Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * subselect.c
4 : * Planning routines for subselects.
5 : *
6 : * This module deals with SubLinks and CTEs, but not subquery RTEs (i.e.,
7 : * not sub-SELECT-in-FROM cases).
8 : *
9 : * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
10 : * Portions Copyright (c) 1994, Regents of the University of California
11 : *
12 : * IDENTIFICATION
13 : * src/backend/optimizer/plan/subselect.c
14 : *
15 : *-------------------------------------------------------------------------
16 : */
17 : #include "postgres.h"
18 :
19 : #include "access/htup_details.h"
20 : #include "catalog/pg_operator.h"
21 : #include "catalog/pg_type.h"
22 : #include "executor/executor.h"
23 : #include "miscadmin.h"
24 : #include "nodes/makefuncs.h"
25 : #include "nodes/nodeFuncs.h"
26 : #include "optimizer/clauses.h"
27 : #include "optimizer/cost.h"
28 : #include "optimizer/optimizer.h"
29 : #include "optimizer/paramassign.h"
30 : #include "optimizer/pathnode.h"
31 : #include "optimizer/planmain.h"
32 : #include "optimizer/planner.h"
33 : #include "optimizer/prep.h"
34 : #include "optimizer/subselect.h"
35 : #include "parser/parse_relation.h"
36 : #include "rewrite/rewriteManip.h"
37 : #include "utils/builtins.h"
38 : #include "utils/lsyscache.h"
39 : #include "utils/syscache.h"
40 :
41 :
42 : typedef struct convert_testexpr_context
43 : {
44 : PlannerInfo *root;
45 : List *subst_nodes; /* Nodes to substitute for Params */
46 : } convert_testexpr_context;
47 :
48 : typedef struct process_sublinks_context
49 : {
50 : PlannerInfo *root;
51 : bool isTopQual;
52 : } process_sublinks_context;
53 :
54 : typedef struct finalize_primnode_context
55 : {
56 : PlannerInfo *root;
57 : Bitmapset *paramids; /* Non-local PARAM_EXEC paramids found */
58 : } finalize_primnode_context;
59 :
60 : typedef struct inline_cte_walker_context
61 : {
62 : const char *ctename; /* name and relative level of target CTE */
63 : int levelsup;
64 : int refcount; /* number of remaining references */
65 : Query *ctequery; /* query to substitute */
66 : } inline_cte_walker_context;
67 :
68 :
69 : static Node *build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
70 : List *plan_params,
71 : SubLinkType subLinkType, int subLinkId,
72 : Node *testexpr, bool adjust_testexpr,
73 : bool unknownEqFalse);
74 : static List *generate_subquery_params(PlannerInfo *root, List *tlist,
75 : List **paramIds);
76 : static List *generate_subquery_vars(PlannerInfo *root, List *tlist,
77 : Index varno);
78 : static Node *convert_testexpr(PlannerInfo *root,
79 : Node *testexpr,
80 : List *subst_nodes);
81 : static Node *convert_testexpr_mutator(Node *node,
82 : convert_testexpr_context *context);
83 : static bool subplan_is_hashable(Plan *plan);
84 : static bool testexpr_is_hashable(Node *testexpr);
85 : static bool hash_ok_operator(OpExpr *expr);
86 : static bool contain_dml(Node *node);
87 : static bool contain_dml_walker(Node *node, void *context);
88 : static bool contain_outer_selfref(Node *node);
89 : static bool contain_outer_selfref_walker(Node *node, Index *depth);
90 : static void inline_cte(PlannerInfo *root, CommonTableExpr *cte);
91 : static bool inline_cte_walker(Node *node, inline_cte_walker_context *context);
92 : static bool simplify_EXISTS_query(PlannerInfo *root, Query *query);
93 : static Query *convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
94 : Node **testexpr, List **paramIds);
95 : static Node *replace_correlation_vars_mutator(Node *node, PlannerInfo *root);
96 : static Node *process_sublinks_mutator(Node *node,
97 : process_sublinks_context *context);
98 : static Bitmapset *finalize_plan(PlannerInfo *root,
99 : Plan *plan,
100 : int gather_param,
101 : Bitmapset *valid_params,
102 : Bitmapset *scan_params);
103 : static bool finalize_primnode(Node *node, finalize_primnode_context *context);
104 : static bool finalize_agg_primnode(Node *node, finalize_primnode_context *context);
105 :
106 :
107 : /*
108 : * Get the datatype/typmod/collation of the first column of the plan's output.
109 : *
110 : * This information is stored for ARRAY_SUBLINK execution and for
111 : * exprType()/exprTypmod()/exprCollation(), which have no way to get at the
112 : * plan associated with a SubPlan node. We really only need the info for
113 : * EXPR_SUBLINK and ARRAY_SUBLINK subplans, but for consistency we save it
114 : * always.
115 : */
116 : static void
117 46230 : get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod,
118 : Oid *colcollation)
119 : {
120 : /* In cases such as EXISTS, tlist might be empty; arbitrarily use VOID */
121 46230 : if (plan->targetlist)
122 : {
123 44478 : TargetEntry *tent = linitial_node(TargetEntry, plan->targetlist);
124 :
125 44478 : if (!tent->resjunk)
126 : {
127 44478 : *coltype = exprType((Node *) tent->expr);
128 44478 : *coltypmod = exprTypmod((Node *) tent->expr);
129 44478 : *colcollation = exprCollation((Node *) tent->expr);
130 44478 : return;
131 : }
132 : }
133 1752 : *coltype = VOIDOID;
134 1752 : *coltypmod = -1;
135 1752 : *colcollation = InvalidOid;
136 : }
137 :
138 : /*
139 : * Convert a SubLink (as created by the parser) into a SubPlan.
140 : *
141 : * We are given the SubLink's contained query, type, ID, and testexpr. We are
142 : * also told if this expression appears at top level of a WHERE/HAVING qual.
143 : *
144 : * Note: we assume that the testexpr has been AND/OR flattened (actually,
145 : * it's been through eval_const_expressions), but not converted to
146 : * implicit-AND form; and any SubLinks in it should already have been
147 : * converted to SubPlans. The subquery is as yet untouched, however.
148 : *
149 : * The result is whatever we need to substitute in place of the SubLink node
150 : * in the executable expression. If we're going to do the subplan as a
151 : * regular subplan, this will be the constructed SubPlan node. If we're going
152 : * to do the subplan as an InitPlan, the SubPlan node instead goes into
153 : * root->init_plans, and what we return here is an expression tree
154 : * representing the InitPlan's result: usually just a Param node representing
155 : * a single scalar result, but possibly a row comparison tree containing
156 : * multiple Param nodes, or for a MULTIEXPR subquery a simple NULL constant
157 : * (since the real output Params are elsewhere in the tree, and the MULTIEXPR
158 : * subquery itself is in a resjunk tlist entry whose value is uninteresting).
159 : */
160 : static Node *
161 44072 : make_subplan(PlannerInfo *root, Query *orig_subquery,
162 : SubLinkType subLinkType, int subLinkId,
163 : Node *testexpr, bool isTopQual)
164 : {
165 : Query *subquery;
166 44072 : bool simple_exists = false;
167 : double tuple_fraction;
168 : PlannerInfo *subroot;
169 : RelOptInfo *final_rel;
170 : Path *best_path;
171 : Plan *plan;
172 : List *plan_params;
173 : Node *result;
174 :
175 : /*
176 : * Copy the source Query node. This is a quick and dirty kluge to resolve
177 : * the fact that the parser can generate trees with multiple links to the
178 : * same sub-Query node, but the planner wants to scribble on the Query.
179 : * Try to clean this up when we do querytree redesign...
180 : */
181 44072 : subquery = copyObject(orig_subquery);
182 :
183 : /*
184 : * If it's an EXISTS subplan, we might be able to simplify it.
185 : */
186 44072 : if (subLinkType == EXISTS_SUBLINK)
187 1600 : simple_exists = simplify_EXISTS_query(root, subquery);
188 :
189 : /*
190 : * For an EXISTS subplan, tell lower-level planner to expect that only the
191 : * first tuple will be retrieved. For ALL and ANY subplans, we will be
192 : * able to stop evaluating if the test condition fails or matches, so very
193 : * often not all the tuples will be retrieved; for lack of a better idea,
194 : * specify 50% retrieval. For EXPR, MULTIEXPR, and ROWCOMPARE subplans,
195 : * use default behavior (we're only expecting one row out, anyway).
196 : *
197 : * NOTE: if you change these numbers, also change cost_subplan() in
198 : * path/costsize.c.
199 : *
200 : * XXX If an ANY subplan is uncorrelated, build_subplan may decide to hash
201 : * its output. In that case it would've been better to specify full
202 : * retrieval. At present, however, we can only check hashability after
203 : * we've made the subplan :-(. (Determining whether it'll fit in work_mem
204 : * is the really hard part.) Therefore, we don't want to be too
205 : * optimistic about the percentage of tuples retrieved, for fear of
206 : * selecting a plan that's bad for the materialization case.
207 : */
208 44072 : if (subLinkType == EXISTS_SUBLINK)
209 1600 : tuple_fraction = 1.0; /* just like a LIMIT 1 */
210 42472 : else if (subLinkType == ALL_SUBLINK ||
211 : subLinkType == ANY_SUBLINK)
212 198 : tuple_fraction = 0.5; /* 50% */
213 : else
214 42274 : tuple_fraction = 0.0; /* default behavior */
215 :
216 : /* plan_params should not be in use in current query level */
217 : Assert(root->plan_params == NIL);
218 :
219 : /* Generate Paths for the subquery */
220 44072 : subroot = subquery_planner(root->glob, subquery,
221 : root,
222 : false, tuple_fraction);
223 :
224 : /* Isolate the params needed by this specific subplan */
225 44072 : plan_params = root->plan_params;
226 44072 : root->plan_params = NIL;
227 :
228 : /*
229 : * Select best Path and turn it into a Plan. At least for now, there
230 : * seems no reason to postpone doing that.
231 : */
232 44072 : final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
233 44072 : best_path = get_cheapest_fractional_path(final_rel, tuple_fraction);
234 :
235 44072 : plan = create_plan(subroot, best_path);
236 :
237 : /* And convert to SubPlan or InitPlan format. */
238 44072 : result = build_subplan(root, plan, subroot, plan_params,
239 : subLinkType, subLinkId,
240 : testexpr, true, isTopQual);
241 :
242 : /*
243 : * If it's a correlated EXISTS with an unimportant targetlist, we might be
244 : * able to transform it to the equivalent of an IN and then implement it
245 : * by hashing. We don't have enough information yet to tell which way is
246 : * likely to be better (it depends on the expected number of executions of
247 : * the EXISTS qual, and we are much too early in planning the outer query
248 : * to be able to guess that). So we generate both plans, if possible, and
249 : * leave it to the executor to decide which to use.
250 : */
251 44072 : if (simple_exists && IsA(result, SubPlan))
252 : {
253 : Node *newtestexpr;
254 : List *paramIds;
255 :
256 : /* Make a second copy of the original subquery */
257 1424 : subquery = copyObject(orig_subquery);
258 : /* and re-simplify */
259 1424 : simple_exists = simplify_EXISTS_query(root, subquery);
260 : Assert(simple_exists);
261 : /* See if it can be converted to an ANY query */
262 1424 : subquery = convert_EXISTS_to_ANY(root, subquery,
263 : &newtestexpr, ¶mIds);
264 1424 : if (subquery)
265 : {
266 : /* Generate Paths for the ANY subquery; we'll need all rows */
267 1110 : subroot = subquery_planner(root->glob, subquery,
268 : root,
269 : false, 0.0);
270 :
271 : /* Isolate the params needed by this specific subplan */
272 1110 : plan_params = root->plan_params;
273 1110 : root->plan_params = NIL;
274 :
275 : /* Select best Path and turn it into a Plan */
276 1110 : final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
277 1110 : best_path = final_rel->cheapest_total_path;
278 :
279 1110 : plan = create_plan(subroot, best_path);
280 :
281 : /* Now we can check if it'll fit in work_mem */
282 : /* XXX can we check this at the Path stage? */
283 1110 : if (subplan_is_hashable(plan))
284 : {
285 : SubPlan *hashplan;
286 : AlternativeSubPlan *asplan;
287 :
288 : /* OK, convert to SubPlan format. */
289 1110 : hashplan = castNode(SubPlan,
290 : build_subplan(root, plan, subroot,
291 : plan_params,
292 : ANY_SUBLINK, 0,
293 : newtestexpr,
294 : false, true));
295 : /* Check we got what we expected */
296 : Assert(hashplan->parParam == NIL);
297 : Assert(hashplan->useHashTable);
298 : /* build_subplan won't have filled in paramIds */
299 1110 : hashplan->paramIds = paramIds;
300 :
301 : /* Leave it to the executor to decide which plan to use */
302 1110 : asplan = makeNode(AlternativeSubPlan);
303 1110 : asplan->subplans = list_make2(result, hashplan);
304 1110 : result = (Node *) asplan;
305 : }
306 : }
307 : }
308 :
309 44072 : return result;
310 : }
311 :
312 : /*
313 : * Build a SubPlan node given the raw inputs --- subroutine for make_subplan
314 : *
315 : * Returns either the SubPlan, or a replacement expression if we decide to
316 : * make it an InitPlan, as explained in the comments for make_subplan.
317 : */
318 : static Node *
319 45182 : build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
320 : List *plan_params,
321 : SubLinkType subLinkType, int subLinkId,
322 : Node *testexpr, bool adjust_testexpr,
323 : bool unknownEqFalse)
324 : {
325 : Node *result;
326 : SubPlan *splan;
327 : bool isInitPlan;
328 : ListCell *lc;
329 :
330 : /*
331 : * Initialize the SubPlan node. Note plan_id, plan_name, and cost fields
332 : * are set further down.
333 : */
334 45182 : splan = makeNode(SubPlan);
335 45182 : splan->subLinkType = subLinkType;
336 45182 : splan->testexpr = NULL;
337 45182 : splan->paramIds = NIL;
338 45182 : get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
339 : &splan->firstColCollation);
340 45182 : splan->useHashTable = false;
341 45182 : splan->unknownEqFalse = unknownEqFalse;
342 45182 : splan->parallel_safe = plan->parallel_safe;
343 45182 : splan->setParam = NIL;
344 45182 : splan->parParam = NIL;
345 45182 : splan->args = NIL;
346 :
347 : /*
348 : * Make parParam and args lists of param IDs and expressions that current
349 : * query level will pass to this child plan.
350 : */
351 97972 : foreach(lc, plan_params)
352 : {
353 52790 : PlannerParamItem *pitem = (PlannerParamItem *) lfirst(lc);
354 52790 : Node *arg = pitem->item;
355 :
356 : /*
357 : * The Var, PlaceHolderVar, or Aggref has already been adjusted to
358 : * have the correct varlevelsup, phlevelsup, or agglevelsup.
