Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * parse_cte.c
4 : * handle CTEs (common table expressions) in parser
5 : *
6 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/parser/parse_cte.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include "catalog/pg_collation.h"
18 : #include "catalog/pg_type.h"
19 : #include "nodes/nodeFuncs.h"
20 : #include "parser/analyze.h"
21 : #include "parser/parse_coerce.h"
22 : #include "parser/parse_collate.h"
23 : #include "parser/parse_cte.h"
24 : #include "parser/parse_expr.h"
25 : #include "utils/builtins.h"
26 : #include "utils/lsyscache.h"
27 : #include "utils/typcache.h"
28 :
29 :
30 : /* Enumeration of contexts in which a self-reference is disallowed */
31 : typedef enum
32 : {
33 : RECURSION_OK,
34 : RECURSION_NONRECURSIVETERM, /* inside the left-hand term */
35 : RECURSION_SUBLINK, /* inside a sublink */
36 : RECURSION_OUTERJOIN, /* inside nullable side of an outer join */
37 : RECURSION_INTERSECT, /* underneath INTERSECT (ALL) */
38 : RECURSION_EXCEPT, /* underneath EXCEPT (ALL) */
39 : } RecursionContext;
40 :
41 : /* Associated error messages --- each must have one %s for CTE name */
42 : static const char *const recursion_errormsgs[] = {
43 : /* RECURSION_OK */
44 : NULL,
45 : /* RECURSION_NONRECURSIVETERM */
46 : gettext_noop("recursive reference to query \"%s\" must not appear within its non-recursive term"),
47 : /* RECURSION_SUBLINK */
48 : gettext_noop("recursive reference to query \"%s\" must not appear within a subquery"),
49 : /* RECURSION_OUTERJOIN */
50 : gettext_noop("recursive reference to query \"%s\" must not appear within an outer join"),
51 : /* RECURSION_INTERSECT */
52 : gettext_noop("recursive reference to query \"%s\" must not appear within INTERSECT"),
53 : /* RECURSION_EXCEPT */
54 : gettext_noop("recursive reference to query \"%s\" must not appear within EXCEPT")
55 : };
56 :
57 : /*
58 : * For WITH RECURSIVE, we have to find an ordering of the clause members
59 : * with no forward references, and determine which members are recursive
60 : * (i.e., self-referential). It is convenient to do this with an array
61 : * of CteItems instead of a list of CommonTableExprs.
62 : */
63 : typedef struct CteItem
64 : {
65 : CommonTableExpr *cte; /* One CTE to examine */
66 : int id; /* Its ID number for dependencies */
67 : Bitmapset *depends_on; /* CTEs depended on (not including self) */
68 : } CteItem;
69 :
70 : /* CteState is what we need to pass around in the tree walkers */
71 : typedef struct CteState
72 : {
73 : /* global state: */
74 : ParseState *pstate; /* global parse state */
75 : CteItem *items; /* array of CTEs and extra data */
76 : int numitems; /* number of CTEs */
77 : /* working state during a tree walk: */
78 : int curitem; /* index of item currently being examined */
79 : List *innerwiths; /* list of lists of CommonTableExpr */
80 : /* working state for checkWellFormedRecursion walk only: */
81 : int selfrefcount; /* number of self-references detected */
82 : RecursionContext context; /* context to allow or disallow self-ref */
83 : } CteState;
84 :
85 :
86 : static void analyzeCTE(ParseState *pstate, CommonTableExpr *cte);
87 :
88 : /* Dependency processing functions */
89 : static void makeDependencyGraph(CteState *cstate);
90 : static bool makeDependencyGraphWalker(Node *node, CteState *cstate);
91 : static void TopologicalSort(ParseState *pstate, CteItem *items, int numitems);
92 :
93 : /* Recursion validity checker functions */
94 : static void checkWellFormedRecursion(CteState *cstate);
95 : static bool checkWellFormedRecursionWalker(Node *node, CteState *cstate);
96 : static void checkWellFormedSelectStmt(SelectStmt *stmt, CteState *cstate);
97 :
98 :
99 : /*
100 : * transformWithClause -
101 : * Transform the list of WITH clause "common table expressions" into
102 : * Query nodes.
103 : *
104 : * The result is the list of transformed CTEs to be put into the output
105 : * Query. (This is in fact the same as the ending value of p_ctenamespace,
106 : * but it seems cleaner to not expose that in the function's API.)
107 : */
108 : List *
109 3184 : transformWithClause(ParseState *pstate, WithClause *withClause)
110 : {
111 : ListCell *lc;
112 :
113 : /* Only one WITH clause per query level */
114 : Assert(pstate->p_ctenamespace == NIL);
115 : Assert(pstate->p_future_ctes == NIL);
116 :
117 : /*
118 : * For either type of WITH, there must not be duplicate CTE names in the
119 : * list. Check this right away so we needn't worry later.
120 : *
121 : * Also, tentatively mark each CTE as non-recursive, and initialize its
122 : * reference count to zero, and set pstate->p_hasModifyingCTE if needed.
123 : */
124 7552 : foreach(lc, withClause->ctes)
125 : {
126 4368 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
127 : ListCell *rest;
128 :
129 6698 : for_each_cell(rest, withClause->ctes, lnext(withClause->ctes, lc))
130 : {
131 2330 : CommonTableExpr *cte2 = (CommonTableExpr *) lfirst(rest);
132 :
133 2330 : if (strcmp(cte->ctename, cte2->ctename) == 0)
134 0 : ereport(ERROR,
135 : (errcode(ERRCODE_DUPLICATE_ALIAS),
136 : errmsg("WITH query name \"%s\" specified more than once",
137 : cte2->ctename),
138 : parser_errposition(pstate, cte2->location)));
139 : }
140 :
141 4368 : cte->cterecursive = false;
142 4368 : cte->cterefcount = 0;
143 :
144 4368 : if (!IsA(cte->ctequery, SelectStmt))
145 : {
146 : /* must be a data-modifying statement */
147 : Assert(IsA(cte->ctequery, InsertStmt) ||
148 : IsA(cte->ctequery, UpdateStmt) ||
149 : IsA(cte->ctequery, DeleteStmt) ||
150 : IsA(cte->ctequery, MergeStmt));
151 :
152 390 : pstate->p_hasModifyingCTE = true;
153 : }
154 : }
155 :
156 3184 : if (withClause->recursive)
157 : {
158 : /*
159 : * For WITH RECURSIVE, we rearrange the list elements if needed to
160 : * eliminate forward references. First, build a work array and set up
161 : * the data structure needed by the tree walkers.
