Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * planagg.c
4 : : * Special planning for aggregate queries.
5 : : *
6 : : * This module tries to replace MIN/MAX aggregate functions by subqueries
7 : : * of the form
8 : : * (SELECT col FROM tab
9 : : * WHERE col IS NOT NULL AND existing-quals
10 : : * ORDER BY col ASC/DESC
11 : : * LIMIT 1)
12 : : * Given a suitable index on tab.col, this can be much faster than the
13 : : * generic scan-all-the-rows aggregation plan. We can handle multiple
14 : : * MIN/MAX aggregates by generating multiple subqueries, and their
15 : : * orderings can be different. However, if the query contains any
16 : : * non-optimizable aggregates, there's no point since we'll have to
17 : : * scan all the rows anyway.
18 : : *
19 : : *
20 : : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
21 : : * Portions Copyright (c) 1994, Regents of the University of California
22 : : *
23 : : *
24 : : * IDENTIFICATION
25 : : * src/backend/optimizer/plan/planagg.c
26 : : *
27 : : *-------------------------------------------------------------------------
28 : : */
29 : : #include "postgres.h"
30 : :
31 : : #include "access/htup_details.h"
32 : : #include "catalog/pg_aggregate.h"
33 : : #include "catalog/pg_type.h"
34 : : #include "nodes/makefuncs.h"
35 : : #include "nodes/nodeFuncs.h"
36 : : #include "optimizer/cost.h"
37 : : #include "optimizer/optimizer.h"
38 : : #include "optimizer/pathnode.h"
39 : : #include "optimizer/paths.h"
40 : : #include "optimizer/planmain.h"
41 : : #include "optimizer/subselect.h"
42 : : #include "optimizer/tlist.h"
43 : : #include "parser/parse_clause.h"
44 : : #include "parser/parsetree.h"
45 : : #include "rewrite/rewriteManip.h"
46 : : #include "utils/lsyscache.h"
47 : : #include "utils/syscache.h"
48 : :
49 : : static bool can_minmax_aggs(PlannerInfo *root, List **context);
50 : : static bool build_minmax_path(PlannerInfo *root, MinMaxAggInfo *mminfo,
51 : : Oid eqop, Oid sortop, bool reverse_sort,
52 : : bool nulls_first);
53 : : static void minmax_qp_callback(PlannerInfo *root, void *extra);
54 : : static Oid fetch_agg_sort_op(Oid aggfnoid);
55 : :
56 : :
57 : : /*
58 : : * preprocess_minmax_aggregates - preprocess MIN/MAX aggregates
59 : : *
60 : : * Check to see whether the query contains MIN/MAX aggregate functions that
61 : : * might be optimizable via indexscans. If it does, and all the aggregates
62 : : * are potentially optimizable, then create a MinMaxAggPath and add it to
63 : : * the (UPPERREL_GROUP_AGG, NULL) upperrel.
64 : : *
65 : : * This should be called by grouping_planner() just before it's ready to call
66 : : * query_planner(), because we generate indexscan paths by cloning the
67 : : * planner's state and invoking query_planner() on a modified version of
68 : : * the query parsetree. Thus, all preprocessing needed before query_planner()
69 : : * must already be done. This relies on the list of aggregates in
70 : : * root->agginfos, so preprocess_aggrefs() must have been called already, too.
71 : : */
72 : : void
2355 tgl@sss.pgh.pa.us 73 :CBC 18108 : preprocess_minmax_aggregates(PlannerInfo *root)
74 : : {
7398 75 : 18108 : Query *parse = root->parse;
76 : : FromExpr *jtnode;
77 : : RangeTblRef *rtr;
78 : : RangeTblEntry *rte;
79 : : List *aggs_list;
80 : : RelOptInfo *grouped_rel;
81 : : ListCell *lc;
82 : :
83 : : /* minmax_aggs list should be empty at this point */
5420 84 [ - + ]: 18108 : Assert(root->minmax_aggs == NIL);
85 : :
86 : : /* Nothing to do if query has no aggregates */
7398 87 [ - + ]: 18108 : if (!parse->hasAggs)
5420 88 : 17903 : return;
89 : :
2999 90 [ - + ]: 18108 : Assert(!parse->setOperations); /* shouldn't get here if a setop */
91 [ - + ]: 18108 : Assert(parse->rowMarks == NIL); /* nor if FOR UPDATE */
92 : :
93 : : /*
94 : : * Reject unoptimizable cases.