359 : *
360 : * If it's a PlaceHolderVar or Aggref, its arguments might contain
361 : * SubLinks, which have not yet been processed (see the comments for
362 : * SS_replace_correlation_vars). Do that now.
363 : */
364 105572 : if (IsA(arg, PlaceHolderVar) ||
365 52782 : IsA(arg, Aggref))
366 40 : arg = SS_process_sublinks(root, arg, false);
367 :
368 52790 : splan->parParam = lappend_int(splan->parParam, pitem->paramId);
369 52790 : splan->args = lappend(splan->args, arg);
370 : }
371 :
372 : /*
373 : * Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY,
374 : * ROWCOMPARE, or MULTIEXPR types can be used as initPlans. For EXISTS,
375 : * EXPR, or ARRAY, we return a Param referring to the result of evaluating
376 : * the initPlan. For ROWCOMPARE, we must modify the testexpr tree to
377 : * contain PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted
378 : * by the parser, and then return that tree. For MULTIEXPR, we return a
379 : * null constant: the resjunk targetlist item containing the SubLink does
380 : * not need to return anything useful, since the referencing Params are
381 : * elsewhere.
382 : */
383 45182 : if (splan->parParam == NIL && subLinkType == EXISTS_SUBLINK)
384 158 : {
385 : Param *prm;
386 :
387 : Assert(testexpr == NULL);
388 158 : prm = generate_new_exec_param(root, BOOLOID, -1, InvalidOid);
389 158 : splan->setParam = list_make1_int(prm->paramid);
390 158 : isInitPlan = true;
391 158 : result = (Node *) prm;
392 : }
393 45024 : else if (splan->parParam == NIL && subLinkType == EXPR_SUBLINK)
394 8434 : {
395 8434 : TargetEntry *te = linitial(plan->targetlist);
396 : Param *prm;
397 :
398 : Assert(!te->resjunk);
399 : Assert(testexpr == NULL);
400 25302 : prm = generate_new_exec_param(root,
401 8434 : exprType((Node *) te->expr),
402 8434 : exprTypmod((Node *) te->expr),
403 8434 : exprCollation((Node *) te->expr));
404 8434 : splan->setParam = list_make1_int(prm->paramid);
405 8434 : isInitPlan = true;
406 8434 : result = (Node *) prm;
407 : }
408 36590 : else if (splan->parParam == NIL && subLinkType == ARRAY_SUBLINK)
409 58 : {
410 58 : TargetEntry *te = linitial(plan->targetlist);
411 : Oid arraytype;
412 : Param *prm;
413 :
414 : Assert(!te->resjunk);
415 : Assert(testexpr == NULL);
416 58 : arraytype = get_promoted_array_type(exprType((Node *) te->expr));
417 58 : if (!OidIsValid(arraytype))
418 0 : elog(ERROR, "could not find array type for datatype %s",
419 : format_type_be(exprType((Node *) te->expr)));
420 116 : prm = generate_new_exec_param(root,
421 : arraytype,
422 58 : exprTypmod((Node *) te->expr),
423 58 : exprCollation((Node *) te->expr));
424 58 : splan->setParam = list_make1_int(prm->paramid);
425 58 : isInitPlan = true;
426 58 : result = (Node *) prm;
427 : }
428 36532 : else if (splan->parParam == NIL && subLinkType == ROWCOMPARE_SUBLINK)
429 0 : {
430 : /* Adjust the Params */
431 : List *params;
432 :
433 : Assert(testexpr != NULL);
434 0 : params = generate_subquery_params(root,
435 : plan->targetlist,
436 : &splan->paramIds);
437 0 : result = convert_testexpr(root,
438 : testexpr,
439 : params);
440 0 : splan->setParam = list_copy(splan->paramIds);
441 0 : isInitPlan = true;
442 :
443 : /*
444 : * The executable expression is returned to become part of the outer
445 : * plan's expression tree; it is not kept in the initplan node.
446 : */
447 : }
448 36532 : else if (subLinkType == MULTIEXPR_SUBLINK)
449 : {
450 : /*
451 : * Whether it's an initplan or not, it needs to set a PARAM_EXEC Param
452 : * for each output column.
453 : */
454 : List *params;
455 :
456 : Assert(testexpr == NULL);
457 52 : params = generate_subquery_params(root,
458 : plan->targetlist,
459 : &splan->setParam);
460 :
461 : /*
462 : * Save the list of replacement Params in the n'th cell of
463 : * root->multiexpr_params; setrefs.c will use it to replace
464 : * PARAM_MULTIEXPR Params.
465 : */
466 156 : while (list_length(root->multiexpr_params) < subLinkId)
467 52 : root->multiexpr_params = lappend(root->multiexpr_params, NIL);
468 52 : lc = list_nth_cell(root->multiexpr_params, subLinkId - 1);
469 : Assert(lfirst(lc) == NIL);
470 52 : lfirst(lc) = params;
471 :
472 : /* It can be an initplan if there are no parParams. */
473 52 : if (splan->parParam == NIL)
474 : {
475 16 : isInitPlan = true;
476 16 : result = (Node *) makeNullConst(RECORDOID, -1, InvalidOid);
477 : }
478 : else
479 : {
480 36 : isInitPlan = false;
481 36 : result = (Node *) splan;
482 : }
483 : }
484 : else
485 : {
486 : /*
487 : * Adjust the Params in the testexpr, unless caller said it's not
488 : * needed.
489 : */
490 36480 : if (testexpr && adjust_testexpr)
491 198 : {
492 : List *params;
493 :
494 198 : params = generate_subquery_params(root,
495 : plan->targetlist,
496 : &splan->paramIds);
497 198 : splan->testexpr = convert_testexpr(root,
498 : testexpr,
499 : params);
500 : }
501 : else
502 36282 : splan->testexpr = testexpr;
503 :
504 : /*
505 : * We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
506 : * initPlans, even when they are uncorrelated or undirect correlated,
507 : * because we need to scan the output of the subplan for each outer
508 : * tuple. But if it's a not-direct-correlated IN (= ANY) test, we
509 : * might be able to use a hashtable to avoid comparing all the tuples.
510 : */
511 37776 : if (subLinkType == ANY_SUBLINK &&
512 2544 : splan->parParam == NIL &&
513 2496 : subplan_is_hashable(plan) &&
514 1248 : testexpr_is_hashable(splan->testexpr))
515 1248 : splan->useHashTable = true;
516 :
517 : /*
518 : * Otherwise, we have the option to tack a Material node onto the top
519 : * of the subplan, to reduce the cost of reading it repeatedly. This
520 : * is pointless for a direct-correlated subplan, since we'd have to
521 : * recompute its results each time anyway. For uncorrelated/undirect
522 : * correlated subplans, we add Material unless the subplan's top plan
523 : * node would materialize its output anyway. Also, if enable_material
524 : * is false, then the user does not want us to materialize anything
525 : * unnecessarily, so we don't.
526 : */
527 35244 : else if (splan->parParam == NIL && enable_material &&
528 12 : !ExecMaterializesOutput(nodeTag(plan)))
529 12 : plan = materialize_finished_plan(plan);
530 :
531 36480 : result = (Node *) splan;
532 36480 : isInitPlan = false;
533 : }
534 :
535 : /*
536 : * Add the subplan and its PlannerInfo to the global lists.
537 : */
538 45182 : root->glob->subplans = lappend(root->glob->subplans, plan);
539 45182 : root->glob->subroots = lappend(root->glob->subroots, subroot);
540 45182 : splan->plan_id = list_length(root->glob->subplans);
541 :
542 45182 : if (isInitPlan)
543 8666 : root->init_plans = lappend(root->init_plans, splan);
544 :
545 : /*
546 : * A parameterless subplan (not initplan) should be prepared to handle
547 : * REWIND efficiently. If it has direct parameters then there's no point
548 : * since it'll be reset on each scan anyway; and if it's an initplan then
549 : * there's no point since it won't get re-run without parameter changes
550 : * anyway. The input of a hashed subplan doesn't need REWIND either.
551 : */
552 45182 : if (splan->parParam == NIL && !isInitPlan && !splan->useHashTable)
553 12 : root->glob->rewindPlanIDs = bms_add_member(root->glob->rewindPlanIDs,
554 : splan->plan_id);
555 :
556 : /* Label the subplan for EXPLAIN purposes */
557 45182 : splan->plan_name = palloc(32 + 12 * list_length(splan->setParam));
558 45182 : sprintf(splan->plan_name, "%s %d",
559 : isInitPlan ? "InitPlan" : "SubPlan",
560 : splan->plan_id);
561 45182 : if (splan->setParam)
562 : {
563 8702 : char *ptr = splan->plan_name + strlen(splan->plan_name);
564 :
565 8702 : ptr += sprintf(ptr, " (returns ");
566 17456 : foreach(lc, splan->setParam)
567 : {
568 8754 : ptr += sprintf(ptr, "$%d%s",
569 : lfirst_int(lc),
570 8754 : lnext(splan->setParam, lc) ? "," : ")");
571 : }
572 : }
573 :
574 : /* Lastly, fill in the cost estimates for use later */
575 45182 : cost_subplan(root, splan, plan);
576 :
577 45182 : return result;
578 : }
579 :
580 : /*
581 : * generate_subquery_params: build a list of Params representing the output
582 : * columns of a sublink's sub-select, given the sub-select's targetlist.
583 : *
584 : * We also return an integer list of the paramids of the Params.
585 : */
586 : static List *
587 250 : generate_subquery_params(PlannerInfo *root, List *tlist, List **paramIds)
588 : {
589 : List *result;
590 : List *ids;
591 : ListCell *lc;
592 :
593 250 : result = ids = NIL;
594 588 : foreach(lc, tlist)
595 : {
596 338 : TargetEntry *tent = (TargetEntry *) lfirst(lc);
597 : Param *param;
598 :
599 338 : if (tent->resjunk)
600 4 : continue;
601 :
602 1002 : param = generate_new_exec_param(root,
603 334 : exprType((Node *) tent->expr),
604 334 : exprTypmod((Node *) tent->expr),
605 334 : exprCollation((Node *) tent->expr));
606 334 : result = lappend(result, param);
607 334 : ids = lappend_int(ids, param->paramid);
608 : }
609 :
610 250 : *paramIds = ids;
611 250 : return result;
612 : }
613 :
614 : /*
615 : * generate_subquery_vars: build a list of Vars representing the output
616 : * columns of a sublink's sub-select, given the sub-select's targetlist.
617 : * The Vars have the specified varno (RTE index).
618 : */
619 : static List *
620 560 : generate_subquery_vars(PlannerInfo *root, List *tlist, Index varno)
621 : {
622 : List *result;
623 : ListCell *lc;
624 :
625 560 : result = NIL;
626 1148 : foreach(lc, tlist)
627 : {
628 588 : TargetEntry *tent = (TargetEntry *) lfirst(lc);
629 : Var *var;
630 :
631 588 : if (tent->resjunk)
632 0 : continue;
633 :
634 588 : var = makeVarFromTargetEntry(varno, tent);
635 588 : result = lappend(result, var);
636 : }
637 :
638 560 : return result;
639 : }
640 :
641 : /*
642 : * convert_testexpr: convert the testexpr given by the parser into
643 : * actually executable form. This entails replacing PARAM_SUBLINK Params
644 : * with Params or Vars representing the results of the sub-select. The
645 : * nodes to be substituted are passed in as the List result from
646 : * generate_subquery_params or generate_subquery_vars.
647 : */
648 : static Node *
649 758 : convert_testexpr(PlannerInfo *root,
650 : Node *testexpr,
651 : List *subst_nodes)
652 : {
653 : convert_testexpr_context context;
654 :
655 758 : context.root = root;
656 758 : context.subst_nodes = subst_nodes;
657 758 : return convert_testexpr_mutator(testexpr, &context);
658 : }
659 :
660 : static Node *
661 3800 : convert_testexpr_mutator(Node *node,
662 : convert_testexpr_context *context)
663 : {
664 3800 : if (node == NULL)
665 12 : return NULL;
666 3788 : if (IsA(node, Param))
667 : {
668 818 : Param *param = (Param *) node;
669 :
670 818 : if (param->paramkind == PARAM_SUBLINK)
671 : {
672 1636 : if (param->paramid <= 0 ||
673 818 : param->paramid > list_length(context->subst_nodes))
674 0 : elog(ERROR, "unexpected PARAM_SUBLINK ID: %d", param->paramid);
675 :
676 : /*
677 : * We copy the list item to avoid having doubly-linked
678 : * substructure in the modified parse tree. This is probably
679 : * unnecessary when it's a Param, but be safe.
680 : */
681 818 : return (Node *) copyObject(list_nth(context->subst_nodes,
682 : param->paramid - 1));
683 : }
684 : }
685 2970 : if (IsA(node, SubLink))
686 : {
687 : /*
688 : * If we come across a nested SubLink, it is neither necessary nor
689 : * correct to recurse into it: any PARAM_SUBLINKs we might find inside
690 : * belong to the inner SubLink not the outer. So just return it as-is.
691 : *
692 : * This reasoning depends on the assumption that nothing will pull
693 : * subexpressions into or out of the testexpr field of a SubLink, at
694 : * least not without replacing PARAM_SUBLINKs first. If we did want
695 : * to do that we'd need to rethink the parser-output representation
696 : * altogether, since currently PARAM_SUBLINKs are only unique per
697 : * SubLink not globally across the query. The whole point of
698 : * replacing them with Vars or PARAM_EXEC nodes is to make them
699 : * globally unique before they escape from the SubLink's testexpr.
700 : *
701 : * Note: this can't happen when called during SS_process_sublinks,
702 : * because that recursively processes inner SubLinks first. It can
703 : * happen when called from convert_ANY_sublink_to_join, though.
704 : */
705 8 : return node;
706 : }
707 2962 : return expression_tree_mutator(node,
708 : convert_testexpr_mutator,
709 : (void *) context);
710 : }
711 :
712 : /*
713 : * subplan_is_hashable: can we implement an ANY subplan by hashing?
714 : */
715 : static bool
716 2358 : subplan_is_hashable(Plan *plan)
717 : {
718 : double subquery_size;
719 :
720 : /*
721 : * The estimated size of the subquery result must fit in work_mem. (Note:
722 : * we use heap tuple overhead here even though the tuples will actually be
723 : * stored as MinimalTuples; this provides some fudge factor for hashtable
724 : * overhead.)
725 : */
726 4716 : subquery_size = plan->plan_rows *
727 2358 : (MAXALIGN(plan->plan_width) + MAXALIGN(SizeofHeapTupleHeader));
728 2358 : if (subquery_size > work_mem * 1024L)
729 0 : return false;
730 :
731 2358 : return true;
732 : }
733 :
734 : /*
735 : * testexpr_is_hashable: is an ANY SubLink's test expression hashable?
