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) 1996-2024, 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(Relation rel, 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, double totalrows,
93 : AnlExprData *exprdata, int nexprs,
94 : HeapTuple *rows, int numrows);
95 : static Datum serialize_expr_stats(AnlExprData *exprdata, int nexprs);
96 : static Datum expr_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
97 : static AnlExprData *build_expr_data(List *exprs, int stattarget);
98 :
99 : static StatsBuildData *make_build_data(Relation rel, StatExtEntry *stat,
100 : int numrows, HeapTuple *rows,
101 : VacAttrStats **stats, int stattarget);
102 :
103 :
104 : /*
105 : * Compute requested extended stats, using the rows sampled for the plain
106 : * (single-column) stats.
107 : *
108 : * This fetches a list of stats types from pg_statistic_ext, computes the
109 : * requested stats, and serializes them back into the catalog.
110 : */
111 : void
112 8352 : BuildRelationExtStatistics(Relation onerel, bool inh, double totalrows,
113 : int numrows, HeapTuple *rows,
114 : int natts, VacAttrStats **vacattrstats)
115 : {
116 : Relation pg_stext;
117 : ListCell *lc;
118 : List *statslist;
119 : MemoryContext cxt;
120 : MemoryContext oldcxt;
121 : int64 ext_cnt;
122 :
123 : /* Do nothing if there are no columns to analyze. */
124 8352 : if (!natts)
125 6 : return;
126 :
127 : /* the list of stats has to be allocated outside the memory context */
128 8346 : pg_stext = table_open(StatisticExtRelationId, RowExclusiveLock);
129 8346 : statslist = fetch_statentries_for_relation(pg_stext, RelationGetRelid(onerel));
130 :
131 : /* memory context for building each statistics object */
132 8346 : cxt = AllocSetContextCreate(CurrentMemoryContext,
133 : "BuildRelationExtStatistics",
134 : ALLOCSET_DEFAULT_SIZES);
135 8346 : oldcxt = MemoryContextSwitchTo(cxt);
136 :
137 : /* report this phase */
138 8346 : if (statslist != NIL)
139 : {
140 270 : const int index[] = {
141 : PROGRESS_ANALYZE_PHASE,
142 : PROGRESS_ANALYZE_EXT_STATS_TOTAL
143 : };
144 540 : const int64 val[] = {
145 : PROGRESS_ANALYZE_PHASE_COMPUTE_EXT_STATS,
146 270 : list_length(statslist)
147 : };
148 :
149 270 : pgstat_progress_update_multi_param(2, index, val);
150 : }
151 :
152 8346 : ext_cnt = 0;
153 8712 : foreach(lc, statslist)
154 : {
155 366 : StatExtEntry *stat = (StatExtEntry *) lfirst(lc);
156 366 : MVNDistinct *ndistinct = NULL;
157 366 : MVDependencies *dependencies = NULL;
158 366 : MCVList *mcv = NULL;
159 366 : Datum exprstats = (Datum) 0;
160 : VacAttrStats **stats;
161 : ListCell *lc2;
162 : int stattarget;
163 : StatsBuildData *data;
164 :
165 : /*
166 : * Check if we can build these stats based on the column analyzed. If
167 : * not, report this fact (except in autovacuum) and move on.
168 : */
169 366 : stats = lookup_var_attr_stats(onerel, stat->columns, stat->exprs,
170 : natts, vacattrstats);
171 366 : if (!stats)
172 : {
173 12 : if (!AmAutoVacuumWorkerProcess())
174 12 : ereport(WARNING,
175 : (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
176 : errmsg("statistics object \"%s.%s\" could not be computed for relation \"%s.%s\"",
177 : stat->schema, stat->name,
178 : get_namespace_name(onerel->rd_rel->relnamespace),
179 : RelationGetRelationName(onerel)),
180 : errtable(onerel)));
181 12 : continue;
182 : }
183 :
184 : /* compute statistics target for this statistics object */
185 354 : stattarget = statext_compute_stattarget(stat->stattarget,
186 354 : bms_num_members(stat->columns),
187 : stats);
188 :
189 : /*
190 : * Don't rebuild statistics objects with statistics target set to 0
191 : * (we just leave the existing values around, just like we do for
192 : * regular per-column statistics).
193 : */
194 354 : if (stattarget == 0)
195 6 : continue;
196 :
197 : /* evaluate expressions (if the statistics object has any) */
198 348 : data = make_build_data(onerel, stat, numrows, rows, stats, stattarget);
199 :
200 : /* compute statistic of each requested type */
201 954 : foreach(lc2, stat->types)
202 : {
203 606 : char t = (char) lfirst_int(lc2);
204 :
205 606 : if (t == STATS_EXT_NDISTINCT)
206 156 : ndistinct = statext_ndistinct_build(totalrows, data);
207 450 : else if (t == STATS_EXT_DEPENDENCIES)
208 120 : dependencies = statext_dependencies_build(data);
209 330 : else if (t == STATS_EXT_MCV)
210 180 : mcv = statext_mcv_build(data, totalrows, stattarget);
211 150 : else if (t == STATS_EXT_EXPRESSIONS)
212 : {
213 : AnlExprData *exprdata;
214 : int nexprs;
215 :
216 : /* should not happen, thanks to checks when defining stats */
217 150 : if (!stat->exprs)
218 0 : elog(ERROR, "requested expression stats, but there are no expressions");
219 :
220 150 : exprdata = build_expr_data(stat->exprs, stattarget);
221 150 : nexprs = list_length(stat->exprs);
222 :
223 150 : compute_expr_stats(onerel, totalrows,
224 : exprdata, nexprs,
225 : rows, numrows);
226 :
227 150 : exprstats = serialize_expr_stats(exprdata, nexprs);
228 : }
229 : }
230 :
231 : /* store the statistics in the catalog */
232 348 : statext_store(stat->statOid, inh,
233 : ndistinct, dependencies, mcv, exprstats, stats);
234 :
235 : /* for reporting progress */
236 348 : pgstat_progress_update_param(PROGRESS_ANALYZE_EXT_STATS_COMPUTED,
237 : ++ext_cnt);
238 :
239 : /* free the data used for building this statistics object */
240 348 : MemoryContextReset(cxt);
241 : }
242 :
243 8346 : MemoryContextSwitchTo(oldcxt);
244 8346 : MemoryContextDelete(cxt);
245 :
246 8346 : list_free(statslist);
247 :
248 8346 : table_close(pg_stext, RowExclusiveLock);
249 : }
250 :
251 : /*
252 : * ComputeExtStatisticsRows
253 : * Compute number of rows required by extended statistics on a table.
254 : *
255 : * Computes number of rows we need to sample to build extended statistics on a
256 : * table. This only looks at statistics we can actually build - for example
257 : * when analyzing only some of the columns, this will skip statistics objects
258 : * that would require additional columns.
259 : *
260 : * See statext_compute_stattarget for details about how we compute the
261 : * statistics target for a statistics object (from the object target,
262 : * attribute targets and default statistics target).
263 : */
264 : int
265 12302 : ComputeExtStatisticsRows(Relation onerel,
266 : int natts, VacAttrStats **vacattrstats)
267 : {
268 : Relation pg_stext;
269 : ListCell *lc;
270 : List *lstats;
271 : MemoryContext cxt;
272 : MemoryContext oldcxt;
273 12302 : int result = 0;
274 :
275 : /* If there are no columns to analyze, just return 0. */
276 12302 : if (!natts)
277 6 : return 0;
278 :
279 12296 : cxt = AllocSetContextCreate(CurrentMemoryContext,
280 : "ComputeExtStatisticsRows",
281 : ALLOCSET_DEFAULT_SIZES);
282 12296 : oldcxt = MemoryContextSwitchTo(cxt);
283 :
284 12296 : pg_stext = table_open(StatisticExtRelationId, RowExclusiveLock);
285 12296 : lstats = fetch_statentries_for_relation(pg_stext, RelationGetRelid(onerel));
286 :
287 12662 : foreach(lc, lstats)
288 : {
289 366 : StatExtEntry *stat = (StatExtEntry *) lfirst(lc);
290 : int stattarget;
291 : VacAttrStats **stats;
292 366 : int nattrs = bms_num_members(stat->columns);
293 :
294 : /*
295 : * Check if we can build this statistics object based on the columns
296 : * analyzed. If not, ignore it (don't report anything, we'll do that
297 : * during the actual build BuildRelationExtStatistics).
298 : */
299 366 : stats = lookup_var_attr_stats(onerel, stat->columns, stat->exprs,
300 : natts, vacattrstats);
301 :
302 366 : if (!stats)
303 12 : continue;
304 :
305 : /*
306 : * Compute statistics target, based on what's set for the statistic
307 : * object itself, and for its attributes.
308 : */
309 354 : stattarget = statext_compute_stattarget(stat->stattarget,
310 : nattrs, stats);
311 :
312 : /* Use the largest value for all statistics objects. */
313 354 : if (stattarget > result)
314 252 : result = stattarget;
315 : }
316 :
317 12296 : table_close(pg_stext, RowExclusiveLock);
318 :
319 12296 : MemoryContextSwitchTo(oldcxt);
320 12296 : MemoryContextDelete(cxt);
321 :
322 : /* compute sample size based on the statistics target */
323 12296 : return (300 * result);
324 : }
325 :
326 : /*
327 : * statext_compute_stattarget
328 : * compute statistics target for an extended statistic
329 : *
330 : * When computing target for extended statistics objects, we consider three
331 : * places where the target may be set - the statistics object itself,
332 : * attributes the statistics object is defined on, and then the default
333 : * statistics target.
334 : *
335 : * First we look at what's set for the statistics object itself, using the
336 : * ALTER STATISTICS ... SET STATISTICS command. If we find a valid value
337 : * there (i.e. not -1) we're done. Otherwise we look at targets set for any
338 : * of the attributes the statistic is defined on, and if there are columns
339 : * with defined target, we use the maximum value. We do this mostly for
340 : * backwards compatibility, because this is what we did before having
341 : * statistics target for extended statistics.
342 : *
343 : * And finally, if we still don't have a statistics target, we use the value
344 : * set in default_statistics_target.
345 : */
346 : static int
347 708 : statext_compute_stattarget(int stattarget, int nattrs, VacAttrStats **stats)
348 : {
349 : int i;
350 :
351 : /*
352 : * If there's statistics target set for the statistics object, use it. It
353 : * may be set to 0 which disables building of that statistic.
354 : */
355 708 : if (stattarget >= 0)
356 12 : return stattarget;
357 :
358 : /*
359 : * The target for the statistics object is set to -1, in which case we
360 : * look at the maximum target set for any of the attributes the object is
361 : * defined on.
362 : */
363 1920 : for (i = 0; i < nattrs; i++)
364 : {
365 : /* keep the maximum statistics target */
366 1224 : if (stats[i]->attstattarget > stattarget)
367 528 : stattarget = stats[i]->attstattarget;
368 : }
369 :
370 : /*
371 : * If the value is still negative (so neither the statistics object nor
372 : * any of the columns have custom statistics target set), use the global
373 : * default target.
374 : */
375 696 : if (stattarget < 0)
376 168 : stattarget = default_statistics_target;
377 :
378 : /* As this point we should have a valid statistics target. */
379 : Assert((stattarget >= 0) && (stattarget <= MAX_STATISTICS_TARGET));
380 :
381 696 : return stattarget;
382 : }
383 :
384 : /*
385 : * statext_is_kind_built
386 : * Is this stat kind built in the given pg_statistic_ext_data tuple?
387 : */
388 : bool
389 7344 : statext_is_kind_built(HeapTuple htup, char type)
390 : {
391 : AttrNumber attnum;
392 :
393 7344 : switch (type)
394 : {
395 1836 : case STATS_EXT_NDISTINCT:
396 1836 : attnum = Anum_pg_statistic_ext_data_stxdndistinct;
397 1836 : break;
398 :
399 1836 : case STATS_EXT_DEPENDENCIES:
400 1836 : attnum = Anum_pg_statistic_ext_data_stxddependencies;
401 1836 : break;
402 :
403 1836 : case STATS_EXT_MCV:
404 1836 : attnum = Anum_pg_statistic_ext_data_stxdmcv;
405 1836 : break;
406 :
407 1836 : case STATS_EXT_EXPRESSIONS:
408 1836 : attnum = Anum_pg_statistic_ext_data_stxdexpr;
409 1836 : break;
410 :
411 0 : default:
412 0 : elog(ERROR, "unexpected statistics type requested: %d", type);
413 : }
414 :
415 7344 : return !heap_attisnull(htup, attnum, NULL);
416 : }
417 :
418 : /*
419 : * Return a list (of StatExtEntry) of statistics objects for the given relation.
