Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * extended_stats.c
4 : * POSTGRES extended statistics
5 : *
6 : * Generic code supporting statistics objects created via CREATE STATISTICS.
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/statistics/extended_stats.c
14 : *
15 : *-------------------------------------------------------------------------
16 : */
17 : #include "postgres.h"
18 :
19 : #include "access/detoast.h"
20 : #include "access/genam.h"
21 : #include "access/htup_details.h"
22 : #include "access/table.h"
23 : #include "catalog/indexing.h"
24 : #include "catalog/pg_statistic_ext.h"
25 : #include "catalog/pg_statistic_ext_data.h"
26 : #include "commands/defrem.h"
27 : #include "commands/progress.h"
28 : #include "executor/executor.h"
29 : #include "miscadmin.h"
30 : #include "nodes/nodeFuncs.h"
31 : #include "optimizer/optimizer.h"
32 : #include "parser/parsetree.h"
33 : #include "pgstat.h"
34 : #include "postmaster/autovacuum.h"
35 : #include "statistics/extended_stats_internal.h"
36 : #include "statistics/statistics.h"
37 : #include "utils/acl.h"
38 : #include "utils/array.h"
39 : #include "utils/attoptcache.h"
40 : #include "utils/builtins.h"
41 : #include "utils/datum.h"
42 : #include "utils/fmgroids.h"
43 : #include "utils/lsyscache.h"
44 : #include "utils/memutils.h"
45 : #include "utils/rel.h"
46 : #include "utils/selfuncs.h"
47 : #include "utils/syscache.h"
48 :
49 : /*
50 : * To avoid consuming too much memory during analysis and/or too much space
51 : * in the resulting pg_statistic rows, we ignore varlena datums that are wider
52 : * than WIDTH_THRESHOLD (after detoasting!). This is legitimate for MCV
53 : * and distinct-value calculations since a wide value is unlikely to be
54 : * duplicated at all, much less be a most-common value. For the same reason,
55 : * ignoring wide values will not affect our estimates of histogram bin
56 : * boundaries very much.
57 : */
58 : #define WIDTH_THRESHOLD 1024
59 :
60 : /*
61 : * Used internally to refer to an individual statistics object, i.e.,
62 : * a pg_statistic_ext entry.
63 : */
64 : typedef struct StatExtEntry
65 : {
66 : Oid statOid; /* OID of pg_statistic_ext entry */
67 : char *schema; /* statistics object's schema */
68 : char *name; /* statistics object's name */
69 : Bitmapset *columns; /* attribute numbers covered by the object */
70 : List *types; /* 'char' list of enabled statistics kinds */
71 : int stattarget; /* statistics target (-1 for default) */
72 : List *exprs; /* expressions */
73 : } StatExtEntry;
74 :
75 :
76 : static List *fetch_statentries_for_relation(Relation pg_statext, Oid relid);
77 : static VacAttrStats **lookup_var_attr_stats(Bitmapset *attrs, List *exprs,
78 : int nvacatts, VacAttrStats **vacatts);
79 : static void statext_store(Oid statOid, bool inh,
80 : MVNDistinct *ndistinct, MVDependencies *dependencies,
81 : MCVList *mcv, Datum exprs, VacAttrStats **stats);
82 : static int statext_compute_stattarget(int stattarget,
83 : int nattrs, VacAttrStats **stats);
84 :
85 : /* Information needed to analyze a single simple expression. */
86 : typedef struct AnlExprData
87 : {
88 : Node *expr; /* expression to analyze */
89 : VacAttrStats *vacattrstat; /* statistics attrs to analyze */
90 : } AnlExprData;
91 :
92 : static void compute_expr_stats(Relation onerel, AnlExprData *exprdata,
93 : int nexprs, HeapTuple *rows, int numrows);
94 : static Datum serialize_expr_stats(AnlExprData *exprdata, int nexprs);
95 : static Datum expr_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
96 : static AnlExprData *build_expr_data(List *exprs, int stattarget);
97 :
98 : static StatsBuildData *make_build_data(Relation rel, StatExtEntry *stat,
99 : int numrows, HeapTuple *rows,
100 : VacAttrStats **stats, int stattarget);
101 :
102 :
103 : /*
104 : * Compute requested extended stats, using the rows sampled for the plain
105 : * (single-column) stats.
106 : *
107 : * This fetches a list of stats types from pg_statistic_ext, computes the
108 : * requested stats, and serializes them back into the catalog.
109 : */
110 : void
111 5734 : BuildRelationExtStatistics(Relation onerel, bool inh, double totalrows,
112 : int numrows, HeapTuple *rows,
113 : int natts, VacAttrStats **vacattrstats)
114 : {
115 : Relation pg_stext;
116 : ListCell *lc;
117 : List *statslist;
118 : MemoryContext cxt;
119 : MemoryContext oldcxt;
120 : int64 ext_cnt;
121 :
122 : /* Do nothing if there are no columns to analyze. */
123 5734 : if (!natts)
124 9 : return;
125 :
126 : /* the list of stats has to be allocated outside the memory context */
127 5725 : pg_stext = table_open(StatisticExtRelationId, RowExclusiveLock);
128 5725 : statslist = fetch_statentries_for_relation(pg_stext, RelationGetRelid(onerel));
129 :
130 : /* memory context for building each statistics object */
131 5725 : cxt = AllocSetContextCreate(CurrentMemoryContext,
132 : "BuildRelationExtStatistics",
133 : ALLOCSET_DEFAULT_SIZES);
134 5725 : oldcxt = MemoryContextSwitchTo(cxt);
135 :
136 : /* report this phase */
137 5725 : if (statslist != NIL)
138 : {
139 177 : const int index[] = {
140 : PROGRESS_ANALYZE_PHASE,
141 : PROGRESS_ANALYZE_EXT_STATS_TOTAL
142 : };
143 354 : const int64 val[] = {
144 : PROGRESS_ANALYZE_PHASE_COMPUTE_EXT_STATS,
145 177 : list_length(statslist)
146 : };
147 :
148 177 : pgstat_progress_update_multi_param(2, index, val);
149 : }
150 :
151 5725 : ext_cnt = 0;
152 5995 : foreach(lc, statslist)
153 : {
154 270 : StatExtEntry *stat = (StatExtEntry *) lfirst(lc);
155 270 : MVNDistinct *ndistinct = NULL;
156 270 : MVDependencies *dependencies = NULL;
157 270 : MCVList *mcv = NULL;
158 270 : Datum exprstats = (Datum) 0;
159 : VacAttrStats **stats;
160 : ListCell *lc2;
161 : int stattarget;
162 : StatsBuildData *data;
163 :
164 : /*
165 : * Check if we can build these stats based on the column analyzed. If
166 : * not, report this fact (except in autovacuum) and move on.
167 : */
168 270 : stats = lookup_var_attr_stats(stat->columns, stat->exprs,
169 : natts, vacattrstats);
170 270 : if (!stats)
171 : {
172 8 : if (!AmAutoVacuumWorkerProcess())
173 8 : ereport(WARNING,
174 : (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
175 : errmsg("statistics object \"%s.%s\" could not be computed for relation \"%s.%s\"",
176 : stat->schema, stat->name,
177 : get_namespace_name(onerel->rd_rel->relnamespace),
178 : RelationGetRelationName(onerel)),
179 : errtable(onerel)));
180 8 : continue;
181 : }
182 :
183 : /* compute statistics target for this statistics object */
184 262 : stattarget = statext_compute_stattarget(stat->stattarget,
185 262 : bms_num_members(stat->columns),
186 : stats);
187 :
188 : /*
189 : * Don't rebuild statistics objects with statistics target set to 0
190 : * (we just leave the existing values around, just like we do for
191 : * regular per-column statistics).
192 : */
193 262 : if (stattarget == 0)
194 3 : continue;
195 :
196 : /* evaluate expressions (if the statistics object has any) */
197 259 : data = make_build_data(onerel, stat, numrows, rows, stats, stattarget);
198 :
199 : /* compute statistic of each requested type */
200 739 : foreach(lc2, stat->types)
201 : {
202 480 : char t = (char) lfirst_int(lc2);
203 :
204 480 : if (t == STATS_EXT_NDISTINCT)
205 127 : ndistinct = statext_ndistinct_build(totalrows, data);
206 353 : else if (t == STATS_EXT_DEPENDENCIES)
207 100 : dependencies = statext_dependencies_build(data);
208 253 : else if (t == STATS_EXT_MCV)
209 139 : mcv = statext_mcv_build(data, totalrows, stattarget);
210 114 : else if (t == STATS_EXT_EXPRESSIONS)
211 : {
212 : AnlExprData *exprdata;
213 : int nexprs;
214 :
215 : /* should not happen, thanks to checks when defining stats */
216 114 : if (!stat->exprs)
217 0 : elog(ERROR, "requested expression stats, but there are no expressions");
218 :
219 114 : exprdata = build_expr_data(stat->exprs, stattarget);
220 114 : nexprs = list_length(stat->exprs);
221 :
222 114 : compute_expr_stats(onerel, exprdata, nexprs, rows, numrows);
223 :
224 114 : exprstats = serialize_expr_stats(exprdata, nexprs);
225 : }
226 : }
227 :
228 : /* store the statistics in the catalog */
229 259 : statext_store(stat->statOid, inh,
230 : ndistinct, dependencies, mcv, exprstats, stats);
231 :
232 : /* for reporting progress */
233 259 : pgstat_progress_update_param(PROGRESS_ANALYZE_EXT_STATS_COMPUTED,
234 : ++ext_cnt);
235 :
236 : /* free the data used for building this statistics object */
237 259 : MemoryContextReset(cxt);
238 : }
239 :
240 5725 : MemoryContextSwitchTo(oldcxt);
241 5725 : MemoryContextDelete(cxt);
242 :
243 5725 : list_free(statslist);
244 :
245 5725 : table_close(pg_stext, RowExclusiveLock);
246 : }
247 :
248 : /*
249 : * ComputeExtStatisticsRows
250 : * Compute number of rows required by extended statistics on a table.
251 : *
252 : * Computes number of rows we need to sample to build extended statistics on a
253 : * table. This only looks at statistics we can actually build - for example
254 : * when analyzing only some of the columns, this will skip statistics objects
255 : * that would require additional columns.
256 : *
257 : * See statext_compute_stattarget for details about how we compute the
258 : * statistics target for a statistics object (from the object target,
259 : * attribute targets and default statistics target).
260 : */
261 : int
262 8433 : ComputeExtStatisticsRows(Relation onerel,
263 : int natts, VacAttrStats **vacattrstats)
264 : {
265 : Relation pg_stext;
266 : ListCell *lc;
267 : List *lstats;
268 : MemoryContext cxt;
269 : MemoryContext oldcxt;
270 8433 : int result = 0;
271 :
272 : /* If there are no columns to analyze, just return 0. */
273 8433 : if (!natts)
274 36 : return 0;
275 :
276 8397 : cxt = AllocSetContextCreate(CurrentMemoryContext,
277 : "ComputeExtStatisticsRows",
278 : ALLOCSET_DEFAULT_SIZES);
279 8397 : oldcxt = MemoryContextSwitchTo(cxt);
280 :
281 8397 : pg_stext = table_open(StatisticExtRelationId, RowExclusiveLock);
282 8397 : lstats = fetch_statentries_for_relation(pg_stext, RelationGetRelid(onerel));
283 :
284 8667 : foreach(lc, lstats)
285 : {
286 270 : StatExtEntry *stat = (StatExtEntry *) lfirst(lc);
287 : int stattarget;
288 : VacAttrStats **stats;
289 270 : int nattrs = bms_num_members(stat->columns);
290 :
291 : /*
292 : * Check if we can build this statistics object based on the columns
293 : * analyzed. If not, ignore it (don't report anything, we'll do that
294 : * during the actual build BuildRelationExtStatistics).
295 : */
296 270 : stats = lookup_var_attr_stats(stat->columns, stat->exprs,
297 : natts, vacattrstats);
298 :
299 270 : if (!stats)
300 8 : continue;
301 :
302 : /*
303 : * Compute statistics target, based on what's set for the statistic
304 : * object itself, and for its attributes.
305 : */
306 262 : stattarget = statext_compute_stattarget(stat->stattarget,
307 : nattrs, stats);
308 :
309 : /* Use the largest value for all statistics objects. */
310 262 : if (stattarget > result)
311 166 : result = stattarget;
312 : }
313 :
314 8397 : table_close(pg_stext, RowExclusiveLock);
315 :
316 8397 : MemoryContextSwitchTo(oldcxt);
317 8397 : MemoryContextDelete(cxt);
318 :
319 : /* compute sample size based on the statistics target */
320 8397 : return (300 * result);
321 : }
322 :
323 : /*
324 : * statext_compute_stattarget
325 : * compute statistics target for an extended statistic
326 : *
327 : * When computing target for extended statistics objects, we consider three
328 : * places where the target may be set - the statistics object itself,
329 : * attributes the statistics object is defined on, and then the default
330 : * statistics target.
