : : *
1513 : : * In addition to its use at join nodes, this can be applied to generate
1514 : : * eclass-based join clauses for use in a parameterized scan of a base rel.
1515 : : * The reason for the asymmetry of specifying the inner rel as a RelOptInfo
1516 : : * and the outer rel by Relids is that this usage occurs before we have
1517 : : * built any join RelOptInfos.
1518 : : *
1519 : : * An annoying special case for parameterized scans is that the inner rel can
1520 : : * be an appendrel child (an "other rel"). In this case we must generate
1521 : : * appropriate clauses using child EC members. add_child_rel_equivalences
1522 : : * must already have been done for the child rel.
1523 : : *
1524 : : * The results are sufficient for use in merge, hash, and plain nestloop join
1525 : : * methods. We do not worry here about selecting clauses that are optimal
1526 : : * for use in a parameterized indexscan. indxpath.c makes its own selections
1527 : : * of clauses to use, and if the ones we pick here are redundant with those,
1528 : : * the extras will be eliminated at createplan time, using the parent_ec
1529 : : * markers that we provide (see is_redundant_derived_clause()).
1530 : : *
1531 : : * Because the same join clauses are likely to be needed multiple times as
1532 : : * we consider different join paths, we avoid generating multiple copies:
1533 : : * whenever we select a particular pair of EquivalenceMembers to join,
1534 : : * we check to see if the pair matches any original clause (in ec_sources)
1535 : : * or previously-built derived clause. This saves memory and allows
1536 : : * re-use of information cached in RestrictInfos. We also avoid generating
1537 : : * commutative duplicates, i.e. if the algorithm selects "a.x = b.y" but
1538 : : * we already have "b.y = a.x", we return the existing clause.
1539 : : *
1540 : : * If we are considering an outer join, sjinfo is the associated OJ info,
1541 : : * otherwise it can be NULL.
1542 : : *
1543 : : * join_relids should always equal bms_union(outer_relids, inner_rel->relids)
1544 : : * plus whatever add_outer_joins_to_relids() would add. We could simplify
1545 : : * this function's API by computing it internally, but most callers have the
1546 : : * value at hand anyway.
1547 : : */
1548 : : List *
1549 : 44512 : generate_join_implied_equalities(PlannerInfo *root,
1550 : : Relids join_relids,
1551 : : Relids outer_relids,
1552 : : RelOptInfo *inner_rel,
1553 : : SpecialJoinInfo *sjinfo)
1554 : : {
1555 : 44512 : List *result = NIL;
1556 : 44512 : Relids inner_relids = inner_rel->relids;
1557 : 44512 : Relids nominal_inner_relids;
1558 : 44512 : Relids nominal_join_relids;
1559 : 44512 : Bitmapset *matching_ecs;
1560 : 44512 : int i;
1561 : :
1562 : : /* If inner rel is a child, extra setup work is needed */
1563 [ + + + + : 44512 : if (IS_OTHER_REL(inner_rel))
- + ]
1564 : : {
1565 [ + - ]: 1313 : Assert(!bms_is_empty(inner_rel->top_parent_relids));
1566 : :
1567 : : /* Fetch relid set for the topmost parent rel */
1568 : 1313 : nominal_inner_relids = inner_rel->top_parent_relids;
1569 : : /* ECs will be marked with the parent's relid, not the child's */
1570 : 1313 : nominal_join_relids = bms_union(outer_relids, nominal_inner_relids);
1571 : 2626 : nominal_join_relids = add_outer_joins_to_relids(root,
1572 : 1313 : nominal_join_relids,
1573 : 1313 : sjinfo,
1574 : : NULL);
1575 : 1313 : }
1576 : : else
1577 : : {
1578 : 43199 : nominal_inner_relids = inner_relids;
1579 : 43199 : nominal_join_relids = join_relids;
1580 : : }
1581 : :
1582 : : /*
1583 : : * Examine all potentially-relevant eclasses.
1584 : : *
1585 : : * If we are considering an outer join, we must include "join" clauses
1586 : : * that mention either input rel plus the outer join's relid; these
1587 : : * represent post-join filter clauses that have to be applied at this
1588 : : * join. We don't have infrastructure that would let us identify such
1589 : : * eclasses cheaply, so just fall back to considering all eclasses
1590 : : * mentioning anything in nominal_join_relids.
1591 : : *
1592 : : * At inner joins, we can be smarter: only consider eclasses mentioning
1593 : : * both input rels.
1594 : : */
1595 [ + + + + ]: 44512 : if (sjinfo && sjinfo->ojrelid != 0)
1596 : 5632 : matching_ecs = get_eclass_indexes_for_relids(root, nominal_join_relids);
1597 : : else
1598 : 77760 : matching_ecs = get_common_eclass_indexes(root, nominal_inner_relids,
1599 : 38880 : outer_relids);
1600 : :
1601 : 44512 : i = -1;
1602 [ + + ]: 109252 : while ((i = bms_next_member(matching_ecs, i)) >= 0)
1603 : : {
1604 : 64740 : EquivalenceClass *ec = (EquivalenceClass *) list_nth(root->eq_classes, i);
1605 : 64740 : List *sublist = NIL;
1606 : :
1607 : : /* ECs containing consts do not need any further enforcement */
1608 [ + + ]: 64740 : if (ec->ec_has_const)
1609 : 7423 : continue;
1610 : :
1611 : : /* Single-member ECs won't generate any deductions */
1612 [ + + ]: 57317 : if (list_length(ec->ec_members) <= 1)
1613 : 23470 : continue;
1614 : :
1615 : : /* Sanity check that this eclass overlaps the join */
1616 [ - + ]: 33847 : Assert(bms_overlap(ec->ec_relids, nominal_join_relids));
1617 : :
1618 [ + + ]: 33847 : if (!ec->ec_broken)
1619 : 67586 : sublist = generate_join_implied_equalities_normal(root,
1620 : 33793 : ec,
1621 : 33793 : join_relids,
1622 : 33793 : outer_relids,
1623 : 33793 : inner_relids);
1624 : :
1625 : : /* Recover if we failed to generate required derived clauses */
1626 [ + + ]: 33847 : if (ec->ec_broken)
1627 : 120 : sublist = generate_join_implied_equalities_broken(root,
1628 : 60 : ec,
1629 : 60 : nominal_join_relids,
1630 : 60 : outer_relids,
1631 : 60 : nominal_inner_relids,
1632 : 60 : inner_rel);
1633 : :
1634 : 33847 : result = list_concat(result, sublist);
1635 [ - + + ]: 64740 : }
1636 : :
1637 : 89024 : return result;
1638 : 44512 : }
1639 : :
1640 : : /*
1641 : : * generate_join_implied_equalities_for_ecs
1642 : : * As above, but consider only the listed ECs.
1643 : : *
1644 : : * For the sole current caller, we can assume sjinfo == NULL, that is we are
1645 : : * not interested in outer-join filter clauses. This might need to change
1646 : : * in future.
1647 : : */
1648 : : List *
1649 : 200 : generate_join_implied_equalities_for_ecs(PlannerInfo *root,
1650 : : List *eclasses,
1651 : : Relids join_relids,
1652 : : Relids outer_relids,
1653 : : RelOptInfo *inner_rel)
1654 : : {
1655 : 200 : List *result = NIL;
1656 : 200 : Relids inner_relids = inner_rel->relids;
1657 : 200 : Relids nominal_inner_relids;
1658 : 200 : Relids nominal_join_relids;
1659 : 200 : ListCell *lc;
1660 : :
1661 : : /* If inner rel is a child, extra setup work is needed */
1662 [ + + + - : 200 : if (IS_OTHER_REL(inner_rel))
- + ]
1663 : : {
1664 [ + - ]: 3 : Assert(!bms_is_empty(inner_rel->top_parent_relids));
1665 : :
1666 : : /* Fetch relid set for the topmost parent rel */
1667 : 3 : nominal_inner_relids = inner_rel->top_parent_relids;
1668 : : /* ECs will be marked with the parent's relid, not the child's */
1669 : 3 : nominal_join_relids = bms_union(outer_relids, nominal_inner_relids);
1670 : 3 : }
1671 : : else
1672 : : {
1673 : 197 : nominal_inner_relids = inner_relids;
1674 : 197 : nominal_join_relids = join_relids;
1675 : : }
1676 : :
1677 [ + - + + : 411 : foreach(lc, eclasses)
+ + ]
1678 : : {
1679 : 211 : EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc);
1680 : 211 : List *sublist = NIL;
1681 : :
1682 : : /* ECs containing consts do not need any further enforcement */
1683 [ - + ]: 211 : if (ec->ec_has_const)
1684 : 0 : continue;
1685 : :
1686 : : /* Single-member ECs won't generate any deductions */
1687 [ - + ]: 211 : if (list_length(ec->ec_members) <= 1)
1688 : 0 : continue;
1689 : :
1690 : : /* We can quickly ignore any that don't overlap the join, too */
1691 [ + - ]: 211 : if (!bms_overlap(ec->ec_relids, nominal_join_relids))
1692 : 0 : continue;
1693 : :
1694 [ - + ]: 211 : if (!ec->ec_broken)
1695 : 422 : sublist = generate_join_implied_equalities_normal(root,
1696 : 211 : ec,
1697 : 211 : join_relids,
1698 : 211 : outer_relids,
1699 : 211 : inner_relids);
1700 : :
1701 : : /* Recover if we failed to generate required derived clauses */
1702 [ + - ]: 211 : if (ec->ec_broken)
1703 : 0 : sublist = generate_join_implied_equalities_broken(root,
1704 : 0 : ec,
1705 : 0 : nominal_join_relids,
1706 : 0 : outer_relids,
1707 : 0 : nominal_inner_relids,
1708 : 0 : inner_rel);
1709 : :
1710 : 211 : result = list_concat(result, sublist);
1711 [ - - + ]: 211 : }
1712 : :
1713 : 400 : return result;
1714 : 200 : }
1715 : :
1716 : : /*
1717 : : * generate_join_implied_equalities for a still-valid EC
1718 : : */
1719 : : static List *
1720 : 34004 : generate_join_implied_equalities_normal(PlannerInfo *root,
1721 : : EquivalenceClass *ec,
1722 : : Relids join_relids,
1723 : : Relids outer_relids,
1724 : : Relids inner_relids)
1725 : : {
1726 : 34004 : List *result = NIL;
1727 : 34004 : List *new_members = NIL;
1728 : 34004 : List *outer_members = NIL;
1729 : 34004 : List *inner_members = NIL;
1730 : 34004 : EquivalenceMemberIterator it;
1731 : 34004 : EquivalenceMember *cur_em;
1732 : :
1733 : : /*
1734 : : * First, scan the EC to identify member values that are computable at the
1735 : : * outer rel, at the inner rel, or at this relation but not in either
1736 : : * input rel. The outer-rel members should already be enforced equal,
1737 : : * likewise for the inner-rel members. We'll need to create clauses to
1738 : : * enforce that any newly computable members are all equal to each other
1739 : : * as well as to at least one input member, plus enforce at least one
1740 : : * outer-rel member equal to at least one inner-rel member.
1741 : : */
1742 : 34004 : setup_eclass_member_iterator(&it, ec, join_relids);
1743 [ + + ]: 107835 : while ((cur_em = eclass_member_iterator_next(&it)) != NULL)
1744 : : {
1745 : : /*
1746 : : * We don't need to check explicitly for child EC members. This test
1747 : : * against join_relids will cause them to be ignored except when
1748 : : * considering a child inner rel, which is what we want.
1749 : : */
1750 [ + + ]: 73831 : if (!bms_is_subset(cur_em->em_relids, join_relids))
1751 : 5148 : continue; /* not computable yet, or wrong child */
1752 : :
1753 [ + + ]: 68683 : if (bms_is_subset(cur_em->em_relids, outer_relids))
1754 : 36504 : outer_members = lappend(outer_members, cur_em);
1755 [ + + ]: 32179 : else if (bms_is_subset(cur_em->em_relids, inner_relids))
1756 : 31791 : inner_members = lappend(inner_members, cur_em);
1757 : : else
1758 : 388 : new_members = lappend(new_members, cur_em);
1759 : : }
1760 : :
1761 : : /*
1762 : : * First, select the joinclause if needed. We can equate any one outer
1763 : : * member to any one inner member, but we have to find a datatype
1764 : : * combination for which an opfamily member operator exists. If we have
1765 : : * choices, we prefer simple Var members (possibly with RelabelType) since
1766 : : * these are (a) cheapest to compute at runtime and (b) most likely to
1767 : : * have useful statistics. Also, prefer operators that are also
1768 : : * hashjoinable.
1769 : : */
1770 [ + + + + ]: 34004 : if (outer_members && inner_members)
1771 : : {
1772 : 29917 : EquivalenceMember *best_outer_em = NULL;
1773 : 29917 : EquivalenceMember *best_inner_em = NULL;
1774 : 29917 : Oid best_eq_op = InvalidOid;
1775 : 29917 : int best_score = -1;
1776 : 29917 : RestrictInfo *rinfo;
1777 : 29917 : ListCell *lc1;
1778 : :
1779 [ + - + + : 59847 : foreach(lc1, outer_members)
+ + ]
1780 : : {
1781 : 29930 : EquivalenceMember *outer_em = (EquivalenceMember *) lfirst(lc1);
1782 : 29930 : ListCell *lc2;
1783 : :
1784 [ + - + + : 59864 : foreach(lc2, inner_members)
+ + ]
1785 : : {
1786 : 29934 : EquivalenceMember *inner_em = (EquivalenceMember *) lfirst(lc2);
1787 : 29934 : Oid eq_op;
1788 : 29934 : int score;
1789 : :
1790 : 59868 : eq_op = select_equality_operator(ec,
1791 : 29934 : outer_em->em_datatype,
1792 : 29934 : inner_em->em_datatype);
1793 [ + + ]: 29934 : if (!OidIsValid(eq_op))
1794 : 6 : continue;
1795 : 29928 : score = 0;
1796 [ + + + + ]: 30523 : if (IsA(outer_em->em_expr, Var) ||
1797 [ + + ]: 2632 : (IsA(outer_em->em_expr, RelabelType) &&
1798 : 595 : IsA(((RelabelType *) outer_em->em_expr)->arg, Var)))
1799 : 27875 : score++;
1800 [ + + + + ]: 31288 : if (IsA(inner_em->em_expr, Var) ||
1801 [ + + ]: 1779 : (IsA(inner_em->em_expr, RelabelType) &&
1802 : 1360 : IsA(((RelabelType *) inner_em->em_expr)->arg, Var)))
1803 : 29503 : score++;
1804 [ + + + + ]: 59856 : if (op_hashjoinable(eq_op,
1805 : 29928 : exprType((Node *) outer_em->em_expr)))
1806 : 29918 : score++;
1807 [ + + ]: 29928 : if (score > best_score)
1808 : : {
1809 : 29911 : best_outer_em = outer_em;
1810 : 29911 : best_inner_em = inner_em;
1811 : 29911 : best_eq_op = eq_op;
1812 : 29911 : best_score = score;
1813 [ + + ]: 29911 : if (best_score == 3)
1814 : 27519 : break; /* no need to look further */
1815 : 2392 : }
1816 [ + + + ]: 29934 : }
1817 [ + + ]: 29930 : if (best_score == 3)
1818 : 27519 : break; /* no need to look further */
1819 [ + + ]: 29930 : }
1820 [ + + ]: 29917 : if (best_score < 0)
1821 : : {
1822 : : /* failed... */
1823 : 6 : ec->ec_broken = true;
1824 : 6 : return NIL;
1825 : : }
1826 : :
1827 : : /*
1828 : : * Create clause, setting parent_ec to mark it as redundant with other
1829 : : * joinclauses
1830 : : */
1831 : 59822 : rinfo = create_join_clause(root, ec, best_eq_op,
1832 : 29911 : best_outer_em, best_inner_em,
1833 : 29911 : ec);
1834 : :
1835 : 29911 : result = lappend(result, rinfo);
1836 [ + + ]: 29917 : }
1837 : :
1838 : : /*
1839 : : * Now deal with building restrictions for any expressions that involve
1840 : : * Vars from both sides of the join. We have to equate all of these to
1841 : : * each other as well as to at least one old member (if any).
