Branch data Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * dependencies.c
4 : : * POSTGRES functional dependencies
5 : : *
6 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : : * Portions Copyright (c) 1994, Regents of the University of California
8 : : *
9 : : * IDENTIFICATION
10 : : * src/backend/statistics/dependencies.c
11 : : *
12 : : *-------------------------------------------------------------------------
13 : : */
14 : : #include "postgres.h"
15 : :
16 : : #include "access/htup_details.h"
17 : : #include "catalog/pg_statistic_ext.h"
18 : : #include "catalog/pg_statistic_ext_data.h"
19 : : #include "nodes/nodeFuncs.h"
20 : : #include "optimizer/clauses.h"
21 : : #include "optimizer/optimizer.h"
22 : : #include "parser/parsetree.h"
23 : : #include "statistics/extended_stats_internal.h"
24 : : #include "utils/fmgroids.h"
25 : : #include "utils/lsyscache.h"
26 : : #include "utils/memutils.h"
27 : : #include "utils/selfuncs.h"
28 : : #include "utils/syscache.h"
29 : : #include "utils/typcache.h"
30 : :
31 : : /* size of the struct header fields (magic, type, ndeps) */
32 : : #define SizeOfHeader (3 * sizeof(uint32))
33 : :
34 : : /* size of a serialized dependency (degree, natts, atts) */
35 : : #define SizeOfItem(natts) \
36 : : (sizeof(double) + sizeof(AttrNumber) * (1 + (natts)))
37 : :
38 : : /* minimal size of a dependency (with two attributes) */
39 : : #define MinSizeOfItem SizeOfItem(2)
40 : :
41 : : /* minimal size of dependencies, when all deps are minimal */
42 : : #define MinSizeOfItems(ndeps) \
43 : : (SizeOfHeader + (ndeps) * MinSizeOfItem)
44 : :
45 : : /*
46 : : * Internal state for DependencyGenerator of dependencies. Dependencies are similar to
47 : : * k-permutations of n elements, except that the order does not matter for the
48 : : * first (k-1) elements. That is, (a,b=>c) and (b,a=>c) are equivalent.
49 : : */
50 : : typedef struct DependencyGeneratorData
51 : : {
52 : : int k; /* size of the dependency */
53 : : int n; /* number of possible attributes */
54 : : int current; /* next dependency to return (index) */
55 : : AttrNumber ndependencies; /* number of dependencies generated */
56 : : AttrNumber *dependencies; /* array of pre-generated dependencies */
57 : : } DependencyGeneratorData;
58 : :
59 : : typedef DependencyGeneratorData *DependencyGenerator;
60 : :
61 : : static void generate_dependencies_recurse(DependencyGenerator state,
62 : : int index, AttrNumber start, AttrNumber *current);
63 : : static void generate_dependencies(DependencyGenerator state);
64 : : static DependencyGenerator DependencyGenerator_init(int n, int k);
65 : : static void DependencyGenerator_free(DependencyGenerator state);
66 : : static AttrNumber *DependencyGenerator_next(DependencyGenerator state);
67 : : static double dependency_degree(StatsBuildData *data, int k, AttrNumber *dependency);
68 : : static bool dependency_is_fully_matched(MVDependency *dependency,
69 : : Bitmapset *attnums);
70 : : static bool dependency_is_compatible_clause(Node *clause, Index relid,
71 : : AttrNumber *attnum);
72 : : static bool dependency_is_compatible_expression(Node *clause, Index relid,
73 : : List *statlist, Node **expr);
74 : : static MVDependency *find_strongest_dependency(MVDependencies **dependencies,
75 : : int ndependencies, Bitmapset *attnums);
76 : : static Selectivity clauselist_apply_dependencies(PlannerInfo *root, List *clauses,
77 : : int varRelid, JoinType jointype,
78 : : SpecialJoinInfo *sjinfo,
79 : : MVDependency **dependencies,
80 : : int ndependencies,
81 : : AttrNumber *list_attnums,
82 : : Bitmapset **estimatedclauses);
83 : :
84 : : static void
85 : 167 : generate_dependencies_recurse(DependencyGenerator state, int index,
86 : : AttrNumber start, AttrNumber *current)
87 : : {
88 : : /*
89 : : * The generator handles the first (k-1) elements differently from the
90 : : * last element.
91 : : */
92 [ + + ]: 167 : if (index < (state->k - 1))
93 : : {
94 : 73 : AttrNumber i;
95 : :
96 : : /*
97 : : * The first (k-1) values have to be in ascending order, which we
98 : : * generate recursively.
99 : : */
100 : :
101 [ + + ]: 205 : for (i = start; i < state->n; i++)
102 : : {
103 : 132 : current[index] = i;
104 : 132 : generate_dependencies_recurse(state, (index + 1), (i + 1), current);
105 : 132 : }
106 : 73 : }
107 : : else
108 : : {
109 : 94 : int i;
110 : :
111 : : /*
112 : : * the last element is the implied value, which does not respect the
113 : : * ascending order. We just need to check that the value is not in the
114 : : * first (k-1) elements.
115 : : */
116 : :
117 [ + + ]: 358 : for (i = 0; i < state->n; i++)
118 : : {
119 : 264 : int j;
120 : 264 : bool match = false;
121 : :
122 : 264 : current[index] = i;
123 : :
124 [ + + ]: 482 : for (j = 0; j < index; j++)
125 : : {
126 [ + + ]: 350 : if (current[j] == i)
127 : : {
128 : 132 : match = true;
129 : 132 : break;
130 : : }
131 : 218 : }
132 : :
133 : : /*
134 : : * If the value is not found in the first part of the dependency,
135 : : * we're done.
136 : : */
137 [ + + ]: 264 : if (!match)
138 : : {
139 : 264 : state->dependencies = (AttrNumber *) repalloc(state->dependencies,
140 : 132 : state->k * (state->ndependencies + 1) * sizeof(AttrNumber));
141 : 132 : memcpy(&state->dependencies[(state->k * state->ndependencies)],
142 : : current, state->k * sizeof(AttrNumber));
143 : 132 : state->ndependencies++;
144 : 132 : }
145 : 264 : }
146 : 94 : }
147 : 167 : }
148 : :
149 : : /* generate all dependencies (k-permutations of n elements) */
150 : : static void
151 : 35 : generate_dependencies(DependencyGenerator state)
152 : : {
153 : 35 : AttrNumber *current = palloc0_array(AttrNumber, state->k);
154 : :
155 : 35 : generate_dependencies_recurse(state, 0, 0, current);
156 : :
157 : 35 : pfree(current);
158 : 35 : }
159 : :
160 : : /*
161 : : * initialize the DependencyGenerator of variations, and prebuild the variations
162 : : *
163 : : * This pre-builds all the variations. We could also generate them in
164 : : * DependencyGenerator_next(), but this seems simpler.
165 : : */
166 : : static DependencyGenerator
167 : 35 : DependencyGenerator_init(int n, int k)
168 : : {
169 : 35 : DependencyGenerator state;
170 : :
171 [ + - ]: 35 : Assert((n >= k) && (k > 0));
172 : :
173 : : /* allocate the DependencyGenerator state */
174 : 35 : state = palloc0_object(DependencyGeneratorData);
175 : 35 : state->dependencies = palloc_array(AttrNumber, k);
176 : :
177 : 35 : state->ndependencies = 0;
178 : 35 : state->current = 0;
179 : 35 : state->k = k;
180 : 35 : state->n = n;
181 : :
182 : : /* now actually pre-generate all the variations */
183 : 35 : generate_dependencies(state);
184 : :
185 : 70 : return state;
186 : 35 : }
187 : :
188 : : /* free the DependencyGenerator state */
189 : : static void
190 : 35 : DependencyGenerator_free(DependencyGenerator state)
191 : : {
192 : 35 : pfree(state->dependencies);
193 : 35 : pfree(state);
194 : 35 : }
195 : :
196 : : /* generate next combination */
197 : : static AttrNumber *
198 : 167 : DependencyGenerator_next(DependencyGenerator state)
199 : : {
200 [ + + ]: 167 : if (state->current == state->ndependencies)
201 : 35 : return NULL;
202 : :
203 : 132 : return &state->dependencies[state->k * state->current++];
204 : 167 : }
205 : :
206 : :
207 : : /*
208 : : * validates functional dependency on the data
209 : : *
210 : : * An actual work horse of detecting functional dependencies. Given a variation
211 : : * of k attributes, it checks that the first (k-1) are sufficient to determine
212 : : * the last one.
213 : : */
214 : : static double
215 : 132 : dependency_degree(StatsBuildData *data, int k, AttrNumber *dependency)
216 : : {
217 : 132 : int i,
218 : : nitems;
219 : 132 : MultiSortSupport mss;
220 : 132 : SortItem *items;
221 : 132 : AttrNumber *attnums_dep;
222 : :
223 : : /* counters valid within a group */
224 : 132 : int group_size = 0;
225 : 132 : int n_violations = 0;
226 : :
227 : : /* total number of rows supporting (consistent with) the dependency */
228 : 132 : int n_supporting_rows = 0;
229 : :
230 : : /* Make sure we have at least two input attributes. */
231 [ + - ]: 132 : Assert(k >= 2);
232 : :
233 : : /* sort info for all attributes columns */
234 : 132 : mss = multi_sort_init(k);
235 : :
236 : : /*
237 : : * Translate the array of indexes to regular attnums for the dependency
238 : : * (we will need this to identify the columns in StatsBuildData).
239 : : */
240 : 132 : attnums_dep = palloc_array(AttrNumber, k);
241 [ + + ]: 440 : for (i = 0; i < k; i++)
242 : 308 : attnums_dep[i] = data->attnums[dependency[i]];
243 : :
244 : : /*
245 : : * Verify the dependency (a,b,...)->z, using a rather simple algorithm:
246 : : *
247 : : * (a) sort the data lexicographically
248 : : *
249 : : * (b) split the data into groups by first (k-1) columns
250 : : *
251 : : * (c) for each group count different values in the last column
252 : : *
253 : : * We use the column data types' default sort operators and collations;
254 : : * perhaps at some point it'd be worth using column-specific collations?