331 : *
332 : * First we look at what's set for the statistics object itself, using the
333 : * ALTER STATISTICS ... SET STATISTICS command. If we find a valid value
334 : * there (i.e. not -1) we're done. Otherwise we look at targets set for any
335 : * of the attributes the statistic is defined on, and if there are columns
336 : * with defined target, we use the maximum value. We do this mostly for
337 : * backwards compatibility, because this is what we did before having
338 : * statistics target for extended statistics.
339 : *
340 : * And finally, if we still don't have a statistics target, we use the value
341 : * set in default_statistics_target.
342 : */
343 : static int
344 524 : statext_compute_stattarget(int stattarget, int nattrs, VacAttrStats **stats)
345 : {
346 : int i;
347 :
348 : /*
349 : * If there's statistics target set for the statistics object, use it. It
350 : * may be set to 0 which disables building of that statistic.
351 : */
352 524 : if (stattarget >= 0)
353 6 : return stattarget;
354 :
355 : /*
356 : * The target for the statistics object is set to -1, in which case we
357 : * look at the maximum target set for any of the attributes the object is
358 : * defined on.
359 : */
360 1368 : for (i = 0; i < nattrs; i++)
361 : {
362 : /* keep the maximum statistics target */
363 850 : if (stats[i]->attstattarget > stattarget)
364 386 : stattarget = stats[i]->attstattarget;
365 : }
366 :
367 : /*
368 : * If the value is still negative (so neither the statistics object nor
369 : * any of the columns have custom statistics target set), use the global
370 : * default target.
371 : */
372 518 : if (stattarget < 0)
373 132 : stattarget = default_statistics_target;
374 :
375 : /* As this point we should have a valid statistics target. */
376 : Assert((stattarget >= 0) && (stattarget <= MAX_STATISTICS_TARGET));
377 :
378 518 : return stattarget;
379 : }
380 :
381 : /*
382 : * statext_is_kind_built
383 : * Is this stat kind built in the given pg_statistic_ext_data tuple?
384 : */
385 : bool
386 4020 : statext_is_kind_built(HeapTuple htup, char type)
387 : {
388 : AttrNumber attnum;
389 :
390 4020 : switch (type)
391 : {
392 1005 : case STATS_EXT_NDISTINCT:
393 1005 : attnum = Anum_pg_statistic_ext_data_stxdndistinct;
394 1005 : break;
395 :
396 1005 : case STATS_EXT_DEPENDENCIES:
397 1005 : attnum = Anum_pg_statistic_ext_data_stxddependencies;
398 1005 : break;
399 :
400 1005 : case STATS_EXT_MCV:
401 1005 : attnum = Anum_pg_statistic_ext_data_stxdmcv;
402 1005 : break;
403 :
404 1005 : case STATS_EXT_EXPRESSIONS:
405 1005 : attnum = Anum_pg_statistic_ext_data_stxdexpr;
406 1005 : break;
407 :
408 0 : default:
409 0 : elog(ERROR, "unexpected statistics type requested: %d", type);
410 : }
411 :
412 4020 : return !heap_attisnull(htup, attnum, NULL);
413 : }
414 :
415 : /*
416 : * Return a list (of StatExtEntry) of statistics objects for the given relation.
417 : */
418 : static List *
419 14122 : fetch_statentries_for_relation(Relation pg_statext, Oid relid)
420 : {
421 : SysScanDesc scan;
422 : ScanKeyData skey;
423 : HeapTuple htup;
424 14122 : List *result = NIL;
425 :
426 : /*
427 : * Prepare to scan pg_statistic_ext for entries having stxrelid = this
428 : * rel.
429 : */
430 14122 : ScanKeyInit(&skey,
431 : Anum_pg_statistic_ext_stxrelid,
432 : BTEqualStrategyNumber, F_OIDEQ,
433 : ObjectIdGetDatum(relid));
434 :
435 14122 : scan = systable_beginscan(pg_statext, StatisticExtRelidIndexId, true,
436 : NULL, 1, &skey);
437 :
438 14662 : while (HeapTupleIsValid(htup = systable_getnext(scan)))
439 : {
440 : StatExtEntry *entry;
441 : Datum datum;
442 : bool isnull;
443 : int i;
444 : ArrayType *arr;
445 : char *enabled;
446 : Form_pg_statistic_ext staForm;
447 540 : List *exprs = NIL;
448 :
449 540 : entry = palloc0_object(StatExtEntry);
450 540 : staForm = (Form_pg_statistic_ext) GETSTRUCT(htup);
451 540 : entry->statOid = staForm->oid;
452 540 : entry->schema = get_namespace_name(staForm->stxnamespace);
453 540 : entry->name = pstrdup(NameStr(staForm->stxname));
454 1432 : for (i = 0; i < staForm->stxkeys.dim1; i++)
455 : {
456 892 : entry->columns = bms_add_member(entry->columns,
457 892 : staForm->stxkeys.values[i]);
458 : }
459 :
460 540 : datum = SysCacheGetAttr(STATEXTOID, htup, Anum_pg_statistic_ext_stxstattarget, &isnull);
461 540 : entry->stattarget = isnull ? -1 : DatumGetInt16(datum);
462 :
463 : /* decode the stxkind char array into a list of chars */
464 540 : datum = SysCacheGetAttrNotNull(STATEXTOID, htup,
465 : Anum_pg_statistic_ext_stxkind);
466 540 : arr = DatumGetArrayTypeP(datum);
467 540 : if (ARR_NDIM(arr) != 1 ||
468 540 : ARR_HASNULL(arr) ||
469 540 : ARR_ELEMTYPE(arr) != CHAROID)
470 0 : elog(ERROR, "stxkind is not a 1-D char array");
471 540 : enabled = (char *) ARR_DATA_PTR(arr);
472 1568 : for (i = 0; i < ARR_DIMS(arr)[0]; i++)
473 : {
474 : Assert((enabled[i] == STATS_EXT_NDISTINCT) ||
475 : (enabled[i] == STATS_EXT_DEPENDENCIES) ||
476 : (enabled[i] == STATS_EXT_MCV) ||
477 : (enabled[i] == STATS_EXT_EXPRESSIONS));
478 1028 : entry->types = lappend_int(entry->types, (int) enabled[i]);
479 : }
480 :
481 : /* decode expression (if any) */
482 540 : datum = SysCacheGetAttr(STATEXTOID, htup,
483 : Anum_pg_statistic_ext_stxexprs, &isnull);
484 :
485 540 : if (!isnull)
486 : {
487 : char *exprsString;
488 :
489 230 : exprsString = TextDatumGetCString(datum);
490 230 : exprs = (List *) stringToNode(exprsString);
491 :
492 230 : pfree(exprsString);
493 :
494 : /*
495 : * Run the expressions through eval_const_expressions. This is not
496 : * just an optimization, but is necessary, because the planner
497 : * will be comparing them to similarly-processed qual clauses, and
498 : * may fail to detect valid matches without this. We must not use
499 : * canonicalize_qual, however, since these aren't qual
500 : * expressions.
501 : */
502 230 : exprs = (List *) eval_const_expressions(NULL, (Node *) exprs);
503 :
504 : /* May as well fix opfuncids too */
505 230 : fix_opfuncids((Node *) exprs);
506 : }
507 :
508 540 : entry->exprs = exprs;
509 :
510 540 : result = lappend(result, entry);
511 : }
512 :
513 14122 : systable_endscan(scan);
514 :
515 14122 : return result;
516 : }
517 :
518 : /*
519 : * examine_attribute -- pre-analysis of a single column
520 : *
521 : * Determine whether the column is analyzable; if so, create and initialize
522 : * a VacAttrStats struct for it. If not, return NULL.
523 : */
524 : static VacAttrStats *
525 422 : examine_attribute(Node *expr)
526 : {
527 : HeapTuple typtuple;
528 : VacAttrStats *stats;
529 : int i;
530 : bool ok;
531 :
532 : /*
533 : * Create the VacAttrStats struct.
534 : */
535 422 : stats = palloc0_object(VacAttrStats);
536 422 : stats->attstattarget = -1;
537 :
538 : /*
539 : * When analyzing an expression, believe the expression tree's type not
540 : * the column datatype --- the latter might be the opckeytype storage type
541 : * of the opclass, which is not interesting for our purposes. (Note: if
542 : * we did anything with non-expression statistics columns, we'd need to
543 : * figure out where to get the correct type info from, but for now that's
544 : * not a problem.) It's not clear whether anyone will care about the
545 : * typmod, but we store that too just in case.
546 : */
547 422 : stats->attrtypid = exprType(expr);
548 422 : stats->attrtypmod = exprTypmod(expr);
549 422 : stats->attrcollid = exprCollation(expr);
550 :
551 422 : typtuple = SearchSysCacheCopy1(TYPEOID,
552 : ObjectIdGetDatum(stats->attrtypid));
553 422 : if (!HeapTupleIsValid(typtuple))
554 0 : elog(ERROR, "cache lookup failed for type %u", stats->attrtypid);
555 422 : stats->attrtype = (Form_pg_type) GETSTRUCT(typtuple);
556 :
557 : /*
558 : * We don't actually analyze individual attributes, so no need to set the
559 : * memory context.
560 : */
561 422 : stats->anl_context = NULL;
562 422 : stats->tupattnum = InvalidAttrNumber;
563 :
564 : /*
565 : * The fields describing the stats->stavalues[n] element types default to
566 : * the type of the data being analyzed, but the type-specific typanalyze
567 : * function can change them if it wants to store something else.
568 : */
569 2532 : for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
570 : {
571 2110 : stats->statypid[i] = stats->attrtypid;
572 2110 : stats->statyplen[i] = stats->attrtype->typlen;
573 2110 : stats->statypbyval[i] = stats->attrtype->typbyval;
574 2110 : stats->statypalign[i] = stats->attrtype->typalign;
575 : }
576 :
577 : /*
578 : * Call the type-specific typanalyze function. If none is specified, use
579 : * std_typanalyze().
580 : */
581 422 : if (OidIsValid(stats->attrtype->typanalyze))
582 10 : ok = DatumGetBool(OidFunctionCall1(stats->attrtype->typanalyze,
583 : PointerGetDatum(stats)));
584 : else
585 412 : ok = std_typanalyze(stats);
586 :
587 422 : if (!ok || stats->compute_stats == NULL || stats->minrows <= 0)
588 : {
589 2 : heap_freetuple(typtuple);
590 2 : pfree(stats);
591 2 : return NULL;
592 : }
593 :
594 420 : return stats;
595 : }
596 :
597 : /*
598 : * examine_expression -- pre-analysis of a single expression
599 : *
600 : * Determine whether the expression is analyzable; if so, create and initialize
601 : * a VacAttrStats struct for it. If not, return NULL.
602 : */
603 : static VacAttrStats *
604 420 : examine_expression(Node *expr, int stattarget)
605 : {
606 : HeapTuple typtuple;
607 : VacAttrStats *stats;
608 : int i;
609 : bool ok;
610 :
611 : Assert(expr != NULL);
612 :
613 : /*
614 : * Create the VacAttrStats struct.
615 : */
616 420 : stats = palloc0_object(VacAttrStats);
617 :
618 : /*
619 : * We can't have statistics target specified for the expression, so we
620 : * could use either the default_statistics_target, or the target computed
621 : * for the extended statistics. The second option seems more reasonable.
622 : */
623 420 : stats->attstattarget = stattarget;
624 :
625 : /*
626 : * When analyzing an expression, believe the expression tree's type.
627 : */
628 420 : stats->attrtypid = exprType(expr);
629 420 : stats->attrtypmod = exprTypmod(expr);
630 :
631 : /*
632 : * We don't allow collation to be specified in CREATE STATISTICS, so we
633 : * have to use the collation specified for the expression. It's possible
634 : * to specify the collation in the expression "(col COLLATE "en_US")" in
635 : * which case exprCollation() does the right thing.
636 : */
637 420 : stats->attrcollid = exprCollation(expr);
638 :
639 420 : typtuple = SearchSysCacheCopy1(TYPEOID,
640 : ObjectIdGetDatum(stats->attrtypid));
641 420 : if (!HeapTupleIsValid(typtuple))
642 0 : elog(ERROR, "cache lookup failed for type %u", stats->attrtypid);
643 :
644 420 : stats->attrtype = (Form_pg_type) GETSTRUCT(typtuple);
645 420 : stats->anl_context = CurrentMemoryContext; /* XXX should be using
646 : * something else? */
647 420 : stats->tupattnum = InvalidAttrNumber;
648 :
649 : /*
650 : * The fields describing the stats->stavalues[n] element types default to
651 : * the type of the data being analyzed, but the type-specific typanalyze
652 : * function can change them if it wants to store something else.