1842 : : *
1843 : : * XXX as in generate_base_implied_equalities_no_const, we could be a lot
1844 : : * smarter here to avoid unnecessary failures in cross-type situations.
1845 : : * For now, use the same left-to-right method used there.
1846 : : */
1847 [ + + ]: 33998 : if (new_members)
1848 : : {
1849 : 382 : List *old_members = list_concat(outer_members, inner_members);
1850 : 382 : EquivalenceMember *prev_em = NULL;
1851 : 382 : RestrictInfo *rinfo;
1852 : 382 : ListCell *lc1;
1853 : :
1854 : : /* For now, arbitrarily take the first old_member as the one to use */
1855 [ + + ]: 382 : if (old_members)
1856 : 325 : new_members = lappend(new_members, linitial(old_members));
1857 : :
1858 [ + - + + : 1095 : foreach(lc1, new_members)
+ + - + ]
1859 : : {
1860 : 713 : cur_em = (EquivalenceMember *) lfirst(lc1);
1861 : :
1862 [ + + ]: 713 : if (prev_em != NULL)
1863 : : {
1864 : 331 : Oid eq_op;
1865 : :
1866 : 662 : eq_op = select_equality_operator(ec,
1867 : 331 : prev_em->em_datatype,
1868 : 331 : cur_em->em_datatype);
1869 [ + - ]: 331 : if (!OidIsValid(eq_op))
1870 : : {
1871 : : /* failed... */
1872 : 0 : ec->ec_broken = true;
1873 : 0 : return NIL;
1874 : : }
1875 : : /* do NOT set parent_ec, this qual is not redundant! */
1876 : 662 : rinfo = create_join_clause(root, ec, eq_op,
1877 : 331 : prev_em, cur_em,
1878 : : NULL);
1879 : :
1880 : 331 : result = lappend(result, rinfo);
1881 [ - + ]: 331 : }
1882 : 713 : prev_em = cur_em;
1883 : 713 : }
1884 [ - + ]: 382 : }
1885 : :
1886 : 33998 : return result;
1887 : 34004 : }
1888 : :
1889 : : /*
1890 : : * generate_join_implied_equalities cleanup after failure
1891 : : *
1892 : : * Return any original RestrictInfos that are enforceable at this join.
1893 : : *
1894 : : * In the case of a child inner relation, we have to translate the
1895 : : * original RestrictInfos from parent to child Vars.
1896 : : */
1897 : : static List *
1898 : 60 : generate_join_implied_equalities_broken(PlannerInfo *root,
1899 : : EquivalenceClass *ec,
1900 : : Relids nominal_join_relids,
1901 : : Relids outer_relids,
1902 : : Relids nominal_inner_relids,
1903 : : RelOptInfo *inner_rel)
1904 : : {
1905 : 60 : List *result = NIL;
1906 : 60 : ListCell *lc;
1907 : :
1908 [ + - + + : 164 : foreach(lc, ec->ec_sources)
+ + ]
1909 : : {
1910 : 104 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(lc);
1911 : 104 : Relids clause_relids = restrictinfo->required_relids;
1912 : :
1913 [ + + ]: 104 : if (bms_is_subset(clause_relids, nominal_join_relids) &&
1914 [ + + - + ]: 56 : !bms_is_subset(clause_relids, outer_relids) &&
1915 : 52 : !bms_is_subset(clause_relids, nominal_inner_relids))
1916 : 52 : result = lappend(result, restrictinfo);
1917 : 104 : }
1918 : :
1919 : : /*
1920 : : * If we have to translate, just brute-force apply adjust_appendrel_attrs
1921 : : * to all the RestrictInfos at once. This will result in returning
1922 : : * RestrictInfos that are not included in EC's derived clauses, but there
1923 : : * shouldn't be any duplication, and it's a sufficiently narrow corner
1924 : : * case that we shouldn't sweat too much over it anyway.
1925 : : *
1926 : : * Since inner_rel might be an indirect descendant of the baserel
1927 : : * mentioned in the ec_sources clauses, we have to be prepared to apply
1928 : : * multiple levels of Var translation.
1929 : : */
1930 [ + + + - : 60 : if (IS_OTHER_REL(inner_rel) && result != NIL)
+ + ]
1931 : 54 : result = (List *) adjust_appendrel_attrs_multilevel(root,
1932 : 27 : (Node *) result,
1933 : 27 : inner_rel,
1934 : 27 : inner_rel->top_parent);
1935 : :
1936 : 120 : return result;
1937 : 60 : }
1938 : :
1939 : :
1940 : : /*
1941 : : * select_equality_operator
1942 : : * Select a suitable equality operator for comparing two EC members
1943 : : *
1944 : : * Returns InvalidOid if no operator can be found for this datatype combination
1945 : : */
1946 : : static Oid
1947 : 44984 : select_equality_operator(EquivalenceClass *ec, Oid lefttype, Oid righttype)
1948 : : {
1949 : 44984 : ListCell *lc;
1950 : :
1951 [ + - + + : 89968 : foreach(lc, ec->ec_opfamilies)
+ + + + ]
1952 : : {
1953 : 44984 : Oid opfamily = lfirst_oid(lc);
1954 : 44984 : Oid opno;
1955 : :
1956 : 44984 : opno = get_opfamily_member_for_cmptype(opfamily, lefttype, righttype, COMPARE_EQ);
1957 [ + + ]: 44984 : if (!OidIsValid(opno))
1958 : 11 : continue;
1959 : : /* If no barrier quals in query, don't worry about leaky operators */
1960 [ + + ]: 44973 : if (ec->ec_max_security == 0)
1961 : 44878 : return opno;
1962 : : /* Otherwise, insist that selected operators be leakproof */
1963 [ + - ]: 95 : if (get_func_leakproof(get_opcode(opno)))
1964 : 95 : return opno;
1965 [ + + - ]: 44984 : }
1966 : 11 : return InvalidOid;
1967 : 44984 : }
1968 : :
1969 : :
1970 : : /*
1971 : : * create_join_clause
1972 : : * Find or make a RestrictInfo comparing the two given EC members
1973 : : * with the given operator (or, possibly, its commutator, because
1974 : : * the ordering of the operands in the result is not guaranteed).
1975 : : *
1976 : : * parent_ec is either equal to ec (if the clause is a potentially-redundant
1977 : : * join clause) or NULL (if not). We have to treat this as part of the
1978 : : * match requirements --- it's possible that a clause comparing the same two
1979 : : * EMs is a join clause in one join path and a restriction clause in another.
1980 : : */
1981 : : static RestrictInfo *
1982 : 42604 : create_join_clause(PlannerInfo *root,
1983 : : EquivalenceClass *ec, Oid opno,
1984 : : EquivalenceMember *leftem,
1985 : : EquivalenceMember *rightem,
1986 : : EquivalenceClass *parent_ec)
1987 : : {
1988 : 42604 : RestrictInfo *rinfo;
1989 : 42604 : RestrictInfo *parent_rinfo = NULL;
1990 : 42604 : MemoryContext oldcontext;
1991 : :
1992 : 42604 : rinfo = ec_search_clause_for_ems(root, ec, leftem, rightem, parent_ec);
1993 [ + + ]: 42604 : if (rinfo)
1994 : 34442 : return rinfo;
1995 : :
1996 : : /*
1997 : : * Not there, so build it, in planner context so we can re-use it. (Not
1998 : : * important in normal planning, but definitely so in GEQO.)
1999 : : */
2000 : 8162 : oldcontext = MemoryContextSwitchTo(root->planner_cxt);
2001 : :
2002 : : /*
2003 : : * If either EM is a child, recursively create the corresponding
2004 : : * parent-to-parent clause, so that we can duplicate its rinfo_serial.
2005 : : */
2006 [ + + + + ]: 8162 : if (leftem->em_is_child || rightem->em_is_child)
2007 : : {
2008 [ + + ]: 803 : EquivalenceMember *leftp = leftem->em_parent ? leftem->em_parent : leftem;
2009 [ + + ]: 803 : EquivalenceMember *rightp = rightem->em_parent ? rightem->em_parent : rightem;
2010 : :
2011 : 1606 : parent_rinfo = create_join_clause(root, ec, opno,
2012 : 803 : leftp, rightp,
2013 : 803 : parent_ec);
2014 : 803 : }
2015 : :
2016 : 16324 : rinfo = build_implied_join_equality(root,
2017 : 8162 : opno,
2018 : 8162 : ec->ec_collation,
2019 : 8162 : leftem->em_expr,
2020 : 8162 : rightem->em_expr,
2021 : 16324 : bms_union(leftem->em_relids,
2022 : 8162 : rightem->em_relids),
2023 : 8162 : ec->ec_min_security);
2024 : :
2025 : : /*
2026 : : * If either EM is a child, force the clause's clause_relids to include
2027 : : * the relid(s) of the child rel. In normal cases it would already, but
2028 : : * not if we are considering appendrel child relations with pseudoconstant
2029 : : * translated variables (i.e., UNION ALL sub-selects with constant output
2030 : : * items). We must do this so that join_clause_is_movable_into() will
2031 : : * think that the clause should be evaluated at the correct place.
2032 : : */
2033 [ + + ]: 8162 : if (leftem->em_is_child)
2034 : 1426 : rinfo->clause_relids = bms_add_members(rinfo->clause_relids,
2035 : 713 : leftem->em_relids);
2036 [ + + ]: 8162 : if (rightem->em_is_child)
2037 : 180 : rinfo->clause_relids = bms_add_members(rinfo->clause_relids,
2038 : 90 : rightem->em_relids);
2039 : :
2040 : : /* If it's a child clause, copy the parent's rinfo_serial */
2041 [ + + ]: 8162 : if (parent_rinfo)
2042 : 803 : rinfo->rinfo_serial = parent_rinfo->rinfo_serial;
2043 : :
2044 : : /* Mark the clause as redundant, or not */
2045 : 8162 : rinfo->parent_ec = parent_ec;
2046 : :
2047 : : /*
2048 : : * We know the correct values for left_ec/right_ec, ie this particular EC,
2049 : : * so we can just set them directly instead of forcing another lookup.
2050 : : */
2051 : 8162 : rinfo->left_ec = ec;
2052 : 8162 : rinfo->right_ec = ec;
2053 : :
2054 : : /* Mark it as usable with these EMs */
2055 : 8162 : rinfo->left_em = leftem;
2056 : 8162 : rinfo->right_em = rightem;
2057 : : /* and save it for possible re-use */
2058 : 8162 : ec_add_derived_clause(ec, rinfo);
2059 : :
2060 : 8162 : MemoryContextSwitchTo(oldcontext);
2061 : :
2062 : 8162 : return rinfo;
2063 : 42604 : }
2064 : :
2065 : :
2066 : : /*
2067 : : * reconsider_outer_join_clauses
2068 : : * Re-examine any outer-join clauses that were set aside by
2069 : : * distribute_qual_to_rels(), and see if we can derive any
2070 : : * EquivalenceClasses from them. Then, if they were not made
2071 : : * redundant, push them out into the regular join-clause lists.
2072 : : *
2073 : : * When we have mergejoinable clauses A = B that are outer-join clauses,
2074 : : * we can't blindly combine them with other clauses A = C to deduce B = C,
2075 : : * since in fact the "equality" A = B won't necessarily hold above the
2076 : : * outer join (one of the variables might be NULL instead). Nonetheless
2077 : : * there are cases where we can add qual clauses using transitivity.
2078 : : *
2079 : : * One case that we look for here is an outer-join clause OUTERVAR = INNERVAR
2080 : : * for which there is also an equivalence clause OUTERVAR = CONSTANT.
2081 : : * It is safe and useful to push a clause INNERVAR = CONSTANT into the
2082 : : * evaluation of the inner (nullable) relation, because any inner rows not
2083 : : * meeting this condition will not contribute to the outer-join result anyway.
2084 : : * (Any outer rows they could join to will be eliminated by the pushed-down
2085 : : * equivalence clause.)
2086 : : *
2087 : : * Note that the above rule does not work for full outer joins; nor is it
2088 : : * very interesting to consider cases where the generated equivalence clause
2089 : : * would involve relations outside the outer join, since such clauses couldn't
2090 : : * be pushed into the inner side's scan anyway. So the restriction to
2091 : : * outervar = pseudoconstant is not really giving up anything.
2092 : : *
2093 : : * For full-join cases, we can only do something useful if it's a FULL JOIN
2094 : : * USING and a merged column has an equivalence MERGEDVAR = CONSTANT.
2095 : : * By the time it gets here, the merged column will look like
2096 : : * COALESCE(LEFTVAR, RIGHTVAR)
2097 : : * and we will have a full-join clause LEFTVAR = RIGHTVAR that we can match
2098 : : * the COALESCE expression to. In this situation we can push LEFTVAR = CONSTANT
2099 : : * and RIGHTVAR = CONSTANT into the input relations, since any rows not
2100 : : * meeting these conditions cannot contribute to the join result.
2101 : : *
2102 : : * Again, there isn't any traction to be gained by trying to deal with
2103 : : * clauses comparing a mergedvar to a non-pseudoconstant. So we can make
2104 : : * use of the EquivalenceClasses to search for matching variables that were
2105 : : * equivalenced to constants. The interesting outer-join clauses were
2106 : : * accumulated for us by distribute_qual_to_rels.