255 : : */
256 : :
257 : : /* prepare the sort function for the dimensions */
258 [ + + ]: 440 : for (i = 0; i < k; i++)
259 : : {
260 : 308 : VacAttrStats *colstat = data->stats[dependency[i]];
261 : 308 : TypeCacheEntry *type;
262 : :
263 : 308 : type = lookup_type_cache(colstat->attrtypid, TYPECACHE_LT_OPR);
264 [ + - ]: 308 : if (type->lt_opr == InvalidOid) /* shouldn't happen */
265 [ # # # # ]: 0 : elog(ERROR, "cache lookup failed for ordering operator for type %u",
266 : : colstat->attrtypid);
267 : :
268 : : /* prepare the sort function for this dimension */
269 : 308 : multi_sort_add_dimension(mss, i, type->lt_opr, colstat->attrcollid);
270 : 308 : }
271 : :
272 : : /*
273 : : * build an array of SortItem(s) sorted using the multi-sort support
274 : : *
275 : : * XXX This relies on all stats entries pointing to the same tuple
276 : : * descriptor. For now that assumption holds, but it might change in the
277 : : * future for example if we support statistics on multiple tables.
278 : : */
279 : 132 : items = build_sorted_items(data, &nitems, mss, k, attnums_dep);
280 : :
281 : : /*
282 : : * Walk through the sorted array, split it into rows according to the
283 : : * first (k-1) columns. If there's a single value in the last column, we
284 : : * count the group as 'supporting' the functional dependency. Otherwise we
285 : : * count it as contradicting.
286 : : */
287 : :
288 : : /* start with the first row forming a group */
289 : 132 : group_size = 1;
290 : :
291 : : /* loop 1 beyond the end of the array so that we count the final group */
292 [ + + ]: 251083 : for (i = 1; i <= nitems; i++)
293 : : {
294 : : /*
295 : : * Check if the group ended, which may be either because we processed
296 : : * all the items (i==nitems), or because the i-th item is not equal to
297 : : * the preceding one.
298 : : */
299 [ + + + + ]: 250951 : if (i == nitems ||
300 : 250819 : multi_sort_compare_dims(0, k - 2, &items[i - 1], &items[i], mss) != 0)
301 : : {
302 : : /*
303 : : * If no violations were found in the group then track the rows of
304 : : * the group as supporting the functional dependency.
305 : : */
306 [ + + ]: 5502 : if (n_violations == 0)
307 : 3379 : n_supporting_rows += group_size;
308 : :
309 : : /* Reset counters for the new group */
310 : 5502 : n_violations = 0;
311 : 5502 : group_size = 1;
312 : 5502 : continue;
313 : : }
314 : : /* first columns match, but the last one does not (so contradicting) */
315 [ + + ]: 245449 : else if (multi_sort_compare_dim(k - 1, &items[i - 1], &items[i], mss) != 0)
316 : 10031 : n_violations++;
317 : :
318 : 245449 : group_size++;
319 : 245449 : }
320 : :
321 : : /* Compute the 'degree of validity' as (supporting/total). */
322 : 264 : return (n_supporting_rows * 1.0 / data->numrows);
323 : 132 : }
324 : :
325 : : /*
326 : : * detects functional dependencies between groups of columns
327 : : *
328 : : * Generates all possible subsets of columns (variations) and computes
329 : : * the degree of validity for each one. For example when creating statistics
330 : : * on three columns (a,b,c) there are 9 possible dependencies
331 : : *
332 : : * two columns three columns
333 : : * ----------- -------------
334 : : * (a) -> b (a,b) -> c
335 : : * (a) -> c (a,c) -> b
336 : : * (b) -> a (b,c) -> a
337 : : * (b) -> c
338 : : * (c) -> a
339 : : * (c) -> b
340 : : */
341 : : MVDependencies *
342 : 25 : statext_dependencies_build(StatsBuildData *data)
343 : : {
344 : 25 : int i,
345 : : k;
346 : :
347 : : /* result */
348 : 25 : MVDependencies *dependencies = NULL;
349 : 25 : MemoryContext cxt;
350 : :
351 [ + - ]: 25 : Assert(data->nattnums >= 2);
352 : :
353 : : /* tracks memory allocated by dependency_degree calls */
354 : 25 : cxt = AllocSetContextCreate(CurrentMemoryContext,
355 : : "dependency_degree cxt",
356 : : ALLOCSET_DEFAULT_SIZES);
357 : :
358 : : /*
359 : : * We'll try build functional dependencies starting from the smallest ones
360 : : * covering just 2 columns, to the largest ones, covering all columns
361 : : * included in the statistics object. We start from the smallest ones
362 : : * because we want to be able to skip already implied ones.
363 : : */
364 [ + + ]: 60 : for (k = 2; k <= data->nattnums; k++)
365 : : {
366 : 35 : AttrNumber *dependency; /* array with k elements */
367 : :
368 : : /* prepare a DependencyGenerator of variation */
369 : 35 : DependencyGenerator DependencyGenerator = DependencyGenerator_init(data->nattnums, k);
370 : :
371 : : /* generate all possible variations of k values (out of n) */
372 [ + + ]: 167 : while ((dependency = DependencyGenerator_next(DependencyGenerator)))
373 : : {
374 : 132 : double degree;
375 : 132 : MVDependency *d;
376 : 132 : MemoryContext oldcxt;
377 : :
378 : : /* release memory used by dependency degree calculation */
379 : 132 : oldcxt = MemoryContextSwitchTo(cxt);
380 : :
381 : : /* compute how valid the dependency seems */
382 : 132 : degree = dependency_degree(data, k, dependency);
383 : :
384 : 132 : MemoryContextSwitchTo(oldcxt);
385 : 132 : MemoryContextReset(cxt);
386 : :
387 : : /*
388 : : * if the dependency seems entirely invalid, don't store it
389 : : */
390 [ + + ]: 132 : if (degree == 0.0)
391 : 43 : continue;
392 : :
393 : 89 : d = (MVDependency *) palloc0(offsetof(MVDependency, attributes)
394 : 89 : + k * sizeof(AttrNumber));
395 : :
396 : : /* copy the dependency (and keep the indexes into stxkeys) */
397 : 89 : d->degree = degree;
398 : 89 : d->nattributes = k;
399 [ + + ]: 299 : for (i = 0; i < k; i++)
400 : 210 : d->attributes[i] = data->attnums[dependency[i]];
401 : :
402 : : /* initialize the list of dependencies */
403 [ + + ]: 89 : if (dependencies == NULL)
404 : : {
405 : 22 : dependencies = palloc0_object(MVDependencies);
406 : :
407 : 22 : dependencies->magic = STATS_DEPS_MAGIC;
408 : 22 : dependencies->type = STATS_DEPS_TYPE_BASIC;
409 : 22 : dependencies->ndeps = 0;
410 : 22 : }
411 : :
412 : 89 : dependencies->ndeps++;
413 : 178 : dependencies = (MVDependencies *) repalloc(dependencies,
414 : : offsetof(MVDependencies, deps)
415 : 89 : + dependencies->ndeps * sizeof(MVDependency *));
416 : :
417 : 89 : dependencies->deps[dependencies->ndeps - 1] = d;
418 [ - + + ]: 132 : }
419 : :
420 : : /*
421 : : * we're done with variations of k elements, so free the
422 : : * DependencyGenerator
423 : : */
424 : 35 : DependencyGenerator_free(DependencyGenerator);
425 : 35 : }
426 : :
427 : 25 : MemoryContextDelete(cxt);
428 : :
429 : 50 : return dependencies;
430 : 25 : }
431 : :
432 : :
433 : : /*
434 : : * Serialize list of dependencies into a bytea value.
435 : : */
436 : : bytea *
437 : 29 : statext_dependencies_serialize(MVDependencies *dependencies)
438 : : {
439 : 29 : int i;
440 : 29 : bytea *output;
441 : 29 : char *tmp;
442 : 29 : Size len;
443 : :
444 : : /* we need to store ndeps, with a number of attributes for each one */
445 : 29 : len = VARHDRSZ + SizeOfHeader;
446 : :
447 : : /* and also include space for the actual attribute numbers and degrees */
448 [ + + ]: 134 : for (i = 0; i < dependencies->ndeps; i++)
449 : 105 : len += SizeOfItem(dependencies->deps[i]->nattributes);
450 : :
451 : 29 : output = (bytea *) palloc0(len);
452 : 29 : SET_VARSIZE(output, len);
453 : :
454 : 29 : tmp = VARDATA(output);
455 : :
456 : : /* Store the base struct values (magic, type, ndeps) */
457 : 29 : memcpy(tmp, &dependencies->magic, sizeof(uint32));
458 : 29 : tmp += sizeof(uint32);
459 : 29 : memcpy(tmp, &dependencies->type, sizeof(uint32));
460 : 29 : tmp += sizeof(uint32);
461 : 29 : memcpy(tmp, &dependencies->ndeps, sizeof(uint32));
462 : 29 : tmp += sizeof(uint32);
463 : :
464 : : /* store number of attributes and attribute numbers for each dependency */
465 [ + + ]: 134 : for (i = 0; i < dependencies->ndeps; i++)
466 : : {
467 : 105 : MVDependency *d = dependencies->deps[i];
468 : :
469 : 105 : memcpy(tmp, &d->degree, sizeof(double));
470 : 105 : tmp += sizeof(double);
471 : :
472 : 105 : memcpy(tmp, &d->nattributes, sizeof(AttrNumber));
473 : 105 : tmp += sizeof(AttrNumber);
474 : :
475 : 105 : memcpy(tmp, d->attributes, sizeof(AttrNumber) * d->nattributes);
476 : 105 : tmp += sizeof(AttrNumber) * d->nattributes;
477 : :
478 : : /* protect against overflow */
479 [ + - ]: 105 : Assert(tmp <= ((char *) output + len));
480 : 105 : }
481 : :
482 : : /* make sure we've produced exactly the right amount of data */
483 [ + - ]: 29 : Assert(tmp == ((char *) output + len));
484 : :
485 : 58 : return output;
486 : 29 : }
487 : :
488 : : /*
489 : : * Reads serialized dependencies into MVDependencies structure.