653 : */
654 2520 : for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
655 : {
656 2100 : stats->statypid[i] = stats->attrtypid;
657 2100 : stats->statyplen[i] = stats->attrtype->typlen;
658 2100 : stats->statypbyval[i] = stats->attrtype->typbyval;
659 2100 : stats->statypalign[i] = stats->attrtype->typalign;
660 : }
661 :
662 : /*
663 : * Call the type-specific typanalyze function. If none is specified, use
664 : * std_typanalyze().
665 : */
666 420 : if (OidIsValid(stats->attrtype->typanalyze))
667 8 : ok = DatumGetBool(OidFunctionCall1(stats->attrtype->typanalyze,
668 : PointerGetDatum(stats)));
669 : else
670 412 : ok = std_typanalyze(stats);
671 :
672 420 : if (!ok || stats->compute_stats == NULL || stats->minrows <= 0)
673 : {
674 0 : heap_freetuple(typtuple);
675 0 : pfree(stats);
676 0 : return NULL;
677 : }
678 :
679 420 : return stats;
680 : }
681 :
682 : /*
683 : * Using 'vacatts' of size 'nvacatts' as input data, return a newly-built
684 : * VacAttrStats array which includes only the items corresponding to
685 : * attributes indicated by 'attrs'. If we don't have all of the per-column
686 : * stats available to compute the extended stats, then we return NULL to
687 : * indicate to the caller that the stats should not be built.
688 : */
689 : static VacAttrStats **
690 540 : lookup_var_attr_stats(Bitmapset *attrs, List *exprs,
691 : int nvacatts, VacAttrStats **vacatts)
692 : {
693 540 : int i = 0;
694 540 : int x = -1;
695 : int natts;
696 : VacAttrStats **stats;
697 : ListCell *lc;
698 :
699 540 : natts = bms_num_members(attrs) + list_length(exprs);
700 :
701 540 : stats = (VacAttrStats **) palloc(natts * sizeof(VacAttrStats *));
702 :
703 : /* lookup VacAttrStats info for the requested columns (same attnum) */
704 1412 : while ((x = bms_next_member(attrs, x)) >= 0)
705 : {
706 : int j;
707 :
708 886 : stats[i] = NULL;
709 2528 : for (j = 0; j < nvacatts; j++)
710 : {
711 2514 : if (x == vacatts[j]->tupattnum)
712 : {
713 872 : stats[i] = vacatts[j];
714 872 : break;
715 : }
716 : }
717 :
718 886 : if (!stats[i])
719 : {
720 : /*
721 : * Looks like stats were not gathered for one of the columns
722 : * required. We'll be unable to build the extended stats without
723 : * this column.
724 : */
725 14 : pfree(stats);
726 14 : return NULL;
727 : }
728 :
729 872 : i++;
730 : }
731 :
732 : /* also add info for expressions */
733 946 : foreach(lc, exprs)
734 : {
735 422 : Node *expr = (Node *) lfirst(lc);
736 :
737 422 : stats[i] = examine_attribute(expr);
738 :
739 : /*
740 : * If the expression has been found as non-analyzable, give up. We
741 : * will not be able to build extended stats with it.
742 : */
743 422 : if (stats[i] == NULL)
744 : {
745 2 : pfree(stats);
746 2 : return NULL;
747 : }
748 :
749 : /*
750 : * XXX We need tuple descriptor later, and we just grab it from
751 : * stats[0]->tupDesc (see e.g. statext_mcv_build). But as coded
752 : * examine_attribute does not set that, so just grab it from the first
753 : * vacatts element.
754 : */
755 420 : stats[i]->tupDesc = vacatts[0]->tupDesc;
756 :
757 420 : i++;
758 : }
759 :
760 524 : return stats;
761 : }
762 :
763 : /*
764 : * statext_store
765 : * Serializes the statistics and stores them into the pg_statistic_ext_data
766 : * tuple.
767 : */
768 : static void
769 259 : statext_store(Oid statOid, bool inh,
770 : MVNDistinct *ndistinct, MVDependencies *dependencies,
771 : MCVList *mcv, Datum exprs, VacAttrStats **stats)
772 : {
773 : Relation pg_stextdata;
774 : HeapTuple stup;
775 : Datum values[Natts_pg_statistic_ext_data];
776 : bool nulls[Natts_pg_statistic_ext_data];
777 :
778 259 : pg_stextdata = table_open(StatisticExtDataRelationId, RowExclusiveLock);
779 :
780 259 : memset(nulls, true, sizeof(nulls));
781 259 : memset(values, 0, sizeof(values));
782 :
783 : /* basic info */
784 259 : values[Anum_pg_statistic_ext_data_stxoid - 1] = ObjectIdGetDatum(statOid);
785 259 : nulls[Anum_pg_statistic_ext_data_stxoid - 1] = false;
786 :
787 259 : values[Anum_pg_statistic_ext_data_stxdinherit - 1] = BoolGetDatum(inh);
788 259 : nulls[Anum_pg_statistic_ext_data_stxdinherit - 1] = false;
789 :
790 : /*
791 : * Construct a new pg_statistic_ext_data tuple, replacing the calculated
792 : * stats.
793 : */
794 259 : if (ndistinct != NULL)
795 : {
796 127 : bytea *data = statext_ndistinct_serialize(ndistinct);
797 :
798 127 : nulls[Anum_pg_statistic_ext_data_stxdndistinct - 1] = (data == NULL);
799 127 : values[Anum_pg_statistic_ext_data_stxdndistinct - 1] = PointerGetDatum(data);
800 : }
801 :
802 259 : if (dependencies != NULL)
803 : {
804 91 : bytea *data = statext_dependencies_serialize(dependencies);
805 :
806 91 : nulls[Anum_pg_statistic_ext_data_stxddependencies - 1] = (data == NULL);
807 91 : values[Anum_pg_statistic_ext_data_stxddependencies - 1] = PointerGetDatum(data);
808 : }
809 259 : if (mcv != NULL)
810 : {
811 139 : bytea *data = statext_mcv_serialize(mcv, stats);
812 :
813 139 : nulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = (data == NULL);
814 139 : values[Anum_pg_statistic_ext_data_stxdmcv - 1] = PointerGetDatum(data);
815 : }
816 259 : if (exprs != (Datum) 0)
817 : {
818 114 : nulls[Anum_pg_statistic_ext_data_stxdexpr - 1] = false;
819 114 : values[Anum_pg_statistic_ext_data_stxdexpr - 1] = exprs;
820 : }
821 :
822 : /*
823 : * Delete the old tuple if it exists, and insert a new one. It's easier
824 : * than trying to update or insert, based on various conditions.
825 : */
826 259 : RemoveStatisticsDataById(statOid, inh);
827 :
828 : /* form and insert a new tuple */
829 259 : stup = heap_form_tuple(RelationGetDescr(pg_stextdata), values, nulls);
830 259 : CatalogTupleInsert(pg_stextdata, stup);
831 :
832 259 : heap_freetuple(stup);
833 :
834 259 : table_close(pg_stextdata, RowExclusiveLock);
835 259 : }
836 :
837 : /* initialize multi-dimensional sort */
838 : MultiSortSupport
839 1042 : multi_sort_init(int ndims)
840 : {
841 : MultiSortSupport mss;
842 :
843 : Assert(ndims >= 2);
844 :
845 1042 : mss = (MultiSortSupport) palloc0(offsetof(MultiSortSupportData, ssup)
846 1042 : + sizeof(SortSupportData) * ndims);
847 :
848 1042 : mss->ndims = ndims;
849 :
850 1042 : return mss;
851 : }
852 :
853 : /*
854 : * Prepare sort support info using the given sort operator and collation
855 : * at the position 'sortdim'
856 : */
857 : void
858 2495 : multi_sort_add_dimension(MultiSortSupport mss, int sortdim,
859 : Oid oper, Oid collation)
860 : {
861 2495 : SortSupport ssup = &mss->ssup[sortdim];
862 :
863 2495 : ssup->ssup_cxt = CurrentMemoryContext;
864 2495 : ssup->ssup_collation = collation;
865 2495 : ssup->ssup_nulls_first = false;
866 :
867 2495 : PrepareSortSupportFromOrderingOp(oper, ssup);
868 2495 : }
869 :
870 : /* compare all the dimensions in the selected order */
871 : int
872 11080870 : multi_sort_compare(const void *a, const void *b, void *arg)
873 : {
874 11080870 : MultiSortSupport mss = (MultiSortSupport) arg;
875 11080870 : const SortItem *ia = a;
876 11080870 : const SortItem *ib = b;
877 : int i;
878 :
879 19621051 : for (i = 0; i < mss->ndims; i++)
880 : {
881 : int compare;
882 :
883 17546083 : compare = ApplySortComparator(ia->values[i], ia->isnull[i],
884 17546083 : ib->values[i], ib->isnull[i],
885 17546083 : &mss->ssup[i]);
886 :
887 17546083 : if (compare != 0)
888 9005902 : return compare;
889 : }
890 :
891 : /* equal by default */
892 2074968 : return 0;
893 : }
894 :
895 : /* compare selected dimension */
896 : int
897 736575 : multi_sort_compare_dim(int dim, const SortItem *a, const SortItem *b,
898 : MultiSortSupport mss)
899 : {
900 1473150 : return ApplySortComparator(a->values[dim], a->isnull[dim],
901 736575 : b->values[dim], b->isnull[dim],
902 736575 : &mss->ssup[dim]);
903 : }
904 :
905 : int
906 753337 : multi_sort_compare_dims(int start, int end,
907 : const SortItem *a, const SortItem *b,
908 : MultiSortSupport mss)
909 : {
910 : int dim;
911 :
912 1703191 : for (dim = start; dim <= end; dim++)
913 : {
914 966616 : int r = ApplySortComparator(a->values[dim], a->isnull[dim],
915 966616 : b->values[dim], b->isnull[dim],
916 966616 : &mss->ssup[dim]);
917 :
918 966616 : if (r != 0)
919 16762 : return r;
920 : }
921 :
922 736575 : return 0;
923 : }
924 :
925 : int
926 104594 : compare_scalars_simple(const void *a, const void *b, void *arg)
927 : {
928 104594 : return compare_datums_simple(*(const Datum *) a,
929 : *(const Datum *) b,
930 : (SortSupport) arg);
931 : }
932 :
933 : int
934 118606 : compare_datums_simple(Datum a, Datum b, SortSupport ssup)
935 : {
936 118606 : return ApplySortComparator(a, false, b, false, ssup);
937 : }
938 :
939 : /*
940 : * build_attnums_array
941 : * Transforms a bitmap into an array of AttrNumber values.
942 : *
943 : * This is used for extended statistics only, so all the attributes must be
944 : * user-defined. That means offsetting by FirstLowInvalidHeapAttributeNumber
945 : * is not necessary here (and when querying the bitmap).
946 : */
947 : AttrNumber *
948 0 : build_attnums_array(Bitmapset *attrs, int nexprs, int *numattrs)
949 : {
950 : int i,
951 : j;
952 : AttrNumber *attnums;
953 0 : int num = bms_num_members(attrs);
954 :
955 0 : if (numattrs)
956 0 : *numattrs = num;
957 :
958 : /* build attnums from the bitmapset */
959 0 : attnums = palloc_array(AttrNumber, num);
960 0 : i = 0;
961 0 : j = -1;
962 0 : while ((j = bms_next_member(attrs, j)) >= 0)
963 : {
964 0 : int attnum = (j - nexprs);
965 :
966 : /*
967 : * Make sure the bitmap contains only user-defined attributes. As
968 : * bitmaps can't contain negative values, this can be violated in two
969 : * ways. Firstly, the bitmap might contain 0 as a member, and secondly
970 : * the integer value might be larger than MaxAttrNumber.
971 : */
972 : Assert(AttributeNumberIsValid(attnum));
973 : Assert(attnum <= MaxAttrNumber);
974 : Assert(attnum >= (-nexprs));
975 :
976 0 : attnums[i++] = (AttrNumber) attnum;
977 :
978 : /* protect against overflows */
979 : Assert(i <= num);
980 : }
981 :
982 0 : return attnums;
983 : }
984 :
985 : /*
986 : * build_sorted_items
987 : * build a sorted array of SortItem with values from rows
988 : *
989 : * Note: All the memory is allocated in a single chunk, so that the caller
990 : * can simply pfree the return value to release all of it.