2107 : : *
2108 : : * When we find one of these cases, we implement the changes we want by
2109 : : * generating a new equivalence clause INNERVAR = CONSTANT (or LEFTVAR, etc)
2110 : : * and pushing it into the EquivalenceClass structures. This is because we
2111 : : * may already know that INNERVAR is equivalenced to some other var(s), and
2112 : : * we'd like the constant to propagate to them too. Note that it would be
2113 : : * unsafe to merge any existing EC for INNERVAR with the OUTERVAR's EC ---
2114 : : * that could result in propagating constant restrictions from
2115 : : * INNERVAR to OUTERVAR, which would be very wrong.
2116 : : *
2117 : : * It's possible that the INNERVAR is also an OUTERVAR for some other
2118 : : * outer-join clause, in which case the process can be repeated. So we repeat
2119 : : * looping over the lists of clauses until no further deductions can be made.
2120 : : * Whenever we do make a deduction, we remove the generating clause from the
2121 : : * lists, since we don't want to make the same deduction twice.
2122 : : *
2123 : : * If we don't find any match for a set-aside outer join clause, we must
2124 : : * throw it back into the regular joinclause processing by passing it to
2125 : : * distribute_restrictinfo_to_rels(). If we do generate a derived clause,
2126 : : * however, the outer-join clause is redundant. We must still put some
2127 : : * clause into the regular processing, because otherwise the join will be
2128 : : * seen as a clauseless join and avoided during join order searching.
2129 : : * We handle this by generating a constant-TRUE clause that is marked with
2130 : : * the same required_relids etc as the removed outer-join clause, thus
2131 : : * making it a join clause between the correct relations.
2132 : : */
2133 : : void
2134 : 33901 : reconsider_outer_join_clauses(PlannerInfo *root)
2135 : : {
2136 : 33901 : bool found;
2137 : 33901 : ListCell *cell;
2138 : :
2139 : : /* Outer loop repeats until we find no more deductions */
2140 : 33901 : do
2141 : : {
2142 : 34104 : found = false;
2143 : :
2144 : : /* Process the LEFT JOIN clauses */
2145 [ + + + + : 36801 : foreach(cell, root->left_join_clauses)
+ + ]
2146 : : {
2147 : 2697 : OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2148 : :
2149 [ + + ]: 2697 : if (reconsider_outer_join_clause(root, ojcinfo, true))
2150 : : {
2151 : 36 : RestrictInfo *rinfo = ojcinfo->rinfo;
2152 : :
2153 : 36 : found = true;
2154 : : /* remove it from the list */
2155 : 36 : root->left_join_clauses =
2156 : 36 : foreach_delete_current(root->left_join_clauses, cell);
2157 : : /* throw back a dummy replacement clause (see notes above) */
2158 : 72 : rinfo = make_restrictinfo(root,
2159 : 36 : (Expr *) makeBoolConst(true, false),
2160 : 36 : rinfo->is_pushed_down,
2161 : 36 : rinfo->has_clone,
2162 : 36 : rinfo->is_clone,
2163 : : false, /* pseudoconstant */
2164 : : 0, /* security_level */
2165 : 36 : rinfo->required_relids,
2166 : 36 : rinfo->incompatible_relids,
2167 : 36 : rinfo->outer_relids);
2168 : 36 : distribute_restrictinfo_to_rels(root, rinfo);
2169 : 36 : }
2170 : 2697 : }
2171 : :
2172 : : /* Process the RIGHT JOIN clauses */
2173 [ + + + + : 36260 : foreach(cell, root->right_join_clauses)
+ + ]
2174 : : {
2175 : 2156 : OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2176 : :
2177 [ + + ]: 2156 : if (reconsider_outer_join_clause(root, ojcinfo, false))
2178 : : {
2179 : 168 : RestrictInfo *rinfo = ojcinfo->rinfo;
2180 : :
2181 : 168 : found = true;
2182 : : /* remove it from the list */
2183 : 168 : root->right_join_clauses =
2184 : 168 : foreach_delete_current(root->right_join_clauses, cell);
2185 : : /* throw back a dummy replacement clause (see notes above) */
2186 : 336 : rinfo = make_restrictinfo(root,
2187 : 168 : (Expr *) makeBoolConst(true, false),
2188 : 168 : rinfo->is_pushed_down,
2189 : 168 : rinfo->has_clone,
2190 : 168 : rinfo->is_clone,
2191 : : false, /* pseudoconstant */
2192 : : 0, /* security_level */
2193 : 168 : rinfo->required_relids,
2194 : 168 : rinfo->incompatible_relids,
2195 : 168 : rinfo->outer_relids);
2196 : 168 : distribute_restrictinfo_to_rels(root, rinfo);
2197 : 168 : }
2198 : 2156 : }
2199 : :
2200 : : /* Process the FULL JOIN clauses */
2201 [ + + + + : 34278 : foreach(cell, root->full_join_clauses)
+ + ]
2202 : : {
2203 : 174 : OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2204 : :
2205 [ + + ]: 174 : if (reconsider_full_join_clause(root, ojcinfo))
2206 : : {
2207 : 1 : RestrictInfo *rinfo = ojcinfo->rinfo;
2208 : :
2209 : 1 : found = true;
2210 : : /* remove it from the list */
2211 : 1 : root->full_join_clauses =
2212 : 1 : foreach_delete_current(root->full_join_clauses, cell);
2213 : : /* throw back a dummy replacement clause (see notes above) */
2214 : 2 : rinfo = make_restrictinfo(root,
2215 : 1 : (Expr *) makeBoolConst(true, false),
2216 : 1 : rinfo->is_pushed_down,
2217 : 1 : rinfo->has_clone,
2218 : 1 : rinfo->is_clone,
2219 : : false, /* pseudoconstant */
2220 : : 0, /* security_level */
2221 : 1 : rinfo->required_relids,
2222 : 1 : rinfo->incompatible_relids,
2223 : 1 : rinfo->outer_relids);
2224 : 1 : distribute_restrictinfo_to_rels(root, rinfo);
2225 : 1 : }
2226 : 174 : }
2227 [ + + ]: 34104 : } while (found);
2228 : :
2229 : : /* Now, any remaining clauses have to be thrown back */
2230 [ + + + + : 36558 : foreach(cell, root->left_join_clauses)
+ + ]
2231 : : {
2232 : 2657 : OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2233 : :
2234 : 2657 : distribute_restrictinfo_to_rels(root, ojcinfo->rinfo);
2235 : 2657 : }
2236 [ + + + + : 35713 : foreach(cell, root->right_join_clauses)
+ + ]
2237 : : {
2238 : 1812 : OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2239 : :
2240 : 1812 : distribute_restrictinfo_to_rels(root, ojcinfo->rinfo);
2241 : 1812 : }
2242 [ + + + + : 34074 : foreach(cell, root->full_join_clauses)
+ + ]
2243 : : {
2244 : 173 : OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2245 : :
2246 : 173 : distribute_restrictinfo_to_rels(root, ojcinfo->rinfo);
2247 : 173 : }
2248 : 33901 : }
2249 : :
2250 : : /*
2251 : : * reconsider_outer_join_clauses for a single LEFT/RIGHT JOIN clause
2252 : : *
2253 : : * Returns true if we were able to propagate a constant through the clause.
2254 : : */
2255 : : static bool
2256 : 4853 : reconsider_outer_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo,
2257 : : bool outer_on_left)
2258 : : {
2259 : 4853 : RestrictInfo *rinfo = ojcinfo->rinfo;
2260 : 4853 : SpecialJoinInfo *sjinfo = ojcinfo->sjinfo;
2261 : 4853 : Expr *outervar,
2262 : : *innervar;
2263 : 4853 : Oid opno,
2264 : : collation,
2265 : : left_type,
2266 : : right_type,
2267 : : inner_datatype;
2268 : 4853 : Relids inner_relids;
2269 : 4853 : ListCell *lc1;
2270 : :
2271 [ + - ]: 4853 : Assert(is_opclause(rinfo->clause));
2272 : 4853 : opno = ((OpExpr *) rinfo->clause)->opno;
2273 : 4853 : collation = ((OpExpr *) rinfo->clause)->inputcollid;
2274 : :
2275 : : /* Extract needed info from the clause */
2276 : 4853 : op_input_types(opno, &left_type, &right_type);
2277 [ + + ]: 4853 : if (outer_on_left)
2278 : : {
2279 : 2697 : outervar = (Expr *) get_leftop(rinfo->clause);
2280 : 2697 : innervar = (Expr *) get_rightop(rinfo->clause);
2281 : 2697 : inner_datatype = right_type;
2282 : 2697 : inner_relids = rinfo->right_relids;
2283 : 2697 : }
2284 : : else
2285 : : {
2286 : 2156 : outervar = (Expr *) get_rightop(rinfo->clause);
2287 : 2156 : innervar = (Expr *) get_leftop(rinfo->clause);
2288 : 2156 : inner_datatype = left_type;
2289 : 2156 : inner_relids = rinfo->left_relids;
2290 : : }
2291 : :
2292 : : /* Scan EquivalenceClasses for a match to outervar */
2293 [ + - + + : 25508 : foreach(lc1, root->eq_classes)
+ + + + ]
2294 : : {
2295 : 20655 : EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
2296 : 20655 : bool match;
2297 : 20655 : ListCell *lc2;
2298 : :
2299 : : /* We don't expect any children yet */
2300 [ + - ]: 20655 : Assert(cur_ec->ec_childmembers == NULL);
2301 : :
2302 : : /* Ignore EC unless it contains pseudoconstants */
2303 [ + + ]: 20655 : if (!cur_ec->ec_has_const)
2304 : 16845 : continue;
2305 : : /* Never match to a volatile EC */
2306 [ - + ]: 3810 : if (cur_ec->ec_has_volatile)
2307 : 0 : continue;
2308 : : /* It has to match the outer-join clause as to semantics, too */
2309 [ + + ]: 3810 : if (collation != cur_ec->ec_collation)
2310 : 294 : continue;
2311 [ + + ]: 3516 : if (!equal(rinfo->mergeopfamilies, cur_ec->ec_opfamilies))
2312 : 418 : continue;
2313 : : /* Does it contain a match to outervar? */
2314 : 3098 : match = false;
2315 [ + - + + : 9831 : foreach(lc2, cur_ec->ec_members)
+ + ]
2316 : : {
2317 : 6733 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
2318 : :
2319 : : /* Child members should not exist in ec_members */
2320 [ - + ]: 6733 : Assert(!cur_em->em_is_child);
2321 [ + + ]: 6733 : if (equal(outervar, cur_em->em_expr))
2322 : : {
2323 : 204 : match = true;
2324 : 204 : break;
2325 : : }
2326 [ + + ]: 6733 : }
2327 [ + + ]: 3098 : if (!match)
2328 : 2894 : continue; /* no match, so ignore this EC */
2329 : :
2330 : : /*
2331 : : * Yes it does! Try to generate a clause INNERVAR = CONSTANT for each
2332 : : * CONSTANT in the EC. Note that we must succeed with at least one
2333 : : * constant before we can decide to throw away the outer-join clause.
2334 : : */
2335 : 204 : match = false;
2336 [ + - + + : 789 : foreach(lc2, cur_ec->ec_members)
+ + ]
2337 : : {
2338 : 585 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
2339 : 585 : Oid eq_op;
2340 : 585 : RestrictInfo *newrinfo;
2341 : 585 : JoinDomain *jdomain;
2342 : :
2343 [ + + ]: 585 : if (!cur_em->em_is_const)
2344 : 374 : continue; /* ignore non-const members */
2345 : 422 : eq_op = select_equality_operator(cur_ec,
2346 : 211 : inner_datatype,
2347 : 211 : cur_em->em_datatype);
2348 [ + - ]: 211 : if (!OidIsValid(eq_op))
2349 : 0 : continue; /* can't generate equality */
2350 : 422 : newrinfo = build_implied_join_equality(root,
2351 : 211 : eq_op,
2352 : 211 : cur_ec->ec_collation,
2353 : 211 : innervar,
2354 : 211 : cur_em->em_expr,
2355 : 211 : bms_copy(inner_relids),
2356 : 211 : cur_ec->ec_min_security);
2357 : : /* This equality holds within the OJ's child JoinDomain */
2358 : 211 : jdomain = find_join_domain(root, sjinfo->syn_righthand);
2359 [ - + ]: 211 : if (process_equivalence(root, &newrinfo, jdomain))
2360 : 211 : match = true;
2361 [ - + + ]: 585 : }
2362 : :
2363 : : /*
2364 : : * If we were able to equate INNERVAR to any constant, report success.
2365 : : * Otherwise, fall out of the search loop, since we know the OUTERVAR
2366 : : * appears in at most one EC.
2367 : : */
2368 [ + - ]: 204 : if (match)
2369 : 204 : return true;
2370 : : else
2371 : 0 : break;
2372 [ + + ]: 20655 : }
2373 : :
2374 : 4649 : return false; /* failed to make any deduction */
2375 : 4853 : }
2376 : :
2377 : : /*
2378 : : * reconsider_outer_join_clauses for a single FULL JOIN clause
2379 : : *
2380 : : * Returns true if we were able to propagate a constant through the clause.
2381 : : */
2382 : : static bool
2383 : 174 : reconsider_full_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo)
2384 : : {
2385 : 174 : RestrictInfo *rinfo = ojcinfo->rinfo;
2386 : 174 : SpecialJoinInfo *sjinfo = ojcinfo->sjinfo;
2387 : 174 : Relids fjrelids = bms_make_singleton(sjinfo->ojrelid);
2388 : 174 : Expr *leftvar;
2389 : 174 : Expr *rightvar;
2390 : 174 : Oid opno,
2391 : : collation,
2392 : : left_type,
2393 : : right_type;
2394 : 174 : Relids left_relids,
2395 : : right_relids;
2396 : 174 : ListCell *lc1;
2397 : :
2398 : : /* Extract needed info from the clause */
2399 [ + - ]: 174 : Assert(is_opclause(rinfo->clause));
2400 : 174 : opno = ((OpExpr *) rinfo->clause)->opno;
2401 : 174 : collation = ((OpExpr *) rinfo->clause)->inputcollid;
2402 : 174 : op_input_types(opno, &left_type, &right_type);
2403 : 174 : leftvar = (Expr *) get_leftop(rinfo->clause);
2404 : 174 : rightvar = (Expr *) get_rightop(rinfo->clause);
2405 : 174 : left_relids = rinfo->left_relids;
2406 : 174 : right_relids = rinfo->right_relids;
2407 : :
2408 [ + - + + : 904 : foreach(lc1, root->eq_classes)
+ + + + ]
2409 : : {
2410 : 730 : EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
2411 : 730 : EquivalenceMember *coal_em = NULL;
2412 : 730 : bool match;
2413 : 730 : bool matchleft;
2414 : 730 : bool matchright;
2415 : 730 : ListCell *lc2;
2416 : 730 : int coal_idx = -1;
2417 : :
2418 : : /* We don't expect any children yet */
2419 [ + - ]: 730 : Assert(cur_ec->ec_childmembers == NULL);
2420 : :
2421 : : /* Ignore EC unless it contains pseudoconstants */
2422 [ + + ]: 730 : if (!cur_ec->ec_has_const)
2423 : 684 : continue;
2424 : : /* Never match to a volatile EC */
2425 [ - + ]: 46 : if (cur_ec->ec_has_volatile)
2426 : 0 : continue;
2427 : : /* It has to match the outer-join clause as to semantics, too */
2428 [ + + ]: 46 : if (collation != cur_ec->ec_collation)
2429 : 6 : continue;
2430 [ + - ]: 40 : if (!equal(rinfo->mergeopfamilies, cur_ec->ec_opfamilies))
2431 : 0 : continue;
2432 : :
2433 : : /*
2434 : : * Does it contain a COALESCE(leftvar, rightvar) construct?