490 : : */
491 : : MVDependencies *
492 : 276 : statext_dependencies_deserialize(bytea *data)
493 : : {
494 : 276 : int i;
495 : 276 : Size min_expected_size;
496 : 276 : MVDependencies *dependencies;
497 : 276 : char *tmp;
498 : :
499 [ + - ]: 276 : if (data == NULL)
500 : 0 : return NULL;
501 : :
502 [ + - ]: 276 : if (VARSIZE_ANY_EXHDR(data) < SizeOfHeader)
503 [ # # # # ]: 0 : elog(ERROR, "invalid MVDependencies size %zu (expected at least %zu)",
504 : : VARSIZE_ANY_EXHDR(data), SizeOfHeader);
505 : :
506 : : /* read the MVDependencies header */
507 : 276 : dependencies = palloc0_object(MVDependencies);
508 : :
509 : : /* initialize pointer to the data part (skip the varlena header) */
510 : 276 : tmp = VARDATA_ANY(data);
511 : :
512 : : /* read the header fields and perform basic sanity checks */
513 : 276 : memcpy(&dependencies->magic, tmp, sizeof(uint32));
514 : 276 : tmp += sizeof(uint32);
515 : 276 : memcpy(&dependencies->type, tmp, sizeof(uint32));
516 : 276 : tmp += sizeof(uint32);
517 : 276 : memcpy(&dependencies->ndeps, tmp, sizeof(uint32));
518 : 276 : tmp += sizeof(uint32);
519 : :
520 [ + - ]: 276 : if (dependencies->magic != STATS_DEPS_MAGIC)
521 [ # # # # ]: 0 : elog(ERROR, "invalid dependency magic %d (expected %d)",
522 : : dependencies->magic, STATS_DEPS_MAGIC);
523 : :
524 [ + - ]: 276 : if (dependencies->type != STATS_DEPS_TYPE_BASIC)
525 [ # # # # ]: 0 : elog(ERROR, "invalid dependency type %d (expected %d)",
526 : : dependencies->type, STATS_DEPS_TYPE_BASIC);
527 : :
528 [ + - ]: 276 : if (dependencies->ndeps == 0)
529 [ # # # # ]: 0 : elog(ERROR, "invalid zero-length item array in MVDependencies");
530 : :
531 : : /* what minimum bytea size do we expect for those parameters */
532 : 276 : min_expected_size = SizeOfItem(dependencies->ndeps);
533 : :
534 [ + - ]: 276 : if (VARSIZE_ANY_EXHDR(data) < min_expected_size)
535 [ # # # # ]: 0 : elog(ERROR, "invalid dependencies size %zu (expected at least %zu)",
536 : : VARSIZE_ANY_EXHDR(data), min_expected_size);
537 : :
538 : : /* allocate space for the MCV items */
539 : 552 : dependencies = repalloc(dependencies, offsetof(MVDependencies, deps)
540 : 276 : + (dependencies->ndeps * sizeof(MVDependency *)));
541 : :
542 [ + + ]: 1617 : for (i = 0; i < dependencies->ndeps; i++)
543 : : {
544 : 1341 : double degree;
545 : 1341 : AttrNumber k;
546 : 1341 : MVDependency *d;
547 : :
548 : : /* degree of validity */
549 : 1341 : memcpy(°ree, tmp, sizeof(double));
550 : 1341 : tmp += sizeof(double);
551 : :
552 : : /* number of attributes */
553 : 1341 : memcpy(&k, tmp, sizeof(AttrNumber));
554 : 1341 : tmp += sizeof(AttrNumber);
555 : :
556 : : /* is the number of attributes valid? */
557 [ + - ]: 1341 : Assert((k >= 2) && (k <= STATS_MAX_DIMENSIONS));
558 : :
559 : : /* now that we know the number of attributes, allocate the dependency */
560 : 1341 : d = (MVDependency *) palloc0(offsetof(MVDependency, attributes)
561 : 1341 : + (k * sizeof(AttrNumber)));
562 : :
563 : 1341 : d->degree = degree;
564 : 1341 : d->nattributes = k;
565 : :
566 : : /* copy attribute numbers */
567 : 1341 : memcpy(d->attributes, tmp, sizeof(AttrNumber) * d->nattributes);
568 : 1341 : tmp += sizeof(AttrNumber) * d->nattributes;
569 : :
570 : 1341 : dependencies->deps[i] = d;
571 : :
572 : : /* still within the bytea */
573 [ - + ]: 1341 : Assert(tmp <= ((char *) data + VARSIZE_ANY(data)));
574 : 1341 : }
575 : :
576 : : /* we should have consumed the whole bytea exactly */
577 [ + - ]: 276 : Assert(tmp == ((char *) data + VARSIZE_ANY(data)));
578 : :
579 : 276 : return dependencies;
580 : 276 : }
581 : :
582 : : /*
583 : : * Free allocations of a MVDependencies.
584 : : */
585 : : void
586 : 0 : statext_dependencies_free(MVDependencies *dependencies)
587 : : {
588 [ # # ]: 0 : for (int i = 0; i < dependencies->ndeps; i++)
589 : 0 : pfree(dependencies->deps[i]);
590 : 0 : pfree(dependencies);
591 : 0 : }
592 : :
593 : : /*
594 : : * Validate a set of MVDependencies against the extended statistics object
595 : : * definition.
596 : : *
597 : : * Every MVDependencies must be checked to ensure that the attnums in the
598 : : * attributes list correspond to attnums/expressions defined by the
599 : : * extended statistics object.
600 : : *
601 : : * Positive attnums are attributes which must be found in the stxkeys, while
602 : : * negative attnums correspond to an expression number, no attribute number
603 : : * can be below (0 - numexprs).
604 : : */
605 : : bool
606 : 0 : statext_dependencies_validate(const MVDependencies *dependencies,
607 : : const int2vector *stxkeys,
608 : : int numexprs, int elevel)
609 : : {
610 : 0 : int attnum_expr_lowbound = 0 - numexprs;
611 : :
612 : : /* Scan through each dependency entry */
613 [ # # # # ]: 0 : for (int i = 0; i < dependencies->ndeps; i++)
614 : : {
615 : 0 : const MVDependency *dep = dependencies->deps[i];
616 : :
617 : : /*
618 : : * Cross-check each attribute in a dependency entry with the extended
619 : : * stats object definition.
620 : : */
621 [ # # # # ]: 0 : for (int j = 0; j < dep->nattributes; j++)
622 : : {
623 : 0 : AttrNumber attnum = dep->attributes[j];
624 : 0 : bool ok = false;
625 : :
626 [ # # ]: 0 : if (attnum > 0)
627 : : {
628 : : /* attribute number in stxkeys */
629 [ # # ]: 0 : for (int k = 0; k < stxkeys->dim1; k++)
630 : : {
631 [ # # ]: 0 : if (attnum == stxkeys->values[k])
632 : : {
633 : 0 : ok = true;
634 : 0 : break;
635 : : }
636 : 0 : }
637 : 0 : }
638 [ # # # # ]: 0 : else if ((attnum < 0) && (attnum >= attnum_expr_lowbound))
639 : : {
640 : : /* attribute number for an expression */
641 : 0 : ok = true;
642 : 0 : }
643 : :
644 [ # # ]: 0 : if (!ok)
645 : : {
646 [ # # # # : 0 : ereport(elevel,
# # # # #
# ]
647 : : (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
648 : : errmsg("could not validate \"%s\" object: invalid attribute number %d found",
649 : : "pg_dependencies", attnum)));
650 : 0 : return false;
651 : : }
652 [ # # ]: 0 : }
653 [ # # ]: 0 : }
654 : :
655 : 0 : return true;
656 : 0 : }
657 : :
658 : : /*
659 : : * dependency_is_fully_matched
660 : : * checks that a functional dependency is fully matched given clauses on
661 : : * attributes (assuming the clauses are suitable equality clauses)
662 : : */
663 : : static bool
664 : 1026 : dependency_is_fully_matched(MVDependency *dependency, Bitmapset *attnums)
665 : : {
666 : 1026 : int j;
667 : :
668 : : /*
669 : : * Check that the dependency actually is fully covered by clauses. We have
670 : : * to translate all attribute numbers, as those are referenced
671 : : */
672 [ + + ]: 2607 : for (j = 0; j < dependency->nattributes; j++)
673 : : {
674 : 2093 : int attnum = dependency->attributes[j];
675 : :
676 [ + + ]: 2093 : if (!bms_is_member(attnum, attnums))
677 : 512 : return false;
678 [ + + ]: 2093 : }
679 : :
680 : 514 : return true;
681 : 1026 : }
682 : :
683 : : /*
684 : : * statext_dependencies_load
685 : : * Load the functional dependencies for the indicated pg_statistic_ext tuple
686 : : */
687 : : MVDependencies *
688 : 268 : statext_dependencies_load(Oid mvoid, bool inh)
689 : : {
690 : 268 : MVDependencies *result;
691 : 268 : bool isnull;
692 : 268 : Datum deps;
693 : 268 : HeapTuple htup;
694 : :
695 : 268 : htup = SearchSysCache2(STATEXTDATASTXOID,
696 : 268 : ObjectIdGetDatum(mvoid),
697 : 268 : BoolGetDatum(inh));
698 [ + - ]: 268 : if (!HeapTupleIsValid(htup))
699 [ # # # # ]: 0 : elog(ERROR, "cache lookup failed for statistics object %u", mvoid);
700 : :
701 : 268 : deps = SysCacheGetAttr(STATEXTDATASTXOID, htup,
702 : : Anum_pg_statistic_ext_data_stxddependencies, &isnull);
703 [ + - ]: 268 : if (isnull)
704 [ # # # # ]: 0 : elog(ERROR,
705 : : "requested statistics kind \"%c\" is not yet built for statistics object %u",
706 : : STATS_EXT_DEPENDENCIES, mvoid);
707 : :
708 : 268 : result = statext_dependencies_deserialize(DatumGetByteaPP(deps));
709 : :
710 : 268 : ReleaseSysCache(htup);
711 : :
712 : 536 : return result;
713 : 268 : }
714 : :
715 : : /*
716 : : * dependency_is_compatible_clause
717 : : * Determines if the clause is compatible with functional dependencies
718 : : *
719 : : * Only clauses that have the form of equality to a pseudoconstant, or can be
720 : : * interpreted that way, are currently accepted. Furthermore the variable
721 : : * part of the clause must be a simple Var belonging to the specified
722 : : * relation, whose attribute number we return in *attnum on success.