991 : */
992 : SortItem *
993 663 : build_sorted_items(StatsBuildData *data, int *nitems,
994 : MultiSortSupport mss,
995 : int numattrs, AttrNumber *attnums)
996 : {
997 : int i,
998 : j,
999 : nrows;
1000 663 : int nvalues = data->numrows * numattrs;
1001 : Size len;
1002 : SortItem *items;
1003 : Datum *values;
1004 : bool *isnull;
1005 : char *ptr;
1006 : int *typlen;
1007 :
1008 : /* Compute the total amount of memory we need (both items and values). */
1009 663 : len = MAXALIGN(data->numrows * sizeof(SortItem)) +
1010 663 : nvalues * (sizeof(Datum) + sizeof(bool));
1011 :
1012 : /* Allocate the memory and split it into the pieces. */
1013 663 : ptr = palloc0(len);
1014 :
1015 : /* items to sort */
1016 663 : items = (SortItem *) ptr;
1017 : /* MAXALIGN ensures that the following Datums are suitably aligned */
1018 663 : ptr += MAXALIGN(data->numrows * sizeof(SortItem));
1019 :
1020 : /* values and null flags */
1021 663 : values = (Datum *) ptr;
1022 663 : ptr += nvalues * sizeof(Datum);
1023 :
1024 663 : isnull = (bool *) ptr;
1025 663 : ptr += nvalues * sizeof(bool);
1026 :
1027 : /* make sure we consumed the whole buffer exactly */
1028 : Assert((ptr - (char *) items) == len);
1029 :
1030 : /* fix the pointers to Datum and bool arrays */
1031 663 : nrows = 0;
1032 996462 : for (i = 0; i < data->numrows; i++)
1033 : {
1034 995799 : items[nrows].values = &values[nrows * numattrs];
1035 995799 : items[nrows].isnull = &isnull[nrows * numattrs];
1036 :
1037 995799 : nrows++;
1038 : }
1039 :
1040 : /* build a local cache of typlen for all attributes */
1041 663 : typlen = palloc_array(int, data->nattnums);
1042 2628 : for (i = 0; i < data->nattnums; i++)
1043 1965 : typlen[i] = get_typlen(data->stats[i]->attrtypid);
1044 :
1045 663 : nrows = 0;
1046 996462 : for (i = 0; i < data->numrows; i++)
1047 : {
1048 995799 : bool toowide = false;
1049 :
1050 : /* load the values/null flags from sample rows */
1051 3426213 : for (j = 0; j < numattrs; j++)
1052 : {
1053 : Datum value;
1054 : bool isnull;
1055 : int attlen;
1056 2430414 : AttrNumber attnum = attnums[j];
1057 :
1058 : int idx;
1059 :
1060 : /* match attnum to the pre-calculated data */
1061 4790955 : for (idx = 0; idx < data->nattnums; idx++)
1062 : {
1063 4790955 : if (attnum == data->attnums[idx])
1064 2430414 : break;
1065 : }
1066 :
1067 : Assert(idx < data->nattnums);
1068 :
1069 2430414 : value = data->values[idx][i];
1070 2430414 : isnull = data->nulls[idx][i];
1071 2430414 : attlen = typlen[idx];
1072 :
1073 : /*
1074 : * If this is a varlena value, check if it's too wide and if yes
1075 : * then skip the whole item. Otherwise detoast the value.
1076 : *
1077 : * XXX It may happen that we've already detoasted some preceding
1078 : * values for the current item. We don't bother to cleanup those
1079 : * on the assumption that those are small (below WIDTH_THRESHOLD)
1080 : * and will be discarded at the end of analyze.
1081 : */
1082 2430414 : if ((!isnull) && (attlen == -1))
1083 : {
1084 741282 : if (toast_raw_datum_size(value) > WIDTH_THRESHOLD)
1085 : {
1086 0 : toowide = true;
1087 0 : break;
1088 : }
1089 :
1090 741282 : value = PointerGetDatum(PG_DETOAST_DATUM(value));
1091 : }
1092 :
1093 2430414 : items[nrows].values[j] = value;
1094 2430414 : items[nrows].isnull[j] = isnull;
1095 : }
1096 :
1097 995799 : if (toowide)
1098 0 : continue;
1099 :
1100 995799 : nrows++;
1101 : }
1102 :
1103 : /* store the actual number of items (ignoring the too-wide ones) */
1104 663 : *nitems = nrows;
1105 :
1106 : /* all items were too wide */
1107 663 : if (nrows == 0)
1108 : {
1109 : /* everything is allocated as a single chunk */
1110 0 : pfree(items);
1111 0 : return NULL;
1112 : }
1113 :
1114 : /* do the sort, using the multi-sort */
1115 663 : qsort_interruptible(items, nrows, sizeof(SortItem),
1116 : multi_sort_compare, mss);
1117 :
1118 663 : return items;
1119 : }
1120 :
1121 : /*
1122 : * has_stats_of_kind
1123 : * Check whether the list contains statistic of a given kind
1124 : */
1125 : bool
1126 2514 : has_stats_of_kind(List *stats, char requiredkind)
1127 : {
1128 : ListCell *l;
1129 :
1130 4143 : foreach(l, stats)
1131 : {
1132 2895 : StatisticExtInfo *stat = (StatisticExtInfo *) lfirst(l);
1133 :
1134 2895 : if (stat->kind == requiredkind)
1135 1266 : return true;
1136 : }
1137 :
1138 1248 : return false;
1139 : }
1140 :
1141 : /*
1142 : * stat_find_expression
1143 : * Search for an expression in statistics object's list of expressions.
1144 : *
1145 : * Returns the index of the expression in the statistics object's list of
1146 : * expressions, or -1 if not found.
1147 : */
1148 : static int
1149 297 : stat_find_expression(StatisticExtInfo *stat, Node *expr)
1150 : {
1151 : ListCell *lc;
1152 : int idx;
1153 :
1154 297 : idx = 0;
1155 537 : foreach(lc, stat->exprs)
1156 : {
1157 486 : Node *stat_expr = (Node *) lfirst(lc);
1158 :
1159 486 : if (equal(stat_expr, expr))
1160 246 : return idx;
1161 240 : idx++;
1162 : }
1163 :
1164 : /* Expression not found */
1165 51 : return -1;
1166 : }
1167 :
1168 : /*
1169 : * stat_covers_expressions
1170 : * Test whether a statistics object covers all expressions in a list.
1171 : *
1172 : * Returns true if all expressions are covered. If expr_idxs is non-NULL, it
1173 : * is populated with the indexes of the expressions found.
1174 : */
1175 : static bool
1176 1557 : stat_covers_expressions(StatisticExtInfo *stat, List *exprs,
1177 : Bitmapset **expr_idxs)
1178 : {
1179 : ListCell *lc;
1180 :
1181 1803 : foreach(lc, exprs)
1182 : {
1183 297 : Node *expr = (Node *) lfirst(lc);
1184 : int expr_idx;
1185 :
1186 297 : expr_idx = stat_find_expression(stat, expr);
1187 297 : if (expr_idx == -1)
1188 51 : return false;
1189 :
1190 246 : if (expr_idxs != NULL)
1191 123 : *expr_idxs = bms_add_member(*expr_idxs, expr_idx);
1192 : }
1193 :
1194 : /* If we reach here, all expressions are covered */
1195 1506 : return true;
1196 : }
1197 :
1198 : /*
1199 : * choose_best_statistics
1200 : * Look for and return statistics with the specified 'requiredkind' which
1201 : * have keys that match at least two of the given attnums. Return NULL if
1202 : * there's no match.
1203 : *
1204 : * The current selection criteria is very simple - we choose the statistics
1205 : * object referencing the most attributes in covered (and still unestimated
1206 : * clauses), breaking ties in favor of objects with fewer keys overall.
1207 : *
1208 : * The clause_attnums is an array of bitmaps, storing attnums for individual
1209 : * clauses. A NULL element means the clause is either incompatible or already
1210 : * estimated.
1211 : *
1212 : * XXX If multiple statistics objects tie on both criteria, then which object
1213 : * is chosen depends on the order that they appear in the stats list. Perhaps
1214 : * further tiebreakers are needed.
1215 : */
1216 : StatisticExtInfo *
1217 675 : choose_best_statistics(List *stats, char requiredkind, bool inh,
1218 : Bitmapset **clause_attnums, List **clause_exprs,
1219 : int nclauses)
1220 : {
1221 : ListCell *lc;
1222 675 : StatisticExtInfo *best_match = NULL;
1223 675 : int best_num_matched = 2; /* goal #1: maximize */
1224 675 : int best_match_keys = (STATS_MAX_DIMENSIONS + 1); /* goal #2: minimize */
1225 :
1226 1773 : foreach(lc, stats)
1227 : {
1228 : int i;
1229 1098 : StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
1230 1098 : Bitmapset *matched_attnums = NULL;
1231 1098 : Bitmapset *matched_exprs = NULL;
1232 : int num_matched;
1233 : int numkeys;
1234 :
1235 : /* skip statistics that are not of the correct type */
1236 1098 : if (info->kind != requiredkind)
1237 234 : continue;
1238 :
1239 : /* skip statistics with mismatching inheritance flag */
1240 864 : if (info->inherit != inh)
1241 12 : continue;
1242 :
1243 : /*
1244 : * Collect attributes and expressions in remaining (unestimated)
1245 : * clauses fully covered by this statistic object.
1246 : *
1247 : * We know already estimated clauses have both clause_attnums and
1248 : * clause_exprs set to NULL. We leave the pointers NULL if already
1249 : * estimated, or we reset them to NULL after estimating the clause.
1250 : */
1251 2898 : for (i = 0; i < nclauses; i++)
1252 : {
1253 2046 : Bitmapset *expr_idxs = NULL;
1254 :
1255 : /* ignore incompatible/estimated clauses */
1256 2046 : if (!clause_attnums[i] && !clause_exprs[i])
1257 1242 : continue;
1258 :
1259 : /* ignore clauses that are not covered by this object */
1260 1017 : if (!bms_is_subset(clause_attnums[i], info->keys) ||
1261 852 : !stat_covers_expressions(info, clause_exprs[i], &expr_idxs))
1262 213 : continue;
1263 :
1264 : /* record attnums and indexes of expressions covered */
1265 804 : matched_attnums = bms_add_members(matched_attnums, clause_attnums[i]);
1266 804 : matched_exprs = bms_add_members(matched_exprs, expr_idxs);
1267 : }
1268 :
1269 852 : num_matched = bms_num_members(matched_attnums) + bms_num_members(matched_exprs);
1270 :
1271 852 : bms_free(matched_attnums);
1272 852 : bms_free(matched_exprs);
1273 :
1274 : /*
1275 : * save the actual number of keys in the stats so that we can choose
1276 : * the narrowest stats with the most matching keys.
1277 : */
1278 852 : numkeys = bms_num_members(info->keys) + list_length(info->exprs);
1279 :
1280 : /*
1281 : * Use this object when it increases the number of matched attributes
1282 : * and expressions or when it matches the same number of attributes
1283 : * and expressions but these stats have fewer keys than any previous
1284 : * match.
1285 : */
1286 852 : if (num_matched > best_num_matched ||
1287 207 : (num_matched == best_num_matched && numkeys < best_match_keys))
1288 : {
1289 303 : best_match = info;
1290 303 : best_num_matched = num_matched;
1291 303 : best_match_keys = numkeys;
1292 : }
1293 : }
1294 :
1295 675 : return best_match;
1296 : }
1297 :
1298 : /*
1299 : * statext_is_compatible_clause_internal
1300 : * Determines if the clause is compatible with MCV lists.
1301 : *
1302 : * To be compatible, the given clause must be a combination of supported
1303 : * clauses built from Vars or sub-expressions (where a sub-expression is
1304 : * something that exactly matches an expression found in statistics objects).
1305 : * This function recursively examines the clause and extracts any
1306 : * sub-expressions that will need to be matched against statistics.
1307 : *
1308 : * Currently, we only support the following types of clauses:
1309 : *
1310 : * (a) OpExprs of the form (Var/Expr op Const), or (Const op Var/Expr), where
1311 : * the op is one of ("=", "<", ">", ">=", "<=")
1312 : *
1313 : * (b) (Var/Expr IS [NOT] NULL)
1314 : *
1315 : * (c) combinations using AND/OR/NOT
1316 : *
1317 : * (d) ScalarArrayOpExprs of the form (Var/Expr op ANY (Const)) or
1318 : * (Var/Expr op ALL (Const))
1319 : *
1320 : * In the future, the range of supported clauses may be expanded to more
1321 : * complex cases, for example (Var op Var).
1322 : *
1323 : * Arguments:
1324 : * clause: (sub)clause to be inspected (bare clause, not a RestrictInfo)
1325 : * relid: rel that all Vars in clause must belong to
1326 : * *attnums: input/output parameter collecting attribute numbers of all
1327 : * mentioned Vars. Note that we do not offset the attribute numbers,
1328 : * so we can't cope with system columns.
1329 : * *exprs: input/output parameter collecting primitive subclauses within
1330 : * the clause tree
1331 : * *leakproof: input/output parameter recording the leakproofness of the
1332 : * clause tree. This should be true initially, and will be set to false
1333 : * if any operator function used in an OpExpr is not leakproof.
1334 : *
1335 : * Returns false if there is something we definitively can't handle.
1336 : * On true return, we can proceed to match the *exprs against statistics.