95 : : *
96 : : * We don't handle GROUP BY or windowing, because our current
97 : : * implementations of grouping require looking at all the rows anyway, and
98 : : * so there's not much point in optimizing MIN/MAX.
99 : : */
3470 100 [ + + + + ]: 18108 : if (parse->groupClause || list_length(parse->groupingSets) > 1 ||
101 [ + + ]: 16194 : parse->hasWindowFuncs)
5420 102 : 1917 : return;
103 : :
104 : : /*
105 : : * Reject if query contains any CTEs; there's no way to build an indexscan
106 : : * on one so we couldn't succeed here. (If the CTEs are unreferenced,
107 : : * that's not true, but it doesn't seem worth expending cycles to check.)
108 : : */
3189 109 [ + + ]: 16191 : if (parse->cteList)
110 : 37 : return;
111 : :
112 : : /*
113 : : * We also restrict the query to reference exactly one table, since join
114 : : * conditions can't be handled reasonably. (We could perhaps handle a
115 : : * query containing cartesian-product joins, but it hardly seems worth the
116 : : * trouble.) However, the single table could be buried in several levels
117 : : * of FromExpr due to subqueries. Note the "single" table could be an
118 : : * inheritance parent, too, including the case of a UNION ALL subquery
119 : : * that's been flattened to an appendrel.
120 : : */
6787 121 : 16154 : jtnode = parse->jointree;
122 [ + + ]: 30493 : while (IsA(jtnode, FromExpr))
123 : : {
124 [ + + ]: 16171 : if (list_length(jtnode->fromlist) != 1)
5420 125 : 1832 : return;
6787 126 : 14339 : jtnode = linitial(jtnode->fromlist);
127 : : }
128 [ + + ]: 14322 : if (!IsA(jtnode, RangeTblRef))
5420 129 : 660 : return;
6787 130 : 13662 : rtr = (RangeTblRef *) jtnode;
6713 131 [ - + ]: 13662 : rte = planner_rt_fetch(rtr->rtindex, root);
4922 132 [ + + ]: 13662 : if (rte->rtekind == RTE_RELATION)
133 : : /* ordinary relation, ok */ ;
134 [ + + + + ]: 1845 : else if (rte->rtekind == RTE_SUBQUERY && rte->inh)
135 : : /* flattened UNION ALL subquery, ok */ ;
136 : : else
5420 137 : 1818 : return;
138 : :
139 : : /*
140 : : * Examine all the aggregates and verify all are MIN/MAX aggregates. Stop
141 : : * as soon as we find one that isn't.
142 : : */
7453 143 : 11844 : aggs_list = NIL;
1747 heikki.linnakangas@i 144 [ + + ]: 11844 : if (!can_minmax_aggs(root, &aggs_list))
5420 tgl@sss.pgh.pa.us 145 : 11484 : return;
146 : :
147 : : /*
148 : : * OK, there is at least the possibility of performing the optimization.
149 : : * Build an access path for each aggregate. If any of the aggregates
150 : : * prove to be non-indexable, give up; there is no point in optimizing
151 : : * just some of them.
152 : : */
153 [ + - + + : 583 : foreach(lc, aggs_list)
+ + ]
154 : : {
155 : 378 : MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
156 : : Oid eqop;
157 : : bool reverse;
158 : :
159 : : /*
160 : : * We'll need the equality operator that goes with the aggregate's
161 : : * ordering operator.
162 : : */
5282 163 : 378 : eqop = get_equality_op_for_ordering_op(mminfo->aggsortop, &reverse);
5263 bruce@momjian.us 164 [ - + ]: 378 : if (!OidIsValid(eqop)) /* shouldn't happen */
5282 tgl@sss.pgh.pa.us 165 [ # # ]:UBC 0 : elog(ERROR, "could not find equality operator for ordering operator %u",
166 : : mminfo->aggsortop);
167 : :
168 : : /*
169 : : * We can use either an ordering that gives NULLS FIRST or one that
170 : : * gives NULLS LAST; furthermore there's unlikely to be much
171 : : * performance difference between them, so it doesn't seem worth
172 : : * costing out both ways if we get a hit on the first one. NULLS
173 : : * FIRST is more likely to be available if the operator is a
174 : : * reverse-sort operator, so try that first if reverse.