736 : */
737 : static bool
738 1248 : testexpr_is_hashable(Node *testexpr)
739 : {
740 : /*
741 : * The testexpr must be a single OpExpr, or an AND-clause containing only
742 : * OpExprs.
743 : *
744 : * The combining operators must be hashable and strict. The need for
745 : * hashability is obvious, since we want to use hashing. Without
746 : * strictness, behavior in the presence of nulls is too unpredictable. We
747 : * actually must assume even more than plain strictness: they can't yield
748 : * NULL for non-null inputs, either (see nodeSubplan.c). However, hash
749 : * indexes and hash joins assume that too.
750 : */
751 1248 : if (testexpr && IsA(testexpr, OpExpr))
752 : {
753 752 : if (hash_ok_operator((OpExpr *) testexpr))
754 752 : return true;
755 : }
756 496 : else if (is_andclause(testexpr))
757 : {
758 : ListCell *l;
759 :
760 1488 : foreach(l, ((BoolExpr *) testexpr)->args)
761 : {
762 992 : Node *andarg = (Node *) lfirst(l);
763 :
764 992 : if (!IsA(andarg, OpExpr))
765 0 : return false;
766 992 : if (!hash_ok_operator((OpExpr *) andarg))
767 0 : return false;
768 : }
769 496 : return true;
770 : }
771 :
772 0 : return false;
773 : }
774 :
775 : /*
776 : * Check expression is hashable + strict
777 : *
778 : * We could use op_hashjoinable() and op_strict(), but do it like this to
779 : * avoid a redundant cache lookup.
780 : */
781 : static bool
782 5964 : hash_ok_operator(OpExpr *expr)
783 : {
784 5964 : Oid opid = expr->opno;
785 :
786 : /* quick out if not a binary operator */
787 5964 : if (list_length(expr->args) != 2)
788 0 : return false;
789 5964 : if (opid == ARRAY_EQ_OP)
790 : {
791 : /* array_eq is strict, but must check input type to ensure hashable */
792 : /* XXX record_eq will need same treatment when it becomes hashable */
793 0 : Node *leftarg = linitial(expr->args);
794 :
795 0 : return op_hashjoinable(opid, exprType(leftarg));
796 : }
797 : else
798 : {
799 : /* else must look up the operator properties */
800 : HeapTuple tup;
801 : Form_pg_operator optup;
802 :
803 5964 : tup = SearchSysCache1(OPEROID, ObjectIdGetDatum(opid));
804 5964 : if (!HeapTupleIsValid(tup))
805 0 : elog(ERROR, "cache lookup failed for operator %u", opid);
806 5964 : optup = (Form_pg_operator) GETSTRUCT(tup);
807 5964 : if (!optup->oprcanhash || !func_strict(optup->oprcode))
808 : {
809 316 : ReleaseSysCache(tup);
810 316 : return false;
811 : }
812 5648 : ReleaseSysCache(tup);
813 5648 : return true;
814 : }
815 : }
816 :
817 :
818 : /*
819 : * SS_process_ctes: process a query's WITH list
820 : *
821 : * Consider each CTE in the WITH list and either ignore it (if it's an
822 : * unreferenced SELECT), "inline" it to create a regular sub-SELECT-in-FROM,
823 : * or convert it to an initplan.
824 : *
825 : * A side effect is to fill in root->cte_plan_ids with a list that
826 : * parallels root->parse->cteList and provides the subplan ID for
827 : * each CTE's initplan, or a dummy ID (-1) if we didn't make an initplan.
828 : */
829 : void
830 1170 : SS_process_ctes(PlannerInfo *root)
831 : {
832 : ListCell *lc;
833 :
834 : Assert(root->cte_plan_ids == NIL);
835 :
836 2508 : foreach(lc, root->parse->cteList)
837 : {
838 1338 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
839 1338 : CmdType cmdType = ((Query *) cte->ctequery)->commandType;
840 : Query *subquery;
841 : PlannerInfo *subroot;
842 : RelOptInfo *final_rel;
843 : Path *best_path;
844 : Plan *plan;
845 : SubPlan *splan;
846 : int paramid;
847 :
848 : /*
849 : * Ignore SELECT CTEs that are not actually referenced anywhere.
850 : */
851 1338 : if (cte->cterefcount == 0 && cmdType == CMD_SELECT)
852 : {
853 : /* Make a dummy entry in cte_plan_ids */
854 8 : root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
855 8 : continue;
856 : }
857 :
858 : /*
859 : * Consider inlining the CTE (creating RTE_SUBQUERY RTE(s)) instead of
860 : * implementing it as a separately-planned CTE.
861 : *
862 : * We cannot inline if any of these conditions hold:
863 : *
864 : * 1. The user said not to (the CTEMaterializeAlways option).
865 : *
866 : * 2. The CTE is recursive.
867 : *
868 : * 3. The CTE has side-effects; this includes either not being a plain
869 : * SELECT, or containing volatile functions. Inlining might change
870 : * the side-effects, which would be bad.
871 : *
872 : * 4. The CTE is multiply-referenced and contains a self-reference to
873 : * a recursive CTE outside itself. Inlining would result in multiple
874 : * recursive self-references, which we don't support.
875 : *
876 : * Otherwise, we have an option whether to inline or not. That should
877 : * always be a win if there's just a single reference, but if the CTE
878 : * is multiply-referenced then it's unclear: inlining adds duplicate
879 : * computations, but the ability to absorb restrictions from the outer
880 : * query level could outweigh that. We do not have nearly enough
881 : * information at this point to tell whether that's true, so we let
882 : * the user express a preference. Our default behavior is to inline
883 : * only singly-referenced CTEs, but a CTE marked CTEMaterializeNever
884 : * will be inlined even if multiply referenced.
885 : *
886 : * Note: we check for volatile functions last, because that's more
887 : * expensive than the other tests needed.
888 : */
889 2640 : if ((cte->ctematerialized == CTEMaterializeNever ||
890 2552 : (cte->ctematerialized == CTEMaterializeDefault &&
891 2340 : cte->cterefcount == 1)) &&
892 1900 : !cte->cterecursive &&
893 660 : cmdType == CMD_SELECT &&
894 1314 : !contain_dml(cte->ctequery) &&
895 666 : (cte->cterefcount <= 1 ||
896 658 : !contain_outer_selfref(cte->ctequery)) &&
897 646 : !contain_volatile_functions(cte->ctequery))
898 : {
899 642 : inline_cte(root, cte);
900 : /* Make a dummy entry in cte_plan_ids */
901 642 : root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
902 642 : continue;
903 : }
904 :
905 : /*
906 : * Copy the source Query node. Probably not necessary, but let's keep
907 : * this similar to make_subplan.
908 : */
909 688 : subquery = (Query *) copyObject(cte->ctequery);
910 :
911 : /* plan_params should not be in use in current query level */
912 : Assert(root->plan_params == NIL);
913 :
914 : /*
915 : * Generate Paths for the CTE query. Always plan for full retrieval
916 : * --- we don't have enough info to predict otherwise.
917 : */
918 688 : subroot = subquery_planner(root->glob, subquery,
919 : root,
920 688 : cte->cterecursive, 0.0);
921 :
922 : /*
923 : * Since the current query level doesn't yet contain any RTEs, it
924 : * should not be possible for the CTE to have requested parameters of
925 : * this level.
926 : */
927 688 : if (root->plan_params)
928 0 : elog(ERROR, "unexpected outer reference in CTE query");
929 :
930 : /*
931 : * Select best Path and turn it into a Plan. At least for now, there
932 : * seems no reason to postpone doing that.
933 : */
934 688 : final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
935 688 : best_path = final_rel->cheapest_total_path;
936 :
937 688 : plan = create_plan(subroot, best_path);
938 :
939 : /*
940 : * Make a SubPlan node for it. This is just enough unlike
941 : * build_subplan that we can't share code.
942 : *
943 : * Note plan_id, plan_name, and cost fields are set further down.
944 : */
945 688 : splan = makeNode(SubPlan);
946 688 : splan->subLinkType = CTE_SUBLINK;
947 688 : splan->testexpr = NULL;
948 688 : splan->paramIds = NIL;
949 688 : get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
950 : &splan->firstColCollation);
951 688 : splan->useHashTable = false;
952 688 : splan->unknownEqFalse = false;
953 :
954 : /*
955 : * CTE scans are not considered for parallelism (cf
956 : * set_rel_consider_parallel), and even if they were, initPlans aren't
957 : * parallel-safe.
958 : */
959 688 : splan->parallel_safe = false;
960 688 : splan->setParam = NIL;
961 688 : splan->parParam = NIL;
962 688 : splan->args = NIL;
963 :
964 : /*
965 : * The node can't have any inputs (since it's an initplan), so the
966 : * parParam and args lists remain empty. (It could contain references
967 : * to earlier CTEs' output param IDs, but CTE outputs are not
968 : * propagated via the args list.)
969 : */
970 :
971 : /*
972 : * Assign a param ID to represent the CTE's output. No ordinary
973 : * "evaluation" of this param slot ever happens, but we use the param
974 : * ID for setParam/chgParam signaling just as if the CTE plan were
975 : * returning a simple scalar output. (Also, the executor abuses the
976 : * ParamExecData slot for this param ID for communication among
977 : * multiple CteScan nodes that might be scanning this CTE.)
978 : */
979 688 : paramid = assign_special_exec_param(root);
980 688 : splan->setParam = list_make1_int(paramid);
981 :
982 : /*
983 : * Add the subplan and its PlannerInfo to the global lists.
984 : */
985 688 : root->glob->subplans = lappend(root->glob->subplans, plan);
986 688 : root->glob->subroots = lappend(root->glob->subroots, subroot);
987 688 : splan->plan_id = list_length(root->glob->subplans);
988 :
989 688 : root->init_plans = lappend(root->init_plans, splan);
990 :
991 688 : root->cte_plan_ids = lappend_int(root->cte_plan_ids, splan->plan_id);
992 :
993 : /* Label the subplan for EXPLAIN purposes */
994 688 : splan->plan_name = psprintf("CTE %s", cte->ctename);
995 :
996 : /* Lastly, fill in the cost estimates for use later */
997 688 : cost_subplan(root, splan, plan);
998 : }
999 1170 : }
1000 :
1001 : /*
1002 : * contain_dml: is any subquery not a plain SELECT?
1003 : *
1004 : * We reject SELECT FOR UPDATE/SHARE as well as INSERT etc.
1005 : */
1006 : static bool
1007 660 : contain_dml(Node *node)
1008 : {
1009 660 : return contain_dml_walker(node, NULL);
1010 : }
1011 :
1012 : static bool
1013 42664 : contain_dml_walker(Node *node, void *context)
1014 : {
1015 42664 : if (node == NULL)
1016 10566 : return false;
1017 32098 : if (IsA(node, Query))
1018 : {
1019 888 : Query *query = (Query *) node;
1020 :
1021 1776 : if (query->commandType != CMD_SELECT ||
1022 888 : query->rowMarks != NIL)
1023 6 : return true;
1024 :
1025 882 : return query_tree_walker(query, contain_dml_walker, context, 0);
1026 : }
1027 31210 : return expression_tree_walker(node, contain_dml_walker, context);
1028 : }
1029 :
1030 : /*
1031 : * contain_outer_selfref: is there an external recursive self-reference?
1032 : */
1033 : static bool
1034 12 : contain_outer_selfref(Node *node)
1035 : {
1036 12 : Index depth = 0;
1037 :
1038 : /*
1039 : * We should be starting with a Query, so that depth will be 1 while
1040 : * examining its immediate contents.
1041 : */
1042 : Assert(IsA(node, Query));
1043 :
1044 12 : return contain_outer_selfref_walker(node, &depth);
1045 : }
1046 :
1047 : static bool
1048 300 : contain_outer_selfref_walker(Node *node, Index *depth)
1049 : {
1050 300 : if (node == NULL)
1051 156 : return false;
1052 144 : if (IsA(node, RangeTblEntry))
1053 : {
1054 16 : RangeTblEntry *rte = (RangeTblEntry *) node;
1055 :
1056 : /*
1057 : * Check for a self-reference to a CTE that's above the Query that our
1058 : * search started at.
1059 : */
1060 24 : if (rte->rtekind == RTE_CTE &&
1061 16 : rte->self_reference &&
1062 8 : rte->ctelevelsup >= *depth)
1063 8 : return true;
1064 8 : return false; /* allow range_table_walker to continue */
1065 : }
1066 128 : if (IsA(node, Query))
1067 : {
1068 : /* Recurse into subquery, tracking nesting depth properly */
1069 16 : Query *query = (Query *) node;
1070 : bool result;
1071 :
1072 16 : (*depth)++;
1073 :
1074 16 : result = query_tree_walker(query, contain_outer_selfref_walker,
1075 : (void *) depth, QTW_EXAMINE_RTES_BEFORE);
1076 :
1077 16 : (*depth)--;
1078 :
1079 16 : return result;
1080 : }
1081 112 : return expression_tree_walker(node, contain_outer_selfref_walker,
1082 : (void *) depth);
1083 : }
1084 :
1085 : /*
1086 : * inline_cte: convert RTE_CTE references to given CTE into RTE_SUBQUERYs
1087 : */
1088 : static void
1089 642 : inline_cte(PlannerInfo *root, CommonTableExpr *cte)
1090 : {
1091 : struct inline_cte_walker_context context;
1092 :
1093 642 : context.ctename = cte->ctename;
1094 : /* Start at levelsup = -1 because we'll immediately increment it */
1095 642 : context.levelsup = -1;
1096 642 : context.refcount = cte->cterefcount;
1097 642 : context.ctequery = castNode(Query, cte->ctequery);
1098 :
1099 642 : (void) inline_cte_walker((Node *) root->parse, &context);
1100 :
1101 : /* Assert we replaced all references */
1102 : Assert(context.refcount == 0);
1103 642 : }
1104 :
1105 : static bool
1106 115972 : inline_cte_walker(Node *node, inline_cte_walker_context *context)
1107 : {
1108 115972 : if (node == NULL)
1109 32968 : return false;
1110 83004 : if (IsA(node, Query))
1111 : {
1112 2978 : Query *query = (Query *) node;
1113 :
1114 2978 : context->levelsup++;
1115 :
1116 : /*
1117 : * Visit the query's RTE nodes after their contents; otherwise
1118 : * query_tree_walker would descend into the newly inlined CTE query,
1119 : * which we don't want.