1337 : */
1338 : static bool
1339 1731 : statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
1340 : Index relid, Bitmapset **attnums,
1341 : List **exprs, bool *leakproof)
1342 : {
1343 : /* Look inside any binary-compatible relabeling (as in examine_variable) */
1344 1731 : if (IsA(clause, RelabelType))
1345 0 : clause = (Node *) ((RelabelType *) clause)->arg;
1346 :
1347 : /* plain Var references (boolean Vars or recursive checks) */
1348 1731 : if (IsA(clause, Var))
1349 : {
1350 774 : Var *var = (Var *) clause;
1351 :
1352 : /* Ensure var is from the correct relation */
1353 774 : if (var->varno != relid)
1354 0 : return false;
1355 :
1356 : /* we also better ensure the Var is from the current level */
1357 774 : if (var->varlevelsup > 0)
1358 0 : return false;
1359 :
1360 : /*
1361 : * Also reject system attributes and whole-row Vars (we don't allow
1362 : * stats on those).
1363 : */
1364 774 : if (!AttrNumberIsForUserDefinedAttr(var->varattno))
1365 0 : return false;
1366 :
1367 : /* OK, record the attnum for later permissions checks. */
1368 774 : *attnums = bms_add_member(*attnums, var->varattno);
1369 :
1370 774 : return true;
1371 : }
1372 :
1373 : /* (Var/Expr op Const) or (Const op Var/Expr) */
1374 957 : if (is_opclause(clause))
1375 : {
1376 696 : OpExpr *expr = (OpExpr *) clause;
1377 : Node *clause_expr;
1378 :
1379 : /* Only expressions with two arguments are considered compatible. */
1380 696 : if (list_length(expr->args) != 2)
1381 0 : return false;
1382 :
1383 : /* Check if the expression has the right shape */
1384 696 : if (!examine_opclause_args(expr->args, &clause_expr, NULL, NULL))
1385 0 : return false;
1386 :
1387 : /*
1388 : * If it's not one of the supported operators ("=", "<", ">", etc.),
1389 : * just ignore the clause, as it's not compatible with MCV lists.
1390 : *
1391 : * This uses the function for estimating selectivity, not the operator
1392 : * directly (a bit awkward, but well ...).
1393 : */
1394 696 : switch (get_oprrest(expr->opno))
1395 : {
1396 696 : case F_EQSEL:
1397 : case F_NEQSEL:
1398 : case F_SCALARLTSEL:
1399 : case F_SCALARLESEL:
1400 : case F_SCALARGTSEL:
1401 : case F_SCALARGESEL:
1402 : /* supported, will continue with inspection of the Var/Expr */
1403 696 : break;
1404 :
1405 0 : default:
1406 : /* other estimators are considered unknown/unsupported */
1407 0 : return false;
1408 : }
1409 :
1410 : /* Check if the operator is leakproof */
1411 696 : if (*leakproof)
1412 690 : *leakproof = get_func_leakproof(get_opcode(expr->opno));
1413 :
1414 : /* Check (Var op Const) or (Const op Var) clauses by recursing. */
1415 696 : if (IsA(clause_expr, Var))
1416 576 : return statext_is_compatible_clause_internal(root, clause_expr,
1417 : relid, attnums,
1418 : exprs, leakproof);
1419 :
1420 : /* Otherwise we have (Expr op Const) or (Const op Expr). */
1421 120 : *exprs = lappend(*exprs, clause_expr);
1422 120 : return true;
1423 : }
1424 :
1425 : /* Var/Expr IN Array */
1426 261 : if (IsA(clause, ScalarArrayOpExpr))
1427 : {
1428 144 : ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) clause;
1429 : Node *clause_expr;
1430 : bool expronleft;
1431 :
1432 : /* Only expressions with two arguments are considered compatible. */
1433 144 : if (list_length(expr->args) != 2)
1434 0 : return false;
1435 :
1436 : /* Check if the expression has the right shape (one Var, one Const) */
1437 144 : if (!examine_opclause_args(expr->args, &clause_expr, NULL, &expronleft))
1438 0 : return false;
1439 :
1440 : /* We only support Var on left, Const on right */
1441 144 : if (!expronleft)
1442 3 : return false;
1443 :
1444 : /*
1445 : * If it's not one of the supported operators ("=", "<", ">", etc.),
1446 : * just ignore the clause, as it's not compatible with MCV lists.
1447 : *
1448 : * This uses the function for estimating selectivity, not the operator
1449 : * directly (a bit awkward, but well ...).
1450 : */
1451 141 : switch (get_oprrest(expr->opno))
1452 : {
1453 141 : case F_EQSEL:
1454 : case F_NEQSEL:
1455 : case F_SCALARLTSEL:
1456 : case F_SCALARLESEL:
1457 : case F_SCALARGTSEL:
1458 : case F_SCALARGESEL:
1459 : /* supported, will continue with inspection of the Var/Expr */
1460 141 : break;
1461 :
1462 0 : default:
1463 : /* other estimators are considered unknown/unsupported */
1464 0 : return false;
1465 : }
1466 :
1467 : /* Check if the operator is leakproof */
1468 141 : if (*leakproof)
1469 141 : *leakproof = get_func_leakproof(get_opcode(expr->opno));
1470 :
1471 : /* Check Var IN Array clauses by recursing. */
1472 141 : if (IsA(clause_expr, Var))
1473 114 : return statext_is_compatible_clause_internal(root, clause_expr,
1474 : relid, attnums,
1475 : exprs, leakproof);
1476 :
1477 : /* Otherwise we have Expr IN Array. */
1478 27 : *exprs = lappend(*exprs, clause_expr);
1479 27 : return true;
1480 : }
1481 :
1482 : /* AND/OR/NOT clause */
1483 234 : if (is_andclause(clause) ||
1484 207 : is_orclause(clause) ||
1485 90 : is_notclause(clause))
1486 : {
1487 : /*
1488 : * AND/OR/NOT-clauses are supported if all sub-clauses are supported
1489 : *
1490 : * Perhaps we could improve this by handling mixed cases, when some of
1491 : * the clauses are supported and some are not. Selectivity for the
1492 : * supported subclauses would be computed using extended statistics,
1493 : * and the remaining clauses would be estimated using the traditional
1494 : * algorithm (product of selectivities).
1495 : *
1496 : * It however seems overly complex, and in a way we already do that
1497 : * because if we reject the whole clause as unsupported here, it will
1498 : * be eventually passed to clauselist_selectivity() which does exactly
1499 : * this (split into supported/unsupported clauses etc).
1500 : */
1501 42 : BoolExpr *expr = (BoolExpr *) clause;
1502 : ListCell *lc;
1503 :
1504 111 : foreach(lc, expr->args)
1505 : {
1506 : /*
1507 : * If we find an incompatible clause in the arguments, treat the
1508 : * whole clause as incompatible.
1509 : */
1510 69 : if (!statext_is_compatible_clause_internal(root,
1511 69 : (Node *) lfirst(lc),
1512 : relid, attnums, exprs,
1513 : leakproof))
1514 0 : return false;
1515 : }
1516 :
1517 42 : return true;
1518 : }
1519 :
1520 : /* Var/Expr IS NULL */
1521 75 : if (IsA(clause, NullTest))
1522 : {
1523 72 : NullTest *nt = (NullTest *) clause;
1524 :
1525 : /* Check Var IS NULL clauses by recursing. */
1526 72 : if (IsA(nt->arg, Var))
1527 45 : return statext_is_compatible_clause_internal(root,
1528 45 : (Node *) (nt->arg),
1529 : relid, attnums,
1530 : exprs, leakproof);
1531 :
1532 : /* Otherwise we have Expr IS NULL. */
1533 27 : *exprs = lappend(*exprs, nt->arg);
1534 27 : return true;
1535 : }
1536 :
1537 : /*
1538 : * Treat any other expressions as bare expressions to be matched against
1539 : * expressions in statistics objects.
1540 : */
1541 3 : *exprs = lappend(*exprs, clause);
1542 3 : return true;
1543 : }
1544 :
1545 : /*
1546 : * statext_is_compatible_clause
1547 : * Determines if the clause is compatible with MCV lists.
1548 : *
1549 : * See statext_is_compatible_clause_internal, above, for the basic rules.
1550 : * This layer deals with RestrictInfo superstructure and applies permissions
1551 : * checks to verify that it's okay to examine all mentioned Vars.
1552 : *
1553 : * Arguments:
1554 : * clause: clause to be inspected (in RestrictInfo form)
1555 : * relid: rel that all Vars in clause must belong to
1556 : * *attnums: input/output parameter collecting attribute numbers of all
1557 : * mentioned Vars. Note that we do not offset the attribute numbers,
1558 : * so we can't cope with system columns.
1559 : * *exprs: input/output parameter collecting primitive subclauses within
1560 : * the clause tree
1561 : *
1562 : * Returns false if there is something we definitively can't handle.
1563 : * On true return, we can proceed to match the *exprs against statistics.
1564 : */
1565 : static bool
1566 954 : statext_is_compatible_clause(PlannerInfo *root, Node *clause, Index relid,
1567 : Bitmapset **attnums, List **exprs)
1568 : {
1569 : RestrictInfo *rinfo;
1570 : int clause_relid;
1571 : bool leakproof;
1572 :
1573 : /*
1574 : * Special-case handling for bare BoolExpr AND clauses, because the
1575 : * restrictinfo machinery doesn't build RestrictInfos on top of AND
1576 : * clauses.
1577 : */
1578 954 : if (is_andclause(clause))
1579 : {
1580 24 : BoolExpr *expr = (BoolExpr *) clause;
1581 : ListCell *lc;
1582 :
1583 : /*
1584 : * Check that each sub-clause is compatible. We expect these to be
1585 : * RestrictInfos.
1586 : */
1587 81 : foreach(lc, expr->args)
1588 : {
1589 57 : if (!statext_is_compatible_clause(root, (Node *) lfirst(lc),
1590 : relid, attnums, exprs))
1591 0 : return false;
1592 : }
1593 :
1594 24 : return true;
1595 : }
1596 :
1597 : /* Otherwise it must be a RestrictInfo. */
1598 930 : if (!IsA(clause, RestrictInfo))
1599 0 : return false;
1600 930 : rinfo = (RestrictInfo *) clause;
1601 :
1602 : /* Pseudoconstants are not really interesting here. */
1603 930 : if (rinfo->pseudoconstant)
1604 3 : return false;
1605 :
1606 : /* Clauses referencing other varnos are incompatible. */
1607 927 : if (!bms_get_singleton_member(rinfo->clause_relids, &clause_relid) ||
1608 927 : clause_relid != relid)
1609 0 : return false;
1610 :
1611 : /*
1612 : * Check the clause, determine what attributes it references, and whether
1613 : * it includes any non-leakproof operators.
1614 : */
1615 927 : leakproof = true;
1616 927 : if (!statext_is_compatible_clause_internal(root, (Node *) rinfo->clause,
1617 : relid, attnums, exprs,
1618 : &leakproof))
1619 3 : return false;
1620 :
1621 : /*
1622 : * If the clause includes any non-leakproof operators, check that the user
1623 : * has permission to read all required attributes, otherwise the operators
1624 : * might reveal values from the MCV list that the user doesn't have
1625 : * permission to see. We require all rows to be selectable --- there must
1626 : * be no securityQuals from security barrier views or RLS policies. See
1627 : * similar code in examine_variable(), examine_simple_variable(), and
1628 : * statistic_proc_security_check().
1629 : *
1630 : * Note that for an inheritance child, the permission checks are performed
1631 : * on the inheritance root parent, and whole-table select privilege on the
1632 : * parent doesn't guarantee that the user could read all columns of the
1633 : * child. Therefore we must check all referenced columns.
1634 : */
1635 924 : if (!leakproof)
1636 : {
1637 126 : Bitmapset *clause_attnums = NULL;
1638 126 : int attnum = -1;
1639 :
1640 : /*
1641 : * We have to check per-column privileges. *attnums has the attnums
1642 : * for individual Vars we saw, but there may also be Vars within
1643 : * subexpressions in *exprs. We can use pull_varattnos() to extract
1644 : * those, but there's an impedance mismatch: attnums returned by
1645 : * pull_varattnos() are offset by FirstLowInvalidHeapAttributeNumber,
1646 : * while attnums within *attnums aren't. Convert *attnums to the
1647 : * offset style so we can combine the results.
1648 : */
1649 246 : while ((attnum = bms_next_member(*attnums, attnum)) >= 0)
1650 : {
1651 120 : clause_attnums =
1652 120 : bms_add_member(clause_attnums,
1653 : attnum - FirstLowInvalidHeapAttributeNumber);
1654 : }
1655 :
1656 : /* Now merge attnums from *exprs into clause_attnums */
1657 126 : if (*exprs != NIL)
1658 24 : pull_varattnos((Node *) *exprs, relid, &clause_attnums);
1659 :
1660 : /* Must have permission to read all rows from these columns */
1661 126 : if (!all_rows_selectable(root, relid, clause_attnums))
1662 114 : return false;
1663 : }
1664 :
1665 : /* If we reach here, the clause is OK */
1666 810 : return true;
1667 : }
1668 :
1669 : /*
1670 : * statext_mcv_clauselist_selectivity
1671 : * Estimate clauses using the best multi-column statistics.