175 : : */
327 peter@eisentraut.org 176 [ + + ]:CBC 378 : if (build_minmax_path(root, mminfo, eqop, mminfo->aggsortop, reverse, reverse))
5282 tgl@sss.pgh.pa.us 177 : 223 : continue;
327 peter@eisentraut.org 178 [ - + ]: 155 : if (build_minmax_path(root, mminfo, eqop, mminfo->aggsortop, reverse, !reverse))
5282 tgl@sss.pgh.pa.us 179 :UBC 0 : continue;
180 : :
181 : : /* No indexable path for this aggregate, so fail */
5282 tgl@sss.pgh.pa.us 182 :CBC 155 : return;
183 : : }
184 : :
185 : : /*
186 : : * OK, we can do the query this way. Prepare to create a MinMaxAggPath
187 : : * node.
188 : : *
189 : : * First, create an output Param node for each agg. (If we end up not
190 : : * using the MinMaxAggPath, we'll waste a PARAM_EXEC slot for each agg,
191 : : * which is not worth worrying about. We can't wait till create_plan time
192 : : * to decide whether to make the Param, unfortunately.)
193 : : */
3470 194 [ + - + + : 428 : foreach(lc, aggs_list)
+ + ]
195 : : {
5420 196 : 223 : MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
197 : :
3470 198 : 223 : mminfo->param =
199 : 223 : SS_make_initplan_output_param(root,
200 : 223 : exprType((Node *) mminfo->target),
201 : : -1,
2999 202 : 223 : exprCollation((Node *) mminfo->target));
203 : : }
204 : :
205 : : /*
206 : : * Create a MinMaxAggPath node with the appropriate estimated costs and
207 : : * other needed data, and add it to the UPPERREL_GROUP_AGG upperrel, where
208 : : * it will compete against the standard aggregate implementation. (It
209 : : * will likely always win, but we need not assume that here.)
210 : : *
211 : : * Note: grouping_planner won't have created this upperrel yet, but it's
212 : : * fine for us to create it first. We will not have inserted the correct
213 : : * consider_parallel value in it, but MinMaxAggPath paths are currently
214 : : * never parallel-safe anyway, so that doesn't matter. Likewise, it
215 : : * doesn't matter that we haven't filled FDW-related fields in the rel.
216 : : * Also, because there are no rowmarks, we know that the processed_tlist
217 : : * doesn't need to change anymore, so making the pathtarget now is safe.
218 : : */
3470 219 : 205 : grouped_rel = fetch_upper_rel(root, UPPERREL_GROUP_AGG, NULL);
220 : 205 : add_path(grouped_rel, (Path *)
221 : 205 : create_minmaxagg_path(root, grouped_rel,
222 : : create_pathtarget(root,
223 : : root->processed_tlist),
224 : : aggs_list,
225 : 205 : (List *) parse->havingQual));
226 : : }
227 : :
228 : : /*
229 : : * can_minmax_aggs
230 : : * Examine all the aggregates in the query, and check if they are
231 : : * all MIN/MAX aggregates. If so, build a list of MinMaxAggInfo
232 : : * nodes for them.
233 : : *
234 : : * Returns false if a non-MIN/MAX aggregate is found, true otherwise.
235 : : */
236 : : static bool
1747 heikki.linnakangas@i 237 : 11844 : can_minmax_aggs(PlannerInfo *root, List **context)
238 : : {
239 : : ListCell *lc;
240 : :
241 : : /*
242 : : * This function used to have to scan the query for itself, but now we can
243 : : * just thumb through the AggInfo list made by preprocess_aggrefs.
244 : : */
245 [ + - + + : 12384 : foreach(lc, root->agginfos)
+ + ]
246 : : {
1145 tgl@sss.pgh.pa.us 247 : 12024 : AggInfo *agginfo = lfirst_node(AggInfo, lc);
1131 drowley@postgresql.o 248 : 12024 : Aggref *aggref = linitial_node(Aggref, agginfo->aggrefs);
249 : : Oid aggsortop;
250 : : TargetEntry *curTarget;
251 : : MinMaxAggInfo *mminfo;
252 : :
7453 tgl@sss.pgh.pa.us 253 [ - + ]: 12024 : Assert(aggref->agglevelsup == 0);
4435 noah@leadboat.com 254 [ + + ]: 12024 : if (list_length(aggref->args) != 1)
1747 heikki.linnakangas@i 255 : 11484 : return false; /* it couldn't be MIN/MAX */
256 : :
257 : : /*
258 : : * ORDER BY is usually irrelevant for MIN/MAX, but it can change the
259 : : * outcome if the aggsortop's operator class recognizes non-identical
260 : : * values as equal. For example, 4.0 and 4.00 are equal according to
261 : : * numeric_ops, yet distinguishable. If MIN() receives more than one
262 : : * value equal to 4.0 and no value less than 4.0, it is unspecified
263 : : * which of those equal values MIN() returns. An ORDER BY expression
264 : : * that differs for each of those equal values of the argument
265 : : * expression makes the result predictable once again. This is a
266 : : * niche requirement, and we do not implement it with subquery paths.