723 : : */
724 : : static bool
725 : 660 : dependency_is_compatible_clause(Node *clause, Index relid, AttrNumber *attnum)
726 : : {
727 : 660 : Var *var;
728 : 660 : Node *clause_expr;
729 : :
730 [ + + ]: 660 : if (IsA(clause, RestrictInfo))
731 : : {
732 : 640 : RestrictInfo *rinfo = (RestrictInfo *) clause;
733 : :
734 : : /* Pseudoconstants are not interesting (they couldn't contain a Var) */
735 [ + + ]: 640 : if (rinfo->pseudoconstant)
736 : 1 : return false;
737 : :
738 : : /* Clauses referencing multiple, or no, varnos are incompatible */
739 [ - + ]: 639 : if (bms_membership(rinfo->clause_relids) != BMS_SINGLETON)
740 : 0 : return false;
741 : :
742 : 639 : clause = (Node *) rinfo->clause;
743 [ + + ]: 640 : }
744 : :
745 [ + + ]: 659 : if (is_opclause(clause))
746 : : {
747 : : /* If it's an opclause, check for Var = Const or Const = Var. */
748 : 241 : OpExpr *expr = (OpExpr *) clause;
749 : :
750 : : /* Only expressions with two arguments are candidates. */
751 [ - + ]: 241 : if (list_length(expr->args) != 2)
752 : 0 : return false;
753 : :
754 : : /* Make sure non-selected argument is a pseudoconstant. */
755 [ + - ]: 241 : if (is_pseudo_constant_clause(lsecond(expr->args)))
756 : 241 : clause_expr = linitial(expr->args);
757 [ # # ]: 0 : else if (is_pseudo_constant_clause(linitial(expr->args)))
758 : 0 : clause_expr = lsecond(expr->args);
759 : : else
760 : 0 : return false;
761 : :
762 : : /*
763 : : * If it's not an "=" operator, just ignore the clause, as it's not
764 : : * compatible with functional dependencies.
765 : : *
766 : : * This uses the function for estimating selectivity, not the operator
767 : : * directly (a bit awkward, but well ...).
768 : : *
769 : : * XXX this is pretty dubious; probably it'd be better to check btree
770 : : * or hash opclass membership, so as not to be fooled by custom
771 : : * selectivity functions, and to be more consistent with decisions
772 : : * elsewhere in the planner.
773 : : */
774 [ + + ]: 241 : if (get_oprrest(expr->opno) != F_EQSEL)
775 : 6 : return false;
776 : :
777 : : /* OK to proceed with checking "var" */
778 [ + + ]: 241 : }
779 [ + + ]: 418 : else if (IsA(clause, ScalarArrayOpExpr))
780 : : {
781 : : /* If it's a scalar array operator, check for Var IN Const. */
782 : 406 : ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) clause;
783 : :
784 : : /*
785 : : * Reject ALL() variant, we only care about ANY/IN.
786 : : *
787 : : * XXX Maybe we should check if all the values are the same, and allow
788 : : * ALL in that case? Doesn't seem very practical, though.
789 : : */
790 [ + + ]: 406 : if (!expr->useOr)
791 : 6 : return false;
792 : :
793 : : /* Only expressions with two arguments are candidates. */
794 [ - + ]: 400 : if (list_length(expr->args) != 2)
795 : 0 : return false;
796 : :
797 : : /*
798 : : * We know it's always (Var IN Const), so we assume the var is the
799 : : * first argument, and pseudoconstant is the second one.
800 : : */
801 [ + - ]: 400 : if (!is_pseudo_constant_clause(lsecond(expr->args)))
802 : 0 : return false;
803 : :
804 : 400 : clause_expr = linitial(expr->args);
805 : :
806 : : /*
807 : : * If it's not an "=" operator, just ignore the clause, as it's not
808 : : * compatible with functional dependencies. The operator is identified
809 : : * simply by looking at which function it uses to estimate
810 : : * selectivity. That's a bit strange, but it's what other similar
811 : : * places do.
812 : : */
813 [ + + ]: 400 : if (get_oprrest(expr->opno) != F_EQSEL)
814 : 30 : return false;
815 : :
816 : : /* OK to proceed with checking "var" */
817 [ + + ]: 406 : }
818 [ + - ]: 12 : else if (is_orclause(clause))
819 : : {
820 : 12 : BoolExpr *bool_expr = (BoolExpr *) clause;
821 : 12 : ListCell *lc;
822 : :
823 : : /* start with no attribute number */
824 : 12 : *attnum = InvalidAttrNumber;
825 : :
826 [ + - + + : 32 : foreach(lc, bool_expr->args)
+ + + + ]
827 : : {
828 : 20 : AttrNumber clause_attnum;
829 : :
830 : : /*
831 : : * Had we found incompatible clause in the arguments, treat the
832 : : * whole clause as incompatible.
833 : : */
834 [ + + + + ]: 40 : if (!dependency_is_compatible_clause((Node *) lfirst(lc),
835 : 20 : relid, &clause_attnum))
836 : 6 : return false;
837 : :
838 [ + + ]: 14 : if (*attnum == InvalidAttrNumber)
839 : 6 : *attnum = clause_attnum;
840 : :
841 : : /* ensure all the variables are the same (same attnum) */
842 [ + + ]: 14 : if (*attnum != clause_attnum)
843 : 1 : return false;
844 [ + + ]: 20 : }
845 : :
846 : : /* the Var is already checked by the recursive call */
847 : 5 : return true;
848 : 12 : }
849 [ # # ]: 0 : else if (is_notclause(clause))
850 : : {
851 : : /*
852 : : * "NOT x" can be interpreted as "x = false", so get the argument and
853 : : * proceed with seeing if it's a suitable Var.
854 : : */
855 : 0 : clause_expr = (Node *) get_notclausearg(clause);
856 : 0 : }
857 : : else
858 : : {
859 : : /*
860 : : * A boolean expression "x" can be interpreted as "x = true", so
861 : : * proceed with seeing if it's a suitable Var.
862 : : */
863 : 0 : clause_expr = clause;
864 : : }
865 : :
866 : : /*
867 : : * We may ignore any RelabelType node above the operand. (There won't be
868 : : * more than one, since eval_const_expressions has been applied already.)
869 : : */
870 [ + - ]: 605 : if (IsA(clause_expr, RelabelType))
871 : 0 : clause_expr = (Node *) ((RelabelType *) clause_expr)->arg;
872 : :
873 : : /* We only support plain Vars for now */
874 [ + + ]: 605 : if (!IsA(clause_expr, Var))
875 : 48 : return false;
876 : :
877 : : /* OK, we know we have a Var */
878 : 557 : var = (Var *) clause_expr;
879 : :
880 : : /* Ensure Var is from the correct relation */
881 [ - + ]: 557 : if (var->varno != relid)
882 : 0 : return false;
883 : :
884 : : /* We also better ensure the Var is from the current level */
885 [ - + ]: 557 : if (var->varlevelsup != 0)
886 : 0 : return false;
887 : :
888 : : /* Also ignore system attributes (we don't allow stats on those) */
889 [ + - ]: 557 : if (!AttrNumberIsForUserDefinedAttr(var->varattno))
890 : 0 : return false;
891 : :
892 : 557 : *attnum = var->varattno;
893 : 557 : return true;
894 : 660 : }
895 : :
896 : : /*
897 : : * find_strongest_dependency
898 : : * find the strongest dependency on the attributes
899 : : *
900 : : * When applying functional dependencies, we start with the strongest
901 : : * dependencies. That is, we select the dependency that:
902 : : *
903 : : * (a) has all attributes covered by equality clauses
904 : : *
905 : : * (b) has the most attributes
906 : : *
907 : : * (c) has the highest degree of validity
908 : : *
909 : : * This guarantees that we eliminate the most redundant conditions first
910 : : * (see the comment in dependencies_clauselist_selectivity).
911 : : */
912 : : static MVDependency *
913 : 581 : find_strongest_dependency(MVDependencies **dependencies, int ndependencies,
914 : : Bitmapset *attnums)
915 : : {
916 : 581 : int i,
917 : : j;
918 : 581 : MVDependency *strongest = NULL;
919 : :
920 : : /* number of attnums in clauses */
921 : 581 : int nattnums = bms_num_members(attnums);
922 : :
923 : : /*
924 : : * Iterate over the MVDependency items and find the strongest one from the
925 : : * fully-matched dependencies. We do the cheap checks first, before
926 : : * matching it against the attnums.
927 : : */
928 [ + + ]: 1168 : for (i = 0; i < ndependencies; i++)
929 : : {
930 [ + + ]: 3380 : for (j = 0; j < dependencies[i]->ndeps; j++)
931 : : {
932 : 2793 : MVDependency *dependency = dependencies[i]->deps[j];
933 : :
934 : : /*
935 : : * Skip dependencies referencing more attributes than available
936 : : * clauses, as those can't be fully matched.