1672 : *
1673 : * Applies available extended (multi-column) statistics on a table. There may
1674 : * be multiple applicable statistics (with respect to the clauses), in which
1675 : * case we use greedy approach. In each round we select the best statistic on
1676 : * a table (measured by the number of attributes extracted from the clauses
1677 : * and covered by it), and compute the selectivity for the supplied clauses.
1678 : * We repeat this process with the remaining clauses (if any), until none of
1679 : * the available statistics can be used.
1680 : *
1681 : * One of the main challenges with using MCV lists is how to extrapolate the
1682 : * estimate to the data not covered by the MCV list. To do that, we compute
1683 : * not only the "MCV selectivity" (selectivities for MCV items matching the
1684 : * supplied clauses), but also the following related selectivities:
1685 : *
1686 : * - simple selectivity: Computed without extended statistics, i.e. as if the
1687 : * columns/clauses were independent.
1688 : *
1689 : * - base selectivity: Similar to simple selectivity, but is computed using
1690 : * the extended statistic by adding up the base frequencies (that we compute
1691 : * and store for each MCV item) of matching MCV items.
1692 : *
1693 : * - total selectivity: Selectivity covered by the whole MCV list.
1694 : *
1695 : * These are passed to mcv_combine_selectivities() which combines them to
1696 : * produce a selectivity estimate that makes use of both per-column statistics
1697 : * and the multi-column MCV statistics.
1698 : *
1699 : * 'estimatedclauses' is an input/output parameter. We set bits for the
1700 : * 0-based 'clauses' indexes we estimate for and also skip clause items that
1701 : * already have a bit set.
1702 : */
1703 : static Selectivity
1704 1296 : statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
1705 : JoinType jointype, SpecialJoinInfo *sjinfo,
1706 : RelOptInfo *rel, Bitmapset **estimatedclauses,
1707 : bool is_or)
1708 : {
1709 : ListCell *l;
1710 : Bitmapset **list_attnums; /* attnums extracted from the clause */
1711 : List **list_exprs; /* expressions matched to any statistic */
1712 : int listidx;
1713 1296 : Selectivity sel = (is_or) ? 0.0 : 1.0;
1714 1296 : RangeTblEntry *rte = planner_rt_fetch(rel->relid, root);
1715 :
1716 : /* check if there's any stats that might be useful for us. */
1717 1296 : if (!has_stats_of_kind(rel->statlist, STATS_EXT_MCV))
1718 924 : return sel;
1719 :
1720 372 : list_attnums = palloc_array(Bitmapset *, list_length(clauses));
1721 :
1722 : /* expressions extracted from complex expressions */
1723 372 : list_exprs = palloc_array(List *, list_length(clauses));
1724 :
1725 : /*
1726 : * Pre-process the clauses list to extract the attnums and expressions
1727 : * seen in each item. We need to determine if there are any clauses which
1728 : * will be useful for selectivity estimations with extended stats. Along
1729 : * the way we'll record all of the attnums and expressions for each clause
1730 : * in lists which we'll reference later so we don't need to repeat the
1731 : * same work again.
1732 : *
1733 : * We also skip clauses that we already estimated using different types of
1734 : * statistics (we treat them as incompatible).
1735 : */
1736 372 : listidx = 0;
1737 1269 : foreach(l, clauses)
1738 : {
1739 897 : Node *clause = (Node *) lfirst(l);
1740 897 : Bitmapset *attnums = NULL;
1741 897 : List *exprs = NIL;
1742 :
1743 1794 : if (!bms_is_member(listidx, *estimatedclauses) &&
1744 897 : statext_is_compatible_clause(root, clause, rel->relid, &attnums, &exprs))
1745 : {
1746 777 : list_attnums[listidx] = attnums;
1747 777 : list_exprs[listidx] = exprs;
1748 : }
1749 : else
1750 : {
1751 120 : list_attnums[listidx] = NULL;
1752 120 : list_exprs[listidx] = NIL;
1753 : }
1754 :
1755 897 : listidx++;
1756 : }
1757 :
1758 : /* apply as many extended statistics as possible */
1759 : while (true)
1760 303 : {
1761 : StatisticExtInfo *stat;
1762 : List *stat_clauses;
1763 : Bitmapset *simple_clauses;
1764 :
1765 : /* find the best suited statistics object for these attnums */
1766 675 : stat = choose_best_statistics(rel->statlist, STATS_EXT_MCV, rte->inh,
1767 : list_attnums, list_exprs,
1768 : list_length(clauses));
1769 :
1770 : /*
1771 : * if no (additional) matching stats could be found then we've nothing
1772 : * to do
1773 : */
1774 675 : if (!stat)
1775 372 : break;
1776 :
1777 : /* Ensure choose_best_statistics produced an expected stats type. */
1778 : Assert(stat->kind == STATS_EXT_MCV);
1779 :
1780 : /* now filter the clauses to be estimated using the selected MCV */
1781 303 : stat_clauses = NIL;
1782 :
1783 : /* record which clauses are simple (single column or expression) */
1784 303 : simple_clauses = NULL;
1785 :
1786 303 : listidx = -1;
1787 1056 : foreach(l, clauses)
1788 : {
1789 : /* Increment the index before we decide if to skip the clause. */
1790 753 : listidx++;
1791 :
1792 : /*
1793 : * Ignore clauses from which we did not extract any attnums or
1794 : * expressions (this needs to be consistent with what we do in
1795 : * choose_best_statistics).
1796 : *
1797 : * This also eliminates already estimated clauses - both those
1798 : * estimated before and during applying extended statistics.
1799 : *
1800 : * XXX This check is needed because both bms_is_subset and
1801 : * stat_covers_expressions return true for empty attnums and
1802 : * expressions.
1803 : */
1804 753 : if (!list_attnums[listidx] && !list_exprs[listidx])
1805 18 : continue;
1806 :
1807 : /*
1808 : * The clause was not estimated yet, and we've extracted either
1809 : * attnums or expressions from it. Ignore it if it's not fully
1810 : * covered by the chosen statistics object.
1811 : *
1812 : * We need to check both attributes and expressions, and reject if
1813 : * either is not covered.
1814 : */
1815 735 : if (!bms_is_subset(list_attnums[listidx], stat->keys) ||
1816 705 : !stat_covers_expressions(stat, list_exprs[listidx], NULL))
1817 33 : continue;
1818 :
1819 : /*
1820 : * Now we know the clause is compatible (we have either attnums or
1821 : * expressions extracted from it), and was not estimated yet.
1822 : */
1823 :
1824 : /* record simple clauses (single column or expression) */
1825 825 : if ((list_attnums[listidx] == NULL &&
1826 123 : list_length(list_exprs[listidx]) == 1) ||
1827 1158 : (list_exprs[listidx] == NIL &&
1828 579 : bms_membership(list_attnums[listidx]) == BMS_SINGLETON))
1829 672 : simple_clauses = bms_add_member(simple_clauses,
1830 : list_length(stat_clauses));
1831 :
1832 : /* add clause to list and mark it as estimated */
1833 702 : stat_clauses = lappend(stat_clauses, (Node *) lfirst(l));
1834 702 : *estimatedclauses = bms_add_member(*estimatedclauses, listidx);
1835 :
1836 : /*
1837 : * Reset the pointers, so that choose_best_statistics knows this
1838 : * clause was estimated and does not consider it again.
1839 : */
1840 702 : bms_free(list_attnums[listidx]);
1841 702 : list_attnums[listidx] = NULL;
1842 :
1843 702 : list_free(list_exprs[listidx]);
1844 702 : list_exprs[listidx] = NULL;
1845 : }
1846 :
1847 303 : if (is_or)
1848 : {
1849 48 : bool *or_matches = NULL;
1850 48 : Selectivity simple_or_sel = 0.0,
1851 48 : stat_sel = 0.0;
1852 : MCVList *mcv_list;
1853 :
1854 : /* Load the MCV list stored in the statistics object */
1855 48 : mcv_list = statext_mcv_load(stat->statOid, rte->inh);
1856 :
1857 : /*
1858 : * Compute the selectivity of the ORed list of clauses covered by
1859 : * this statistics object by estimating each in turn and combining
1860 : * them using the formula P(A OR B) = P(A) + P(B) - P(A AND B).
1861 : * This allows us to use the multivariate MCV stats to better
1862 : * estimate the individual terms and their overlap.
1863 : *
1864 : * Each time we iterate this formula, the clause "A" above is
1865 : * equal to all the clauses processed so far, combined with "OR".
1866 : */
1867 48 : listidx = 0;
1868 168 : foreach(l, stat_clauses)
1869 : {
1870 120 : Node *clause = (Node *) lfirst(l);
1871 : Selectivity simple_sel,
1872 : overlap_simple_sel,
1873 : mcv_sel,
1874 : mcv_basesel,
1875 : overlap_mcvsel,
1876 : overlap_basesel,
1877 : mcv_totalsel,
1878 : clause_sel,
1879 : overlap_sel;
1880 :
1881 : /*
1882 : * "Simple" selectivity of the next clause and its overlap
1883 : * with any of the previous clauses. These are our initial
1884 : * estimates of P(B) and P(A AND B), assuming independence of
1885 : * columns/clauses.
1886 : */
1887 120 : simple_sel = clause_selectivity_ext(root, clause, varRelid,
1888 : jointype, sjinfo, false);
1889 :
1890 120 : overlap_simple_sel = simple_or_sel * simple_sel;
1891 :
1892 : /*
1893 : * New "simple" selectivity of all clauses seen so far,
1894 : * assuming independence.
1895 : */
1896 120 : simple_or_sel += simple_sel - overlap_simple_sel;
1897 120 : CLAMP_PROBABILITY(simple_or_sel);
1898 :
1899 : /*
1900 : * Multi-column estimate of this clause using MCV statistics,
1901 : * along with base and total selectivities, and corresponding
1902 : * selectivities for the overlap term P(A AND B).
1903 : */
1904 120 : mcv_sel = mcv_clause_selectivity_or(root, stat, mcv_list,
1905 : clause, &or_matches,
1906 : &mcv_basesel,
1907 : &overlap_mcvsel,
1908 : &overlap_basesel,
1909 : &mcv_totalsel);
1910 :
1911 : /*
1912 : * Combine the simple and multi-column estimates.
1913 : *
1914 : * If this clause is a simple single-column clause, then we
1915 : * just use the simple selectivity estimate for it, since the
1916 : * multi-column statistics are unlikely to improve on that
1917 : * (and in fact could make it worse). For the overlap, we
1918 : * always make use of the multi-column statistics.
1919 : */
1920 120 : if (bms_is_member(listidx, simple_clauses))
1921 96 : clause_sel = simple_sel;
1922 : else
1923 24 : clause_sel = mcv_combine_selectivities(simple_sel,
1924 : mcv_sel,
1925 : mcv_basesel,
1926 : mcv_totalsel);
1927 :
1928 120 : overlap_sel = mcv_combine_selectivities(overlap_simple_sel,
1929 : overlap_mcvsel,
1930 : overlap_basesel,
1931 : mcv_totalsel);
1932 :
1933 : /* Factor these into the result for this statistics object */
1934 120 : stat_sel += clause_sel - overlap_sel;
1935 120 : CLAMP_PROBABILITY(stat_sel);
1936 :
1937 120 : listidx++;
1938 : }
1939 :
1940 : /*
1941 : * Factor the result for this statistics object into the overall
1942 : * result. We treat the results from each separate statistics
1943 : * object as independent of one another.
1944 : */
1945 48 : sel = sel + stat_sel - sel * stat_sel;
1946 : }
1947 : else /* Implicitly-ANDed list of clauses */
1948 : {
1949 : Selectivity simple_sel,
1950 : mcv_sel,
1951 : mcv_basesel,
1952 : mcv_totalsel,
1953 : stat_sel;
1954 :
1955 : /*
1956 : * "Simple" selectivity, i.e. without any extended statistics,
1957 : * essentially assuming independence of the columns/clauses.
1958 : */
1959 255 : simple_sel = clauselist_selectivity_ext(root, stat_clauses,
1960 : varRelid, jointype,
1961 : sjinfo, false);
1962 :
1963 : /*
1964 : * Multi-column estimate using MCV statistics, along with base and
1965 : * total selectivities.