267 : : * In any case, this test lets us reject ordered-set aggregates
268 : : * quickly.
269 : : */
4435 noah@leadboat.com 270 [ + + ]: 7286 : if (aggref->aggorder != NIL)
1747 heikki.linnakangas@i 271 : 262 : return false;
272 : : /* note: we do not care if DISTINCT is mentioned ... */
273 : :
274 : : /*
275 : : * We might implement the optimization when a FILTER clause is present
276 : : * by adding the filter to the quals of the generated subquery. For
277 : : * now, just punt.
278 : : */
4435 noah@leadboat.com 279 [ + + ]: 7024 : if (aggref->aggfilter != NULL)
1747 heikki.linnakangas@i 280 : 221 : return false;
281 : :
7453 tgl@sss.pgh.pa.us 282 : 6803 : aggsortop = fetch_agg_sort_op(aggref->aggfnoid);
283 [ + + ]: 6803 : if (!OidIsValid(aggsortop))
1747 heikki.linnakangas@i 284 : 6247 : return false; /* not a MIN/MAX aggregate */
285 : :
4435 noah@leadboat.com 286 : 556 : curTarget = (TargetEntry *) linitial(aggref->args);
287 : :
5420 tgl@sss.pgh.pa.us 288 [ + + ]: 556 : if (contain_mutable_functions((Node *) curTarget->expr))
1747 heikki.linnakangas@i 289 : 4 : return false; /* not potentially indexable */
290 : :
5420 tgl@sss.pgh.pa.us 291 [ + + ]: 552 : if (type_is_rowtype(exprType((Node *) curTarget->expr)))
1747 heikki.linnakangas@i 292 : 12 : return false; /* IS NOT NULL would have weird semantics */
293 : :
5420 tgl@sss.pgh.pa.us 294 : 540 : mminfo = makeNode(MinMaxAggInfo);
295 : 540 : mminfo->aggfnoid = aggref->aggfnoid;
296 : 540 : mminfo->aggsortop = aggsortop;
297 : 540 : mminfo->target = curTarget->expr;
5263 bruce@momjian.us 298 : 540 : mminfo->subroot = NULL; /* don't compute path yet */
5282 tgl@sss.pgh.pa.us 299 : 540 : mminfo->path = NULL;
300 : 540 : mminfo->pathcost = 0;
301 : 540 : mminfo->param = NULL;
302 : :
5420 303 : 540 : *context = lappend(*context, mminfo);
304 : : }
1747 heikki.linnakangas@i 305 : 360 : return true;
306 : : }
307 : :
308 : : /*
309 : : * build_minmax_path
310 : : * Given a MIN/MAX aggregate, try to build an indexscan Path it can be
311 : : * optimized with.
312 : : *
313 : : * If successful, stash the best path in *mminfo and return true.
314 : : * Otherwise, return false.
315 : : */
316 : : static bool
5282 tgl@sss.pgh.pa.us 317 : 533 : build_minmax_path(PlannerInfo *root, MinMaxAggInfo *mminfo,
318 : : Oid eqop, Oid sortop, bool reverse_sort, bool nulls_first)
319 : : {
320 : : PlannerInfo *subroot;
321 : : Query *parse;
322 : : TargetEntry *tle;
323 : : List *tlist;
324 : : NullTest *ntest;
325 : : SortGroupClause *sortcl;
326 : : RelOptInfo *final_rel;
327 : : Path *sorted_path;
328 : : Cost path_cost;
329 : : double path_fraction;
330 : :
331 : : /*
332 : : * We are going to construct what is effectively a sub-SELECT query, so
333 : : * clone the current query level's state and adjust it to make it look
334 : : * like a subquery. Any outer references will now be one level higher
335 : : * than before. (This means that when we are done, there will be no Vars
336 : : * of level 1, which is why the subquery can become an initplan.)