1120 : */
1121 2978 : (void) query_tree_walker(query, inline_cte_walker, context,
1122 : QTW_EXAMINE_RTES_AFTER);
1123 :
1124 2978 : context->levelsup--;
1125 :
1126 2978 : return false;
1127 : }
1128 80026 : else if (IsA(node, RangeTblEntry))
1129 : {
1130 4660 : RangeTblEntry *rte = (RangeTblEntry *) node;
1131 :
1132 5718 : if (rte->rtekind == RTE_CTE &&
1133 1704 : strcmp(rte->ctename, context->ctename) == 0 &&
1134 646 : rte->ctelevelsup == context->levelsup)
1135 : {
1136 : /*
1137 : * Found a reference to replace. Generate a copy of the CTE query
1138 : * with appropriate level adjustment for outer references (e.g.,
1139 : * to other CTEs).
1140 : */
1141 646 : Query *newquery = copyObject(context->ctequery);
1142 :
1143 646 : if (context->levelsup > 0)
1144 482 : IncrementVarSublevelsUp((Node *) newquery, context->levelsup, 1);
1145 :
1146 : /*
1147 : * Convert the RTE_CTE RTE into a RTE_SUBQUERY.
1148 : *
1149 : * Historically, a FOR UPDATE clause has been treated as extending
1150 : * into views and subqueries, but not into CTEs. We preserve this
1151 : * distinction by not trying to push rowmarks into the new
1152 : * subquery.
1153 : */
1154 646 : rte->rtekind = RTE_SUBQUERY;
1155 646 : rte->subquery = newquery;
1156 646 : rte->security_barrier = false;
1157 :
1158 : /* Zero out CTE-specific fields */
1159 646 : rte->ctename = NULL;
1160 646 : rte->ctelevelsup = 0;
1161 646 : rte->self_reference = false;
1162 646 : rte->coltypes = NIL;
1163 646 : rte->coltypmods = NIL;
1164 646 : rte->colcollations = NIL;
1165 :
1166 : /* Count the number of replacements we've done */
1167 646 : context->refcount--;
1168 : }
1169 :
1170 4660 : return false;
1171 : }
1172 :
1173 75366 : return expression_tree_walker(node, inline_cte_walker, context);
1174 : }
1175 :
1176 :
1177 : /*
1178 : * convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
1179 : *
1180 : * The caller has found an ANY SubLink at the top level of one of the query's
1181 : * qual clauses, but has not checked the properties of the SubLink further.
1182 : * Decide whether it is appropriate to process this SubLink in join style.
1183 : * If so, form a JoinExpr and return it. Return NULL if the SubLink cannot
1184 : * be converted to a join.
1185 : *
1186 : * The only non-obvious input parameter is available_rels: this is the set
1187 : * of query rels that can safely be referenced in the sublink expression.
1188 : * (We must restrict this to avoid changing the semantics when a sublink
1189 : * is present in an outer join's ON qual.) The conversion must fail if
1190 : * the converted qual would reference any but these parent-query relids.
1191 : *
1192 : * On success, the returned JoinExpr has larg = NULL and rarg = the jointree
1193 : * item representing the pulled-up subquery. The caller must set larg to
1194 : * represent the relation(s) on the lefthand side of the new join, and insert
1195 : * the JoinExpr into the upper query's jointree at an appropriate place
1196 : * (typically, where the lefthand relation(s) had been). Note that the
1197 : * passed-in SubLink must also be removed from its original position in the
1198 : * query quals, since the quals of the returned JoinExpr replace it.
1199 : * (Notionally, we replace the SubLink with a constant TRUE, then elide the
1200 : * redundant constant from the qual.)
1201 : *
1202 : * On success, the caller is also responsible for recursively applying
1203 : * pull_up_sublinks processing to the rarg and quals of the returned JoinExpr.
1204 : * (On failure, there is no need to do anything, since pull_up_sublinks will
1205 : * be applied when we recursively plan the sub-select.)
1206 : *
1207 : * Side effects of a successful conversion include adding the SubLink's
1208 : * subselect to the query's rangetable, so that it can be referenced in
1209 : * the JoinExpr's rarg.
1210 : */
1211 : JoinExpr *
1212 608 : convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
1213 : Relids available_rels)
1214 : {
1215 : JoinExpr *result;
1216 608 : Query *parse = root->parse;
1217 608 : Query *subselect = (Query *) sublink->subselect;
1218 : Relids upper_varnos;
1219 : int rtindex;
1220 : RangeTblEntry *rte;
1221 : RangeTblRef *rtr;
1222 : List *subquery_vars;
1223 : Node *quals;
1224 : ParseState *pstate;
1225 :
1226 : Assert(sublink->subLinkType == ANY_SUBLINK);
1227 :
1228 : /*
1229 : * The sub-select must not refer to any Vars of the parent query. (Vars of
1230 : * higher levels should be okay, though.)
1231 : */
1232 608 : if (contain_vars_of_level((Node *) subselect, 1))
1233 40 : return NULL;
1234 :
1235 : /*
1236 : * The test expression must contain some Vars of the parent query, else
1237 : * it's not gonna be a join. (Note that it won't have Vars referring to
1238 : * the subquery, rather Params.)
1239 : */
1240 568 : upper_varnos = pull_varnos(sublink->testexpr);
1241 568 : if (bms_is_empty(upper_varnos))
1242 8 : return NULL;
1243 :
1244 : /*
1245 : * However, it can't refer to anything outside available_rels.
1246 : */
1247 560 : if (!bms_is_subset(upper_varnos, available_rels))
1248 0 : return NULL;
1249 :
1250 : /*
1251 : * The combining operators and left-hand expressions mustn't be volatile.
1252 : */
1253 560 : if (contain_volatile_functions(sublink->testexpr))
1254 0 : return NULL;
1255 :
1256 : /* Create a dummy ParseState for addRangeTableEntryForSubquery */
1257 560 : pstate = make_parsestate(NULL);
1258 :
1259 : /*
1260 : * Okay, pull up the sub-select into upper range table.
1261 : *
1262 : * We rely here on the assumption that the outer query has no references
1263 : * to the inner (necessarily true, other than the Vars that we build
1264 : * below). Therefore this is a lot easier than what pull_up_subqueries has
1265 : * to go through.
1266 : */
1267 560 : rte = addRangeTableEntryForSubquery(pstate,
1268 : subselect,
1269 : makeAlias("ANY_subquery", NIL),
1270 : false,
1271 : false);
1272 560 : parse->rtable = lappend(parse->rtable, rte);
1273 560 : rtindex = list_length(parse->rtable);
1274 :
1275 : /*
1276 : * Form a RangeTblRef for the pulled-up sub-select.
1277 : */
1278 560 : rtr = makeNode(RangeTblRef);
1279 560 : rtr->rtindex = rtindex;
1280 :
1281 : /*
1282 : * Build a list of Vars representing the subselect outputs.
1283 : */
1284 560 : subquery_vars = generate_subquery_vars(root,
1285 : subselect->targetList,
1286 : rtindex);
1287 :
1288 : /*
1289 : * Build the new join's qual expression, replacing Params with these Vars.
1290 : */
1291 560 : quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
1292 :
1293 : /*
1294 : * And finally, build the JoinExpr node.
1295 : */
1296 560 : result = makeNode(JoinExpr);
1297 560 : result->jointype = JOIN_SEMI;
1298 560 : result->isNatural = false;
1299 560 : result->larg = NULL; /* caller must fill this in */
1300 560 : result->rarg = (Node *) rtr;
1301 560 : result->usingClause = NIL;
1302 560 : result->quals = quals;
1303 560 : result->alias = NULL;
1304 560 : result->rtindex = 0; /* we don't need an RTE for it */
1305 :
1306 560 : return result;
1307 : }
1308 :
1309 : /*
1310 : * convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
1311 : *
1312 : * The API of this function is identical to convert_ANY_sublink_to_join's,
1313 : * except that we also support the case where the caller has found NOT EXISTS,
1314 : * so we need an additional input parameter "under_not".
1315 : */
1316 : JoinExpr *
1317 7714 : convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
1318 : bool under_not, Relids available_rels)
1319 : {
1320 : JoinExpr *result;
1321 7714 : Query *parse = root->parse;
1322 7714 : Query *subselect = (Query *) sublink->subselect;
1323 : Node *whereClause;
1324 : int rtoffset;
1325 : int varno;
1326 : Relids clause_varnos;
1327 : Relids upper_varnos;
1328 :
1329 : Assert(sublink->subLinkType == EXISTS_SUBLINK);
1330 :
1331 : /*
1332 : * Can't flatten if it contains WITH. (We could arrange to pull up the
1333 : * WITH into the parent query's cteList, but that risks changing the
1334 : * semantics, since a WITH ought to be executed once per associated query
1335 : * call.) Note that convert_ANY_sublink_to_join doesn't have to reject
1336 : * this case, since it just produces a subquery RTE that doesn't have to
1337 : * get flattened into the parent query.
1338 : */
1339 7714 : if (subselect->cteList)
1340 0 : return NULL;
1341 :
1342 : /*
1343 : * Copy the subquery so we can modify it safely (see comments in
1344 : * make_subplan).
1345 : */
1346 7714 : subselect = copyObject(subselect);
1347 :
1348 : /*
1349 : * See if the subquery can be simplified based on the knowledge that it's
1350 : * being used in EXISTS(). If we aren't able to get rid of its
1351 : * targetlist, we have to fail, because the pullup operation leaves us
1352 : * with noplace to evaluate the targetlist.
1353 : */
1354 7714 : if (!simplify_EXISTS_query(root, subselect))
1355 18 : return NULL;
1356 :
1357 : /*
1358 : * Separate out the WHERE clause. (We could theoretically also remove
1359 : * top-level plain JOIN/ON clauses, but it's probably not worth the
1360 : * trouble.)
1361 : */
1362 7696 : whereClause = subselect->jointree->quals;
1363 7696 : subselect->jointree->quals = NULL;
1364 :
1365 : /*
1366 : * The rest of the sub-select must not refer to any Vars of the parent
1367 : * query. (Vars of higher levels should be okay, though.)
1368 : */
1369 7696 : if (contain_vars_of_level((Node *) subselect, 1))
1370 0 : return NULL;
1371 :
1372 : /*
1373 : * On the other hand, the WHERE clause must contain some Vars of the
1374 : * parent query, else it's not gonna be a join.
1375 : */
1376 7696 : if (!contain_vars_of_level(whereClause, 1))
1377 40 : return NULL;
1378 :
1379 : /*
1380 : * We don't risk optimizing if the WHERE clause is volatile, either.
1381 : */
1382 7656 : if (contain_volatile_functions(whereClause))
1383 0 : return NULL;
1384 :
1385 : /*
1386 : * The subquery must have a nonempty jointree, but we can make it so.
1387 : */
1388 7656 : replace_empty_jointree(subselect);
1389 :
1390 : /*
1391 : * Prepare to pull up the sub-select into top range table.
1392 : *
1393 : * We rely here on the assumption that the outer query has no references
1394 : * to the inner (necessarily true). Therefore this is a lot easier than
1395 : * what pull_up_subqueries has to go through.
1396 : *
1397 : * In fact, it's even easier than what convert_ANY_sublink_to_join has to
1398 : * do. The machinations of simplify_EXISTS_query ensured that there is
1399 : * nothing interesting in the subquery except an rtable and jointree, and
1400 : * even the jointree FromExpr no longer has quals. So we can just append
1401 : * the rtable to our own and use the FromExpr in our jointree. But first,
1402 : * adjust all level-zero varnos in the subquery to account for the rtable
1403 : * merger.
1404 : */
1405 7656 : rtoffset = list_length(parse->rtable);
1406 7656 : OffsetVarNodes((Node *) subselect, rtoffset, 0);
1407 7656 : OffsetVarNodes(whereClause, rtoffset, 0);
1408 :
1409 : /*
1410 : * Upper-level vars in subquery will now be one level closer to their
1411 : * parent than before; in particular, anything that had been level 1
1412 : * becomes level zero.
1413 : */
1414 7656 : IncrementVarSublevelsUp((Node *) subselect, -1, 1);
1415 7656 : IncrementVarSublevelsUp(whereClause, -1, 1);
1416 :
1417 : /*
1418 : * Now that the WHERE clause is adjusted to match the parent query
1419 : * environment, we can easily identify all the level-zero rels it uses.
1420 : * The ones <= rtoffset belong to the upper query; the ones > rtoffset do
1421 : * not.
1422 : */
1423 7656 : clause_varnos = pull_varnos(whereClause);
1424 7656 : upper_varnos = NULL;
1425 30636 : while ((varno = bms_first_member(clause_varnos)) >= 0)
1426 : {
1427 15324 : if (varno <= rtoffset)
1428 7672 : upper_varnos = bms_add_member(upper_varnos, varno);
1429 : }
1430 7656 : bms_free(clause_varnos);
1431 : Assert(!bms_is_empty(upper_varnos));
1432 :
1433 : /*
1434 : * Now that we've got the set of upper-level varnos, we can make the last
1435 : * check: only available_rels can be referenced.
1436 : */
1437 7656 : if (!bms_is_subset(upper_varnos, available_rels))
1438 0 : return NULL;
1439 :
1440 : /* Now we can attach the modified subquery rtable to the parent */
1441 7656 : parse->rtable = list_concat(parse->rtable, subselect->rtable);
1442 :
1443 : /*
1444 : * And finally, build the JoinExpr node.
1445 : */
1446 7656 : result = makeNode(JoinExpr);
1447 7656 : result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
1448 7656 : result->isNatural = false;
1449 7656 : result->larg = NULL; /* caller must fill this in */
1450 : /* flatten out the FromExpr node if it's useless */
1451 7656 : if (list_length(subselect->jointree->fromlist) == 1)
1452 7652 : result->rarg = (Node *) linitial(subselect->jointree->fromlist);
1453 : else
1454 4 : result->rarg = (Node *) subselect->jointree;
1455 7656 : result->usingClause = NIL;
1456 7656 : result->quals = whereClause;
1457 7656 : result->alias = NULL;
1458 7656 : result->rtindex = 0; /* we don't need an RTE for it */
1459 :
1460 7656 : return result;
1461 : }
1462 :
1463 : /*
1464 : * simplify_EXISTS_query: remove any useless stuff in an EXISTS's subquery
1465 : *
1466 : * The only thing that matters about an EXISTS query is whether it returns
1467 : * zero or more than zero rows. Therefore, we can remove certain SQL features
1468 : * that won't affect that. The only part that is really likely to matter in
1469 : * typical usage is simplifying the targetlist: it's a common habit to write
1470 : * "SELECT * FROM" even though there is no need to evaluate any columns.
1471 : *
1472 : * Note: by suppressing the targetlist we could cause an observable behavioral
1473 : * change, namely that any errors that might occur in evaluating the tlist
1474 : * won't occur, nor will other side-effects of volatile functions. This seems
1475 : * unlikely to bother anyone in practice.
1476 : *
1477 : * Returns true if was able to discard the targetlist, else false.