1966 : */
1967 255 : mcv_sel = mcv_clauselist_selectivity(root, stat, stat_clauses,
1968 : varRelid, jointype, sjinfo,
1969 : rel, &mcv_basesel,
1970 : &mcv_totalsel);
1971 :
1972 : /* Combine the simple and multi-column estimates. */
1973 255 : stat_sel = mcv_combine_selectivities(simple_sel,
1974 : mcv_sel,
1975 : mcv_basesel,
1976 : mcv_totalsel);
1977 :
1978 : /* Factor this into the overall result */
1979 255 : sel *= stat_sel;
1980 : }
1981 : }
1982 :
1983 372 : return sel;
1984 : }
1985 :
1986 : /*
1987 : * statext_clauselist_selectivity
1988 : * Estimate clauses using the best multi-column statistics.
1989 : */
1990 : Selectivity
1991 1296 : statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
1992 : JoinType jointype, SpecialJoinInfo *sjinfo,
1993 : RelOptInfo *rel, Bitmapset **estimatedclauses,
1994 : bool is_or)
1995 : {
1996 : Selectivity sel;
1997 :
1998 : /* First, try estimating clauses using a multivariate MCV list. */
1999 1296 : sel = statext_mcv_clauselist_selectivity(root, clauses, varRelid, jointype,
2000 : sjinfo, rel, estimatedclauses, is_or);
2001 :
2002 : /*
2003 : * Functional dependencies only work for clauses connected by AND, so for
2004 : * OR clauses we're done.
2005 : */
2006 1296 : if (is_or)
2007 78 : return sel;
2008 :
2009 : /*
2010 : * Then, apply functional dependencies on the remaining clauses by calling
2011 : * dependencies_clauselist_selectivity. Pass 'estimatedclauses' so the
2012 : * function can properly skip clauses already estimated above.
2013 : *
2014 : * The reasoning for applying dependencies last is that the more complex
2015 : * stats can track more complex correlations between the attributes, and
2016 : * so may be considered more reliable.
2017 : *
2018 : * For example, MCV list can give us an exact selectivity for values in
2019 : * two columns, while functional dependencies can only provide information
2020 : * about the overall strength of the dependency.
2021 : */
2022 1218 : sel *= dependencies_clauselist_selectivity(root, clauses, varRelid,
2023 : jointype, sjinfo, rel,
2024 : estimatedclauses);
2025 :
2026 1218 : return sel;
2027 : }
2028 :
2029 : /*
2030 : * examine_opclause_args
2031 : * Split an operator expression's arguments into Expr and Const parts.
2032 : *
2033 : * Attempts to match the arguments to either (Expr op Const) or (Const op
2034 : * Expr), possibly with a RelabelType on top. When the expression matches this
2035 : * form, returns true, otherwise returns false.
2036 : *
2037 : * Optionally returns pointers to the extracted Expr/Const nodes, when passed
2038 : * non-null pointers (exprp, cstp and expronleftp). The expronleftp flag
2039 : * specifies on which side of the operator we found the expression node.
2040 : */
2041 : bool
2042 1509 : examine_opclause_args(List *args, Node **exprp, Const **cstp,
2043 : bool *expronleftp)
2044 : {
2045 : Node *expr;
2046 : Const *cst;
2047 : bool expronleft;
2048 : Node *leftop,
2049 : *rightop;
2050 :
2051 : /* enforced by statext_is_compatible_clause_internal */
2052 : Assert(list_length(args) == 2);
2053 :
2054 1509 : leftop = linitial(args);
2055 1509 : rightop = lsecond(args);
2056 :
2057 : /* strip RelabelType from either side of the expression */
2058 1509 : if (IsA(leftop, RelabelType))
2059 162 : leftop = (Node *) ((RelabelType *) leftop)->arg;
2060 :
2061 1509 : if (IsA(rightop, RelabelType))
2062 30 : rightop = (Node *) ((RelabelType *) rightop)->arg;
2063 :
2064 1509 : if (IsA(rightop, Const))
2065 : {
2066 1428 : expr = leftop;
2067 1428 : cst = (Const *) rightop;
2068 1428 : expronleft = true;
2069 : }
2070 81 : else if (IsA(leftop, Const))
2071 : {
2072 81 : expr = rightop;
2073 81 : cst = (Const *) leftop;
2074 81 : expronleft = false;
2075 : }
2076 : else
2077 0 : return false;
2078 :
2079 : /* return pointers to the extracted parts if requested */
2080 1509 : if (exprp)
2081 1509 : *exprp = expr;
2082 :
2083 1509 : if (cstp)
2084 669 : *cstp = cst;
2085 :
2086 1509 : if (expronleftp)
2087 813 : *expronleftp = expronleft;
2088 :
2089 1509 : return true;
2090 : }
2091 :
2092 :
2093 : /*
2094 : * Compute statistics about expressions of a relation.
2095 : */
2096 : static void
2097 114 : compute_expr_stats(Relation onerel, AnlExprData *exprdata, int nexprs,
2098 : HeapTuple *rows, int numrows)
2099 : {
2100 : MemoryContext expr_context,
2101 : old_context;
2102 : int ind,
2103 : i;
2104 :
2105 114 : expr_context = AllocSetContextCreate(CurrentMemoryContext,
2106 : "Analyze Expression",
2107 : ALLOCSET_DEFAULT_SIZES);
2108 114 : old_context = MemoryContextSwitchTo(expr_context);
2109 :
2110 324 : for (ind = 0; ind < nexprs; ind++)
2111 : {
2112 210 : AnlExprData *thisdata = &exprdata[ind];
2113 210 : VacAttrStats *stats = thisdata->vacattrstat;
2114 210 : Node *expr = thisdata->expr;
2115 : TupleTableSlot *slot;
2116 : EState *estate;
2117 : ExprContext *econtext;
2118 : Datum *exprvals;
2119 : bool *exprnulls;
2120 : ExprState *exprstate;
2121 : int tcnt;
2122 :
2123 : /* Are we still in the main context? */
2124 : Assert(CurrentMemoryContext == expr_context);
2125 :
2126 : /*
2127 : * Need an EState for evaluation of expressions. Create it in the
2128 : * per-expression context to be sure it gets cleaned up at the bottom
2129 : * of the loop.
2130 : */
2131 210 : estate = CreateExecutorState();
2132 210 : econtext = GetPerTupleExprContext(estate);
2133 :
2134 : /* Set up expression evaluation state */
2135 210 : exprstate = ExecPrepareExpr((Expr *) expr, estate);
2136 :
2137 : /* Need a slot to hold the current heap tuple, too */
2138 210 : slot = MakeSingleTupleTableSlot(RelationGetDescr(onerel),
2139 : &TTSOpsHeapTuple);
2140 :
2141 : /* Arrange for econtext's scan tuple to be the tuple under test */
2142 210 : econtext->ecxt_scantuple = slot;
2143 :
2144 : /* Compute and save expression values */
2145 210 : exprvals = (Datum *) palloc(numrows * sizeof(Datum));
2146 210 : exprnulls = (bool *) palloc(numrows * sizeof(bool));
2147 :
2148 210 : tcnt = 0;
2149 230459 : for (i = 0; i < numrows; i++)
2150 : {
2151 : Datum datum;
2152 : bool isnull;
2153 :
2154 : /*
2155 : * Reset the per-tuple context each time, to reclaim any cruft
2156 : * left behind by evaluating the statistics expressions.
2157 : */
2158 230249 : ResetExprContext(econtext);
2159 :
2160 : /* Set up for expression evaluation */
2161 230249 : ExecStoreHeapTuple(rows[i], slot, false);
2162 :
2163 : /*
2164 : * Evaluate the expression. We do this in the per-tuple context so
2165 : * as not to leak memory, and then copy the result into the
2166 : * context created at the beginning of this function.
2167 : */
2168 230249 : datum = ExecEvalExprSwitchContext(exprstate,
2169 230249 : GetPerTupleExprContext(estate),
2170 : &isnull);
2171 230249 : if (isnull)
2172 : {
2173 6 : exprvals[tcnt] = (Datum) 0;
2174 6 : exprnulls[tcnt] = true;
2175 : }
2176 : else
2177 : {
2178 : /* Make sure we copy the data into the context. */
2179 : Assert(CurrentMemoryContext == expr_context);
2180 :
2181 460486 : exprvals[tcnt] = datumCopy(datum,
2182 230243 : stats->attrtype->typbyval,
2183 230243 : stats->attrtype->typlen);
2184 230243 : exprnulls[tcnt] = false;
2185 : }
2186 :
2187 230249 : tcnt++;
2188 : }
2189 :
2190 : /*
2191 : * Now we can compute the statistics for the expression columns.
2192 : *
2193 : * XXX Unlike compute_index_stats we don't need to switch and reset
2194 : * memory contexts here, because we're only computing stats for a
2195 : * single expression (and not iterating over many indexes), so we just
2196 : * do it in expr_context. Note that compute_stats copies the result
2197 : * into stats->anl_context, so it does not disappear.
2198 : */
2199 210 : if (tcnt > 0)
2200 : {
2201 : AttributeOpts *aopt =
2202 210 : get_attribute_options(onerel->rd_id, stats->tupattnum);
2203 :
2204 210 : stats->exprvals = exprvals;
2205 210 : stats->exprnulls = exprnulls;
2206 210 : stats->rowstride = 1;
2207 210 : stats->compute_stats(stats,
2208 : expr_fetch_func,
2209 : tcnt,
2210 : tcnt);
2211 :
2212 : /*
2213 : * If the n_distinct option is specified, it overrides the above
2214 : * computation.
2215 : */
2216 210 : if (aopt != NULL && aopt->n_distinct != 0.0)
2217 0 : stats->stadistinct = aopt->n_distinct;
2218 : }
2219 :
2220 : /* And clean up */
2221 210 : MemoryContextSwitchTo(expr_context);
2222 :
2223 210 : ExecDropSingleTupleTableSlot(slot);
2224 210 : FreeExecutorState(estate);
2225 210 : MemoryContextReset(expr_context);
2226 : }
2227 :
2228 114 : MemoryContextSwitchTo(old_context);
2229 114 : MemoryContextDelete(expr_context);
2230 114 : }
2231 :
2232 :
2233 : /*
2234 : * Fetch function for analyzing statistics object expressions.
2235 : *
2236 : * We have not bothered to construct tuples from the data, instead the data
2237 : * is just in Datum arrays.
2238 : */
2239 : static Datum
2240 230246 : expr_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull)
2241 : {
2242 : int i;
2243 :
2244 : /* exprvals and exprnulls are already offset for proper column */
2245 230246 : i = rownum * stats->rowstride;
2246 230246 : *isNull = stats->exprnulls[i];
2247 230246 : return stats->exprvals[i];
2248 : }
2249 :
2250 : /*
2251 : * Build analyze data for a list of expressions. As this is not tied
2252 : * directly to a relation (table or index), we have to fake some of
2253 : * the fields in examine_expression().