420 : */
421 : static List *
422 20642 : fetch_statentries_for_relation(Relation pg_statext, Oid relid)
423 : {
424 : SysScanDesc scan;
425 : ScanKeyData skey;
426 : HeapTuple htup;
427 20642 : List *result = NIL;
428 :
429 : /*
430 : * Prepare to scan pg_statistic_ext for entries having stxrelid = this
431 : * rel.
432 : */
433 20642 : ScanKeyInit(&skey,
434 : Anum_pg_statistic_ext_stxrelid,
435 : BTEqualStrategyNumber, F_OIDEQ,
436 : ObjectIdGetDatum(relid));
437 :
438 20642 : scan = systable_beginscan(pg_statext, StatisticExtRelidIndexId, true,
439 : NULL, 1, &skey);
440 :
441 21374 : while (HeapTupleIsValid(htup = systable_getnext(scan)))
442 : {
443 : StatExtEntry *entry;
444 : Datum datum;
445 : bool isnull;
446 : int i;
447 : ArrayType *arr;
448 : char *enabled;
449 : Form_pg_statistic_ext staForm;
450 732 : List *exprs = NIL;
451 :
452 732 : entry = palloc0(sizeof(StatExtEntry));
453 732 : staForm = (Form_pg_statistic_ext) GETSTRUCT(htup);
454 732 : entry->statOid = staForm->oid;
455 732 : entry->schema = get_namespace_name(staForm->stxnamespace);
456 732 : entry->name = pstrdup(NameStr(staForm->stxname));
457 2028 : for (i = 0; i < staForm->stxkeys.dim1; i++)
458 : {
459 1296 : entry->columns = bms_add_member(entry->columns,
460 1296 : staForm->stxkeys.values[i]);
461 : }
462 :
463 732 : datum = SysCacheGetAttr(STATEXTOID, htup, Anum_pg_statistic_ext_stxstattarget, &isnull);
464 732 : entry->stattarget = isnull ? -1 : DatumGetInt16(datum);
465 :
466 : /* decode the stxkind char array into a list of chars */
467 732 : datum = SysCacheGetAttrNotNull(STATEXTOID, htup,
468 : Anum_pg_statistic_ext_stxkind);
469 732 : arr = DatumGetArrayTypeP(datum);
470 732 : if (ARR_NDIM(arr) != 1 ||
471 732 : ARR_HASNULL(arr) ||
472 732 : ARR_ELEMTYPE(arr) != CHAROID)
473 0 : elog(ERROR, "stxkind is not a 1-D char array");
474 732 : enabled = (char *) ARR_DATA_PTR(arr);
475 2052 : for (i = 0; i < ARR_DIMS(arr)[0]; i++)
476 : {
477 : Assert((enabled[i] == STATS_EXT_NDISTINCT) ||
478 : (enabled[i] == STATS_EXT_DEPENDENCIES) ||
479 : (enabled[i] == STATS_EXT_MCV) ||
480 : (enabled[i] == STATS_EXT_EXPRESSIONS));
481 1320 : entry->types = lappend_int(entry->types, (int) enabled[i]);
482 : }
483 :
484 : /* decode expression (if any) */
485 732 : datum = SysCacheGetAttr(STATEXTOID, htup,
486 : Anum_pg_statistic_ext_stxexprs, &isnull);
487 :
488 732 : if (!isnull)
489 : {
490 : char *exprsString;
491 :
492 300 : exprsString = TextDatumGetCString(datum);
493 300 : exprs = (List *) stringToNode(exprsString);
494 :
495 300 : pfree(exprsString);
496 :
497 : /*
498 : * Run the expressions through eval_const_expressions. This is not
499 : * just an optimization, but is necessary, because the planner
500 : * will be comparing them to similarly-processed qual clauses, and
501 : * may fail to detect valid matches without this. We must not use
502 : * canonicalize_qual, however, since these aren't qual
503 : * expressions.
504 : */
505 300 : exprs = (List *) eval_const_expressions(NULL, (Node *) exprs);
506 :
507 : /* May as well fix opfuncids too */
508 300 : fix_opfuncids((Node *) exprs);
509 : }
510 :
511 732 : entry->exprs = exprs;
512 :
513 732 : result = lappend(result, entry);
514 : }
515 :
516 20642 : systable_endscan(scan);
517 :
518 20642 : return result;
519 : }
520 :
521 : /*
522 : * examine_attribute -- pre-analysis of a single column
523 : *
524 : * Determine whether the column is analyzable; if so, create and initialize
525 : * a VacAttrStats struct for it. If not, return NULL.
526 : */
527 : static VacAttrStats *
528 576 : examine_attribute(Node *expr)
529 : {
530 : HeapTuple typtuple;
531 : VacAttrStats *stats;
532 : int i;
533 : bool ok;
534 :
535 : /*
536 : * Create the VacAttrStats struct.
537 : */
538 576 : stats = (VacAttrStats *) palloc0(sizeof(VacAttrStats));
539 576 : stats->attstattarget = -1;
540 :
541 : /*
542 : * When analyzing an expression, believe the expression tree's type not
543 : * the column datatype --- the latter might be the opckeytype storage type
544 : * of the opclass, which is not interesting for our purposes. (Note: if
545 : * we did anything with non-expression statistics columns, we'd need to
546 : * figure out where to get the correct type info from, but for now that's
547 : * not a problem.) It's not clear whether anyone will care about the
548 : * typmod, but we store that too just in case.
549 : */
550 576 : stats->attrtypid = exprType(expr);
551 576 : stats->attrtypmod = exprTypmod(expr);
552 576 : stats->attrcollid = exprCollation(expr);
553 :
554 576 : typtuple = SearchSysCacheCopy1(TYPEOID,
555 : ObjectIdGetDatum(stats->attrtypid));
556 576 : if (!HeapTupleIsValid(typtuple))
557 0 : elog(ERROR, "cache lookup failed for type %u", stats->attrtypid);
558 576 : stats->attrtype = (Form_pg_type) GETSTRUCT(typtuple);
559 :
560 : /*
561 : * We don't actually analyze individual attributes, so no need to set the
562 : * memory context.
563 : */
564 576 : stats->anl_context = NULL;
565 576 : stats->tupattnum = InvalidAttrNumber;
566 :
567 : /*
568 : * The fields describing the stats->stavalues[n] element types default to
569 : * the type of the data being analyzed, but the type-specific typanalyze
570 : * function can change them if it wants to store something else.
571 : */
572 3456 : for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
573 : {
574 2880 : stats->statypid[i] = stats->attrtypid;
575 2880 : stats->statyplen[i] = stats->attrtype->typlen;
576 2880 : stats->statypbyval[i] = stats->attrtype->typbyval;
577 2880 : stats->statypalign[i] = stats->attrtype->typalign;
578 : }
579 :
580 : /*
581 : * Call the type-specific typanalyze function. If none is specified, use
582 : * std_typanalyze().
583 : */
584 576 : if (OidIsValid(stats->attrtype->typanalyze))
585 0 : ok = DatumGetBool(OidFunctionCall1(stats->attrtype->typanalyze,
586 : PointerGetDatum(stats)));
587 : else
588 576 : ok = std_typanalyze(stats);
589 :
590 576 : if (!ok || stats->compute_stats == NULL || stats->minrows <= 0)
591 : {
592 0 : heap_freetuple(typtuple);
593 0 : pfree(stats);
594 0 : return NULL;
595 : }
596 :
597 576 : return stats;
598 : }
599 :
600 : /*
601 : * examine_expression -- pre-analysis of a single expression
602 : *
603 : * Determine whether the expression is analyzable; if so, create and initialize
604 : * a VacAttrStats struct for it. If not, return NULL.
605 : */
606 : static VacAttrStats *
607 576 : examine_expression(Node *expr, int stattarget)
608 : {
609 : HeapTuple typtuple;
610 : VacAttrStats *stats;
611 : int i;
612 : bool ok;
613 :
614 : Assert(expr != NULL);
615 :
616 : /*
617 : * Create the VacAttrStats struct.
618 : */
619 576 : stats = (VacAttrStats *) palloc0(sizeof(VacAttrStats));
620 :
621 : /*
622 : * We can't have statistics target specified for the expression, so we
623 : * could use either the default_statistics_target, or the target computed
624 : * for the extended statistics. The second option seems more reasonable.
625 : */
626 576 : stats->attstattarget = stattarget;
627 :
628 : /*
629 : * When analyzing an expression, believe the expression tree's type.
630 : */
631 576 : stats->attrtypid = exprType(expr);
632 576 : stats->attrtypmod = exprTypmod(expr);
633 :
634 : /*
635 : * We don't allow collation to be specified in CREATE STATISTICS, so we
636 : * have to use the collation specified for the expression. It's possible
637 : * to specify the collation in the expression "(col COLLATE "en_US")" in
638 : * which case exprCollation() does the right thing.
639 : */
640 576 : stats->attrcollid = exprCollation(expr);
641 :
642 576 : typtuple = SearchSysCacheCopy1(TYPEOID,
643 : ObjectIdGetDatum(stats->attrtypid));
644 576 : if (!HeapTupleIsValid(typtuple))
645 0 : elog(ERROR, "cache lookup failed for type %u", stats->attrtypid);
646 :
647 576 : stats->attrtype = (Form_pg_type) GETSTRUCT(typtuple);
648 576 : stats->anl_context = CurrentMemoryContext; /* XXX should be using
649 : * something else? */
650 576 : stats->tupattnum = InvalidAttrNumber;
651 :
652 : /*
653 : * The fields describing the stats->stavalues[n] element types default to
654 : * the type of the data being analyzed, but the type-specific typanalyze
655 : * function can change them if it wants to store something else.
656 : */
657 3456 : for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
658 : {
659 2880 : stats->statypid[i] = stats->attrtypid;
660 2880 : stats->statyplen[i] = stats->attrtype->typlen;
661 2880 : stats->statypbyval[i] = stats->attrtype->typbyval;
662 2880 : stats->statypalign[i] = stats->attrtype->typalign;
663 : }
664 :
665 : /*
666 : * Call the type-specific typanalyze function. If none is specified, use
667 : * std_typanalyze().
668 : */
669 576 : if (OidIsValid(stats->attrtype->typanalyze))
670 0 : ok = DatumGetBool(OidFunctionCall1(stats->attrtype->typanalyze,
671 : PointerGetDatum(stats)));
672 : else
673 576 : ok = std_typanalyze(stats);
674 :
675 576 : if (!ok || stats->compute_stats == NULL || stats->minrows <= 0)
676 : {
677 0 : heap_freetuple(typtuple);
678 0 : pfree(stats);
679 0 : return NULL;
680 : }
681 :
682 576 : return stats;
683 : }
684 :
685 : /*
686 : * Using 'vacatts' of size 'nvacatts' as input data, return a newly-built
687 : * VacAttrStats array which includes only the items corresponding to
688 : * attributes indicated by 'attrs'. If we don't have all of the per-column
689 : * stats available to compute the extended stats, then we return NULL to
690 : * indicate to the caller that the stats should not be built.
691 : */
692 : static VacAttrStats **
693 732 : lookup_var_attr_stats(Relation rel, Bitmapset *attrs, List *exprs,
694 : int nvacatts, VacAttrStats **vacatts)
695 : {
696 732 : int i = 0;
697 732 : int x = -1;
698 : int natts;
699 : VacAttrStats **stats;
700 : ListCell *lc;
701 :
702 732 : natts = bms_num_members(attrs) + list_length(exprs);
703 :
704 732 : stats = (VacAttrStats **) palloc(natts * sizeof(VacAttrStats *));
705 :
706 : /* lookup VacAttrStats info for the requested columns (same attnum) */
707 1992 : while ((x = bms_next_member(attrs, x)) >= 0)
708 : {
709 : int j;
710 :
711 1284 : stats[i] = NULL;
712 4080 : for (j = 0; j < nvacatts; j++)
713 : {
714 4056 : if (x == vacatts[j]->tupattnum)
715 : {
716 1260 : stats[i] = vacatts[j];
717 1260 : break;
718 : }
719 : }
720 :
721 1284 : if (!stats[i])
722 : {
723 : /*
724 : * Looks like stats were not gathered for one of the columns
725 : * required. We'll be unable to build the extended stats without
726 : * this column.