1478 : */
1479 : static bool
1480 10738 : simplify_EXISTS_query(PlannerInfo *root, Query *query)
1481 : {
1482 : /*
1483 : * We don't try to simplify at all if the query uses set operations,
1484 : * aggregates, grouping sets, SRFs, modifying CTEs, HAVING, OFFSET, or FOR
1485 : * UPDATE/SHARE; none of these seem likely in normal usage and their
1486 : * possible effects are complex. (Note: we could ignore an "OFFSET 0"
1487 : * clause, but that traditionally is used as an optimization fence, so we
1488 : * don't.)
1489 : */
1490 21476 : if (query->commandType != CMD_SELECT ||
1491 21476 : query->setOperations ||
1492 21476 : query->hasAggs ||
1493 21476 : query->groupingSets ||
1494 21476 : query->hasWindowFuncs ||
1495 21476 : query->hasTargetSRFs ||
1496 21476 : query->hasModifyingCTE ||
1497 21476 : query->havingQual ||
1498 21476 : query->limitOffset ||
1499 10738 : query->rowMarks)
1500 28 : return false;
1501 :
1502 : /*
1503 : * LIMIT with a constant positive (or NULL) value doesn't affect the
1504 : * semantics of EXISTS, so let's ignore such clauses. This is worth doing
1505 : * because people accustomed to certain other DBMSes may be in the habit
1506 : * of writing EXISTS(SELECT ... LIMIT 1) as an optimization. If there's a
1507 : * LIMIT with anything else as argument, though, we can't simplify.
1508 : */
1509 10710 : if (query->limitCount)
1510 : {
1511 : /*
1512 : * The LIMIT clause has not yet been through eval_const_expressions,
1513 : * so we have to apply that here. It might seem like this is a waste
1514 : * of cycles, since the only case plausibly worth worrying about is
1515 : * "LIMIT 1" ... but what we'll actually see is "LIMIT int8(1::int4)",
1516 : * so we have to fold constants or we're not going to recognize it.
1517 : */
1518 16 : Node *node = eval_const_expressions(root, query->limitCount);
1519 : Const *limit;
1520 :
1521 : /* Might as well update the query if we simplified the clause. */
1522 16 : query->limitCount = node;
1523 :
1524 16 : if (!IsA(node, Const))
1525 0 : return false;
1526 :
1527 16 : limit = (Const *) node;
1528 : Assert(limit->consttype == INT8OID);
1529 16 : if (!limit->constisnull && DatumGetInt64(limit->constvalue) <= 0)
1530 8 : return false;
1531 :
1532 : /* Whether or not the targetlist is safe, we can drop the LIMIT. */
1533 8 : query->limitCount = NULL;
1534 : }
1535 :
1536 : /*
1537 : * Otherwise, we can throw away the targetlist, as well as any GROUP,
1538 : * WINDOW, DISTINCT, and ORDER BY clauses; none of those clauses will
1539 : * change a nonzero-rows result to zero rows or vice versa. (Furthermore,
1540 : * since our parsetree representation of these clauses depends on the
1541 : * targetlist, we'd better throw them away if we drop the targetlist.)
1542 : */
1543 10702 : query->targetList = NIL;
1544 10702 : query->groupClause = NIL;
1545 10702 : query->windowClause = NIL;
1546 10702 : query->distinctClause = NIL;
1547 10702 : query->sortClause = NIL;
1548 10702 : query->hasDistinctOn = false;
1549 :
1550 10702 : return true;
1551 : }
1552 :
1553 : /*
1554 : * convert_EXISTS_to_ANY: try to convert EXISTS to a hashable ANY sublink
1555 : *
1556 : * The subselect is expected to be a fresh copy that we can munge up,
1557 : * and to have been successfully passed through simplify_EXISTS_query.
1558 : *
1559 : * On success, the modified subselect is returned, and we store a suitable
1560 : * upper-level test expression at *testexpr, plus a list of the subselect's
1561 : * output Params at *paramIds. (The test expression is already Param-ified
1562 : * and hence need not go through convert_testexpr, which is why we have to
1563 : * deal with the Param IDs specially.)
1564 : *
1565 : * On failure, returns NULL.
1566 : */
1567 : static Query *
1568 1424 : convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
1569 : Node **testexpr, List **paramIds)
1570 : {
1571 : Node *whereClause;
1572 : List *leftargs,
1573 : *rightargs,
1574 : *opids,
1575 : *opcollations,
1576 : *newWhere,
1577 : *tlist,
1578 : *testlist,
1579 : *paramids;
1580 : ListCell *lc,
1581 : *rc,
1582 : *oc,
1583 : *cc;
1584 : AttrNumber resno;
1585 :
1586 : /*
1587 : * Query must not require a targetlist, since we have to insert a new one.
1588 : * Caller should have dealt with the case already.
1589 : */
1590 : Assert(subselect->targetList == NIL);
1591 :
1592 : /*
1593 : * Separate out the WHERE clause. (We could theoretically also remove
1594 : * top-level plain JOIN/ON clauses, but it's probably not worth the
1595 : * trouble.)
1596 : */
1597 1424 : whereClause = subselect->jointree->quals;
1598 1424 : subselect->jointree->quals = NULL;
1599 :
1600 : /*
1601 : * The rest of the sub-select must not refer to any Vars of the parent
1602 : * query. (Vars of higher levels should be okay, though.)
1603 : *
1604 : * Note: we need not check for Aggrefs separately because we know the
1605 : * sub-select is as yet unoptimized; any uplevel Aggref must therefore
1606 : * contain an uplevel Var reference. This is not the case below ...
1607 : */
1608 1424 : if (contain_vars_of_level((Node *) subselect, 1))
1609 158 : return NULL;
1610 :
1611 : /*
1612 : * We don't risk optimizing if the WHERE clause is volatile, either.
1613 : */
1614 1266 : if (contain_volatile_functions(whereClause))
1615 0 : return NULL;
1616 :
1617 : /*
1618 : * Clean up the WHERE clause by doing const-simplification etc on it.
1619 : * Aside from simplifying the processing we're about to do, this is
1620 : * important for being able to pull chunks of the WHERE clause up into the
1621 : * parent query. Since we are invoked partway through the parent's
1622 : * preprocess_expression() work, earlier steps of preprocess_expression()
1623 : * wouldn't get applied to the pulled-up stuff unless we do them here. For
1624 : * the parts of the WHERE clause that get put back into the child query,
1625 : * this work is partially duplicative, but it shouldn't hurt.
1626 : *
1627 : * Note: we do not run flatten_join_alias_vars. This is OK because any
1628 : * parent aliases were flattened already, and we're not going to pull any
1629 : * child Vars (of any description) into the parent.
1630 : *
1631 : * Note: passing the parent's root to eval_const_expressions is
1632 : * technically wrong, but we can get away with it since only the
1633 : * boundParams (if any) are used, and those would be the same in a
1634 : * subroot.
1635 : */
1636 1266 : whereClause = eval_const_expressions(root, whereClause);
1637 1266 : whereClause = (Node *) canonicalize_qual((Expr *) whereClause, false);
1638 1266 : whereClause = (Node *) make_ands_implicit((Expr *) whereClause);
1639 :
1640 : /*
1641 : * We now have a flattened implicit-AND list of clauses, which we try to
1642 : * break apart into "outervar = innervar" hash clauses. Anything that
1643 : * can't be broken apart just goes back into the newWhere list. Note that
1644 : * we aren't trying hard yet to ensure that we have only outer or only
1645 : * inner on each side; we'll check that if we get to the end.
1646 : */
1647 1266 : leftargs = rightargs = opids = opcollations = newWhere = NIL;
1648 5164 : foreach(lc, (List *) whereClause)
1649 : {
1650 3898 : OpExpr *expr = (OpExpr *) lfirst(lc);
1651 :
1652 6712 : if (IsA(expr, OpExpr) &&
1653 2814 : hash_ok_operator(expr))
1654 : {
1655 2498 : Node *leftarg = (Node *) linitial(expr->args);
1656 2498 : Node *rightarg = (Node *) lsecond(expr->args);
1657 :
1658 2498 : if (contain_vars_of_level(leftarg, 1))
1659 : {
1660 168 : leftargs = lappend(leftargs, leftarg);
1661 168 : rightargs = lappend(rightargs, rightarg);
1662 168 : opids = lappend_oid(opids, expr->opno);
1663 168 : opcollations = lappend_oid(opcollations, expr->inputcollid);
1664 168 : continue;
1665 : }
1666 2330 : if (contain_vars_of_level(rightarg, 1))
1667 : {
1668 : /*
1669 : * We must commute the clause to put the outer var on the
1670 : * left, because the hashing code in nodeSubplan.c expects
1671 : * that. This probably shouldn't ever fail, since hashable
1672 : * operators ought to have commutators, but be paranoid.
1673 : */
1674 1406 : expr->opno = get_commutator(expr->opno);
1675 1406 : if (OidIsValid(expr->opno) && hash_ok_operator(expr))
1676 : {
1677 1406 : leftargs = lappend(leftargs, rightarg);
1678 1406 : rightargs = lappend(rightargs, leftarg);
1679 1406 : opids = lappend_oid(opids, expr->opno);
1680 1406 : opcollations = lappend_oid(opcollations, expr->inputcollid);
1681 1406 : continue;
1682 : }
1683 : /* If no commutator, no chance to optimize the WHERE clause */
1684 0 : return NULL;
1685 : }
1686 : }
1687 : /* Couldn't handle it as a hash clause */
1688 2324 : newWhere = lappend(newWhere, expr);
1689 : }
1690 :
1691 : /*
1692 : * If we didn't find anything we could convert, fail.
1693 : */
1694 1266 : if (leftargs == NIL)
1695 156 : return NULL;
1696 :
1697 : /*
1698 : * There mustn't be any parent Vars or Aggs in the stuff that we intend to
1699 : * put back into the child query. Note: you might think we don't need to
1700 : * check for Aggs separately, because an uplevel Agg must contain an
1701 : * uplevel Var in its argument. But it is possible that the uplevel Var
1702 : * got optimized away by eval_const_expressions. Consider
1703 : *
1704 : * SUM(CASE WHEN false THEN uplevelvar ELSE 0 END)
1705 : */
1706 2220 : if (contain_vars_of_level((Node *) newWhere, 1) ||
1707 1110 : contain_vars_of_level((Node *) rightargs, 1))
1708 0 : return NULL;
1709 1122 : if (root->parse->hasAggs &&
1710 24 : (contain_aggs_of_level((Node *) newWhere, 1) ||
1711 12 : contain_aggs_of_level((Node *) rightargs, 1)))
1712 0 : return NULL;
1713 :
1714 : /*
1715 : * And there can't be any child Vars in the stuff we intend to pull up.
1716 : * (Note: we'd need to check for child Aggs too, except we know the child
1717 : * has no aggs at all because of simplify_EXISTS_query's check. The same
1718 : * goes for window functions.)
1719 : */
1720 1110 : if (contain_vars_of_level((Node *) leftargs, 0))
1721 0 : return NULL;
1722 :
1723 : /*
1724 : * Also reject sublinks in the stuff we intend to pull up. (It might be
1725 : * possible to support this, but doesn't seem worth the complication.)
1726 : */
1727 1110 : if (contain_subplans((Node *) leftargs))
1728 0 : return NULL;
1729 :
1730 : /*
1731 : * Okay, adjust the sublevelsup in the stuff we're pulling up.
1732 : */
1733 1110 : IncrementVarSublevelsUp((Node *) leftargs, -1, 1);
1734 :
1735 : /*
1736 : * Put back any child-level-only WHERE clauses.
1737 : */
1738 1110 : if (newWhere)
1739 1006 : subselect->jointree->quals = (Node *) make_ands_explicit(newWhere);
1740 :
1741 : /*
1742 : * Build a new targetlist for the child that emits the expressions we
1743 : * need. Concurrently, build a testexpr for the parent using Params to
1744 : * reference the child outputs. (Since we generate Params directly here,
1745 : * there will be no need to convert the testexpr in build_subplan.)
1746 : */
1747 1110 : tlist = testlist = paramids = NIL;
1748 1110 : resno = 1;
1749 2684 : forfour(lc, leftargs, rc, rightargs, oc, opids, cc, opcollations)
1750 : {
1751 1574 : Node *leftarg = (Node *) lfirst(lc);
1752 1574 : Node *rightarg = (Node *) lfirst(rc);
1753 1574 : Oid opid = lfirst_oid(oc);
1754 1574 : Oid opcollation = lfirst_oid(cc);
1755 : Param *param;
1756 :
1757 1574 : param = generate_new_exec_param(root,
1758 : exprType(rightarg),
1759 : exprTypmod(rightarg),
1760 : exprCollation(rightarg));
1761 1574 : tlist = lappend(tlist,
1762 1574 : makeTargetEntry((Expr *) rightarg,
1763 1574 : resno++,
1764 : NULL,
1765 : false));
1766 1574 : testlist = lappend(testlist,
1767 1574 : make_opclause(opid, BOOLOID, false,
1768 : (Expr *) leftarg, (Expr *) param,
1769 : InvalidOid, opcollation));
1770 1574 : paramids = lappend_int(paramids, param->paramid);
1771 : }
1772 :
1773 : /* Put everything where it should go, and we're done */
1774 1110 : subselect->targetList = tlist;
1775 1110 : *testexpr = (Node *) make_ands_explicit(testlist);
1776 1110 : *paramIds = paramids;
1777 :
1778 1110 : return subselect;
1779 : }
1780 :
1781 :
1782 : /*
1783 : * Replace correlation vars (uplevel vars) with Params.
1784 : *
1785 : * Uplevel PlaceHolderVars and aggregates are replaced, too.
1786 : *
1787 : * Note: it is critical that this runs immediately after SS_process_sublinks.
1788 : * Since we do not recurse into the arguments of uplevel PHVs and aggregates,
1789 : * they will get copied to the appropriate subplan args list in the parent
1790 : * query with uplevel vars not replaced by Params, but only adjusted in level
1791 : * (see replace_outer_placeholdervar and replace_outer_agg). That's exactly
1792 : * what we want for the vars of the parent level --- but if a PHV's or
1793 : * aggregate's argument contains any further-up variables, they have to be
1794 : * replaced with Params in their turn. That will happen when the parent level
1795 : * runs SS_replace_correlation_vars. Therefore it must do so after expanding
1796 : * its sublinks to subplans. And we don't want any steps in between, else
1797 : * those steps would never get applied to the argument expressions, either in
1798 : * the parent or the child level.
1799 : *
1800 : * Another fairly tricky thing going on here is the handling of SubLinks in
1801 : * the arguments of uplevel PHVs/aggregates. Those are not touched inside the
1802 : * intermediate query level, either. Instead, SS_process_sublinks recurses on
1803 : * them after copying the PHV or Aggref expression into the parent plan level
1804 : * (this is actually taken care of in build_subplan).