2254 : */
2255 : static AnlExprData *
2256 114 : build_expr_data(List *exprs, int stattarget)
2257 : {
2258 : int idx;
2259 114 : int nexprs = list_length(exprs);
2260 : AnlExprData *exprdata;
2261 : ListCell *lc;
2262 :
2263 114 : exprdata = (AnlExprData *) palloc0(nexprs * sizeof(AnlExprData));
2264 :
2265 114 : idx = 0;
2266 324 : foreach(lc, exprs)
2267 : {
2268 210 : Node *expr = (Node *) lfirst(lc);
2269 210 : AnlExprData *thisdata = &exprdata[idx];
2270 :
2271 210 : thisdata->expr = expr;
2272 210 : thisdata->vacattrstat = examine_expression(expr, stattarget);
2273 210 : idx++;
2274 : }
2275 :
2276 114 : return exprdata;
2277 : }
2278 :
2279 : /* form an array of pg_statistic rows (per update_attstats) */
2280 : static Datum
2281 114 : serialize_expr_stats(AnlExprData *exprdata, int nexprs)
2282 : {
2283 : int exprno;
2284 : Oid typOid;
2285 : Relation sd;
2286 :
2287 114 : ArrayBuildState *astate = NULL;
2288 :
2289 114 : sd = table_open(StatisticRelationId, RowExclusiveLock);
2290 :
2291 : /* lookup OID of composite type for pg_statistic */
2292 114 : typOid = get_rel_type_id(StatisticRelationId);
2293 114 : if (!OidIsValid(typOid))
2294 0 : ereport(ERROR,
2295 : (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2296 : errmsg("relation \"%s\" does not have a composite type",
2297 : "pg_statistic")));
2298 :
2299 324 : for (exprno = 0; exprno < nexprs; exprno++)
2300 : {
2301 : int i,
2302 : k;
2303 210 : VacAttrStats *stats = exprdata[exprno].vacattrstat;
2304 :
2305 : Datum values[Natts_pg_statistic];
2306 : bool nulls[Natts_pg_statistic];
2307 : HeapTuple stup;
2308 :
2309 210 : if (!stats->stats_valid)
2310 : {
2311 1 : astate = accumArrayResult(astate,
2312 : (Datum) 0,
2313 : true,
2314 : typOid,
2315 : CurrentMemoryContext);
2316 1 : continue;
2317 : }
2318 :
2319 : /*
2320 : * Construct a new pg_statistic tuple
2321 : */
2322 6688 : for (i = 0; i < Natts_pg_statistic; ++i)
2323 : {
2324 6479 : nulls[i] = false;
2325 : }
2326 :
2327 209 : values[Anum_pg_statistic_starelid - 1] = ObjectIdGetDatum(InvalidOid);
2328 209 : values[Anum_pg_statistic_staattnum - 1] = Int16GetDatum(InvalidAttrNumber);
2329 209 : values[Anum_pg_statistic_stainherit - 1] = BoolGetDatum(false);
2330 209 : values[Anum_pg_statistic_stanullfrac - 1] = Float4GetDatum(stats->stanullfrac);
2331 209 : values[Anum_pg_statistic_stawidth - 1] = Int32GetDatum(stats->stawidth);
2332 209 : values[Anum_pg_statistic_stadistinct - 1] = Float4GetDatum(stats->stadistinct);
2333 209 : i = Anum_pg_statistic_stakind1 - 1;
2334 1254 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2335 : {
2336 1045 : values[i++] = Int16GetDatum(stats->stakind[k]); /* stakindN */
2337 : }
2338 209 : i = Anum_pg_statistic_staop1 - 1;
2339 1254 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2340 : {
2341 1045 : values[i++] = ObjectIdGetDatum(stats->staop[k]); /* staopN */
2342 : }
2343 209 : i = Anum_pg_statistic_stacoll1 - 1;
2344 1254 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2345 : {
2346 1045 : values[i++] = ObjectIdGetDatum(stats->stacoll[k]); /* stacollN */
2347 : }
2348 209 : i = Anum_pg_statistic_stanumbers1 - 1;
2349 1254 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2350 : {
2351 1045 : int nnum = stats->numnumbers[k];
2352 :
2353 1045 : if (nnum > 0)
2354 : {
2355 : int n;
2356 373 : Datum *numdatums = (Datum *) palloc(nnum * sizeof(Datum));
2357 : ArrayType *arry;
2358 :
2359 2659 : for (n = 0; n < nnum; n++)
2360 2286 : numdatums[n] = Float4GetDatum(stats->stanumbers[k][n]);
2361 373 : arry = construct_array_builtin(numdatums, nnum, FLOAT4OID);
2362 373 : values[i++] = PointerGetDatum(arry); /* stanumbersN */
2363 : }
2364 : else
2365 : {
2366 672 : nulls[i] = true;
2367 672 : values[i++] = (Datum) 0;
2368 : }
2369 : }
2370 209 : i = Anum_pg_statistic_stavalues1 - 1;
2371 1254 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2372 : {
2373 1045 : if (stats->numvalues[k] > 0)
2374 : {
2375 : ArrayType *arry;
2376 :
2377 227 : arry = construct_array(stats->stavalues[k],
2378 : stats->numvalues[k],
2379 : stats->statypid[k],
2380 227 : stats->statyplen[k],
2381 227 : stats->statypbyval[k],
2382 227 : stats->statypalign[k]);
2383 227 : values[i++] = PointerGetDatum(arry); /* stavaluesN */
2384 : }
2385 : else
2386 : {
2387 818 : nulls[i] = true;
2388 818 : values[i++] = (Datum) 0;
2389 : }
2390 : }
2391 :
2392 209 : stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
2393 :
2394 209 : astate = accumArrayResult(astate,
2395 : heap_copy_tuple_as_datum(stup, RelationGetDescr(sd)),
2396 : false,
2397 : typOid,
2398 : CurrentMemoryContext);
2399 : }
2400 :
2401 114 : table_close(sd, RowExclusiveLock);
2402 :
2403 114 : return makeArrayResult(astate, CurrentMemoryContext);
2404 : }
2405 :
2406 : /*
2407 : * Loads pg_statistic record from expression statistics for expression
2408 : * identified by the supplied index.
2409 : *
2410 : * Returns the pg_statistic record found, or NULL if there is no statistics
2411 : * data to use.
2412 : */
2413 : HeapTuple
2414 826 : statext_expressions_load(Oid stxoid, bool inh, int idx)
2415 : {
2416 : bool isnull;
2417 : Datum value;
2418 : HeapTuple htup;
2419 : ExpandedArrayHeader *eah;
2420 : HeapTupleHeader td;
2421 : HeapTupleData tmptup;
2422 : HeapTuple tup;
2423 :
2424 826 : htup = SearchSysCache2(STATEXTDATASTXOID,
2425 : ObjectIdGetDatum(stxoid), BoolGetDatum(inh));
2426 826 : if (!HeapTupleIsValid(htup))
2427 0 : elog(ERROR, "cache lookup failed for statistics object %u", stxoid);
2428 :
2429 826 : value = SysCacheGetAttr(STATEXTDATASTXOID, htup,
2430 : Anum_pg_statistic_ext_data_stxdexpr, &isnull);
2431 826 : if (isnull)
2432 0 : elog(ERROR,
2433 : "requested statistics kind \"%c\" is not yet built for statistics object %u",
2434 : STATS_EXT_EXPRESSIONS, stxoid);
2435 :
2436 826 : eah = DatumGetExpandedArray(value);
2437 :
2438 826 : deconstruct_expanded_array(eah);
2439 :
2440 826 : if (eah->dnulls && eah->dnulls[idx])
2441 : {
2442 : /* No data found for this expression, give up. */
2443 1 : ReleaseSysCache(htup);
2444 1 : return NULL;
2445 : }
2446 :
2447 825 : td = DatumGetHeapTupleHeader(eah->dvalues[idx]);
2448 :
2449 : /* Build a temporary HeapTuple control structure */
2450 825 : tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
2451 825 : ItemPointerSetInvalid(&(tmptup.t_self));
2452 825 : tmptup.t_tableOid = InvalidOid;
2453 825 : tmptup.t_data = td;
2454 :
2455 825 : tup = heap_copytuple(&tmptup);
2456 :
2457 825 : ReleaseSysCache(htup);
2458 :
2459 825 : return tup;
2460 : }
2461 :
2462 : /*
2463 : * Evaluate the expressions, so that we can use the results to build
2464 : * all the requested statistics types. This matters especially for
2465 : * expensive expressions, of course.
2466 : */
2467 : static StatsBuildData *
2468 259 : make_build_data(Relation rel, StatExtEntry *stat, int numrows, HeapTuple *rows,
2469 : VacAttrStats **stats, int stattarget)
2470 : {
2471 : /* evaluated expressions */
2472 : StatsBuildData *result;
2473 : char *ptr;
2474 : Size len;
2475 :
2476 : int i;
2477 : int k;
2478 : int idx;
2479 : TupleTableSlot *slot;
2480 : EState *estate;
2481 : ExprContext *econtext;
2482 259 : List *exprstates = NIL;
2483 259 : int nkeys = bms_num_members(stat->columns) + list_length(stat->exprs);
2484 : ListCell *lc;
2485 :
2486 : /* allocate everything as a single chunk, so we can free it easily */
2487 259 : len = MAXALIGN(sizeof(StatsBuildData));
2488 259 : len += MAXALIGN(sizeof(AttrNumber) * nkeys); /* attnums */
2489 259 : len += MAXALIGN(sizeof(VacAttrStats *) * nkeys); /* stats */
2490 :
2491 : /* values */
2492 259 : len += MAXALIGN(sizeof(Datum *) * nkeys);
2493 259 : len += nkeys * MAXALIGN(sizeof(Datum) * numrows);
2494 :
2495 : /* nulls */
2496 259 : len += MAXALIGN(sizeof(bool *) * nkeys);
2497 259 : len += nkeys * MAXALIGN(sizeof(bool) * numrows);
2498 :
2499 259 : ptr = palloc(len);
2500 :
2501 : /* set the pointers */
2502 259 : result = (StatsBuildData *) ptr;
2503 259 : ptr += MAXALIGN(sizeof(StatsBuildData));
2504 :
2505 : /* attnums */
2506 259 : result->attnums = (AttrNumber *) ptr;
2507 259 : ptr += MAXALIGN(sizeof(AttrNumber) * nkeys);
2508 :
2509 : /* stats */
2510 259 : result->stats = (VacAttrStats **) ptr;
2511 259 : ptr += MAXALIGN(sizeof(VacAttrStats *) * nkeys);
2512 :
2513 : /* values */
2514 259 : result->values = (Datum **) ptr;
2515 259 : ptr += MAXALIGN(sizeof(Datum *) * nkeys);
2516 :
2517 : /* nulls */
2518 259 : result->nulls = (bool **) ptr;
2519 259 : ptr += MAXALIGN(sizeof(bool *) * nkeys);
2520 :
2521 894 : for (i = 0; i < nkeys; i++)
2522 : {
2523 635 : result->values[i] = (Datum *) ptr;
2524 635 : ptr += MAXALIGN(sizeof(Datum) * numrows);
2525 :
2526 635 : result->nulls[i] = (bool *) ptr;
2527 635 : ptr += MAXALIGN(sizeof(bool) * numrows);
2528 : }
2529 :
2530 : Assert((ptr - (char *) result) == len);
2531 :
2532 : /* we have it allocated, so let's fill the values */
2533 259 : result->nattnums = nkeys;
2534 259 : result->numrows = numrows;
2535 :
2536 : /* fill the attribute info - first attributes, then expressions */
2537 259 : idx = 0;
2538 259 : k = -1;
2539 684 : while ((k = bms_next_member(stat->columns, k)) >= 0)
2540 : {
2541 425 : result->attnums[idx] = k;
2542 425 : result->stats[idx] = stats[idx];
2543 :
2544 425 : idx++;
2545 : }
2546 :
2547 259 : k = -1;
2548 469 : foreach(lc, stat->exprs)
2549 : {
2550 210 : Node *expr = (Node *) lfirst(lc);
2551 :
2552 210 : result->attnums[idx] = k;
2553 210 : result->stats[idx] = examine_expression(expr, stattarget);
2554 :
2555 210 : idx++;
2556 210 : k--;
2557 : }
2558 :
2559 : /* first extract values for all the regular attributes */
2560 472096 : for (i = 0; i < numrows; i++)
2561 : {
2562 471837 : idx = 0;
2563 471837 : k = -1;
2564 1523407 : while ((k = bms_next_member(stat->columns, k)) >= 0)
2565 : {
2566 2103140 : result->values[idx][i] = heap_getattr(rows[i], k,
2567 1051570 : result->stats[idx]->tupDesc,
2568 1051570 : &result->nulls[idx][i]);
2569 :
2570 1051570 : idx++;
2571 : }
2572 : }
2573 :
2574 : /* Need an EState for evaluation expressions. */
2575 259 : estate = CreateExecutorState();
2576 259 : econtext = GetPerTupleExprContext(estate);
2577 :
2578 : /* Need a slot to hold the current heap tuple, too */
2579 259 : slot = MakeSingleTupleTableSlot(RelationGetDescr(rel),
2580 : &TTSOpsHeapTuple);
2581 :
2582 : /* Arrange for econtext's scan tuple to be the tuple under test */
2583 259 : econtext->ecxt_scantuple = slot;
2584 :
2585 : /* Set up expression evaluation state */
2586 259 : exprstates = ExecPrepareExprList(stat->exprs, estate);
2587 :
2588 472096 : for (i = 0; i < numrows; i++)
2589 : {
2590 : /*
2591 : * Reset the per-tuple context each time, to reclaim any cruft left
2592 : * behind by evaluating the statistics object expressions.
2593 : */
2594 471837 : ResetExprContext(econtext);
2595 :
2596 : /* Set up for expression evaluation */
2597 471837 : ExecStoreHeapTuple(rows[i], slot, false);
2598 :
2599 471837 : idx = bms_num_members(stat->columns);
2600 702086 : foreach(lc, exprstates)
2601 : {
2602 : Datum datum;
2603 : bool isnull;
2604 230249 : ExprState *exprstate = (ExprState *) lfirst(lc);
2605 :
2606 : /*
2607 : * XXX This probably leaks memory. Maybe we should use
2608 : * ExecEvalExprSwitchContext but then we need to copy the result
2609 : * somewhere else.
2610 : */
2611 230249 : datum = ExecEvalExpr(exprstate,
2612 230249 : GetPerTupleExprContext(estate),
2613 : &isnull);
2614 230249 : if (isnull)
2615 : {
2616 6 : result->values[idx][i] = (Datum) 0;
2617 6 : result->nulls[idx][i] = true;
2618 : }
2619 : else
2620 : {
2621 230243 : result->values[idx][i] = datum;
2622 230243 : result->nulls[idx][i] = false;
2623 : }
2624 :
2625 230249 : idx++;
2626 : }
2627 : }
2628 :
2629 259 : ExecDropSingleTupleTableSlot(slot);
2630 259 : FreeExecutorState(estate);
2631 :
2632 259 : return result;
2633 : }
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