727 : */
728 24 : pfree(stats);
729 24 : return NULL;
730 : }
731 :
732 1260 : i++;
733 : }
734 :
735 : /* also add info for expressions */
736 1284 : foreach(lc, exprs)
737 : {
738 576 : Node *expr = (Node *) lfirst(lc);
739 :
740 576 : stats[i] = examine_attribute(expr);
741 :
742 : /*
743 : * XXX We need tuple descriptor later, and we just grab it from
744 : * stats[0]->tupDesc (see e.g. statext_mcv_build). But as coded
745 : * examine_attribute does not set that, so just grab it from the first
746 : * vacatts element.
747 : */
748 576 : stats[i]->tupDesc = vacatts[0]->tupDesc;
749 :
750 576 : i++;
751 : }
752 :
753 708 : return stats;
754 : }
755 :
756 : /*
757 : * statext_store
758 : * Serializes the statistics and stores them into the pg_statistic_ext_data
759 : * tuple.
760 : */
761 : static void
762 348 : statext_store(Oid statOid, bool inh,
763 : MVNDistinct *ndistinct, MVDependencies *dependencies,
764 : MCVList *mcv, Datum exprs, VacAttrStats **stats)
765 : {
766 : Relation pg_stextdata;
767 : HeapTuple stup;
768 : Datum values[Natts_pg_statistic_ext_data];
769 : bool nulls[Natts_pg_statistic_ext_data];
770 :
771 348 : pg_stextdata = table_open(StatisticExtDataRelationId, RowExclusiveLock);
772 :
773 348 : memset(nulls, true, sizeof(nulls));
774 348 : memset(values, 0, sizeof(values));
775 :
776 : /* basic info */
777 348 : values[Anum_pg_statistic_ext_data_stxoid - 1] = ObjectIdGetDatum(statOid);
778 348 : nulls[Anum_pg_statistic_ext_data_stxoid - 1] = false;
779 :
780 348 : values[Anum_pg_statistic_ext_data_stxdinherit - 1] = BoolGetDatum(inh);
781 348 : nulls[Anum_pg_statistic_ext_data_stxdinherit - 1] = false;
782 :
783 : /*
784 : * Construct a new pg_statistic_ext_data tuple, replacing the calculated
785 : * stats.
786 : */
787 348 : if (ndistinct != NULL)
788 : {
789 156 : bytea *data = statext_ndistinct_serialize(ndistinct);
790 :
791 156 : nulls[Anum_pg_statistic_ext_data_stxdndistinct - 1] = (data == NULL);
792 156 : values[Anum_pg_statistic_ext_data_stxdndistinct - 1] = PointerGetDatum(data);
793 : }
794 :
795 348 : if (dependencies != NULL)
796 : {
797 102 : bytea *data = statext_dependencies_serialize(dependencies);
798 :
799 102 : nulls[Anum_pg_statistic_ext_data_stxddependencies - 1] = (data == NULL);
800 102 : values[Anum_pg_statistic_ext_data_stxddependencies - 1] = PointerGetDatum(data);
801 : }
802 348 : if (mcv != NULL)
803 : {
804 180 : bytea *data = statext_mcv_serialize(mcv, stats);
805 :
806 180 : nulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = (data == NULL);
807 180 : values[Anum_pg_statistic_ext_data_stxdmcv - 1] = PointerGetDatum(data);
808 : }
809 348 : if (exprs != (Datum) 0)
810 : {
811 150 : nulls[Anum_pg_statistic_ext_data_stxdexpr - 1] = false;
812 150 : values[Anum_pg_statistic_ext_data_stxdexpr - 1] = exprs;
813 : }
814 :
815 : /*
816 : * Delete the old tuple if it exists, and insert a new one. It's easier
817 : * than trying to update or insert, based on various conditions.
818 : */
819 348 : RemoveStatisticsDataById(statOid, inh);
820 :
821 : /* form and insert a new tuple */
822 348 : stup = heap_form_tuple(RelationGetDescr(pg_stextdata), values, nulls);
823 348 : CatalogTupleInsert(pg_stextdata, stup);
824 :
825 348 : heap_freetuple(stup);
826 :
827 348 : table_close(pg_stextdata, RowExclusiveLock);
828 348 : }
829 :
830 : /* initialize multi-dimensional sort */
831 : MultiSortSupport
832 1260 : multi_sort_init(int ndims)
833 : {
834 : MultiSortSupport mss;
835 :
836 : Assert(ndims >= 2);
837 :
838 1260 : mss = (MultiSortSupport) palloc0(offsetof(MultiSortSupportData, ssup)
839 1260 : + sizeof(SortSupportData) * ndims);
840 :
841 1260 : mss->ndims = ndims;
842 :
843 1260 : return mss;
844 : }
845 :
846 : /*
847 : * Prepare sort support info using the given sort operator and collation
848 : * at the position 'sortdim'
849 : */
850 : void
851 2994 : multi_sort_add_dimension(MultiSortSupport mss, int sortdim,
852 : Oid oper, Oid collation)
853 : {
854 2994 : SortSupport ssup = &mss->ssup[sortdim];
855 :
856 2994 : ssup->ssup_cxt = CurrentMemoryContext;
857 2994 : ssup->ssup_collation = collation;
858 2994 : ssup->ssup_nulls_first = false;
859 :
860 2994 : PrepareSortSupportFromOrderingOp(oper, ssup);
861 2994 : }
862 :
863 : /* compare all the dimensions in the selected order */
864 : int
865 15215334 : multi_sort_compare(const void *a, const void *b, void *arg)
866 : {
867 15215334 : MultiSortSupport mss = (MultiSortSupport) arg;
868 15215334 : SortItem *ia = (SortItem *) a;
869 15215334 : SortItem *ib = (SortItem *) b;
870 : int i;
871 :
872 27545556 : for (i = 0; i < mss->ndims; i++)
873 : {
874 : int compare;
875 :
876 23966712 : compare = ApplySortComparator(ia->values[i], ia->isnull[i],
877 23966712 : ib->values[i], ib->isnull[i],
878 23966712 : &mss->ssup[i]);
879 :
880 23966712 : if (compare != 0)
881 11636490 : return compare;
882 : }
883 :
884 : /* equal by default */
885 3578844 : return 0;
886 : }
887 :
888 : /* compare selected dimension */
889 : int
890 1472580 : multi_sort_compare_dim(int dim, const SortItem *a, const SortItem *b,
891 : MultiSortSupport mss)
892 : {
893 2945160 : return ApplySortComparator(a->values[dim], a->isnull[dim],
894 1472580 : b->values[dim], b->isnull[dim],
895 1472580 : &mss->ssup[dim]);
896 : }
897 :
898 : int
899 1504218 : multi_sort_compare_dims(int start, int end,
900 : const SortItem *a, const SortItem *b,
901 : MultiSortSupport mss)
902 : {
903 : int dim;
904 :
905 3403332 : for (dim = start; dim <= end; dim++)
906 : {
907 1930752 : int r = ApplySortComparator(a->values[dim], a->isnull[dim],
908 1930752 : b->values[dim], b->isnull[dim],
909 1930752 : &mss->ssup[dim]);
910 :
911 1930752 : if (r != 0)
912 31638 : return r;
913 : }
914 :
915 1472580 : return 0;
916 : }
917 :
918 : int
919 187380 : compare_scalars_simple(const void *a, const void *b, void *arg)
920 : {
921 187380 : return compare_datums_simple(*(Datum *) a,
922 : *(Datum *) b,
923 : (SortSupport) arg);
924 : }
925 :
926 : int
927 211068 : compare_datums_simple(Datum a, Datum b, SortSupport ssup)
928 : {
929 211068 : return ApplySortComparator(a, false, b, false, ssup);
930 : }
931 :
932 : /*
933 : * build_attnums_array
934 : * Transforms a bitmap into an array of AttrNumber values.
935 : *
936 : * This is used for extended statistics only, so all the attributes must be
937 : * user-defined. That means offsetting by FirstLowInvalidHeapAttributeNumber
938 : * is not necessary here (and when querying the bitmap).
939 : */
940 : AttrNumber *
941 0 : build_attnums_array(Bitmapset *attrs, int nexprs, int *numattrs)
942 : {
943 : int i,
944 : j;
945 : AttrNumber *attnums;
946 0 : int num = bms_num_members(attrs);
947 :
948 0 : if (numattrs)
949 0 : *numattrs = num;
950 :
951 : /* build attnums from the bitmapset */
952 0 : attnums = (AttrNumber *) palloc(sizeof(AttrNumber) * num);
953 0 : i = 0;
954 0 : j = -1;
955 0 : while ((j = bms_next_member(attrs, j)) >= 0)
956 : {
957 0 : int attnum = (j - nexprs);
958 :
959 : /*
960 : * Make sure the bitmap contains only user-defined attributes. As
961 : * bitmaps can't contain negative values, this can be violated in two
962 : * ways. Firstly, the bitmap might contain 0 as a member, and secondly
963 : * the integer value might be larger than MaxAttrNumber.
964 : */
965 : Assert(AttributeNumberIsValid(attnum));
966 : Assert(attnum <= MaxAttrNumber);
967 : Assert(attnum >= (-nexprs));
968 :
969 0 : attnums[i++] = (AttrNumber) attnum;
970 :
971 : /* protect against overflows */
972 : Assert(i <= num);
973 : }
974 :
975 0 : return attnums;
976 : }
977 :
978 : /*
979 : * build_sorted_items
980 : * build a sorted array of SortItem with values from rows
981 : *
982 : * Note: All the memory is allocated in a single chunk, so that the caller
983 : * can simply pfree the return value to release all of it.
984 : */
985 : SortItem *
986 756 : build_sorted_items(StatsBuildData *data, int *nitems,
987 : MultiSortSupport mss,
988 : int numattrs, AttrNumber *attnums)
989 : {
990 : int i,
991 : j,
992 : len,
993 : nrows;
994 756 : int nvalues = data->numrows * numattrs;
995 :
996 : SortItem *items;
997 : Datum *values;
998 : bool *isnull;
999 : char *ptr;
1000 : int *typlen;
1001 :
1002 : /* Compute the total amount of memory we need (both items and values). */
1003 756 : len = data->numrows * sizeof(SortItem) + nvalues * (sizeof(Datum) + sizeof(bool));
1004 :
1005 : /* Allocate the memory and split it into the pieces. */
1006 756 : ptr = palloc0(len);
1007 :
1008 : /* items to sort */
1009 756 : items = (SortItem *) ptr;
1010 756 : ptr += data->numrows * sizeof(SortItem);
1011 :
1012 : /* values and null flags */
1013 756 : values = (Datum *) ptr;
1014 756 : ptr += nvalues * sizeof(Datum);
1015 :
1016 756 : isnull = (bool *) ptr;
1017 756 : ptr += nvalues * sizeof(bool);
1018 :
1019 : /* make sure we consumed the whole buffer exactly */
1020 : Assert((ptr - (char *) items) == len);
1021 :
1022 : /* fix the pointers to Datum and bool arrays */
1023 756 : nrows = 0;
1024 1964568 : for (i = 0; i < data->numrows; i++)
1025 : {
1026 1963812 : items[nrows].values = &values[nrows * numattrs];
1027 1963812 : items[nrows].isnull = &isnull[nrows * numattrs];
1028 :
1029 1963812 : nrows++;
1030 : }
1031 :
1032 : /* build a local cache of typlen for all attributes */
1033 756 : typlen = (int *) palloc(sizeof(int) * data->nattnums);
1034 2850 : for (i = 0; i < data->nattnums; i++)
1035 2094 : typlen[i] = get_typlen(data->stats[i]->attrtypid);
1036 :
1037 756 : nrows = 0;
1038 1964568 : for (i = 0; i < data->numrows; i++)
1039 : {
1040 1963812 : bool toowide = false;
1041 :
1042 : /* load the values/null flags from sample rows */
1043 6768012 : for (j = 0; j < numattrs; j++)
1044 : {
1045 : Datum value;
1046 : bool isnull;
1047 : int attlen;
1048 4804200 : AttrNumber attnum = attnums[j];
1049 :
1050 : int idx;
1051 :
1052 : /* match attnum to the pre-calculated data */
1053 9493128 : for (idx = 0; idx < data->nattnums; idx++)
1054 : {
1055 9493128 : if (attnum == data->attnums[idx])
1056 4804200 : break;
1057 : }
1058 :
1059 : Assert(idx < data->nattnums);
1060 :
1061 4804200 : value = data->values[idx][i];
1062 4804200 : isnull = data->nulls[idx][i];
1063 4804200 : attlen = typlen[idx];
1064 :
1065 : /*
1066 : * If this is a varlena value, check if it's too wide and if yes
1067 : * then skip the whole item. Otherwise detoast the value.