337 : : */
338 : 533 : subroot = (PlannerInfo *) palloc(sizeof(PlannerInfo));
339 : 533 : memcpy(subroot, root, sizeof(PlannerInfo));
3470 340 : 533 : subroot->query_level++;
341 : 533 : subroot->parent_root = root;
342 : : /* reset subplan-related stuff */
3679 343 : 533 : subroot->plan_params = NIL;
344 : 533 : subroot->outer_params = NULL;
345 : 533 : subroot->init_plans = NIL;
1747 heikki.linnakangas@i 346 : 533 : subroot->agginfos = NIL;
347 : 533 : subroot->aggtransinfos = NIL;
348 : :
3103 peter_e@gmx.net 349 : 533 : subroot->parse = parse = copyObject(root->parse);
3470 tgl@sss.pgh.pa.us 350 : 533 : IncrementVarSublevelsUp((Node *) parse, 1, 1);
351 : :
352 : : /* append_rel_list might contain outer Vars? */
3103 peter_e@gmx.net 353 : 533 : subroot->append_rel_list = copyObject(root->append_rel_list);
3470 tgl@sss.pgh.pa.us 354 : 533 : IncrementVarSublevelsUp((Node *) subroot->append_rel_list, 1, 1);
355 : : /* There shouldn't be any OJ info to translate, as yet */
5282 356 [ - + ]: 533 : Assert(subroot->join_info_list == NIL);
357 : : /* and we haven't made equivalence classes, either */
3470 358 [ - + ]: 533 : Assert(subroot->eq_classes == NIL);
359 : : /* and we haven't created PlaceHolderInfos, either */
5282 360 [ - + ]: 533 : Assert(subroot->placeholder_list == NIL);
361 : :
362 : : /*----------
363 : : * Generate modified query of the form
364 : : * (SELECT col FROM tab
365 : : * WHERE col IS NOT NULL AND existing-quals
366 : : * ORDER BY col ASC/DESC
367 : : * LIMIT 1)
368 : : *----------
369 : : */
370 : : /* single tlist entry that is the aggregate target */
371 : 533 : tle = makeTargetEntry(copyObject(mminfo->target),
372 : : (AttrNumber) 1,
373 : : pstrdup("agg_target"),
374 : : false);
3470 375 : 533 : tlist = list_make1(tle);
376 : 533 : subroot->processed_tlist = parse->targetList = tlist;
377 : :
378 : : /* No HAVING, no DISTINCT, no aggregates anymore */
5282 379 : 533 : parse->havingQual = NULL;
380 : 533 : subroot->hasHavingQual = false;
381 : 533 : parse->distinctClause = NIL;
382 : 533 : parse->hasDistinctOn = false;
383 : 533 : parse->hasAggs = false;
384 : :
385 : : /* Build "target IS NOT NULL" expression */
386 : 533 : ntest = makeNode(NullTest);
387 : 533 : ntest->nulltesttype = IS_NOT_NULL;
388 : 533 : ntest->arg = copyObject(mminfo->target);
389 : : /* we checked it wasn't a rowtype in can_minmax_aggs */
390 : 533 : ntest->argisrow = false;
3849 391 : 533 : ntest->location = -1;
392 : :
393 : : /* User might have had that in WHERE already */
5282 394 [ + - ]: 533 : if (!list_member((List *) parse->jointree->quals, ntest))
395 : 533 : parse->jointree->quals = (Node *)
396 : 533 : lcons(ntest, (List *) parse->jointree->quals);
397 : :
398 : : /* Build suitable ORDER BY clause */
399 : 533 : sortcl = makeNode(SortGroupClause);
2355 400 : 533 : sortcl->tleSortGroupRef = assignSortGroupRef(tle, subroot->processed_tlist);
5282 401 : 533 : sortcl->eqop = eqop;
402 : 533 : sortcl->sortop = sortop;
327 peter@eisentraut.org 403 : 533 : sortcl->reverse_sort = reverse_sort;
5282 tgl@sss.pgh.pa.us 404 : 533 : sortcl->nulls_first = nulls_first;
5263 bruce@momjian.us 405 : 533 : sortcl->hashable = false; /* no need to make this accurate */
5282 tgl@sss.pgh.pa.us 406 : 533 : parse->sortClause = list_make1(sortcl);
407 : :
408 : : /* set up expressions for LIMIT 1 */
409 : 533 : parse->limitOffset = NULL;
5279 410 : 533 : parse->limitCount = (Node *) makeConst(INT8OID, -1, InvalidOid,
411 : : sizeof(int64),
412 : : Int64GetDatum(1), false,
413 : : true);
414 : :
415 : : /*
416 : : * Generate the best paths for this query, telling query_planner that we
417 : : * have LIMIT 1.