162 : */
163 : CteState cstate;
164 : int i;
165 :
166 1214 : cstate.pstate = pstate;
167 1214 : cstate.numitems = list_length(withClause->ctes);
168 1214 : cstate.items = (CteItem *) palloc0(cstate.numitems * sizeof(CteItem));
169 1214 : i = 0;
170 2524 : foreach(lc, withClause->ctes)
171 : {
172 1310 : cstate.items[i].cte = (CommonTableExpr *) lfirst(lc);
173 1310 : cstate.items[i].id = i;
174 1310 : i++;
175 : }
176 :
177 : /*
178 : * Find all the dependencies and sort the CteItems into a safe
179 : * processing order. Also, mark CTEs that contain self-references.
180 : */
181 1214 : makeDependencyGraph(&cstate);
182 :
183 : /*
184 : * Check that recursive queries are well-formed.
185 : */
186 1208 : checkWellFormedRecursion(&cstate);
187 :
188 : /*
189 : * Set up the ctenamespace for parse analysis. Per spec, all the WITH
190 : * items are visible to all others, so stuff them all in before parse
191 : * analysis. We build the list in safe processing order so that the
192 : * planner can process the queries in sequence.
193 : */
194 2218 : for (i = 0; i < cstate.numitems; i++)
195 : {
196 1154 : CommonTableExpr *cte = cstate.items[i].cte;
197 :
198 1154 : pstate->p_ctenamespace = lappend(pstate->p_ctenamespace, cte);
199 : }
200 :
201 : /*
202 : * Do parse analysis in the order determined by the topological sort.
203 : */
204 2092 : for (i = 0; i < cstate.numitems; i++)
205 : {
206 1154 : CommonTableExpr *cte = cstate.items[i].cte;
207 :
208 1154 : analyzeCTE(pstate, cte);
209 : }
210 : }
211 : else
212 : {
213 : /*
214 : * For non-recursive WITH, just analyze each CTE in sequence and then
215 : * add it to the ctenamespace. This corresponds to the spec's
216 : * definition of the scope of each WITH name. However, to allow error
217 : * reports to be aware of the possibility of an erroneous reference,
218 : * we maintain a list in p_future_ctes of the not-yet-visible CTEs.
219 : */
220 1970 : pstate->p_future_ctes = list_copy(withClause->ctes);
221 :
222 5008 : foreach(lc, withClause->ctes)
223 : {
224 3058 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
225 :
226 3058 : analyzeCTE(pstate, cte);
227 3038 : pstate->p_ctenamespace = lappend(pstate->p_ctenamespace, cte);
228 3038 : pstate->p_future_ctes = list_delete_first(pstate->p_future_ctes);
229 : }
230 : }
231 :
232 2888 : return pstate->p_ctenamespace;
233 : }
234 :
235 :
236 : /*
237 : * Perform the actual parse analysis transformation of one CTE. All
238 : * CTEs it depends on have already been loaded into pstate->p_ctenamespace,
239 : * and have been marked with the correct output column names/types.
240 : */
241 : static void
242 4212 : analyzeCTE(ParseState *pstate, CommonTableExpr *cte)
243 : {
244 : Query *query;
245 4212 : CTESearchClause *search_clause = cte->search_clause;
246 4212 : CTECycleClause *cycle_clause = cte->cycle_clause;
247 :
248 : /* Analysis not done already */
249 : Assert(!IsA(cte->ctequery, Query));
250 :
251 : /*
252 : * Before analyzing the CTE's query, we'd better identify the data type of
253 : * the cycle mark column if any, since the query could refer to that.
254 : * Other validity checks on the cycle clause will be done afterwards.
255 : */
256 4212 : if (cycle_clause)
257 : {
258 : TypeCacheEntry *typentry;
259 : Oid op;
260 :
261 126 : cycle_clause->cycle_mark_value =
262 126 : transformExpr(pstate, cycle_clause->cycle_mark_value,
263 : EXPR_KIND_CYCLE_MARK);
264 126 : cycle_clause->cycle_mark_default =
265 126 : transformExpr(pstate, cycle_clause->cycle_mark_default,
266 : EXPR_KIND_CYCLE_MARK);
267 :
268 120 : cycle_clause->cycle_mark_type =
269 126 : select_common_type(pstate,
270 126 : list_make2(cycle_clause->cycle_mark_value,
271 : cycle_clause->cycle_mark_default),
272 : "CYCLE", NULL);
273 120 : cycle_clause->cycle_mark_value =
274 120 : coerce_to_common_type(pstate,
275 : cycle_clause->cycle_mark_value,
276 : cycle_clause->cycle_mark_type,
277 : "CYCLE/SET/TO");
278 120 : cycle_clause->cycle_mark_default =
279 120 : coerce_to_common_type(pstate,
280 : cycle_clause->cycle_mark_default,
281 : cycle_clause->cycle_mark_type,
282 : "CYCLE/SET/DEFAULT");
283 :
284 120 : cycle_clause->cycle_mark_typmod =
285 120 : select_common_typmod(pstate,
286 120 : list_make2(cycle_clause->cycle_mark_value,
287 : cycle_clause->cycle_mark_default),
288 : cycle_clause->cycle_mark_type);
289 :
290 120 : cycle_clause->cycle_mark_collation =
291 120 : select_common_collation(pstate,
292 120 : list_make2(cycle_clause->cycle_mark_value,
293 : cycle_clause->cycle_mark_default),
294 : true);
295 :
296 : /* Might as well look up the relevant <> operator while we are at it */
297 120 : typentry = lookup_type_cache(cycle_clause->cycle_mark_type,
298 : TYPECACHE_EQ_OPR);
299 120 : if (!OidIsValid(typentry->eq_opr))
300 6 : ereport(ERROR,
301 : errcode(ERRCODE_UNDEFINED_FUNCTION),
302 : errmsg("could not identify an equality operator for type %s",
303 : format_type_be(cycle_clause->cycle_mark_type)));
304 114 : op = get_negator(typentry->eq_opr);
305 114 : if (!OidIsValid(op))
306 0 : ereport(ERROR,
307 : errcode(ERRCODE_UNDEFINED_FUNCTION),
308 : errmsg("could not identify an inequality operator for type %s",
309 : format_type_be(cycle_clause->cycle_mark_type)));
310 :
311 114 : cycle_clause->cycle_mark_neop = op;
312 : }
313 :
314 : /* Now we can get on with analyzing the CTE's query */
315 4200 : query = parse_sub_analyze(cte->ctequery, pstate, cte, false, true);
316 4174 : cte->ctequery = (Node *) query;
317 :
318 : /*
319 : * Check that we got something reasonable. These first two cases should
320 : * be prevented by the grammar.