1068 : *
1069 : * XXX It may happen that we've already detoasted some preceding
1070 : * values for the current item. We don't bother to cleanup those
1071 : * on the assumption that those are small (below WIDTH_THRESHOLD)
1072 : * and will be discarded at the end of analyze.
1073 : */
1074 4804200 : if ((!isnull) && (attlen == -1))
1075 : {
1076 1480200 : if (toast_raw_datum_size(value) > WIDTH_THRESHOLD)
1077 : {
1078 0 : toowide = true;
1079 0 : break;
1080 : }
1081 :
1082 1480200 : value = PointerGetDatum(PG_DETOAST_DATUM(value));
1083 : }
1084 :
1085 4804200 : items[nrows].values[j] = value;
1086 4804200 : items[nrows].isnull[j] = isnull;
1087 : }
1088 :
1089 1963812 : if (toowide)
1090 0 : continue;
1091 :
1092 1963812 : nrows++;
1093 : }
1094 :
1095 : /* store the actual number of items (ignoring the too-wide ones) */
1096 756 : *nitems = nrows;
1097 :
1098 : /* all items were too wide */
1099 756 : if (nrows == 0)
1100 : {
1101 : /* everything is allocated as a single chunk */
1102 0 : pfree(items);
1103 0 : return NULL;
1104 : }
1105 :
1106 : /* do the sort, using the multi-sort */
1107 756 : qsort_interruptible(items, nrows, sizeof(SortItem),
1108 : multi_sort_compare, mss);
1109 :
1110 756 : return items;
1111 : }
1112 :
1113 : /*
1114 : * has_stats_of_kind
1115 : * Check whether the list contains statistic of a given kind
1116 : */
1117 : bool
1118 3576 : has_stats_of_kind(List *stats, char requiredkind)
1119 : {
1120 : ListCell *l;
1121 :
1122 6006 : foreach(l, stats)
1123 : {
1124 4212 : StatisticExtInfo *stat = (StatisticExtInfo *) lfirst(l);
1125 :
1126 4212 : if (stat->kind == requiredkind)
1127 1782 : return true;
1128 : }
1129 :
1130 1794 : return false;
1131 : }
1132 :
1133 : /*
1134 : * stat_find_expression
1135 : * Search for an expression in statistics object's list of expressions.
1136 : *
1137 : * Returns the index of the expression in the statistics object's list of
1138 : * expressions, or -1 if not found.
1139 : */
1140 : static int
1141 516 : stat_find_expression(StatisticExtInfo *stat, Node *expr)
1142 : {
1143 : ListCell *lc;
1144 : int idx;
1145 :
1146 516 : idx = 0;
1147 996 : foreach(lc, stat->exprs)
1148 : {
1149 972 : Node *stat_expr = (Node *) lfirst(lc);
1150 :
1151 972 : if (equal(stat_expr, expr))
1152 492 : return idx;
1153 480 : idx++;
1154 : }
1155 :
1156 : /* Expression not found */
1157 24 : return -1;
1158 : }
1159 :
1160 : /*
1161 : * stat_covers_expressions
1162 : * Test whether a statistics object covers all expressions in a list.
1163 : *
1164 : * Returns true if all expressions are covered. If expr_idxs is non-NULL, it
1165 : * is populated with the indexes of the expressions found.
1166 : */
1167 : static bool
1168 2388 : stat_covers_expressions(StatisticExtInfo *stat, List *exprs,
1169 : Bitmapset **expr_idxs)
1170 : {
1171 : ListCell *lc;
1172 :
1173 2880 : foreach(lc, exprs)
1174 : {
1175 516 : Node *expr = (Node *) lfirst(lc);
1176 : int expr_idx;
1177 :
1178 516 : expr_idx = stat_find_expression(stat, expr);
1179 516 : if (expr_idx == -1)
1180 24 : return false;
1181 :
1182 492 : if (expr_idxs != NULL)
1183 246 : *expr_idxs = bms_add_member(*expr_idxs, expr_idx);
1184 : }
1185 :
1186 : /* If we reach here, all expressions are covered */
1187 2364 : return true;
1188 : }
1189 :
1190 : /*
1191 : * choose_best_statistics
1192 : * Look for and return statistics with the specified 'requiredkind' which
1193 : * have keys that match at least two of the given attnums. Return NULL if
1194 : * there's no match.
1195 : *
1196 : * The current selection criteria is very simple - we choose the statistics
1197 : * object referencing the most attributes in covered (and still unestimated
1198 : * clauses), breaking ties in favor of objects with fewer keys overall.
1199 : *
1200 : * The clause_attnums is an array of bitmaps, storing attnums for individual
1201 : * clauses. A NULL element means the clause is either incompatible or already
1202 : * estimated.
1203 : *
1204 : * XXX If multiple statistics objects tie on both criteria, then which object
1205 : * is chosen depends on the order that they appear in the stats list. Perhaps
1206 : * further tiebreakers are needed.
1207 : */
1208 : StatisticExtInfo *
1209 978 : choose_best_statistics(List *stats, char requiredkind, bool inh,
1210 : Bitmapset **clause_attnums, List **clause_exprs,
1211 : int nclauses)
1212 : {
1213 : ListCell *lc;
1214 978 : StatisticExtInfo *best_match = NULL;
1215 978 : int best_num_matched = 2; /* goal #1: maximize */
1216 978 : int best_match_keys = (STATS_MAX_DIMENSIONS + 1); /* goal #2: minimize */
1217 :
1218 2550 : foreach(lc, stats)
1219 : {
1220 : int i;
1221 1572 : StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
1222 1572 : Bitmapset *matched_attnums = NULL;
1223 1572 : Bitmapset *matched_exprs = NULL;
1224 : int num_matched;
1225 : int numkeys;
1226 :
1227 : /* skip statistics that are not of the correct type */
1228 1572 : if (info->kind != requiredkind)
1229 468 : continue;
1230 :
1231 : /* skip statistics with mismatching inheritance flag */
1232 1104 : if (info->inherit != inh)
1233 24 : continue;
1234 :
1235 : /*
1236 : * Collect attributes and expressions in remaining (unestimated)
1237 : * clauses fully covered by this statistic object.
1238 : *
1239 : * We know already estimated clauses have both clause_attnums and
1240 : * clause_exprs set to NULL. We leave the pointers NULL if already
1241 : * estimated, or we reset them to NULL after estimating the clause.
1242 : */
1243 3864 : for (i = 0; i < nclauses; i++)
1244 : {
1245 2784 : Bitmapset *expr_idxs = NULL;
1246 :
1247 : /* ignore incompatible/estimated clauses */
1248 2784 : if (!clause_attnums[i] && !clause_exprs[i])
1249 1572 : continue;
1250 :
1251 : /* ignore clauses that are not covered by this object */
1252 1422 : if (!bms_is_subset(clause_attnums[i], info->keys) ||
1253 1230 : !stat_covers_expressions(info, clause_exprs[i], &expr_idxs))
1254 210 : continue;
1255 :
1256 : /* record attnums and indexes of expressions covered */
1257 1212 : matched_attnums = bms_add_members(matched_attnums, clause_attnums[i]);
1258 1212 : matched_exprs = bms_add_members(matched_exprs, expr_idxs);
1259 : }
1260 :
1261 1080 : num_matched = bms_num_members(matched_attnums) + bms_num_members(matched_exprs);
1262 :
1263 1080 : bms_free(matched_attnums);
1264 1080 : bms_free(matched_exprs);
1265 :
1266 : /*
1267 : * save the actual number of keys in the stats so that we can choose
1268 : * the narrowest stats with the most matching keys.
1269 : */
1270 1080 : numkeys = bms_num_members(info->keys) + list_length(info->exprs);
1271 :
1272 : /*
1273 : * Use this object when it increases the number of matched attributes
1274 : * and expressions or when it matches the same number of attributes
1275 : * and expressions but these stats have fewer keys than any previous
1276 : * match.
1277 : */
1278 1080 : if (num_matched > best_num_matched ||
1279 282 : (num_matched == best_num_matched && numkeys < best_match_keys))
1280 : {
1281 480 : best_match = info;
1282 480 : best_num_matched = num_matched;
1283 480 : best_match_keys = numkeys;
1284 : }
1285 : }
1286 :
1287 978 : return best_match;
1288 : }
1289 :
1290 : /*
1291 : * statext_is_compatible_clause_internal
1292 : * Determines if the clause is compatible with MCV lists.
1293 : *
1294 : * To be compatible, the given clause must be a combination of supported
1295 : * clauses built from Vars or sub-expressions (where a sub-expression is
1296 : * something that exactly matches an expression found in statistics objects).
1297 : * This function recursively examines the clause and extracts any
1298 : * sub-expressions that will need to be matched against statistics.
1299 : *
1300 : * Currently, we only support the following types of clauses:
1301 : *
1302 : * (a) OpExprs of the form (Var/Expr op Const), or (Const op Var/Expr), where
1303 : * the op is one of ("=", "<", ">", ">=", "<=")
1304 : *
1305 : * (b) (Var/Expr IS [NOT] NULL)
1306 : *
1307 : * (c) combinations using AND/OR/NOT
1308 : *
1309 : * (d) ScalarArrayOpExprs of the form (Var/Expr op ANY (Const)) or
1310 : * (Var/Expr op ALL (Const))
1311 : *
1312 : * In the future, the range of supported clauses may be expanded to more
1313 : * complex cases, for example (Var op Var).
1314 : *
1315 : * Arguments:
1316 : * clause: (sub)clause to be inspected (bare clause, not a RestrictInfo)
1317 : * relid: rel that all Vars in clause must belong to
1318 : * *attnums: input/output parameter collecting attribute numbers of all
1319 : * mentioned Vars. Note that we do not offset the attribute numbers,
1320 : * so we can't cope with system columns.
1321 : * *exprs: input/output parameter collecting primitive subclauses within
1322 : * the clause tree
1323 : *
1324 : * Returns false if there is something we definitively can't handle.
1325 : * On true return, we can proceed to match the *exprs against statistics.
1326 : */
1327 : static bool
1328 2364 : statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
1329 : Index relid, Bitmapset **attnums,
1330 : List **exprs)
1331 : {
1332 : /* Look inside any binary-compatible relabeling (as in examine_variable) */
1333 2364 : if (IsA(clause, RelabelType))
1334 0 : clause = (Node *) ((RelabelType *) clause)->arg;
1335 :
1336 : /* plain Var references (boolean Vars or recursive checks) */
1337 2364 : if (IsA(clause, Var))
1338 : {
1339 1068 : Var *var = (Var *) clause;
1340 :
1341 : /* Ensure var is from the correct relation */
1342 1068 : if (var->varno != relid)
1343 0 : return false;
1344 :
1345 : /* we also better ensure the Var is from the current level */
1346 1068 : if (var->varlevelsup > 0)
1347 0 : return false;
1348 :
1349 : /*
1350 : * Also reject system attributes and whole-row Vars (we don't allow
1351 : * stats on those).
1352 : */
1353 1068 : if (!AttrNumberIsForUserDefinedAttr(var->varattno))
1354 0 : return false;
1355 :
1356 : /* OK, record the attnum for later permissions checks. */
1357 1068 : *attnums = bms_add_member(*attnums, var->varattno);
1358 :
1359 1068 : return true;
1360 : }
1361 :
1362 : /* (Var/Expr op Const) or (Const op Var/Expr) */
1363 1296 : if (is_opclause(clause))
1364 : {
1365 936 : RangeTblEntry *rte = root->simple_rte_array[relid];
1366 936 : OpExpr *expr = (OpExpr *) clause;
1367 : Node *clause_expr;
1368 :
1369 : /* Only expressions with two arguments are considered compatible. */
1370 936 : if (list_length(expr->args) != 2)
1371 0 : return false;
1372 :
1373 : /* Check if the expression has the right shape */
1374 936 : if (!examine_opclause_args(expr->args, &clause_expr, NULL, NULL))
1375 0 : return false;
1376 :
1377 : /*
1378 : * If it's not one of the supported operators ("=", "<", ">", etc.),
1379 : * just ignore the clause, as it's not compatible with MCV lists.