937 : : */
938 [ + + ]: 2793 : if (dependency->nattributes > nattnums)
939 : 1767 : continue;
940 : :
941 [ + + ]: 1026 : if (strongest)
942 : : {
943 : : /* skip dependencies on fewer attributes than the strongest. */
944 [ - + ]: 656 : if (dependency->nattributes < strongest->nattributes)
945 : 0 : continue;
946 : :
947 : : /* also skip weaker dependencies when attribute count matches */
948 [ + + + - ]: 656 : if (strongest->nattributes == dependency->nattributes &&
949 : 609 : strongest->degree > dependency->degree)
950 : 0 : continue;
951 : 656 : }
952 : :
953 : : /*
954 : : * this dependency is stronger, but we must still check that it's
955 : : * fully matched to these attnums. We perform this check last as
956 : : * it's slightly more expensive than the previous checks.
957 : : */
958 [ + + ]: 1026 : if (dependency_is_fully_matched(dependency, attnums))
959 : 514 : strongest = dependency; /* save new best match */
960 [ - + + ]: 2793 : }
961 : 587 : }
962 : :
963 : 1162 : return strongest;
964 : 581 : }
965 : :
966 : : /*
967 : : * clauselist_apply_dependencies
968 : : * Apply the specified functional dependencies to a list of clauses and
969 : : * return the estimated selectivity of the clauses that are compatible
970 : : * with any of the given dependencies.
971 : : *
972 : : * This will estimate all not-already-estimated clauses that are compatible
973 : : * with functional dependencies, and which have an attribute mentioned by any
974 : : * of the given dependencies (either as an implying or implied attribute).
975 : : *
976 : : * Given (lists of) clauses on attributes (a,b) and a functional dependency
977 : : * (a=>b), the per-column selectivities P(a) and P(b) are notionally combined
978 : : * using the formula
979 : : *
980 : : * P(a,b) = f * P(a) + (1-f) * P(a) * P(b)
981 : : *
982 : : * where 'f' is the degree of dependency. This reflects the fact that we
983 : : * expect a fraction f of all rows to be consistent with the dependency
984 : : * (a=>b), and so have a selectivity of P(a), while the remaining rows are
985 : : * treated as independent.
986 : : *
987 : : * In practice, we use a slightly modified version of this formula, which uses
988 : : * a selectivity of Min(P(a), P(b)) for the dependent rows, since the result
989 : : * should obviously not exceed either column's individual selectivity. I.e.,
990 : : * we actually combine selectivities using the formula
991 : : *
992 : : * P(a,b) = f * Min(P(a), P(b)) + (1-f) * P(a) * P(b)
993 : : *
994 : : * This can make quite a difference if the specific values matching the
995 : : * clauses are not consistent with the functional dependency.
996 : : */
997 : : static Selectivity
998 : 266 : clauselist_apply_dependencies(PlannerInfo *root, List *clauses,
999 : : int varRelid, JoinType jointype,
1000 : : SpecialJoinInfo *sjinfo,
1001 : : MVDependency **dependencies, int ndependencies,
1002 : : AttrNumber *list_attnums,
1003 : : Bitmapset **estimatedclauses)
1004 : : {
1005 : 266 : Bitmapset *attnums;
1006 : 266 : int i;
1007 : 266 : int j;
1008 : 266 : int nattrs;
1009 : 266 : Selectivity *attr_sel;
1010 : 266 : int attidx;
1011 : 266 : int listidx;
1012 : 266 : ListCell *l;
1013 : 266 : Selectivity s1;
1014 : :
1015 : : /*
1016 : : * Extract the attnums of all implying and implied attributes from all the
1017 : : * given dependencies. Each of these attributes is expected to have at
1018 : : * least 1 not-already-estimated compatible clause that we will estimate
1019 : : * here.
1020 : : */
1021 : 266 : attnums = NULL;
1022 [ + + ]: 581 : for (i = 0; i < ndependencies; i++)
1023 : : {
1024 [ + + ]: 992 : for (j = 0; j < dependencies[i]->nattributes; j++)
1025 : : {
1026 : 677 : AttrNumber attnum = dependencies[i]->attributes[j];
1027 : :
1028 : 677 : attnums = bms_add_member(attnums, attnum);
1029 : 677 : }
1030 : 315 : }
1031 : :
1032 : : /*
1033 : : * Compute per-column selectivity estimates for each of these attributes,
1034 : : * and mark all the corresponding clauses as estimated.
1035 : : */
1036 : 266 : nattrs = bms_num_members(attnums);
1037 : 266 : attr_sel = palloc_array(Selectivity, nattrs);
1038 : :
1039 : 266 : attidx = 0;
1040 : 266 : i = -1;
1041 [ + + ]: 849 : while ((i = bms_next_member(attnums, i)) >= 0)
1042 : : {
1043 : 583 : List *attr_clauses = NIL;
1044 : 583 : Selectivity simple_sel;
1045 : :
1046 : 583 : listidx = -1;
1047 [ + - + + : 1906 : foreach(l, clauses)
+ + ]
1048 : : {
1049 : 1323 : Node *clause = (Node *) lfirst(l);
1050 : :
1051 : 1323 : listidx++;
1052 [ + + ]: 1323 : if (list_attnums[listidx] == i)
1053 : : {
1054 : 583 : attr_clauses = lappend(attr_clauses, clause);
1055 : 583 : *estimatedclauses = bms_add_member(*estimatedclauses, listidx);
1056 : 583 : }
1057 : 1323 : }
1058 : :
1059 : 1166 : simple_sel = clauselist_selectivity_ext(root, attr_clauses, varRelid,
1060 : 583 : jointype, sjinfo, false);
1061 : 583 : attr_sel[attidx++] = simple_sel;
1062 : 583 : }
1063 : :
1064 : : /*
1065 : : * Now combine these selectivities using the dependency information. For
1066 : : * chains of dependencies such as a -> b -> c, the b -> c dependency will
1067 : : * come before the a -> b dependency in the array, so we traverse the
1068 : : * array backwards to ensure such chains are computed in the right order.
1069 : : *
1070 : : * As explained above, pairs of selectivities are combined using the
1071 : : * formula
1072 : : *
1073 : : * P(a,b) = f * Min(P(a), P(b)) + (1-f) * P(a) * P(b)
1074 : : *
1075 : : * to ensure that the combined selectivity is never greater than either
1076 : : * individual selectivity.
1077 : : *
1078 : : * Where multiple dependencies apply (e.g., a -> b -> c), we use
1079 : : * conditional probabilities to compute the overall result as follows:
1080 : : *
1081 : : * P(a,b,c) = P(c|a,b) * P(a,b) = P(c|a,b) * P(b|a) * P(a)
1082 : : *
1083 : : * so we replace the selectivities of all implied attributes with
1084 : : * conditional probabilities, that are conditional on all their implying
1085 : : * attributes. The selectivities of all other non-implied attributes are
1086 : : * left as they are.
1087 : : */
1088 [ + + ]: 581 : for (i = ndependencies - 1; i >= 0; i--)
1089 : : {
1090 : 315 : MVDependency *dependency = dependencies[i];
1091 : 315 : AttrNumber attnum;
1092 : 315 : Selectivity s2;
1093 : 315 : double f;
1094 : :
1095 : : /* Selectivity of all the implying attributes */
1096 : 315 : s1 = 1.0;
1097 [ + + ]: 677 : for (j = 0; j < dependency->nattributes - 1; j++)
1098 : : {
1099 : 362 : attnum = dependency->attributes[j];
1100 : 362 : attidx = bms_member_index(attnums, attnum);
1101 : 362 : s1 *= attr_sel[attidx];
1102 : 362 : }
1103 : :
1104 : : /* Original selectivity of the implied attribute */
1105 : 315 : attnum = dependency->attributes[j];
1106 : 315 : attidx = bms_member_index(attnums, attnum);
1107 : 315 : s2 = attr_sel[attidx];
1108 : :
1109 : : /*
1110 : : * Replace s2 with the conditional probability s2 given s1, computed
1111 : : * using the formula P(b|a) = P(a,b) / P(a), which simplifies to
1112 : : *
1113 : : * P(b|a) = f * Min(P(a), P(b)) / P(a) + (1-f) * P(b)
1114 : : *
1115 : : * where P(a) = s1, the selectivity of the implying attributes, and
1116 : : * P(b) = s2, the selectivity of the implied attribute.
1117 : : */
1118 : 315 : f = dependency->degree;
1119 : :
1120 [ + + ]: 315 : if (s1 <= s2)
1121 : 297 : attr_sel[attidx] = f + (1 - f) * s2;
1122 : : else
1123 : 18 : attr_sel[attidx] = f * s2 / s1 + (1 - f) * s2;
1124 : 315 : }
1125 : :
1126 : : /*
1127 : : * The overall selectivity of all the clauses on all these attributes is
1128 : : * then the product of all the original (non-implied) probabilities and
1129 : : * the new conditional (implied) probabilities.
1130 : : */
1131 : 266 : s1 = 1.0;
1132 [ + + ]: 849 : for (i = 0; i < nattrs; i++)
1133 : 583 : s1 *= attr_sel[i];
1134 : :
1135 [ - + + - ]: 532 : CLAMP_PROBABILITY(s1);
1136 : :
1137 : 266 : pfree(attr_sel);
1138 : 266 : bms_free(attnums);
1139 : :
1140 : 532 : return s1;
1141 : 266 : }
1142 : :
1143 : : /*
1144 : : * dependency_is_compatible_expression
1145 : : * Determines if the expression is compatible with functional dependencies
1146 : : *
1147 : : * Similar to dependency_is_compatible_clause, but doesn't enforce that the
1148 : : * expression is a simple Var. On success, return the matching statistics
1149 : : * expression into *expr.