1805 : */
1806 : Node *
1807 128076 : SS_replace_correlation_vars(PlannerInfo *root, Node *expr)
1808 : {
1809 : /* No setup needed for tree walk, so away we go */
1810 128076 : return replace_correlation_vars_mutator(expr, root);
1811 : }
1812 :
1813 : static Node *
1814 989730 : replace_correlation_vars_mutator(Node *node, PlannerInfo *root)
1815 : {
1816 989730 : if (node == NULL)
1817 39942 : return NULL;
1818 949788 : if (IsA(node, Var))
1819 : {
1820 243574 : if (((Var *) node)->varlevelsup > 0)
1821 61710 : return (Node *) replace_outer_var(root, (Var *) node);
1822 : }
1823 888078 : if (IsA(node, PlaceHolderVar))
1824 : {
1825 20 : if (((PlaceHolderVar *) node)->phlevelsup > 0)
1826 20 : return (Node *) replace_outer_placeholdervar(root,
1827 : (PlaceHolderVar *) node);
1828 : }
1829 888058 : if (IsA(node, Aggref))
1830 : {
1831 11066 : if (((Aggref *) node)->agglevelsup > 0)
1832 32 : return (Node *) replace_outer_agg(root, (Aggref *) node);
1833 : }
1834 888026 : if (IsA(node, GroupingFunc))
1835 : {
1836 32 : if (((GroupingFunc *) node)->agglevelsup > 0)
1837 16 : return (Node *) replace_outer_grouping(root, (GroupingFunc *) node);
1838 : }
1839 888010 : return expression_tree_mutator(node,
1840 : replace_correlation_vars_mutator,
1841 : (void *) root);
1842 : }
1843 :
1844 : /*
1845 : * Expand SubLinks to SubPlans in the given expression.
1846 : *
1847 : * The isQual argument tells whether or not this expression is a WHERE/HAVING
1848 : * qualifier expression. If it is, any sublinks appearing at top level need
1849 : * not distinguish FALSE from UNKNOWN return values.
1850 : */
1851 : Node *
1852 104148 : SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual)
1853 : {
1854 : process_sublinks_context context;
1855 :
1856 104148 : context.root = root;
1857 104148 : context.isTopQual = isQual;
1858 104148 : return process_sublinks_mutator(expr, &context);
1859 : }
1860 :
1861 : static Node *
1862 1641092 : process_sublinks_mutator(Node *node, process_sublinks_context *context)
1863 : {
1864 : process_sublinks_context locContext;
1865 :
1866 1641092 : locContext.root = context->root;
1867 :
1868 1641092 : if (node == NULL)
1869 84944 : return NULL;
1870 1556148 : if (IsA(node, SubLink))
1871 : {
1872 44072 : SubLink *sublink = (SubLink *) node;
1873 : Node *testexpr;
1874 :
1875 : /*
1876 : * First, recursively process the lefthand-side expressions, if any.
1877 : * They're not top-level anymore.
1878 : */
1879 44072 : locContext.isTopQual = false;
1880 44072 : testexpr = process_sublinks_mutator(sublink->testexpr, &locContext);
1881 :
1882 : /*
1883 : * Now build the SubPlan node and make the expr to return.
1884 : */
1885 88144 : return make_subplan(context->root,
1886 44072 : (Query *) sublink->subselect,
1887 : sublink->subLinkType,
1888 : sublink->subLinkId,
1889 : testexpr,
1890 44072 : context->isTopQual);
1891 : }
1892 :
1893 : /*
1894 : * Don't recurse into the arguments of an outer PHV or aggregate here. Any
1895 : * SubLinks in the arguments have to be dealt with at the outer query
1896 : * level; they'll be handled when build_subplan collects the PHV or Aggref
1897 : * into the arguments to be passed down to the current subplan.
1898 : */
1899 1512076 : if (IsA(node, PlaceHolderVar))
1900 : {
1901 64 : if (((PlaceHolderVar *) node)->phlevelsup > 0)
1902 0 : return node;
1903 : }
1904 1512012 : else if (IsA(node, Aggref))
1905 : {
1906 6234 : if (((Aggref *) node)->agglevelsup > 0)
1907 12 : return node;
1908 : }
1909 :
1910 : /*
1911 : * We should never see a SubPlan expression in the input (since this is
1912 : * the very routine that creates 'em to begin with). We shouldn't find
1913 : * ourselves invoked directly on a Query, either.
1914 : */
1915 : Assert(!IsA(node, SubPlan));
1916 : Assert(!IsA(node, AlternativeSubPlan));
1917 : Assert(!IsA(node, Query));
1918 :
1919 : /*
1920 : * Because make_subplan() could return an AND or OR clause, we have to
1921 : * take steps to preserve AND/OR flatness of a qual. We assume the input
1922 : * has been AND/OR flattened and so we need no recursion here.
1923 : *
1924 : * (Due to the coding here, we will not get called on the List subnodes of
1925 : * an AND; and the input is *not* yet in implicit-AND format. So no check
1926 : * is needed for a bare List.)
1927 : *
1928 : * Anywhere within the top-level AND/OR clause structure, we can tell
1929 : * make_subplan() that NULL and FALSE are interchangeable. So isTopQual
1930 : * propagates down in both cases. (Note that this is unlike the meaning
1931 : * of "top level qual" used in most other places in Postgres.)
1932 : */
1933 1512064 : if (is_andclause(node))
1934 : {
1935 22484 : List *newargs = NIL;
1936 : ListCell *l;
1937 :
1938 : /* Still at qual top-level */
1939 22484 : locContext.isTopQual = context->isTopQual;
1940 :
1941 77370 : foreach(l, ((BoolExpr *) node)->args)
1942 : {
1943 : Node *newarg;
1944 :
1945 54886 : newarg = process_sublinks_mutator(lfirst(l), &locContext);
1946 54886 : if (is_andclause(newarg))
1947 0 : newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
1948 : else
1949 54886 : newargs = lappend(newargs, newarg);
1950 : }
1951 22484 : return (Node *) make_andclause(newargs);
1952 : }
1953 :
1954 1489580 : if (is_orclause(node))
1955 : {
1956 2780 : List *newargs = NIL;
1957 : ListCell *l;
1958 :
1959 : /* Still at qual top-level */
1960 2780 : locContext.isTopQual = context->isTopQual;
1961 :
1962 9084 : foreach(l, ((BoolExpr *) node)->args)
1963 : {
1964 : Node *newarg;
1965 :
1966 6304 : newarg = process_sublinks_mutator(lfirst(l), &locContext);
1967 6304 : if (is_orclause(newarg))
1968 0 : newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
1969 : else
1970 6304 : newargs = lappend(newargs, newarg);
1971 : }
1972 2780 : return (Node *) make_orclause(newargs);
1973 : }
1974 :
1975 : /*
1976 : * If we recurse down through anything other than an AND or OR node, we
1977 : * are definitely not at top qual level anymore.
1978 : */
1979 1486800 : locContext.isTopQual = false;
1980 :
1981 1486800 : return expression_tree_mutator(node,
1982 : process_sublinks_mutator,
1983 : (void *) &locContext);
1984 : }
1985 :
1986 : /*
1987 : * SS_identify_outer_params - identify the Params available from outer levels
1988 : *
1989 : * This must be run after SS_replace_correlation_vars and SS_process_sublinks
1990 : * processing is complete in a given query level as well as all of its
1991 : * descendant levels (which means it's most practical to do it at the end of
1992 : * processing the query level). We compute the set of paramIds that outer
1993 : * levels will make available to this level+descendants, and record it in
1994 : * root->outer_params for use while computing extParam/allParam sets in final
1995 : * plan cleanup. (We can't just compute it then, because the upper levels'
1996 : * plan_params lists are transient and will be gone by then.)
1997 : */
1998 : void
1999 300932 : SS_identify_outer_params(PlannerInfo *root)
2000 : {
2001 : Bitmapset *outer_params;
2002 : PlannerInfo *proot;
2003 : ListCell *l;
2004 :
2005 : /*
2006 : * If no parameters have been assigned anywhere in the tree, we certainly
2007 : * don't need to do anything here.
2008 : */
2009 300932 : if (root->glob->paramExecTypes == NIL)
2010 161318 : return;
2011 :
2012 : /*
2013 : * Scan all query levels above this one to see which parameters are due to
2014 : * be available from them, either because lower query levels have
2015 : * requested them (via plan_params) or because they will be available from
2016 : * initPlans of those levels.
2017 : */
2018 139614 : outer_params = NULL;
2019 181984 : for (proot = root->parent_root; proot != NULL; proot = proot->parent_root)
2020 : {
2021 : /* Include ordinary Var/PHV/Aggref params */
2022 96912 : foreach(l, proot->plan_params)
2023 : {
2024 54542 : PlannerParamItem *pitem = (PlannerParamItem *) lfirst(l);
2025 :
2026 54542 : outer_params = bms_add_member(outer_params, pitem->paramId);
2027 : }
2028 : /* Include any outputs of outer-level initPlans */
2029 43596 : foreach(l, proot->init_plans)
2030 : {
2031 1226 : SubPlan *initsubplan = (SubPlan *) lfirst(l);
2032 : ListCell *l2;
2033 :
2034 2452 : foreach(l2, initsubplan->setParam)
2035 : {
2036 1226 : outer_params = bms_add_member(outer_params, lfirst_int(l2));
2037 : }
2038 : }
2039 : /* Include worktable ID, if a recursive query is being planned */
2040 42370 : if (proot->wt_param_id >= 0)
2041 724 : outer_params = bms_add_member(outer_params, proot->wt_param_id);
2042 : }
2043 139614 : root->outer_params = outer_params;
2044 : }
2045 :
2046 : /*
2047 : * SS_charge_for_initplans - account for initplans in Path costs & parallelism
2048 : *
2049 : * If any initPlans have been created in the current query level, they will
2050 : * get attached to the Plan tree created from whichever Path we select from
2051 : * the given rel. Increment all that rel's Paths' costs to account for them,
2052 : * and make sure the paths get marked as parallel-unsafe, since we can't
2053 : * currently transmit initPlans to parallel workers.
2054 : *
2055 : * This is separate from SS_attach_initplans because we might conditionally
2056 : * create more initPlans during create_plan(), depending on which Path we
2057 : * select. However, Paths that would generate such initPlans are expected
2058 : * to have included their cost already.
2059 : */
2060 : void
2061 300932 : SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel)
2062 : {
2063 : Cost initplan_cost;
2064 : ListCell *lc;
2065 :
2066 : /* Nothing to do if no initPlans */
2067 300932 : if (root->init_plans == NIL)
2068 291928 : return;
2069 :
2070 : /*
2071 : * Compute the cost increment just once, since it will be the same for all
2072 : * Paths. We assume each initPlan gets run once during top plan startup.
2073 : * This is a conservative overestimate, since in fact an initPlan might be
2074 : * executed later than plan startup, or even not at all.
2075 : */
2076 9004 : initplan_cost = 0;
2077 18358 : foreach(lc, root->init_plans)
2078 : {
2079 9354 : SubPlan *initsubplan = (SubPlan *) lfirst(lc);
2080 :
2081 9354 : initplan_cost += initsubplan->startup_cost + initsubplan->per_call_cost;
2082 : }
2083 :
2084 : /*
2085 : * Now adjust the costs and parallel_safe flags.
2086 : */
2087 18044 : foreach(lc, final_rel->pathlist)
2088 : {
2089 9040 : Path *path = (Path *) lfirst(lc);
2090 :
2091 9040 : path->startup_cost += initplan_cost;
2092 9040 : path->total_cost += initplan_cost;
2093 9040 : path->parallel_safe = false;
2094 : }
2095 :
2096 : /*
2097 : * Forget about any partial paths and clear consider_parallel, too;
2098 : * they're not usable if we attached an initPlan.
2099 : */
2100 9004 : final_rel->partial_pathlist = NIL;
2101 9004 : final_rel->consider_parallel = false;
2102 :
2103 : /* We needn't do set_cheapest() here, caller will do it */
2104 : }
2105 :
2106 : /*
2107 : * SS_attach_initplans - attach initplans to topmost plan node
2108 : *
2109 : * Attach any initplans created in the current query level to the specified
2110 : * plan node, which should normally be the topmost node for the query level.
2111 : * (In principle the initPlans could go in any node at or above where they're
2112 : * referenced; but there seems no reason to put them any lower than the
2113 : * topmost node, so we don't bother to track exactly where they came from.)
2114 : * We do not touch the plan node's cost; the initplans should have been
2115 : * accounted for in path costing.
2116 : */
2117 : void
2118 300270 : SS_attach_initplans(PlannerInfo *root, Plan *plan)
2119 : {
2120 300270 : plan->initPlan = root->init_plans;
2121 300270 : }
2122 :
2123 : /*
2124 : * SS_finalize_plan - do final parameter processing for a completed Plan.
2125 : *
2126 : * This recursively computes the extParam and allParam sets for every Plan
2127 : * node in the given plan tree. (Oh, and RangeTblFunction.funcparams too.)
2128 : *
2129 : * We assume that SS_finalize_plan has already been run on any initplans or
2130 : * subplans the plan tree could reference.
2131 : */
2132 : void
2133 154246 : SS_finalize_plan(PlannerInfo *root, Plan *plan)
2134 : {
2135 : /* No setup needed, just recurse through plan tree. */
2136 154246 : (void) finalize_plan(root, plan, -1, root->outer_params, NULL);
2137 154246 : }
2138 :
2139 : /*
2140 : * Recursive processing of all nodes in the plan tree
2141 : *
2142 : * gather_param is the rescan_param of an ancestral Gather/GatherMerge,
2143 : * or -1 if there is none.
2144 : *
2145 : * valid_params is the set of param IDs supplied by outer plan levels
2146 : * that are valid to reference in this plan node or its children.
2147 : *
2148 : * scan_params is a set of param IDs to force scan plan nodes to reference.
2149 : * This is for EvalPlanQual support, and is always NULL at the top of the
2150 : * recursion.
2151 : *
2152 : * The return value is the computed allParam set for the given Plan node.
2153 : * This is just an internal notational convenience: we can add a child
2154 : * plan's allParams to the set of param IDs of interest to this level
2155 : * in the same statement that recurses to that child.
2156 : *
2157 : * Do not scribble on caller's values of valid_params or scan_params!
2158 : *
2159 : * Note: although we attempt to deal with initPlans anywhere in the tree, the
2160 : * logic is not really right. The problem is that a plan node might return an
2161 : * output Param of its initPlan as a targetlist item, in which case it's valid
2162 : * for the parent plan level to reference that same Param; the parent's usage
2163 : * will be converted into a Var referencing the child plan node by setrefs.c.
2164 : * But this function would see the parent's reference as out of scope and
2165 : * complain about it. For now, this does not matter because the planner only
2166 : * attaches initPlans to the topmost plan node in a query level, so the case
2167 : * doesn't arise. If we ever merge this processing into setrefs.c, maybe it
2168 : * can be handled more cleanly.