1380 : *
1381 : * This uses the function for estimating selectivity, not the operator
1382 : * directly (a bit awkward, but well ...).
1383 : */
1384 936 : switch (get_oprrest(expr->opno))
1385 : {
1386 936 : case F_EQSEL:
1387 : case F_NEQSEL:
1388 : case F_SCALARLTSEL:
1389 : case F_SCALARLESEL:
1390 : case F_SCALARGTSEL:
1391 : case F_SCALARGESEL:
1392 : /* supported, will continue with inspection of the Var/Expr */
1393 936 : break;
1394 :
1395 0 : default:
1396 : /* other estimators are considered unknown/unsupported */
1397 0 : return false;
1398 : }
1399 :
1400 : /*
1401 : * If there are any securityQuals on the RTE from security barrier
1402 : * views or RLS policies, then the user may not have access to all the
1403 : * table's data, and we must check that the operator is leak-proof.
1404 : *
1405 : * If the operator is leaky, then we must ignore this clause for the
1406 : * purposes of estimating with MCV lists, otherwise the operator might
1407 : * reveal values from the MCV list that the user doesn't have
1408 : * permission to see.
1409 : */
1410 936 : if (rte->securityQuals != NIL &&
1411 0 : !get_func_leakproof(get_opcode(expr->opno)))
1412 0 : return false;
1413 :
1414 : /* Check (Var op Const) or (Const op Var) clauses by recursing. */
1415 936 : if (IsA(clause_expr, Var))
1416 744 : return statext_is_compatible_clause_internal(root, clause_expr,
1417 : relid, attnums, exprs);
1418 :
1419 : /* Otherwise we have (Expr op Const) or (Const op Expr). */
1420 192 : *exprs = lappend(*exprs, clause_expr);
1421 192 : return true;
1422 : }
1423 :
1424 : /* Var/Expr IN Array */
1425 360 : if (IsA(clause, ScalarArrayOpExpr))
1426 : {
1427 216 : RangeTblEntry *rte = root->simple_rte_array[relid];
1428 216 : ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) clause;
1429 : Node *clause_expr;
1430 : bool expronleft;
1431 :
1432 : /* Only expressions with two arguments are considered compatible. */
1433 216 : 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 216 : 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 216 : if (!expronleft)
1442 6 : 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 210 : switch (get_oprrest(expr->opno))
1452 : {
1453 210 : 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 210 : break;
1461 :
1462 0 : default:
1463 : /* other estimators are considered unknown/unsupported */
1464 0 : return false;
1465 : }
1466 :
1467 : /*
1468 : * If there are any securityQuals on the RTE from security barrier
1469 : * views or RLS policies, then the user may not have access to all the
1470 : * table's data, and we must check that the operator is leak-proof.
1471 : *
1472 : * If the operator is leaky, then we must ignore this clause for the
1473 : * purposes of estimating with MCV lists, otherwise the operator might
1474 : * reveal values from the MCV list that the user doesn't have
1475 : * permission to see.
1476 : */
1477 210 : if (rte->securityQuals != NIL &&
1478 0 : !get_func_leakproof(get_opcode(expr->opno)))
1479 0 : return false;
1480 :
1481 : /* Check Var IN Array clauses by recursing. */
1482 210 : if (IsA(clause_expr, Var))
1483 156 : return statext_is_compatible_clause_internal(root, clause_expr,
1484 : relid, attnums, exprs);
1485 :
1486 : /* Otherwise we have Expr IN Array. */
1487 54 : *exprs = lappend(*exprs, clause_expr);
1488 54 : return true;
1489 : }
1490 :
1491 : /* AND/OR/NOT clause */
1492 288 : if (is_andclause(clause) ||
1493 276 : is_orclause(clause) ||
1494 132 : is_notclause(clause))
1495 : {
1496 : /*
1497 : * AND/OR/NOT-clauses are supported if all sub-clauses are supported
1498 : *
1499 : * Perhaps we could improve this by handling mixed cases, when some of
1500 : * the clauses are supported and some are not. Selectivity for the
1501 : * supported subclauses would be computed using extended statistics,
1502 : * and the remaining clauses would be estimated using the traditional
1503 : * algorithm (product of selectivities).
1504 : *
1505 : * It however seems overly complex, and in a way we already do that
1506 : * because if we reject the whole clause as unsupported here, it will
1507 : * be eventually passed to clauselist_selectivity() which does exactly
1508 : * this (split into supported/unsupported clauses etc).
1509 : */
1510 42 : BoolExpr *expr = (BoolExpr *) clause;
1511 : ListCell *lc;
1512 :
1513 96 : foreach(lc, expr->args)
1514 : {
1515 : /*
1516 : * If we find an incompatible clause in the arguments, treat the
1517 : * whole clause as incompatible.
1518 : */
1519 54 : if (!statext_is_compatible_clause_internal(root,
1520 54 : (Node *) lfirst(lc),
1521 : relid, attnums, exprs))
1522 0 : return false;
1523 : }
1524 :
1525 42 : return true;
1526 : }
1527 :
1528 : /* Var/Expr IS NULL */
1529 102 : if (IsA(clause, NullTest))
1530 : {
1531 96 : NullTest *nt = (NullTest *) clause;
1532 :
1533 : /* Check Var IS NULL clauses by recursing. */
1534 96 : if (IsA(nt->arg, Var))
1535 90 : return statext_is_compatible_clause_internal(root, (Node *) (nt->arg),
1536 : relid, attnums, exprs);
1537 :
1538 : /* Otherwise we have Expr IS NULL. */
1539 6 : *exprs = lappend(*exprs, nt->arg);
1540 6 : return true;
1541 : }
1542 :
1543 : /*
1544 : * Treat any other expressions as bare expressions to be matched against
1545 : * expressions in statistics objects.
1546 : */
1547 6 : *exprs = lappend(*exprs, clause);
1548 6 : return true;
1549 : }
1550 :
1551 : /*
1552 : * statext_is_compatible_clause
1553 : * Determines if the clause is compatible with MCV lists.
1554 : *
1555 : * See statext_is_compatible_clause_internal, above, for the basic rules.
1556 : * This layer deals with RestrictInfo superstructure and applies permissions
1557 : * checks to verify that it's okay to examine all mentioned Vars.
1558 : *
1559 : * Arguments:
1560 : * clause: clause to be inspected (in RestrictInfo form)
1561 : * relid: rel that all Vars in clause must belong to
1562 : * *attnums: input/output parameter collecting attribute numbers of all
1563 : * mentioned Vars. Note that we do not offset the attribute numbers,
1564 : * so we can't cope with system columns.
1565 : * *exprs: input/output parameter collecting primitive subclauses within
1566 : * the clause tree
1567 : *
1568 : * Returns false if there is something we definitively can't handle.
1569 : * On true return, we can proceed to match the *exprs against statistics.
1570 : */
1571 : static bool
1572 1374 : statext_is_compatible_clause(PlannerInfo *root, Node *clause, Index relid,
1573 : Bitmapset **attnums, List **exprs)
1574 : {
1575 1374 : RangeTblEntry *rte = root->simple_rte_array[relid];
1576 1374 : RelOptInfo *rel = root->simple_rel_array[relid];
1577 : RestrictInfo *rinfo;
1578 : int clause_relid;
1579 : Oid userid;
1580 :
1581 : /*
1582 : * Special-case handling for bare BoolExpr AND clauses, because the
1583 : * restrictinfo machinery doesn't build RestrictInfos on top of AND
1584 : * clauses.
1585 : */
1586 1374 : if (is_andclause(clause))
1587 : {
1588 48 : BoolExpr *expr = (BoolExpr *) clause;
1589 : ListCell *lc;
1590 :
1591 : /*
1592 : * Check that each sub-clause is compatible. We expect these to be
1593 : * RestrictInfos.
1594 : */
1595 162 : foreach(lc, expr->args)
1596 : {
1597 114 : if (!statext_is_compatible_clause(root, (Node *) lfirst(lc),
1598 : relid, attnums, exprs))
1599 0 : return false;
1600 : }
1601 :
1602 48 : return true;
1603 : }
1604 :
1605 : /* Otherwise it must be a RestrictInfo. */
1606 1326 : if (!IsA(clause, RestrictInfo))
1607 0 : return false;
1608 1326 : rinfo = (RestrictInfo *) clause;
1609 :
1610 : /* Pseudoconstants are not really interesting here. */
1611 1326 : if (rinfo->pseudoconstant)
1612 6 : return false;
1613 :
1614 : /* Clauses referencing other varnos are incompatible. */
1615 1320 : if (!bms_get_singleton_member(rinfo->clause_relids, &clause_relid) ||
1616 1320 : clause_relid != relid)
1617 0 : return false;
1618 :
1619 : /* Check the clause and determine what attributes it references. */
1620 1320 : if (!statext_is_compatible_clause_internal(root, (Node *) rinfo->clause,
1621 : relid, attnums, exprs))
1622 6 : return false;
1623 :
1624 : /*
1625 : * Check that the user has permission to read all required attributes.
1626 : */
1627 1314 : userid = OidIsValid(rel->userid) ? rel->userid : GetUserId();
1628 :
1629 : /* Table-level SELECT privilege is sufficient for all columns */
1630 1314 : if (pg_class_aclcheck(rte->relid, userid, ACL_SELECT) != ACLCHECK_OK)
1631 : {
1632 36 : Bitmapset *clause_attnums = NULL;
1633 36 : int attnum = -1;
1634 :
1635 : /*
1636 : * We have to check per-column privileges. *attnums has the attnums
1637 : * for individual Vars we saw, but there may also be Vars within
1638 : * subexpressions in *exprs. We can use pull_varattnos() to extract
1639 : * those, but there's an impedance mismatch: attnums returned by
1640 : * pull_varattnos() are offset by FirstLowInvalidHeapAttributeNumber,
1641 : * while attnums within *attnums aren't. Convert *attnums to the
1642 : * offset style so we can combine the results.
1643 : */
1644 66 : while ((attnum = bms_next_member(*attnums, attnum)) >= 0)
1645 : {
1646 30 : clause_attnums =
1647 30 : bms_add_member(clause_attnums,
1648 : attnum - FirstLowInvalidHeapAttributeNumber);
1649 : }
1650 :
1651 : /* Now merge attnums from *exprs into clause_attnums */
1652 36 : if (*exprs != NIL)
1653 6 : pull_varattnos((Node *) *exprs, relid, &clause_attnums);
1654 :
1655 36 : attnum = -1;
1656 36 : while ((attnum = bms_next_member(clause_attnums, attnum)) >= 0)
1657 : {
1658 : /* Undo the offset */
1659 36 : AttrNumber attno = attnum + FirstLowInvalidHeapAttributeNumber;
1660 :
1661 36 : if (attno == InvalidAttrNumber)
1662 : {
1663 : /* Whole-row reference, so must have access to all columns */
1664 6 : if (pg_attribute_aclcheck_all(rte->relid, userid, ACL_SELECT,
1665 : ACLMASK_ALL) != ACLCHECK_OK)
1666 36 : return false;
1667 : }
1668 : else
1669 : {
1670 30 : if (pg_attribute_aclcheck(rte->relid, attno, userid,
1671 : ACL_SELECT) != ACLCHECK_OK)
1672 30 : return false;
1673 : }
1674 : }
1675 : }
1676 :
1677 : /* If we reach here, the clause is OK */
1678 1278 : return true;
1679 : }
1680 :
1681 : /*
1682 : * statext_mcv_clauselist_selectivity
1683 : * Estimate clauses using the best multi-column statistics.
1684 : *
1685 : * Applies available extended (multi-column) statistics on a table. There may
1686 : * be multiple applicable statistics (with respect to the clauses), in which
1687 : * case we use greedy approach. In each round we select the best statistic on
1688 : * a table (measured by the number of attributes extracted from the clauses
1689 : * and covered by it), and compute the selectivity for the supplied clauses.
1690 : * We repeat this process with the remaining clauses (if any), until none of
1691 : * the available statistics can be used.
1692 : *
1693 : * One of the main challenges with using MCV lists is how to extrapolate the
1694 : * estimate to the data not covered by the MCV list. To do that, we compute
1695 : * not only the "MCV selectivity" (selectivities for MCV items matching the
1696 : * supplied clauses), but also the following related selectivities:
1697 : *
1698 : * - simple selectivity: Computed without extended statistics, i.e. as if the
1699 : * columns/clauses were independent.