1150 : : */
1151 : : static bool
1152 : 107 : dependency_is_compatible_expression(Node *clause, Index relid, List *statlist, Node **expr)
1153 : : {
1154 : 107 : ListCell *lc,
1155 : : *lc2;
1156 : 107 : Node *clause_expr;
1157 : :
1158 [ + + ]: 107 : if (IsA(clause, RestrictInfo))
1159 : : {
1160 : 92 : RestrictInfo *rinfo = (RestrictInfo *) clause;
1161 : :
1162 : : /* Pseudoconstants are not interesting (they couldn't contain a Var) */
1163 [ + + ]: 92 : if (rinfo->pseudoconstant)
1164 : 1 : return false;
1165 : :
1166 : : /* Clauses referencing multiple, or no, varnos are incompatible */
1167 [ - + ]: 91 : if (bms_membership(rinfo->clause_relids) != BMS_SINGLETON)
1168 : 0 : return false;
1169 : :
1170 : 91 : clause = (Node *) rinfo->clause;
1171 [ + + ]: 92 : }
1172 : :
1173 [ + + ]: 106 : if (is_opclause(clause))
1174 : : {
1175 : : /* If it's an opclause, check for Var = Const or Const = Var. */
1176 : 34 : OpExpr *expr = (OpExpr *) clause;
1177 : :
1178 : : /* Only expressions with two arguments are candidates. */
1179 [ - + ]: 34 : if (list_length(expr->args) != 2)
1180 : 0 : return false;
1181 : :
1182 : : /* Make sure non-selected argument is a pseudoconstant. */
1183 [ + - ]: 34 : if (is_pseudo_constant_clause(lsecond(expr->args)))
1184 : 34 : clause_expr = linitial(expr->args);
1185 [ # # ]: 0 : else if (is_pseudo_constant_clause(linitial(expr->args)))
1186 : 0 : clause_expr = lsecond(expr->args);
1187 : : else
1188 : 0 : return false;
1189 : :
1190 : : /*
1191 : : * If it's not an "=" operator, just ignore the clause, as it's not
1192 : : * compatible with functional dependencies.
1193 : : *
1194 : : * This uses the function for estimating selectivity, not the operator
1195 : : * directly (a bit awkward, but well ...).
1196 : : *
1197 : : * XXX this is pretty dubious; probably it'd be better to check btree
1198 : : * or hash opclass membership, so as not to be fooled by custom
1199 : : * selectivity functions, and to be more consistent with decisions
1200 : : * elsewhere in the planner.
1201 : : */
1202 [ + + ]: 34 : if (get_oprrest(expr->opno) != F_EQSEL)
1203 : 6 : return false;
1204 : :
1205 : : /* OK to proceed with checking "var" */
1206 [ + + ]: 34 : }
1207 [ + + ]: 72 : else if (IsA(clause, ScalarArrayOpExpr))
1208 : : {
1209 : : /* If it's a scalar array operator, check for Var IN Const. */
1210 : 65 : ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) clause;
1211 : :
1212 : : /*
1213 : : * Reject ALL() variant, we only care about ANY/IN.
1214 : : *
1215 : : * FIXME Maybe we should check if all the values are the same, and
1216 : : * allow ALL in that case? Doesn't seem very practical, though.
1217 : : */
1218 [ + + ]: 65 : if (!expr->useOr)
1219 : 6 : return false;
1220 : :
1221 : : /* Only expressions with two arguments are candidates. */
1222 [ - + ]: 59 : if (list_length(expr->args) != 2)
1223 : 0 : return false;
1224 : :
1225 : : /*
1226 : : * We know it's always (Var IN Const), so we assume the var is the
1227 : : * first argument, and pseudoconstant is the second one.
1228 : : */
1229 [ + - ]: 59 : if (!is_pseudo_constant_clause(lsecond(expr->args)))
1230 : 0 : return false;
1231 : :
1232 : 59 : clause_expr = linitial(expr->args);
1233 : :
1234 : : /*
1235 : : * If it's not an "=" operator, just ignore the clause, as it's not
1236 : : * compatible with functional dependencies. The operator is identified
1237 : : * simply by looking at which function it uses to estimate
1238 : : * selectivity. That's a bit strange, but it's what other similar
1239 : : * places do.
1240 : : */
1241 [ + + ]: 59 : if (get_oprrest(expr->opno) != F_EQSEL)
1242 : 30 : return false;
1243 : :
1244 : : /* OK to proceed with checking "var" */
1245 [ + + ]: 65 : }
1246 [ + - ]: 7 : else if (is_orclause(clause))
1247 : : {
1248 : 7 : BoolExpr *bool_expr = (BoolExpr *) clause;
1249 : :
1250 : : /* start with no expression (we'll use the first match) */
1251 : 7 : *expr = NULL;
1252 : :
1253 [ + - + + : 22 : foreach(lc, bool_expr->args)
+ + + + ]
1254 : : {
1255 : 15 : Node *or_expr = NULL;
1256 : :
1257 : : /*
1258 : : * Had we found incompatible expression in the arguments, treat
1259 : : * the whole expression as incompatible.
1260 : : */
1261 [ + + + + ]: 30 : if (!dependency_is_compatible_expression((Node *) lfirst(lc), relid,
1262 : 15 : statlist, &or_expr))
1263 : 1 : return false;
1264 : :
1265 [ + + ]: 14 : if (*expr == NULL)
1266 : 6 : *expr = or_expr;
1267 : :
1268 : : /* ensure all the expressions are the same */
1269 [ + + ]: 14 : if (!equal(or_expr, *expr))
1270 : 1 : return false;
1271 [ + + ]: 15 : }
1272 : :
1273 : : /* the expression is already checked by the recursive call */
1274 : 5 : return true;
1275 : 7 : }
1276 [ # # ]: 0 : else if (is_notclause(clause))
1277 : : {
1278 : : /*
1279 : : * "NOT x" can be interpreted as "x = false", so get the argument and
1280 : : * proceed with seeing if it's a suitable Var.
1281 : : */
1282 : 0 : clause_expr = (Node *) get_notclausearg(clause);
1283 : 0 : }
1284 : : else
1285 : : {
1286 : : /*
1287 : : * A boolean expression "x" can be interpreted as "x = true", so
1288 : : * proceed with seeing if it's a suitable Var.
1289 : : */
1290 : 0 : clause_expr = clause;
1291 : : }
1292 : :
1293 : : /*
1294 : : * We may ignore any RelabelType node above the operand. (There won't be
1295 : : * more than one, since eval_const_expressions has been applied already.)
1296 : : */
1297 [ + - ]: 57 : if (IsA(clause_expr, RelabelType))
1298 : 0 : clause_expr = (Node *) ((RelabelType *) clause_expr)->arg;
1299 : :
1300 : : /*
1301 : : * Search for a matching statistics expression.
1302 : : */
1303 [ + - + + : 114 : foreach(lc, statlist)
+ + + + ]
1304 : : {
1305 : 57 : StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
1306 : :
1307 : : /* ignore stats without dependencies */
1308 [ - + ]: 57 : if (info->kind != STATS_EXT_DEPENDENCIES)
1309 : 0 : continue;
1310 : :
1311 [ + + - + : 149 : foreach(lc2, info->exprs)
+ + + + ]
1312 : : {
1313 : 92 : Node *stat_expr = (Node *) lfirst(lc2);
1314 : :
1315 [ + + ]: 92 : if (equal(clause_expr, stat_expr))
1316 : : {
1317 : 56 : *expr = stat_expr;
1318 : 56 : return true;
1319 : : }
1320 [ + + ]: 92 : }
1321 [ + - + ]: 57 : }
1322 : :
1323 : 1 : return false;
1324 : 107 : }
1325 : :
1326 : : /*
1327 : : * dependencies_clauselist_selectivity
1328 : : * Return the estimated selectivity of (a subset of) the given clauses
1329 : : * using functional dependency statistics, or 1.0 if no useful functional
1330 : : * dependency statistic exists.
1331 : : *
1332 : : * 'estimatedclauses' is an input/output argument that gets a bit set
1333 : : * corresponding to the (zero-based) list index of each clause that is included
1334 : : * in the estimated selectivity.
1335 : : *
1336 : : * Given equality clauses on attributes (a,b) we find the strongest dependency
1337 : : * between them, i.e. either (a=>b) or (b=>a). Assuming (a=>b) is the selected
1338 : : * dependency, we then combine the per-clause selectivities using the formula
1339 : : *
1340 : : * P(a,b) = f * P(a) + (1-f) * P(a) * P(b)
1341 : : *
1342 : : * where 'f' is the degree of the dependency. (Actually we use a slightly
1343 : : * modified version of this formula -- see clauselist_apply_dependencies()).
1344 : : *
1345 : : * With clauses on more than two attributes, the dependencies are applied
1346 : : * recursively, starting with the widest/strongest dependencies. For example
1347 : : * P(a,b,c) is first split like this:
1348 : : *
1349 : : * P(a,b,c) = f * P(a,b) + (1-f) * P(a,b) * P(c)
1350 : : *
1351 : : * assuming (a,b=>c) is the strongest dependency.