321 : */
322 4174 : if (!IsA(query, Query))
323 0 : elog(ERROR, "unexpected non-Query statement in WITH");
324 4174 : if (query->utilityStmt != NULL)
325 0 : elog(ERROR, "unexpected utility statement in WITH");
326 :
327 : /*
328 : * We disallow data-modifying WITH except at the top level of a query,
329 : * because it's not clear when such a modification should be executed.
330 : */
331 4174 : if (query->commandType != CMD_SELECT &&
332 378 : pstate->parentParseState != NULL)
333 6 : ereport(ERROR,
334 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
335 : errmsg("WITH clause containing a data-modifying statement must be at the top level"),
336 : parser_errposition(pstate, cte->location)));
337 :
338 : /*
339 : * CTE queries are always marked not canSetTag. (Currently this only
340 : * matters for data-modifying statements, for which the flag will be
341 : * propagated to the ModifyTable plan node.)
342 : */
343 4168 : query->canSetTag = false;
344 :
345 4168 : if (!cte->cterecursive)
346 : {
347 : /* Compute the output column names/types if not done yet */
348 3158 : analyzeCTETargetList(pstate, cte, GetCTETargetList(cte));
349 : }
350 : else
351 : {
352 : /*
353 : * Verify that the previously determined output column types and
354 : * collations match what the query really produced. We have to check
355 : * this because the recursive term could have overridden the
356 : * non-recursive term, and we don't have any easy way to fix that.
357 : */
358 : ListCell *lctlist,
359 : *lctyp,
360 : *lctypmod,
361 : *lccoll;
362 : int varattno;
363 :
364 1010 : lctyp = list_head(cte->ctecoltypes);
365 1010 : lctypmod = list_head(cte->ctecoltypmods);
366 1010 : lccoll = list_head(cte->ctecolcollations);
367 1010 : varattno = 0;
368 3150 : foreach(lctlist, GetCTETargetList(cte))
369 : {
370 2164 : TargetEntry *te = (TargetEntry *) lfirst(lctlist);
371 : Node *texpr;
372 :
373 2164 : if (te->resjunk)
374 0 : continue;
375 2164 : varattno++;
376 : Assert(varattno == te->resno);
377 2164 : if (lctyp == NULL || lctypmod == NULL || lccoll == NULL) /* shouldn't happen */
378 0 : elog(ERROR, "wrong number of output columns in WITH");
379 2164 : texpr = (Node *) te->expr;
380 2164 : if (exprType(texpr) != lfirst_oid(lctyp) ||
381 2158 : exprTypmod(texpr) != lfirst_int(lctypmod))
382 12 : ereport(ERROR,
383 : (errcode(ERRCODE_DATATYPE_MISMATCH),
384 : errmsg("recursive query \"%s\" column %d has type %s in non-recursive term but type %s overall",
385 : cte->ctename, varattno,
386 : format_type_with_typemod(lfirst_oid(lctyp),
387 : lfirst_int(lctypmod)),
388 : format_type_with_typemod(exprType(texpr),
389 : exprTypmod(texpr))),
390 : errhint("Cast the output of the non-recursive term to the correct type."),
391 : parser_errposition(pstate, exprLocation(texpr))));
392 2152 : if (exprCollation(texpr) != lfirst_oid(lccoll))
393 12 : ereport(ERROR,
394 : (errcode(ERRCODE_COLLATION_MISMATCH),
395 : errmsg("recursive query \"%s\" column %d has collation \"%s\" in non-recursive term but collation \"%s\" overall",
396 : cte->ctename, varattno,
397 : get_collation_name(lfirst_oid(lccoll)),
398 : get_collation_name(exprCollation(texpr))),
399 : errhint("Use the COLLATE clause to set the collation of the non-recursive term."),
400 : parser_errposition(pstate, exprLocation(texpr))));
401 2140 : lctyp = lnext(cte->ctecoltypes, lctyp);
402 2140 : lctypmod = lnext(cte->ctecoltypmods, lctypmod);
403 2140 : lccoll = lnext(cte->ctecolcollations, lccoll);
404 : }
405 986 : if (lctyp != NULL || lctypmod != NULL || lccoll != NULL) /* shouldn't happen */
406 0 : elog(ERROR, "wrong number of output columns in WITH");
407 : }
408 :
409 : /*
410 : * Now make validity checks on the SEARCH and CYCLE clauses, if present.
411 : */
412 4138 : if (search_clause || cycle_clause)
413 : {
414 : Query *ctequery;
415 : SetOperationStmt *sos;
416 :
417 216 : if (!cte->cterecursive)
418 0 : ereport(ERROR,
419 : (errcode(ERRCODE_SYNTAX_ERROR),
420 : errmsg("WITH query is not recursive"),
421 : parser_errposition(pstate, cte->location)));
422 :
423 : /*
424 : * SQL requires a WITH list element (CTE) to be "expandable" in order
425 : * to allow a search or cycle clause. That is a stronger requirement
426 : * than just being recursive. It basically means the query expression
427 : * looks like
428 : *
429 : * non-recursive query UNION [ALL] recursive query
430 : *
431 : * and that the recursive query is not itself a set operation.
432 : *
433 : * As of this writing, most of these criteria are already satisfied by
434 : * all recursive CTEs allowed by PostgreSQL. In the future, if
435 : * further variants recursive CTEs are accepted, there might be
436 : * further checks required here to determine what is "expandable".