2435 : : *
2436 : : * We can assume the COALESCE() inputs are in the same order as the
2437 : : * join clause, since both were automatically generated in the cases
2438 : : * we care about.
2439 : : *
2440 : : * XXX currently this may fail to match in cross-type cases because
2441 : : * the COALESCE will contain typecast operations while the join clause
2442 : : * may not (if there is a cross-type mergejoin operator available for
2443 : : * the two column types). Is it OK to strip implicit coercions from
2444 : : * the COALESCE arguments?
2445 : : */
2446 : 40 : match = false;
2447 [ + - + + : 118 : foreach(lc2, cur_ec->ec_members)
+ + ]
2448 : : {
2449 : 78 : coal_em = (EquivalenceMember *) lfirst(lc2);
2450 : :
2451 : : /* Child members should not exist in ec_members */
2452 [ - + ]: 78 : Assert(!coal_em->em_is_child);
2453 [ + + ]: 78 : if (IsA(coal_em->em_expr, CoalesceExpr))
2454 : : {
2455 : 3 : CoalesceExpr *cexpr = (CoalesceExpr *) coal_em->em_expr;
2456 : 3 : Node *cfirst;
2457 : 3 : Node *csecond;
2458 : :
2459 [ - + ]: 3 : if (list_length(cexpr->args) != 2)
2460 : 0 : continue;
2461 : 3 : cfirst = (Node *) linitial(cexpr->args);
2462 : 3 : csecond = (Node *) lsecond(cexpr->args);
2463 : :
2464 : : /*
2465 : : * The COALESCE arguments will be marked as possibly nulled by
2466 : : * the full join, while we wish to generate clauses that apply
2467 : : * to the join's inputs. So we must strip the join from the
2468 : : * nullingrels fields of cfirst/csecond before comparing them
2469 : : * to leftvar/rightvar. (Perhaps with a less hokey
2470 : : * representation for FULL JOIN USING output columns, this
2471 : : * wouldn't be needed?)
2472 : : */
2473 : 3 : cfirst = remove_nulling_relids(cfirst, fjrelids, NULL);
2474 : 3 : csecond = remove_nulling_relids(csecond, fjrelids, NULL);
2475 : :
2476 [ + + - + ]: 3 : if (equal(leftvar, cfirst) && equal(rightvar, csecond))
2477 : : {
2478 : 1 : coal_idx = foreach_current_index(lc2);
2479 : 1 : match = true;
2480 : 1 : break;
2481 : : }
2482 [ - + + ]: 3 : }
2483 : 77 : }
2484 [ + + ]: 40 : if (!match)
2485 : 39 : continue; /* no match, so ignore this EC */
2486 : :
2487 : : /*
2488 : : * Yes it does! Try to generate clauses LEFTVAR = CONSTANT and
2489 : : * RIGHTVAR = CONSTANT for each CONSTANT in the EC. Note that we must
2490 : : * succeed with at least one constant for each var before we can
2491 : : * decide to throw away the outer-join clause.
2492 : : */
2493 : 1 : matchleft = matchright = false;
2494 [ + - + + : 3 : foreach(lc2, cur_ec->ec_members)
+ + ]
2495 : : {
2496 : 2 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
2497 : 2 : Oid eq_op;
2498 : 2 : RestrictInfo *newrinfo;
2499 : 2 : JoinDomain *jdomain;
2500 : :
2501 [ + + ]: 2 : if (!cur_em->em_is_const)
2502 : 1 : continue; /* ignore non-const members */
2503 : 2 : eq_op = select_equality_operator(cur_ec,
2504 : 1 : left_type,
2505 : 1 : cur_em->em_datatype);
2506 [ + - ]: 1 : if (OidIsValid(eq_op))
2507 : : {
2508 : 2 : newrinfo = build_implied_join_equality(root,
2509 : 1 : eq_op,
2510 : 1 : cur_ec->ec_collation,
2511 : 1 : leftvar,
2512 : 1 : cur_em->em_expr,
2513 : 1 : bms_copy(left_relids),
2514 : 1 : cur_ec->ec_min_security);
2515 : : /* This equality holds within the lefthand child JoinDomain */
2516 : 1 : jdomain = find_join_domain(root, sjinfo->syn_lefthand);
2517 [ - + ]: 1 : if (process_equivalence(root, &newrinfo, jdomain))
2518 : 1 : matchleft = true;
2519 : 1 : }
2520 : 2 : eq_op = select_equality_operator(cur_ec,
2521 : 1 : right_type,
2522 : 1 : cur_em->em_datatype);
2523 [ + - ]: 1 : if (OidIsValid(eq_op))
2524 : : {
2525 : 2 : newrinfo = build_implied_join_equality(root,
2526 : 1 : eq_op,
2527 : 1 : cur_ec->ec_collation,
2528 : 1 : rightvar,
2529 : 1 : cur_em->em_expr,
2530 : 1 : bms_copy(right_relids),
2531 : 1 : cur_ec->ec_min_security);
2532 : : /* This equality holds within the righthand child JoinDomain */
2533 : 1 : jdomain = find_join_domain(root, sjinfo->syn_righthand);
2534 [ - + ]: 1 : if (process_equivalence(root, &newrinfo, jdomain))
2535 : 1 : matchright = true;
2536 : 1 : }
2537 [ - + + ]: 2 : }
2538 : :
2539 : : /*
2540 : : * If we were able to equate both vars to constants, we're done, and
2541 : : * we can throw away the full-join clause as redundant. Moreover, we
2542 : : * can remove the COALESCE entry from the EC, since the added
2543 : : * restrictions ensure it will always have the expected value. (We
2544 : : * don't bother trying to update ec_relids or ec_sources.)
2545 : : */
2546 [ + - - + ]: 1 : if (matchleft && matchright)
2547 : : {
2548 : 1 : cur_ec->ec_members = list_delete_nth_cell(cur_ec->ec_members, coal_idx);
2549 : 1 : return true;
2550 : : }
2551 : :
2552 : : /*
2553 : : * Otherwise, fall out of the search loop, since we know the COALESCE
2554 : : * appears in at most one EC (XXX might stop being true if we allow
2555 : : * stripping of coercions above?)
2556 : : */
2557 : 0 : break;
2558 [ + + ]: 730 : }
2559 : :
2560 : 173 : return false; /* failed to make any deduction */
2561 : 174 : }
2562 : :
2563 : : /*
2564 : : * rebuild_eclass_attr_needed
2565 : : * Put back attr_needed bits for Vars/PHVs needed for join eclasses.
2566 : : *
2567 : : * This is used to rebuild attr_needed/ph_needed sets after removal of a
2568 : : * useless outer join. It should match what
2569 : : * generate_base_implied_equalities_no_const did, except that we call
2570 : : * add_vars_to_attr_needed not add_vars_to_targetlist.
2571 : : */
2572 : : void
2573 : 1193 : rebuild_eclass_attr_needed(PlannerInfo *root)
2574 : : {
2575 : 1193 : ListCell *lc;
2576 : :
2577 [ + - + + : 6911 : foreach(lc, root->eq_classes)
+ + ]
2578 : : {
2579 : 5718 : EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc);
2580 : :
2581 : : /*
2582 : : * We don't expect any EC child members to exist at this point. Ensure
2583 : : * that's the case, otherwise, we might be getting asked to do
2584 : : * something this function hasn't been coded for.
2585 : : */
2586 [ + - ]: 5718 : Assert(ec->ec_childmembers == NULL);
2587 : :
2588 : : /* Need do anything only for a multi-member, no-const EC. */
2589 [ + + + + ]: 5718 : if (list_length(ec->ec_members) > 1 && !ec->ec_has_const)
2590 : : {
2591 : 388 : ListCell *lc2;
2592 : :
2593 [ + - + + : 1171 : foreach(lc2, ec->ec_members)
+ + ]
2594 : : {
2595 : 783 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
2596 : 783 : List *vars = pull_var_clause((Node *) cur_em->em_expr,
2597 : : PVC_RECURSE_AGGREGATES |
2598 : : PVC_RECURSE_WINDOWFUNCS |
2599 : : PVC_INCLUDE_PLACEHOLDERS);
2600 : :
2601 : 783 : add_vars_to_attr_needed(root, vars, ec->ec_relids);
2602 : 783 : list_free(vars);
2603 : 783 : }
2604 : 388 : }
2605 : 5718 : }
2606 : 1193 : }
2607 : :
2608 : : /*
2609 : : * find_join_domain
2610 : : * Find the highest JoinDomain enclosed within the given relid set.
2611 : : *
2612 : : * (We could avoid this search at the cost of complicating APIs elsewhere,
2613 : : * which doesn't seem worth it.)
2614 : : */
2615 : : static JoinDomain *
2616 : 213 : find_join_domain(PlannerInfo *root, Relids relids)
2617 : : {
2618 : 213 : ListCell *lc;
2619 : :
2620 [ + - - + : 655 : foreach(lc, root->join_domains)
+ - + - ]
2621 : : {
2622 : 442 : JoinDomain *jdomain = (JoinDomain *) lfirst(lc);
2623 : :
2624 [ + + ]: 442 : if (bms_is_subset(jdomain->jd_relids, relids))
2625 : 213 : return jdomain;
2626 [ + + ]: 442 : }
2627 [ # # # # ]: 0 : elog(ERROR, "failed to find appropriate JoinDomain");
2628 : 0 : return NULL; /* keep compiler quiet */
2629 : 213 : }
2630 : :
2631 : :
2632 : : /*
2633 : : * exprs_known_equal
2634 : : * Detect whether two expressions are known equal due to equivalence
2635 : : * relationships.
2636 : : *
2637 : : * If opfamily is given, the expressions must be known equal per the semantics
2638 : : * of that opfamily (note it has to be a btree opfamily, since those are the
2639 : : * only opfamilies equivclass.c deals with). If opfamily is InvalidOid, we'll
2640 : : * return true if they're equal according to any opfamily, which is fuzzy but
2641 : : * OK for estimation purposes.
2642 : : *
2643 : : * Note: does not bother to check for "equal(item1, item2)"; caller must
2644 : : * check that case if it's possible to pass identical items.
2645 : : */
2646 : : bool
2647 : 771 : exprs_known_equal(PlannerInfo *root, Node *item1, Node *item2, Oid opfamily)
2648 : : {
2649 : 771 : ListCell *lc1;
2650 : :
2651 [ + + + + : 10430 : foreach(lc1, root->eq_classes)
+ + + + ]
2652 : : {
2653 : 9659 : EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc1);
2654 : 9659 : bool item1member = false;
2655 : 9659 : bool item2member = false;
2656 : 9659 : ListCell *lc2;
2657 : :
2658 : : /* Never match to a volatile EC */
2659 [ - + ]: 9659 : if (ec->ec_has_volatile)
2660 : 0 : continue;
2661 : :
2662 : : /*
2663 : : * It's okay to consider ec_broken ECs here. Brokenness just means we
2664 : : * couldn't derive all the implied clauses we'd have liked to; it does
2665 : : * not invalidate our knowledge that the members are equal.
2666 : : */
2667 : :
2668 : : /* Ignore if this EC doesn't use specified opfamily */
2669 [ + + + + ]: 9659 : if (OidIsValid(opfamily) &&
2670 : 110 : !list_member_oid(ec->ec_opfamilies, opfamily))
2671 : 38 : continue;
2672 : :
2673 : : /* Ignore children here */
2674 [ + - + + : 21136 : foreach(lc2, ec->ec_members)
+ + + + ]
2675 : : {
2676 : 11515 : EquivalenceMember *em = (EquivalenceMember *) lfirst(lc2);
2677 : :
2678 : : /* Child members should not exist in ec_members */
2679 [ + - ]: 11515 : Assert(!em->em_is_child);
2680 [ + + ]: 11515 : if (equal(item1, em->em_expr))
2681 : 425 : item1member = true;
2682 [ + + ]: 11090 : else if (equal(item2, em->em_expr))
2683 : 521 : item2member = true;
2684 : : /* Exit as soon as equality is proven */
2685 [ + + + + ]: 11515 : if (item1member && item2member)
2686 : 61 : return true;
2687 [ + + ]: 11515 : }
2688 [ + + + ]: 9659 : }
2689 : 710 : return false;
2690 : 771 : }
2691 : :
2692 : :
2693 : : /*
2694 : : * match_eclasses_to_foreign_key_col
2695 : : * See whether a foreign key column match is proven by any eclass.
2696 : : *
2697 : : * If the referenced and referencing Vars of the fkey's colno'th column are
2698 : : * known equal due to any eclass, return that eclass; otherwise return NULL.
2699 : : * (In principle there might be more than one matching eclass if multiple
2700 : : * collations are involved, but since collation doesn't matter for equality,
2701 : : * we ignore that fine point here.) This is much like exprs_known_equal,
2702 : : * except for the format of the input.
2703 : : *
2704 : : * On success, we also set fkinfo->eclass[colno] to the matching eclass,
2705 : : * and set fkinfo->fk_eclass_member[colno] to the eclass member for the
2706 : : * referencing Var.