1352 : : */
1353 : : Selectivity
1354 : 406 : dependencies_clauselist_selectivity(PlannerInfo *root,
1355 : : List *clauses,
1356 : : int varRelid,
1357 : : JoinType jointype,
1358 : : SpecialJoinInfo *sjinfo,
1359 : : RelOptInfo *rel,
1360 : : Bitmapset **estimatedclauses)
1361 : : {
1362 : 406 : Selectivity s1 = 1.0;
1363 : 406 : ListCell *l;
1364 : 406 : Bitmapset *clauses_attnums = NULL;
1365 : 406 : AttrNumber *list_attnums;
1366 : 406 : int listidx;
1367 : 406 : MVDependencies **func_dependencies;
1368 : 406 : int nfunc_dependencies;
1369 : 406 : int total_ndeps;
1370 : 406 : MVDependency **dependencies;
1371 : 406 : int ndependencies;
1372 : 406 : int i;
1373 : 406 : AttrNumber attnum_offset;
1374 [ - + ]: 406 : RangeTblEntry *rte = planner_rt_fetch(rel->relid, root);
1375 : :
1376 : : /* unique expressions */
1377 : 406 : Node **unique_exprs;
1378 : 406 : int unique_exprs_cnt;
1379 : :
1380 : : /* check if there's any stats that might be useful for us. */
1381 [ + + ]: 406 : if (!has_stats_of_kind(rel->statlist, STATS_EXT_DEPENDENCIES))
1382 : 108 : return 1.0;
1383 : :
1384 : 298 : list_attnums = palloc_array(AttrNumber, list_length(clauses));
1385 : :
1386 : : /*
1387 : : * We allocate space as if every clause was a unique expression, although
1388 : : * that's probably overkill. Some will be simple column references that
1389 : : * we'll translate to attnums, and there might be duplicates. But it's
1390 : : * easier and cheaper to just do one allocation than repalloc later.
1391 : : */
1392 : 298 : unique_exprs = palloc_array(Node *, list_length(clauses));
1393 : 298 : unique_exprs_cnt = 0;
1394 : :
1395 : : /*
1396 : : * Pre-process the clauses list to extract the attnums seen in each item.
1397 : : * We need to determine if there's any clauses which will be useful for
1398 : : * dependency selectivity estimations. Along the way we'll record all of
1399 : : * the attnums for each clause in a list which we'll reference later so we
1400 : : * don't need to repeat the same work again. We'll also keep track of all
1401 : : * attnums seen.
1402 : : *
1403 : : * We also skip clauses that we already estimated using different types of
1404 : : * statistics (we treat them as incompatible).
1405 : : *
1406 : : * To handle expressions, we assign them negative attnums, as if it was a
1407 : : * system attribute (this is fine, as we only allow extended stats on user
1408 : : * attributes). And then we offset everything by the number of
1409 : : * expressions, so that we can store the values in a bitmapset.
1410 : : */
1411 : 298 : listidx = 0;
1412 [ + - + + : 945 : foreach(l, clauses)
+ + ]
1413 : : {
1414 : 647 : Node *clause = (Node *) lfirst(l);
1415 : 647 : AttrNumber attnum;
1416 : 647 : Node *expr = NULL;
1417 : :
1418 : : /* ignore clause by default */
1419 : 647 : list_attnums[listidx] = InvalidAttrNumber;
1420 : :
1421 [ + + ]: 647 : if (!bms_is_member(listidx, *estimatedclauses))
1422 : : {
1423 : : /*
1424 : : * If it's a simple column reference, just extract the attnum. If
1425 : : * it's an expression, assign a negative attnum as if it was a
1426 : : * system attribute.
1427 : : */
1428 [ + + ]: 640 : if (dependency_is_compatible_clause(clause, rel->relid, &attnum))
1429 : : {
1430 : 548 : list_attnums[listidx] = attnum;
1431 : 548 : }
1432 [ + + + + ]: 184 : else if (dependency_is_compatible_expression(clause, rel->relid,
1433 : 92 : rel->statlist,
1434 : : &expr))
1435 : : {
1436 : : /* special attnum assigned to this expression */
1437 : 47 : attnum = InvalidAttrNumber;
1438 : :
1439 [ - + ]: 47 : Assert(expr != NULL);
1440 : :
1441 : : /* If the expression is duplicate, use the same attnum. */
1442 [ + + ]: 79 : for (i = 0; i < unique_exprs_cnt; i++)
1443 : : {
1444 [ - + ]: 32 : if (equal(unique_exprs[i], expr))
1445 : : {
1446 : : /* negative attribute number to expression */
1447 : 0 : attnum = -(i + 1);
1448 : 0 : break;
1449 : : }
1450 : 32 : }
1451 : :
1452 : : /* not found in the list, so add it */
1453 [ + - ]: 47 : if (attnum == InvalidAttrNumber)
1454 : : {
1455 : 47 : unique_exprs[unique_exprs_cnt++] = expr;
1456 : :
1457 : : /* after incrementing the value, to get -1, -2, ... */
1458 : 47 : attnum = (-unique_exprs_cnt);
1459 : 47 : }
1460 : :
1461 : : /* remember which attnum was assigned to this clause */
1462 : 47 : list_attnums[listidx] = attnum;
1463 : 47 : }
1464 : 640 : }
1465 : :
1466 : 647 : listidx++;
1467 : 647 : }
1468 : :
1469 [ + - ]: 298 : Assert(listidx == list_length(clauses));
1470 : :
1471 : : /*
1472 : : * How much we need to offset the attnums? If there are no expressions,
1473 : : * then no offset is needed. Otherwise we need to offset enough for the
1474 : : * lowest value (-unique_exprs_cnt) to become 1.
1475 : : */
1476 [ + + ]: 298 : if (unique_exprs_cnt > 0)
1477 : 22 : attnum_offset = (unique_exprs_cnt + 1);
1478 : : else
1479 : 276 : attnum_offset = 0;
1480 : :
1481 : : /*
1482 : : * Now that we know how many expressions there are, we can offset the
1483 : : * values just enough to build the bitmapset.
1484 : : */
1485 [ + + ]: 945 : for (i = 0; i < list_length(clauses); i++)
1486 : : {
1487 : 647 : AttrNumber attnum;
1488 : :
1489 : : /* ignore incompatible or already estimated clauses */
1490 [ + + ]: 647 : if (list_attnums[i] == InvalidAttrNumber)
1491 : 52 : continue;
1492 : :
1493 : : /* make sure the attnum is in the expected range */
1494 [ - + ]: 595 : Assert(list_attnums[i] >= (-unique_exprs_cnt));
1495 [ - + ]: 595 : Assert(list_attnums[i] <= MaxHeapAttributeNumber);
1496 : :
1497 : : /* make sure the attnum is positive (valid AttrNumber) */
1498 : 595 : attnum = list_attnums[i] + attnum_offset;
1499 : :
1500 : : /*
1501 : : * Either it's a regular attribute, or it's an expression, in which
1502 : : * case we must not have seen it before (expressions are unique).
1503 : : *
1504 : : * XXX Check whether it's a regular attribute has to be done using the
1505 : : * original attnum, while the second check has to use the value with
1506 : : * an offset.
1507 : : */
1508 [ + + - + ]: 595 : Assert(AttrNumberIsForUserDefinedAttr(list_attnums[i]) ||
1509 : : !bms_is_member(attnum, clauses_attnums));
1510 : :
1511 : : /*
1512 : : * Remember the offset attnum, both for attributes and expressions.
1513 : : * We'll pass list_attnums to clauselist_apply_dependencies, which
1514 : : * uses it to identify clauses in a bitmap. We could also pass the
1515 : : * offset, but this is more convenient.
1516 : : */
1517 : 595 : list_attnums[i] = attnum;
1518 : :
1519 : 595 : clauses_attnums = bms_add_member(clauses_attnums, attnum);
1520 [ + + ]: 647 : }
1521 : :
1522 : : /*
1523 : : * If there's not at least two distinct attnums and expressions, then
1524 : : * reject the whole list of clauses. We must return 1.0 so the calling
1525 : : * function's selectivity is unaffected.
1526 : : */
1527 [ + + ]: 298 : if (bms_membership(clauses_attnums) != BMS_MULTIPLE)
1528 : : {
1529 : 32 : bms_free(clauses_attnums);
1530 : 32 : pfree(list_attnums);
1531 : 32 : return 1.0;
1532 : : }
1533 : :
1534 : : /*
1535 : : * Load all functional dependencies matching at least two parameters. We
1536 : : * can simply consider all dependencies at once, without having to search
1537 : : * for the best statistics object.
1538 : : *
1539 : : * To not waste cycles and memory, we deserialize dependencies only for
1540 : : * statistics that match at least two attributes. The array is allocated
1541 : : * with the assumption that all objects match - we could grow the array to
1542 : : * make it just the right size, but it's likely wasteful anyway thanks to
1543 : : * moving the freed chunks to freelists etc.
1544 : : */
1545 : 266 : func_dependencies = palloc_array(MVDependencies *, list_length(rel->statlist));
1546 : 266 : nfunc_dependencies = 0;
1547 : 266 : total_ndeps = 0;
1548 : :
1549 [ + - + + : 555 : foreach(l, rel->statlist)
+ + ]
1550 : : {
1551 : 289 : StatisticExtInfo *stat = (StatisticExtInfo *) lfirst(l);
1552 : 289 : int nmatched;
1553 : 289 : int nexprs;
1554 : 289 : int k;
1555 : 289 : MVDependencies *deps;
1556 : :
1557 : : /* skip statistics that are not of the correct type */
1558 [ + + ]: 289 : if (stat->kind != STATS_EXT_DEPENDENCIES)
1559 : 18 : continue;
1560 : :
1561 : : /* skip statistics with mismatching stxdinherit value */
1562 [ - + ]: 271 : if (stat->inherit != rte->inh)
1563 : 0 : continue;
1564 : :
1565 : : /*
1566 : : * Count matching attributes - we have to undo the attnum offsets. The
1567 : : * input attribute numbers are not offset (expressions are not
1568 : : * included in stat->keys, so it's not necessary). But we need to
1569 : : * offset it before checking against clauses_attnums.
