Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * preptlist.c
4 : * Routines to preprocess the parse tree target list
5 : *
6 : * For an INSERT, the targetlist must contain an entry for each attribute of
7 : * the target relation in the correct order.
8 : *
9 : * For an UPDATE, the targetlist just contains the expressions for the new
10 : * column values.
11 : *
12 : * For UPDATE and DELETE queries, the targetlist must also contain "junk"
13 : * tlist entries needed to allow the executor to identify the rows to be
14 : * updated or deleted; for example, the ctid of a heap row. (The planner
15 : * adds these; they're not in what we receive from the parser/rewriter.)
16 : *
17 : * For all query types, there can be additional junk tlist entries, such as
18 : * sort keys, Vars needed for a RETURNING list, and row ID information needed
19 : * for SELECT FOR UPDATE locking and/or EvalPlanQual checking.
20 : *
21 : * The query rewrite phase also does preprocessing of the targetlist (see
22 : * rewriteTargetListIU). The division of labor between here and there is
23 : * partially historical, but it's not entirely arbitrary. The stuff done
24 : * here is closely connected to physical access to tables, whereas the
25 : * rewriter's work is more concerned with SQL semantics.
26 : *
27 : *
28 : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
29 : * Portions Copyright (c) 1994, Regents of the University of California
30 : *
31 : * IDENTIFICATION
32 : * src/backend/optimizer/prep/preptlist.c
33 : *
34 : *-------------------------------------------------------------------------
35 : */
36 :
37 : #include "postgres.h"
38 :
39 : #include "access/sysattr.h"
40 : #include "access/table.h"
41 : #include "catalog/pg_type_d.h"
42 : #include "nodes/makefuncs.h"
43 : #include "optimizer/appendinfo.h"
44 : #include "optimizer/optimizer.h"
45 : #include "optimizer/prep.h"
46 : #include "optimizer/tlist.h"
47 : #include "parser/parse_coerce.h"
48 : #include "parser/parsetree.h"
49 : #include "utils/lsyscache.h"
50 : #include "utils/rel.h"
51 :
52 : static List *expand_insert_targetlist(PlannerInfo *root, List *tlist,
53 : Relation rel);
54 :
55 :
56 : /*
57 : * preprocess_targetlist
58 : * Driver for preprocessing the parse tree targetlist.
59 : *
60 : * The preprocessed targetlist is returned in root->processed_tlist.
61 : * Also, if this is an UPDATE, we return a list of target column numbers
62 : * in root->update_colnos. (Resnos in processed_tlist will be consecutive,
63 : * so do not look at that to find out which columns are targets!)
64 : */
65 : void
66 388653 : preprocess_targetlist(PlannerInfo *root)
67 : {
68 388653 : Query *parse = root->parse;
69 388653 : int result_relation = parse->resultRelation;
70 388653 : List *range_table = parse->rtable;
71 388653 : CmdType command_type = parse->commandType;
72 388653 : RangeTblEntry *target_rte = NULL;
73 388653 : Relation target_relation = NULL;
74 : List *tlist;
75 : ListCell *lc;
76 :
77 : /*
78 : * If there is a result relation, open it so we can look for missing
79 : * columns and so on. We assume that previous code already acquired at
80 : * least AccessShareLock on the relation, so we need no lock here.
81 : */
82 388653 : if (result_relation)
83 : {
84 62838 : target_rte = rt_fetch(result_relation, range_table);
85 :
86 : /*
87 : * Sanity check: it'd better be a real relation not, say, a subquery.
88 : * Else parser or rewriter messed up.
89 : */
90 62838 : if (target_rte->rtekind != RTE_RELATION)
91 0 : elog(ERROR, "result relation must be a regular relation");
92 :
93 62838 : target_relation = table_open(target_rte->relid, NoLock);
94 : }
95 : else
96 : Assert(command_type == CMD_SELECT);
97 :
98 : /*
99 : * In an INSERT, the executor expects the targetlist to match the exact
100 : * order of the target table's attributes, including entries for
101 : * attributes not mentioned in the source query.
102 : *
103 : * In an UPDATE, we don't rearrange the tlist order, but we need to make a
104 : * separate list of the target attribute numbers, in tlist order, and then
105 : * renumber the processed_tlist entries to be consecutive.