437 : */
438 :
439 216 : ctequery = castNode(Query, cte->ctequery);
440 : Assert(ctequery->setOperations);
441 216 : sos = castNode(SetOperationStmt, ctequery->setOperations);
442 :
443 : /*
444 : * This left side check is not required for expandability, but
445 : * rewriteSearchAndCycle() doesn't currently have support for it, so
446 : * we catch it here.
447 : */
448 216 : if (!IsA(sos->larg, RangeTblRef))
449 6 : ereport(ERROR,
450 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
451 : errmsg("with a SEARCH or CYCLE clause, the left side of the UNION must be a SELECT")));
452 :
453 210 : if (!IsA(sos->rarg, RangeTblRef))
454 6 : ereport(ERROR,
455 : (errcode(ERRCODE_SYNTAX_ERROR),
456 : errmsg("with a SEARCH or CYCLE clause, the right side of the UNION must be a SELECT")));
457 : }
458 :
459 4126 : if (search_clause)
460 : {
461 : ListCell *lc;
462 114 : List *seen = NIL;
463 :
464 300 : foreach(lc, search_clause->search_col_list)
465 : {
466 198 : String *colname = lfirst_node(String, lc);
467 :
468 198 : if (!list_member(cte->ctecolnames, colname))
469 6 : ereport(ERROR,
470 : (errcode(ERRCODE_SYNTAX_ERROR),
471 : errmsg("search column \"%s\" not in WITH query column list",
472 : strVal(colname)),
473 : parser_errposition(pstate, search_clause->location)));
474 :
475 192 : if (list_member(seen, colname))
476 6 : ereport(ERROR,
477 : (errcode(ERRCODE_DUPLICATE_COLUMN),
478 : errmsg("search column \"%s\" specified more than once",
479 : strVal(colname)),
480 : parser_errposition(pstate, search_clause->location)));
481 186 : seen = lappend(seen, colname);
482 : }
483 :
484 102 : if (list_member(cte->ctecolnames, makeString(search_clause->search_seq_column)))
485 6 : ereport(ERROR,
486 : errcode(ERRCODE_SYNTAX_ERROR),
487 : errmsg("search sequence column name \"%s\" already used in WITH query column list",
488 : search_clause->search_seq_column),
489 : parser_errposition(pstate, search_clause->location));
490 : }
491 :
492 4108 : if (cycle_clause)
493 : {
494 : ListCell *lc;
495 114 : List *seen = NIL;
496 :
497 306 : foreach(lc, cycle_clause->cycle_col_list)
498 : {
499 204 : String *colname = lfirst_node(String, lc);
500 :
501 204 : if (!list_member(cte->ctecolnames, colname))
502 6 : ereport(ERROR,
503 : (errcode(ERRCODE_SYNTAX_ERROR),
504 : errmsg("cycle column \"%s\" not in WITH query column list",
505 : strVal(colname)),
506 : parser_errposition(pstate, cycle_clause->location)));
507 :
508 198 : if (list_member(seen, colname))
509 6 : ereport(ERROR,
510 : (errcode(ERRCODE_DUPLICATE_COLUMN),
511 : errmsg("cycle column \"%s\" specified more than once",
512 : strVal(colname)),
513 : parser_errposition(pstate, cycle_clause->location)));
514 192 : seen = lappend(seen, colname);
515 : }
516 :
517 102 : if (list_member(cte->ctecolnames, makeString(cycle_clause->cycle_mark_column)))
518 6 : ereport(ERROR,
519 : errcode(ERRCODE_SYNTAX_ERROR),
520 : errmsg("cycle mark column name \"%s\" already used in WITH query column list",
521 : cycle_clause->cycle_mark_column),
522 : parser_errposition(pstate, cycle_clause->location));
523 :
524 96 : if (list_member(cte->ctecolnames, makeString(cycle_clause->cycle_path_column)))
525 6 : ereport(ERROR,
526 : errcode(ERRCODE_SYNTAX_ERROR),
527 : errmsg("cycle path column name \"%s\" already used in WITH query column list",
528 : cycle_clause->cycle_path_column),
529 : parser_errposition(pstate, cycle_clause->location));
530 :
531 90 : if (strcmp(cycle_clause->cycle_mark_column,
532 90 : cycle_clause->cycle_path_column) == 0)
533 6 : ereport(ERROR,
534 : errcode(ERRCODE_SYNTAX_ERROR),
535 : errmsg("cycle mark column name and cycle path column name are the same"),
536 : parser_errposition(pstate, cycle_clause->location));
537 : }
538 :
539 4078 : if (search_clause && cycle_clause)
540 : {
541 24 : if (strcmp(search_clause->search_seq_column,
542 24 : cycle_clause->cycle_mark_column) == 0)
543 6 : ereport(ERROR,
544 : errcode(ERRCODE_SYNTAX_ERROR),
545 : errmsg("search sequence column name and cycle mark column name are the same"),
546 : parser_errposition(pstate, search_clause->location));
547 :
548 18 : if (strcmp(search_clause->search_seq_column,
549 18 : cycle_clause->cycle_path_column) == 0)
550 6 : ereport(ERROR,
551 : errcode(ERRCODE_SYNTAX_ERROR),
552 : errmsg("search sequence column name and cycle path column name are the same"),
553 : parser_errposition(pstate, search_clause->location));
554 : }
555 4066 : }
556 :
557 : /*
558 : * Compute derived fields of a CTE, given the transformed output targetlist
559 : *
560 : * For a nonrecursive CTE, this is called after transforming the CTE's query.
561 : * For a recursive CTE, we call it after transforming the non-recursive term,
562 : * and pass the targetlist emitted by the non-recursive term only.
563 : *
564 : * Note: in the recursive case, the passed pstate is actually the one being
565 : * used to analyze the CTE's query, so it is one level lower down than in
566 : * the nonrecursive case. This doesn't matter since we only use it for
567 : * error message context anyway.
568 : */
569 : void
570 4186 : analyzeCTETargetList(ParseState *pstate, CommonTableExpr *cte, List *tlist)
571 : {
572 : int numaliases;
573 : int varattno;
574 : ListCell *tlistitem;
575 :
576 : /* Not done already ... */
577 : Assert(cte->ctecolnames == NIL);
578 :
579 : /*
580 : * We need to determine column names, types, and collations. The alias
581 : * column names override anything coming from the query itself. (Note:
582 : * the SQL spec says that the alias list must be empty or exactly as long
583 : * as the output column set; but we allow it to be shorter for consistency
584 : * with Alias handling.)