1700 : *
1701 : * - base selectivity: Similar to simple selectivity, but is computed using
1702 : * the extended statistic by adding up the base frequencies (that we compute
1703 : * and store for each MCV item) of matching MCV items.
1704 : *
1705 : * - total selectivity: Selectivity covered by the whole MCV list.
1706 : *
1707 : * These are passed to mcv_combine_selectivities() which combines them to
1708 : * produce a selectivity estimate that makes use of both per-column statistics
1709 : * and the multi-column MCV statistics.
1710 : *
1711 : * 'estimatedclauses' is an input/output parameter. We set bits for the
1712 : * 0-based 'clauses' indexes we estimate for and also skip clause items that
1713 : * already have a bit set.
1714 : */
1715 : static Selectivity
1716 1842 : statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
1717 : JoinType jointype, SpecialJoinInfo *sjinfo,
1718 : RelOptInfo *rel, Bitmapset **estimatedclauses,
1719 : bool is_or)
1720 : {
1721 : ListCell *l;
1722 : Bitmapset **list_attnums; /* attnums extracted from the clause */
1723 : List **list_exprs; /* expressions matched to any statistic */
1724 : int listidx;
1725 1842 : Selectivity sel = (is_or) ? 0.0 : 1.0;
1726 1842 : RangeTblEntry *rte = planner_rt_fetch(rel->relid, root);
1727 :
1728 : /* check if there's any stats that might be useful for us. */
1729 1842 : if (!has_stats_of_kind(rel->statlist, STATS_EXT_MCV))
1730 1344 : return sel;
1731 :
1732 498 : list_attnums = (Bitmapset **) palloc(sizeof(Bitmapset *) *
1733 498 : list_length(clauses));
1734 :
1735 : /* expressions extracted from complex expressions */
1736 498 : list_exprs = (List **) palloc(sizeof(Node *) * list_length(clauses));
1737 :
1738 : /*
1739 : * Pre-process the clauses list to extract the attnums and expressions
1740 : * seen in each item. We need to determine if there are any clauses which
1741 : * will be useful for selectivity estimations with extended stats. Along
1742 : * the way we'll record all of the attnums and expressions for each clause
1743 : * in lists which we'll reference later so we don't need to repeat the
1744 : * same work again.
1745 : *
1746 : * We also skip clauses that we already estimated using different types of
1747 : * statistics (we treat them as incompatible).
1748 : */
1749 498 : listidx = 0;
1750 1758 : foreach(l, clauses)
1751 : {
1752 1260 : Node *clause = (Node *) lfirst(l);
1753 1260 : Bitmapset *attnums = NULL;
1754 1260 : List *exprs = NIL;
1755 :
1756 2520 : if (!bms_is_member(listidx, *estimatedclauses) &&
1757 1260 : statext_is_compatible_clause(root, clause, rel->relid, &attnums, &exprs))
1758 : {
1759 1212 : list_attnums[listidx] = attnums;
1760 1212 : list_exprs[listidx] = exprs;
1761 : }
1762 : else
1763 : {
1764 48 : list_attnums[listidx] = NULL;
1765 48 : list_exprs[listidx] = NIL;
1766 : }
1767 :
1768 1260 : listidx++;
1769 : }
1770 :
1771 : /* apply as many extended statistics as possible */
1772 : while (true)
1773 480 : {
1774 : StatisticExtInfo *stat;
1775 : List *stat_clauses;
1776 : Bitmapset *simple_clauses;
1777 :
1778 : /* find the best suited statistics object for these attnums */
1779 978 : stat = choose_best_statistics(rel->statlist, STATS_EXT_MCV, rte->inh,
1780 : list_attnums, list_exprs,
1781 : list_length(clauses));
1782 :
1783 : /*
1784 : * if no (additional) matching stats could be found then we've nothing
1785 : * to do
1786 : */
1787 978 : if (!stat)
1788 498 : break;
1789 :
1790 : /* Ensure choose_best_statistics produced an expected stats type. */
1791 : Assert(stat->kind == STATS_EXT_MCV);
1792 :
1793 : /* now filter the clauses to be estimated using the selected MCV */
1794 480 : stat_clauses = NIL;
1795 :
1796 : /* record which clauses are simple (single column or expression) */
1797 480 : simple_clauses = NULL;
1798 :
1799 480 : listidx = -1;
1800 1728 : foreach(l, clauses)
1801 : {
1802 : /* Increment the index before we decide if to skip the clause. */
1803 1248 : listidx++;
1804 :
1805 : /*
1806 : * Ignore clauses from which we did not extract any attnums or
1807 : * expressions (this needs to be consistent with what we do in
1808 : * choose_best_statistics).
1809 : *
1810 : * This also eliminates already estimated clauses - both those
1811 : * estimated before and during applying extended statistics.
1812 : *
1813 : * XXX This check is needed because both bms_is_subset and
1814 : * stat_covers_expressions return true for empty attnums and
1815 : * expressions.
1816 : */
1817 1248 : if (!list_attnums[listidx] && !list_exprs[listidx])
1818 36 : continue;
1819 :
1820 : /*
1821 : * The clause was not estimated yet, and we've extracted either
1822 : * attnums or expressions from it. Ignore it if it's not fully
1823 : * covered by the chosen statistics object.
1824 : *
1825 : * We need to check both attributes and expressions, and reject if
1826 : * either is not covered.
1827 : */
1828 1212 : if (!bms_is_subset(list_attnums[listidx], stat->keys) ||
1829 1158 : !stat_covers_expressions(stat, list_exprs[listidx], NULL))
1830 60 : continue;
1831 :
1832 : /*
1833 : * Now we know the clause is compatible (we have either attnums or
1834 : * expressions extracted from it), and was not estimated yet.
1835 : */
1836 :
1837 : /* record simple clauses (single column or expression) */
1838 1398 : if ((list_attnums[listidx] == NULL &&
1839 246 : list_length(list_exprs[listidx]) == 1) ||
1840 1812 : (list_exprs[listidx] == NIL &&
1841 906 : bms_membership(list_attnums[listidx]) == BMS_SINGLETON))
1842 1092 : simple_clauses = bms_add_member(simple_clauses,
1843 : list_length(stat_clauses));
1844 :
1845 : /* add clause to list and mark it as estimated */
1846 1152 : stat_clauses = lappend(stat_clauses, (Node *) lfirst(l));
1847 1152 : *estimatedclauses = bms_add_member(*estimatedclauses, listidx);
1848 :
1849 : /*
1850 : * Reset the pointers, so that choose_best_statistics knows this
1851 : * clause was estimated and does not consider it again.
1852 : */
1853 1152 : bms_free(list_attnums[listidx]);
1854 1152 : list_attnums[listidx] = NULL;
1855 :
1856 1152 : list_free(list_exprs[listidx]);
1857 1152 : list_exprs[listidx] = NULL;
1858 : }
1859 :
1860 480 : if (is_or)
1861 : {
1862 96 : bool *or_matches = NULL;
1863 96 : Selectivity simple_or_sel = 0.0,
1864 96 : stat_sel = 0.0;
1865 : MCVList *mcv_list;
1866 :
1867 : /* Load the MCV list stored in the statistics object */
1868 96 : mcv_list = statext_mcv_load(stat->statOid, rte->inh);
1869 :
1870 : /*
1871 : * Compute the selectivity of the ORed list of clauses covered by
1872 : * this statistics object by estimating each in turn and combining
1873 : * them using the formula P(A OR B) = P(A) + P(B) - P(A AND B).
1874 : * This allows us to use the multivariate MCV stats to better
1875 : * estimate the individual terms and their overlap.
1876 : *
1877 : * Each time we iterate this formula, the clause "A" above is
1878 : * equal to all the clauses processed so far, combined with "OR".
1879 : */
1880 96 : listidx = 0;
1881 336 : foreach(l, stat_clauses)
1882 : {
1883 240 : Node *clause = (Node *) lfirst(l);
1884 : Selectivity simple_sel,
1885 : overlap_simple_sel,
1886 : mcv_sel,
1887 : mcv_basesel,
1888 : overlap_mcvsel,
1889 : overlap_basesel,
1890 : mcv_totalsel,
1891 : clause_sel,
1892 : overlap_sel;
1893 :
1894 : /*
1895 : * "Simple" selectivity of the next clause and its overlap
1896 : * with any of the previous clauses. These are our initial
1897 : * estimates of P(B) and P(A AND B), assuming independence of
1898 : * columns/clauses.
1899 : */
1900 240 : simple_sel = clause_selectivity_ext(root, clause, varRelid,
1901 : jointype, sjinfo, false);
1902 :
1903 240 : overlap_simple_sel = simple_or_sel * simple_sel;
1904 :
1905 : /*
1906 : * New "simple" selectivity of all clauses seen so far,
1907 : * assuming independence.
1908 : */
1909 240 : simple_or_sel += simple_sel - overlap_simple_sel;
1910 240 : CLAMP_PROBABILITY(simple_or_sel);
1911 :
1912 : /*
1913 : * Multi-column estimate of this clause using MCV statistics,
1914 : * along with base and total selectivities, and corresponding
1915 : * selectivities for the overlap term P(A AND B).
1916 : */
1917 240 : mcv_sel = mcv_clause_selectivity_or(root, stat, mcv_list,
1918 : clause, &or_matches,
1919 : &mcv_basesel,
1920 : &overlap_mcvsel,
1921 : &overlap_basesel,
1922 : &mcv_totalsel);
1923 :
1924 : /*
1925 : * Combine the simple and multi-column estimates.
1926 : *
1927 : * If this clause is a simple single-column clause, then we
1928 : * just use the simple selectivity estimate for it, since the
1929 : * multi-column statistics are unlikely to improve on that
1930 : * (and in fact could make it worse). For the overlap, we
1931 : * always make use of the multi-column statistics.
1932 : */
1933 240 : if (bms_is_member(listidx, simple_clauses))
1934 192 : clause_sel = simple_sel;
1935 : else
1936 48 : clause_sel = mcv_combine_selectivities(simple_sel,
1937 : mcv_sel,
1938 : mcv_basesel,
1939 : mcv_totalsel);
1940 :
1941 240 : overlap_sel = mcv_combine_selectivities(overlap_simple_sel,
1942 : overlap_mcvsel,
1943 : overlap_basesel,
1944 : mcv_totalsel);
1945 :
1946 : /* Factor these into the result for this statistics object */
1947 240 : stat_sel += clause_sel - overlap_sel;
1948 240 : CLAMP_PROBABILITY(stat_sel);
1949 :
1950 240 : listidx++;
1951 : }
1952 :
1953 : /*
1954 : * Factor the result for this statistics object into the overall
1955 : * result. We treat the results from each separate statistics
1956 : * object as independent of one another.
1957 : */
1958 96 : sel = sel + stat_sel - sel * stat_sel;
1959 : }
1960 : else /* Implicitly-ANDed list of clauses */
1961 : {
1962 : Selectivity simple_sel,
1963 : mcv_sel,
1964 : mcv_basesel,
1965 : mcv_totalsel,
1966 : stat_sel;
1967 :
1968 : /*
1969 : * "Simple" selectivity, i.e. without any extended statistics,
1970 : * essentially assuming independence of the columns/clauses.
1971 : */
1972 384 : simple_sel = clauselist_selectivity_ext(root, stat_clauses,
1973 : varRelid, jointype,
1974 : sjinfo, false);
1975 :
1976 : /*
1977 : * Multi-column estimate using MCV statistics, along with base and
1978 : * total selectivities.
1979 : */
1980 384 : mcv_sel = mcv_clauselist_selectivity(root, stat, stat_clauses,
1981 : varRelid, jointype, sjinfo,
1982 : rel, &mcv_basesel,
1983 : &mcv_totalsel);
1984 :
1985 : /* Combine the simple and multi-column estimates. */
1986 384 : stat_sel = mcv_combine_selectivities(simple_sel,
1987 : mcv_sel,
1988 : mcv_basesel,
1989 : mcv_totalsel);
1990 :
1991 : /* Factor this into the overall result */
1992 384 : sel *= stat_sel;
1993 : }
1994 : }
1995 :
1996 498 : return sel;
1997 : }
1998 :
1999 : /*
2000 : * statext_clauselist_selectivity
2001 : * Estimate clauses using the best multi-column statistics.