2707 : : */
2708 : : EquivalenceClass *
2709 : 369 : match_eclasses_to_foreign_key_col(PlannerInfo *root,
2710 : : ForeignKeyOptInfo *fkinfo,
2711 : : int colno)
2712 : : {
2713 : 369 : Index var1varno = fkinfo->con_relid;
2714 : 369 : AttrNumber var1attno = fkinfo->conkey[colno];
2715 : 369 : Index var2varno = fkinfo->ref_relid;
2716 : 369 : AttrNumber var2attno = fkinfo->confkey[colno];
2717 : 369 : Oid eqop = fkinfo->conpfeqop[colno];
2718 : 369 : RelOptInfo *rel1 = root->simple_rel_array[var1varno];
2719 : 369 : RelOptInfo *rel2 = root->simple_rel_array[var2varno];
2720 : 369 : List *opfamilies = NIL; /* compute only if needed */
2721 : 369 : Bitmapset *matching_ecs;
2722 : 369 : int i;
2723 : :
2724 : : /* Consider only eclasses mentioning both relations */
2725 [ + - ]: 369 : Assert(root->ec_merging_done);
2726 [ - + # # ]: 369 : Assert(IS_SIMPLE_REL(rel1));
2727 [ - + # # ]: 369 : Assert(IS_SIMPLE_REL(rel2));
2728 : 738 : matching_ecs = bms_intersect(rel1->eclass_indexes,
2729 : 369 : rel2->eclass_indexes);
2730 : :
2731 : 369 : i = -1;
2732 [ + + ]: 385 : while ((i = bms_next_member(matching_ecs, i)) >= 0)
2733 : : {
2734 : 222 : EquivalenceClass *ec = (EquivalenceClass *) list_nth(root->eq_classes,
2735 : 111 : i);
2736 : 111 : EquivalenceMember *item1_em = NULL;
2737 : 111 : EquivalenceMember *item2_em = NULL;
2738 : 111 : ListCell *lc2;
2739 : :
2740 : : /* Never match to a volatile EC */
2741 [ - + ]: 111 : if (ec->ec_has_volatile)
2742 : 0 : continue;
2743 : :
2744 : : /*
2745 : : * It's okay to consider "broken" ECs here, see exprs_known_equal.
2746 : : * Ignore children here.
2747 : : */
2748 [ + - + + : 350 : foreach(lc2, ec->ec_members)
+ + + + ]
2749 : : {
2750 : 239 : EquivalenceMember *em = (EquivalenceMember *) lfirst(lc2);
2751 : 239 : Var *var;
2752 : :
2753 : : /* Child members should not exist in ec_members */
2754 [ + - ]: 239 : Assert(!em->em_is_child);
2755 : :
2756 : : /* EM must be a Var, possibly with RelabelType */
2757 : 239 : var = (Var *) em->em_expr;
2758 [ - + - + ]: 239 : while (var && IsA(var, RelabelType))
2759 : 0 : var = (Var *) ((RelabelType *) var)->arg;
2760 [ + - + + ]: 239 : if (!(var && IsA(var, Var)))
2761 : 1 : continue;
2762 : :
2763 : : /* Match? */
2764 [ + + + + ]: 238 : if (var->varno == var1varno && var->varattno == var1attno)
2765 : 95 : item1_em = em;
2766 [ + + + + ]: 143 : else if (var->varno == var2varno && var->varattno == var2attno)
2767 : 95 : item2_em = em;
2768 : :
2769 : : /* Have we found both PK and FK column in this EC? */
2770 [ + + + + ]: 238 : if (item1_em && item2_em)
2771 : : {
2772 : : /*
2773 : : * Succeed if eqop matches EC's opfamilies. We could test
2774 : : * this before scanning the members, but it's probably cheaper
2775 : : * to test for member matches first.
2776 : : */
2777 [ - + ]: 95 : if (opfamilies == NIL) /* compute if we didn't already */
2778 : 95 : opfamilies = get_mergejoin_opfamilies(eqop);
2779 [ + - ]: 95 : if (equal(opfamilies, ec->ec_opfamilies))
2780 : : {
2781 : 95 : fkinfo->eclass[colno] = ec;
2782 : 95 : fkinfo->fk_eclass_member[colno] = item2_em;
2783 : 95 : return ec;
2784 : : }
2785 : : /* Otherwise, done with this EC, move on to the next */
2786 : 0 : break;
2787 : : }
2788 [ + + + ]: 239 : }
2789 [ - + + ]: 111 : }
2790 : 274 : return NULL;
2791 : 369 : }
2792 : :
2793 : : /*
2794 : : * find_derived_clause_for_ec_member
2795 : : * Search for a previously-derived clause mentioning the given EM.
2796 : : *
2797 : : * The eclass should be an ec_has_const EC, of which the EM is a non-const
2798 : : * member. This should ensure there is just one derived clause mentioning
2799 : : * the EM (and equating it to a constant).
2800 : : * Returns NULL if no such clause can be found.
2801 : : */
2802 : : RestrictInfo *
2803 : 1 : find_derived_clause_for_ec_member(PlannerInfo *root,
2804 : : EquivalenceClass *ec,
2805 : : EquivalenceMember *em)
2806 : : {
2807 [ + - ]: 1 : Assert(ec->ec_has_const);
2808 [ + - ]: 1 : Assert(!em->em_is_const);
2809 : :
2810 : 1 : return ec_search_derived_clause_for_ems(root, ec, em, NULL, NULL);
2811 : : }
2812 : :
2813 : :
2814 : : /*
2815 : : * add_child_rel_equivalences
2816 : : * Search for EC members that reference the root parent of child_rel, and
2817 : : * add transformed members referencing the child_rel.
2818 : : *
2819 : : * Note that this function won't be called at all unless we have at least some
2820 : : * reason to believe that the EC members it generates will be useful.
2821 : : *
2822 : : * parent_rel and child_rel could be derived from appinfo, but since the
2823 : : * caller has already computed them, we might as well just pass them in.
2824 : : *
2825 : : * The passed-in AppendRelInfo is not used when the parent_rel is not a
2826 : : * top-level baserel, since it shows the mapping from the parent_rel but
2827 : : * we need to translate EC expressions that refer to the top-level parent.
2828 : : * Using it is faster than using adjust_appendrel_attrs_multilevel(), though,
2829 : : * so we prefer it when we can.
2830 : : */
2831 : : void
2832 : 4921 : add_child_rel_equivalences(PlannerInfo *root,
2833 : : AppendRelInfo *appinfo,
2834 : : RelOptInfo *parent_rel,
2835 : : RelOptInfo *child_rel)
2836 : : {
2837 : 4921 : Relids top_parent_relids = child_rel->top_parent_relids;
2838 : 4921 : Relids child_relids = child_rel->relids;
2839 : 4921 : int i;
2840 : :
2841 : : /*
2842 : : * EC merging should be complete already, so we can use the parent rel's
2843 : : * eclass_indexes to avoid searching all of root->eq_classes.
2844 : : */
2845 [ + - ]: 4921 : Assert(root->ec_merging_done);
2846 [ + + + - ]: 4921 : Assert(IS_SIMPLE_REL(parent_rel));
2847 : :
2848 : 4921 : i = -1;
2849 [ + + ]: 13574 : while ((i = bms_next_member(parent_rel->eclass_indexes, i)) >= 0)
2850 : : {
2851 : 8653 : EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i);
2852 : :
2853 : : /*
2854 : : * If this EC contains a volatile expression, then generating child
2855 : : * EMs would be downright dangerous, so skip it. We rely on a
2856 : : * volatile EC having only one EM.
2857 : : */
2858 [ - + ]: 8653 : if (cur_ec->ec_has_volatile)
2859 : 0 : continue;
2860 : :
2861 : : /* Sanity check eclass_indexes only contain ECs for parent_rel */
2862 [ + - ]: 8653 : Assert(bms_is_subset(top_parent_relids, cur_ec->ec_relids));
2863 : :
2864 [ + + + - : 30404 : foreach_node(EquivalenceMember, cur_em, cur_ec->ec_members)
+ + + + ]
2865 : : {
2866 [ + + ]: 13098 : if (cur_em->em_is_const)
2867 : 592 : continue; /* ignore consts here */
2868 : :
2869 : : /* Child members should not exist in ec_members */
2870 [ - + ]: 12506 : Assert(!cur_em->em_is_child);
2871 : :
2872 : : /*
2873 : : * Consider only members that reference and can be computed at
2874 : : * child's topmost parent rel. In particular we want to exclude
2875 : : * parent-rel Vars that have nonempty varnullingrels. Translating
2876 : : * those might fail, if the transformed expression wouldn't be a
2877 : : * simple Var; and in any case it wouldn't produce a member that
2878 : : * has any use in creating plans for the child rel.
2879 : : */
2880 [ + + - + ]: 12506 : if (bms_is_subset(cur_em->em_relids, top_parent_relids) &&
2881 : 8282 : !bms_is_empty(cur_em->em_relids))
2882 : : {
2883 : : /* OK, generate transformed child version */
2884 : 8282 : Expr *child_expr;
2885 : 8282 : Relids new_relids;
2886 : :
2887 [ + + ]: 8282 : if (parent_rel->reloptkind == RELOPT_BASEREL)
2888 : : {
2889 : : /* Simple single-level transformation */
2890 : 6848 : child_expr = (Expr *)
2891 : 13696 : adjust_appendrel_attrs(root,
2892 : 6848 : (Node *) cur_em->em_expr,
2893 : : 1, &appinfo);
2894 : 6848 : }
2895 : : else
2896 : : {
2897 : : /* Must do multi-level transformation */
2898 : 1434 : child_expr = (Expr *)
2899 : 2868 : adjust_appendrel_attrs_multilevel(root,
2900 : 1434 : (Node *) cur_em->em_expr,
2901 : 1434 : child_rel,
2902 : 1434 : child_rel->top_parent);
2903 : : }
2904 : :
2905 : : /*
2906 : : * Transform em_relids to match. Note we do *not* do
2907 : : * pull_varnos(child_expr) here, as for example the
2908 : : * transformation might have substituted a constant, but we
2909 : : * don't want the child member to be marked as constant.
2910 : : */
2911 : 16564 : new_relids = bms_difference(cur_em->em_relids,
2912 : 8282 : top_parent_relids);
2913 : 8282 : new_relids = bms_add_members(new_relids, child_relids);
2914 : :
2915 : 16564 : add_child_eq_member(root,
2916 : 8282 : cur_ec,
2917 : 8282 : i,
2918 : 8282 : child_expr,
2919 : 8282 : new_relids,
2920 : 8282 : cur_em->em_jdomain,
2921 : 8282 : cur_em,
2922 : 8282 : cur_em->em_datatype,
2923 : 8282 : child_rel->relid);
2924 : 8282 : }
2925 : 21159 : }
2926 [ - - + ]: 8653 : }
2927 : 4921 : }
2928 : :
2929 : : /*
2930 : : * add_child_join_rel_equivalences
2931 : : * Like add_child_rel_equivalences(), but for joinrels
2932 : : *
2933 : : * Here we find the ECs relevant to the top parent joinrel and add transformed
2934 : : * member expressions that refer to this child joinrel.
2935 : : *
2936 : : * Note that this function won't be called at all unless we have at least some
2937 : : * reason to believe that the EC members it generates will be useful.
2938 : : */
2939 : : void
2940 : 3015 : add_child_join_rel_equivalences(PlannerInfo *root,
2941 : : int nappinfos, AppendRelInfo **appinfos,
2942 : : RelOptInfo *parent_joinrel,
2943 : : RelOptInfo *child_joinrel)
2944 : : {
2945 : 3015 : Relids top_parent_relids = child_joinrel->top_parent_relids;
2946 : 3015 : Relids child_relids = child_joinrel->relids;
2947 : 3015 : Bitmapset *matching_ecs;
2948 : 3015 : MemoryContext oldcontext;
2949 : 3015 : int i;
2950 : :
2951 [ + - + - : 3015 : Assert(IS_JOIN_REL(child_joinrel) && IS_JOIN_REL(parent_joinrel));
+ + ]
2952 : :
2953 : : /* We need consider only ECs that mention the parent joinrel */
2954 : 3015 : matching_ecs = get_eclass_indexes_for_relids(root, top_parent_relids);
2955 : :
2956 : : /*
2957 : : * If we're being called during GEQO join planning, we still have to
2958 : : * create any new EC members in the main planner context, to avoid having
2959 : : * a corrupt EC data structure after the GEQO context is reset. This is
2960 : : * problematic since we'll leak memory across repeated GEQO cycles. For
2961 : : * now, though, bloat is better than crash. If it becomes a real issue
2962 : : * we'll have to do something to avoid generating duplicate EC members.
2963 : : */
2964 : 3015 : oldcontext = MemoryContextSwitchTo(root->planner_cxt);
2965 : :
2966 : 3015 : i = -1;
2967 [ + + ]: 8067 : while ((i = bms_next_member(matching_ecs, i)) >= 0)
2968 : : {
2969 : 5052 : EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i);
2970 : :
2971 : : /*
2972 : : * If this EC contains a volatile expression, then generating child
2973 : : * EMs would be downright dangerous, so skip it. We rely on a
2974 : : * volatile EC having only one EM.
2975 : : */
2976 [ - + ]: 5052 : if (cur_ec->ec_has_volatile)
2977 : 0 : continue;
2978 : :
2979 : : /* Sanity check on get_eclass_indexes_for_relids result */
2980 [ + - ]: 5052 : Assert(bms_overlap(top_parent_relids, cur_ec->ec_relids));
2981 : :
2982 [ + + + - : 18934 : foreach_node(EquivalenceMember, cur_em, cur_ec->ec_members)
+ + + + ]
2983 : : {
2984 [ + + ]: 8830 : if (cur_em->em_is_const)
2985 : 418 : continue; /* ignore consts here */
2986 : :
2987 : : /* Child members should not exist in ec_members */
2988 [ + - ]: 8412 : Assert(!cur_em->em_is_child);
2989 : :
2990 : : /*
2991 : : * We may ignore expressions that reference a single baserel,
2992 : : * because add_child_rel_equivalences should have handled them.
2993 : : */
2994 [ + + ]: 8412 : if (bms_membership(cur_em->em_relids) != BMS_MULTIPLE)
2995 : 7979 : continue;
2996 : :
2997 : : /* Does this member reference child's topmost parent rel? */
2998 [ - + ]: 433 : if (bms_overlap(cur_em->em_relids, top_parent_relids))
2999 : : {
3000 : : /* Yes, generate transformed child version */
3001 : 433 : Expr *child_expr;
3002 : 433 : Relids new_relids;
3003 : :
3004 [ + + ]: 433 : if (parent_joinrel->reloptkind == RELOPT_JOINREL)
3005 : : {
3006 : : /* Simple single-level transformation */
3007 : 417 : child_expr = (Expr *)
3008 : 834 : adjust_appendrel_attrs(root,
3009 : 417 : (Node *) cur_em->em_expr,
3010 : 417 : nappinfos, appinfos);
3011 : 417 : }
3012 : : else
3013 : : {
3014 : : /* Must do multi-level transformation */
3015 [ + - ]: 16 : Assert(parent_joinrel->reloptkind == RELOPT_OTHER_JOINREL);
3016 : 16 : child_expr = (Expr *)
3017 : 32 : adjust_appendrel_attrs_multilevel(root,
3018 : 16 : (Node *) cur_em->em_expr,
3019 : 16 : child_joinrel,
3020 : 16 : child_joinrel->top_parent);
3021 : : }
3022 : :
3023 : : /*
3024 : : * Transform em_relids to match. Note we do *not* do
3025 : : * pull_varnos(child_expr) here, as for example the
3026 : : * transformation might have substituted a constant, but we
3027 : : * don't want the child member to be marked as constant.