585 : */
586 4186 : cte->ctecolnames = copyObject(cte->aliascolnames);
587 4186 : cte->ctecoltypes = cte->ctecoltypmods = cte->ctecolcollations = NIL;
588 4186 : numaliases = list_length(cte->aliascolnames);
589 4186 : varattno = 0;
590 14112 : foreach(tlistitem, tlist)
591 : {
592 9926 : TargetEntry *te = (TargetEntry *) lfirst(tlistitem);
593 : Oid coltype;
594 : int32 coltypmod;
595 : Oid colcoll;
596 :
597 9926 : if (te->resjunk)
598 6 : continue;
599 9920 : varattno++;
600 : Assert(varattno == te->resno);
601 9920 : if (varattno > numaliases)
602 : {
603 : char *attrname;
604 :
605 3884 : attrname = pstrdup(te->resname);
606 3884 : cte->ctecolnames = lappend(cte->ctecolnames, makeString(attrname));
607 : }
608 9920 : coltype = exprType((Node *) te->expr);
609 9920 : coltypmod = exprTypmod((Node *) te->expr);
610 9920 : colcoll = exprCollation((Node *) te->expr);
611 :
612 : /*
613 : * If the CTE is recursive, force the exposed column type of any
614 : * "unknown" column to "text". We must deal with this here because
615 : * we're called on the non-recursive term before there's been any
616 : * attempt to force unknown output columns to some other type. We
617 : * have to resolve unknowns before looking at the recursive term.
618 : *
619 : * The column might contain 'foo' COLLATE "bar", so don't override
620 : * collation if it's already set.
621 : */
622 9920 : if (cte->cterecursive && coltype == UNKNOWNOID)
623 : {
624 36 : coltype = TEXTOID;
625 36 : coltypmod = -1; /* should be -1 already, but be sure */
626 36 : if (!OidIsValid(colcoll))
627 36 : colcoll = DEFAULT_COLLATION_OID;
628 : }
629 9920 : cte->ctecoltypes = lappend_oid(cte->ctecoltypes, coltype);
630 9920 : cte->ctecoltypmods = lappend_int(cte->ctecoltypmods, coltypmod);
631 9920 : cte->ctecolcollations = lappend_oid(cte->ctecolcollations, colcoll);
632 : }
633 4186 : if (varattno < numaliases)
634 6 : ereport(ERROR,
635 : (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
636 : errmsg("WITH query \"%s\" has %d columns available but %d columns specified",
637 : cte->ctename, varattno, numaliases),
638 : parser_errposition(pstate, cte->location)));
639 4180 : }
640 :
641 :
642 : /*
643 : * Identify the cross-references of a list of WITH RECURSIVE items,
644 : * and sort into an order that has no forward references.
645 : */
646 : static void
647 1214 : makeDependencyGraph(CteState *cstate)
648 : {
649 : int i;
650 :
651 2524 : for (i = 0; i < cstate->numitems; i++)
652 : {
653 1310 : CommonTableExpr *cte = cstate->items[i].cte;
654 :
655 1310 : cstate->curitem = i;
656 1310 : cstate->innerwiths = NIL;
657 1310 : makeDependencyGraphWalker((Node *) cte->ctequery, cstate);
658 : Assert(cstate->innerwiths == NIL);
659 : }
660 :
661 1214 : TopologicalSort(cstate->pstate, cstate->items, cstate->numitems);
662 1208 : }
663 :
664 : /*
665 : * Tree walker function to detect cross-references and self-references of the
666 : * CTEs in a WITH RECURSIVE list.
667 : */
668 : static bool
669 149902 : makeDependencyGraphWalker(Node *node, CteState *cstate)
670 : {
671 149902 : if (node == NULL)
672 85108 : return false;
673 64794 : if (IsA(node, RangeVar))
674 : {
675 6404 : RangeVar *rv = (RangeVar *) node;
676 :
677 : /* If unqualified name, might be a CTE reference */
678 6404 : if (!rv->schemaname)
679 : {
680 : ListCell *lc;
681 : int i;
682 :
683 : /* ... but first see if it's captured by an inner WITH */
684 5310 : foreach(lc, cstate->innerwiths)
685 : {
686 1106 : List *withlist = (List *) lfirst(lc);
687 : ListCell *lc2;
688 :
689 1214 : foreach(lc2, withlist)
690 : {
691 940 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc2);
692 :
693 940 : if (strcmp(rv->relname, cte->ctename) == 0)
694 832 : return false; /* yes, so bail out */
695 : }
696 : }
697 :
698 : /* No, could be a reference to the query level we are working on */
699 7194 : for (i = 0; i < cstate->numitems; i++)
700 : {
701 4342 : CommonTableExpr *cte = cstate->items[i].cte;
702 :
703 4342 : if (strcmp(rv->relname, cte->ctename) == 0)
704 : {
705 1352 : int myindex = cstate->curitem;
706 :
707 1352 : if (i != myindex)
708 : {
709 : /* Add cross-item dependency */
710 126 : cstate->items[myindex].depends_on =
711 126 : bms_add_member(cstate->items[myindex].depends_on,
712 126 : cstate->items[i].id);
713 : }
714 : else
715 : {
716 : /* Found out this one is self-referential */
717 1226 : cte->cterecursive = true;
718 : }
719 1352 : break;
720 : }
721 : }
722 : }
723 5572 : return false;
724 : }
725 58390 : if (IsA(node, SelectStmt))
726 : {
727 5488 : SelectStmt *stmt = (SelectStmt *) node;
728 : ListCell *lc;
729 :
730 5488 : if (stmt->withClause)
731 : {
732 328 : if (stmt->withClause->recursive)
733 : {
734 : /*
735 : * In the RECURSIVE case, all query names of the WITH are
736 : * visible to all WITH items as well as the main query. So
737 : * push them all on, process, pop them all off.