2002 : */
2003 : Selectivity
2004 1842 : statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
2005 : JoinType jointype, SpecialJoinInfo *sjinfo,
2006 : RelOptInfo *rel, Bitmapset **estimatedclauses,
2007 : bool is_or)
2008 : {
2009 : Selectivity sel;
2010 :
2011 : /* First, try estimating clauses using a multivariate MCV list. */
2012 1842 : sel = statext_mcv_clauselist_selectivity(root, clauses, varRelid, jointype,
2013 : sjinfo, rel, estimatedclauses, is_or);
2014 :
2015 : /*
2016 : * Functional dependencies only work for clauses connected by AND, so for
2017 : * OR clauses we're done.
2018 : */
2019 1842 : if (is_or)
2020 108 : return sel;
2021 :
2022 : /*
2023 : * Then, apply functional dependencies on the remaining clauses by calling
2024 : * dependencies_clauselist_selectivity. Pass 'estimatedclauses' so the
2025 : * function can properly skip clauses already estimated above.
2026 : *
2027 : * The reasoning for applying dependencies last is that the more complex
2028 : * stats can track more complex correlations between the attributes, and
2029 : * so may be considered more reliable.
2030 : *
2031 : * For example, MCV list can give us an exact selectivity for values in
2032 : * two columns, while functional dependencies can only provide information
2033 : * about the overall strength of the dependency.
2034 : */
2035 1734 : sel *= dependencies_clauselist_selectivity(root, clauses, varRelid,
2036 : jointype, sjinfo, rel,
2037 : estimatedclauses);
2038 :
2039 1734 : return sel;
2040 : }
2041 :
2042 : /*
2043 : * examine_opclause_args
2044 : * Split an operator expression's arguments into Expr and Const parts.
2045 : *
2046 : * Attempts to match the arguments to either (Expr op Const) or (Const op
2047 : * Expr), possibly with a RelabelType on top. When the expression matches this
2048 : * form, returns true, otherwise returns false.
2049 : *
2050 : * Optionally returns pointers to the extracted Expr/Const nodes, when passed
2051 : * non-null pointers (exprp, cstp and expronleftp). The expronleftp flag
2052 : * specifies on which side of the operator we found the expression node.
2053 : */
2054 : bool
2055 2232 : examine_opclause_args(List *args, Node **exprp, Const **cstp,
2056 : bool *expronleftp)
2057 : {
2058 : Node *expr;
2059 : Const *cst;
2060 : bool expronleft;
2061 : Node *leftop,
2062 : *rightop;
2063 :
2064 : /* enforced by statext_is_compatible_clause_internal */
2065 : Assert(list_length(args) == 2);
2066 :
2067 2232 : leftop = linitial(args);
2068 2232 : rightop = lsecond(args);
2069 :
2070 : /* strip RelabelType from either side of the expression */
2071 2232 : if (IsA(leftop, RelabelType))
2072 324 : leftop = (Node *) ((RelabelType *) leftop)->arg;
2073 :
2074 2232 : if (IsA(rightop, RelabelType))
2075 60 : rightop = (Node *) ((RelabelType *) rightop)->arg;
2076 :
2077 2232 : if (IsA(rightop, Const))
2078 : {
2079 2070 : expr = (Node *) leftop;
2080 2070 : cst = (Const *) rightop;
2081 2070 : expronleft = true;
2082 : }
2083 162 : else if (IsA(leftop, Const))
2084 : {
2085 162 : expr = (Node *) rightop;
2086 162 : cst = (Const *) leftop;
2087 162 : expronleft = false;
2088 : }
2089 : else
2090 0 : return false;
2091 :
2092 : /* return pointers to the extracted parts if requested */
2093 2232 : if (exprp)
2094 2232 : *exprp = expr;
2095 :
2096 2232 : if (cstp)
2097 1080 : *cstp = cst;
2098 :
2099 2232 : if (expronleftp)
2100 1296 : *expronleftp = expronleft;
2101 :
2102 2232 : return true;
2103 : }
2104 :
2105 :
2106 : /*
2107 : * Compute statistics about expressions of a relation.
2108 : */
2109 : static void
2110 150 : compute_expr_stats(Relation onerel, double totalrows,
2111 : AnlExprData *exprdata, int nexprs,
2112 : HeapTuple *rows, int numrows)
2113 : {
2114 : MemoryContext expr_context,
2115 : old_context;
2116 : int ind,
2117 : i;
2118 :
2119 150 : expr_context = AllocSetContextCreate(CurrentMemoryContext,
2120 : "Analyze Expression",
2121 : ALLOCSET_DEFAULT_SIZES);
2122 150 : old_context = MemoryContextSwitchTo(expr_context);
2123 :
2124 438 : for (ind = 0; ind < nexprs; ind++)
2125 : {
2126 288 : AnlExprData *thisdata = &exprdata[ind];
2127 288 : VacAttrStats *stats = thisdata->vacattrstat;
2128 288 : Node *expr = thisdata->expr;
2129 : TupleTableSlot *slot;
2130 : EState *estate;
2131 : ExprContext *econtext;
2132 : Datum *exprvals;
2133 : bool *exprnulls;
2134 : ExprState *exprstate;
2135 : int tcnt;
2136 :
2137 : /* Are we still in the main context? */
2138 : Assert(CurrentMemoryContext == expr_context);
2139 :
2140 : /*
2141 : * Need an EState for evaluation of expressions. Create it in the
2142 : * per-expression context to be sure it gets cleaned up at the bottom
2143 : * of the loop.
2144 : */
2145 288 : estate = CreateExecutorState();
2146 288 : econtext = GetPerTupleExprContext(estate);
2147 :
2148 : /* Set up expression evaluation state */
2149 288 : exprstate = ExecPrepareExpr((Expr *) expr, estate);
2150 :
2151 : /* Need a slot to hold the current heap tuple, too */
2152 288 : slot = MakeSingleTupleTableSlot(RelationGetDescr(onerel),
2153 : &TTSOpsHeapTuple);
2154 :
2155 : /* Arrange for econtext's scan tuple to be the tuple under test */
2156 288 : econtext->ecxt_scantuple = slot;
2157 :
2158 : /* Compute and save expression values */
2159 288 : exprvals = (Datum *) palloc(numrows * sizeof(Datum));
2160 288 : exprnulls = (bool *) palloc(numrows * sizeof(bool));
2161 :
2162 288 : tcnt = 0;
2163 399882 : for (i = 0; i < numrows; i++)
2164 : {
2165 : Datum datum;
2166 : bool isnull;
2167 :
2168 : /*
2169 : * Reset the per-tuple context each time, to reclaim any cruft
2170 : * left behind by evaluating the statistics expressions.
2171 : */
2172 399594 : ResetExprContext(econtext);
2173 :
2174 : /* Set up for expression evaluation */
2175 399594 : ExecStoreHeapTuple(rows[i], slot, false);
2176 :
2177 : /*
2178 : * Evaluate the expression. We do this in the per-tuple context so
2179 : * as not to leak memory, and then copy the result into the
2180 : * context created at the beginning of this function.
2181 : */
2182 399594 : datum = ExecEvalExprSwitchContext(exprstate,
2183 399594 : GetPerTupleExprContext(estate),
2184 : &isnull);
2185 399594 : if (isnull)
2186 : {
2187 0 : exprvals[tcnt] = (Datum) 0;
2188 0 : exprnulls[tcnt] = true;
2189 : }
2190 : else
2191 : {
2192 : /* Make sure we copy the data into the context. */
2193 : Assert(CurrentMemoryContext == expr_context);
2194 :
2195 799188 : exprvals[tcnt] = datumCopy(datum,
2196 399594 : stats->attrtype->typbyval,
2197 399594 : stats->attrtype->typlen);
2198 399594 : exprnulls[tcnt] = false;
2199 : }
2200 :
2201 399594 : tcnt++;
2202 : }
2203 :
2204 : /*
2205 : * Now we can compute the statistics for the expression columns.
2206 : *
2207 : * XXX Unlike compute_index_stats we don't need to switch and reset
2208 : * memory contexts here, because we're only computing stats for a
2209 : * single expression (and not iterating over many indexes), so we just
2210 : * do it in expr_context. Note that compute_stats copies the result
2211 : * into stats->anl_context, so it does not disappear.
2212 : */
2213 288 : if (tcnt > 0)
2214 : {
2215 : AttributeOpts *aopt =
2216 288 : get_attribute_options(onerel->rd_id, stats->tupattnum);
2217 :
2218 288 : stats->exprvals = exprvals;
2219 288 : stats->exprnulls = exprnulls;
2220 288 : stats->rowstride = 1;
2221 288 : stats->compute_stats(stats,
2222 : expr_fetch_func,
2223 : tcnt,
2224 : tcnt);
2225 :
2226 : /*
2227 : * If the n_distinct option is specified, it overrides the above
2228 : * computation.
2229 : */
2230 288 : if (aopt != NULL && aopt->n_distinct != 0.0)
2231 0 : stats->stadistinct = aopt->n_distinct;
2232 : }
2233 :
2234 : /* And clean up */
2235 288 : MemoryContextSwitchTo(expr_context);
2236 :
2237 288 : ExecDropSingleTupleTableSlot(slot);
2238 288 : FreeExecutorState(estate);
2239 288 : MemoryContextReset(expr_context);
2240 : }
2241 :
2242 150 : MemoryContextSwitchTo(old_context);
2243 150 : MemoryContextDelete(expr_context);
2244 150 : }
2245 :
2246 :
2247 : /*
2248 : * Fetch function for analyzing statistics object expressions.
2249 : *
2250 : * We have not bothered to construct tuples from the data, instead the data
2251 : * is just in Datum arrays.
2252 : */
2253 : static Datum
2254 399594 : expr_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull)
2255 : {
2256 : int i;
2257 :
2258 : /* exprvals and exprnulls are already offset for proper column */
2259 399594 : i = rownum * stats->rowstride;
2260 399594 : *isNull = stats->exprnulls[i];
2261 399594 : return stats->exprvals[i];
2262 : }
2263 :
2264 : /*
2265 : * Build analyze data for a list of expressions. As this is not tied
2266 : * directly to a relation (table or index), we have to fake some of
2267 : * the fields in examine_expression().