2169 : */
2170 : static Bitmapset *
2171 1008298 : finalize_plan(PlannerInfo *root, Plan *plan,
2172 : int gather_param,
2173 : Bitmapset *valid_params,
2174 : Bitmapset *scan_params)
2175 : {
2176 : finalize_primnode_context context;
2177 : int locally_added_param;
2178 : Bitmapset *nestloop_params;
2179 : Bitmapset *initExtParam;
2180 : Bitmapset *initSetParam;
2181 : Bitmapset *child_params;
2182 : ListCell *l;
2183 :
2184 1008298 : if (plan == NULL)
2185 621474 : return NULL;
2186 :
2187 386824 : context.root = root;
2188 386824 : context.paramids = NULL; /* initialize set to empty */
2189 386824 : locally_added_param = -1; /* there isn't one */
2190 386824 : nestloop_params = NULL; /* there aren't any */
2191 :
2192 : /*
2193 : * Examine any initPlans to determine the set of external params they
2194 : * reference and the set of output params they supply. (We assume
2195 : * SS_finalize_plan was run on them already.)
2196 : */
2197 386824 : initExtParam = initSetParam = NULL;
2198 396538 : foreach(l, plan->initPlan)
2199 : {
2200 9714 : SubPlan *initsubplan = (SubPlan *) lfirst(l);
2201 9714 : Plan *initplan = planner_subplan_get_plan(root, initsubplan);
2202 : ListCell *l2;
2203 :
2204 9714 : initExtParam = bms_add_members(initExtParam, initplan->extParam);
2205 19444 : foreach(l2, initsubplan->setParam)
2206 : {
2207 9730 : initSetParam = bms_add_member(initSetParam, lfirst_int(l2));
2208 : }
2209 : }
2210 :
2211 : /* Any setParams are validly referenceable in this node and children */
2212 386824 : if (initSetParam)
2213 9332 : valid_params = bms_union(valid_params, initSetParam);
2214 :
2215 : /*
2216 : * When we call finalize_primnode, context.paramids sets are automatically
2217 : * merged together. But when recursing to self, we have to do it the hard
2218 : * way. We want the paramids set to include params in subplans as well as
2219 : * at this level.
2220 : */
2221 :
2222 : /* Find params in targetlist and qual */
2223 386824 : finalize_primnode((Node *) plan->targetlist, &context);
2224 386824 : finalize_primnode((Node *) plan->qual, &context);
2225 :
2226 : /*
2227 : * If it's a parallel-aware scan node, mark it as dependent on the parent
2228 : * Gather/GatherMerge's rescan Param.
2229 : */
2230 386824 : if (plan->parallel_aware)
2231 : {
2232 1248 : if (gather_param < 0)
2233 0 : elog(ERROR, "parallel-aware plan node is not below a Gather");
2234 1248 : context.paramids =
2235 1248 : bms_add_member(context.paramids, gather_param);
2236 : }
2237 :
2238 : /* Check additional node-type-specific fields */
2239 386824 : switch (nodeTag(plan))
2240 : {
2241 : case T_Result:
2242 45660 : finalize_primnode(((Result *) plan)->resconstantqual,
2243 : &context);
2244 45660 : break;
2245 :
2246 : case T_SeqScan:
2247 64724 : context.paramids = bms_add_members(context.paramids, scan_params);
2248 64724 : break;
2249 :
2250 : case T_SampleScan:
2251 36 : finalize_primnode((Node *) ((SampleScan *) plan)->tablesample,
2252 : &context);
2253 36 : context.paramids = bms_add_members(context.paramids, scan_params);
2254 36 : break;
2255 :
2256 : case T_IndexScan:
2257 56292 : finalize_primnode((Node *) ((IndexScan *) plan)->indexqual,
2258 : &context);
2259 56292 : finalize_primnode((Node *) ((IndexScan *) plan)->indexorderby,
2260 : &context);
2261 :
2262 : /*
2263 : * we need not look at indexqualorig, since it will have the same
2264 : * param references as indexqual. Likewise, we can ignore
2265 : * indexorderbyorig.
2266 : */
2267 56292 : context.paramids = bms_add_members(context.paramids, scan_params);
2268 56292 : break;
2269 :
2270 : case T_IndexOnlyScan:
2271 2002 : finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexqual,
2272 : &context);
2273 2002 : finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexorderby,
2274 : &context);
2275 :
2276 : /*
2277 : * we need not look at indextlist, since it cannot contain Params.
2278 : */
2279 2002 : context.paramids = bms_add_members(context.paramids, scan_params);
2280 2002 : break;
2281 :
2282 : case T_BitmapIndexScan:
2283 8178 : finalize_primnode((Node *) ((BitmapIndexScan *) plan)->indexqual,
2284 : &context);
2285 :
2286 : /*
2287 : * we need not look at indexqualorig, since it will have the same
2288 : * param references as indexqual.
2289 : */
2290 8178 : break;
2291 :
2292 : case T_BitmapHeapScan:
2293 8118 : finalize_primnode((Node *) ((BitmapHeapScan *) plan)->bitmapqualorig,
2294 : &context);
2295 8118 : context.paramids = bms_add_members(context.paramids, scan_params);
2296 8118 : break;
2297 :
2298 : case T_TidScan:
2299 364 : finalize_primnode((Node *) ((TidScan *) plan)->tidquals,
2300 : &context);
2301 364 : context.paramids = bms_add_members(context.paramids, scan_params);
2302 364 : break;
2303 :
2304 : case T_SubqueryScan:
2305 : {
2306 4174 : SubqueryScan *sscan = (SubqueryScan *) plan;
2307 : RelOptInfo *rel;
2308 : Bitmapset *subquery_params;
2309 :
2310 : /* We must run finalize_plan on the subquery */
2311 4174 : rel = find_base_rel(root, sscan->scan.scanrelid);
2312 4174 : subquery_params = rel->subroot->outer_params;
2313 4174 : if (gather_param >= 0)
2314 8 : subquery_params = bms_add_member(bms_copy(subquery_params),
2315 : gather_param);
2316 4174 : finalize_plan(rel->subroot, sscan->subplan, gather_param,
2317 : subquery_params, NULL);
2318 :
2319 : /* Now we can add its extParams to the parent's params */
2320 4174 : context.paramids = bms_add_members(context.paramids,
2321 4174 : sscan->subplan->extParam);
2322 : /* We need scan_params too, though */
2323 4174 : context.paramids = bms_add_members(context.paramids,
2324 : scan_params);
2325 : }
2326 4174 : break;
2327 :
2328 : case T_FunctionScan:
2329 : {
2330 22284 : FunctionScan *fscan = (FunctionScan *) plan;
2331 : ListCell *lc;
2332 :
2333 : /*
2334 : * Call finalize_primnode independently on each function
2335 : * expression, so that we can record which params are
2336 : * referenced in each, in order to decide which need
2337 : * re-evaluating during rescan.
2338 : */
2339 44584 : foreach(lc, fscan->functions)
2340 : {
2341 22300 : RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
2342 : finalize_primnode_context funccontext;
2343 :
2344 22300 : funccontext = context;
2345 22300 : funccontext.paramids = NULL;
2346 :
2347 22300 : finalize_primnode(rtfunc->funcexpr, &funccontext);
2348 :
2349 : /* remember results for execution */
2350 22300 : rtfunc->funcparams = funccontext.paramids;
2351 :
2352 : /* add the function's params to the overall set */
2353 22300 : context.paramids = bms_add_members(context.paramids,
2354 22300 : funccontext.paramids);
2355 : }
2356 :
2357 22284 : context.paramids = bms_add_members(context.paramids,
2358 : scan_params);
2359 : }
2360 22284 : break;
2361 :
2362 : case T_TableFuncScan:
2363 96 : finalize_primnode((Node *) ((TableFuncScan *) plan)->tablefunc,
2364 : &context);
2365 96 : context.paramids = bms_add_members(context.paramids, scan_params);
2366 96 : break;
2367 :
2368 : case T_ValuesScan:
2369 2718 : finalize_primnode((Node *) ((ValuesScan *) plan)->values_lists,
2370 : &context);
2371 2718 : context.paramids = bms_add_members(context.paramids, scan_params);
2372 2718 : break;
2373 :
2374 : case T_CteScan:
2375 : {
2376 : /*
2377 : * You might think we should add the node's cteParam to
2378 : * paramids, but we shouldn't because that param is just a
2379 : * linkage mechanism for multiple CteScan nodes for the same
2380 : * CTE; it is never used for changed-param signaling. What we
2381 : * have to do instead is to find the referenced CTE plan and
2382 : * incorporate its external paramids, so that the correct
2383 : * things will happen if the CTE references outer-level
2384 : * variables. See test cases for bug #4902. (We assume
2385 : * SS_finalize_plan was run on the CTE plan already.)
2386 : */
2387 876 : int plan_id = ((CteScan *) plan)->ctePlanId;
2388 : Plan *cteplan;
2389 :
2390 : /* so, do this ... */
2391 876 : if (plan_id < 1 || plan_id > list_length(root->glob->subplans))
2392 0 : elog(ERROR, "could not find plan for CteScan referencing plan ID %d",
2393 : plan_id);
2394 876 : cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
2395 876 : context.paramids =
2396 876 : bms_add_members(context.paramids, cteplan->extParam);
2397 :
2398 : #ifdef NOT_USED
2399 : /* ... but not this */
2400 : context.paramids =
2401 : bms_add_member(context.paramids,
2402 : ((CteScan *) plan)->cteParam);
2403 : #endif
2404 :
2405 876 : context.paramids = bms_add_members(context.paramids,
2406 : scan_params);
2407 : }
2408 876 : break;
2409 :
2410 : case T_WorkTableScan:
2411 320 : context.paramids =
2412 320 : bms_add_member(context.paramids,
2413 : ((WorkTableScan *) plan)->wtParam);
2414 320 : context.paramids = bms_add_members(context.paramids, scan_params);
2415 320 : break;
2416 :
2417 : case T_NamedTuplestoreScan:
2418 208 : context.paramids = bms_add_members(context.paramids, scan_params);
2419 208 : break;
2420 :
2421 : case T_ForeignScan:
2422 : {
2423 492 : ForeignScan *fscan = (ForeignScan *) plan;
2424 :
2425 492 : finalize_primnode((Node *) fscan->fdw_exprs,
2426 : &context);
2427 492 : finalize_primnode((Node *) fscan->fdw_recheck_quals,
2428 : &context);
2429 :
2430 : /* We assume fdw_scan_tlist cannot contain Params */
2431 492 : context.paramids = bms_add_members(context.paramids,
2432 : scan_params);
2433 : }
2434 492 : break;
2435 :
2436 : case T_CustomScan:
2437 : {
2438 0 : CustomScan *cscan = (CustomScan *) plan;
2439 : ListCell *lc;
2440 :
2441 0 : finalize_primnode((Node *) cscan->custom_exprs,
2442 : &context);
2443 : /* We assume custom_scan_tlist cannot contain Params */
2444 0 : context.paramids =
2445 0 : bms_add_members(context.paramids, scan_params);
2446 :
2447 : /* child nodes if any */
2448 0 : foreach(lc, cscan->custom_plans)
2449 : {
2450 0 : context.paramids =
2451 0 : bms_add_members(context.paramids,
2452 0 : finalize_plan(root,
2453 0 : (Plan *) lfirst(lc),
2454 : gather_param,
2455 : valid_params,
2456 : scan_params));
2457 : }
2458 : }
2459 0 : break;
2460 :
2461 : case T_ModifyTable:
2462 : {
2463 69272 : ModifyTable *mtplan = (ModifyTable *) plan;
2464 : ListCell *l;
2465 :
2466 : /* Force descendant scan nodes to reference epqParam */
2467 69272 : locally_added_param = mtplan->epqParam;
2468 69272 : valid_params = bms_add_member(bms_copy(valid_params),
2469 : locally_added_param);
2470 69272 : scan_params = bms_add_member(bms_copy(scan_params),
2471 : locally_added_param);
2472 69272 : finalize_primnode((Node *) mtplan->returningLists,
2473 : &context);
2474 69272 : finalize_primnode((Node *) mtplan->onConflictSet,
2475 : &context);
2476 69272 : finalize_primnode((Node *) mtplan->onConflictWhere,
2477 : &context);
2478 : /* exclRelTlist contains only Vars, doesn't need examination */
2479 139714 : foreach(l, mtplan->plans)
2480 : {
2481 70442 : context.paramids =
2482 70442 : bms_add_members(context.paramids,
2483 70442 : finalize_plan(root,
2484 70442 : (Plan *) lfirst(l),
2485 : gather_param,
2486 : valid_params,
2487 : scan_params));
2488 : }
2489 : }
2490 69272 : break;
2491 :
2492 : case T_Append:
2493 : {
2494 : ListCell *l;
2495 :
2496 7642 : foreach(l, ((Append *) plan)->appendplans)
2497 : {
2498 5464 : context.paramids =
2499 5464 : bms_add_members(context.paramids,
2500 5464 : finalize_plan(root,
2501 5464 : (Plan *) lfirst(l),
2502 : gather_param,
2503 : valid_params,
2504 : scan_params));
2505 : }
2506 : }
2507 2178 : break;
2508 :
2509 : case T_MergeAppend:
2510 : {
2511 : ListCell *l;
2512 :
2513 264 : foreach(l, ((MergeAppend *) plan)->mergeplans)
2514 : {
2515 204 : context.paramids =
2516 204 : bms_add_members(context.paramids,
2517 204 : finalize_plan(root,
2518 204 : (Plan *) lfirst(l),
2519 : gather_param,
2520 : valid_params,
2521 : scan_params));
2522 : }
2523 : }
2524 60 : break;
2525 :
2526 : case T_BitmapAnd:
2527 : {
2528 : ListCell *l;
2529 :
2530 84 : foreach(l, ((BitmapAnd *) plan)->bitmapplans)
2531 : {
2532 56 : context.paramids =
2533 56 : bms_add_members(context.paramids,
2534 56 : finalize_plan(root,
2535 56 : (Plan *) lfirst(l),
2536 : gather_param,
2537 : valid_params,
2538 : scan_params));
2539 : }
2540 : }
2541 28 : break;
2542 :
2543 : case T_BitmapOr:
2544 : {
2545 : ListCell *l;
2546 :
2547 96 : foreach(l, ((BitmapOr *) plan)->bitmapplans)
2548 : {
2549 64 : context.paramids =
2550 64 : bms_add_members(context.paramids,
2551 64 : finalize_plan(root,
2552 64 : (Plan *) lfirst(l),
2553 : gather_param,
2554 : valid_params,
2555 : scan_params));
2556 : }
2557 : }
2558 32 : break;
2559 :
2560 : case T_NestLoop:
2561 : {
2562 : ListCell *l;
2563 :
2564 26956 : finalize_primnode((Node *) ((Join *) plan)->joinqual,
2565 : &context);
2566 : /* collect set of params that will be passed to right child */
2567 45676 : foreach(l, ((NestLoop *) plan)->nestParams)
2568 : {
2569 18720 : NestLoopParam *nlp = (NestLoopParam *) lfirst(l);
2570 :
2571 18720 : nestloop_params = bms_add_member(nestloop_params,
2572 : nlp->paramno);
2573 : }
2574 : }
2575 26956 : break;
2576 :
2577 : case T_MergeJoin:
2578 1024 : finalize_primnode((Node *) ((Join *) plan)->joinqual,
2579 : &context);
2580 1024 : finalize_primnode((Node *) ((MergeJoin *) plan)->mergeclauses,
2581 : &context);
2582 1024 : break;
2583 :
2584 : case T_HashJoin:
2585 15168 : finalize_primnode((Node *) ((Join *) plan)->joinqual,
2586 : &context);
2587 15168 : finalize_primnode((Node *) ((HashJoin *) plan)->hashclauses,
2588 : &context);
2589 15168 : break;
2590 :
2591 : case T_Limit:
2592 1598 : finalize_primnode(((Limit *) plan)->limitOffset,
2593 : &context);
2594 1598 : finalize_primnode(((Limit *) plan)->limitCount,
2595 : &context);
2596 1598 : break;
2597 :
2598 : case T_RecursiveUnion:
2599 : /* child nodes are allowed to reference wtParam */
2600 320 : locally_added_param = ((RecursiveUnion *) plan)->wtParam;
2601 320 : valid_params = bms_add_member(bms_copy(valid_params),
2602 : locally_added_param);
2603 : /* wtParam does *not* get added to scan_params */
2604 320 : break;
2605 :
2606 : case T_LockRows:
2607 : /* Force descendant scan nodes to reference epqParam */
2608 4842 : locally_added_param = ((LockRows *) plan)->epqParam;
2609 4842 : valid_params = bms_add_member(bms_copy(valid_params),
2610 : locally_added_param);
2611 4842 : scan_params = bms_add_member(bms_copy(scan_params),
2612 : locally_added_param);
2613 4842 : break;
2614 :
2615 : case T_Agg:
2616 : {
2617 12658 : Agg *agg = (Agg *) plan;
2618 :
2619 : /*
2620 : * AGG_HASHED plans need to know which Params are referenced
2621 : * in aggregate calls. Do a separate scan to identify them.