738 : */
739 18 : cstate->innerwiths = lcons(stmt->withClause->ctes,
740 : cstate->innerwiths);
741 36 : foreach(lc, stmt->withClause->ctes)
742 : {
743 18 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
744 :
745 18 : (void) makeDependencyGraphWalker(cte->ctequery, cstate);
746 : }
747 18 : (void) raw_expression_tree_walker(node,
748 : makeDependencyGraphWalker,
749 : cstate);
750 18 : cstate->innerwiths = list_delete_first(cstate->innerwiths);
751 : }
752 : else
753 : {
754 : /*
755 : * In the non-RECURSIVE case, query names are visible to the
756 : * WITH items after them and to the main query.
757 : */
758 310 : cstate->innerwiths = lcons(NIL, cstate->innerwiths);
759 644 : foreach(lc, stmt->withClause->ctes)
760 : {
761 334 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
762 : ListCell *cell1;
763 :
764 334 : (void) makeDependencyGraphWalker(cte->ctequery, cstate);
765 : /* note that recursion could mutate innerwiths list */
766 334 : cell1 = list_head(cstate->innerwiths);
767 334 : lfirst(cell1) = lappend((List *) lfirst(cell1), cte);
768 : }
769 310 : (void) raw_expression_tree_walker(node,
770 : makeDependencyGraphWalker,
771 : cstate);
772 310 : cstate->innerwiths = list_delete_first(cstate->innerwiths);
773 : }
774 : /* We're done examining the SelectStmt */
775 328 : return false;
776 : }
777 : /* if no WITH clause, just fall through for normal processing */
778 : }
779 58062 : if (IsA(node, WithClause))
780 : {
781 : /*
782 : * Prevent raw_expression_tree_walker from recursing directly into a
783 : * WITH clause. We need that to happen only under the control of the
784 : * code above.
785 : */
786 328 : return false;
787 : }
788 57734 : return raw_expression_tree_walker(node,
789 : makeDependencyGraphWalker,
790 : cstate);
791 : }
792 :
793 : /*
794 : * Sort by dependencies, using a standard topological sort operation
795 : */
796 : static void
797 1214 : TopologicalSort(ParseState *pstate, CteItem *items, int numitems)
798 : {
799 : int i,
800 : j;
801 :
802 : /* for each position in sequence ... */
803 2512 : for (i = 0; i < numitems; i++)
804 : {
805 : /* ... scan the remaining items to find one that has no dependencies */
806 1334 : for (j = i; j < numitems; j++)
807 : {
808 1328 : if (bms_is_empty(items[j].depends_on))
809 1298 : break;
810 : }
811 :
812 : /* if we didn't find one, the dependency graph has a cycle */
813 1304 : if (j >= numitems)
814 6 : ereport(ERROR,
815 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
816 : errmsg("mutual recursion between WITH items is not implemented"),
817 : parser_errposition(pstate, items[i].cte->location)));
818 :
819 : /*
820 : * Found one. Move it to front and remove it from every other item's
821 : * dependencies.
822 : */
823 1298 : if (i != j)
824 : {
825 : CteItem tmp;
826 :
827 18 : tmp = items[i];
828 18 : items[i] = items[j];
829 18 : items[j] = tmp;
830 : }
831 :
832 : /*
833 : * Items up through i are known to have no dependencies left, so we
834 : * can skip them in this loop.
835 : */
836 1400 : for (j = i + 1; j < numitems; j++)
837 : {
838 102 : items[j].depends_on = bms_del_member(items[j].depends_on,
839 102 : items[i].id);
840 : }
841 : }
842 1208 : }
843 :
844 :
845 : /*
846 : * Check that recursive queries are well-formed.
847 : */
848 : static void
849 1208 : checkWellFormedRecursion(CteState *cstate)
850 : {
851 : int i;
852 :
853 2362 : for (i = 0; i < cstate->numitems; i++)
854 : {
855 1298 : CommonTableExpr *cte = cstate->items[i].cte;
856 1298 : SelectStmt *stmt = (SelectStmt *) cte->ctequery;
857 :
858 : Assert(!IsA(stmt, Query)); /* not analyzed yet */
859 :
860 : /* Ignore items that weren't found to be recursive */
861 1298 : if (!cte->cterecursive)
862 114 : continue;
863 :
864 : /* Must be a SELECT statement */
865 1184 : if (!IsA(stmt, SelectStmt))
866 12 : ereport(ERROR,
867 : (errcode(ERRCODE_INVALID_RECURSION),
868 : errmsg("recursive query \"%s\" must not contain data-modifying statements",
869 : cte->ctename),
870 : parser_errposition(cstate->pstate, cte->location)));
871 :
872 : /* Must have top-level UNION */
873 1172 : if (stmt->op != SETOP_UNION)
874 30 : ereport(ERROR,
875 : (errcode(ERRCODE_INVALID_RECURSION),
876 : errmsg("recursive query \"%s\" does not have the form non-recursive-term UNION [ALL] recursive-term",
877 : cte->ctename),
878 : parser_errposition(cstate->pstate, cte->location)));
879 :
880 : /*
881 : * Really, we should insist that there not be a top-level WITH, since
882 : * syntactically that would enclose the UNION. However, we've not
883 : * done so in the past and it's probably too late to change. Settle
884 : * for insisting that WITH not contain a self-reference. Test this
885 : * before examining the UNION arms, to avoid issuing confusing errors
886 : * in such cases.
887 : */
888 1142 : if (stmt->withClause)
889 : {
890 18 : cstate->curitem = i;
891 18 : cstate->innerwiths = NIL;
892 18 : cstate->selfrefcount = 0;
893 18 : cstate->context = RECURSION_SUBLINK;
894 18 : checkWellFormedRecursionWalker((Node *) stmt->withClause->ctes,
895 : cstate);
896 : Assert(cstate->innerwiths == NIL);
897 : }
898 :
899 : /*
900 : * Disallow ORDER BY and similar decoration atop the UNION. These
901 : * don't make sense because it's impossible to figure out what they
902 : * mean when we have only part of the recursive query's results. (If
903 : * we did allow them, we'd have to check for recursive references
904 : * inside these subtrees. As for WITH, we have to do this before
905 : * examining the UNION arms, to avoid issuing confusing errors if
906 : * there is a recursive reference here.)