2268 : */
2269 : static AnlExprData *
2270 150 : build_expr_data(List *exprs, int stattarget)
2271 : {
2272 : int idx;
2273 150 : int nexprs = list_length(exprs);
2274 : AnlExprData *exprdata;
2275 : ListCell *lc;
2276 :
2277 150 : exprdata = (AnlExprData *) palloc0(nexprs * sizeof(AnlExprData));
2278 :
2279 150 : idx = 0;
2280 438 : foreach(lc, exprs)
2281 : {
2282 288 : Node *expr = (Node *) lfirst(lc);
2283 288 : AnlExprData *thisdata = &exprdata[idx];
2284 :
2285 288 : thisdata->expr = expr;
2286 288 : thisdata->vacattrstat = examine_expression(expr, stattarget);
2287 288 : idx++;
2288 : }
2289 :
2290 150 : return exprdata;
2291 : }
2292 :
2293 : /* form an array of pg_statistic rows (per update_attstats) */
2294 : static Datum
2295 150 : serialize_expr_stats(AnlExprData *exprdata, int nexprs)
2296 : {
2297 : int exprno;
2298 : Oid typOid;
2299 : Relation sd;
2300 :
2301 150 : ArrayBuildState *astate = NULL;
2302 :
2303 150 : sd = table_open(StatisticRelationId, RowExclusiveLock);
2304 :
2305 : /* lookup OID of composite type for pg_statistic */
2306 150 : typOid = get_rel_type_id(StatisticRelationId);
2307 150 : if (!OidIsValid(typOid))
2308 0 : ereport(ERROR,
2309 : (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2310 : errmsg("relation \"%s\" does not have a composite type",
2311 : "pg_statistic")));
2312 :
2313 438 : for (exprno = 0; exprno < nexprs; exprno++)
2314 : {
2315 : int i,
2316 : k;
2317 288 : VacAttrStats *stats = exprdata[exprno].vacattrstat;
2318 :
2319 : Datum values[Natts_pg_statistic];
2320 : bool nulls[Natts_pg_statistic];
2321 : HeapTuple stup;
2322 :
2323 288 : if (!stats->stats_valid)
2324 : {
2325 0 : astate = accumArrayResult(astate,
2326 : (Datum) 0,
2327 : true,
2328 : typOid,
2329 : CurrentMemoryContext);
2330 0 : continue;
2331 : }
2332 :
2333 : /*
2334 : * Construct a new pg_statistic tuple
2335 : */
2336 9216 : for (i = 0; i < Natts_pg_statistic; ++i)
2337 : {
2338 8928 : nulls[i] = false;
2339 : }
2340 :
2341 288 : values[Anum_pg_statistic_starelid - 1] = ObjectIdGetDatum(InvalidOid);
2342 288 : values[Anum_pg_statistic_staattnum - 1] = Int16GetDatum(InvalidAttrNumber);
2343 288 : values[Anum_pg_statistic_stainherit - 1] = BoolGetDatum(false);
2344 288 : values[Anum_pg_statistic_stanullfrac - 1] = Float4GetDatum(stats->stanullfrac);
2345 288 : values[Anum_pg_statistic_stawidth - 1] = Int32GetDatum(stats->stawidth);
2346 288 : values[Anum_pg_statistic_stadistinct - 1] = Float4GetDatum(stats->stadistinct);
2347 288 : i = Anum_pg_statistic_stakind1 - 1;
2348 1728 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2349 : {
2350 1440 : values[i++] = Int16GetDatum(stats->stakind[k]); /* stakindN */
2351 : }
2352 288 : i = Anum_pg_statistic_staop1 - 1;
2353 1728 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2354 : {
2355 1440 : values[i++] = ObjectIdGetDatum(stats->staop[k]); /* staopN */
2356 : }
2357 288 : i = Anum_pg_statistic_stacoll1 - 1;
2358 1728 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2359 : {
2360 1440 : values[i++] = ObjectIdGetDatum(stats->stacoll[k]); /* stacollN */
2361 : }
2362 288 : i = Anum_pg_statistic_stanumbers1 - 1;
2363 1728 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2364 : {
2365 1440 : int nnum = stats->numnumbers[k];
2366 :
2367 1440 : if (nnum > 0)
2368 : {
2369 : int n;
2370 564 : Datum *numdatums = (Datum *) palloc(nnum * sizeof(Datum));
2371 : ArrayType *arry;
2372 :
2373 4938 : for (n = 0; n < nnum; n++)
2374 4374 : numdatums[n] = Float4GetDatum(stats->stanumbers[k][n]);
2375 564 : arry = construct_array_builtin(numdatums, nnum, FLOAT4OID);
2376 564 : values[i++] = PointerGetDatum(arry); /* stanumbersN */
2377 : }
2378 : else
2379 : {
2380 876 : nulls[i] = true;
2381 876 : values[i++] = (Datum) 0;
2382 : }
2383 : }
2384 288 : i = Anum_pg_statistic_stavalues1 - 1;
2385 1728 : for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
2386 : {
2387 1440 : if (stats->numvalues[k] > 0)
2388 : {
2389 : ArrayType *arry;
2390 :
2391 306 : arry = construct_array(stats->stavalues[k],
2392 : stats->numvalues[k],
2393 : stats->statypid[k],
2394 306 : stats->statyplen[k],
2395 306 : stats->statypbyval[k],
2396 306 : stats->statypalign[k]);
2397 306 : values[i++] = PointerGetDatum(arry); /* stavaluesN */
2398 : }
2399 : else
2400 : {
2401 1134 : nulls[i] = true;
2402 1134 : values[i++] = (Datum) 0;
2403 : }
2404 : }
2405 :
2406 288 : stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
2407 :
2408 288 : astate = accumArrayResult(astate,
2409 : heap_copy_tuple_as_datum(stup, RelationGetDescr(sd)),
2410 : false,
2411 : typOid,
2412 : CurrentMemoryContext);
2413 : }
2414 :
2415 150 : table_close(sd, RowExclusiveLock);
2416 :
2417 150 : return makeArrayResult(astate, CurrentMemoryContext);
2418 : }
2419 :
2420 : /*
2421 : * Loads pg_statistic record from expression statistics for expression
2422 : * identified by the supplied index.
2423 : */
2424 : HeapTuple
2425 1644 : statext_expressions_load(Oid stxoid, bool inh, int idx)
2426 : {
2427 : bool isnull;
2428 : Datum value;
2429 : HeapTuple htup;
2430 : ExpandedArrayHeader *eah;
2431 : HeapTupleHeader td;
2432 : HeapTupleData tmptup;
2433 : HeapTuple tup;
2434 :
2435 1644 : htup = SearchSysCache2(STATEXTDATASTXOID,
2436 : ObjectIdGetDatum(stxoid), BoolGetDatum(inh));
2437 1644 : if (!HeapTupleIsValid(htup))
2438 0 : elog(ERROR, "cache lookup failed for statistics object %u", stxoid);
2439 :
2440 1644 : value = SysCacheGetAttr(STATEXTDATASTXOID, htup,
2441 : Anum_pg_statistic_ext_data_stxdexpr, &isnull);
2442 1644 : if (isnull)
2443 0 : elog(ERROR,
2444 : "requested statistics kind \"%c\" is not yet built for statistics object %u",
2445 : STATS_EXT_EXPRESSIONS, stxoid);
2446 :
2447 1644 : eah = DatumGetExpandedArray(value);
2448 :
2449 1644 : deconstruct_expanded_array(eah);
2450 :
2451 1644 : td = DatumGetHeapTupleHeader(eah->dvalues[idx]);
2452 :
2453 : /* Build a temporary HeapTuple control structure */
2454 1644 : tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
2455 1644 : ItemPointerSetInvalid(&(tmptup.t_self));
2456 1644 : tmptup.t_tableOid = InvalidOid;
2457 1644 : tmptup.t_data = td;
2458 :
2459 1644 : tup = heap_copytuple(&tmptup);
2460 :
2461 1644 : ReleaseSysCache(htup);
2462 :
2463 1644 : return tup;
2464 : }
2465 :
2466 : /*
2467 : * Evaluate the expressions, so that we can use the results to build
2468 : * all the requested statistics types. This matters especially for
2469 : * expensive expressions, of course.
2470 : */
2471 : static StatsBuildData *
2472 348 : make_build_data(Relation rel, StatExtEntry *stat, int numrows, HeapTuple *rows,
2473 : VacAttrStats **stats, int stattarget)
2474 : {
2475 : /* evaluated expressions */
2476 : StatsBuildData *result;
2477 : char *ptr;
2478 : Size len;
2479 :
2480 : int i;
2481 : int k;
2482 : int idx;
2483 : TupleTableSlot *slot;
2484 : EState *estate;
2485 : ExprContext *econtext;
2486 348 : List *exprstates = NIL;
2487 348 : int nkeys = bms_num_members(stat->columns) + list_length(stat->exprs);
2488 : ListCell *lc;
2489 :
2490 : /* allocate everything as a single chunk, so we can free it easily */
2491 348 : len = MAXALIGN(sizeof(StatsBuildData));
2492 348 : len += MAXALIGN(sizeof(AttrNumber) * nkeys); /* attnums */
2493 348 : len += MAXALIGN(sizeof(VacAttrStats *) * nkeys); /* stats */
2494 :
2495 : /* values */
2496 348 : len += MAXALIGN(sizeof(Datum *) * nkeys);
2497 348 : len += nkeys * MAXALIGN(sizeof(Datum) * numrows);
2498 :
2499 : /* nulls */
2500 348 : len += MAXALIGN(sizeof(bool *) * nkeys);
2501 348 : len += nkeys * MAXALIGN(sizeof(bool) * numrows);
2502 :
2503 348 : ptr = palloc(len);
2504 :
2505 : /* set the pointers */
2506 348 : result = (StatsBuildData *) ptr;
2507 348 : ptr += MAXALIGN(sizeof(StatsBuildData));
2508 :
2509 : /* attnums */
2510 348 : result->attnums = (AttrNumber *) ptr;
2511 348 : ptr += MAXALIGN(sizeof(AttrNumber) * nkeys);
2512 :
2513 : /* stats */
2514 348 : result->stats = (VacAttrStats **) ptr;
2515 348 : ptr += MAXALIGN(sizeof(VacAttrStats *) * nkeys);
2516 :
2517 : /* values */
2518 348 : result->values = (Datum **) ptr;
2519 348 : ptr += MAXALIGN(sizeof(Datum *) * nkeys);
2520 :
2521 : /* nulls */
2522 348 : result->nulls = (bool **) ptr;
2523 348 : ptr += MAXALIGN(sizeof(bool *) * nkeys);
2524 :
2525 1248 : for (i = 0; i < nkeys; i++)
2526 : {
2527 900 : result->values[i] = (Datum *) ptr;
2528 900 : ptr += MAXALIGN(sizeof(Datum) * numrows);
2529 :
2530 900 : result->nulls[i] = (bool *) ptr;
2531 900 : ptr += MAXALIGN(sizeof(bool) * numrows);
2532 : }
2533 :
2534 : Assert((ptr - (char *) result) == len);
2535 :
2536 : /* we have it allocated, so let's fill the values */
2537 348 : result->nattnums = nkeys;
2538 348 : result->numrows = numrows;
2539 :
2540 : /* fill the attribute info - first attributes, then expressions */
2541 348 : idx = 0;
2542 348 : k = -1;
2543 960 : while ((k = bms_next_member(stat->columns, k)) >= 0)
2544 : {
2545 612 : result->attnums[idx] = k;
2546 612 : result->stats[idx] = stats[idx];
2547 :
2548 612 : idx++;
2549 : }
2550 :
2551 348 : k = -1;
2552 636 : foreach(lc, stat->exprs)
2553 : {
2554 288 : Node *expr = (Node *) lfirst(lc);
2555 :
2556 288 : result->attnums[idx] = k;
2557 288 : result->stats[idx] = examine_expression(expr, stattarget);
2558 :
2559 288 : idx++;
2560 288 : k--;
2561 : }
2562 :
2563 : /* first extract values for all the regular attributes */
2564 738966 : for (i = 0; i < numrows; i++)
2565 : {
2566 738618 : idx = 0;
2567 738618 : k = -1;
2568 2432454 : while ((k = bms_next_member(stat->columns, k)) >= 0)
2569 : {
2570 3387672 : result->values[idx][i] = heap_getattr(rows[i], k,
2571 1693836 : result->stats[idx]->tupDesc,
2572 1693836 : &result->nulls[idx][i]);
2573 :
2574 1693836 : idx++;
2575 : }
2576 : }
2577 :
2578 : /* Need an EState for evaluation expressions. */
2579 348 : estate = CreateExecutorState();
2580 348 : econtext = GetPerTupleExprContext(estate);
2581 :
2582 : /* Need a slot to hold the current heap tuple, too */
2583 348 : slot = MakeSingleTupleTableSlot(RelationGetDescr(rel),
2584 : &TTSOpsHeapTuple);
2585 :
2586 : /* Arrange for econtext's scan tuple to be the tuple under test */
2587 348 : econtext->ecxt_scantuple = slot;
2588 :
2589 : /* Set up expression evaluation state */
2590 348 : exprstates = ExecPrepareExprList(stat->exprs, estate);
2591 :
2592 738966 : for (i = 0; i < numrows; i++)
2593 : {
2594 : /*
2595 : * Reset the per-tuple context each time, to reclaim any cruft left
2596 : * behind by evaluating the statistics object expressions.
2597 : */
2598 738618 : ResetExprContext(econtext);
2599 :
2600 : /* Set up for expression evaluation */
2601 738618 : ExecStoreHeapTuple(rows[i], slot, false);
2602 :
2603 738618 : idx = bms_num_members(stat->columns);
2604 1138212 : foreach(lc, exprstates)
2605 : {
2606 : Datum datum;
2607 : bool isnull;
2608 399594 : ExprState *exprstate = (ExprState *) lfirst(lc);
2609 :
2610 : /*
2611 : * XXX This probably leaks memory. Maybe we should use
2612 : * ExecEvalExprSwitchContext but then we need to copy the result
2613 : * somewhere else.
2614 : */
2615 399594 : datum = ExecEvalExpr(exprstate,
2616 399594 : GetPerTupleExprContext(estate),
2617 : &isnull);
2618 399594 : if (isnull)
2619 : {
2620 0 : result->values[idx][i] = (Datum) 0;
2621 0 : result->nulls[idx][i] = true;
2622 : }
2623 : else
2624 : {
2625 399594 : result->values[idx][i] = (Datum) datum;
2626 399594 : result->nulls[idx][i] = false;
2627 : }
2628 :
2629 399594 : idx++;
2630 : }
2631 : }
2632 :
2633 348 : ExecDropSingleTupleTableSlot(slot);
2634 348 : FreeExecutorState(estate);
2635 :
2636 348 : return result;
2637 : }
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