106 : */
107 388653 : tlist = parse->targetList;
108 388653 : if (command_type == CMD_INSERT)
109 48401 : tlist = expand_insert_targetlist(root, tlist, target_relation);
110 340252 : else if (command_type == CMD_UPDATE)
111 9728 : root->update_colnos = extract_update_targetlist_colnos(tlist);
112 :
113 : /*
114 : * For non-inherited UPDATE/DELETE/MERGE, register any junk column(s)
115 : * needed to allow the executor to identify the rows to be updated or
116 : * deleted. In the inheritance case, we do nothing now, leaving this to
117 : * be dealt with when expand_inherited_rtentry() makes the leaf target
118 : * relations. (But there might not be any leaf target relations, in which
119 : * case we must do this in distribute_row_identity_vars().)
120 : */
121 388653 : if ((command_type == CMD_UPDATE || command_type == CMD_DELETE ||
122 14437 : command_type == CMD_MERGE) &&
123 14437 : !target_rte->inh)
124 : {
125 : /* row-identity logic expects to add stuff to processed_tlist */
126 12191 : root->processed_tlist = tlist;
127 12191 : add_row_identity_columns(root, result_relation,
128 : target_rte, target_relation);
129 12191 : tlist = root->processed_tlist;
130 : }
131 :
132 : /*
133 : * For MERGE we also need to handle the target list for each INSERT and
134 : * UPDATE action separately. In addition, we examine the qual of each
135 : * action and add any Vars there (other than those of the target rel) to
136 : * the subplan targetlist.
137 : */
138 388653 : if (command_type == CMD_MERGE)
139 : {
140 : ListCell *l;
141 : List *vars;
142 :
143 : /*
144 : * For MERGE, handle targetlist of each MergeAction separately. Give
145 : * the same treatment to MergeAction->targetList as we would have
146 : * given to a regular INSERT. For UPDATE, collect the column numbers
147 : * being modified.
148 : */
149 3731 : foreach(l, parse->mergeActionList)
150 : {
151 2256 : MergeAction *action = (MergeAction *) lfirst(l);
152 : ListCell *l2;
153 :
154 2256 : if (action->commandType == CMD_INSERT)
155 741 : action->targetList = expand_insert_targetlist(root,
156 : action->targetList,
157 : target_relation);
158 1515 : else if (action->commandType == CMD_UPDATE)
159 1067 : action->updateColnos =
160 1067 : extract_update_targetlist_colnos(action->targetList);
161 :
162 : /*
163 : * Add resjunk entries for any Vars and PlaceHolderVars used in
164 : * each action's targetlist and WHEN condition that belong to
165 : * relations other than the target. We don't expect to see any
166 : * aggregates or window functions here.
167 : */
168 2256 : vars = pull_var_clause((Node *)
169 2256 : list_concat_copy((List *) action->qual,
170 2256 : action->targetList),
171 : PVC_INCLUDE_PLACEHOLDERS);
172 5050 : foreach(l2, vars)
173 : {
174 2794 : Var *var = (Var *) lfirst(l2);
175 : TargetEntry *tle;
176 :
177 2794 : if (IsA(var, Var) && var->varno == result_relation)
178 1330 : continue; /* don't need it */
179 :
180 1464 : if (tlist_member((Expr *) var, tlist))
181 389 : continue; /* already got it */
182 :
183 1075 : tle = makeTargetEntry((Expr *) var,
184 1075 : list_length(tlist) + 1,
185 : NULL, true);
186 1075 : tlist = lappend(tlist, tle);
187 : }
188 2256 : list_free(vars);
189 : }
190 :
191 : /*
192 : * Add resjunk entries for any Vars and PlaceHolderVars used in the
193 : * join condition that belong to relations other than the target. We
194 : * don't expect to see any aggregates or window functions here.