418 : : */
4415 419 : 533 : subroot->tuple_fraction = 1.0;
420 : 533 : subroot->limit_tuples = 1.0;
421 : :
2355 422 : 533 : final_rel = query_planner(subroot, minmax_qp_callback, NULL);
423 : :
424 : : /*
425 : : * Since we didn't go through subquery_planner() to handle the subquery,
426 : : * we have to do some of the same cleanup it would do, in particular cope
427 : : * with params and initplans used within this subquery. (This won't
428 : : * matter if we end up not using the subplan.)
429 : : */
3470 430 : 533 : SS_identify_outer_params(subroot);
431 : 533 : SS_charge_for_initplans(subroot, final_rel);
432 : :
433 : : /*
434 : : * Get the best presorted path, that being the one that's cheapest for
435 : : * fetching just one row. If there's no such path, fail.
436 : : */
4415 437 [ + + ]: 533 : if (final_rel->rows > 1.0)
438 : 515 : path_fraction = 1.0 / final_rel->rows;
439 : : else
440 : 18 : path_fraction = 1.0;
441 : :
442 : : sorted_path =
443 : 533 : get_cheapest_fractional_path_for_pathkeys(final_rel->pathlist,
444 : : subroot->query_pathkeys,
445 : : NULL,
446 : : path_fraction);
5282 447 [ + + ]: 533 : if (!sorted_path)
4415 448 : 310 : return false;
449 : :
450 : : /*
451 : : * The path might not return exactly what we want, so fix that. (We
452 : : * assume that this won't change any conclusions about which was the
453 : : * cheapest path.)
454 : : */
3470 455 : 223 : sorted_path = apply_projection_to_path(subroot, final_rel, sorted_path,
456 : : create_pathtarget(subroot,
457 : : subroot->processed_tlist));
458 : :
459 : : /*
460 : : * Determine cost to get just the first row of the presorted path.
461 : : *
462 : : * Note: cost calculation here should match
463 : : * compare_fractional_path_costs().
464 : : */
5282 465 : 223 : path_cost = sorted_path->startup_cost +
466 : 223 : path_fraction * (sorted_path->total_cost - sorted_path->startup_cost);
467 : :
468 : : /* Save state for further processing */
469 : 223 : mminfo->subroot = subroot;
470 : 223 : mminfo->path = sorted_path;
471 : 223 : mminfo->pathcost = path_cost;
472 : :
473 : 223 : return true;
474 : : }
475 : :
476 : : /*
477 : : * Compute query_pathkeys and other pathkeys during query_planner()
478 : : */
479 : : static void
4513 480 : 533 : minmax_qp_callback(PlannerInfo *root, void *extra)
481 : : {
482 : 533 : root->group_pathkeys = NIL;
483 : 533 : root->window_pathkeys = NIL;
484 : 533 : root->distinct_pathkeys = NIL;
485 : :
486 : 533 : root->sort_pathkeys =
487 : 533 : make_pathkeys_for_sortclauses(root,
488 : 533 : root->parse->sortClause,
489 : 533 : root->parse->targetList);
490 : :
491 : 533 : root->query_pathkeys = root->sort_pathkeys;
492 : 533 : }
493 : :
494 : : /*
495 : : * Get the OID of the sort operator, if any, associated with an aggregate.
496 : : * Returns InvalidOid if there is no such operator.
497 : : */
498 : : static Oid
7453 499 : 6803 : fetch_agg_sort_op(Oid aggfnoid)
500 : : {
501 : : HeapTuple aggTuple;
502 : : Form_pg_aggregate aggform;
503 : : Oid aggsortop;
504 : :
505 : : /* fetch aggregate entry from pg_aggregate */
5683 rhaas@postgresql.org 506 : 6803 : aggTuple = SearchSysCache1(AGGFNOID, ObjectIdGetDatum(aggfnoid));
7453 tgl@sss.pgh.pa.us 507 [ - + ]: 6803 : if (!HeapTupleIsValid(aggTuple))
7453 tgl@sss.pgh.pa.us 508 :UBC 0 : return InvalidOid;
7453 tgl@sss.pgh.pa.us 509 :CBC 6803 : aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);
510 : 6803 : aggsortop = aggform->aggsortop;
511 : 6803 : ReleaseSysCache(aggTuple);
512 : :
513 : 6803 : return aggsortop;
514 : : }
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