1570 : : */
1571 : 271 : nmatched = 0;
1572 : 271 : k = -1;
1573 [ + + ]: 1020 : while ((k = bms_next_member(stat->keys, k)) >= 0)
1574 : : {
1575 : 749 : AttrNumber attnum = (AttrNumber) k;
1576 : :
1577 : : /* skip expressions */
1578 [ - + ]: 749 : if (!AttrNumberIsForUserDefinedAttr(attnum))
1579 : 0 : continue;
1580 : :
1581 : : /* apply the same offset as above */
1582 : 749 : attnum += attnum_offset;
1583 : :
1584 [ + + ]: 749 : if (bms_is_member(attnum, clauses_attnums))
1585 : 540 : nmatched++;
1586 [ - + ]: 749 : }
1587 : :
1588 : : /* count matching expressions */
1589 : 271 : nexprs = 0;
1590 [ + + ]: 314 : for (i = 0; i < unique_exprs_cnt; i++)
1591 : : {
1592 : 43 : ListCell *lc;
1593 : :
1594 [ + - + + : 172 : foreach(lc, stat->exprs)
+ + ]
1595 : : {
1596 : 129 : Node *stat_expr = (Node *) lfirst(lc);
1597 : :
1598 : : /* try to match it */
1599 [ + + ]: 129 : if (equal(stat_expr, unique_exprs[i]))
1600 : 43 : nexprs++;
1601 : 129 : }
1602 : 43 : }
1603 : :
1604 : : /*
1605 : : * Skip objects matching fewer than two attributes/expressions from
1606 : : * clauses.
1607 : : */
1608 [ + + ]: 271 : if (nmatched + nexprs < 2)
1609 : 3 : continue;
1610 : :
1611 : 268 : deps = statext_dependencies_load(stat->statOid, rte->inh);
1612 : :
1613 : : /*
1614 : : * The expressions may be represented by different attnums in the
1615 : : * stats, we need to remap them to be consistent with the clauses.
1616 : : * That will make the later steps (e.g. picking the strongest item and
1617 : : * so on) much simpler and cheaper, because it won't need to care
1618 : : * about the offset at all.
1619 : : *
1620 : : * When we're at it, we can ignore dependencies that are not fully
1621 : : * matched by clauses (i.e. referencing attributes or expressions that
1622 : : * are not in the clauses).
1623 : : *
1624 : : * We have to do this for all statistics, as long as there are any
1625 : : * expressions - we need to shift the attnums in all dependencies.
1626 : : *
1627 : : * XXX Maybe we should do this always, because it also eliminates some
1628 : : * of the dependencies early. It might be cheaper than having to walk
1629 : : * the longer list in find_strongest_dependency later, especially as
1630 : : * we need to do that repeatedly?
1631 : : *
1632 : : * XXX We have to do this even when there are no expressions in
1633 : : * clauses, otherwise find_strongest_dependency may fail for stats
1634 : : * with expressions (due to lookup of negative value in bitmap). So we
1635 : : * need to at least filter out those dependencies. Maybe we could do
1636 : : * it in a cheaper way (if there are no expr clauses, we can just
1637 : : * discard all negative attnums without any lookups).
1638 : : */
1639 [ + + - + ]: 268 : if (unique_exprs_cnt > 0 || stat->exprs != NIL)
1640 : : {
1641 : 18 : int ndeps = 0;
1642 : :
1643 [ + + ]: 108 : for (i = 0; i < deps->ndeps; i++)
1644 : : {
1645 : 90 : bool skip = false;
1646 : 90 : MVDependency *dep = deps->deps[i];
1647 : 90 : int j;
1648 : :
1649 [ + + ]: 251 : for (j = 0; j < dep->nattributes; j++)
1650 : : {
1651 : 205 : int idx;
1652 : 205 : Node *expr;
1653 : 205 : AttrNumber unique_attnum = InvalidAttrNumber;
1654 : 205 : AttrNumber attnum;
1655 : :
1656 : : /* undo the per-statistics offset */
1657 : 205 : attnum = dep->attributes[j];
1658 : :
1659 : : /*
1660 : : * For regular attributes we can simply check if it
1661 : : * matches any clause. If there's no matching clause, we
1662 : : * can just ignore it. We need to offset the attnum
1663 : : * though.
1664 : : */
1665 [ - + ]: 205 : if (AttrNumberIsForUserDefinedAttr(attnum))
1666 : : {
1667 : 0 : dep->attributes[j] = attnum + attnum_offset;
1668 : :
1669 [ # # ]: 0 : if (!bms_is_member(dep->attributes[j], clauses_attnums))
1670 : : {
1671 : 0 : skip = true;
1672 : 0 : break;
1673 : : }
1674 : :
1675 : 0 : continue;
1676 : : }
1677 : :
1678 : : /*
1679 : : * the attnum should be a valid system attnum (-1, -2,
1680 : : * ...)
1681 : : */
1682 [ + - ]: 205 : Assert(AttributeNumberIsValid(attnum));
1683 : :
1684 : : /*
1685 : : * For expressions, we need to do two translations. First
1686 : : * we have to translate the negative attnum to index in
1687 : : * the list of expressions (in the statistics object).
1688 : : * Then we need to see if there's a matching clause. The
1689 : : * index of the unique expression determines the attnum
1690 : : * (and we offset it).
1691 : : */
1692 : 205 : idx = -(1 + attnum);
1693 : :
1694 : : /* Is the expression index is valid? */
1695 [ + - ]: 205 : Assert((idx >= 0) && (idx < list_length(stat->exprs)));
1696 : :
1697 : 205 : expr = (Node *) list_nth(stat->exprs, idx);
1698 : :
1699 : : /* try to find the expression in the unique list */
1700 [ + + ]: 571 : for (int m = 0; m < unique_exprs_cnt; m++)
1701 : : {
1702 : : /*
1703 : : * found a matching unique expression, use the attnum
1704 : : * (derived from index of the unique expression)
1705 : : */
1706 [ + + ]: 366 : if (equal(unique_exprs[m], expr))
1707 : : {
1708 : 161 : unique_attnum = -(m + 1) + attnum_offset;
1709 : 161 : break;
1710 : : }
1711 : 205 : }
1712 : :
1713 : : /*
1714 : : * Found no matching expression, so we can simply skip
1715 : : * this dependency, because there's no chance it will be
1716 : : * fully covered.
1717 : : */
1718 [ + + ]: 205 : if (unique_attnum == InvalidAttrNumber)
1719 : : {
1720 : 44 : skip = true;
1721 : 44 : break;
1722 : : }
1723 : :
1724 : : /* otherwise remap it to the new attnum */
1725 : 161 : dep->attributes[j] = unique_attnum;
1726 [ - + + ]: 205 : }
1727 : :
1728 : : /* if found a matching dependency, keep it */
1729 [ + + ]: 90 : if (!skip)
1730 : : {
1731 : : /* maybe we've skipped something earlier, so move it */
1732 [ + - ]: 46 : if (ndeps != i)
1733 : 0 : deps->deps[ndeps] = deps->deps[i];
1734 : :
1735 : 46 : ndeps++;
1736 : 46 : }
1737 : 90 : }
1738 : :
1739 : 18 : deps->ndeps = ndeps;
1740 : 18 : }
1741 : :
1742 : : /*
1743 : : * It's possible we've removed all dependencies, in which case we
1744 : : * don't bother adding it to the list.
1745 : : */
1746 [ - + ]: 268 : if (deps->ndeps > 0)
1747 : : {
1748 : 268 : func_dependencies[nfunc_dependencies] = deps;
1749 : 268 : total_ndeps += deps->ndeps;
1750 : 268 : nfunc_dependencies++;
1751 : 268 : }
1752 [ + + ]: 289 : }
1753 : :
1754 : : /* if no matching stats could be found then we've nothing to do */
1755 [ + - ]: 266 : if (nfunc_dependencies == 0)
1756 : : {
1757 : 0 : pfree(func_dependencies);
1758 : 0 : bms_free(clauses_attnums);
1759 : 0 : pfree(list_attnums);
1760 : 0 : pfree(unique_exprs);
1761 : 0 : return 1.0;
1762 : : }
1763 : :
1764 : : /*
1765 : : * Work out which dependencies we can apply, starting with the
1766 : : * widest/strongest ones, and proceeding to smaller/weaker ones.
1767 : : */
1768 : 266 : dependencies = palloc_array(MVDependency *, total_ndeps);
1769 : 266 : ndependencies = 0;
1770 : :
1771 : 581 : while (true)
1772 : : {
1773 : 581 : MVDependency *dependency;
1774 : 581 : AttrNumber attnum;
1775 : :
1776 : : /* the widest/strongest dependency, fully matched by clauses */
1777 : 1162 : dependency = find_strongest_dependency(func_dependencies,
1778 : 581 : nfunc_dependencies,
1779 : 581 : clauses_attnums);
1780 [ + + ]: 581 : if (!dependency)
1781 : 266 : break;
1782 : :
1783 : 315 : dependencies[ndependencies++] = dependency;
1784 : :
1785 : : /* Ignore dependencies using this implied attribute in later loops */
1786 : 315 : attnum = dependency->attributes[dependency->nattributes - 1];
1787 : 315 : clauses_attnums = bms_del_member(clauses_attnums, attnum);
1788 [ + + ]: 581 : }
1789 : :
1790 : : /*
1791 : : * If we found applicable dependencies, use them to estimate all
1792 : : * compatible clauses on attributes that they refer to.
1793 : : */
1794 [ - + ]: 266 : if (ndependencies != 0)
1795 : 532 : s1 = clauselist_apply_dependencies(root, clauses, varRelid, jointype,
1796 : 266 : sjinfo, dependencies, ndependencies,
1797 : 266 : list_attnums, estimatedclauses);
1798 : :
1799 : : /* free deserialized functional dependencies (and then the array) */
1800 [ + + ]: 534 : for (i = 0; i < nfunc_dependencies; i++)
1801 : 268 : pfree(func_dependencies[i]);
1802 : :
1803 : 266 : pfree(dependencies);
1804 : 266 : pfree(func_dependencies);
1805 : 266 : bms_free(clauses_attnums);
1806 : 266 : pfree(list_attnums);
1807 : 266 : pfree(unique_exprs);
1808 : :
1809 : 266 : return s1;
1810 : 406 : }
|