195 : */
196 1475 : vars = pull_var_clause(parse->mergeJoinCondition,
197 : PVC_INCLUDE_PLACEHOLDERS);
198 1800 : foreach(l, vars)
199 : {
200 325 : Var *var = (Var *) lfirst(l);
201 : TargetEntry *tle;
202 :
203 325 : if (IsA(var, Var) && var->varno == result_relation)
204 110 : continue; /* don't need it */
205 :
206 215 : if (tlist_member((Expr *) var, tlist))
207 85 : continue; /* already got it */
208 :
209 130 : tle = makeTargetEntry((Expr *) var,
210 130 : list_length(tlist) + 1,
211 : NULL, true);
212 130 : tlist = lappend(tlist, tle);
213 : }
214 : }
215 :
216 : /*
217 : * Add necessary junk columns for rowmarked rels. These values are needed
218 : * for locking of rels selected FOR UPDATE/SHARE, and to do EvalPlanQual
219 : * rechecking. See comments for PlanRowMark in plannodes.h. If you
220 : * change this stanza, see also expand_inherited_rtentry(), which has to
221 : * be able to add on junk columns equivalent to these.
222 : *
223 : * (Someday it might be useful to fold these resjunk columns into the
224 : * row-identity-column management used for UPDATE/DELETE. Today is not
225 : * that day, however. One notable issue is that it seems important that
226 : * the whole-row Vars made here use the real table rowtype, not RECORD, so
227 : * that conversion to/from child relations' rowtypes will happen. Also,
228 : * since these entries don't potentially bloat with more and more child
229 : * relations, there's not really much need for column sharing.)
230 : */
231 399525 : foreach(lc, root->rowMarks)
232 : {
233 10872 : PlanRowMark *rc = (PlanRowMark *) lfirst(lc);
234 : Var *var;
235 : char resname[32];
236 : TargetEntry *tle;
237 :
238 : /* child rels use the same junk attrs as their parents */
239 10872 : if (rc->rti != rc->prti)
240 0 : continue;
241 :
242 10872 : if (rc->allMarkTypes & ~(1 << ROW_MARK_COPY))
243 : {
244 : /* Need to fetch TID */
245 10344 : var = makeVar(rc->rti,
246 : SelfItemPointerAttributeNumber,
247 : TIDOID,
248 : -1,
249 : InvalidOid,
250 : 0);
251 10344 : snprintf(resname, sizeof(resname), "ctid%u", rc->rowmarkId);
252 10344 : tle = makeTargetEntry((Expr *) var,
253 10344 : list_length(tlist) + 1,
254 : pstrdup(resname),
255 : true);
256 10344 : tlist = lappend(tlist, tle);
257 : }
258 10872 : if (rc->allMarkTypes & (1 << ROW_MARK_COPY))
259 : {
260 : /* Need the whole row as a junk var */
261 528 : var = makeWholeRowVar(rt_fetch(rc->rti, range_table),
262 528 : rc->rti,
263 : 0,
264 : false);
265 528 : snprintf(resname, sizeof(resname), "wholerow%u", rc->rowmarkId);
266 528 : tle = makeTargetEntry((Expr *) var,
267 528 : list_length(tlist) + 1,
268 : pstrdup(resname),
269 : true);
270 528 : tlist = lappend(tlist, tle);
271 : }
272 :
273 : /* If parent of inheritance tree, always fetch the tableoid too. */
274 10872 : if (rc->isParent)
275 : {
276 0 : var = makeVar(rc->rti,
277 : TableOidAttributeNumber,
278 : OIDOID,
279 : -1,
280 : InvalidOid,
281 : 0);
282 0 : snprintf(resname, sizeof(resname), "tableoid%u", rc->rowmarkId);
283 0 : tle = makeTargetEntry((Expr *) var,
284 0 : list_length(tlist) + 1,
285 : pstrdup(resname),
286 : true);
287 0 : tlist = lappend(tlist, tle);
288 : }
289 : }
290 :
291 : /*
292 : * If the query has a RETURNING list, add resjunk entries for any Vars
293 : * used in RETURNING that belong to other relations. We need to do this
294 : * to make these Vars available for the RETURNING calculation. Vars that
295 : * belong to the result rel don't need to be added, because they will be
296 : * made to refer to the actual heap tuple.