907 : */
908 1130 : if (stmt->sortClause)
909 12 : ereport(ERROR,
910 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
911 : errmsg("ORDER BY in a recursive query is not implemented"),
912 : parser_errposition(cstate->pstate,
913 : exprLocation((Node *) stmt->sortClause))));
914 1118 : if (stmt->limitOffset)
915 6 : ereport(ERROR,
916 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
917 : errmsg("OFFSET in a recursive query is not implemented"),
918 : parser_errposition(cstate->pstate,
919 : exprLocation(stmt->limitOffset))));
920 1112 : if (stmt->limitCount)
921 0 : ereport(ERROR,
922 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
923 : errmsg("LIMIT in a recursive query is not implemented"),
924 : parser_errposition(cstate->pstate,
925 : exprLocation(stmt->limitCount))));
926 1112 : if (stmt->lockingClause)
927 6 : ereport(ERROR,
928 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
929 : errmsg("FOR UPDATE/SHARE in a recursive query is not implemented"),
930 : parser_errposition(cstate->pstate,
931 : exprLocation((Node *) stmt->lockingClause))));
932 :
933 : /*
934 : * Now we can get on with checking the UNION operands themselves.
935 : *
936 : * The left-hand operand mustn't contain a self-reference at all.
937 : */
938 1106 : cstate->curitem = i;
939 1106 : cstate->innerwiths = NIL;
940 1106 : cstate->selfrefcount = 0;
941 1106 : cstate->context = RECURSION_NONRECURSIVETERM;
942 1106 : checkWellFormedRecursionWalker((Node *) stmt->larg, cstate);
943 : Assert(cstate->innerwiths == NIL);
944 :
945 : /* Right-hand operand should contain one reference in a valid place */
946 1094 : cstate->curitem = i;
947 1094 : cstate->innerwiths = NIL;
948 1094 : cstate->selfrefcount = 0;
949 1094 : cstate->context = RECURSION_OK;
950 1094 : checkWellFormedRecursionWalker((Node *) stmt->rarg, cstate);
951 : Assert(cstate->innerwiths == NIL);
952 1040 : if (cstate->selfrefcount != 1) /* shouldn't happen */
953 0 : elog(ERROR, "missing recursive reference");
954 : }
955 1064 : }
956 :
957 : /*
958 : * Tree walker function to detect invalid self-references in a recursive query.
959 : */
960 : static bool
961 119158 : checkWellFormedRecursionWalker(Node *node, CteState *cstate)
962 : {
963 119158 : RecursionContext save_context = cstate->context;
964 :
965 119158 : if (node == NULL)
966 58848 : return false;
967 60310 : if (IsA(node, RangeVar))
968 : {
969 6098 : RangeVar *rv = (RangeVar *) node;
970 :
971 : /* If unqualified name, might be a CTE reference */
972 6098 : if (!rv->schemaname)
973 : {
974 : ListCell *lc;
975 : CommonTableExpr *mycte;
976 :
977 : /* ... but first see if it's captured by an inner WITH */
978 4980 : foreach(lc, cstate->innerwiths)
979 : {
980 992 : List *withlist = (List *) lfirst(lc);
981 : ListCell *lc2;
982 :
983 1088 : foreach(lc2, withlist)
984 : {
985 838 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc2);
986 :
987 838 : if (strcmp(rv->relname, cte->ctename) == 0)
988 742 : return false; /* yes, so bail out */
989 : }
990 : }
991 :
992 : /* No, could be a reference to the query level we are working on */
993 3988 : mycte = cstate->items[cstate->curitem].cte;
994 3988 : if (strcmp(rv->relname, mycte->ctename) == 0)
995 : {
996 : /* Found a recursive reference to the active query */
997 1148 : if (cstate->context != RECURSION_OK)
998 60 : ereport(ERROR,
999 : (errcode(ERRCODE_INVALID_RECURSION),
1000 : errmsg(recursion_errormsgs[cstate->context],
1001 : mycte->ctename),
1002 : parser_errposition(cstate->pstate,
1003 : rv->location)));
1004 : /* Count references */
1005 1088 : if (++(cstate->selfrefcount) > 1)
1006 18 : ereport(ERROR,
1007 : (errcode(ERRCODE_INVALID_RECURSION),
1008 : errmsg("recursive reference to query \"%s\" must not appear more than once",
1009 : mycte->ctename),
1010 : parser_errposition(cstate->pstate,
1011 : rv->location)));
1012 : }
1013 : }
1014 5278 : return false;
1015 : }
1016 54212 : if (IsA(node, SelectStmt))
1017 : {
1018 3908 : SelectStmt *stmt = (SelectStmt *) node;
1019 : ListCell *lc;
1020 :
1021 3908 : if (stmt->withClause)
1022 : {
1023 250 : if (stmt->withClause->recursive)
1024 : {
1025 : /*
1026 : * In the RECURSIVE case, all query names of the WITH are
1027 : * visible to all WITH items as well as the main query. So
1028 : * push them all on, process, pop them all off.
1029 : */
1030 6 : cstate->innerwiths = lcons(stmt->withClause->ctes,
1031 : cstate->innerwiths);
1032 12 : foreach(lc, stmt->withClause->ctes)
1033 : {
1034 6 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
1035 :
1036 6 : (void) checkWellFormedRecursionWalker(cte->ctequery, cstate);
1037 : }
1038 6 : checkWellFormedSelectStmt(stmt, cstate);
1039 6 : cstate->innerwiths = list_delete_first(cstate->innerwiths);
1040 : }
1041 : else
1042 : {
1043 : /*
1044 : * In the non-RECURSIVE case, query names are visible to the
1045 : * WITH items after them and to the main query.
1046 : */
1047 244 : cstate->innerwiths = lcons(NIL, cstate->innerwiths);
1048 506 : foreach(lc, stmt->withClause->ctes)
1049 : {
1050 268 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
1051 : ListCell *cell1;
1052 :
1053 268 : (void) checkWellFormedRecursionWalker(cte->ctequery, cstate);
1054 : /* note that recursion could mutate innerwiths list */
1055 262 : cell1 = list_head(cstate->innerwiths);
1056 262 : lfirst(cell1) = lappend((List *) lfirst(cell1), cte);
1057 : }
1058 238 : checkWellFormedSelectStmt(stmt, cstate);
1059 238 : cstate->innerwiths = list_delete_first(cstate->innerwiths);
1060 : }
1061 : }
1062 : else
1063 3658 : checkWellFormedSelectStmt(stmt, cstate);
1064 : /* We're done examining the SelectStmt */
1065 3782 : return false;
1066 : }
1067 50304 : if (IsA(node, WithClause))
1068 : {
1069 : /*
1070 : * Prevent raw_expression_tree_walker from recursing directly into a
1071 : * WITH clause. We need that to happen only under the control of the
1072 : * code above.