3028 : : */
3029 : 866 : new_relids = bms_difference(cur_em->em_relids,
3030 : 433 : top_parent_relids);
3031 : 433 : new_relids = bms_add_members(new_relids, child_relids);
3032 : :
3033 : : /*
3034 : : * Add new child member to the EquivalenceClass. Because this
3035 : : * is a RELOPT_OTHER_JOINREL which has multiple component
3036 : : * relids, there is no ideal place to store these members in
3037 : : * the class. Ordinarily, child members are stored in the
3038 : : * ec_childmembers[] array element corresponding to their
3039 : : * relid, however, here we have multiple component relids, so
3040 : : * there's no single ec_childmembers[] array element to store
3041 : : * this member. So that we still correctly find this member
3042 : : * in loops iterating over an EquivalenceMemberIterator, we
3043 : : * opt to store the member in the ec_childmembers array in
3044 : : * only the first component relid slot of the array. This
3045 : : * allows the member to be found, providing callers of
3046 : : * setup_eclass_member_iterator() specify all the component
3047 : : * relids for the RELOPT_OTHER_JOINREL, which they do. If we
3048 : : * opted to store the member in each ec_childmembers[] element
3049 : : * for all the component relids, then that would just result
3050 : : * in eclass_member_iterator_next() finding the member
3051 : : * multiple times, which is a waste of effort.
3052 : : */
3053 : 866 : add_child_eq_member(root,
3054 : 433 : cur_ec,
3055 : : -1,
3056 : 433 : child_expr,
3057 : 433 : new_relids,
3058 : 433 : cur_em->em_jdomain,
3059 : 433 : cur_em,
3060 : 433 : cur_em->em_datatype,
3061 : 433 : bms_next_member(child_joinrel->relids, -1));
3062 : 433 : }
3063 : 5485 : }
3064 [ - - + ]: 5052 : }
3065 : :
3066 : 3015 : MemoryContextSwitchTo(oldcontext);
3067 : 3015 : }
3068 : :
3069 : : /*
3070 : : * add_setop_child_rel_equivalences
3071 : : * Add equivalence members for each non-resjunk target in 'child_tlist'
3072 : : * to the EquivalenceClass in the corresponding setop_pathkey's pk_eclass.
3073 : : *
3074 : : * 'root' is the PlannerInfo belonging to the top-level set operation.
3075 : : * 'child_rel' is the RelOptInfo of the child relation we're adding
3076 : : * EquivalenceMembers for.
3077 : : * 'child_tlist' is the target list for the setop child relation. The target
3078 : : * list expressions are what we add as EquivalenceMembers.
3079 : : * 'setop_pathkeys' is a list of PathKeys which must contain an entry for each
3080 : : * non-resjunk target in 'child_tlist'.
3081 : : */
3082 : : void
3083 : 1905 : add_setop_child_rel_equivalences(PlannerInfo *root, RelOptInfo *child_rel,
3084 : : List *child_tlist, List *setop_pathkeys)
3085 : : {
3086 : 1905 : ListCell *lc;
3087 : 1905 : ListCell *lc2 = list_head(setop_pathkeys);
3088 : :
3089 [ + - + + : 7422 : foreach(lc, child_tlist)
+ + ]
3090 : : {
3091 : 5517 : TargetEntry *tle = lfirst_node(TargetEntry, lc);
3092 : 5517 : EquivalenceMember *parent_em;
3093 : 5517 : PathKey *pk;
3094 : :
3095 [ - + ]: 5517 : if (tle->resjunk)
3096 : 0 : continue;
3097 : :
3098 [ + - ]: 5517 : if (lc2 == NULL)
3099 [ # # # # ]: 0 : elog(ERROR, "too few pathkeys for set operation");
3100 : :
3101 : 5517 : pk = lfirst_node(PathKey, lc2);
3102 : 5517 : parent_em = linitial(pk->pk_eclass->ec_members);
3103 : :
3104 : : /*
3105 : : * We can safely pass the parent member as the first member in the
3106 : : * ec_members list as this is added first in generate_union_paths,
3107 : : * likewise, the JoinDomain can be that of the initial member of the
3108 : : * Pathkey's EquivalenceClass. We pass -1 for ec_index since we
3109 : : * maintain the eclass_indexes for the child_rel after the loop.
3110 : : */
3111 : 11034 : add_child_eq_member(root,
3112 : 5517 : pk->pk_eclass,
3113 : : -1,
3114 : 5517 : tle->expr,
3115 : 5517 : child_rel->relids,
3116 : 5517 : parent_em->em_jdomain,
3117 : 5517 : parent_em,
3118 : 5517 : exprType((Node *) tle->expr),
3119 : 5517 : child_rel->relid);
3120 : :
3121 : 5517 : lc2 = lnext(setop_pathkeys, lc2);
3122 [ - - + ]: 5517 : }
3123 : :
3124 : : /*
3125 : : * transformSetOperationStmt() ensures that the targetlist never contains
3126 : : * any resjunk columns, so all eclasses that exist in 'root' must have
3127 : : * received a new member in the loop above. Add them to the child_rel's
3128 : : * eclass_indexes.
3129 : : */
3130 : 3810 : child_rel->eclass_indexes = bms_add_range(child_rel->eclass_indexes, 0,
3131 : 1905 : list_length(root->eq_classes) - 1);
3132 : 1905 : }
3133 : :
3134 : : /*
3135 : : * setup_eclass_member_iterator
3136 : : * Setup an EquivalenceMemberIterator 'it' to iterate over all parent
3137 : : * EquivalenceMembers and child members belonging to the given 'ec'.
3138 : : *
3139 : : * This iterator returns:
3140 : : * - All parent members stored directly in ec_members for 'ec', and;
3141 : : * - Any child member added to the given ec by add_child_eq_member() where
3142 : : * the child_relid specified in the add_child_eq_member() call is a member
3143 : : * of the 'child_relids' parameter.
3144 : : *
3145 : : * Note:
3146 : : * The given 'child_relids' must remain allocated and not be changed for the
3147 : : * lifetime of the iterator.
3148 : : *
3149 : : * Parameters:
3150 : : * 'it' is a pointer to the iterator to set up. Normally stack allocated.
3151 : : * 'ec' is the EquivalenceClass from which to iterate members for.
3152 : : * 'child_relids' is the relids to return child members for.
3153 : : */
3154 : : void
3155 : 452805 : setup_eclass_member_iterator(EquivalenceMemberIterator *it,
3156 : : EquivalenceClass *ec, Relids child_relids)
3157 : : {
3158 : 452805 : it->ec = ec;
3159 : : /* no need to set this if the class has no child members array set */
3160 [ + + ]: 452805 : it->child_relids = ec->ec_childmembers != NULL ? child_relids : NULL;
3161 : 452805 : it->current_relid = -1;
3162 : 452805 : it->current_list = ec->ec_members;
3163 : 452805 : it->current_cell = list_head(it->current_list);
3164 : 452805 : }
3165 : :
3166 : : /*
3167 : : * eclass_member_iterator_next
3168 : : * Get the next EquivalenceMember from the EquivalenceMemberIterator 'it',
3169 : : * as setup by setup_eclass_member_iterator(). NULL is returned if there
3170 : : * are no members left, after which callers must not call
3171 : : * eclass_member_iterator_next() again for the given iterator.
3172 : : */
3173 : : EquivalenceMember *
3174 : 1023331 : eclass_member_iterator_next(EquivalenceMemberIterator *it)
3175 : : {
3176 [ + + ]: 1023331 : while (it->current_list != NULL)
3177 : : {
3178 [ + + ]: 1019971 : while (it->current_cell != NULL)
3179 : : {
3180 : 700662 : EquivalenceMember *em;
3181 : :
3182 : : nextcell:
3183 : 722395 : em = lfirst_node(EquivalenceMember, it->current_cell);
3184 : 722395 : it->current_cell = lnext(it->current_list, it->current_cell);
3185 : 722395 : return em;
3186 : : }
3187 : :
3188 : : /* Search for the next list to return members from */
3189 [ + + ]: 338527 : while ((it->current_relid = bms_next_member(it->child_relids, it->current_relid)) > 0)
3190 : : {
3191 : : /*
3192 : : * Be paranoid in case we're given relids above what we've sized
3193 : : * the ec_childmembers array to.
3194 : : */
3195 [ - + ]: 40951 : if (it->current_relid >= it->ec->ec_childmembers_size)
3196 : 0 : return NULL;
3197 : :
3198 : 40951 : it->current_list = it->ec->ec_childmembers[it->current_relid];
3199 : :
3200 : : /* If there are members in this list, use it. */
3201 [ + + ]: 40951 : if (it->current_list != NIL)
3202 : : {
3203 : : /* point current_cell to the head of this list */
3204 : 21733 : it->current_cell = list_head(it->current_list);
3205 : 21733 : goto nextcell;
3206 : : }
3207 : : }
3208 : 297576 : return NULL;
3209 : : }
3210 : :
3211 : 3360 : return NULL;
3212 : 1023331 : }
3213 : :
3214 : : /*
3215 : : * generate_implied_equalities_for_column
3216 : : * Create EC-derived joinclauses usable with a specific column.
3217 : : *
3218 : : * This is used by indxpath.c to extract potentially indexable joinclauses
3219 : : * from ECs, and can be used by foreign data wrappers for similar purposes.
3220 : : * We assume that only expressions in Vars of a single table are of interest,
3221 : : * but the caller provides a callback function to identify exactly which
3222 : : * such expressions it would like to know about.
3223 : : *
3224 : : * We assume that any given table/index column could appear in only one EC.
3225 : : * (This should be true in all but the most pathological cases, and if it
3226 : : * isn't, we stop on the first match anyway.) Therefore, what we return
3227 : : * is a redundant list of clauses equating the table/index column to each of
3228 : : * the other-relation values it is known to be equal to. Any one of
3229 : : * these clauses can be used to create a parameterized path, and there
3230 : : * is no value in using more than one. (But it *is* worthwhile to create
3231 : : * a separate parameterized path for each one, since that leads to different
3232 : : * join orders.)
3233 : : *
3234 : : * The caller can pass a Relids set of rels we aren't interested in joining
3235 : : * to, so as to save the work of creating useless clauses.
3236 : : */
3237 : : List *
3238 : 57379 : generate_implied_equalities_for_column(PlannerInfo *root,
3239 : : RelOptInfo *rel,
3240 : : ec_matches_callback_type callback,
3241 : : void *callback_arg,
3242 : : Relids prohibited_rels)
3243 : : {
3244 : 57379 : List *result = NIL;
3245 : 57379 : bool is_child_rel = (rel->reloptkind == RELOPT_OTHER_MEMBER_REL);
3246 : 57379 : Relids parent_relids;
3247 : 57379 : int i;
3248 : :
3249 : : /* Should be OK to rely on eclass_indexes */
3250 [ + - ]: 57379 : Assert(root->ec_merging_done);
3251 : :
3252 : : /* Indexes are available only on base or "other" member relations. */
3253 [ + + + - ]: 57379 : Assert(IS_SIMPLE_REL(rel));
3254 : :
3255 : : /* If it's a child rel, we'll need to know what its parent(s) are */
3256 [ + + ]: 57379 : if (is_child_rel)
3257 : 2305 : parent_relids = find_childrel_parents(root, rel);
3258 : : else
3259 : 55074 : parent_relids = NULL; /* not used, but keep compiler quiet */
3260 : :
3261 : 57379 : i = -1;
3262 [ + + ]: 179960 : while ((i = bms_next_member(rel->eclass_indexes, i)) >= 0)
3263 : : {
3264 : 122581 : EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i);
3265 : 122581 : EquivalenceMemberIterator it;
3266 : 122581 : EquivalenceMember *cur_em;
3267 : 122581 : ListCell *lc2;
3268 : :
3269 : : /* Sanity check eclass_indexes only contain ECs for rel */
3270 [ + + + - ]: 122581 : Assert(is_child_rel || bms_is_subset(rel->relids, cur_ec->ec_relids));
3271 : :
3272 : : /*
3273 : : * Won't generate joinclauses if const or single-member (the latter
3274 : : * test covers the volatile case too)
3275 : : */
3276 [ + + + + ]: 122581 : if (cur_ec->ec_has_const || list_length(cur_ec->ec_members) <= 1)
3277 : 66052 : continue;
3278 : :
3279 : : /*
3280 : : * Scan members, looking for a match to the target column. Note that
3281 : : * child EC members are considered, but only when they belong to the
3282 : : * target relation. (Unlike regular members, the same expression
3283 : : * could be a child member of more than one EC. Therefore, it's
3284 : : * potentially order-dependent which EC a child relation's target
3285 : : * column gets matched to. This is annoying but it only happens in
3286 : : * corner cases, so for now we live with just reporting the first
3287 : : * match. See also get_eclass_for_sort_expr.)
3288 : : */
3289 : 56529 : setup_eclass_member_iterator(&it, cur_ec, rel->relids);
3290 [ + + ]: 157875 : while ((cur_em = eclass_member_iterator_next(&it)) != NULL)
3291 : : {
3292 [ + + + + ]: 112436 : if (bms_equal(cur_em->em_relids, rel->relids) &&
3293 : 56722 : callback(root, rel, cur_ec, cur_em, callback_arg))
3294 : 11090 : break;
3295 : : }
3296 : :
3297 [ + + ]: 56529 : if (!cur_em)
3298 : 45439 : continue;
3299 : :
3300 : : /*
3301 : : * Found our match. Scan the other EC members and attempt to generate
3302 : : * joinclauses. Ignore children here.
3303 : : */
3304 [ + - + + : 33838 : foreach(lc2, cur_ec->ec_members)
+ + ]
3305 : : {
3306 : 22748 : EquivalenceMember *other_em = (EquivalenceMember *) lfirst(lc2);
3307 : 22748 : Oid eq_op;
3308 : 22748 : RestrictInfo *rinfo;
3309 : :
3310 : : /* Child members should not exist in ec_members */
3311 [ + - ]: 22748 : Assert(!other_em->em_is_child);
3312 : :
3313 : : /* Make sure it'll be a join to a different rel */
3314 [ + + + + ]: 22748 : if (other_em == cur_em ||
3315 : 12232 : bms_overlap(other_em->em_relids, rel->relids))
3316 : 10575 : continue;
3317 : :
3318 : : /* Forget it if caller doesn't want joins to this rel */
3319 [ + + ]: 12173 : if (bms_overlap(other_em->em_relids, prohibited_rels))
3320 : 26 : continue;
3321 : :
3322 : : /*
3323 : : * Also, if this is a child rel, avoid generating a useless join
3324 : : * to its parent rel(s).