297 : */
298 388653 : if (parse->returningList && list_length(parse->rtable) > 1)
299 : {
300 : List *vars;
301 : ListCell *l;
302 :
303 1716 : vars = pull_var_clause((Node *) parse->returningList,
304 : PVC_RECURSE_AGGREGATES |
305 : PVC_RECURSE_WINDOWFUNCS |
306 : PVC_INCLUDE_PLACEHOLDERS);
307 7480 : foreach(l, vars)
308 : {
309 5764 : Var *var = (Var *) lfirst(l);
310 : TargetEntry *tle;
311 :
312 5764 : if (IsA(var, Var) &&
313 5764 : var->varno == result_relation)
314 5252 : continue; /* don't need it */
315 :
316 512 : if (tlist_member((Expr *) var, tlist))
317 192 : continue; /* already got it */
318 :
319 320 : tle = makeTargetEntry((Expr *) var,
320 320 : list_length(tlist) + 1,
321 : NULL,
322 : true);
323 :
324 320 : tlist = lappend(tlist, tle);
325 : }
326 1716 : list_free(vars);
327 : }
328 :
329 388653 : root->processed_tlist = tlist;
330 :
331 388653 : if (target_relation)
332 62838 : table_close(target_relation, NoLock);
333 388653 : }
334 :
335 : /*
336 : * extract_update_targetlist_colnos
337 : * Extract a list of the target-table column numbers that
338 : * an UPDATE's targetlist wants to assign to, then renumber.
339 : *
340 : * The convention in the parser and rewriter is that the resnos in an
341 : * UPDATE's non-resjunk TLE entries are the target column numbers
342 : * to assign to. Here, we extract that info into a separate list, and
343 : * then convert the tlist to the sequential-numbering convention that's
344 : * used by all other query types.
345 : *
346 : * This is also applied to the tlist associated with INSERT ... ON CONFLICT
347 : * ... UPDATE, although not till much later in planning.
348 : */
349 : List *
350 12559 : extract_update_targetlist_colnos(List *tlist)
351 : {
352 12559 : List *update_colnos = NIL;
353 12559 : AttrNumber nextresno = 1;
354 : ListCell *lc;
355 :
356 27581 : foreach(lc, tlist)
357 : {
358 15022 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
359 :
360 15022 : if (!tle->resjunk)
361 14786 : update_colnos = lappend_int(update_colnos, tle->resno);
362 15022 : tle->resno = nextresno++;
363 : }
364 12559 : return update_colnos;
365 : }
366 :
367 :
368 : /*****************************************************************************
369 : *
370 : * TARGETLIST EXPANSION
371 : *
372 : *****************************************************************************/
373 :
374 : /*
375 : * expand_insert_targetlist
376 : * Given a target list as generated by the parser and a result relation,
377 : * add targetlist entries for any missing attributes, and ensure the
378 : * non-junk attributes appear in proper field order.
379 : *
380 : * Once upon a time we also did more or less this with UPDATE targetlists,
381 : * but now this code is only applied to INSERT targetlists.
382 : */
383 : static List *
384 49142 : expand_insert_targetlist(PlannerInfo *root, List *tlist, Relation rel)
385 : {
386 49142 : List *new_tlist = NIL;
387 : ListCell *tlist_item;
388 : int attrno,
389 : numattrs;
390 :
391 49142 : tlist_item = list_head(tlist);
392 :
393 : /*
394 : * The rewriter should have already ensured that the TLEs are in correct
395 : * order; but we have to insert TLEs for any missing attributes.
396 : *
397 : * Scan the tuple description in the relation's relcache entry to make
398 : * sure we have all the user attributes in the right order.
399 : */
400 49142 : numattrs = RelationGetNumberOfAttributes(rel);
401 :
402 163694 : for (attrno = 1; attrno <= numattrs; attrno++)
403 : {
404 114552 : Form_pg_attribute att_tup = TupleDescAttr(rel->rd_att, attrno - 1);
405 114552 : TargetEntry *new_tle = NULL;
406 :
407 114552 : if (tlist_item != NULL)
408 : {
409 107926 : TargetEntry *old_tle = (TargetEntry *) lfirst(tlist_item);
410 :
411 107926 : if (!old_tle->resjunk && old_tle->resno == attrno)
412 : {
413 100488 : new_tle = old_tle;
414 100488 : tlist_item = lnext(tlist, tlist_item);
415 : }
416 : }
417 :
418 114552 : if (new_tle == NULL)
419 : {
420 : /*
421 : * Didn't find a matching tlist entry, so make one.
422 : *
423 : * INSERTs should insert NULL in this case. (We assume the
424 : * rewriter would have inserted any available non-NULL default
425 : * value.) Also, normally we must apply any domain constraints
426 : * that might exist --- this is to catch domain NOT NULL.