1073 : */
1074 244 : return false;
1075 : }
1076 50060 : if (IsA(node, JoinExpr))
1077 : {
1078 2142 : JoinExpr *j = (JoinExpr *) node;
1079 :
1080 2142 : switch (j->jointype)
1081 : {
1082 2038 : case JOIN_INNER:
1083 2038 : checkWellFormedRecursionWalker(j->larg, cstate);
1084 2038 : checkWellFormedRecursionWalker(j->rarg, cstate);
1085 2038 : checkWellFormedRecursionWalker(j->quals, cstate);
1086 2038 : break;
1087 92 : case JOIN_LEFT:
1088 92 : checkWellFormedRecursionWalker(j->larg, cstate);
1089 92 : if (save_context == RECURSION_OK)
1090 6 : cstate->context = RECURSION_OUTERJOIN;
1091 92 : checkWellFormedRecursionWalker(j->rarg, cstate);
1092 86 : cstate->context = save_context;
1093 86 : checkWellFormedRecursionWalker(j->quals, cstate);
1094 86 : break;
1095 6 : case JOIN_FULL:
1096 6 : if (save_context == RECURSION_OK)
1097 6 : cstate->context = RECURSION_OUTERJOIN;
1098 6 : checkWellFormedRecursionWalker(j->larg, cstate);
1099 0 : checkWellFormedRecursionWalker(j->rarg, cstate);
1100 0 : cstate->context = save_context;
1101 0 : checkWellFormedRecursionWalker(j->quals, cstate);
1102 0 : break;
1103 6 : case JOIN_RIGHT:
1104 6 : if (save_context == RECURSION_OK)
1105 6 : cstate->context = RECURSION_OUTERJOIN;
1106 6 : checkWellFormedRecursionWalker(j->larg, cstate);
1107 0 : cstate->context = save_context;
1108 0 : checkWellFormedRecursionWalker(j->rarg, cstate);
1109 0 : checkWellFormedRecursionWalker(j->quals, cstate);
1110 0 : break;
1111 0 : default:
1112 0 : elog(ERROR, "unrecognized join type: %d",
1113 : (int) j->jointype);
1114 : }
1115 2124 : return false;
1116 : }
1117 47918 : if (IsA(node, SubLink))
1118 : {
1119 92 : SubLink *sl = (SubLink *) node;
1120 :
1121 : /*
1122 : * we intentionally override outer context, since subquery is
1123 : * independent
1124 : */
1125 92 : cstate->context = RECURSION_SUBLINK;
1126 92 : checkWellFormedRecursionWalker(sl->subselect, cstate);
1127 80 : cstate->context = save_context;
1128 80 : checkWellFormedRecursionWalker(sl->testexpr, cstate);
1129 80 : return false;
1130 : }
1131 47826 : return raw_expression_tree_walker(node,
1132 : checkWellFormedRecursionWalker,
1133 : cstate);
1134 : }
1135 :
1136 : /*
1137 : * subroutine for checkWellFormedRecursionWalker: process a SelectStmt
1138 : * without worrying about its WITH clause
1139 : */
1140 : static void
1141 3902 : checkWellFormedSelectStmt(SelectStmt *stmt, CteState *cstate)
1142 : {
1143 3902 : RecursionContext save_context = cstate->context;
1144 :
1145 3902 : if (save_context != RECURSION_OK)
1146 : {
1147 : /* just recurse without changing state */
1148 1282 : raw_expression_tree_walker((Node *) stmt,
1149 : checkWellFormedRecursionWalker,
1150 : cstate);
1151 : }
1152 : else
1153 : {
1154 2620 : switch (stmt->op)
1155 : {
1156 2608 : case SETOP_NONE:
1157 : case SETOP_UNION:
1158 2608 : raw_expression_tree_walker((Node *) stmt,
1159 : checkWellFormedRecursionWalker,
1160 : cstate);
1161 2542 : break;
1162 6 : case SETOP_INTERSECT:
1163 6 : if (stmt->all)
1164 0 : cstate->context = RECURSION_INTERSECT;
1165 6 : checkWellFormedRecursionWalker((Node *) stmt->larg,
1166 : cstate);
1167 6 : checkWellFormedRecursionWalker((Node *) stmt->rarg,
1168 : cstate);
1169 0 : cstate->context = save_context;
1170 0 : checkWellFormedRecursionWalker((Node *) stmt->sortClause,
1171 : cstate);
1172 0 : checkWellFormedRecursionWalker((Node *) stmt->limitOffset,
1173 : cstate);
1174 0 : checkWellFormedRecursionWalker((Node *) stmt->limitCount,
1175 : cstate);
1176 0 : checkWellFormedRecursionWalker((Node *) stmt->lockingClause,
1177 : cstate);
1178 : /* stmt->withClause is intentionally ignored here */
1179 0 : break;
1180 6 : case SETOP_EXCEPT:
1181 6 : if (stmt->all)
1182 0 : cstate->context = RECURSION_EXCEPT;
1183 6 : checkWellFormedRecursionWalker((Node *) stmt->larg,
1184 : cstate);
1185 6 : cstate->context = RECURSION_EXCEPT;
1186 6 : checkWellFormedRecursionWalker((Node *) stmt->rarg,
1187 : cstate);
1188 0 : cstate->context = save_context;
1189 0 : checkWellFormedRecursionWalker((Node *) stmt->sortClause,
1190 : cstate);
1191 0 : checkWellFormedRecursionWalker((Node *) stmt->limitOffset,
1192 : cstate);
1193 0 : checkWellFormedRecursionWalker((Node *) stmt->limitCount,
1194 : cstate);
1195 0 : checkWellFormedRecursionWalker((Node *) stmt->lockingClause,
1196 : cstate);
1197 : /* stmt->withClause is intentionally ignored here */
1198 0 : break;
1199 0 : default:
1200 0 : elog(ERROR, "unrecognized set op: %d",
1201 : (int) stmt->op);
1202 : }
1203 : }
1204 3782 : }
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