2622 : */
2623 12658 : if (agg->aggstrategy == AGG_HASHED)
2624 : {
2625 : finalize_primnode_context aggcontext;
2626 :
2627 836 : aggcontext.root = root;
2628 836 : aggcontext.paramids = NULL;
2629 836 : finalize_agg_primnode((Node *) agg->plan.targetlist,
2630 : &aggcontext);
2631 836 : finalize_agg_primnode((Node *) agg->plan.qual,
2632 : &aggcontext);
2633 836 : agg->aggParams = aggcontext.paramids;
2634 : }
2635 : }
2636 12658 : break;
2637 :
2638 : case T_WindowAgg:
2639 36 : finalize_primnode(((WindowAgg *) plan)->startOffset,
2640 : &context);
2641 36 : finalize_primnode(((WindowAgg *) plan)->endOffset,
2642 : &context);
2643 36 : break;
2644 :
2645 : case T_Gather:
2646 : /* child nodes are allowed to reference rescan_param, if any */
2647 488 : locally_added_param = ((Gather *) plan)->rescan_param;
2648 488 : if (locally_added_param >= 0)
2649 : {
2650 488 : valid_params = bms_add_member(bms_copy(valid_params),
2651 : locally_added_param);
2652 :
2653 : /*
2654 : * We currently don't support nested Gathers. The issue so
2655 : * far as this function is concerned would be how to identify
2656 : * which child nodes depend on which Gather.
2657 : */
2658 : Assert(gather_param < 0);
2659 : /* Pass down rescan_param to child parallel-aware nodes */
2660 488 : gather_param = locally_added_param;
2661 : }
2662 : /* rescan_param does *not* get added to scan_params */
2663 488 : break;
2664 :
2665 : case T_GatherMerge:
2666 : /* child nodes are allowed to reference rescan_param, if any */
2667 136 : locally_added_param = ((GatherMerge *) plan)->rescan_param;
2668 136 : if (locally_added_param >= 0)
2669 : {
2670 136 : valid_params = bms_add_member(bms_copy(valid_params),
2671 : locally_added_param);
2672 :
2673 : /*
2674 : * We currently don't support nested Gathers. The issue so
2675 : * far as this function is concerned would be how to identify
2676 : * which child nodes depend on which Gather.
2677 : */
2678 : Assert(gather_param < 0);
2679 : /* Pass down rescan_param to child parallel-aware nodes */
2680 136 : gather_param = locally_added_param;
2681 : }
2682 : /* rescan_param does *not* get added to scan_params */
2683 136 : break;
2684 :
2685 : case T_ProjectSet:
2686 : case T_Hash:
2687 : case T_Material:
2688 : case T_Sort:
2689 : case T_Unique:
2690 : case T_SetOp:
2691 : case T_Group:
2692 : /* no node-type-specific fields need fixing */
2693 35486 : break;
2694 :
2695 : default:
2696 0 : elog(ERROR, "unrecognized node type: %d",
2697 : (int) nodeTag(plan));
2698 : }
2699 :
2700 : /* Process left and right child plans, if any */
2701 386824 : child_params = finalize_plan(root,
2702 386824 : plan->lefttree,
2703 : gather_param,
2704 : valid_params,
2705 : scan_params);
2706 386824 : context.paramids = bms_add_members(context.paramids, child_params);
2707 :
2708 386824 : if (nestloop_params)
2709 : {
2710 : /* right child can reference nestloop_params as well as valid_params */
2711 34888 : child_params = finalize_plan(root,
2712 17444 : plan->righttree,
2713 : gather_param,
2714 : bms_union(nestloop_params, valid_params),
2715 : scan_params);
2716 : /* ... and they don't count as parameters used at my level */
2717 17444 : child_params = bms_difference(child_params, nestloop_params);
2718 17444 : bms_free(nestloop_params);
2719 : }
2720 : else
2721 : {
2722 : /* easy case */
2723 369380 : child_params = finalize_plan(root,
2724 369380 : plan->righttree,
2725 : gather_param,
2726 : valid_params,
2727 : scan_params);
2728 : }
2729 386824 : context.paramids = bms_add_members(context.paramids, child_params);
2730 :
2731 : /*
2732 : * Any locally generated parameter doesn't count towards its generating
2733 : * plan node's external dependencies. (Note: if we changed valid_params
2734 : * and/or scan_params, we leak those bitmapsets; not worth the notational
2735 : * trouble to clean them up.)
2736 : */
2737 386824 : if (locally_added_param >= 0)
2738 : {
2739 75058 : context.paramids = bms_del_member(context.paramids,
2740 : locally_added_param);
2741 : }
2742 :
2743 : /* Now we have all the paramids referenced in this node and children */
2744 :
2745 386824 : if (!bms_is_subset(context.paramids, valid_params))
2746 0 : elog(ERROR, "plan should not reference subplan's variable");
2747 :
2748 : /*
2749 : * The plan node's allParam and extParam fields should include all its
2750 : * referenced paramids, plus contributions from any child initPlans.
2751 : * However, any setParams of the initPlans should not be present in the
2752 : * parent node's extParams, only in its allParams. (It's possible that
2753 : * some initPlans have extParams that are setParams of other initPlans.)
2754 : */
2755 :
2756 : /* allParam must include initplans' extParams and setParams */
2757 386824 : plan->allParam = bms_union(context.paramids, initExtParam);
2758 386824 : plan->allParam = bms_add_members(plan->allParam, initSetParam);
2759 : /* extParam must include any initplan extParams */
2760 386824 : plan->extParam = bms_union(context.paramids, initExtParam);
2761 : /* but not any initplan setParams */
2762 386824 : plan->extParam = bms_del_members(plan->extParam, initSetParam);
2763 :
2764 : /*
2765 : * For speed at execution time, make sure extParam/allParam are actually
2766 : * NULL if they are empty sets.
2767 : */
2768 386824 : if (bms_is_empty(plan->extParam))
2769 235038 : plan->extParam = NULL;
2770 386824 : if (bms_is_empty(plan->allParam))
2771 225850 : plan->allParam = NULL;
2772 :
2773 386824 : return plan->allParam;
2774 : }
2775 :
2776 : /*
2777 : * finalize_primnode: add IDs of all PARAM_EXEC params appearing in the given
2778 : * expression tree to the result set.
2779 : */
2780 : static bool
2781 7026166 : finalize_primnode(Node *node, finalize_primnode_context *context)
2782 : {
2783 7026166 : if (node == NULL)
2784 842980 : return false;
2785 6183186 : if (IsA(node, Param))
2786 : {
2787 94856 : if (((Param *) node)->paramkind == PARAM_EXEC)
2788 : {
2789 93252 : int paramid = ((Param *) node)->paramid;
2790 :
2791 93252 : context->paramids = bms_add_member(context->paramids, paramid);
2792 : }
2793 94856 : return false; /* no more to do here */
2794 : }
2795 6088330 : if (IsA(node, SubPlan))
2796 : {
2797 45378 : SubPlan *subplan = (SubPlan *) node;
2798 45378 : Plan *plan = planner_subplan_get_plan(context->root, subplan);
2799 : ListCell *lc;
2800 : Bitmapset *subparamids;
2801 :
2802 : /* Recurse into the testexpr, but not into the Plan */
2803 45378 : finalize_primnode(subplan->testexpr, context);
2804 :
2805 : /*
2806 : * Remove any param IDs of output parameters of the subplan that were
2807 : * referenced in the testexpr. These are not interesting for
2808 : * parameter change signaling since we always re-evaluate the subplan.
2809 : * Note that this wouldn't work too well if there might be uses of the
2810 : * same param IDs elsewhere in the plan, but that can't happen because
2811 : * generate_new_exec_param never tries to merge params.
2812 : */
2813 47206 : foreach(lc, subplan->paramIds)
2814 : {
2815 1828 : context->paramids = bms_del_member(context->paramids,
2816 : lfirst_int(lc));
2817 : }
2818 :
2819 : /* Also examine args list */
2820 45378 : finalize_primnode((Node *) subplan->args, context);
2821 :
2822 : /*
2823 : * Add params needed by the subplan to paramids, but excluding those
2824 : * we will pass down to it. (We assume SS_finalize_plan was run on
2825 : * the subplan already.)
2826 : */
2827 45378 : subparamids = bms_copy(plan->extParam);
2828 110102 : foreach(lc, subplan->parParam)
2829 : {
2830 64724 : subparamids = bms_del_member(subparamids, lfirst_int(lc));
2831 : }
2832 45378 : context->paramids = bms_join(context->paramids, subparamids);
2833 :
2834 45378 : return false; /* no more to do here */
2835 : }
2836 6042952 : return expression_tree_walker(node, finalize_primnode,
2837 : (void *) context);
2838 : }
2839 :
2840 : /*
2841 : * finalize_agg_primnode: find all Aggref nodes in the given expression tree,
2842 : * and add IDs of all PARAM_EXEC params appearing within their aggregated
2843 : * arguments to the result set.
2844 : */
2845 : static bool
2846 5648 : finalize_agg_primnode(Node *node, finalize_primnode_context *context)
2847 : {
2848 5648 : if (node == NULL)
2849 804 : return false;
2850 4844 : if (IsA(node, Aggref))
2851 : {
2852 616 : Aggref *agg = (Aggref *) node;
2853 :
2854 : /* we should not consider the direct arguments, if any */
2855 616 : finalize_primnode((Node *) agg->args, context);
2856 616 : finalize_primnode((Node *) agg->aggfilter, context);
2857 616 : return false; /* there can't be any Aggrefs below here */
2858 : }
2859 4228 : return expression_tree_walker(node, finalize_agg_primnode,
2860 : (void *) context);
2861 : }
2862 :
2863 : /*
2864 : * SS_make_initplan_output_param - make a Param for an initPlan's output
2865 : *
2866 : * The plan is expected to return a scalar value of the given type/collation.
2867 : *
2868 : * Note that in some cases the initplan may not ever appear in the finished
2869 : * plan tree. If that happens, we'll have wasted a PARAM_EXEC slot, which
2870 : * is no big deal.
2871 : */
2872 : Param *
2873 422 : SS_make_initplan_output_param(PlannerInfo *root,
2874 : Oid resulttype, int32 resulttypmod,
2875 : Oid resultcollation)
2876 : {
2877 422 : return generate_new_exec_param(root, resulttype,
2878 : resulttypmod, resultcollation);
2879 : }
2880 :
2881 : /*
2882 : * SS_make_initplan_from_plan - given a plan tree, make it an InitPlan
2883 : *
2884 : * We build an EXPR_SUBLINK SubPlan node and put it into the initplan
2885 : * list for the outer query level. A Param that represents the initplan's
2886 : * output has already been assigned using SS_make_initplan_output_param.
2887 : */
2888 : void
2889 360 : SS_make_initplan_from_plan(PlannerInfo *root,
2890 : PlannerInfo *subroot, Plan *plan,
2891 : Param *prm)
2892 : {
2893 : SubPlan *node;
2894 :
2895 : /*
2896 : * Add the subplan and its PlannerInfo to the global lists.
2897 : */
2898 360 : root->glob->subplans = lappend(root->glob->subplans, plan);
2899 360 : root->glob->subroots = lappend(root->glob->subroots, subroot);
2900 :
2901 : /*
2902 : * Create a SubPlan node and add it to the outer list of InitPlans. Note
2903 : * it has to appear after any other InitPlans it might depend on (see
2904 : * comments in ExecReScan).
2905 : */
2906 360 : node = makeNode(SubPlan);
2907 360 : node->subLinkType = EXPR_SUBLINK;
2908 360 : node->plan_id = list_length(root->glob->subplans);
2909 360 : node->plan_name = psprintf("InitPlan %d (returns $%d)",
2910 : node->plan_id, prm->paramid);
2911 360 : get_first_col_type(plan, &node->firstColType, &node->firstColTypmod,
2912 : &node->firstColCollation);
2913 360 : node->setParam = list_make1_int(prm->paramid);
2914 :
2915 360 : root->init_plans = lappend(root->init_plans, node);
2916 :
2917 : /*
2918 : * The node can't have any inputs (since it's an initplan), so the
2919 : * parParam and args lists remain empty.
2920 : */
2921 :
2922 : /* Set costs of SubPlan using info from the plan tree */
2923 360 : cost_subplan(subroot, node, plan);
2924 360 : }
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