427 : *
428 : * When generating a NULL constant for a dropped column, we label
429 : * it INT4 (any other guaranteed-to-exist datatype would do as
430 : * well). We can't label it with the dropped column's datatype
431 : * since that might not exist anymore. It does not really matter
432 : * what we claim the type is, since NULL is NULL --- its
433 : * representation is datatype-independent. This could perhaps
434 : * confuse code comparing the finished plan to the target
435 : * relation, however.
436 : *
437 : * Another exception is that if the column is generated, the value
438 : * we produce here will be ignored, and we don't want to risk
439 : * throwing an error. So in that case we *don't* want to apply
440 : * domain constraints, so we must produce a NULL of the base type.
441 : * Again, code comparing the finished plan to the target relation
442 : * must account for this.
443 : */
444 : Node *new_expr;
445 :
446 14064 : if (att_tup->attisdropped)
447 : {
448 : /* Insert NULL for dropped column */
449 545 : new_expr = (Node *) makeConst(INT4OID,
450 : -1,
451 : InvalidOid,
452 : sizeof(int32),
453 : (Datum) 0,
454 : true, /* isnull */
455 : true /* byval */ );
456 : }
457 13519 : else if (att_tup->attgenerated)
458 : {
459 : /* Generated column, insert a NULL of the base type */
460 921 : Oid baseTypeId = att_tup->atttypid;
461 921 : int32 baseTypeMod = att_tup->atttypmod;
462 :
463 921 : baseTypeId = getBaseTypeAndTypmod(baseTypeId, &baseTypeMod);
464 921 : new_expr = (Node *) makeConst(baseTypeId,
465 : baseTypeMod,
466 : att_tup->attcollation,
467 921 : att_tup->attlen,
468 : (Datum) 0,
469 : true, /* isnull */
470 921 : att_tup->attbyval);
471 : }
472 : else
473 : {
474 : /* Normal column, insert a NULL of the column datatype */
475 12598 : new_expr = coerce_null_to_domain(att_tup->atttypid,
476 : att_tup->atttypmod,
477 : att_tup->attcollation,
478 12598 : att_tup->attlen,
479 12598 : att_tup->attbyval);
480 : /* Must run expression preprocessing on any non-const nodes */
481 12598 : if (!IsA(new_expr, Const))
482 55 : new_expr = eval_const_expressions(root, new_expr);
483 : }
484 :
485 14064 : new_tle = makeTargetEntry((Expr *) new_expr,
486 : attrno,
487 14064 : pstrdup(NameStr(att_tup->attname)),
488 : false);
489 : }
490 :
491 114552 : new_tlist = lappend(new_tlist, new_tle);
492 : }
493 :
494 : /*
495 : * The remaining tlist entries should be resjunk; append them all to the
496 : * end of the new tlist, making sure they have resnos higher than the last
497 : * real attribute. (Note: although the rewriter already did such
498 : * renumbering, we have to do it again here in case we added NULL entries
499 : * above.)
500 : */
501 49142 : while (tlist_item)
502 : {
503 0 : TargetEntry *old_tle = (TargetEntry *) lfirst(tlist_item);
504 :
505 0 : if (!old_tle->resjunk)
506 0 : elog(ERROR, "targetlist is not sorted correctly");
507 : /* Get the resno right, but don't copy unnecessarily */
508 0 : if (old_tle->resno != attrno)
509 : {
510 0 : old_tle = flatCopyTargetEntry(old_tle);
511 0 : old_tle->resno = attrno;
512 : }
513 0 : new_tlist = lappend(new_tlist, old_tle);
514 0 : attrno++;
515 0 : tlist_item = lnext(tlist, tlist_item);
516 : }
517 :
518 49142 : return new_tlist;
519 : }
520 :
521 :
522 : /*
523 : * Locate PlanRowMark for given RT index, or return NULL if none
524 : *
525 : * This probably ought to be elsewhere, but there's no very good place
526 : */
527 : PlanRowMark *
528 16885 : get_plan_rowmark(List *rowmarks, Index rtindex)
529 : {
530 : ListCell *l;
531 :
532 17903 : foreach(l, rowmarks)
533 : {
534 2731 : PlanRowMark *rc = (PlanRowMark *) lfirst(l);
535 :
536 2731 : if (rc->rti == rtindex)
537 1713 : return rc;
538 : }
539 15172 : return NULL;
540 : }
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