3325 : : */
3326 [ + + + + ]: 12147 : if (is_child_rel &&
3327 : 1313 : bms_overlap(parent_relids, other_em->em_relids))
3328 : 588 : continue;
3329 : :
3330 : 23118 : eq_op = select_equality_operator(cur_ec,
3331 : 11559 : cur_em->em_datatype,
3332 : 11559 : other_em->em_datatype);
3333 [ + - ]: 11559 : if (!OidIsValid(eq_op))
3334 : 0 : continue;
3335 : :
3336 : : /* set parent_ec to mark as redundant with other joinclauses */
3337 : 23118 : rinfo = create_join_clause(root, cur_ec, eq_op,
3338 : 11559 : cur_em, other_em,
3339 : 11559 : cur_ec);
3340 : :
3341 : 11559 : result = lappend(result, rinfo);
3342 [ + + ]: 22748 : }
3343 : :
3344 : : /*
3345 : : * If somehow we failed to create any join clauses, we might as well
3346 : : * keep scanning the ECs for another match. But if we did make any,
3347 : : * we're done, because we don't want to return non-redundant clauses.
3348 : : */
3349 [ + + ]: 11090 : if (result)
3350 : 11016 : break;
3351 [ + + ]: 122581 : }
3352 : :
3353 : 114758 : return result;
3354 : 57379 : }
3355 : :
3356 : : /*
3357 : : * have_relevant_eclass_joinclause
3358 : : * Detect whether there is an EquivalenceClass that could produce
3359 : : * a joinclause involving the two given relations.
3360 : : *
3361 : : * This is essentially a very cut-down version of
3362 : : * generate_join_implied_equalities(). Note it's OK to occasionally say "yes"
3363 : : * incorrectly. Hence we don't bother with details like whether the lack of a
3364 : : * cross-type operator might prevent the clause from actually being generated.
3365 : : * False negatives are not always fatal either: they will discourage, but not
3366 : : * completely prevent, investigation of particular join pathways.
3367 : : */
3368 : : bool
3369 : 17393 : have_relevant_eclass_joinclause(PlannerInfo *root,
3370 : : RelOptInfo *rel1, RelOptInfo *rel2)
3371 : : {
3372 : 17393 : Bitmapset *matching_ecs;
3373 : 17393 : int i;
3374 : :
3375 : : /*
3376 : : * Examine only eclasses mentioning both rel1 and rel2.
3377 : : *
3378 : : * Note that we do not consider the possibility of an eclass generating
3379 : : * "join" clauses that mention just one of the rels plus an outer join
3380 : : * that could be formed from them. Although such clauses must be
3381 : : * correctly enforced when we form the outer join, they don't seem like
3382 : : * sufficient reason to prioritize this join over other ones. The join
3383 : : * ordering rules will force the join to be made when necessary.
3384 : : */
3385 : 34786 : matching_ecs = get_common_eclass_indexes(root, rel1->relids,
3386 : 17393 : rel2->relids);
3387 : :
3388 : 17393 : i = -1;
3389 [ + + ]: 17396 : while ((i = bms_next_member(matching_ecs, i)) >= 0)
3390 : : {
3391 : 28370 : EquivalenceClass *ec = (EquivalenceClass *) list_nth(root->eq_classes,
3392 : 14185 : i);
3393 : :
3394 : : /*
3395 : : * Sanity check that get_common_eclass_indexes gave only ECs
3396 : : * containing both rels.
3397 : : */
3398 [ + - ]: 14185 : Assert(bms_overlap(rel1->relids, ec->ec_relids));
3399 [ + - ]: 14185 : Assert(bms_overlap(rel2->relids, ec->ec_relids));
3400 : :
3401 : : /*
3402 : : * Won't generate joinclauses if single-member (this test covers the
3403 : : * volatile case too)
3404 : : */
3405 [ + + ]: 14185 : if (list_length(ec->ec_members) <= 1)
3406 : 3 : continue;
3407 : :
3408 : : /*
3409 : : * We do not need to examine the individual members of the EC, because
3410 : : * all that we care about is whether each rel overlaps the relids of
3411 : : * at least one member, and get_common_eclass_indexes() and the single
3412 : : * member check above are sufficient to prove that. (As with
3413 : : * have_relevant_joinclause(), it is not necessary that the EC be able
3414 : : * to form a joinclause relating exactly the two given rels, only that
3415 : : * it be able to form a joinclause mentioning both, and this will
3416 : : * surely be true if both of them overlap ec_relids.)
3417 : : *
3418 : : * Note we don't test ec_broken; if we did, we'd need a separate code
3419 : : * path to look through ec_sources. Checking the membership anyway is
3420 : : * OK as a possibly-overoptimistic heuristic.
3421 : : *
3422 : : * We don't test ec_has_const either, even though a const eclass won't
3423 : : * generate real join clauses. This is because if we had "WHERE a.x =
3424 : : * b.y and a.x = 42", it is worth considering a join between a and b,
3425 : : * since the join result is likely to be small even though it'll end
3426 : : * up being an unqualified nestloop.
3427 : : */
3428 : :
3429 : 14182 : return true;
3430 [ + + ]: 14185 : }
3431 : :
3432 : 3211 : return false;
3433 : 17393 : }
3434 : :
3435 : :
3436 : : /*
3437 : : * has_relevant_eclass_joinclause
3438 : : * Detect whether there is an EquivalenceClass that could produce
3439 : : * a joinclause involving the given relation and anything else.
3440 : : *
3441 : : * This is the same as have_relevant_eclass_joinclause with the other rel
3442 : : * implicitly defined as "everything else in the query".
3443 : : */
3444 : : bool
3445 : 18791 : has_relevant_eclass_joinclause(PlannerInfo *root, RelOptInfo *rel1)
3446 : : {
3447 : 18791 : Bitmapset *matched_ecs;
3448 : 18791 : int i;
3449 : :
3450 : : /* Examine only eclasses mentioning rel1 */
3451 : 18791 : matched_ecs = get_eclass_indexes_for_relids(root, rel1->relids);
3452 : :
3453 : 18791 : i = -1;
3454 [ + + ]: 61536 : while ((i = bms_next_member(matched_ecs, i)) >= 0)
3455 : : {
3456 : 98814 : EquivalenceClass *ec = (EquivalenceClass *) list_nth(root->eq_classes,
3457 : 49407 : i);
3458 : :
3459 : : /*
3460 : : * Won't generate joinclauses if single-member (this test covers the
3461 : : * volatile case too)
3462 : : */
3463 [ + + ]: 49407 : if (list_length(ec->ec_members) <= 1)
3464 : 21496 : continue;
3465 : :
3466 : : /*
3467 : : * Per the comment in have_relevant_eclass_joinclause, it's sufficient
3468 : : * to find an EC that mentions both this rel and some other rel.
3469 : : */
3470 [ + + ]: 27911 : if (!bms_is_subset(ec->ec_relids, rel1->relids))
3471 : 6662 : return true;
3472 [ + + + ]: 49407 : }
3473 : :
3474 : 12129 : return false;
3475 : 18791 : }
3476 : :
3477 : :
3478 : : /*
3479 : : * eclass_useful_for_merging
3480 : : * Detect whether the EC could produce any mergejoinable join clauses
3481 : : * against the specified relation.
3482 : : *
3483 : : * This is just a heuristic test and doesn't have to be exact; it's better
3484 : : * to say "yes" incorrectly than "no". Hence we don't bother with details
3485 : : * like whether the lack of a cross-type operator might prevent the clause
3486 : : * from actually being generated.
3487 : : */
3488 : : bool
3489 : 59906 : eclass_useful_for_merging(PlannerInfo *root,
3490 : : EquivalenceClass *eclass,
3491 : : RelOptInfo *rel)
3492 : : {
3493 : 59906 : Relids relids;
3494 : 59906 : ListCell *lc;
3495 : :
3496 [ + - ]: 59906 : Assert(!eclass->ec_merged);
3497 : :
3498 : : /*
3499 : : * Won't generate joinclauses if const or single-member (the latter test
3500 : : * covers the volatile case too)
3501 : : */
3502 [ + - + + ]: 59906 : if (eclass->ec_has_const || list_length(eclass->ec_members) <= 1)
3503 : 3392 : return false;
3504 : :
3505 : : /*
3506 : : * Note we don't test ec_broken; if we did, we'd need a separate code path
3507 : : * to look through ec_sources. Checking the members anyway is OK as a
3508 : : * possibly-overoptimistic heuristic.
3509 : : */
3510 : :
3511 : : /* If specified rel is a child, we must consider the topmost parent rel */
3512 [ + + + + : 56514 : if (IS_OTHER_REL(rel))
- + ]
3513 : : {
3514 [ + - ]: 1337 : Assert(!bms_is_empty(rel->top_parent_relids));
3515 : 1337 : relids = rel->top_parent_relids;
3516 : 1337 : }
3517 : : else
3518 : 55177 : relids = rel->relids;
3519 : :
3520 : : /* If rel already includes all members of eclass, no point in searching */
3521 [ + + ]: 56514 : if (bms_is_subset(eclass->ec_relids, relids))
3522 : 21016 : return false;
3523 : :
3524 : : /*
3525 : : * To join, we need a member not in the given rel. Ignore children here.
3526 : : */
3527 [ + - + + : 92288 : foreach(lc, eclass->ec_members)
+ + + + ]
3528 : : {
3529 : 56790 : EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
3530 : :
3531 : : /* Child members should not exist in ec_members */
3532 [ + - ]: 56790 : Assert(!cur_em->em_is_child);
3533 : :
3534 [ + + ]: 56790 : if (!bms_overlap(cur_em->em_relids, relids))
3535 : 35381 : return true;
3536 [ + + ]: 56790 : }
3537 : :
3538 : 117 : return false;
3539 : 59906 : }
3540 : :
3541 : :
3542 : : /*
3543 : : * is_redundant_derived_clause
3544 : : * Test whether rinfo is derived from same EC as any clause in clauselist;
3545 : : * if so, it can be presumed to represent a condition that's redundant
3546 : : * with that member of the list.
3547 : : */
3548 : : bool
3549 : 14 : is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist)
3550 : : {
3551 : 14 : EquivalenceClass *parent_ec = rinfo->parent_ec;
3552 : 14 : ListCell *lc;
3553 : :
3554 : : /* Fail if it's not a potentially-redundant clause from some EC */
3555 [ - + ]: 14 : if (parent_ec == NULL)
3556 : 14 : return false;
3557 : :
3558 [ # # # # : 0 : foreach(lc, clauselist)
# # # # ]
3559 : : {
3560 : 0 : RestrictInfo *otherrinfo = (RestrictInfo *) lfirst(lc);
3561 : :
3562 [ # # ]: 0 : if (otherrinfo->parent_ec == parent_ec)
3563 : 0 : return true;
3564 [ # # ]: 0 : }
3565 : :
3566 : 0 : return false;
3567 : 14 : }
3568 : :
3569 : : /*
3570 : : * is_redundant_with_indexclauses
3571 : : * Test whether rinfo is redundant with any clause in the IndexClause
3572 : : * list. Here, for convenience, we test both simple identity and
3573 : : * whether it is derived from the same EC as any member of the list.
3574 : : */
3575 : : bool
3576 : 123412 : is_redundant_with_indexclauses(RestrictInfo *rinfo, List *indexclauses)
3577 : : {
3578 : 123412 : EquivalenceClass *parent_ec = rinfo->parent_ec;
3579 : 123412 : ListCell *lc;
3580 : :
3581 [ + + + + : 245438 : foreach(lc, indexclauses)
+ + + + ]
3582 : : {
3583 : 122026 : IndexClause *iclause = lfirst_node(IndexClause, lc);
3584 : 122026 : RestrictInfo *otherrinfo = iclause->rinfo;
3585 : :
3586 : : /* If indexclause is lossy, it won't enforce the condition exactly */
3587 [ + + ]: 122026 : if (iclause->lossy)
3588 : 1040 : continue;
3589 : :
3590 : : /* Match if it's same clause (pointer equality should be enough) */
3591 [ + + ]: 120986 : if (rinfo == otherrinfo)
3592 : 81714 : return true;
3593 : : /* Match if derived from same EC */
3594 [ + + + + ]: 39272 : if (parent_ec && otherrinfo->parent_ec == parent_ec)
3595 : 75 : return true;
3596 : :
3597 : : /*
3598 : : * No need to look at the derived clauses in iclause->indexquals; they
3599 : : * couldn't match if the parent clause didn't.
3600 : : */
3601 [ + + + ]: 122026 : }
3602 : :
3603 : 41623 : return false;
3604 : 123412 : }
3605 : :
3606 : : /*
3607 : : * get_eclass_indexes_for_relids
3608 : : * Build and return a Bitmapset containing the indexes into root's
3609 : : * eq_classes list for all eclasses that mention any of these relids
3610 : : */
3611 : : static Bitmapset *
3612 : 94827 : get_eclass_indexes_for_relids(PlannerInfo *root, Relids relids)
3613 : : {
3614 : 94827 : Bitmapset *ec_indexes = NULL;
3615 : 94827 : int i = -1;
3616 : :
3617 : : /* Should be OK to rely on eclass_indexes */
3618 [ + - ]: 94827 : Assert(root->ec_merging_done);
3619 : :
3620 [ + + ]: 278536 : while ((i = bms_next_member(relids, i)) > 0)
3621 : : {
3622 : 183709 : RelOptInfo *rel = root->simple_rel_array[i];
3623 : :
3624 : : /* ignore the RTE_GROUP RTE */
3625 [ - + ]: 183709 : if (i == root->group_rtindex)
3626 : 0 : continue;
3627 : :
3628 [ + + ]: 183709 : if (rel == NULL) /* must be an outer join */
3629 : : {
3630 [ - + ]: 18071 : Assert(bms_is_member(i, root->outer_join_rels));
3631 : 18071 : continue;
3632 : : }
3633 : :
3634 : 165638 : ec_indexes = bms_add_members(ec_indexes, rel->eclass_indexes);
3635 [ - + + ]: 183709 : }
3636 : 189654 : return ec_indexes;
3637 : 94827 : }
3638 : :
3639 : : /*
3640 : : * get_common_eclass_indexes
3641 : : * Build and return a Bitmapset containing the indexes into root's
3642 : : * eq_classes list for all eclasses that mention rels in both
3643 : : * relids1 and relids2.
3644 : : */
3645 : : static Bitmapset *
3646 : 56273 : get_common_eclass_indexes(PlannerInfo *root, Relids relids1, Relids relids2)
3647 : : {
3648 : 56273 : Bitmapset *rel1ecs;
3649 : 56273 : Bitmapset *rel2ecs;
3650 : 56273 : int relid;
3651 : :
3652 : 56273 : rel1ecs = get_eclass_indexes_for_relids(root, relids1);
3653 : :
3654 : : /*
3655 : : * We can get away with just using the relation's eclass_indexes directly
3656 : : * when relids2 is a singleton set.
3657 : : */
3658 [ + + ]: 56273 : if (bms_get_singleton_member(relids2, &relid))
3659 : 45157 : rel2ecs = root->simple_rel_array[relid]->eclass_indexes;
3660 : : else
3661 : 11116 : rel2ecs = get_eclass_indexes_for_relids(root, relids2);
3662 : :
3663 : : /* Calculate and return the common EC indexes, recycling the left input. */
3664 : 112546 : return bms_int_members(rel1ecs, rel2ecs);
3665 : 56273 : }
3666 : :
3667 : : /*
3668 : : * ec_build_derives_hash
3669 : : * Construct the auxiliary hash table for derived clause lookups.
3670 : : */
3671 : : static void
3672 : 0 : ec_build_derives_hash(PlannerInfo *root, EquivalenceClass *ec)
3673 : : {
3674 [ # # ]: 0 : Assert(!ec->ec_derives_hash);
3675 : :
3676 : : /*
3677 : : * Create the hash table.
3678 : : *
3679 : : * We pass list_length(ec->ec_derives_list) as the initial size.
3680 : : * Simplehash will divide this by the fillfactor (typically 0.9) and round
3681 : : * up to the next power of two, so this will usually give us at least 64
3682 : : * buckets around the threshold. That avoids immediate resizing without
3683 : : * hardcoding a specific size.
3684 : : */
3685 : 0 : ec->ec_derives_hash = derives_create(root->planner_cxt,
3686 : 0 : list_length(ec->ec_derives_list),
3687 : : NULL);
3688 : :
3689 [ # # # # : 0 : foreach_node(RestrictInfo, rinfo, ec->ec_derives_list)
# # # # ]
3690 : 0 : ec_add_clause_to_derives_hash(ec, rinfo);
3691 : 0 : }
3692 : :
3693 : : /*
3694 : : * ec_add_derived_clause
3695 : : * Add a clause to the set of derived clauses for the given
3696 : : * EquivalenceClass. Always appends to ec_derives_list; also adds
3697 : : * to ec_derives_hash if it exists.
3698 : : *
3699 : : * Also asserts expected invariants of derived clauses.
3700 : : */
3701 : : static void
3702 : 11012 : ec_add_derived_clause(EquivalenceClass *ec, RestrictInfo *clause)
3703 : : {
3704 : : /*
3705 : : * Constant, if present, is always placed on the RHS; see
3706 : : * generate_base_implied_equalities_const(). LHS is never a constant.
3707 : : */
3708 [ + - ]: 11012 : Assert(!clause->left_em->em_is_const);
3709 : :
3710 : : /*
3711 : : * Clauses containing a constant are never considered redundant, so
3712 : : * parent_ec is not set.
3713 : : */
3714 [ + + + - ]: 11012 : Assert(!clause->parent_ec || !clause->right_em->em_is_const);
3715 : :
3716 : 11012 : ec->ec_derives_list = lappend(ec->ec_derives_list, clause);
3717 [ + - ]: 11012 : if (ec->ec_derives_hash)
3718 : 0 : ec_add_clause_to_derives_hash(ec, clause);
3719 : 11012 : }
3720 : :
3721 : : /*
3722 : : * ec_add_derived_clauses
3723 : : * Add a list of clauses to the set of clauses derived from the given
3724 : : * EquivalenceClass; adding to the list and hash table if needed.
3725 : : *
3726 : : * This function is similar to ec_add_derived_clause() but optimized for adding
3727 : : * multiple clauses at a time to the ec_derives_list. The assertions from
3728 : : * ec_add_derived_clause() are not repeated here, as the input clauses are
3729 : : * assumed to have already been validated.
3730 : : */
3731 : : static void
3732 : 6 : ec_add_derived_clauses(EquivalenceClass *ec, List *clauses)
3733 : : {
3734 : 6 : ec->ec_derives_list = list_concat(ec->ec_derives_list, clauses);
3735 [ + - ]: 6 : if (ec->ec_derives_hash)
3736 [ # # # # : 0 : foreach_node(RestrictInfo, rinfo, clauses)
# # # # ]
3737 : 0 : ec_add_clause_to_derives_hash(ec, rinfo);
3738 : 6 : }
3739 : :
3740 : : /*
3741 : : * fill_ec_derives_key
3742 : : * Compute a canonical key for ec_derives_hash lookup or insertion.
3743 : : *
3744 : : * Derived clauses are looked up using a pair of EquivalenceMembers and a
3745 : : * parent EquivalenceClass. To avoid storing or searching for both EM orderings,
3746 : : * we canonicalize the key:
3747 : : *
3748 : : * - For clauses involving two non-constant EMs, em1 is set to the EM with lower
3749 : : * memory address and em2 is set to the other one.
3750 : : * - For clauses involving a constant EM, the caller must pass the non-constant
3751 : : * EM as leftem and NULL as rightem; we then set em1 = NULL and em2 = leftem.
3752 : : */
3753 : : static inline void
3754 : 0 : fill_ec_derives_key(ECDerivesKey *key,
3755 : : EquivalenceMember *leftem,
3756 : : EquivalenceMember *rightem,
3757 : : EquivalenceClass *parent_ec)
3758 : : {
3759 [ # # ]: 0 : Assert(leftem); /* Always required for lookup or insertion */
3760 : :
3761 [ # # ]: 0 : if (rightem == NULL)
3762 : : {
3763 : 0 : key->em1 = NULL;
3764 : 0 : key->em2 = leftem;
3765 : 0 : }
3766 [ # # ]: 0 : else if (leftem < rightem)
3767 : : {
3768 : 0 : key->em1 = leftem;
3769 : 0 : key->em2 = rightem;
3770 : 0 : }
3771 : : else
3772 : : {
3773 : 0 : key->em1 = rightem;
3774 : 0 : key->em2 = leftem;
3775 : : }
3776 : 0 : key->parent_ec = parent_ec;
3777 : 0 : }
3778 : :
3779 : : /*
3780 : : * ec_add_clause_to_derives_hash
3781 : : * Add a derived clause to ec_derives_hash in the given EquivalenceClass.
3782 : : *
3783 : : * Each clause is associated with a canonicalized key. For constant-containing
3784 : : * clauses, only the non-constant EM is used for lookup; see comments in
3785 : : * fill_ec_derives_key().
3786 : : */
3787 : : static void
3788 : 0 : ec_add_clause_to_derives_hash(EquivalenceClass *ec, RestrictInfo *rinfo)
3789 : : {
3790 : 0 : ECDerivesKey key;
3791 : 0 : ECDerivesEntry *entry;
3792 : 0 : bool found;
3793 : :
3794 : : /*
3795 : : * Constants are always placed on the RHS; see
3796 : : * generate_base_implied_equalities_const().
3797 : : */
3798 [ # # ]: 0 : Assert(!rinfo->left_em->em_is_const);
3799 : :
3800 : : /*
3801 : : * Clauses containing a constant are never considered redundant, so
3802 : : * parent_ec is not set.
3803 : : */
3804 [ # # # # ]: 0 : Assert(!rinfo->parent_ec || !rinfo->right_em->em_is_const);
3805 : :
3806 : : /*
3807 : : * See fill_ec_derives_key() for details: we use a canonicalized key to
3808 : : * avoid storing both EM orderings. For constant EMs, only the
3809 : : * non-constant EM is included in the key.
3810 : : */
3811 : 0 : fill_ec_derives_key(&key,
3812 : 0 : rinfo->left_em,
3813 [ # # ]: 0 : rinfo->right_em->em_is_const ? NULL : rinfo->right_em,
3814 : 0 : rinfo->parent_ec);
3815 : 0 : entry = derives_insert(ec->ec_derives_hash, key, &found);
3816 [ # # ]: 0 : Assert(!found);
3817 : 0 : entry->rinfo = rinfo;
3818 : 0 : }
3819 : :
3820 : : /*
3821 : : * ec_clear_derived_clauses
3822 : : * Reset ec_derives_list and ec_derives_hash.
3823 : : *
3824 : : * We destroy the hash table explicitly, since it may consume significant
3825 : : * space. The list holds the same set of entries and can become equally large
3826 : : * when thousands of partitions are involved, so we free it as well -- even
3827 : : * though we do not typically free lists.
3828 : : */
3829 : : void
3830 : 1926 : ec_clear_derived_clauses(EquivalenceClass *ec)
3831 : : {
3832 : 1926 : list_free(ec->ec_derives_list);
3833 : 1926 : ec->ec_derives_list = NIL;
3834 : :
3835 [ + - ]: 1926 : if (ec->ec_derives_hash)
3836 : : {
3837 : 0 : derives_destroy(ec->ec_derives_hash);
3838 : 0 : ec->ec_derives_hash = NULL;
3839 : 0 : }
3840 : 1926 : }
3841 : :
3842 : : /*
3843 : : * ec_search_clause_for_ems
3844 : : * Search for an existing RestrictInfo that equates the given pair
3845 : : * of EquivalenceMembers, either from ec_sources or ec_derives.
3846 : : *
3847 : : * Returns a clause with matching operands in either given order or commuted
3848 : : * order. We used to require matching operator OIDs, but dropped that since any
3849 : : * semantically different operator here would indicate a broken operator family.
3850 : : *
3851 : : * Returns NULL if no matching clause is found.
3852 : : */
3853 : : static RestrictInfo *
3854 : 42604 : ec_search_clause_for_ems(PlannerInfo *root, EquivalenceClass *ec,
3855 : : EquivalenceMember *leftem, EquivalenceMember *rightem,
3856 : : EquivalenceClass *parent_ec)
3857 : : {
3858 : : /* Check original source clauses */
3859 [ + + + - : 133817 : foreach_node(RestrictInfo, rinfo, ec->ec_sources)
+ + + + +
+ - + + ]
3860 : : {
3861 [ + + ]: 48886 : if (rinfo->left_em == leftem &&
3862 [ + + + + ]: 24346 : rinfo->right_em == rightem &&
3863 : 22023 : rinfo->parent_ec == parent_ec)
3864 : 18 : return rinfo;
3865 [ + + ]: 48868 : if (rinfo->left_em == rightem &&
3866 [ + + + + ]: 19796 : rinfo->right_em == leftem &&
3867 : 17843 : rinfo->parent_ec == parent_ec)
3868 : 259 : return rinfo;
3869 : 90936 : }
3870 : :
3871 : : /* Not found in ec_sources; search derived clauses */
3872 : 84654 : return ec_search_derived_clause_for_ems(root, ec, leftem, rightem,
3873 : 42327 : parent_ec);
3874 : 42604 : }
3875 : :
3876 : : /*
3877 : : * ec_search_derived_clause_for_ems
3878 : : * Search for an existing derived clause between two EquivalenceMembers.
3879 : : *
3880 : : * If the number of derived clauses exceeds a threshold, switch to hash table
3881 : : * lookup; otherwise, scan ec_derives_list linearly.
3882 : : *
3883 : : * Clauses involving constants are looked up by passing the non-constant EM
3884 : : * as leftem and setting rightem to NULL. In that case, we expect to find a
3885 : : * clause with a constant on the RHS.
3886 : : *
3887 : : * While searching the list, we compare each given EM with both sides of each
3888 : : * clause. But for hash table lookups, we construct a canonicalized key and
3889 : : * perform a single lookup.
3890 : : */
3891 : : static RestrictInfo *
3892 : 42328 : ec_search_derived_clause_for_ems(PlannerInfo *root, EquivalenceClass *ec,
3893 : : EquivalenceMember *leftem,
3894 : : EquivalenceMember *rightem,
3895 : : EquivalenceClass *parent_ec)
3896 : : {
3897 : : /* Switch to using hash lookup when list grows "too long". */
3898 [ + - + - ]: 42328 : if (!ec->ec_derives_hash &&
3899 : 42328 : list_length(ec->ec_derives_list) >= EC_DERIVES_HASH_THRESHOLD)
3900 : 0 : ec_build_derives_hash(root, ec);
3901 : :
3902 : : /* Perform hash table lookup if available */
3903 [ - + ]: 42328 : if (ec->ec_derives_hash)
3904 : : {
3905 : 0 : ECDerivesKey key;
3906 : 0 : RestrictInfo *rinfo;
3907 : 0 : ECDerivesEntry *entry;
3908 : :
3909 : 0 : fill_ec_derives_key(&key, leftem, rightem, parent_ec);
3910 : 0 : entry = derives_lookup(ec->ec_derives_hash, key);
3911 [ # # ]: 0 : if (entry)
3912 : : {
3913 : 0 : rinfo = entry->rinfo;
3914 [ # # ]: 0 : Assert(rinfo);
3915 [ # # # # ]: 0 : Assert(rightem || rinfo->right_em->em_is_const);
3916 : 0 : return rinfo;
3917 : : }
3918 [ # # ]: 0 : }
3919 : : else
3920 : : {
3921 : : /* Fallback to linear search over ec_derives_list */
3922 [ + + + + : 101485 : foreach_node(RestrictInfo, rinfo, ec->ec_derives_list)
+ + + + +
+ + + ]
3923 : : {
3924 : : /* Handle special case: lookup by non-const EM alone */
3925 [ + + - + ]: 50995 : if (!rightem &&
3926 : 1 : rinfo->left_em == leftem)
3927 : : {
3928 [ + - ]: 1 : Assert(rinfo->right_em->em_is_const);
3929 : 1 : return rinfo;
3930 : : }
3931 [ + + ]: 50994 : if (rinfo->left_em == leftem &&
3932 [ + + + + ]: 17478 : rinfo->right_em == rightem &&
3933 : 15526 : rinfo->parent_ec == parent_ec)
3934 : 15524 : return rinfo;
3935 [ + + ]: 35470 : if (rinfo->left_em == rightem &&
3936 [ + + + - ]: 19989 : rinfo->right_em == leftem &&
3937 : 18641 : rinfo->parent_ec == parent_ec)
3938 : 18641 : return rinfo;
3939 : 24991 : }
3940 : : }
3941 : :
3942 : 8162 : return NULL;
3943 : 42328 : }
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